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));
69 // arguments for SSL connection helper
71 // arguments for postprocess helper
74 #define G (*ptr_to_globals)
75 #define helper_pid (G.helper_pid)
76 #define timeout (G.timeout )
77 #define xargs (G.xargs )
78 #define fargs (G.fargs )
79 #define INIT_G() do { \
80 SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
81 xargs[0] = "openssl"; \
82 xargs[1] = "s_client"; \
83 xargs[2] = "-quiet"; \
84 xargs[3] = "-connect"; \
85 /*xargs[4] = "server[:port]";*/ \
87 xargs[6] = "-starttls"; \
92 #define opt_connect (xargs[4])
93 #define opt_after_connect (xargs[5])
94 #define opt_charset (fargs[0])
95 #define opt_subject (fargs[1])
97 static void kill_helper(void)
99 // TODO!!!: is there more elegant way to terminate child on program failure?
101 kill(helper_pid, SIGTERM);
104 // generic signal handler
105 static void signal_handler(int signo)
109 if (SIGALRM == signo) {
111 bb_error_msg_and_die("timed out");
114 // SIGCHLD. reap zombies
115 if (wait_any_nohang(&err) > 0)
116 if (WIFEXITED(err) && WEXITSTATUS(err))
117 bb_error_msg_and_die("child exited (%d)", WEXITSTATUS(err));
120 static void launch_helper(const char **argv)
122 // setup vanilla unidirectional pipes interchange
127 helper_pid = vfork();
129 bb_perror_msg_and_die("vfork");
130 idx = (!helper_pid)*2;
131 xdup2(pipes[idx], STDIN_FILENO);
132 xdup2(pipes[3-idx], STDOUT_FILENO);
133 if (ENABLE_FEATURE_CLEAN_UP)
134 for (int i = 4; --i >= 0; )
135 if (pipes[i] > STDOUT_FILENO)
138 // child: try to execute connection helper
139 BB_EXECVP(*argv, (char **)argv);
142 // parent: check whether child is alive
147 signal_handler(SIGCHLD);
148 // child seems OK -> parent goes on
151 static const char *command(const char *fmt, const char *param)
153 const char *msg = fmt;
156 msg = xasprintf(fmt, param);
157 printf("%s\r\n", msg);
163 static int smtp_checkp(const char *fmt, const char *param, int code)
166 const char *msg = command(fmt, param);
168 // if the string has a form \d\d\d- -- read next string. E.g. EHLO response
169 // parse first bytes to a number
170 // if code = -1 then just return this number
171 // if code != -1 then checks whether the number equals the code
172 // if not equal -> die saying msg
173 while ((answer = xmalloc_getline(stdin)) != NULL)
174 if (strlen(answer) <= 3 || '-' != answer[3])
177 int n = atoi(answer);
179 if (ENABLE_FEATURE_CLEAN_UP) {
182 if (-1 == code || n == code) {
187 bb_error_msg_and_die("%s failed", msg);
190 static int inline smtp_check(const char *fmt, int code)
192 return smtp_checkp(fmt, NULL, code);
195 // strip argument of bad chars
196 static char *sane(char *str)
201 if (isalnum(*s) || '_' == *s || '-' == *s || '.' == *s || '@' == *s) {
211 static void pop3_checkr(const char *fmt, const char *param, char **ret)
213 const char *msg = command(fmt, param);
214 char *answer = xmalloc_getline(stdin);
215 if (answer && '+' == *answer) {
218 *ret = answer+4; // skip "+OK "
219 else if (ENABLE_FEATURE_CLEAN_UP)
224 bb_error_msg_and_die("%s failed", msg);
227 static void inline pop3_check(const char *fmt, const char *param)
229 pop3_checkr(fmt, param, NULL);
232 static void pop3_message(const char *filename)
236 // create and open file filename
237 // read stdin, copy to created file
