mailutils/popmaildir.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * popmaildir: a simple yet powerful POP3 client
   4  * Delivers contents of remote mailboxes to local Maildir
   5  *
   6  * Inspired by original utility by Nikola Vladov
   7  *
   8  * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
   9  *
  10  * Licensed under GPLv2, see file LICENSE in this source tree.
  11  */
  12 //config:config POPMAILDIR
  13 //config:       bool "popmaildir (11 kb)"
  14 //config:       default y
  15 //config:       help
  16 //config:       Simple yet powerful POP3 mail popper. Delivers content
  17 //config:       of remote mailboxes to local Maildir.
  18 //config:
  19 //config:config FEATURE_POPMAILDIR_DELIVERY
  20 //config:       bool "Allow message filters and custom delivery program"
  21 //config:       default y
  22 //config:       depends on POPMAILDIR
  23 //config:       help
  24 //config:       Allow to use a custom program to filter the content
  25 //config:       of the message before actual delivery (-F "prog [args...]").
  26 //config:       Allow to use a custom program for message actual delivery
  27 //config:       (-M "prog [args...]").
  28
  29 //applet:IF_POPMAILDIR(APPLET(popmaildir, BB_DIR_USR_SBIN, BB_SUID_DROP))
  30
  31 //kbuild:lib-$(CONFIG_POPMAILDIR) += popmaildir.o mail.o
  32
  33 //usage:#define popmaildir_trivial_usage
  34 //usage:       "[OPTIONS] MAILDIR [CONN_HELPER ARGS]"
  35 //usage:#define popmaildir_full_usage "\n\n"
  36 //usage:       "Fetch content of remote mailbox to local maildir\n"
  37 /* //usage:  "\n        -b              Binary mode. Ignored" */
  38 /* //usage:  "\n        -d              Debug. Ignored" */
  39 /* //usage:  "\n        -m              Show used memory. Ignored" */
  40 /* //usage:  "\n        -V              Show version. Ignored" */
  41 /* //usage:  "\n        -c              Use tcpclient. Ignored" */
  42 /* //usage:  "\n        -a              Use APOP protocol. Implied. If server supports APOP -> use it" */
  43 //usage:     "\n        -s              Skip authorization"
  44 //usage:     "\n        -T              Get messages with TOP instead of RETR"
  45 //usage:     "\n        -k              Keep retrieved messages on the server"
  46 //usage:     "\n        -t SEC          Network timeout"
  47 //usage:        IF_FEATURE_POPMAILDIR_DELIVERY(
  48 //usage:     "\n        -F 'PROG ARGS'  Filter program (may be repeated)"
  49 //usage:     "\n        -M 'PROG ARGS'  Delivery program"
  50 //usage:        )
  51 //usage:     "\n"
  52 //usage:     "\nFetch from plain POP3 server:"
  53 //usage:     "\npopmaildir -k DIR nc pop3.server.com 110 <user_and_pass.txt"
  54 //usage:     "\nFetch from SSLed POP3 server and delete fetched emails:"
  55 //usage:     "\npopmaildir DIR -- openssl s_client -quiet -connect pop3.server.com:995 <user_and_pass.txt"
  56 /* //usage:  "\n        -R BYTES        Remove old messages on the server >= BYTES. Ignored" */
  57 /* //usage:  "\n        -Z N1-N2        Remove messages from N1 to N2 (dangerous). Ignored" */
  58 /* //usage:  "\n        -L BYTES        Don't retrieve new messages >= BYTES. Ignored" */
  59 /* //usage:  "\n        -H LINES        Type first LINES of a message. Ignored" */
  60 //usage:
  61 //usage:#define popmaildir_example_usage
  62 //usage:       "$ popmaildir -k ~/Maildir -- nc pop.drvv.ru 110 [<password_file]\n"
  63 //usage:       "$ popmaildir ~/Maildir -- openssl s_client -quiet -connect pop.gmail.com:995 [<password_file]\n"
  64
  65 #include "libbb.h"
  66 #include "mail.h"
  67
  68 static void pop3_checkr(const char *fmt, const char *param, char **ret)
  69 {
  70         char *msg = send_mail_command(fmt, param);
  71 //FIXME: limit max len!!!
