/* vi: set sw=4 ts=4: */
/*
 * httpd implementation for busybox
 *
 * Copyright (C) 2002,2003 Glenn Engel <glenne@engel.org>
 * Copyright (C) 2003-2006 Vladimir Oleynik <dzo@simtreas.ru>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 *
 *****************************************************************************
 *
 * Typical usage:
 * For non root user:
 *      httpd -p 8080 -h $HOME/public_html
 * For daemon start from rc script with uid=0:
 *      httpd -u www
 * which is equivalent to (assuming user www has uid 80):
 *      httpd -p 80 -u 80 -h $PWD -c /etc/httpd.conf -r "Web Server Authentication"
 *
 * When an url starts with "/cgi-bin/" it is assumed to be a cgi script.
 * The server changes directory to the location of the script and executes it
 * after setting QUERY_STRING and other environment variables.
 *
 * If directory URL is given, no index.html is found and CGI support is enabled,
 * cgi-bin/index.cgi will be run. Directory to list is ../$QUERY_STRING.
 * See httpd_indexcgi.c for an example GCI code.
 *
 * Doc:
 * "CGI Environment Variables": http://hoohoo.ncsa.uiuc.edu/cgi/env.html
 *
 * The applet can also be invoked as an url arg decoder and html text encoder
 * as follows:
 *      foo=`httpd -d $foo`             # decode "Hello%20World" as "Hello World"
 *      bar=`httpd -e "<Hello World>"`  # encode as "&#60Hello&#32World&#62"
 * Note that url encoding for arguments is not the same as html encoding for
 * presentation.  -d decodes an url-encoded argument while -e encodes in html
 * for page display.
 *
 * httpd.conf has the following format:
 *
 * H:/serverroot     # define the server root. It will override -h
 * A:172.20.         # Allow address from 172.20.0.0/16
 * A:10.0.0.0/25     # Allow any address from 10.0.0.0-10.0.0.127
 * A:10.0.0.0/255.255.255.128  # Allow any address that previous set
 * A:127.0.0.1       # Allow local loopback connections
 * D:*               # Deny from other IP connections
 * E404:/path/e404.html # /path/e404.html is the 404 (not found) error page
 * I:index.html      # Show index.html when a directory is requested
 *
 * P:/url:[http://]hostname[:port]/new/path
 *                   # When /urlXXXXXX is requested, reverse proxy
 *                   # it to http://hostname[:port]/new/pathXXXXXX
 *
 * /cgi-bin:foo:bar  # Require user foo, pwd bar on urls starting with /cgi-bin/
 * /adm:admin:setup  # Require user admin, pwd setup on urls starting with /adm/
 * /adm:toor:PaSsWd  # or user toor, pwd PaSsWd on urls starting with /adm/
 * /adm:root:*       # or user root, pwd from /etc/passwd on urls starting with /adm/
 * /wiki:*:*         # or any user from /etc/passwd with according pwd on urls starting with /wiki/
 * .au:audio/basic   # additional mime type for audio.au files
 * *.php:/path/php   # run xxx.php through an interpreter
 *
 * A/D may be as a/d or allow/deny - only first char matters.
 * Deny/Allow IP logic:
 *  - Default is to allow all (Allow all (A:*) is a no-op).
 *  - Deny rules take precedence over allow rules.
 *  - "Deny all" rule (D:*) is applied last.
 *
 * Example:
 *   1. Allow only specified addresses
 *     A:172.20          # Allow any address that begins with 172.20.
 *     A:10.10.          # Allow any address that begins with 10.10.
 *     A:127.0.0.1       # Allow local loopback connections
 *     D:*               # Deny from other IP connections
 *
 *   2. Only deny specified addresses
 *     D:1.2.3.        # deny from 1.2.3.0 - 1.2.3.255
 *     D:2.3.4.        # deny from 2.3.4.0 - 2.3.4.255
 *     A:*             # (optional line added for clarity)
 *
 * If a sub directory contains config file, it is parsed and merged with
 * any existing settings as if it was appended to the original configuration.
 *
 * subdir paths are relative to the containing subdir and thus cannot
 * affect the parent rules.
 *
 * Note that since the sub dir is parsed in the forked thread servicing the
 * subdir http request, any merge is discarded when the process exits.  As a
 * result, the subdir settings only have a lifetime of a single request.
 *
 * Custom error pages can contain an absolute path or be relative to
 * 'home_httpd'. Error pages are to be static files (no CGI or script). Error
 * page can only be defined in the root configuration file and are not taken
 * into account in local (directories) config files.
 *
 * If -c is not set, an attempt will be made to open the default
 * root configuration file.  If -c is set and the file is not found, the
 * server exits with an error.
 */
//config:config HTTPD
//config:       bool "httpd (32 kb)"
//config:       default y
//config:       help
//config:       HTTP server.
//config:
//config:config FEATURE_HTTPD_PORT_DEFAULT
//config:       int "Default port"
//config:       default 80
//config:       range 1 65535
//config:       depends on HTTPD
//config:
//config:config FEATURE_HTTPD_RANGES
//config:       bool "Support 'Ranges:' header"
//config:       default y
//config:       depends on HTTPD
//config:       help
//config:       Makes httpd emit "Accept-Ranges: bytes" header and understand
//config:       "Range: bytes=NNN-[MMM]" header. Allows for resuming interrupted
//config:       downloads, seeking in multimedia players etc.
//config:
//config:config FEATURE_HTTPD_SETUID
//config:       bool "Enable -u <user> option"
//config:       default y
//config:       depends on HTTPD
//config:       help
//config:       This option allows the server to run as a specific user
//config:       rather than defaulting to the user that starts the server.
//config:       Use of this option requires special privileges to change to a
//config:       different user.
//config:
//config:config FEATURE_HTTPD_BASIC_AUTH
//config:       bool "Enable HTTP authentication"
//config:       default y
//config:       depends on HTTPD
//config:       help
//config:       Utilizes password settings from /etc/httpd.conf for basic
//config:       authentication on a per url basis.
//config:       Example for httpd.conf file:
//config:       /adm:toor:PaSsWd
//config:
//config:config FEATURE_HTTPD_AUTH_MD5
//config:       bool "Support MD5-encrypted passwords in HTTP authentication"
//config:       default y
//config:       depends on FEATURE_HTTPD_BASIC_AUTH
//config:       help
//config:       Enables encrypted passwords, and wildcard user/passwords
//config:       in httpd.conf file.
//config:       User '*' means 'any system user name is ok',
//config:       password of '*' means 'use system password for this user'
//config:       Examples:
//config:       /adm:toor:$1$P/eKnWXS$aI1aPGxT.dJD5SzqAKWrF0
//config:       /adm:root:*
//config:       /wiki:*:*
//config:
//config:config FEATURE_HTTPD_CGI
//config:       bool "Support Common Gateway Interface (CGI)"
//config:       default y
//config:       depends on HTTPD
//config:       help
//config:       This option allows scripts and executables to be invoked
//config:       when specific URLs are requested.
//config:
//config:config FEATURE_HTTPD_CONFIG_WITH_SCRIPT_INTERPR
//config:       bool "Support running scripts through an interpreter"
//config:       default y
//config:       depends on FEATURE_HTTPD_CGI
//config:       help
//config:       This option enables support for running scripts through an
//config:       interpreter. Turn this on if you want PHP scripts to work
//config:       properly. You need to supply an additional line in your
//config:       httpd.conf file:
//config:       *.php:/path/to/your/php
//config:
//config:config FEATURE_HTTPD_SET_REMOTE_PORT_TO_ENV
//config:       bool "Set REMOTE_PORT environment variable for CGI"
//config:       default y
//config:       depends on FEATURE_HTTPD_CGI
//config:       help
//config:       Use of this option can assist scripts in generating
//config:       references that contain a unique port number.
//config:
//config:config FEATURE_HTTPD_ENCODE_URL_STR
//config:       bool "Enable -e option (useful for CGIs written as shell scripts)"
//config:       default y
//config:       depends on HTTPD
//config:       help
//config:       This option allows html encoding of arbitrary strings for display
//config:       by the browser. Output goes to stdout.
//config:       For example, httpd -e "<Hello World>" produces
//config:       "&#60Hello&#32World&#62".
//config:
//config:config FEATURE_HTTPD_ERROR_PAGES
//config:       bool "Support custom error pages"
//config:       default y
//config:       depends on HTTPD
//config:       help
//config:       This option allows you to define custom error pages in
//config:       the configuration file instead of the default HTTP status
//config:       error pages. For instance, if you add the line:
//config:               E404:/path/e404.html
//config:       in the config file, the server will respond the specified
//config:       '/path/e404.html' file instead of the terse '404 NOT FOUND'
//config:       message.
//config:
//config:config FEATURE_HTTPD_PROXY
//config:       bool "Support reverse proxy"
//config:       default y
//config:       depends on HTTPD
//config:       help
//config:       This option allows you to define URLs that will be forwarded
//config:       to another HTTP server. To setup add the following line to the
//config:       configuration file
//config:               P:/url/:http://hostname[:port]/new/path/
//config:       Then a request to /url/myfile will be forwarded to
//config:       http://hostname[:port]/new/path/myfile.
//config:
//config:config FEATURE_HTTPD_GZIP
//config:       bool "Support GZIP content encoding"
//config:       default y
//config:       depends on HTTPD
//config:       help
//config:       Makes httpd send files using GZIP content encoding if the
//config:       client supports it and a pre-compressed <file>.gz exists.
//config:
//config:config FEATURE_HTTPD_ETAG
//config:       bool "Support caching via ETag header"
//config:       default y
//config:       depends on HTTPD
//config:       help
//config:       If server responds with ETag then next time client (browser)
//config:       resend it via If-None-Match header.
//config:       Then httpd will check if file wasn't modified and if not,
//config:       return 304 Not Modified status code.
//config:       The ETag value is constructed from last modification date
//config:       in unix epoch, and size: "hex(last_mod)-hex(file_size)".
//config:       It's not completely reliable as hash functions but fair enough.
//config:
//config:config FEATURE_HTTPD_LAST_MODIFIED
//config:       bool "Add Last-Modified header to response"
//config:       default y
//config:       depends on HTTPD
//config:       help
//config:       The Last-Modified header is used for cache validation.
//config:       The client sends last seen mtime to server in If-Modified-Since.
//config:       Both headers MUST be an RFC 1123 formatted, which is hard to parse.
//config:       Use ETag header instead.
//config:
//config:config FEATURE_HTTPD_DATE
//config:       bool "Add Date header to response"
//config:       default y
//config:       depends on HTTPD
//config:       help
//config:       RFC2616 says that server MUST add Date header to response.
//config:       But it is almost useless and can be omitted.
//config:
//config:config FEATURE_HTTPD_ACL_IP
//config:       bool "ACL IP"
//config:       default y
//config:       depends on HTTPD
//config:       help
//config:       Support IP deny/allow rules

//applet:IF_HTTPD(APPLET(httpd, BB_DIR_USR_SBIN, BB_SUID_DROP))

//kbuild:lib-$(CONFIG_HTTPD) += httpd.o

//usage:#define httpd_trivial_usage
//usage:       "[-ifv[v]]"
//usage:       " [-c CONFFILE]"
//usage:       " [-p [IP:]PORT]"
//usage:        IF_FEATURE_HTTPD_SETUID(" [-u USER[:GRP]]")
//usage:        IF_FEATURE_HTTPD_BASIC_AUTH(" [-r REALM]")
//usage:       " [-h HOME]\n"
//usage:       "or httpd -d/-e" IF_FEATURE_HTTPD_AUTH_MD5("/-m") " STRING"
//usage:#define httpd_full_usage "\n\n"
//usage:       "Listen for incoming HTTP requests\n"
//usage:     "\n        -i              Inetd mode"
//usage:     "\n        -f              Run in foreground"
//usage:     "\n        -v[v]           Verbose"
//usage:     "\n        -p [IP:]PORT    Bind to IP:PORT (default *:"STR(CONFIG_FEATURE_HTTPD_PORT_DEFAULT)")"
//usage:        IF_FEATURE_HTTPD_SETUID(
//usage:     "\n        -u USER[:GRP]   Set uid/gid after binding to port")
//usage:        IF_FEATURE_HTTPD_BASIC_AUTH(
//usage:     "\n        -r REALM        Authentication Realm for Basic Authentication")
//usage:     "\n        -h HOME         Home directory (default .)"
//usage:     "\n        -c FILE         Configuration file (default {/etc,HOME}/httpd.conf)"
//usage:        IF_FEATURE_HTTPD_AUTH_MD5(
//usage:     "\n        -m STRING       MD5 crypt STRING")
//usage:     "\n        -e STRING       HTML encode STRING"
//usage:     "\n        -d STRING       URL decode STRING"

/* TODO: use TCP_CORK, parse_config() */

#include "libbb.h"
#include "common_bufsiz.h"
#if ENABLE_PAM
/* PAM may include <locale.h>. We may need to undefine bbox's stub define: */
# undef setlocale
/* For some obscure reason, PAM is not in pam/xxx, but in security/xxx.
 * Apparently they like to confuse people. */
# include <security/pam_appl.h>
# include <security/pam_misc.h>
#endif
#if ENABLE_FEATURE_USE_SENDFILE
# include <sys/sendfile.h>
#endif

/* see sys/netinet6/in6.h */
#if defined(__FreeBSD__)
# define s6_addr32 __u6_addr.__u6_addr32
#endif