238 fd = xopen(filename, O_CREAT | O_WRONLY | O_TRUNC | O_EXCL);
239 while ((answer = xmalloc_fgets_str(stdin, "\r\n")) != NULL) {
241 if ('.' == *answer) {
242 if ('.' == answer[1])
244 else if ('\r' == answer[1] && '\n' == answer[2] && '\0' == answer[3])
247 xwrite(fd, s, strlen(s));
254 int sendgetmail_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
255 int sendgetmail_main(int argc ATTRIBUTE_UNUSED, char **argv)
257 llist_t *opt_recipients = NULL;
259 const char *opt_user;
260 const char *opt_pass;
263 OPT_w = 1 << 0, // network timeout
264 OPT_U = 1 << 1, // user
265 OPT_P = 1 << 2, // password
266 OPT_X = 1 << 3, // connect using openssl s_client helper
268 OPTS_n = 1 << 4, // sendmail: request notification
269 OPTF_t = 1 << 4, // fetchmail: use "TOP" not "RETR"
271 OPTS_s = 1 << 5, // sendmail: subject
272 OPTF_z = 1 << 5, // fetchmail: delete from server
274 OPTS_c = 1 << 6, // sendmail: assumed charset
275 OPTS_t = 1 << 7, // sendmail: recipient(s)
281 // init global variables
284 // parse options, different option sets for sendmail and fetchmail
285 // N.B. opt_after_connect hereafter is NULL if we are called as fetchmail
286 // and is NOT NULL if we are called as sendmail
287 if (!ENABLE_FETCHMAIL || 's' == applet_name[0]) {
289 // save initial stdin (body or attachements can be piped!)
290 xdup2(STDIN_FILENO, INITIAL_STDIN_FILENO);
291 opt_complementary = "-2:w+:t:t::"; // count(-t) > 0
292 options = "w:U:P:X" "ns:c:t:";
295 opt_after_connect = NULL;
296 opt_complementary = "-2:w+:P";
297 options = "w:U:P:X" "tz";
299 opts = getopt32(argv, options,
300 &timeout, &opt_user, &opt_pass,
301 &opt_subject, &opt_charset, &opt_recipients
306 // first argument is remote server[:port]
307 opt_connect = *argv++;
312 // ... use openssl helper
313 launch_helper(xargs);
314 // no SSL ordered? ->
316 // ... make plain connect
317 int fd = create_and_connect_stream_or_die(opt_connect, 25);
318 // make ourselves a simple IO filter
319 // from now we know nothing about network :)
320 xmove_fd(fd, STDIN_FILENO);
321 xdup2(STDIN_FILENO, STDOUT_FILENO);
326 if (opt_after_connect)
329 /***************************************************
331 ***************************************************/
340 // we didn't use SSL helper? ->
341 if (!(opts & OPT_X)) {
342 // ... wait for initial server OK
343 smtp_check(NULL, 220);
347 opt_from = sane(*argv++);
349 // introduce to server
350 // we should start with modern EHLO
351 if (250 != smtp_checkp("EHLO %s", opt_from, -1)) {
352 smtp_checkp("HELO %s", opt_from, 250);
356 // NOTE: if password has not been specified
357 // then no authentication is possible
358 code = (opts & OPT_P) ? -1 : 250;
359 // first try softly without authentication
360 while (250 != smtp_checkp("MAIL FROM:<%s>", opt_from, code)) {
361 // MAIL FROM failed -> authentication needed
362 // have we got username?
363 if (!(opts & OPT_U)) {
364 // no! fetch it from "from" option
366 opt_user = xstrdup(opt_from);
367 *strchrnul(opt_user, '@') = '\0';
369 // now we've got username
370 // so try to authenticate
371 if (334 == smtp_check("AUTH LOGIN", -1)) {
372 uuencode(NULL, opt_user);
374 uuencode(NULL, opt_pass);
377 // authenticated OK? -> retry to set sender
378 // but this time die on failure!
