/* vi: set sw=4 ts=4: */
/*
 * issue.c: issue printing code
 *
 * Copyright (C) 2003 Bastian Blank <waldi@tuxbox.org>
 *
 * Optimize and correcting OCRNL by Vladimir Oleynik <dzo@simtreas.ru>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
#include "libbb.h"
/* After libbb.h, since it needs sys/types.h on some systems */
#include <sys/utsname.h>

#define LOGIN " login: "

static const char fmtstr_d[] ALIGN1 = "%A, %d %B %Y";

void FAST_FUNC print_login_issue(const char *issue_file, const char *tty)
{
        FILE *fp;
        int c;
        char buf[256+1];
        const char *outbuf;
        time_t t;
        struct utsname uts;

        time(&t);
        uname(&uts);

        puts("\r");  /* start a new line */

        fp = fopen_for_read(issue_file);
        if (!fp)
                return;
        while ((c = fgetc(fp)) != EOF) {
                outbuf = buf;
                buf[0] = c;
                buf[1] = '\0';
                if (c == '\n') {
                        buf[1] = '\r';
                        buf[2] = '\0';
                }
                if (c == '\\' || c == '%') {
                        c = fgetc(fp);
                        switch (c) {
//From getty manpage (* - supported by us)
//========================================
//4 or 4{interface}
//  Insert the IPv4 address of the network interface (example: \4{eth0}).
//  If the interface argument is not specified, then select the first
//  fully configured (UP, non-LOOPBACK, RUNNING) interface.
//6 or 6{interface} -- The same as \4 but for IPv6.
//b -- Insert the baudrate of the current line.
//*d -- Insert the current date.
//*t -- Insert the current time.
//e or e{name}
//  Translate the human-readable name to an escape sequence and insert it
//  (for example: \e{red}Alert text.\e{reset}).  If the name argument
//  is not specified, then insert \033. The currently supported names are:
//  black, blink, blue, bold, brown, cyan, darkgray, gray, green, halfbright,
//  lightblue, lightcyan, lightgray, lightgreen, lightmagenta, lightred,
//  magenta, red, reset, reverse, and yellow. Unknown names are ignored.
//*s
//  Insert the system name (the name of the operating system - `uname -s`)
//*S or S{VARIABLE}
//  Insert the VARIABLE data from /etc/os-release.
//  If the VARIABLE argument is not specified, use PRETTY_NAME.
//  If PRETTY_NAME is not in /etc/os-release, \S is the same as \s.
//*l -- Insert the name of the current tty line.
//*m -- Insert the architecture identifier of the machine: `uname -m`.
//*n -- Insert the nodename of the machine: `uname -n`.
//*o -- Insert the NIS domainname of the machine.  Same as `hostname -d'.
//*O -- Insert the DNS domainname of the machine.
//*r -- Insert the release number of the OS: `uname -r`.
//u -- Insert the number of current users logged in.
//U -- Insert the string "1 user" or "N users" (current users logged in).
//*v -- Insert the version of the OS, e.g. the build-date etc: `uname -v`.
//We also implement:
//*D -- same as \O "DNS domainname"
//*h -- same as \n "nodename"

                        case 'S':
                                /* minimal implementation, not reading /etc/os-release */
                                /*FALLTHROUGH*/
                        case 's':
                                outbuf = uts.sysname;
                                break;
                        case 'n':
                        case 'h':
                                outbuf = uts.nodename;
                                break;
                        case 'r':
                                outbuf = uts.release;
                                break;
                        case 'v':
                                outbuf = uts.version;
                                break;
                        case 'm':
                                outbuf = uts.machine;
                                break;
/* The field domainname of struct utsname is Linux specific. */
#if defined(__linux__)
                        case 'D':
                        case 'o':
                        case 'O':
                                outbuf = uts.domainname;
                                break;
#endif
                        case 'd':
                                strftime(buf, sizeof(buf), fmtstr_d, localtime(&t));
                                break;
                        case 't':
                                strftime_HHMMSS(buf, sizeof(buf), &t);
                                break;
                        case 'l':
                                outbuf = tty;
                                break;
                        default:
                                buf[0] = c;
                        }
                }
                fputs_stdout(outbuf);
        }
        fclose(fp);
        fflush_all();
}

void FAST_FUNC print_login_prompt(void)
{
        char *hostname = safe_gethostname();

        fputs_stdout(hostname);
        fputs_stdout(LOGIN);
        fflush_all();
        free(hostname);
}

/* Clear dangerous stuff, set PATH */
static const char forbid[] ALIGN1 =
        "ENV" "\0"
        "BASH_ENV" "\0"
        "HOME" "\0"
        "IFS" "\0"
        "SHELL" "\0"
        "LD_LIBRARY_PATH" "\0"
        "LD_PRELOAD" "\0"
        "LD_TRACE_LOADED_OBJECTS" "\0"
        "LD_BIND_NOW" "\0"
        "LD_AOUT_LIBRARY_PATH" "\0"
        "LD_AOUT_PRELOAD" "\0"
        "LD_NOWARN" "\0"
        "LD_KEEPDIR" "\0";

int FAST_FUNC sanitize_env_if_suid(void)
{
        const char *p;

        if (getuid() == geteuid())
                return 0;

        p = forbid;
        do {
                unsetenv(p);
                p += strlen(p) + 1;
        } while (*p);
        putenv((char*)bb_PATH_root_path);

        return 1; /* we indeed were run by different user! */
}