#define DEBUG 0

#if DEBUG
# define dbg(...) fprintf(stderr, __VA_ARGS__)
#else
# define dbg(...) ((void)0)
#endif

#define IOBUF_SIZE 8192
#define MAX_HTTP_HEADERS_SIZE (32*1024)

#define HEADER_READ_TIMEOUT 60

#define STR1(s) #s
#define STR(s) STR1(s)

static const char DEFAULT_PATH_HTTPD_CONF[] ALIGN1 = "/etc";
static const char HTTPD_CONF[] ALIGN1 = "httpd.conf";
static const char HTTP_200[] ALIGN1 = "HTTP/1.1 200 OK\r\n";
static const char index_html[] ALIGN1 = "index.html";

typedef struct has_next_ptr {
        struct has_next_ptr *next;
} has_next_ptr;

/* Must have "next" as a first member */
typedef struct Htaccess {
        struct Htaccess *next;
        char *after_colon;
        char before_colon[1];  /* really bigger, must be last */
} Htaccess;

#if ENABLE_FEATURE_HTTPD_ACL_IP
/* Must have "next" as a first member */
typedef struct Htaccess_IP {
        struct Htaccess_IP *next;
        unsigned ip;
        unsigned mask;
        int allow_deny;
} Htaccess_IP;
#endif

/* Must have "next" as a first member */
typedef struct Htaccess_Proxy {
        struct Htaccess_Proxy *next;
        char *url_from;
        char *host_port;
        char *url_to;
} Htaccess_Proxy;

enum {
        HTTP_OK = 200,
        HTTP_PARTIAL_CONTENT = 206,
        HTTP_MOVED_TEMPORARILY = 302,
        HTTP_NOT_MODIFIED = 304,
        HTTP_BAD_REQUEST = 400,       /* malformed syntax */
        HTTP_UNAUTHORIZED = 401, /* authentication needed, respond with auth hdr */
        HTTP_NOT_FOUND = 404,
        HTTP_FORBIDDEN = 403,
        HTTP_REQUEST_TIMEOUT = 408,
        HTTP_NOT_IMPLEMENTED = 501,   /* used for unrecognized requests */
        HTTP_INTERNAL_SERVER_ERROR = 500,
        HTTP_ENTITY_TOO_LARGE = 413,
        HTTP_CONTINUE = 100,
#if 0   /* future use */
        HTTP_SWITCHING_PROTOCOLS = 101,
        HTTP_CREATED = 201,
        HTTP_ACCEPTED = 202,
        HTTP_NON_AUTHORITATIVE_INFO = 203,
        HTTP_NO_CONTENT = 204,
        HTTP_MULTIPLE_CHOICES = 300,
        HTTP_MOVED_PERMANENTLY = 301,
        HTTP_PAYMENT_REQUIRED = 402,
        HTTP_BAD_GATEWAY = 502,
        HTTP_SERVICE_UNAVAILABLE = 503, /* overload, maintenance */
#endif
};

static const uint16_t http_response_type[] ALIGN2 = {
        HTTP_OK,
#if ENABLE_FEATURE_HTTPD_RANGES
        HTTP_PARTIAL_CONTENT,
#endif
        HTTP_MOVED_TEMPORARILY,
#if ENABLE_FEATURE_HTTPD_ETAG
        HTTP_NOT_MODIFIED,
#endif
        HTTP_REQUEST_TIMEOUT,
        HTTP_NOT_IMPLEMENTED,
#if ENABLE_FEATURE_HTTPD_BASIC_AUTH
        HTTP_UNAUTHORIZED,
#endif
        HTTP_NOT_FOUND,
        HTTP_BAD_REQUEST,
        HTTP_FORBIDDEN,
        HTTP_INTERNAL_SERVER_ERROR,
        HTTP_ENTITY_TOO_LARGE,
#if 0   /* not implemented */
        HTTP_CREATED,
        HTTP_ACCEPTED,
        HTTP_NO_CONTENT,
        HTTP_MULTIPLE_CHOICES,
        HTTP_MOVED_PERMANENTLY,
        HTTP_BAD_GATEWAY,
        HTTP_SERVICE_UNAVAILABLE,
#endif
};

static const struct {
        const char *name;
        const char *info;
} http_response[ARRAY_SIZE(http_response_type)] = {
        { "OK", NULL },
#if ENABLE_FEATURE_HTTPD_RANGES
        { "Partial Content", NULL },
#endif
        { "Found", NULL },
#if ENABLE_FEATURE_HTTPD_ETAG
        { "Not Modified" },
#endif
        { "Request Timeout", "No request appeared within 60 seconds" },
        { "Not Implemented", "The requested method is not recognized" },
#if ENABLE_FEATURE_HTTPD_BASIC_AUTH
        { "Unauthorized", "" },
#endif
        { "Not Found", "The requested URL was not found" },
        { "Bad Request", "Unsupported method" },
        { "Forbidden", ""  },
        { "Internal Server Error", "Internal Server Error" },
        { "Entity Too Large", "Entity Too Large" },
#if 0   /* not implemented */
        { "Created" },
        { "Accepted" },
        { "No Content" },
        { "Multiple Choices" },
        { "Moved Permanently" },
        { "Bad Gateway", "" },
        { "Service Unavailable", "" },
#endif
};

struct globals {
        int verbose;            /* must be int (used by getopt32) */
        smallint flg_deny_all;
#if ENABLE_FEATURE_HTTPD_GZIP
        /* client can handle gzip / we are going to send gzip */
        smallint content_gzip;
#endif
        time_t last_mod;
#if ENABLE_FEATURE_HTTPD_ETAG
        char *if_none_match;
#endif
        char *rmt_ip_str;       /* for $REMOTE_ADDR and $REMOTE_PORT */
        const char *bind_addr_or_port;

        char *g_query;
        const char *opt_c_configFile;
        const char *home_httpd;
        const char *index_page;

        const char *found_mime_type;
        const char *found_moved_temporarily;
#if ENABLE_FEATURE_HTTPD_ACL_IP
        Htaccess_IP *ip_a_d;    /* config allow/deny lines */
#endif

        IF_FEATURE_HTTPD_BASIC_AUTH(const char *g_realm;)
        IF_FEATURE_HTTPD_BASIC_AUTH(char *remoteuser;)

        off_t file_size;        /* -1 - unknown */
#if ENABLE_FEATURE_HTTPD_RANGES
        off_t range_start;
        off_t range_end;
        off_t range_len;
#endif

#if ENABLE_FEATURE_HTTPD_BASIC_AUTH
        Htaccess *g_auth;       /* config user:password lines */
#endif
        Htaccess *mime_a;       /* config mime types */
#if ENABLE_FEATURE_HTTPD_CONFIG_WITH_SCRIPT_INTERPR
        Htaccess *script_i;     /* config script interpreters */
#endif
        char *iobuf;            /* [IOBUF_SIZE] */
#define        hdr_buf bb_common_bufsiz1
#define sizeof_hdr_buf COMMON_BUFSIZE
        char *hdr_ptr;
        int hdr_cnt;
#if ENABLE_FEATURE_HTTPD_ETAG
        char etag[sizeof("'%llx-%llx'") + 2 * sizeof(long long)*3];
#endif
#if ENABLE_FEATURE_HTTPD_ERROR_PAGES
        const char *http_error_page[ARRAY_SIZE(http_response_type)];
#endif
#if ENABLE_FEATURE_HTTPD_PROXY
        Htaccess_Proxy *proxy;
#endif
};
#define G (*ptr_to_globals)
#define verbose           (G.verbose          )
#define flg_deny_all      (G.flg_deny_all     )
#if ENABLE_FEATURE_HTTPD_GZIP
# define content_gzip     (G.content_gzip     )
#else
# define content_gzip     0
#endif
#define bind_addr_or_port (G.bind_addr_or_port)
#define g_query           (G.g_query          )
#define opt_c_configFile  (G.opt_c_configFile )
#define home_httpd        (G.home_httpd       )
#define index_page        (G.index_page       )
#define found_mime_type   (G.found_mime_type  )
#define found_moved_temporarily (G.found_moved_temporarily)
#define last_mod          (G.last_mod         )
#define g_realm           (G.g_realm          )
#define remoteuser        (G.remoteuser       )
#define file_size         (G.file_size        )
#if ENABLE_FEATURE_HTTPD_RANGES
#define range_start       (G.range_start      )
#define range_end         (G.range_end        )
#define range_len         (G.range_len        )
#else
enum {
        range_start = -1,
        range_end = MAXINT(off_t) - 1,
        range_len = MAXINT(off_t),
};
#endif
#define rmt_ip_str        (G.rmt_ip_str       )
#define g_auth            (G.g_auth           )
#define mime_a            (G.mime_a           )
#define script_i          (G.script_i         )
#define iobuf             (G.iobuf            )
#define hdr_ptr           (G.hdr_ptr          )
#define hdr_cnt           (G.hdr_cnt          )
#define http_error_page   (G.http_error_page  )
#define proxy             (G.proxy            )
#define INIT_G() do { \
        setup_common_bufsiz(); \
        SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
        IF_FEATURE_HTTPD_BASIC_AUTH(g_realm = "Web Server Authentication";) \
        IF_FEATURE_HTTPD_RANGES(range_start = -1;) \
        bind_addr_or_port = STR(CONFIG_FEATURE_HTTPD_PORT_DEFAULT); \
        index_page = index_html; \
        file_size = -1; \
} while (0)


#define STRNCASECMP(a, str) strncasecmp((a), (str), sizeof(str)-1)

/* Prototypes */
enum {
        SEND_HEADERS     = (1 << 0),
        SEND_BODY        = (1 << 1),
};
static void send_file_and_exit(const char *url, int what) NORETURN;

static void free_llist(has_next_ptr **pptr)
{
        has_next_ptr *cur = *pptr;
        while (cur) {
                has_next_ptr *t = cur;
                cur = cur->next;
                free(t);
        }
        *pptr = NULL;
}

static ALWAYS_INLINE void free_Htaccess_list(Htaccess **pptr)
{
        free_llist((has_next_ptr**)pptr);
}

#if ENABLE_FEATURE_HTTPD_ACL_IP
static ALWAYS_INLINE void free_Htaccess_IP_list(Htaccess_IP **pptr)
{
        free_llist((has_next_ptr**)pptr);
}
#endif

#if ENABLE_FEATURE_HTTPD_ACL_IP
/* Returns presumed mask width in bits or < 0 on error.
 * Updates strp, stores IP at provided pointer */
static int scan_ip(const char **strp, unsigned *ipp, unsigned char endc)
{
        const char *p = *strp;
        int auto_mask = 8;
        unsigned ip = 0;
        int j;

        if (*p == '/')
                return -auto_mask;

        for (j = 0; j < 4; j++) {
                unsigned octet;

                if ((*p < '0' || *p > '9') && *p != '/' && *p)
                        return -auto_mask;
                octet = 0;
                while (*p >= '0' && *p <= '9') {
                        octet *= 10;
                        octet += *p - '0';
                        if (octet > 255)
                                return -auto_mask;
                        p++;
                }
                if (*p == '.')
                        p++;
                if (*p != '/' && *p)
                        auto_mask += 8;
                ip = (ip << 8) | octet;
        }
        if (*p) {
                if (*p != endc)
                        return -auto_mask;
                p++;
                if (*p == '\0')
                        return -auto_mask;
        }
        *ipp = ip;
        *strp = p;
        return auto_mask;
}

/* Returns 0 on success. Stores IP and mask at provided pointers */
static int scan_ip_mask(const char *str, unsigned *ipp, unsigned *maskp)
{
        int i;
        unsigned mask;
        char *p;

        i = scan_ip(&str, ipp, '/');
        if (i < 0)
                return i;

        if (*str) {
                /* there is /xxx after dotted-IP address */
                i = bb_strtou(str, &p, 10);
                if (*p == '.') {
                        /* 'xxx' itself is dotted-IP mask, parse it */
                        /* (return 0 (success) only if it has N.N.N.N form) */
                        return scan_ip(&str, maskp, '\0') - 32;
                }
                if (*p)
                        return -1;
        }

        if (i > 32)
                return -1;

        if (sizeof(unsigned) == 4 && i == 32) {
                /* mask >>= 32 below may not work */
                mask = 0;
        } else {
                mask = 0xffffffff;
                mask >>= i;
        }
        /* i == 0 -> *maskp = 0x00000000
         * i == 1 -> *maskp = 0x80000000
         * i == 4 -> *maskp = 0xf0000000
         * i == 31 -> *maskp = 0xfffffffe
         * i == 32 -> *maskp = 0xffffffff */
        *maskp = (uint32_t)(~mask);
        return 0;
}
#endif

/*
 * Parse configuration file into in-memory linked list.
 *
 * Any previous IP rules are discarded.
 * If the flag argument is not SUBDIR_PARSE then all /path and mime rules
 * are also discarded.  That is, previous settings are retained if flag is
 * SUBDIR_PARSE.
 * Error pages are only parsed on the main config file.
 *
 * path   Path where to look for httpd.conf (without filename).
 * flag   Type of the parse request.
 */
/* flag param: */
enum {
        FIRST_PARSE    = 0, /* path will be "/etc" */
        SIGNALED_PARSE = 1, /* path will be "/etc" */
        SUBDIR_PARSE   = 2, /* path will be derived from URL */
};
static int parse_conf(const char *path, int flag)
{
        /* internally used extra flag state */
        enum { TRY_CURDIR_PARSE = 3 };

        FILE *f;
        const char *filename;
        char buf[160];