  72         char *answer = xmalloc_fgetline(stdin);
  73         if (answer && '+' == answer[0]) {
  74                 free(msg);
  75                 if (G.timeout)
  76                         alarm(0);
  77                 if (ret) {
  78                         // skip "+OK "
  79                         memmove(answer, answer + 4, strlen(answer) - 4);
  80                         *ret = answer;
  81                 } else
  82                         free(answer);
  83                 return;
  84         }
  85         bb_error_msg_and_die("%s failed, reply was: %s", msg, answer);
  86 }
  87
  88 static void pop3_check(const char *fmt, const char *param)
  89 {
  90         pop3_checkr(fmt, param, NULL);
  91 }
  92
  93 int popmaildir_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  94 int popmaildir_main(int argc UNUSED_PARAM, char **argv)
  95 {
  96         unsigned opts;
  97         char *buf;
  98         unsigned nmsg;
  99         char *hostname;
 100         pid_t pid;
 101         const char *retr;
 102 #if ENABLE_FEATURE_POPMAILDIR_DELIVERY
 103         const char *delivery;
 104 #endif
 105         unsigned opt_nlines = 0;
 106
 107         enum {
 108                 OPT_b = 1 << 0,         // -b binary mode. Ignored
 109                 OPT_d = 1 << 1,         // -d,-dd,-ddd debug. Ignored
 110                 OPT_m = 1 << 2,         // -m show used memory. Ignored
 111                 OPT_V = 1 << 3,         // -V version. Ignored
 112                 OPT_c = 1 << 4,         // -c use tcpclient. Ignored
 113                 OPT_a = 1 << 5,         // -a use APOP protocol
 114                 OPT_s = 1 << 6,         // -s skip authorization
 115                 OPT_T = 1 << 7,         // -T get messages with TOP instead with RETR
 116                 OPT_k = 1 << 8,         // -k keep retrieved messages on the server
 117                 OPT_t = 1 << 9,         // -t90 set timeout to 90 sec
 118                 OPT_R = 1 << 10,        // -R20000 remove old messages on the server >= 20000 bytes (requires -k). Ignored
 119                 OPT_Z = 1 << 11,        // -Z11-23 remove messages from 11 to 23 (dangerous). Ignored
 120                 OPT_L = 1 << 12,        // -L50000 not retrieve new messages >= 50000 bytes. Ignored
 121                 OPT_H = 1 << 13,        // -H30 type first 30 lines of a message; (-L12000 -H30). Ignored
 122                 OPT_M = 1 << 14,        // -M\"program arg1 arg2 ...\"; deliver by program. Treated like -F
 123                 OPT_F = 1 << 15,        // -F\"program arg1 arg2 ...\"; filter by program. Treated like -M
 124         };
 125
 126         // init global variables
 127         INIT_G();
 128
 129         // parse options
 130         opts = getopt32(argv, "^"
 131                 "bdmVcasTkt:+" "R:+Z:L:+H:+" IF_FEATURE_POPMAILDIR_DELIVERY("M:F:")
 132                 "\0" "-1:dd",
 133                 &G.timeout, NULL, NULL, NULL, &opt_nlines
 134                 IF_FEATURE_POPMAILDIR_DELIVERY(, &delivery, &delivery) // we treat -M and -F the same
 135         );
 136         //argc -= optind;
 137         argv += optind;
 138
 139         // get auth info
 140         if (!(opts & OPT_s))
 141                 get_cred_or_die(STDIN_FILENO);
 142
 143         // goto maildir
 144         xchdir(*argv++);
 145
 146         // launch connect helper, if any
 147         if (*argv)
 148                 launch_helper((const char **)argv);
 149
 150         // get server greeting
 151         pop3_checkr(NULL, NULL, &buf);
 152
 153         // authenticate (if no -s given)
 154         if (!(opts & OPT_s)) {
 155                 // server supports APOP and we want it?
