mailutils/reformime.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * reformime: parse MIME-encoded message
   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 //config:config REFORMIME
  10 //config:       bool "reformime (7.5 kb)"
  11 //config:       default y
  12 //config:       help
  13 //config:       Parse MIME-formatted messages.
  14 //config:
  15 //config:config FEATURE_REFORMIME_COMPAT
  16 //config:       bool "Accept and ignore options other than -x and -X"
  17 //config:       default y
  18 //config:       depends on REFORMIME
  19 //config:       help
  20 //config:       Accept (for compatibility only) and ignore options
  21 //config:       other than -x and -X.
  22
  23 //applet:IF_REFORMIME(APPLET(reformime, BB_DIR_BIN, BB_SUID_DROP))
  24
  25 //kbuild:lib-$(CONFIG_REFORMIME) += reformime.o mail.o
  26
  27 #include "libbb.h"
  28 #include "mail.h"
  29
  30 #if 0
  31 # define dbg_error_msg(...) bb_error_msg(__VA_ARGS__)
  32 #else
  33 # define dbg_error_msg(...) ((void)0)
  34 #endif
  35
  36 static const char *find_token(const char *const string_array[], const char *key, const char *defvalue)
  37 {
  38         const char *r = NULL;
  39         int i;
  40         for (i = 0; string_array[i] != NULL; i++) {
  41                 if (strcasecmp(string_array[i], key) == 0) {
  42                         r = (char *)string_array[i+1];
  43                         break;
  44                 }
  45         }
  46         return (r) ? r : defvalue;
  47 }
  48
  49 static const char *xfind_token(const char *const string_array[], const char *key)
  50 {
  51         const char *r = find_token(string_array, key, NULL);
  52         if (r)
  53                 return r;
  54         bb_error_msg_and_die("not found: '%s'", key);
  55 }
  56
  57 enum {
  58         OPT_x = 1 << 0,
  59         OPT_X = 1 << 1,
  60 #if ENABLE_FEATURE_REFORMIME_COMPAT
  61         OPT_d = 1 << 2,
  62         OPT_e = 1 << 3,
  63         OPT_i = 1 << 4,
  64         OPT_s = 1 << 5,
  65         OPT_r = 1 << 6,
  66         OPT_c = 1 << 7,
  67         OPT_m = 1 << 8,
  68         OPT_h = 1 << 9,
  69         OPT_o = 1 << 10,
  70         OPT_O = 1 << 11,
  71 #endif
  72 };
  73
  74 static int parse(const char *boundary, char **argv)
  75 {
  76         int boundary_len = strlen(boundary);
  77         char uniq[sizeof("%%llu.%u") + sizeof(int)*3];
  78
  79         dbg_error_msg("BOUNDARY[%s]", boundary);
  80
  81         // prepare unique string pattern
  82         sprintf(uniq, "%%llu.%u", (unsigned)getpid());
  83         dbg_error_msg("UNIQ[%s]", uniq);
  84
  85         while (1) {
  86                 char *header;
  87                 const char *tokens[32]; /* 32 is enough */
  88                 const char *type;
  89
  90                 /* Read the header (everything up to two \n) */
  91                 {
  92                         unsigned header_idx = 0;
  93                         int last_ch = 0;
  94                         header = NULL;
  95                         while (1) {
  96                                 int ch = fgetc(stdin);
  97                                 if (ch == '\r') /* Support both line endings */
  98                                         continue;
  99                                 if (ch == EOF)
 100                                         break;
 101                                 if (ch == '\n' && last_ch == ch)
 102                                         break;
 103                                 if (!(header_idx & 0xff))
 104                                         header = xrealloc(header, header_idx + 0x101);
 105                                 header[header_idx++] = last_ch = ch;
 106                         }
 107                         if (!header) {
 108                                 dbg_error_msg("EOF");
 109                                 break;
 110                         }
 111                         header[header_idx] = '\0';
 112                         dbg_error_msg("H:'%s'", p);
 113                 }
 114
 115                 /* Split to tokens */
 116                 {
 117                         char *s, *p;
 118                         unsigned ntokens;
 119                         const char *delims = ";=\" \t\n";
 120
 121                         /* Skip to last Content-Type: */