        /* discard old rules */
#if ENABLE_FEATURE_HTTPD_ACL_IP
        free_Htaccess_IP_list(&G.ip_a_d);
#endif
        flg_deny_all = 0;
        /* retain previous auth and mime config only for subdir parse */
        if (flag != SUBDIR_PARSE) {
                free_Htaccess_list(&mime_a);
#if ENABLE_FEATURE_HTTPD_BASIC_AUTH
                free_Htaccess_list(&g_auth);
#endif
#if ENABLE_FEATURE_HTTPD_CONFIG_WITH_SCRIPT_INTERPR
                free_Htaccess_list(&script_i);
#endif
        }

        filename = opt_c_configFile;
        if (flag == SUBDIR_PARSE || filename == NULL) {
                filename = alloca(strlen(path) + sizeof(HTTPD_CONF) + 2);
                sprintf((char *)filename, "%s/%s", path, HTTPD_CONF);
        }

        while ((f = fopen_for_read(filename)) == NULL) {
                if (flag >= SUBDIR_PARSE) { /* SUBDIR or TRY_CURDIR */
                        /* config file not found, no changes to config */
                        return -1;
                }
                if (flag == FIRST_PARSE) {
                        /* -c CONFFILE given, but CONFFILE doesn't exist? */
                        if (opt_c_configFile)
                                bb_simple_perror_msg_and_die(opt_c_configFile);
                        /* else: no -c, thus we looked at /etc/httpd.conf,
                         * and it's not there. try ./httpd.conf: */
                }
                flag = TRY_CURDIR_PARSE;
                filename = HTTPD_CONF;
        }

#if ENABLE_FEATURE_HTTPD_BASIC_AUTH
        /* in "/file:user:pass" lines, we prepend path in subdirs */
        if (flag != SUBDIR_PARSE)
                path = "";
#endif
        /* The lines can be:
         *
         * I:default_index_file
         * H:http_home
         * [AD]:IP[/mask]   # allow/deny, * for wildcard
         * Ennn:error.html  # error page for status nnn
         * P:/url:[http://]hostname[:port]/new/path # reverse proxy
         * .ext:mime/type   # mime type
         * *.php:/path/php  # run xxx.php through an interpreter
         * /file:user:pass  # username and password
         */
        while (fgets(buf, sizeof(buf), f) != NULL) {
                unsigned strlen_buf;
                unsigned char ch;
                char *after_colon;

                { /* remove all whitespace, and # comments */
                        char *p, *p0;

                        p0 = buf;
                        /* skip non-whitespace beginning. Often the whole line
                         * is non-whitespace. We want this case to work fast,
                         * without needless copying, therefore we don't merge
                         * this operation into next while loop. */
                        while ((ch = *p0) != '\0' && ch != '\n' && ch != '#'
                         && ch != ' ' && ch != '\t'
                        ) {
                                p0++;
                        }
                        p = p0;
                        /* if we enter this loop, we have some whitespace.
                         * discard it */
                        while (ch != '\0' && ch != '\n' && ch != '#') {
                                if (ch != ' ' && ch != '\t') {
                                        *p++ = ch;
                                }
                                ch = *++p0;
                        }
                        *p = '\0';
                        strlen_buf = p - buf;
                        if (strlen_buf == 0)
                                continue; /* empty line */
                }

                after_colon = strchr(buf, ':');
                /* strange line? */
                if (after_colon == NULL || *++after_colon == '\0')
                        goto config_error;

                ch = (buf[0] & ~0x20); /* toupper if it's a letter */

                if (ch == 'I') {
                        if (index_page != index_html)
                                free((char*)index_page);
                        index_page = xstrdup(after_colon);
                        continue;
                }

                /* do not allow jumping around using H in subdir's configs */
                if (flag == FIRST_PARSE && ch == 'H') {
                        home_httpd = xstrdup(after_colon);
                        xchdir(home_httpd);
                        continue;
                }

#if ENABLE_FEATURE_HTTPD_ACL_IP
                if (ch == 'A' || ch == 'D') {
                        Htaccess_IP *pip;

                        if (*after_colon == '*') {
                                if (ch == 'D') {
                                        /* memorize "deny all" */
                                        flg_deny_all = 1;
                                }
                                /* skip assumed "A:*", it is a default anyway */
                                continue;
                        }
                        /* store "allow/deny IP/mask" line */
                        pip = xzalloc(sizeof(*pip));
                        if (scan_ip_mask(after_colon, &pip->ip, &pip->mask)) {
                                /* IP{/mask} syntax error detected, protect all */
                                ch = 'D';
                                pip->mask = 0;
                        }
                        pip->allow_deny = ch;
                        if (ch == 'D') {
                                /* Deny:from_IP - prepend */
                                pip->next = G.ip_a_d;
                                G.ip_a_d = pip;
                        } else {
                                /* A:from_IP - append (thus all D's precedes A's) */
                                Htaccess_IP *prev_IP = G.ip_a_d;
                                if (prev_IP == NULL) {
                                        G.ip_a_d = pip;
                                } else {
                                        while (prev_IP->next)
                                                prev_IP = prev_IP->next;
                                        prev_IP->next = pip;
                                }
                        }
                        continue;
                }
#endif

#if ENABLE_FEATURE_HTTPD_ERROR_PAGES
                if (flag == FIRST_PARSE && ch == 'E') {
                        unsigned i;
                        int status = atoi(buf + 1); /* error status code */

                        if (status < HTTP_CONTINUE) {
                                goto config_error;
                        }
                        /* then error page; find matching status */
                        for (i = 0; i < ARRAY_SIZE(http_response_type); i++) {
                                if (http_response_type[i] == status) {
                                        /* We chdir to home_httpd, thus no need to
                                         * concat_path_file(home_httpd, after_colon)
                                         * here */
                                        http_error_page[i] = xstrdup(after_colon);
                                        break;
                                }
                        }
                        continue;
                }
#endif

#if ENABLE_FEATURE_HTTPD_PROXY
                if (flag == FIRST_PARSE && ch == 'P') {
                        /* P:/url:[http://]hostname[:port]/new/path */
                        char *url_from, *host_port, *url_to;
                        Htaccess_Proxy *proxy_entry;

                        url_from = after_colon;
                        host_port = strchr(after_colon, ':');
                        if (host_port == NULL) {
                                goto config_error;
                        }
                        *host_port++ = '\0';
                        if (is_prefixed_with(host_port, "http://"))
                                host_port += 7;
                        if (*host_port == '\0') {
                                goto config_error;
                        }
                        url_to = strchr(host_port, '/');
                        if (url_to == NULL) {
                                goto config_error;
                        }
                        *url_to = '\0';
                        proxy_entry = xzalloc(sizeof(*proxy_entry));
                        proxy_entry->url_from = xstrdup(url_from);
                        proxy_entry->host_port = xstrdup(host_port);
                        *url_to = '/';
                        proxy_entry->url_to = xstrdup(url_to);
                        proxy_entry->next = proxy;
                        proxy = proxy_entry;
                        continue;
                }
#endif
                /* the rest of directives are non-alphabetic,
                 * must avoid using "toupper'ed" ch */
                ch = buf[0];

                if (ch == '.' /* ".ext:mime/type" */
#if ENABLE_FEATURE_HTTPD_CONFIG_WITH_SCRIPT_INTERPR
                 || (ch == '*' && buf[1] == '.') /* "*.php:/path/php" */
#endif
                ) {
                        char *p;
                        Htaccess *cur;

                        cur = xzalloc(sizeof(*cur) /* includes space for NUL */ + strlen_buf);
                        strcpy(cur->before_colon, buf);
                        p = cur->before_colon + (after_colon - buf);
                        p[-1] = '\0';
                        cur->after_colon = p;
                        if (ch == '.') {
                                /* .mime line: prepend to mime_a list */
                                cur->next = mime_a;
                                mime_a = cur;
                        }
#if ENABLE_FEATURE_HTTPD_CONFIG_WITH_SCRIPT_INTERPR
                        else {
                                /* script interpreter line: prepend to script_i list */
                                cur->next = script_i;
                                script_i = cur;
                        }
#endif
                        continue;
                }

#if ENABLE_FEATURE_HTTPD_BASIC_AUTH
                if (ch == '/') { /* "/file:user:pass" */
                        char *p;
                        Htaccess *cur;
                        unsigned file_len;

                        /* note: path is "" unless we are in SUBDIR parse,
                         * otherwise it does NOT start with "/" */
                        cur = xzalloc(sizeof(*cur) /* includes space for NUL */
                                + 1 + strlen(path)
                                + strlen_buf
                                );
                        /* form "/path/file" */
                        sprintf(cur->before_colon, "/%s%.*s",
                                path,
                                (int) (after_colon - buf - 1), /* includes "/", but not ":" */
                                buf);
                        /* canonicalize it */
                        p = bb_simplify_abs_path_inplace(cur->before_colon);
                        file_len = p - cur->before_colon;
                        /* add "user:pass" after NUL */
                        strcpy(++p, after_colon);
                        cur->after_colon = p;

                        /* insert cur into g_auth */
                        /* g_auth is sorted by decreased filename length */
                        {
                                Htaccess *auth, **authp;

                                authp = &g_auth;
                                while ((auth = *authp) != NULL) {
                                        if (file_len >= strlen(auth->before_colon)) {
                                                /* insert cur before auth */
                                                cur->next = auth;
                                                break;
                                        }
                                        authp = &auth->next;
                                }
                                *authp = cur;
                        }
                        continue;
                }
#endif /* BASIC_AUTH */

                /* the line is not recognized */
 config_error:
                bb_error_msg("config error '%s' in '%s'", buf, filename);
        } /* while (fgets) */

        fclose(f);
        return 0;
}

#if ENABLE_FEATURE_HTTPD_ENCODE_URL_STR
/*
 * Given a string, html-encode special characters.
 * This is used for the -e command line option to provide an easy way
 * for scripts to encode result data without confusing browsers.  The
 * returned string pointer is memory allocated by malloc().
 *
 * Returns a pointer to the encoded string (malloced).
 */

static char *encodeString(const char *string)
{
        /* take the simple route and encode everything */
        /* could possibly scan once to get length.     */
        int len = strlen(string);
        char *out = xmalloc(len * 6 + 1);
        char *p = out;
        char ch;

        while ((ch = *string++) != '\0') {
                /* very simple check for what to encode */
                if (isalnum(ch))
                        *p++ = ch;
                else
                        p += sprintf(p, "&#%u;", (unsigned char) ch);
        }
        *p = '\0';
        return out;
}
#endif

#if ENABLE_FEATURE_HTTPD_BASIC_AUTH
/*
 * Decode a base64 data stream as per rfc1521.
 * Note that the rfc states that non base64 chars are to be ignored.
 * Since the decode always results in a shorter size than the input,
 * it is OK to pass the input arg as an output arg.
 * Parameter: a pointer to a base64 encoded string.
 * Decoded data is stored in-place.
 */
static void decodeBase64(char *data)
{
        decode_base64(data, NULL)[0] = '\0';
}
#endif

/*
 * Create a listen server socket on the designated port.
 */
static int openServer(void)
{
        unsigned n = bb_strtou(bind_addr_or_port, NULL, 10);
        if (!errno && n && n <= 0xffff)
                n = create_and_bind_stream_or_die(NULL, n);
        else
                n = create_and_bind_stream_or_die(bind_addr_or_port, 80);
        xlisten(n, 9);
        return n;
}

/*
 * Log the connection closure and exit.
 */
static void log_and_exit(void) NORETURN;
static void log_and_exit(void)
{
        /* Paranoia. IE said to be buggy. It may send some extra data
         * or be confused by us just exiting without SHUT_WR. Oh well. */
        shutdown(1, SHUT_WR);
        /* Why??
        (this also messes up stdin when user runs httpd -i from terminal)
        ndelay_on(0);
        while (read(STDIN_FILENO, iobuf, IOBUF_SIZE) > 0)
                continue;
        */

        if (verbose > 2)
                bb_simple_error_msg("closed");
        _exit(xfunc_error_retval);
}

/*
 * Create and send HTTP response headers.
 * The arguments are combined and sent as one write operation.  Note that
 * IE will puke big-time if the headers are not sent in one packet and the
 * second packet is delayed for any reason.
 * responseNum - the result code to send.
 */
static void send_headers(unsigned responseNum)
{
#if ENABLE_FEATURE_HTTPD_DATE || ENABLE_FEATURE_HTTPD_LAST_MODIFIED
        static const char RFC1123FMT[] ALIGN1 = "%a, %d %b %Y %H:%M:%S GMT";
        /* Fixed size 29-byte string. Example: Sun, 06 Nov 1994 08:49:37 GMT */
        char date_str[40]; /* using a bit larger buffer to paranoia reasons */
        struct tm tm;
#endif
        const char *responseString = "";
        const char *infoString = NULL;
#if ENABLE_FEATURE_HTTPD_ERROR_PAGES
        const char *error_page = NULL;
#endif
        unsigned len;
        unsigned i;

        for (i = 0; i < ARRAY_SIZE(http_response_type); i++) {
                if (http_response_type[i] == responseNum) {
                        responseString = http_response[i].name;
                        infoString = http_response[i].info;
#if ENABLE_FEATURE_HTTPD_ERROR_PAGES
                        error_page = http_error_page[i];
#endif
                        break;
                }
        }

        if (verbose)
                bb_error_msg("response:%u", responseNum);

