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