LXR busybox/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
  36static 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
  49static 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
  57enum {
  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
  74static 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/*
 257Usage: 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
 274int reformime_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 275int 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}
 293