        /* We use sprintf, not snprintf (it's less code).
         * iobuf[] is several kbytes long and all headers we generate
         * always fit into those kbytes.
         */

        {
#if ENABLE_FEATURE_HTTPD_DATE
                time_t timer = time(NULL);
                strftime(date_str, sizeof(date_str), RFC1123FMT, gmtime_r(&timer, &tm));
                /* ^^^ using gmtime_r() instead of gmtime() to not use static data */
#endif
                len = sprintf(iobuf,
                        "HTTP/1.1 %u %s\r\n"
#if ENABLE_FEATURE_HTTPD_DATE
                        "Date: %s\r\n"
#endif
                        "Connection: close\r\n",
                        responseNum, responseString
#if ENABLE_FEATURE_HTTPD_DATE
                        , date_str
#endif
                );
        }

        if (responseNum != HTTP_OK || found_mime_type) {
                len += sprintf(iobuf + len,
                                "Content-type: %s\r\n",
                                /* if it's error message, then it's HTML */
                                (responseNum != HTTP_OK ? "text/html" : found_mime_type)
                );
        }

#if ENABLE_FEATURE_HTTPD_BASIC_AUTH
        if (responseNum == HTTP_UNAUTHORIZED) {
                len += sprintf(iobuf + len,
                                "WWW-Authenticate: Basic realm=\"%.999s\"\r\n",
                                g_realm /* %.999s protects from overflowing iobuf[] */
                );
        }
#endif
        if (responseNum == HTTP_MOVED_TEMPORARILY) {
                /* Responding to "GET /dir" with
                 * "HTTP/1.1 302 Found" "Location: /dir/"
                 * - IOW, asking them to repeat with a slash.
                 * Here, overflow IS possible, can't use sprintf:
                 * mkdir test
                 * python -c 'print("get /test?" + ("x" * 8192))' | busybox httpd -i -h .
                 */
                len += snprintf(iobuf + len, IOBUF_SIZE-3 - len,
                                "Location: %s/%s%s\r\n",
                                found_moved_temporarily,
                                (g_query ? "?" : ""),
                                (g_query ? g_query : "")
                );
                if (len > IOBUF_SIZE-3)
                        len = IOBUF_SIZE-3;
        }

#if ENABLE_FEATURE_HTTPD_ERROR_PAGES
        if (error_page && access(error_page, R_OK) == 0) {
                iobuf[len++] = '\r';
                iobuf[len++] = '\n';
                if (DEBUG) {
                        iobuf[len] = '\0';
                        fprintf(stderr, "headers: '%s'\n", iobuf);
                }
                full_write(STDOUT_FILENO, iobuf, len);
                dbg("writing error page: '%s'\n", error_page);
                return send_file_and_exit(error_page, SEND_BODY);
        }
#endif

        if (file_size != -1) {    /* file */
#if ENABLE_FEATURE_HTTPD_LAST_MODIFIED
                strftime(date_str, sizeof(date_str), RFC1123FMT, gmtime_r(&last_mod, &tm));
#endif
#if ENABLE_FEATURE_HTTPD_RANGES
                if (responseNum == HTTP_PARTIAL_CONTENT) {
                        len += sprintf(iobuf + len,
                                "Content-Range: bytes %"OFF_FMT"u-%"OFF_FMT"u/%"OFF_FMT"u\r\n",
                                        range_start,
                                        range_end,
                                        file_size
                        );
                        file_size = range_end - range_start + 1;
                }
#endif

//RFC 2616 4.4 Message Length
// The transfer-length of a message is the length of the message-body as
// it appears in the message; that is, after any transfer-codings have
// been applied. When a message-body is included with a message, the
// transfer-length of that body is determined by one of the following
// (in order of precedence):
// 1.Any response message which "MUST NOT" include a message-body (such
//   as the 1xx, 204, and 304 responses and any response to a HEAD
//   request) is always terminated by the first empty line after the
//   header fields, regardless of the entity-header fields present in
//   the message.
// 2.If a Transfer-Encoding header field (section 14.41) is present and
//   has any value other than "identity", then the transfer-length is
//   defined by use of the "chunked" transfer-coding (section 3.6),
//   unless the message is terminated by closing the connection.
// 3.If a Content-Length header field (section 14.13) is present, its
//   decimal value in OCTETs represents both the entity-length and the
//   transfer-length. The Content-Length header field MUST NOT be sent
//   if these two lengths are different (i.e., if a Transfer-Encoding
//   header field is present). If a message is received with both a
//   Transfer-Encoding header field and a Content-Length header field,
//   the latter MUST be ignored.
// 4.If the message uses the media type "multipart/byteranges" ...
// 5.By the server closing the connection.
//
// (NB: standards do not define "Transfer-Length:" _header_,
// transfer-length above is just a concept).

                len += sprintf(iobuf + len,
#if ENABLE_FEATURE_HTTPD_RANGES
                        "Accept-Ranges: bytes\r\n"
#endif
#if ENABLE_FEATURE_HTTPD_LAST_MODIFIED
                        "Last-Modified: %s\r\n"
#endif
#if ENABLE_FEATURE_HTTPD_ETAG
                        "ETag: %s\r\n"
#endif

        /* Because of 4.4 (5), we can forgo sending of "Content-Length"
         * since we close connection afterwards, but it helps clients
         * to e.g. estimate download times, show progress bars etc.
         * Theoretically we should not send it if page is compressed,
         * but de-facto standard is to send it (see comment below).
         */
                        "Content-Length: %"OFF_FMT"u\r\n",
#if ENABLE_FEATURE_HTTPD_LAST_MODIFIED
                                date_str,
#endif
#if ENABLE_FEATURE_HTTPD_ETAG
                                G.etag,
#endif
                                file_size
                );
        }

        /* This should be "Transfer-Encoding", not "Content-Encoding":
         * "data is compressed for transfer", not "data is an archive".
         * But many clients were not handling "Transfer-Encoding" correctly
         * (they were not uncompressing gzipped pages, tried to show
         * raw compressed data), and servers worked around it by using
         * "Content-Encoding" instead... and this become de-facto standard.
         * https://bugzilla.mozilla.org/show_bug.cgi?id=68517
         * https://bugs.chromium.org/p/chromium/issues/detail?id=94730
         */
        if (content_gzip)
                len += sprintf(iobuf + len, "Content-Encoding: gzip\r\n");

        iobuf[len++] = '\r';
        iobuf[len++] = '\n';
        if (infoString) {
                len += sprintf(iobuf + len,
                                "<HTML><HEAD><TITLE>%u %s</TITLE></HEAD>\n"
                                "<BODY><H1>%u %s</H1>\n"
                                "%s\n"
                                "</BODY></HTML>\n",
                                responseNum, responseString,
                                responseNum, responseString,
                                infoString
                );
        }
        if (DEBUG) {
                iobuf[len] = '\0';
                fprintf(stderr, "headers: '%s'\n", iobuf);
        }
        if (full_write(STDOUT_FILENO, iobuf, len) != len) {
                if (verbose > 1)
                        bb_simple_perror_msg("error");
                log_and_exit();
        }
}

static void send_headers_and_exit(int responseNum) NORETURN;
static void send_headers_and_exit(int responseNum)
{
        IF_FEATURE_HTTPD_GZIP(content_gzip = 0;)
        file_size = -1; /* no Last-Modified:, ETag:, Content-Length: */
        send_headers(responseNum);
        log_and_exit();
}

/*
 * Read from the socket until '\n' or EOF.
 * '\r' chars are removed.
 * '\n' is replaced with NUL.
 * Return number of characters read or 0 if nothing is read
 * ('\r' and '\n' are not counted).
 * Data is returned in iobuf.
 */
static unsigned get_line(void)
{
        unsigned count;
        char c;

        count = 0;
        while (1) {
                if (hdr_cnt <= 0) {
                        alarm(HEADER_READ_TIMEOUT);
                        hdr_cnt = safe_read(STDIN_FILENO, hdr_buf, sizeof_hdr_buf);
                        if (hdr_cnt <= 0)
                                goto ret;
                        hdr_ptr = hdr_buf;
                }
                hdr_cnt--;
                c = *hdr_ptr++;
                if (c == '\r')
                        continue;
                if (c == '\n')
                        break;
                iobuf[count] = c;
                if (count < (IOBUF_SIZE - 1))      /* check overflow */
                        count++;
        }
 ret:
        iobuf[count] = '\0';
        return count;
}

#if ENABLE_FEATURE_HTTPD_CGI || ENABLE_FEATURE_HTTPD_PROXY

/* gcc 4.2.1 fares better with NOINLINE */
static NOINLINE void cgi_io_loop_and_exit(int fromCgi_rd, int toCgi_wr, int post_len) NORETURN;
static NOINLINE void cgi_io_loop_and_exit(int fromCgi_rd, int toCgi_wr, int post_len)
{
        enum { FROM_CGI = 1, TO_CGI = 2 }; /* indexes in pfd[] */
        struct pollfd pfd[3];
        int out_cnt; /* we buffer a bit of initial CGI output */
        int count;

        /* iobuf is used for CGI -> network data,
         * hdr_buf is for network -> CGI data (POSTDATA) */

        /* If CGI dies, we still want to correctly finish reading its output
         * and send it to the peer. So please no SIGPIPEs! */
        signal(SIGPIPE, SIG_IGN);

        // We inconsistently handle a case when more POSTDATA from network
        // is coming than we expected. We may give *some part* of that
        // extra data to CGI.

        //if (hdr_cnt > post_len) {
        //      /* We got more POSTDATA from network than we expected */
        //      hdr_cnt = post_len;
        //}
        post_len -= hdr_cnt;
        /* post_len - number of POST bytes not yet read from network */

        /* NB: breaking out of this loop jumps to log_and_exit() */
        out_cnt = 0;
        pfd[FROM_CGI].fd = fromCgi_rd;
        pfd[FROM_CGI].events = POLLIN;
        pfd[TO_CGI].fd = toCgi_wr;
        while (1) {
                /* Note: even pfd[0].events == 0 won't prevent
                 * revents == POLLHUP|POLLERR reports from closed stdin.
                 * Setting fd to -1 works: */
                pfd[0].fd = -1;
                pfd[0].events = POLLIN;
                pfd[0].revents = 0; /* probably not needed, paranoia */

                /* We always poll this fd, thus kernel always sets revents: */
                /*pfd[FROM_CGI].events = POLLIN; - moved out of loop */
                /*pfd[FROM_CGI].revents = 0; - not needed */

                /* gcc-4.8.0 still doesnt fill two shorts with one insn :( */
                /* http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47059 */
                /* hopefully one day it will... */
                pfd[TO_CGI].events = POLLOUT;
                pfd[TO_CGI].revents = 0; /* needed! */

                if (toCgi_wr && hdr_cnt <= 0) {
                        if (post_len > 0) {
                                /* Expect more POST data from network */
                                pfd[0].fd = 0;
                        } else {
                                /* post_len <= 0 && hdr_cnt <= 0:
                                 * no more POST data to CGI,
                                 * let CGI see EOF on CGI's stdin */
                                if (toCgi_wr != fromCgi_rd)
                                        close(toCgi_wr);
                                toCgi_wr = 0;
                        }
                }

                /* Now wait on the set of sockets */
                count = safe_poll(pfd, hdr_cnt > 0 ? TO_CGI+1 : FROM_CGI+1, -1);
                if (count <= 0) {
#if 0
                        if (safe_waitpid(pid, &status, WNOHANG) <= 0) {
                                /* Weird. CGI didn't exit and no fd's
                                 * are ready, yet poll returned?! */
                                continue;
                        }
                        if (DEBUG && WIFEXITED(status))
                                bb_error_msg("CGI exited, status=%u", WEXITSTATUS(status));
                        if (DEBUG && WIFSIGNALED(status))
                                bb_error_msg("CGI killed, signal=%u", WTERMSIG(status));
#endif
                        break;
                }

                if (pfd[TO_CGI].revents) {
                        /* hdr_cnt > 0 here due to the way poll() called */
                        /* Have data from peer and can write to CGI */
                        count = safe_write(toCgi_wr, hdr_ptr, hdr_cnt);
                        /* Doesn't happen, we dont use nonblocking IO here
                         *if (count < 0 && errno == EAGAIN) {
                         *      ...
                         *} else */
                        if (count > 0) {
                                hdr_ptr += count;
                                hdr_cnt -= count;
                        } else {
                                /* EOF/broken pipe to CGI, stop piping POST data */
                                hdr_cnt = post_len = 0;
                        }
                }

                if (pfd[0].revents) {
                        /* post_len > 0 && hdr_cnt == 0 here */
                        /* We expect data, prev data portion is eaten by CGI
                         * and there *is* data to read from the peer
                         * (POSTDATA) */
                        //count = post_len > (int)sizeof_hdr_buf ? (int)sizeof_hdr_buf : post_len;
                        //count = safe_read(STDIN_FILENO, hdr_buf, count);
                        count = safe_read(STDIN_FILENO, hdr_buf, sizeof_hdr_buf);
                        if (count > 0) {
                                hdr_cnt = count;
                                hdr_ptr = hdr_buf;
                                post_len -= count;
                        } else {
                                /* no more POST data can be read */
                                post_len = 0;
                        }
                }

                if (pfd[FROM_CGI].revents) {
                        /* There is something to read from CGI */
                        char *rbuf = iobuf;

