LXR busybox/mailutils/mail.c

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * helper routines
   4 *
   5 * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
   6 *
   7 * Licensed under GPLv2, see file LICENSE in this source tree.
   8 */
   9#include "libbb.h"
  10#include "mail.h"
  11
  12static void kill_helper(void)
  13{
  14        if (G.helper_pid > 0) {
  15                kill(G.helper_pid, SIGTERM);
  16                G.helper_pid = 0;
  17        }
  18}
  19
  20// generic signal handler
  21static void signal_handler(int signo)
  22{
  23#define err signo
  24        if (SIGALRM == signo) {
  25                kill_helper();
  26                bb_error_msg_and_die("timed out");
  27        }
  28
  29        // SIGCHLD. reap zombies
  30        if (safe_waitpid(G.helper_pid, &err, WNOHANG) > 0) {
  31                if (WIFSIGNALED(err))
  32                        bb_error_msg_and_die("helper killed by signal %u", WTERMSIG(err));
  33                if (WIFEXITED(err)) {
  34                        G.helper_pid = 0;
  35                        if (WEXITSTATUS(err))
  36                                bb_error_msg_and_die("helper exited (%u)", WEXITSTATUS(err));
  37                }
  38        }
  39#undef err
  40}
  41
  42void FAST_FUNC launch_helper(const char **argv)
  43{
  44        // setup vanilla unidirectional pipes interchange
  45        int i;
  46        int pipes[4];
  47
  48        xpipe(pipes);
  49        xpipe(pipes + 2);
  50
  51        // NB: handler must be installed before vfork
  52        bb_signals(0
  53                + (1 << SIGCHLD)
  54                + (1 << SIGALRM)
  55                , signal_handler);
  56
  57        G.helper_pid = xvfork();
  58
  59        i = (!G.helper_pid) * 2; // for parent:0, for child:2
  60        close(pipes[i + 1]); // 1 or 3 - closing one write end
  61        close(pipes[2 - i]); // 2 or 0 - closing one read end
  62        xmove_fd(pipes[i], STDIN_FILENO); // 0 or 2 - using other read end
  63        xmove_fd(pipes[3 - i], STDOUT_FILENO); // 3 or 1 - other write end
  64
  65        if (!G.helper_pid) {
  66                // child: try to execute connection helper
  67                // NB: SIGCHLD & SIGALRM revert to SIG_DFL on exec
  68                BB_EXECVP_or_die((char**)argv);
  69        }
  70
  71        // parent
  72        // check whether child is alive
  73        //redundant:signal_handler(SIGCHLD);
  74        // child seems OK -> parent goes on
  75        atexit(kill_helper);
  76}
  77
  78const FAST_FUNC char *command(const char *fmt, const char *param)
  79{
  80        const char *msg = fmt;
  81        if (timeout)
  82                alarm(timeout);
  83        if (msg) {
  84                msg = xasprintf(fmt, param);
  85                printf("%s\r\n", msg);
  86        }
  87        fflush_all();
  88        return msg;
  89}
  90
  91// NB: parse_url can modify url[] (despite const), but only if '@' is there
  92/*
  93static char FAST_FUNC *parse_url(char *url, char **user, char **pass)
  94{
  95        // parse [user[:pass]@]host
  96        // return host
  97        char *s = strchr(url, '@');
  98        *user = *pass = NULL;
  99        if (s) {
 100                *s++ = '\0';
 101                *user = url;
 102                url = s;
 103                s = strchr(*user, ':');
 104                if (s) {
 105                        *s++ = '\0';
 106                        *pass = s;
 107                }
 108        }
 109        return url;
 110}
 111*/
 112
 113void FAST_FUNC encode_base64(char *fname, const char *text, const char *eol)
 114{
 115        enum {
 116                SRC_BUF_SIZE = 45,  /* This *MUST* be a multiple of 3 */
 117                DST_BUF_SIZE = 4 * ((SRC_BUF_SIZE + 2) / 3),
 118        };
 119#define src_buf text
 120        char src[SRC_BUF_SIZE];
 121        FILE *fp = fp;
 122        ssize_t len = len;
 123        char dst_buf[DST_BUF_SIZE + 1];
 124
 125        if (fname) {
 126                fp = (NOT_LONE_DASH(fname)) ? xfopen_for_read(fname) : (FILE *)text;
 127                src_buf = src;
 128        } else if (text) {
 129                // though we do not call uuencode(NULL, NULL) explicitly
 130                // still we do not want to break things suddenly
 131                len = strlen(text);
 132        } else
 133                return;
 134
 135        while (1) {
 136                size_t size;
 137                if (fname) {
 138                        size = fread((char *)src_buf, 1, SRC_BUF_SIZE, fp);
 139                        if ((ssize_t)size < 0)
 140                                bb_perror_msg_and_die(bb_msg_read_error);
 141                } else {
 142                        size = len;
 143                        if (len > SRC_BUF_SIZE)
 144                                size = SRC_BUF_SIZE;
 145                }
 146                if (!size)
 147                        break;
 148                // encode the buffer we just read in
 149                bb_uuencode(dst_buf, src_buf, size, bb_uuenc_tbl_base64);
 150                if (fname) {
 151                        printf("%s\n", eol);
 152                } else {
 153                        src_buf += size;
 154                        len -= size;
 155                }
 156                fwrite(dst_buf, 1, 4 * ((size + 2) / 3), stdout);
 157        }
 158        if (fname && NOT_LONE_DASH(fname))
 159                fclose(fp);
 160#undef src_buf
 161}
 162
 163/*
 164 * get username and password from a file descriptor
 165 */
 166void FAST_FUNC get_cred_or_die(int fd)
 167{
 168        if (isatty(fd)) {
 169                G.user = xstrdup(bb_ask(fd, /* timeout: */ 0, "User: "));
 170                G.pass = xstrdup(bb_ask(fd, /* timeout: */ 0, "Password: "));
 171        } else {
 172                G.user = xmalloc_reads(fd, /* pfx: */ NULL, /* maxsize: */ NULL);
 173                G.pass = xmalloc_reads(fd, /* pfx: */ NULL, /* maxsize: */ NULL);
 174        }
 175        if (!G.user || !*G.user || !G.pass)
 176                bb_error_msg_and_die("no username or password");
 177}
 178