383 for (llist_t *to = opt_recipients; to; to = to->link) {
384 smtp_checkp("RCPT TO:<%s>", sane(to->data), 250);
387 // enter "put message" mode
388 smtp_check("DATA", 354);
390 // put address headers
391 printf("From: %s\r\n", opt_from);
392 for (llist_t *to = opt_recipients; to; to = to->link) {
393 printf("To: %s\r\n", to->data);
396 // put encoded subject
398 sane((char *)opt_charset);
400 printf("Subject: =?%s?B?", opt_charset);
401 uuencode(NULL, opt_subject);
407 printf("Disposition-Notification-To: %s\r\n", opt_from);
409 // make a random string -- it will delimit message parts
410 srand(monotonic_us());
411 boundary = xasprintf("%d-%d-%d", rand(), rand(), rand());
413 // put common headers and body start
415 "Message-ID: <%s>\r\n"
416 "Mime-Version: 1.0\r\n"
417 "%smultipart/mixed; boundary=\"%s\"\r\n"
423 // put body + attachment(s)
424 // N.B. all these weird things just to be tiny
425 // by reusing string patterns!
428 "%stext/plain; charset=%s\r\n"
440 , "Content-Disposition: inline"
442 , "Content-Transfer-Encoding: base64\r\n"
447 "%sapplication/octet-stream%s\r\n"
448 "%s; filename=\"%s\"\r\n"
451 uuencode(*argv, NULL);
453 q = bb_get_last_path_component_strip(*argv);
456 // put message terminator
457 printf("\r\n--%s--\r\n" "\r\n", boundary);
459 // leave "put message" mode
460 smtp_check(".", 250);
461 // ... and say goodbye
462 smtp_check("QUIT", 221);
466 /***************************************************
468 ***************************************************/
475 // cache fetch command:
476 // TOP will return only the headers
477 // RETR will dump the whole message
478 const char *retr = (opts & OPTF_t) ? "TOP %u 0" : "RETR %u";
483 // cache postprocess program
487 if (!(opts & OPT_U)) {
489 // N.B. IMHO getenv("USER") can be way easily spoofed!
490 opt_user = bb_getpwuid(NULL, -1, getuid());
493 // get server greeting
494 pop3_checkr(NULL, NULL, &buf);
496 // server supports APOP?
499 // yes! compose <stamp><password>
500 char *s = strchr(buf, '>');
502 strcpy(s+1, opt_pass);
504 // get md5 sum of <stamp><password>
506 md5_hash(s, strlen(s), &md5);
508 // NOTE: md5 struct contains enough space
509 // so we reuse md5 space instead of xzalloc(16*2+1)
510 #define md5_hex ((uint8_t *)&md5)
511 // uint8_t *md5_hex = (uint8_t *)&md5;
512 *bin2hex(md5_hex, s, 16) = '\0';
514 s = xasprintf("%s %s", opt_user, md5_hex);
516 pop3_check("APOP %s", s);
517 if (ENABLE_FEATURE_CLEAN_UP) {
519 free(buf-4); // buf is "+OK " away from malloc'ed string
521 // server ignores APOP -> use simple text authentication
524 pop3_check("USER %s", opt_user);
526 pop3_check("PASS %s", opt_pass);
529 // get mailbox statistics
530 pop3_checkr("STAT", NULL, &buf);
532 // prepare message filename suffix
533 hostname = safe_gethostname();
536 // get messages counter
537 // NOTE: we don't use xatou(buf) since buf is "nmsg nbytes"
538 // we only need nmsg and atoi is just exactly what we need
539 // if atoi fails to convert buf into number it returns 0
540 // in this case the following loop simply will not be executed
542 if (ENABLE_FEATURE_CLEAN_UP)
543 free(buf-4); // buf is "+OK " away from malloc'ed string
545 // loop through messages
546 for (; nmsg; nmsg--) {
548 // generate unique filename
549 char *filename = xasprintf("tmp/%llu.%u.%s", monotonic_us(), pid, hostname);
553 // retrieve message in ./tmp/
554 pop3_check(retr, (const char *)(ptrdiff_t)nmsg);
555 pop3_message(filename);
556 // delete message from server
558 pop3_check("DELE %u", (const char*)(ptrdiff_t)nmsg);
560 // run postprocessing program
563 rc = wait4pid(spawn((char **)fargs));
570 // atomically move message to ./new/
571 target = xstrdup(filename);
572 strncpy(target, "new", 3);
573 // ... or just stop receiving on error
574 if (rename_or_warn(filename, target))
582 pop3_check("QUIT", NULL);
583 #endif // ENABLE_FETCHMAIL