                        /* Are we still buffering CGI output? */
                        if (out_cnt >= 0) {
                                /* HTTP_200[] has single "\r\n" at the end.
                                 * According to http://hoohoo.ncsa.uiuc.edu/cgi/out.html,
                                 * CGI scripts MUST send their own header terminated by
                                 * empty line, then data. That's why we have only one
                                 * <cr><lf> pair here. We will output "200 OK" line
                                 * if needed, but CGI still has to provide blank line
                                 * between header and body */

                                /* Must use safe_read, not full_read, because
                                 * CGI may output a few first bytes and then wait
                                 * for POSTDATA without closing stdout.
                                 * With full_read we may wait here forever. */
                                count = safe_read(fromCgi_rd, rbuf + out_cnt, IOBUF_SIZE - 8);
                                if (count <= 0) {
                                        /* eof (or error) and there was no "HTTP",
                                         * send "HTTP/1.1 200 OK\r\n", then send received data */
                                        if (out_cnt) {
                                                full_write(STDOUT_FILENO, HTTP_200, sizeof(HTTP_200)-1);
                                                full_write(STDOUT_FILENO, rbuf, out_cnt);
                                        }
                                        break; /* CGI stdout is closed, exiting */
                                }
                                out_cnt += count;
                                count = 0;
                                /* "Status" header format is: "Status: 302 Redirected\r\n" */
                                if (out_cnt >= 8 && memcmp(rbuf, "Status: ", 8) == 0) {
                                        /* send "HTTP/1.1 " */
                                        if (full_write(STDOUT_FILENO, HTTP_200, 9) != 9)
                                                break;
                                        /* skip "Status: " (including space, sending "HTTP/1.1  NNN" is wrong) */
                                        rbuf += 8;
                                        count = out_cnt - 8;
                                        out_cnt = -1; /* buffering off */
                                } else if (out_cnt >= 4) {
                                        /* Did CGI add "HTTP"? */
                                        if (memcmp(rbuf, HTTP_200, 4) != 0) {
                                                /* there is no "HTTP", do it ourself */
                                                if (full_write(STDOUT_FILENO, HTTP_200, sizeof(HTTP_200)-1) != sizeof(HTTP_200)-1)
                                                        break;
                                        }
                                        /* Commented out:
                                        if (!strstr(rbuf, "ontent-")) {
                                                full_write(s, "Content-type: text/plain\r\n\r\n", 28);
                                        }
                                         * Counter-example of valid CGI without Content-type:
                                         * echo -en "HTTP/1.1 302 Found\r\n"
                                         * echo -en "Location: http://www.busybox.net\r\n"
                                         * echo -en "\r\n"
                                         */
                                        count = out_cnt;
                                        out_cnt = -1; /* buffering off */
                                }
                        } else {
                                count = safe_read(fromCgi_rd, rbuf, IOBUF_SIZE);
                                if (count <= 0)
                                        break;  /* eof (or error) */
                        }
                        if (full_write(STDOUT_FILENO, rbuf, count) != count)
                                break;
                        dbg("cgi read %d bytes: '%.*s'\n", count, count, rbuf);
                } /* if (pfd[FROM_CGI].revents) */
        } /* while (1) */
        log_and_exit();
}
#endif

#if ENABLE_FEATURE_HTTPD_CGI

static void setenv1(const char *name, const char *value)
{
        setenv(name, value ? value : "", 1);
}

/*
 * Spawn CGI script, forward CGI's stdin/out <=> network
 *
 * Environment variables are set up and the script is invoked with pipes
 * for stdin/stdout.  If a POST is being done the script is fed the POST
 * data in addition to setting the QUERY_STRING variable (for GETs or POSTs).
 *
 * Parameters:
 * const char *url              The requested URL (with leading /).
 * const char *orig_uri         The original URI before rewriting (if any)
 * int post_len                 Length of the POST body.
 */
static void send_cgi_and_exit(
                const char *url,
                const char *orig_uri,
                const char *request,
                int post_len) NORETURN;
static void send_cgi_and_exit(
                const char *url,
                const char *orig_uri,
                const char *request,
                int post_len)
{
        struct fd_pair fromCgi;  /* CGI -> httpd pipe */
        struct fd_pair toCgi;    /* httpd -> CGI pipe */
        char *script, *last_slash;
        int pid;

        /* Make a copy. NB: caller guarantees:
         * url[0] == '/', url[1] != '/' */
        url = xstrdup(url);

        /*
         * We are mucking with environment _first_ and then vfork/exec,
         * this allows us to use vfork safely. Parent doesn't care about
         * these environment changes anyway.
         */

        /* Check for [dirs/]script.cgi/PATH_INFO */
        last_slash = script = (char*)url;
        while ((script = strchr(script + 1, '/')) != NULL) {
                int dir;
                *script = '\0';
                dir = is_directory(url + 1, /*followlinks:*/ 1);
                *script = '/';
                if (!dir) {
                        /* not directory, found script.cgi/PATH_INFO */
                        break;
                }
                /* is directory, find next '/' */
                last_slash = script;
        }
        setenv1("PATH_INFO", script);   /* set to /PATH_INFO or "" */
        setenv1("REQUEST_METHOD", request);
        if (g_query) {
                putenv(xasprintf("%s=%s?%s", "REQUEST_URI", orig_uri, g_query));
        } else {
                setenv1("REQUEST_URI", orig_uri);
        }
        if (script != NULL)
                *script = '\0';         /* cut off /PATH_INFO */

        /* SCRIPT_FILENAME is required by PHP in CGI mode */
        if (home_httpd[0] == '/') {
                char *fullpath = concat_path_file(home_httpd, url);
                setenv1("SCRIPT_FILENAME", fullpath);
        }
        /* set SCRIPT_NAME as full path: /cgi-bin/dirs/script.cgi */
        setenv1("SCRIPT_NAME", url);
        /* http://hoohoo.ncsa.uiuc.edu/cgi/env.html:
         * QUERY_STRING: The information which follows the ? in the URL
         * which referenced this script. This is the query information.
         * It should not be decoded in any fashion. This variable
         * should always be set when there is query information,
         * regardless of command line decoding. */
        /* (Older versions of bbox seem to do some decoding) */
        setenv1("QUERY_STRING", g_query);
        putenv((char*)"SERVER_SOFTWARE=busybox httpd/"BB_VER);
        putenv((char*)"SERVER_PROTOCOL=HTTP/1.1");
        putenv((char*)"GATEWAY_INTERFACE=CGI/1.1");
        /* Having _separate_ variables for IP and port defeats
         * the purpose of having socket abstraction. Which "port"
         * are you using on Unix domain socket?
         * IOW - REMOTE_PEER="1.2.3.4:56" makes much more sense.
         * Oh well... */
        {
                char *p = rmt_ip_str ? rmt_ip_str : (char*)"";
                char *cp = strrchr(p, ':');
                if (ENABLE_FEATURE_IPV6 && cp && strchr(cp, ']'))
                        cp = NULL;
                if (cp) *cp = '\0'; /* delete :PORT */
                setenv1("REMOTE_ADDR", p);
                if (cp) {
                        *cp = ':';
#if ENABLE_FEATURE_HTTPD_SET_REMOTE_PORT_TO_ENV
                        setenv1("REMOTE_PORT", cp + 1);
#endif
                }
        }
        if (post_len)
                putenv(xasprintf("CONTENT_LENGTH=%u", post_len));
#if ENABLE_FEATURE_HTTPD_BASIC_AUTH
        if (remoteuser) {
                setenv1("REMOTE_USER", remoteuser);
                putenv((char*)"AUTH_TYPE=Basic");
        }
#endif
        /* setenv1("SERVER_NAME", safe_gethostname()); - don't do this,
         * just run "env SERVER_NAME=xyz httpd ..." instead */

        xpiped_pair(fromCgi);
        xpiped_pair(toCgi);

        pid = vfork();
        if (pid < 0) {
                /* TODO: log perror? */
                log_and_exit();
        }

        if (pid == 0) {
                /* Child process */
                char *argv[3];

                xfunc_error_retval = 242;

                /* NB: close _first_, then move fds! */
                close(toCgi.wr);
                close(fromCgi.rd);
                xmove_fd(toCgi.rd, 0);  /* replace stdin with the pipe */
                xmove_fd(fromCgi.wr, 1);  /* replace stdout with the pipe */
                /* User seeing stderr output can be a security problem.
                 * If CGI really wants that, it can always do dup itself. */
                /* dup2(1, 2); */

                /* Chdiring to script's dir */
                script = last_slash;
                if (script != url) { /* paranoia */
                        *script = '\0';
                        if (chdir(url + 1) != 0) {
                                bb_perror_msg("can't change directory to '%s'", url + 1);
                                goto error_execing_cgi;
                        }
                        // not needed: *script = '/';
                }
                script++;

                /* set argv[0] to name without path */
                argv[0] = script;
                argv[1] = NULL;

#if ENABLE_FEATURE_HTTPD_CONFIG_WITH_SCRIPT_INTERPR
                {
                        char *suffix = strrchr(script, '.');

                        if (suffix) {
                                Htaccess *cur;
                                for (cur = script_i; cur; cur = cur->next) {
                                        if (strcmp(cur->before_colon + 1, suffix) == 0) {
                                                /* found interpreter name */
                                                argv[0] = cur->after_colon;
                                                argv[1] = script;
                                                argv[2] = NULL;
                                                break;
                                        }
                                }
                        }
                }
#endif
                /* restore default signal dispositions for CGI process */
                bb_signals(0
                        | (1 << SIGCHLD)
                        | (1 << SIGPIPE)
                        | (1 << SIGHUP)
                        , SIG_DFL);

                /* _NOT_ execvp. We do not search PATH. argv[0] is a filename
                 * without any dir components and will only match a file
                 * in the current directory */
                execv(argv[0], argv);
                if (verbose)
                        bb_perror_msg("can't execute '%s'", argv[0]);
 error_execing_cgi:
                /* send to stdout
                 * (we are CGI here, our stdout is pumped to the net) */
                send_headers_and_exit(HTTP_NOT_FOUND);
        } /* end child */

        /* Parent process */

        /* Restore variables possibly changed by child */
        xfunc_error_retval = 0;

        /* Pump data */
        close(fromCgi.wr);
        close(toCgi.rd);
        cgi_io_loop_and_exit(fromCgi.rd, toCgi.wr, post_len);
}

#endif          /* FEATURE_HTTPD_CGI */

/*
 * Send a file response to a HTTP request, and exit
 *
 * Parameters:
 * const char *url  The requested URL (with leading /).
 * what             What to send (headers/body/both).
 */
static NOINLINE void send_file_and_exit(const char *url, int what)
{
        char *suffix;
        int fd;
        ssize_t count;

        if (content_gzip) {
                /* does <url>.gz exist? Then use it instead */
                char *gzurl = xasprintf("%s.gz", url);
                fd = open(gzurl, O_RDONLY);
                free(gzurl);
                if (fd != -1) {
                        struct stat sb;
                        fstat(fd, &sb);
                        file_size = sb.st_size;
                        last_mod = sb.st_mtime;
                } else {
                        IF_FEATURE_HTTPD_GZIP(content_gzip = 0;)
                        fd = open(url, O_RDONLY);
                }
        } else {
                fd = open(url, O_RDONLY);
                /* file_size and last_mod are already populated */
        }
        if (fd < 0) {
                dbg("can't open '%s'\n", url);
                /* Error pages are sent by using send_file_and_exit(SEND_BODY).
                 * IOW: it is unsafe to call send_headers_and_exit
                 * if what is SEND_BODY! Can recurse! */
                if (what != SEND_BODY)
                        send_headers_and_exit(HTTP_NOT_FOUND);
                log_and_exit();
        }
#if ENABLE_FEATURE_HTTPD_ETAG
        /* ETag is "hex(last_mod)-hex(file_size)" e.g. "5e132e20-417" */
        sprintf(G.etag, "\"%llx-%llx\"", (unsigned long long)last_mod, (unsigned long long)file_size);

        if (G.if_none_match) {
                dbg("If-None-Match:'%s' file's ETag:'%s'\n", G.if_none_match, G.etag);
                /* Weak ETag comparision.
                 * If-None-Match may have many ETags but they are quoted so we can use simple substring search */
                if (strstr(G.if_none_match, G.etag))
                        send_headers_and_exit(HTTP_NOT_MODIFIED);
        }
#endif
        /* If you want to know about EPIPE below
         * (happens if you abort downloads from local httpd): */
        signal(SIGPIPE, SIG_IGN);

        /* If not found, default is to not send "Content-type:" */
        /*found_mime_type = NULL; - already is */
        suffix = strrchr(url, '.');
        if (suffix) {
                static const char suffixTable[] ALIGN1 =
                        /* Shorter suffix must be first:
                         * ".html.htm" will fail for ".htm"
                         */
                        ".txt.h.c.cc.cpp\0" "text/plain\0"
                        /* .htm line must be after .h line */
                        ".htm.html\0" "text/html\0"
                        ".jpg.jpeg\0" "image/jpeg\0"
                        ".gif\0"      "image/gif\0"
                        ".png\0"      "image/png\0"
                        ".svg\0"      "image/svg+xml\0"
                        /* .css line must be after .c line */
                        ".css\0"      "text/css\0"
                        ".js\0"       "application/javascript\0"
                        ".wav\0"      "audio/wav\0"
                        ".avi\0"      "video/x-msvideo\0"
                        ".qt.mov\0"   "video/quicktime\0"
                        ".mpe.mpeg\0" "video/mpeg\0"
                        ".mid.midi\0" "audio/midi\0"
                        ".mp3\0"      "audio/mpeg\0"
#if 0  /* unpopular */
                        ".au\0"       "audio/basic\0"
                        ".pac\0"      "application/x-ns-proxy-autoconfig\0"
                        ".vrml.wrl\0" "model/vrml\0"
#endif
                        /* compiler adds another "\0" here */
                ;
                Htaccess *cur;

