1 /* vi: set sw=4 ts=4: */
3 * bare bones sendmail/fetchmail
5 * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
7 * Licensed under GPLv2, see file LICENSE in this tarball for details.
11 #define INITIAL_STDIN_FILENO 3
13 static void uuencode(char *fname, const char *text)
16 SRC_BUF_SIZE = 45, /* This *MUST* be a multiple of 3 */
17 DST_BUF_SIZE = 4 * ((SRC_BUF_SIZE + 2) / 3),
23 char dst_buf[DST_BUF_SIZE + 1];
26 fd = INITIAL_STDIN_FILENO;
27 if (NOT_LONE_DASH(fname))
28 fd = xopen(fname, O_RDONLY);
29 src_buf = bb_common_bufsiz1;
30 // N.B. strlen(NULL) segfaults!
32 // though we do not call uuencode(NULL, NULL) explicitly
33 // still we do not want to break things suddenly
38 fflush(stdout); // sync stdio and unistd output
42 size = full_read(fd, (char *)src_buf, SRC_BUF_SIZE);
43 if ((ssize_t)size < 0)
44 bb_perror_msg_and_die(bb_msg_read_error);
47 if (len > SRC_BUF_SIZE)
52 // encode the buffer we just read in
53 bb_uuencode(dst_buf, src_buf, size, bb_uuenc_tbl_base64);
55 xwrite(STDOUT_FILENO, "\r\n", 2);
60 xwrite(STDOUT_FILENO, dst_buf, 4 * ((size + 2) / 3));
71 // arguments for SSL connection helper
73 // arguments for postprocess helper
76 #define G (*ptr_to_globals)
77 #define helper_pid (G.helper_pid)
78 #define timeout (G.timeout )
79 #define xargs (G.xargs )
80 #define fargs (G.fargs )
81 #define INIT_G() do { \
82 SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
83 xargs[0] = "openssl"; \
84 xargs[1] = "s_client"; \
85 xargs[2] = "-quiet"; \
86 xargs[3] = "-connect"; \
87 /*xargs[4] = "localhost";*/ \
89 xargs[6] = "-starttls"; \
94 #define opt_connect (xargs[4])
95 #define opt_after_connect (xargs[5])
96 #define opt_charset (fargs[0])
97 #define opt_subject (fargs[1])
99 static void kill_helper(void)
101 // TODO!!!: is there more elegant way to terminate child on program failure?
103 kill(helper_pid, SIGTERM);
106 // generic signal handler
107 static void signal_handler(int signo)
111 if (SIGALRM == signo) {
113 bb_error_msg_and_die("timed out");
116 // SIGCHLD. reap zombies
117 if (wait_any_nohang(&err) > 0)
118 if (WIFEXITED(err) && WEXITSTATUS(err))
119 bb_error_msg_and_die("child exited (%d)", WEXITSTATUS(err));
123 static void launch_helper(const char **argv)
125 // setup vanilla unidirectional pipes interchange
131 helper_pid = vfork();
133 bb_perror_msg_and_die("vfork");
134 idx = (!helper_pid) * 2;
135 xdup2(pipes[idx], STDIN_FILENO);
136 xdup2(pipes[3-idx], STDOUT_FILENO);
137 if (ENABLE_FEATURE_CLEAN_UP)
138 for (int i = 4; --i >= 0; )
139 if (pipes[i] > STDOUT_FILENO)
142 // child: try to execute connection helper
143 BB_EXECVP(*argv, (char **)argv);
146 // parent: check whether child is alive
151 signal_handler(SIGCHLD);
152 // child seems OK -> parent goes on
155 static const char *command(const char *fmt, const char *param)
157 const char *msg = fmt;
160 msg = xasprintf(fmt, param);
161 printf("%s\r\n", msg);
167 static int smtp_checkp(const char *fmt, const char *param, int code)
170 const char *msg = command(fmt, param);
172 // if the string has a form \d\d\d- -- read next string. E.g. EHLO response
173 // parse first bytes to a number
174 // if code = -1 then just return this number
175 // if code != -1 then checks whether the number equals the code
176 // if not equal -> die saying msg
177 while ((answer = xmalloc_fgetline(stdin)) != NULL)