 122                         s = p = header;
 123                         while ((p = strchr(p, '\n')) != NULL) {
 124                                 p++;
 125                                 if (strncasecmp(p, "Content-Type:", sizeof("Content-Type:")-1) == 0)
 126                                         s = p;
 127                         }
 128                         dbg_error_msg("L:'%s'", p);
 129                         ntokens = 0;
 130                         s = strtok(s, delims);
 131                         while (s) {
 132                                 tokens[ntokens] = s;
 133                                 if (ntokens < ARRAY_SIZE(tokens) - 1)
 134                                         ntokens++;
 135                                 dbg_error_msg("L[%d]='%s'", ntokens, s);
 136                                 s = strtok(NULL, delims);
 137                         }
 138                         tokens[ntokens] = NULL;
 139                         dbg_error_msg("EMPTYLINE, ntokens:%d", ntokens);
 140                         if (ntokens == 0)
 141                                 break;
 142                 }
 143
 144                 /* Is it multipart? */
 145                 type = find_token(tokens, "Content-Type:", "text/plain");
 146                 dbg_error_msg("TYPE:'%s'", type);
 147                 if (0 == strncasecmp(type, "multipart/", 10)) {
 148                         /* Yes, recurse */
 149                         if (strcasecmp(type + 10, "mixed") != 0)
 150                                 bb_error_msg_and_die("no support of content type '%s'", type);
 151                         parse(xfind_token(tokens, "boundary"), argv);
 152                 } else {
 153                         /* No, process one non-multipart section */
 154                         char *end;
 155                         pid_t pid = pid;
 156                         FILE *fp;
 157
 158                         const char *charset = find_token(tokens, "charset", CONFIG_FEATURE_MIME_CHARSET);
 159                         const char *encoding = find_token(tokens, "Content-Transfer-Encoding:", "7bit");
 160
 161                         /* Compose target filename */
 162                         char *filename = (char *)find_token(tokens, "filename", NULL);
 163                         if (!filename)
 164                                 filename = xasprintf(uniq, monotonic_us());
 165                         else
 166                                 filename = bb_get_last_path_component_strip(xstrdup(filename));
 167
 168                         if (opts & OPT_X) {
 169                                 int fd[2];
 170
 171                                 /* start external helper */
 172                                 xpipe(fd);
 173                                 pid = vfork();
 174                                 if (0 == pid) {
 175                                         /* child reads from fd[0] */
 176                                         close(fd[1]);
 177                                         xmove_fd(fd[0], STDIN_FILENO);
 178                                         xsetenv("CONTENT_TYPE", type);
 179                                         xsetenv("CHARSET", charset);
 180                                         xsetenv("ENCODING", encoding);
 181                                         xsetenv("FILENAME", filename);
 182                                         BB_EXECVP_or_die(argv);
 183                                 }
 184                                 /* parent will write to fd[1] */
 185                                 close(fd[0]);
 186                                 fp = xfdopen_for_write(fd[1]);
 187                                 signal(SIGPIPE, SIG_IGN);
 188                         } else {
 189                                 /* write to file */
 190                                 char *fname = xasprintf("%s%s", *argv, filename);
 191                                 fp = xfopen_for_write(fname);
 192                                 free(fname);
 193                         }
 194                         free(filename);
 195
 196                         /* write to fp */
 197                         end = NULL;
 198                         if (0 == strcasecmp(encoding, "base64")) {
 199                                 read_base64(stdin, fp, '-');