 156                 if ('<' == buf[0] && (opts & OPT_a)) {
 157                         union { // save a bit of stack
 158                                 md5_ctx_t ctx;
 159                                 char hex[16 * 2 + 1];
 160                         } md5;
 161                         uint32_t res[MD5_OUTSIZE / 4];
 162
 163                         char *s = strchr(buf, '>');
 164                         if (s)
 165                                 s[1] = '\0';
 166                         // get md5 sum of "<stamp>password" string
 167                         md5_begin(&md5.ctx);
 168                         md5_hash(&md5.ctx, buf, strlen(buf));
 169                         md5_hash(&md5.ctx, G.pass, strlen(G.pass));
 170                         md5_end(&md5.ctx, res);
 171                         *bin2hex(md5.hex, (char*)res, 16) = '\0';
 172                         // APOP
 173                         s = xasprintf("%s %s", G.user, md5.hex);
 174                         pop3_check("APOP %s", s);
 175                         free(s);
 176                         free(buf);
 177                 // server ignores APOP -> use simple text authentication
 178                 } else {
 179                         // USER
 180                         pop3_check("USER %s", G.user);
 181                         // PASS
 182                         pop3_check("PASS %s", G.pass);
 183                 }
 184         }
 185
 186         // get mailbox statistics
 187         pop3_checkr("STAT", NULL, &buf);
 188
 189         // prepare message filename suffix
 190         hostname = safe_gethostname();
 191         pid = getpid();
 192
 193         // get messages counter
 194         // NOTE: we don't use xatou(buf) since buf is "nmsg nbytes"
 195         // we only need nmsg and atoi is just exactly what we need
 196         // if atoi fails to convert buf into number it returns 0
 197         // in this case the following loop simply will not be executed
 198         nmsg = atoi(buf);
 199         free(buf);
 200
 201         // loop through messages
 202         retr = (opts & OPT_T) ? xasprintf("TOP %%u %u", opt_nlines) : "RETR %u";
 203         for (; nmsg; nmsg--) {
 204
 205                 char *filename;
 206                 char *target;
 207                 char *answer;
 208                 FILE *fp;
 209 #if ENABLE_FEATURE_POPMAILDIR_DELIVERY
 210                 int rc;
 211 #endif
 212                 // generate unique filename
 213                 filename  = xasprintf("tmp/%llu.%u.%s",
 214                         monotonic_us(), (unsigned)pid, hostname);
 215
 216                 // retrieve message in ./tmp/ unless filter is specified
 217                 pop3_check(retr, (const char *)(ptrdiff_t)nmsg);
 218
 219 #if ENABLE_FEATURE_POPMAILDIR_DELIVERY
 220                 // delivery helper ordered? -> setup pipe
 221                 if (opts & (OPT_F|OPT_M)) {
 222                         // helper will have $FILENAME set to filename
 223                         xsetenv("FILENAME", filename);
 224                         fp = popen(delivery, "w");
 225                         unsetenv("FILENAME");
 226                         if (!fp) {
 227                                 bb_simple_perror_msg("delivery helper");
 228                                 break;
 229                         }
 230                 } else
 231 #endif
 232                 // create and open file filename
 233                 fp = xfopen_for_write(filename);
 234
 235                 // copy stdin to fp (either filename or delivery helper)
 236                 while ((answer = xmalloc_fgets_str(stdin, "\r\n")) != NULL) {
 237                         char *s = answer;
 238                         if ('.' == answer[0]) {
 239                                 if ('.' == answer[1])
 240                                         s++;
 241                                 else if ('\r' == answer[1] && '\n' == answer[2] && '\0' == answer[3])
 242                                         break;
 243                         }
 244                         //*strchrnul(s, '\r') = '\n';
 245                         fputs(s, fp);
 246                         free(answer);
 247                 }
 248
 249 #if ENABLE_FEATURE_POPMAILDIR_DELIVERY
 250                 // analyse delivery status
 251                 if (opts & (OPT_F|OPT_M)) {
 252                         rc = pclose(fp);
 253                         if (99 == rc) // 99 means bail out
 254                                 break;
 255 //                      if (rc) // !0 means skip to the next message
 256                                 goto skip;
 257 //                      // 0 means continue
 258                 } else {
 259                         // close filename
 260                         fclose(fp);
 261                 }
 262 #endif
 263
 264                 // delete message from server
 265                 if (!(opts & OPT_k))
 266                         pop3_check("DELE %u", (const char*)(ptrdiff_t)nmsg);
 267
 268                 // atomically move message to ./new/
 269                 target = xstrdup(filename);
 270                 memcpy(target, "new", 3);
 271                 // ... or just stop receiving on failure
 272                 if (rename_or_warn(filename, target))
 273                         break;
 274                 free(target);
 275
 276 #if ENABLE_FEATURE_POPMAILDIR_DELIVERY
 277  skip:
 278 #endif
 279                 free(filename);
 280         }
 281
 282         // Bye
 283         pop3_check("QUIT", NULL);
 284
 285         if (ENABLE_FEATURE_CLEAN_UP) {
 286                 free(G.user);
 287                 free(G.pass);
 288         }
 289
 290         return EXIT_SUCCESS;
 291 }