178 if (strlen(answer) <= 3 || '-' != answer[3])
181 int n = atoi(answer);
183 if (ENABLE_FEATURE_CLEAN_UP) {
186 if (-1 == code || n == code) {
191 bb_error_msg_and_die("%s failed", msg);
194 static inline int smtp_check(const char *fmt, int code)
196 return smtp_checkp(fmt, NULL, code);
199 // strip argument of bad chars
200 static char *sane(char *str)
205 if (isalnum(*s) || '_' == *s || '-' == *s || '.' == *s || '@' == *s) {
215 static void pop3_checkr(const char *fmt, const char *param, char **ret)
217 const char *msg = command(fmt, param);
218 char *answer = xmalloc_fgetline(stdin);
219 if (answer && '+' == *answer) {
222 *ret = answer+4; // skip "+OK "
223 else if (ENABLE_FEATURE_CLEAN_UP)
228 bb_error_msg_and_die("%s failed", msg);
231 static inline void pop3_check(const char *fmt, const char *param)
233 pop3_checkr(fmt, param, NULL);
236 static void pop3_message(const char *filename)
240 // create and open file filename
241 // read stdin, copy to created file
242 fd = xopen(filename, O_CREAT | O_WRONLY | O_TRUNC | O_EXCL);
243 while ((answer = xmalloc_fgets_str(stdin, "\r\n")) != NULL) {
245 if ('.' == *answer) {
246 if ('.' == answer[1])
248 else if ('\r' == answer[1] && '\n' == answer[2] && '\0' == answer[3])
251 xwrite(fd, s, strlen(s));
258 static char *parse_url(char *url, char **user, char **pass)
260 // parse [user[:pass]@]host
262 char *s = strchr(url, '@');
263 *user = *pass = NULL;
268 s = strchr(*user, ':');
277 int sendgetmail_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
278 int sendgetmail_main(int argc ATTRIBUTE_UNUSED, char **argv)
280 llist_t *opt_recipients = NULL;
281 llist_t *opt_attachments = NULL;
286 OPT_w = 1 << 0, // network timeout
287 OPT_H = 1 << 1, // [user:password@]server[:port]
288 OPT_S = 1 << 2, // connect using openssl s_client helper
290 OPTS_t = 1 << 3, // sendmail: read addresses from body
291 OPTF_t = 1 << 3, // fetchmail: use "TOP" not "RETR"
293 OPTS_s = 1 << 4, // sendmail: subject
294 OPTF_z = 1 << 4, // fetchmail: delete from server
296 OPTS_c = 1 << 5, // sendmail: assumed charset
297 OPTS_a = 1 << 6, // sendmail: attachment(s)
298 OPTS_i = 1 << 7, // sendmail: ignore lone dots in message body (implied)
300 OPTS_N = 1 << 8, // sendmail: request notification
301 OPTS_f = 1 << 9, // sendmail: sender address
306 // init global variables
309 // parse options, different option sets for sendmail and fetchmail
310 // N.B. opt_after_connect hereafter is NULL if we are called as fetchmail
311 // and is NOT NULL if we are called as sendmail
312 if (!ENABLE_FETCHMAIL || 's' == applet_name[0]) {
314 // save initial stdin since body is piped!
315 xdup2(STDIN_FILENO, INITIAL_STDIN_FILENO);
316 opt_complementary = "w+:a::";
317 options = "w:H:St" "s:c:a:iN:f:";
318 // body is pseudo attachment read from stdin
319 llist_add_to_end(&opt_attachments, (char *)"-");
322 opt_after_connect = NULL;
323 opt_complementary = "-1:w+";
324 options = "w:H:St" "z";
326 opts = getopt32(argv, options,
327 &timeout /* -w */, &opt_connect /* -H */,
328 &opt_subject, &opt_charset, &opt_attachments, NULL, &opt_from
334 // host[:port] not specified ? -> use $HOSTNAME. no $HOSTNAME ? -> use localhost
335 if (!(opts & OPT_H)) {
336 opt_connect = getenv("HOSTNAME");
338 opt_connect = "127.0.0.1";
340 // fetch username and password, if any
341 // NB: parse_url modifies opt_connect[] ONLY if '@' is there.