 200                         } else
 201                         if (0 != strcasecmp(encoding, "7bit")
 202                          && 0 != strcasecmp(encoding, "8bit")
 203                         ) {
 204                                 /* quoted-printable, binary, user-defined are unsupported so far */
 205                                 bb_error_msg_and_die("encoding '%s' not supported", encoding);
 206                         } else {
 207                                 /* plain 7bit or 8bit */
 208                                 while ((end = xmalloc_fgets(stdin)) != NULL) {
 209                                         if ('-' == end[0]
 210                                          && '-' == end[1]
 211                                          && strncmp(end + 2, boundary, boundary_len) == 0
 212                                         ) {
 213                                                 break;
 214                                         }
 215                                         fputs(end, fp);
 216                                 }
 217                         }
 218                         fclose(fp);
 219
 220                         /* Wait for child */
 221                         if (opts & OPT_X) {
 222                                 int rc;
 223                                 signal(SIGPIPE, SIG_DFL);
 224                                 rc = (wait4pid(pid) & 0xff);
 225                                 if (rc != 0)
 226                                         return rc + 20;
 227                         }
 228
 229                         /* Multipart ended? */
 230                         if (end && '-' == end[2 + boundary_len] && '-' == end[2 + boundary_len + 1]) {
 231                                 dbg_error_msg("FINISHED MPART:'%s'", end);
 232                                 break;
 233                         }
 234                         dbg_error_msg("FINISHED:'%s'", end);
 235                         free(end);
 236                 } /* end of "handle one non-multipart block" */
 237
 238                 free(header);
 239         } /* while (1) */
 240
 241         dbg_error_msg("ENDPARSE[%s]", boundary);
 242
 243         return EXIT_SUCCESS;
 244 }
 245
 246 //usage:#define reformime_trivial_usage
 247 //usage:       "[OPTIONS]"
 248 //usage:#define reformime_full_usage "\n\n"
 249 //usage:       "Parse MIME-encoded message on stdin\n"
 250 //usage:     "\n        -x PREFIX       Extract content of MIME sections to files"
 251 //usage:     "\n        -X PROG ARGS    Filter content of MIME sections through PROG"
 252 //usage:     "\n                        Must be the last option"
 253 //usage:     "\n"
 254 //usage:     "\nOther options are silently ignored"
 255
 256 /*
 257 Usage: reformime [options]
 258     -d - parse a delivery status notification.
 259     -e - extract contents of MIME section.
 260     -x - extract MIME section to a file.
 261     -X - pipe MIME section to a program.
 262     -i - show MIME info.
 263     -s n.n.n.n - specify MIME section.
 264     -r - rewrite message, filling in missing MIME headers.
 265     -r7 - also convert 8bit/raw encoding to quoted-printable, if possible.
 266     -r8 - also convert quoted-printable encoding to 8bit, if possible.
 267     -c charset - default charset for rewriting, -o, and -O.
 268     -m [file] [file]... - create a MIME message digest.
 269     -h "header" - decode RFC 2047-encoded header.
 270     -o "header" - encode unstructured header using RFC 2047.
 271     -O "header" - encode address list header using RFC 2047.
 272 */
 273
 274 int reformime_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 275 int reformime_main(int argc UNUSED_PARAM, char **argv)
 276 {
 277         const char *opt_prefix = "";
 278
 279         INIT_G();
 280
 281         // parse options
 282         // N.B. only -x and -X are supported so far
 283         opts = getopt32(argv, "^"
 284                 "x:X" IF_FEATURE_REFORMIME_COMPAT("deis:r:c:m:*h:o:O:")
 285                 "\0" "x--X:X--x",
 286                 &opt_prefix
 287                 IF_FEATURE_REFORMIME_COMPAT(, NULL, NULL, &G.opt_charset, NULL, NULL, NULL, NULL)
 288         );
 289         argv += optind;
 290
 291         return parse("", (opts & OPT_X) ? argv : (char **)&opt_prefix);
 292 }