                /* Examine built-in table */
                const char *table = suffixTable;
                const char *table_next;
                for (; *table; table = table_next) {
                        const char *try_suffix;
                        const char *mime_type;
                        mime_type  = table + strlen(table) + 1;
                        table_next = mime_type + strlen(mime_type) + 1;
                        try_suffix = strstr(table, suffix);
                        if (!try_suffix)
                                continue;
                        try_suffix += strlen(suffix);
                        if (*try_suffix == '\0' || *try_suffix == '.') {
                                found_mime_type = mime_type;
                                break;
                        }
                        /* Example: strstr(table, ".av") != NULL, but it
                         * does not match ".avi" after all and we end up here.
                         * The table is arranged so that in this case we know
                         * that it can't match anything in the following lines,
                         * and we stop the search: */
                        break;
                }
                /* ...then user's table */
                for (cur = mime_a; cur; cur = cur->next) {
                        if (strcmp(cur->before_colon, suffix) == 0) {
                                found_mime_type = cur->after_colon;
                                break;
                        }
                }
        }

        dbg("sending file '%s' content-type:%s\n", url, found_mime_type);

#if ENABLE_FEATURE_HTTPD_RANGES
        if (what == SEND_BODY /* err pages and ranges don't mix */
         || content_gzip /* we are sending compressed page: can't do ranges */  ///why?
        ) {
                range_start = -1;
        }
        range_len = MAXINT(off_t);
        if (range_start >= 0) {
                if (!range_end || range_end > file_size - 1) {
                        range_end = file_size - 1;
                }
                if (range_end < range_start
                 || lseek(fd, range_start, SEEK_SET) != range_start
                ) {
                        lseek(fd, 0, SEEK_SET);
                        range_start = -1;
                } else {
                        range_len = range_end - range_start + 1;
                        send_headers(HTTP_PARTIAL_CONTENT);
                        what = SEND_BODY;
                }
        }
#endif
        if (what & SEND_HEADERS)
                send_headers(HTTP_OK);
#if ENABLE_FEATURE_USE_SENDFILE
        {
                off_t offset;
# if ENABLE_FEATURE_HTTPD_RANGES
                if (range_start < 0)
                        range_start = 0;
                offset = range_start;
# else
                offset = 0;
# endif
                while (1) {
                        /* sz is rounded down to 64k */
                        ssize_t sz = MAXINT(ssize_t) - 0xffff;
                        IF_FEATURE_HTTPD_RANGES(if (sz > range_len) sz = range_len;)
                        count = sendfile(STDOUT_FILENO, fd, &offset, sz);
                        if (count < 0) {
                                if (offset == range_start) /* was it the very 1st sendfile? */
                                        break; /* fall back to read/write loop */
                                goto fin;
                        }
                        IF_FEATURE_HTTPD_RANGES(range_len -= count;)
                        if (count == 0 || range_len == 0)
                                log_and_exit();
                }
        }
#endif
        while ((count = safe_read(fd, iobuf, IOBUF_SIZE)) > 0) {
                ssize_t n;
                IF_FEATURE_HTTPD_RANGES(if (count > range_len) count = range_len;)
                n = full_write(STDOUT_FILENO, iobuf, count);
                if (count != n)
                        break;
                IF_FEATURE_HTTPD_RANGES(range_len -= count;)
                if (range_len == 0)
                        break;
        }
        if (count < 0) {
 IF_FEATURE_USE_SENDFILE(fin:)
                if (verbose > 1)
                        bb_simple_perror_msg("error");
        }
        log_and_exit();
}

#if ENABLE_FEATURE_HTTPD_ACL_IP
static void if_ip_denied_send_HTTP_FORBIDDEN_and_exit(unsigned remote_ip)
{
        Htaccess_IP *cur;

        for (cur = G.ip_a_d; cur; cur = cur->next) {
                dbg("checkPermIP: '%s' ? '%u.%u.%u.%u/%u.%u.%u.%u'\n",
                        rmt_ip_str,
                        (unsigned char)(cur->ip >> 24),
                        (unsigned char)(cur->ip >> 16),
                        (unsigned char)(cur->ip >> 8),
                        (unsigned char)(cur->ip),
                        (unsigned char)(cur->mask >> 24),
                        (unsigned char)(cur->mask >> 16),
                        (unsigned char)(cur->mask >> 8),
                        (unsigned char)(cur->mask)
                );
                if ((remote_ip & cur->mask) == cur->ip) {
                        if (cur->allow_deny == 'A')
                                return;
                        send_headers_and_exit(HTTP_FORBIDDEN);
                }
        }

        if (flg_deny_all) /* depends on whether we saw "D:*" */
                send_headers_and_exit(HTTP_FORBIDDEN);
}
#else
# define if_ip_denied_send_HTTP_FORBIDDEN_and_exit(arg) ((void)0)
#endif

#if ENABLE_FEATURE_HTTPD_BASIC_AUTH

# if ENABLE_PAM
struct pam_userinfo {
        const char *name;
        const char *pw;
};

static int pam_talker(int num_msg,
                const struct pam_message **msg,
                struct pam_response **resp,
                void *appdata_ptr)
{
        int i;
        struct pam_userinfo *userinfo = (struct pam_userinfo *) appdata_ptr;
        struct pam_response *response;

        if (!resp || !msg || !userinfo)
                return PAM_CONV_ERR;

        /* allocate memory to store response */
        response = xzalloc(num_msg * sizeof(*response));

        /* copy values */
        for (i = 0; i < num_msg; i++) {
                const char *s;

                switch (msg[i]->msg_style) {
                case PAM_PROMPT_ECHO_ON:
                        s = userinfo->name;
                        break;
                case PAM_PROMPT_ECHO_OFF:
                        s = userinfo->pw;
                        break;
                case PAM_ERROR_MSG:
                case PAM_TEXT_INFO:
                        s = "";
                        break;
                default:
                        free(response);
                        return PAM_CONV_ERR;
                }
                response[i].resp = xstrdup(s);
                if (PAM_SUCCESS != 0)
                        response[i].resp_retcode = PAM_SUCCESS;
        }

        *resp = response;
        return PAM_SUCCESS;
}
# endif

/*
 * Config file entries are of the form "/<path>:<user>:<passwd>".
 * If config file has no prefix match for path, access is allowed.
 *
 * path                 The file path
 * user_and_passwd      "user:passwd" to validate
 *
 * Returns 1 if user_and_passwd is OK.
 */
static int check_user_passwd(const char *path, char *user_and_passwd)
{
        Htaccess *cur;
        const char *prev = NULL;

        for (cur = g_auth; cur; cur = cur->next) {
                const char *dir_prefix;
                size_t len;
                int r;

                dir_prefix = cur->before_colon;

                /* WHY? */
                /* If already saw a match, don't accept other different matches */
                if (prev && strcmp(prev, dir_prefix) != 0)
                        continue;

                dbg("checkPerm: '%s' ? '%s'\n", dir_prefix, user_and_passwd);

                /* If it's not a prefix match, continue searching */
                len = strlen(dir_prefix);
                if (len != 1 /* dir_prefix "/" matches all, don't need to check */
                 && (strncmp(dir_prefix, path, len) != 0
                    || (path[len] != '/' && path[len] != '\0')
                    )
                ) {
                        continue;
                }

                /* Path match found */
                prev = dir_prefix;

                if (ENABLE_FEATURE_HTTPD_AUTH_MD5) {
                        char *colon_after_user;
                        const char *passwd;
# if ENABLE_FEATURE_SHADOWPASSWDS && !ENABLE_PAM
                        char sp_buf[256];
# endif

                        colon_after_user = strchr(user_and_passwd, ':');
                        if (!colon_after_user)
                                goto bad_input;

                        /* compare "user:" */
                        if (cur->after_colon[0] != '*'
                         && strncmp(cur->after_colon, user_and_passwd,
                                        colon_after_user - user_and_passwd + 1) != 0
                        ) {
                                continue;
                        }
                        /* this cfg entry is '*' or matches username from peer */

                        passwd = strchr(cur->after_colon, ':');
                        if (!passwd)
                                goto bad_input;
                        passwd++;
                        if (passwd[0] == '*') {
# if ENABLE_PAM
                                struct pam_userinfo userinfo;
                                struct pam_conv conv_info = { &pam_talker, (void *) &userinfo };
                                pam_handle_t *pamh;

                                *colon_after_user = '\0';
                                userinfo.name = user_and_passwd;
                                userinfo.pw = colon_after_user + 1;
                                r = pam_start("httpd", user_and_passwd, &conv_info, &pamh) != PAM_SUCCESS;
                                if (r == 0) {
                                        r = pam_authenticate(pamh, PAM_DISALLOW_NULL_AUTHTOK) != PAM_SUCCESS
                                         || pam_acct_mgmt(pamh, PAM_DISALLOW_NULL_AUTHTOK)    != PAM_SUCCESS
                                        ;
                                        pam_end(pamh, PAM_SUCCESS);
                                }
                                *colon_after_user = ':';
                                goto end_check_passwd;
# else
#  if ENABLE_FEATURE_SHADOWPASSWDS
                                /* Using _r function to avoid pulling in static buffers */
                                struct spwd spw;
#  endif
                                struct passwd *pw;

                                *colon_after_user = '\0';
                                pw = getpwnam(user_and_passwd);
                                *colon_after_user = ':';
                                if (!pw || !pw->pw_passwd)
                                        continue;
                                passwd = pw->pw_passwd;
#  if ENABLE_FEATURE_SHADOWPASSWDS
                                if ((passwd[0] == 'x' || passwd[0] == '*') && !passwd[1]) {
                                        /* getspnam_r may return 0 yet set result to NULL.
                                         * At least glibc 2.4 does this. Be extra paranoid here. */
                                        struct spwd *result = NULL;
                                        r = getspnam_r(pw->pw_name, &spw, sp_buf, sizeof(sp_buf), &result);
                                        if (r == 0 && result)
                                                passwd = result->sp_pwdp;
                                }
#  endif
                                /* In this case, passwd is ALWAYS encrypted:
                                 * it came from /etc/passwd or /etc/shadow!
                                 */
                                goto check_encrypted;
# endif /* ENABLE_PAM */
                        }
                        /* Else: passwd is from httpd.conf, it is either plaintext or encrypted */

                        if (passwd[0] == '$' && isdigit(passwd[1])) {
                                char *encrypted;
# if !ENABLE_PAM
 check_encrypted:
# endif
                                /* encrypt pwd from peer and check match with local one */
                                encrypted = pw_encrypt(
                                        /* pwd (from peer): */  colon_after_user + 1,
                                        /* salt: */ passwd,
                                        /* cleanup: */ 0
                                );
                                r = strcmp(encrypted, passwd);
                                free(encrypted);
                        } else {
                                /* local passwd is from httpd.conf and it's plaintext */
                                r = strcmp(colon_after_user + 1, passwd);
                        }
                        goto end_check_passwd;
                }
 bad_input:
                /* Comparing plaintext "user:pass" in one go */
                r = strcmp(cur->after_colon, user_and_passwd);
 end_check_passwd:
                if (r == 0) {
                        remoteuser = xstrndup(user_and_passwd,
                                strchrnul(user_and_passwd, ':') - user_and_passwd
                        );
                        return 1; /* Ok */
                }
        } /* for */

        /* 0(bad) if prev is set: matches were found but passwd was wrong */
        return (prev == NULL);
}
#endif  /* FEATURE_HTTPD_BASIC_AUTH */

#if ENABLE_FEATURE_HTTPD_PROXY
static Htaccess_Proxy *find_proxy_entry(const char *url)
{
        Htaccess_Proxy *p;
        for (p = proxy; p; p = p->next) {
                if (is_prefixed_with(url, p->url_from))
                        return p;
        }
        return NULL;
}
#endif

/*
 * Handle timeouts
 */
static void send_REQUEST_TIMEOUT_and_exit(int sig) NORETURN;
static void send_REQUEST_TIMEOUT_and_exit(int sig UNUSED_PARAM)
{
        send_headers_and_exit(HTTP_REQUEST_TIMEOUT);
}

/*
 * Handle an incoming http request and exit.
 */
static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr) NORETURN;
static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr)
{
        struct stat sb;
        char *urlcopy;
        char *urlp;
        char *tptr;
#if ENABLE_FEATURE_HTTPD_ACL_IP
        unsigned remote_ip;
#endif
#if ENABLE_FEATURE_HTTPD_CGI
        unsigned total_headers_len;
#endif
        const char *prequest;
        static const char request_GET[]  ALIGN1 = "GET";
        static const char request_HEAD[] ALIGN1 = "HEAD";
#if ENABLE_FEATURE_HTTPD_CGI
        static const char request_POST[] ALIGN1 = "POST";
        unsigned long POST_length;
        enum CGI_type {
                CGI_NONE = 0,
                CGI_NORMAL,
                CGI_INDEX,
                CGI_INTERPRETER,
        } cgi_type = CGI_NONE;
#endif
#if ENABLE_FEATURE_HTTPD_PROXY
        Htaccess_Proxy *proxy_entry;
#endif
#if ENABLE_FEATURE_HTTPD_BASIC_AUTH
        smallint authorized = -1;
#endif
        char *HTTP_slash;