342 // Thus "127.0.0.1" won't be modified, an is ok that it is RO.
343 opt_connect = parse_url((char*)opt_connect, &opt_user, &opt_pass);
344 // bb_error_msg("H[%s] U[%s] P[%s]", opt_connect, opt_user, opt_pass);
346 // username must be defined!
348 // N.B. IMHO getenv("USER") can be way easily spoofed!
349 opt_user = bb_getpwuid(NULL, -1, getuid());
354 // ... use openssl helper
355 launch_helper(xargs);
356 // no SSL ordered? ->
358 // ... make plain connect
359 int fd = create_and_connect_stream_or_die(opt_connect, 25);
360 // make ourselves a simple IO filter
361 // from now we know nothing about network :)
362 xmove_fd(fd, STDIN_FILENO);
363 xdup2(STDIN_FILENO, STDOUT_FILENO);
367 if (!ENABLE_FETCHMAIL || opt_after_connect)
368 /***************************************************
370 ***************************************************/
379 // recipients specified as arguments
381 // loose test on email address validity
382 if (strchr(sane(*argv), '@'))
383 llist_add_to_end(&opt_recipients, *argv);
387 // if -t specified or no recipients specified -> enter all-included mode
388 // i.e. scan stdin for To: and Subject: lines ...
389 // ... and then use the rest of stdin as message body
390 // N.B. subject read from body has priority
391 // over that specified on command line.
392 // recipients are merged
393 if (opts & OPTS_t || !opt_recipients) {
394 // fetch recipients and (optionally) subject
396 while ((s = xmalloc_reads(INITIAL_STDIN_FILENO, NULL, NULL)) != NULL) {
397 if (0 == strncmp("To: ", s, 4)) {
398 llist_add_to_end(&opt_recipients, s+4);
399 /* } else if (0 == strncmp("From: ", s, 6)) {
402 */ } else if (0 == strncmp("Subject: ", s, 9)) {
414 // got no sender address? -> use username as a resort
415 if (!(opts & OPTS_f)) {
416 char *domain = safe_getdomainname();
417 opt_from = xasprintf("%s@%s", opt_user, domain);
421 // introduce to server
423 // we didn't use SSL helper? ->
424 if (!(opts & OPT_S)) {
425 // ... wait for initial server OK
426 smtp_check(NULL, 220);
429 // we should start with modern EHLO
430 if (250 != smtp_checkp("EHLO %s", sane(opt_from), -1)) {
431 smtp_checkp("HELO %s", opt_from, 250);
435 // NOTE: if password has not been specified
436 // then no authentication is possible
437 code = (opt_pass) ? -1 : 250;
438 // first try softly without authentication
439 while (250 != smtp_checkp("MAIL FROM:<%s>", opt_from, code)) {
440 // MAIL FROM failed -> authentication needed
441 if (334 == smtp_check("AUTH LOGIN", -1)) {
442 uuencode(NULL, opt_user); // opt_user != NULL
444 uuencode(NULL, opt_pass);
447 // authenticated OK? -> retry to set sender
448 // but this time die on failure!
