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 tarball for details.
   8  */
   9 #include "libbb.h"
  10 #include "mail.h"
  11
  12 static 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
  21 static 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
  42 void 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
  78 const 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 /*
  93 static 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
 113 void 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
 120 #define src_buf text
 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 = bb_common_bufsiz1;
 128         // N.B. strlen(NULL) segfaults!
 129         } else if (text) {
 130                 // though we do not call uuencode(NULL, NULL) explicitly
 131                 // still we do not want to break things suddenly
 132                 len = strlen(text);
 133         } else
 134                 return;
 135
 136         while (1) {
 137                 size_t size;
 138                 if (fname) {
 139                         size = fread((char *)src_buf, 1, SRC_BUF_SIZE, fp);
 140                         if ((ssize_t)size < 0)
 141                                 bb_perror_msg_and_die(bb_msg_read_error);
 142                 } else {
 143                         size = len;
 144                         if (len > SRC_BUF_SIZE)
 145                                 size = SRC_BUF_SIZE;
 146                 }
 147                 if (!size)
 148                         break;
 149                 // encode the buffer we just read in
 150                 bb_uuencode(dst_buf, src_buf, size, bb_uuenc_tbl_base64);
 151                 if (fname) {
 152                         printf("%s\n", eol);
 153                 } else {
 154                         src_buf += size;
 155                         len -= size;
 156                 }
 157                 fwrite(dst_buf, 1, 4 * ((size + 2) / 3), stdout);
 158         }
 159         if (fname && NOT_LONE_DASH(fname))
 160                 fclose(fp);
 161 #undef src_buf
 162 }
 163
 164 void FAST_FUNC decode_base64(FILE *src_stream, FILE *dst_stream)
 165 {
 166         int term_count = 1;
 167
 168         while (1) {
 169                 char translated[4];
 170                 int count = 0;
 171
 172                 while (count < 4) {
 173                         char *table_ptr;
 174                         int ch;
 175
 176                         /* Get next _valid_ character.
 177                          * global vector bb_uuenc_tbl_base64[] contains this string:
 178                          * "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=\n"
 179                          */
 180                         do {
 181                                 ch = fgetc(src_stream);
 182                                 if (ch == EOF) {
 183                                         bb_error_msg_and_die(bb_msg_read_error);
 184                                 }
 185                                 // - means end of MIME section
 186                                 if ('-' == ch) {
 187                                         // push it back
 188                                         ungetc(ch, src_stream);
 189                                         return;
 190                                 }
 191                                 table_ptr = strchr(bb_uuenc_tbl_base64, ch);
 192                         } while (table_ptr == NULL);
 193
 194                         /* Convert encoded character to decimal */
 195                         ch = table_ptr - bb_uuenc_tbl_base64;
 196
 197                         if (*table_ptr == '=') {
 198                                 if (term_count == 0) {
 199                                         translated[count] = '\0';
 200                                         break;
 201                                 }
 202                                 term_count++;
 203                         } else if (*table_ptr == '\n') {
 204                                 /* Check for terminating line */
 205                                 if (term_count == 5) {
 206                                         return;
 207                                 }
 208                                 term_count = 1;
 209                                 continue;
 210                         } else {
 211                                 translated[count] = ch;
 212                                 count++;
 213                                 term_count = 0;
 214                         }
 215                 }
 216
 217                 /* Merge 6 bit chars to 8 bit */
 218                 if (count > 1) {
 219                         fputc(translated[0] << 2 | translated[1] >> 4, dst_stream);
 220                 }
 221                 if (count > 2) {
 222                         fputc(translated[1] << 4 | translated[2] >> 2, dst_stream);
 223                 }
 224                 if (count > 3) {
 225                         fputc(translated[2] << 6 | translated[3], dst_stream);
 226                 }
 227         }
 228 }
 229
 230
 231 /*
 232  * get username and password from a file descriptor
 233  */
 234 void FAST_FUNC get_cred_or_die(int fd)
 235 {
 236         if (isatty(fd)) {
 237                 G.user = xstrdup(bb_ask(fd, /* timeout: */ 0, "User: "));
 238                 G.pass = xstrdup(bb_ask(fd, /* timeout: */ 0, "Password: "));
 239         } else {
 240                 G.user = xmalloc_reads(fd, /* pfx: */ NULL, /* maxsize: */ NULL);
 241                 G.pass = xmalloc_reads(fd, /* pfx: */ NULL, /* maxsize: */ NULL);
 242         }
 243         if (!G.user || !*G.user || !G.pass)
 244                 bb_error_msg_and_die("no username or password");
 245 }