        /* Allocation of iobuf is postponed until now
         * (IOW, server process doesn't need to waste 8k) */
        iobuf = xmalloc(IOBUF_SIZE);

        if (ENABLE_FEATURE_HTTPD_CGI || DEBUG || verbose) {
                /* NB: can be NULL (user runs httpd -i by hand?) */
                rmt_ip_str = xmalloc_sockaddr2dotted(&fromAddr->u.sa);
        }
        if (verbose) {
                /* this trick makes -v logging much simpler */
                if (rmt_ip_str)
                        applet_name = rmt_ip_str;
                if (verbose > 2)
                        bb_simple_error_msg("connected");
        }
#if ENABLE_FEATURE_HTTPD_ACL_IP
        remote_ip = 0;
        if (fromAddr->u.sa.sa_family == AF_INET) {
                remote_ip = ntohl(fromAddr->u.sin.sin_addr.s_addr);
        }
# if ENABLE_FEATURE_IPV6
        if (fromAddr->u.sa.sa_family == AF_INET6
         && fromAddr->u.sin6.sin6_addr.s6_addr32[0] == 0
         && fromAddr->u.sin6.sin6_addr.s6_addr32[1] == 0
         && ntohl(fromAddr->u.sin6.sin6_addr.s6_addr32[2]) == 0xffff)
                remote_ip = ntohl(fromAddr->u.sin6.sin6_addr.s6_addr32[3]);
# endif
        if_ip_denied_send_HTTP_FORBIDDEN_and_exit(remote_ip);
#endif

        /* Install timeout handler. get_line() needs it. */
        signal(SIGALRM, send_REQUEST_TIMEOUT_and_exit);

        if (!get_line()) { /* EOF or error or empty line */
                /* Observed Firefox to "speculatively" open
                 * extra connections to a new site on first access,
                 * they are closed in ~5 seconds with nothing
                 * being sent at all.
                 * (Presumably it's a method to decrease latency?)
                 */
                if (verbose > 2)
                        bb_simple_error_msg("eof on read, closing");
                /* Don't bother generating error page in this case,
                 * just close the socket.
                 */
                //send_headers_and_exit(HTTP_BAD_REQUEST);
                _exit(xfunc_error_retval);
        }
        dbg("Request:'%s'\n", iobuf);

        /* Find URL */
        // rfc2616: method and URI is separated by exactly one space
        //urlp = strpbrk(iobuf, " \t"); - no, tab isn't allowed
        urlp = strchr(iobuf, ' ');
        if (urlp == NULL)
                send_headers_and_exit(HTTP_BAD_REQUEST);
        *urlp++ = '\0';
        //urlp = skip_whitespace(urlp); - should not be necessary
        if (urlp[0] != '/')
                send_headers_and_exit(HTTP_BAD_REQUEST);
        /* Find end of URL */
        HTTP_slash = strchr(urlp, ' ');
        /* Is it " HTTP/"? */
        if (!HTTP_slash || strncmp(HTTP_slash + 1, HTTP_200, 5) != 0)
                send_headers_and_exit(HTTP_BAD_REQUEST);
        *HTTP_slash++ = '\0';

#if ENABLE_FEATURE_HTTPD_PROXY
        proxy_entry = find_proxy_entry(urlp);
        if (proxy_entry) {
                int proxy_fd;
                len_and_sockaddr *lsa;

                if (verbose > 1)
                        bb_error_msg("proxy:%s", urlp);
                lsa = host2sockaddr(proxy_entry->host_port, 80);
                if (!lsa)
                        send_headers_and_exit(HTTP_INTERNAL_SERVER_ERROR);
                proxy_fd = socket(lsa->u.sa.sa_family, SOCK_STREAM, 0);
                if (proxy_fd < 0)
                        send_headers_and_exit(HTTP_INTERNAL_SERVER_ERROR);
                if (connect(proxy_fd, &lsa->u.sa, lsa->len) < 0)
                        send_headers_and_exit(HTTP_INTERNAL_SERVER_ERROR);
                /* Disable peer header reading timeout */
                alarm(0);
                /* Config directive was of the form:
                 *   P:/url:[http://]hostname[:port]/new/path
                 * When /urlSFX is requested, reverse proxy it
                 * to http://hostname[:port]/new/pathSFX
                 */
                fdprintf(proxy_fd, "%s %s%s %s\r\n",
                                iobuf, /* "GET" / "POST" / etc */
                                proxy_entry->url_to, /* "/new/path" */
                                urlp + strlen(proxy_entry->url_from), /* "SFX" */
                                HTTP_slash /* "HTTP/xyz" */
                );
                cgi_io_loop_and_exit(proxy_fd, proxy_fd, /*max POST length:*/ INT_MAX);
        }
#endif

        /* Determine type of request (GET/POST/...) */
        prequest = request_GET;
        if (strcasecmp(iobuf, prequest) == 0)
                goto found;
        prequest = request_HEAD;
        if (strcasecmp(iobuf, prequest) == 0)
                goto found;
#if !ENABLE_FEATURE_HTTPD_CGI
        send_headers_and_exit(HTTP_NOT_IMPLEMENTED);
#else
        prequest = request_POST;
        if (strcasecmp(iobuf, prequest) == 0)
                goto found;
        /* For CGI, allow DELETE, PUT, OPTIONS, etc too */
        prequest = alloca(16);
        safe_strncpy((char*)prequest, iobuf, 16);
#endif
 found:
        /* Copy URL to stack-allocated char[] */
        urlcopy = alloca((HTTP_slash - urlp) + 2 + strlen(index_page));
        strcpy(urlcopy, urlp);
        /* NB: urlcopy ptr is never changed after this */

        /* Extract url args if present */
        g_query = strchr(urlcopy, '?');
        if (g_query)
                *g_query++ = '\0';

        /* Decode URL escape sequences */
        tptr = percent_decode_in_place(urlcopy, /*strict:*/ 1);
        if (tptr == NULL)
                send_headers_and_exit(HTTP_BAD_REQUEST);
        if (tptr == urlcopy + 1) {
                /* '/' or NUL is encoded */
                send_headers_and_exit(HTTP_NOT_FOUND);
        }

        /* Canonicalize path */
        /* Algorithm stolen from libbb bb_simplify_path(),
         * but don't strdup, retain trailing slash, protect root */
        urlp = tptr = urlcopy;
        while (1) {
                if (*urlp == '/') {
                        /* skip duplicate (or initial) slash */
                        if (*tptr == '/') {
                                goto next_char;
                        }
                        if (*tptr == '.') {
                                if (tptr[1] == '.' && (tptr[2] == '/' || tptr[2] == '\0')) {
                                        /* "..": be careful */
                                        /* protect root */
                                        if (urlp == urlcopy)
                                                send_headers_and_exit(HTTP_BAD_REQUEST);
                                        /* omit previous dir */
                                        while (*--urlp != '/')
                                                continue;
                                        /* skip to "./" or ".<NUL>" */
                                        tptr++;
                                }
                                if (tptr[1] == '/' || tptr[1] == '\0') {
                                        /* skip extra "/./" */
                                        goto next_char;
                                }
                        }
                }
                *++urlp = *tptr;
                if (*tptr == '\0')
                        break;
 next_char:
                tptr++;
        }

        /* Log it */
        if (verbose > 1)
                bb_error_msg("url:%s", urlcopy);

        tptr = urlcopy;
        while ((tptr = strchr(tptr + 1, '/')) != NULL) {
                /* have path1/path2 */
                *tptr = '\0';
                /* may have subdir config */
                if (parse_conf(urlcopy + 1, SUBDIR_PARSE) == 0)
                        if_ip_denied_send_HTTP_FORBIDDEN_and_exit(remote_ip);
                *tptr = '/';
        }

        tptr = urlcopy + 1;      /* skip first '/' */

#if ENABLE_FEATURE_HTTPD_CGI
        if (is_prefixed_with(tptr, "cgi-bin/")) {
                if (tptr[8] == '\0') {
                        /* protect listing "cgi-bin/" */
                        send_headers_and_exit(HTTP_FORBIDDEN);
                }
                cgi_type = CGI_NORMAL;
        }
#endif

        if (urlp[-1] == '/') {
                /* When index_page string is appended to <dir>/ URL, it overwrites
                 * the query string. If we fall back to call /cgi-bin/index.cgi,
                 * query string would be lost and not available to the CGI.
                 * Work around it by making a deep copy.
                 */
                if (ENABLE_FEATURE_HTTPD_CGI)
                        g_query = xstrdup(g_query); /* ok for NULL too */
                strcpy(urlp, index_page);
        }
        if (stat(tptr, &sb) == 0) {
                /* If URL is a directory with no slash, set up
                 * "HTTP/1.1 302 Found" "Location: /dir/" reply */
                if (urlp[-1] != '/' && S_ISDIR(sb.st_mode)) {
                        found_moved_temporarily = urlcopy;
                } else {
#if ENABLE_FEATURE_HTTPD_CONFIG_WITH_SCRIPT_INTERPR
                        char *suffix = strrchr(tptr, '.');
                        if (suffix) {
                                Htaccess *cur;
                                for (cur = script_i; cur; cur = cur->next) {
                                        if (strcmp(cur->before_colon + 1, suffix) == 0) {
                                                cgi_type = CGI_INTERPRETER;
                                                break;
                                        }
                                }
                        }
#endif
                        file_size = sb.st_size;
                        last_mod = sb.st_mtime;
                }
        }
#if ENABLE_FEATURE_HTTPD_CGI
        else if (urlp[-1] == '/') {
                /* It's a dir URL and there is no index.html */
                /* Is there cgi-bin/index.cgi? */
                if (access("/cgi-bin/index.cgi"+1, X_OK) != 0)
                        send_headers_and_exit(HTTP_NOT_FOUND); /* no */
                cgi_type = CGI_INDEX;
        }
#endif

#if ENABLE_FEATURE_HTTPD_BASIC_AUTH || ENABLE_FEATURE_HTTPD_CGI
        /* check_user_passwd() would be confused by added .../index.html, truncate it */
        urlp[0] = '\0';
#endif

#if ENABLE_FEATURE_HTTPD_CGI
        total_headers_len = 0;
        POST_length = 0;
#endif

        /* Read until blank line */
        while (1) {
                unsigned iobuf_len = get_line();
                if (!iobuf_len)
                        break; /* EOF or error or empty line */
#if ENABLE_FEATURE_HTTPD_CGI
                /* Prevent unlimited growth of HTTP_xyz envvars */
                total_headers_len += iobuf_len;
                if (total_headers_len >= MAX_HTTP_HEADERS_SIZE)
                        send_headers_and_exit(HTTP_ENTITY_TOO_LARGE);
#endif
                dbg("header:'%s'\n", iobuf);
#if ENABLE_FEATURE_HTTPD_CGI
                /* Only POST needs to know POST_length */
                if (prequest == request_POST && STRNCASECMP(iobuf, "Content-Length:") == 0) {
                        tptr = skip_whitespace(iobuf + sizeof("Content-Length:") - 1);
                        if (!tptr[0])
                                send_headers_and_exit(HTTP_BAD_REQUEST);
                        /* not using strtoul: it ignores leading minus! */
                        POST_length = bb_strtou(tptr, NULL, 10);
                        /* length is "ulong", but we need to pass it to int later */
                        if (errno || POST_length > INT_MAX)
                                send_headers_and_exit(HTTP_BAD_REQUEST);
                        continue;
                }
#endif
#if ENABLE_FEATURE_HTTPD_BASIC_AUTH
                if (STRNCASECMP(iobuf, "Authorization:") == 0) {
                        /* We only allow Basic credentials.
                         * It shows up as "Authorization: Basic <user>:<passwd>" where
                         * "<user>:<passwd>" is base64 encoded.
                         */
                        tptr = skip_whitespace(iobuf + sizeof("Authorization:")-1);
                        if (STRNCASECMP(tptr, "Basic") == 0) {
                                tptr += sizeof("Basic")-1;
                                /* decodeBase64() skips whitespace itself */
                                decodeBase64(tptr);
                                authorized = check_user_passwd(urlcopy, tptr);
                                continue;
                        }
                }
#endif
#if ENABLE_FEATURE_HTTPD_RANGES
                if (STRNCASECMP(iobuf, "Range:") == 0) {
                        /* We know only bytes=NNN-[MMM] */
                        char *s = skip_whitespace(iobuf + sizeof("Range:")-1);
                        s = is_prefixed_with(s, "bytes=");
                        if (s) {
                                range_start = BB_STRTOOFF(s, &s, 10);
                                if (s[0] != '-' || range_start < 0) {
                                        range_start = -1;
                                } else if (s[1]) {
                                        range_end = BB_STRTOOFF(s+1, NULL, 10);
                                        if (errno || range_end < range_start)
                                                range_start = -1;
                                }
                        }
                        continue;
                }
#endif
#if ENABLE_FEATURE_HTTPD_GZIP
                if (STRNCASECMP(iobuf, "Accept-Encoding:") == 0) {
                        /* Note: we do not support "gzip;q=0"
                         * method of _disabling_ gzip
                         * delivery. No one uses that, though */
                        const char *s = strstr(iobuf, "gzip");
                        if (s) {
                                // want more thorough checks?
                                //if (s[-1] == ' '
                                // || s[-1] == ','
                                // || s[-1] == ':'
                                //) {
                                        content_gzip = 1;
                                //}
                        }
                        continue;
                }
#endif
#if ENABLE_FEATURE_HTTPD_ETAG
                if (STRNCASECMP(iobuf, "If-None-Match:") == 0) {
                        free(G.if_none_match);
                        G.if_none_match = xstrdup(skip_whitespace(iobuf + sizeof("If-None-Match:") - 1));
                        continue;
                }
#endif
#if ENABLE_FEATURE_HTTPD_CGI
                if (cgi_type != CGI_NONE) {
                        bool ct = (STRNCASECMP(iobuf, "Content-Type:") == 0);
                        char *cp;
                        char *colon = strchr(iobuf, ':');