453 for (l = opt_recipients; l; l = l->link) {
454 smtp_checkp("RCPT TO:<%s>", sane(l->data), 250);
457 // enter "put message" mode
458 smtp_check("DATA", 354);
460 // put address headers
461 printf("From: %s\r\n", opt_from);
462 for (l = opt_recipients; l; l = l->link) {
463 printf("To: %s\r\n", l->data);
466 // put encoded subject
468 sane((char *)opt_charset);
470 printf("Subject: =?%s?B?", opt_charset);
471 uuencode(NULL, opt_subject);
477 printf("Disposition-Notification-To: %s\r\n", opt_from);
479 // make a random string -- it will delimit message parts
480 srand(monotonic_us());
481 boundary = xasprintf("%d-%d-%d", rand(), rand(), rand());
483 // put common headers and body start
485 "Message-ID: <%s>\r\n"
486 "Mime-Version: 1.0\r\n"
487 "%smultipart/mixed; boundary=\"%s\"\r\n"
493 // put body + attachment(s)
494 // N.B. all these weird things just to be tiny
495 // by reusing string patterns!
498 "%stext/plain; charset=%s\r\n"
511 , "Content-Disposition: inline"
513 , "Content-Transfer-Encoding: base64\r\n"
518 "%sapplication/octet-stream%s\r\n"
519 "%s; filename=\"%s\"\r\n"
522 uuencode(l->data, NULL);
525 q = bb_get_last_path_component_strip(l->data);
528 // put message terminator
529 printf("\r\n--%s--\r\n" "\r\n", boundary);
531 // leave "put message" mode
532 smtp_check(".", 250);
533 // ... and say goodbye
534 smtp_check("QUIT", 221);
537 /***************************************************
539 ***************************************************/
546 // cache fetch command:
547 // TOP will return only the headers
548 // RETR will dump the whole message
549 const char *retr = (opts & OPTF_t) ? "TOP %u 0" : "RETR %u";
554 // cache postprocess program
559 // password is mandatory
561 bb_error_msg_and_die("no password");
564 // get server greeting
565 pop3_checkr(NULL, NULL, &buf);
567 // server supports APOP?
570 // yes! compose <stamp><password>
571 char *s = strchr(buf, '>');
573 strcpy(s+1, opt_pass);
575 // get md5 sum of <stamp><password>
577 md5_hash(s, strlen(s), &md5);
579 // NOTE: md5 struct contains enough space
580 // so we reuse md5 space instead of xzalloc(16*2+1)
581 #define md5_hex ((uint8_t *)&md5)
582 // uint8_t *md5_hex = (uint8_t *)&md5;
583 *bin2hex((char *)md5_hex, s, 16) = '\0';
585 s = xasprintf("%s %s", opt_user, md5_hex);
587 pop3_check("APOP %s", s);
588 if (ENABLE_FEATURE_CLEAN_UP) {
590 free(buf-4); // buf is "+OK " away from malloc'ed string
592 // server ignores APOP -> use simple text authentication
595 pop3_check("USER %s", opt_user);
597 pop3_check("PASS %s", opt_pass);
600 // get mailbox statistics
601 pop3_checkr("STAT", NULL, &buf);
603 // prepare message filename suffix
604 hostname = safe_gethostname();
607 // get messages counter
608 // NOTE: we don't use xatou(buf) since buf is "nmsg nbytes"
609 // we only need nmsg and atoi is just exactly what we need
610 // if atoi fails to convert buf into number it returns 0
611 // in this case the following loop simply will not be executed
613 if (ENABLE_FEATURE_CLEAN_UP)
614 free(buf-4); // buf is "+OK " away from malloc'ed string
616 // loop through messages
617 for (; nmsg; nmsg--) {
619 // generate unique filename
620 char *filename = xasprintf("tmp/%llu.%u.%s",
621 monotonic_us(), (unsigned)pid, hostname);
625 // retrieve message in ./tmp/
626 pop3_check(retr, (const char *)(ptrdiff_t)nmsg);
627 pop3_message(filename);
628 // delete message from server
630 pop3_check("DELE %u", (const char*)(ptrdiff_t)nmsg);
632 // run postprocessing program
635 rc = wait4pid(spawn((char **)fargs));
642 // atomically move message to ./new/
643 target = xstrdup(filename);
644 strncpy(target, "new", 3);
645 // ... or just stop receiving on error
646 if (rename_or_warn(filename, target))
654 pop3_check("QUIT", NULL);
656 #endif // ENABLE_FETCHMAIL