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 = vfork();
  58         if (G.helper_pid < 0)
  59                 bb_perror_msg_and_die("vfork");
  60
  61         i = (!G.helper_pid) * 2; // for parent:0, for child:2
  62         close(pipes[i + 1]); // 1 or 3 - closing one write end
  63         close(pipes[2 - i]); // 2 or 0 - closing one read end
  64         xmove_fd(pipes[i], STDIN_FILENO); // 0 or 2 - using other read end
  65         xmove_fd(pipes[3 - i], STDOUT_FILENO); // 3 or 1 - other write end
  66
  67         if (!G.helper_pid) {
  68                 // child: try to execute connection helper
  69                 // NB: SIGCHLD & SIGALRM revert to SIG_DFL on exec
  70                 BB_EXECVP(argv[0], (char **)argv);
  71                 bb_perror_msg_and_die("can't execute '%s'", argv[0]);
  72         }
  73
  74         // parent
  75         // check whether child is alive
  76         //redundant:signal_handler(SIGCHLD);
  77         // child seems OK -> parent goes on
  78         atexit(kill_helper);
  79 }
  80
  81 const FAST_FUNC char *command(const char *fmt, const char *param)
  82 {
  83         const char *msg = fmt;
  84         if (timeout)
  85                 alarm(timeout);
  86         if (msg) {
  87                 msg = xasprintf(fmt, param);
  88                 printf("%s\r\n", msg);
  89         }
  90         fflush_all();
  91         return msg;
  92 }
  93
  94 // NB: parse_url can modify url[] (despite const), but only if '@' is there
  95 /*
  96 static char FAST_FUNC *parse_url(char *url, char **user, char **pass)
  97 {
  98         // parse [user[:pass]@]host
  99         // return host
 100         char *s = strchr(url, '@');
 101         *user = *pass = NULL;
 102         if (s) {
 103                 *s++ = '\0';
 104                 *user = url;
 105                 url = s;
 106                 s = strchr(*user, ':');
 107                 if (s) {
 108                         *s++ = '\0';
 109                         *pass = s;
 110                 }
 111         }
 112         return url;
 113 }
 114 */
 115
 116 void FAST_FUNC encode_base64(char *fname, const char *text, const char *eol)
 117 {
 118         enum {
 119                 SRC_BUF_SIZE = 45,  /* This *MUST* be a multiple of 3 */
 120                 DST_BUF_SIZE = 4 * ((SRC_BUF_SIZE + 2) / 3),
 121         };
 122
 123 #define src_buf text
 124         FILE *fp = fp;
 125         ssize_t len = len;
 126         char dst_buf[DST_BUF_SIZE + 1];
 127
 128         if (fname) {
 129                 fp = (NOT_LONE_DASH(fname)) ? xfopen_for_read(fname) : (FILE *)text;
 130                 src_buf = bb_common_bufsiz1;
 131         // N.B. strlen(NULL) segfaults!
 132         } else if (text) {
 133                 // though we do not call uuencode(NULL, NULL) explicitly
 134                 // still we do not want to break things suddenly
 135                 len = strlen(text);
 136         } else
 137                 return;
 138
 139         while (1) {
 140                 size_t size;
 141                 if (fname) {
 142                         size = fread((char *)src_buf, 1, SRC_BUF_SIZE, fp);
 143                         if ((ssize_t)size < 0)
 144                                 bb_perror_msg_and_die(bb_msg_read_error);
 145                 } else {
 146                         size = len;
 147                         if (len > SRC_BUF_SIZE)
 148                                 size = SRC_BUF_SIZE;
 149                 }
 150                 if (!size)
 151                         break;
 152                 // encode the buffer we just read in
 153                 bb_uuencode(dst_buf, src_buf, size, bb_uuenc_tbl_base64);
 154                 if (fname) {
 155                         printf("%s\n", eol);
 156                 } else {
 157                         src_buf += size;
 158                         len -= size;
 159                 }
 160                 fwrite(dst_buf, 1, 4 * ((size + 2) / 3), stdout);
 161         }
 162         if (fname && NOT_LONE_DASH(fname))
 163                 fclose(fp);
 164 #undef src_buf
 165 }
 166
 167 void FAST_FUNC decode_base64(FILE *src_stream, FILE *dst_stream)
 168 {
 169         int term_count = 1;
 170
 171         while (1) {
 172                 char translated[4];
 173                 int count = 0;
 174
 175                 while (count < 4) {
 176                         char *table_ptr;
 177                         int ch;
 178
 179                         /* Get next _valid_ character.
 180                          * global vector bb_uuenc_tbl_base64[] contains this string:
 181                          * "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=\n"
 182                          */
 183                         do {
 184                                 ch = fgetc(src_stream);
 185                                 if (ch == EOF) {
 186                                         bb_error_msg_and_die(bb_msg_read_error);
 187                                 }
 188                                 // - means end of MIME section
 189                                 if ('-' == ch) {
 190                                         // push it back
 191                                         ungetc(ch, src_stream);
 192                                         return;
 193                                 }
 194                                 table_ptr = strchr(bb_uuenc_tbl_base64, ch);
 195                         } while (table_ptr == NULL);
 196
 197                         /* Convert encoded character to decimal */
 198                         ch = table_ptr - bb_uuenc_tbl_base64;
 199
 200                         if (*table_ptr == '=') {
 201                                 if (term_count == 0) {
 202                                         translated[count] = '\0';
 203                                         break;
 204                                 }
 205                                 term_count++;
 206                         } else if (*table_ptr == '\n') {
 207                                 /* Check for terminating line */
 208                                 if (term_count == 5) {
 209                                         return;
 210                                 }
 211                                 term_count = 1;
 212                                 continue;
 213                         } else {
 214                                 translated[count] = ch;
 215                                 count++;
 216                                 term_count = 0;
 217                         }
 218                 }
 219
 220                 /* Merge 6 bit chars to 8 bit */
 221                 if (count > 1) {
 222                         fputc(translated[0] << 2 | translated[1] >> 4, dst_stream);
 223                 }
 224                 if (count > 2) {
 225                         fputc(translated[1] << 4 | translated[2] >> 2, dst_stream);
 226                 }
 227                 if (count > 3) {
 228                         fputc(translated[2] << 6 | translated[3], dst_stream);
 229                 }
 230         }
 231 }
 232
 233
 234 /*
 235  * get username and password from a file descriptor
 236  */
 237 void FAST_FUNC get_cred_or_die(int fd)
 238 {
 239         if (isatty(fd)) {
 240                 G.user = xstrdup(bb_ask(fd, /* timeout: */ 0, "User: "));
 241                 G.pass = xstrdup(bb_ask(fd, /* timeout: */ 0, "Password: "));
 242         } else {
 243                 G.user = xmalloc_reads(fd, /* pfx: */ NULL, /* maxsize: */ NULL);
 244                 G.pass = xmalloc_reads(fd, /* pfx: */ NULL, /* maxsize: */ NULL);
 245         }
 246         if (!G.user || !*G.user || !G.pass)
 247                 bb_error_msg_and_die("no username or password");
 248 }