                        if (!colon)
                                continue;
                        cp = iobuf;
                        while (cp < colon) {
                                /* a-z => A-Z, not-alnum => _ */
                                char c = (*cp & ~0x20); /* toupper for A-Za-z, undef for others */
                                if ((unsigned)(c - 'A') <= ('Z' - 'A')) {
                                        *cp++ = c;
                                        continue;
                                }
                                if (!isdigit(*cp))
                                        *cp = '_';
                                cp++;
                        }
                        /* "Content-Type:" gets no HTTP_ prefix, all others do */
                        cp = xasprintf(ct ? "HTTP_%.*s=%s" + 5 : "HTTP_%.*s=%s",
                                (int)(colon - iobuf), iobuf,
                                skip_whitespace(colon + 1)
                        );
                        putenv(cp);
                }
#endif
        } /* while extra header reading */

        /* We are done reading headers, disable peer timeout */
        alarm(0);

        if (strcmp(bb_basename(urlcopy), HTTPD_CONF) == 0) {
                /* protect listing [/path]/httpd.conf or IP deny */
                send_headers_and_exit(HTTP_FORBIDDEN);
        }

#if ENABLE_FEATURE_HTTPD_BASIC_AUTH
        /* Case: no "Authorization:" was seen, but page might require passwd.
         * Check that with dummy user:pass */
        if (authorized < 0)
                authorized = check_user_passwd(urlcopy, (char *) "");
        if (!authorized)
                send_headers_and_exit(HTTP_UNAUTHORIZED);
#endif

        if (found_moved_temporarily)
                send_headers_and_exit(HTTP_MOVED_TEMPORARILY);

#if ENABLE_FEATURE_HTTPD_CGI
        if (cgi_type != CGI_NONE) {
                send_cgi_and_exit(
                        (cgi_type == CGI_INDEX) ? "/cgi-bin/index.cgi"
                        /*CGI_NORMAL or CGI_INTERPRETER*/ : urlcopy,
                        urlcopy, prequest, POST_length
                );
        }
#endif

#if ENABLE_FEATURE_HTTPD_CGI
        if (prequest != request_GET && prequest != request_HEAD) {
                /* POST / DELETE / PUT / OPTIONS for files do not make sense */
                send_headers_and_exit(HTTP_NOT_IMPLEMENTED);
        }
#else
        /* !CGI: it can be only GET or HEAD */
#endif

#if ENABLE_FEATURE_HTTPD_BASIC_AUTH
        /* Restore truncated .../index.html */
        if (urlp[-1] == '/')
                urlp[0] = index_page[0];
#endif
        send_file_and_exit(urlcopy + 1,
                (prequest != request_HEAD ? (SEND_HEADERS + SEND_BODY) : SEND_HEADERS)
        );
}

/*
 * The main http server function.
 * Given a socket, listen for new connections and farm out
 * the processing as a [v]forked process.
 * Never returns.
 */
#if BB_MMU
static void mini_httpd(int server_socket) NORETURN;
static void mini_httpd(int server_socket)
{
        /* NB: it's best to not use xfuncs in this loop before fork().
         * Otherwise server may die on transient errors (temporary
         * out-of-memory condition, etc), which is Bad(tm).
         * Try to do any dangerous calls after fork.
         */
        while (1) {
                int n;
                len_and_sockaddr fromAddr;

                /* Wait for connections... */
                fromAddr.len = LSA_SIZEOF_SA;
                n = accept(server_socket, &fromAddr.u.sa, &fromAddr.len);
                if (n < 0)
                        continue;
//TODO: we can reject connects from denied IPs right away;
//also, we might want to do one MSG_DONTWAIT'ed recv() here
//to detect immediate EOF,
//to avoid forking a whole new process for attackers
//who open and close lots of connections.
//(OTOH, the real mitigtion for this sort of thing is
//to ratelimit connects in iptables)

                /* set the KEEPALIVE option to cull dead connections */
                setsockopt_keepalive(n);

                if (fork() == 0) {
                        /* child */
                        /* Do not reload config on HUP */
                        signal(SIGHUP, SIG_IGN);
                        close(server_socket);
                        xmove_fd(n, 0);
                        xdup2(0, 1);

                        handle_incoming_and_exit(&fromAddr);
                }
                /* parent, or fork failed */
                close(n);
        } /* while (1) */
        /* never reached */
}
#else
static void mini_httpd_nommu(int server_socket, int argc, char **argv) NORETURN;
static void mini_httpd_nommu(int server_socket, int argc, char **argv)
{
        char *argv_copy[argc + 2];

        argv_copy[0] = argv[0];
        argv_copy[1] = (char*)"-i";
        memcpy(&argv_copy[2], &argv[1], argc * sizeof(argv[0]));

        /* NB: it's best to not use xfuncs in this loop before vfork().
         * Otherwise server may die on transient errors (temporary
         * out-of-memory condition, etc), which is Bad(tm).
         * Try to do any dangerous calls after fork.
         */
        while (1) {
                int n;

                /* Wait for connections... */
                n = accept(server_socket, NULL, NULL);
                if (n < 0)
                        continue;

                /* set the KEEPALIVE option to cull dead connections */
                setsockopt_keepalive(n);

                if (vfork() == 0) {
                        /* child */
                        /* Do not reload config on HUP */
                        signal(SIGHUP, SIG_IGN);
                        close(server_socket);
                        xmove_fd(n, 0);
                        xdup2(0, 1);

                        /* Run a copy of ourself in inetd mode */
                        re_exec(argv_copy);
                }
                argv_copy[0][0] &= 0x7f;
                /* parent, or vfork failed */
                close(n);
        } /* while (1) */
        /* never reached */
}
#endif

/*
 * Process a HTTP connection on stdin/out.
 * Never returns.
 */
static void mini_httpd_inetd(void) NORETURN;
static void mini_httpd_inetd(void)
{
        len_and_sockaddr fromAddr;

        memset(&fromAddr, 0, sizeof(fromAddr));
        fromAddr.len = LSA_SIZEOF_SA;
        /* NB: can fail if user runs it by hand and types in http cmds */
        getpeername(0, &fromAddr.u.sa, &fromAddr.len);
        handle_incoming_and_exit(&fromAddr);
}

static void sighup_handler(int sig UNUSED_PARAM)
{
        int sv = errno;
        parse_conf(DEFAULT_PATH_HTTPD_CONF, SIGNALED_PARSE);
        errno = sv;
}

enum {
        c_opt_config_file = 0,
        d_opt_decode_url,
        h_opt_home_httpd,
        IF_FEATURE_HTTPD_ENCODE_URL_STR(e_opt_encode_url,)
        IF_FEATURE_HTTPD_BASIC_AUTH(    r_opt_realm     ,)
        IF_FEATURE_HTTPD_AUTH_MD5(      m_opt_md5       ,)
        IF_FEATURE_HTTPD_SETUID(        u_opt_setuid    ,)
        p_opt_port      ,
        p_opt_inetd     ,
        p_opt_foreground,
        p_opt_verbose   ,
        OPT_CONFIG_FILE = 1 << c_opt_config_file,
        OPT_DECODE_URL  = 1 << d_opt_decode_url,
        OPT_HOME_HTTPD  = 1 << h_opt_home_httpd,
        OPT_ENCODE_URL  = IF_FEATURE_HTTPD_ENCODE_URL_STR((1 << e_opt_encode_url)) + 0,
        OPT_REALM       = IF_FEATURE_HTTPD_BASIC_AUTH(    (1 << r_opt_realm     )) + 0,
        OPT_MD5         = IF_FEATURE_HTTPD_AUTH_MD5(      (1 << m_opt_md5       )) + 0,
        OPT_SETUID      = IF_FEATURE_HTTPD_SETUID(        (1 << u_opt_setuid    )) + 0,
        OPT_PORT        = 1 << p_opt_port,
        OPT_INETD       = 1 << p_opt_inetd,
        OPT_FOREGROUND  = 1 << p_opt_foreground,
        OPT_VERBOSE     = 1 << p_opt_verbose,
};


int httpd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int httpd_main(int argc UNUSED_PARAM, char **argv)
{
        int server_socket = server_socket; /* for gcc */
        unsigned opt;
        char *url_for_decode;
        IF_FEATURE_HTTPD_ENCODE_URL_STR(const char *url_for_encode;)
        IF_FEATURE_HTTPD_SETUID(const char *s_ugid = NULL;)
        IF_FEATURE_HTTPD_SETUID(struct bb_uidgid_t ugid;)
        IF_FEATURE_HTTPD_AUTH_MD5(const char *pass;)

        INIT_G();

#if ENABLE_LOCALE_SUPPORT
        /* Undo busybox.c: we want to speak English in http (dates etc) */
        setlocale(LC_TIME, "C");
#endif

        home_httpd = xrealloc_getcwd_or_warn(NULL);
        /* We do not "absolutize" path given by -h (home) opt.
         * If user gives relative path in -h,
         * $SCRIPT_FILENAME will not be set. */
        opt = getopt32(argv, "^"
                        "c:d:h:"
                        IF_FEATURE_HTTPD_ENCODE_URL_STR("e:")
                        IF_FEATURE_HTTPD_BASIC_AUTH("r:")
                        IF_FEATURE_HTTPD_AUTH_MD5("m:")
                        IF_FEATURE_HTTPD_SETUID("u:")
                        "p:ifv"
                        "\0"
                        /* -v counts, -i implies -f */
                        "vv:if",
                        &opt_c_configFile, &url_for_decode, &home_httpd
                        IF_FEATURE_HTTPD_ENCODE_URL_STR(, &url_for_encode)
                        IF_FEATURE_HTTPD_BASIC_AUTH(, &g_realm)
                        IF_FEATURE_HTTPD_AUTH_MD5(, &pass)
                        IF_FEATURE_HTTPD_SETUID(, &s_ugid)
                        , &bind_addr_or_port
                        , &verbose
                );
        if (opt & OPT_DECODE_URL) {
                fputs_stdout(percent_decode_in_place(url_for_decode, /*strict:*/ 0));
                return 0;
        }
#if ENABLE_FEATURE_HTTPD_ENCODE_URL_STR
        if (opt & OPT_ENCODE_URL) {
                fputs_stdout(encodeString(url_for_encode));
                return 0;
        }
#endif
#if ENABLE_FEATURE_HTTPD_AUTH_MD5
        if (opt & OPT_MD5) {
                char salt[sizeof("$1$XXXXXXXX")];
                salt[0] = '$';
                salt[1] = '1';
                salt[2] = '$';
                crypt_make_salt(salt + 3, 4);
                puts(pw_encrypt(pass, salt, /*cleanup:*/ 0));
                return 0;
        }
#endif
#if ENABLE_FEATURE_HTTPD_SETUID
        if (opt & OPT_SETUID) {
                xget_uidgid(&ugid, s_ugid);
        }
#endif

#if !BB_MMU
        if (!(opt & OPT_FOREGROUND)) {
                bb_daemonize_or_rexec(0, argv); /* don't change current directory */
                re_execed = 0; /* for the following chdir to work */
        }
#endif
        /* Chdir to home (unless we were re_exec()ed for NOMMU case
         * in mini_httpd_nommu(): we are already in the home dir then).
         */
        if (!re_execed)
                xchdir(home_httpd);

        if (!(opt & OPT_INETD)) {
                signal(SIGCHLD, SIG_IGN);
                server_socket = openServer();
#if ENABLE_FEATURE_HTTPD_SETUID
                /* drop privileges */
                if (opt & OPT_SETUID) {
                        if (ugid.gid != (gid_t)-1) {
                                if (setgroups(1, &ugid.gid) == -1)
                                        bb_simple_perror_msg_and_die("setgroups");
                                xsetgid(ugid.gid);
                        }
                        xsetuid(ugid.uid);
                }
#endif
        }

#if 0
        /* User can do it himself: 'env - PATH="$PATH" httpd'
         * We don't do it because we don't want to screw users
         * which want to do
         * 'env - VAR1=val1 VAR2=val2 httpd'
         * and have VAR1 and VAR2 values visible in their CGIs.
         * Besides, it is also smaller. */
        {
                char *p = getenv("PATH");
                /* env strings themself are not freed, no need to xstrdup(p): */
                clearenv();
                if (p)
                        putenv(p - 5);
//              if (!(opt & OPT_INETD))
//                      setenv_long("SERVER_PORT", ???);
        }
#endif

        parse_conf(DEFAULT_PATH_HTTPD_CONF, FIRST_PARSE);
        if (!(opt & OPT_INETD))
                signal(SIGHUP, sighup_handler);

        xfunc_error_retval = 0;
        if (opt & OPT_INETD)
                mini_httpd_inetd(); /* never returns */
#if BB_MMU
        if (!(opt & OPT_FOREGROUND))
                bb_daemonize(0); /* don't change current directory */
        mini_httpd(server_socket); /* never returns */
#else
        mini_httpd_nommu(server_socket, argc, argv); /* never returns */
#endif
        /* return 0; */
}