/* vi: set sw=4 ts=4: */ /* * bare bones sendmail * * Copyright (C) 2008 by Vladimir Dronnikov * * Licensed under GPLv2, see file LICENSE in this tarball for details. */ #include "libbb.h" /* Extracted from BB uuencode.c */ enum { SRC_BUF_SIZE = 45, /* This *MUST* be a multiple of 3 */ DST_BUF_SIZE = 4 * ((SRC_BUF_SIZE + 2) / 3), }; static void uuencode(const char *fname) { int fd; char src_buf[SRC_BUF_SIZE]; char dst_buf[1 + DST_BUF_SIZE + 1]; fd = xopen(fname, O_RDONLY); fflush(stdout); dst_buf[0] = '\n'; while (1) { size_t size = full_read(fd, src_buf, SRC_BUF_SIZE); if (!size) break; if ((ssize_t)size < 0) bb_perror_msg_and_die(bb_msg_read_error); /* Encode the buffer we just read in */ bb_uuencode(dst_buf + 1, src_buf, size, bb_uuenc_tbl_base64); xwrite(STDOUT_FILENO, dst_buf, 1 + 4 * ((size + 2) / 3)); } close(fd); } // "inline" version // encodes content of given buffer instead of fd // used to encode subject and authentication terms static void uuencode_inline(const char *src_buf) { size_t len; char dst_buf[DST_BUF_SIZE + 1]; len = strlen(src_buf); fflush(stdout); while (len > 0) { size_t chunk = (len <= SRC_BUF_SIZE) ? len : SRC_BUF_SIZE; bb_uuencode(dst_buf, src_buf, chunk, bb_uuenc_tbl_base64); xwrite(STDOUT_FILENO, dst_buf, 4 * ((chunk + 2) / 3)); src_buf += chunk; len -= chunk; } } #if ENABLE_FEATURE_SENDMAIL_NETWORK // generic signal handler static void signal_handler(int signo) { int err; if (SIGALRM == signo) bb_error_msg_and_die("timed out"); // SIGCHLD. reap zombies if (wait_any_nohang(&err) > 0) if (WIFEXITED(err) && WEXITSTATUS(err)) bb_error_msg_and_die("child exited (%d)", WEXITSTATUS(err)); } static pid_t helper_pid = -1; // read stdin, parses first bytes to a number, i.e. server response // if code = -1 then just return this number // if code != -1 then checks whether the number equals the code // if not equal -> die saying errmsg static int check(int code, const char *errmsg) { char *answer; // read a string and match it against the set of available answers fflush(stdout); answer = xmalloc_getline(stdin); if (answer) { int n = atoi(answer); if (-1 == code || n == code) { free(answer); return n; } } // TODO!!!: is there more elegant way to terminate child on program failure? if (helper_pid > 0) kill(helper_pid, SIGTERM); if (!answer) answer = (char*)"EOF"; else *strchrnul(answer, '\r') = '\0'; bb_error_msg_and_die("error at %s: got '%s' instead", errmsg, answer); } static int puts_and_check(const char *msg, int code, const char *errmsg) { puts(msg); return check(code, errmsg); } #endif int sendmail_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int sendmail_main(int argc, char **argv) { llist_t *recipients = NULL; llist_t *bodies = NULL; llist_t *attachments = NULL; const char *from; const char *notify; const char *subject; const char *charset = "utf-8"; #if ENABLE_FEATURE_SENDMAIL_NETWORK const char *wsecs = "10"; const char *server = "127.0.0.1"; const char *port = NULL; const char *opt_user; const char *opt_pass; unsigned timeout; #endif char *boundary; unsigned opts; enum { OPT_f = 1 << 0, // sender OPT_n = 1 << 2, // notification OPT_s = 1 << 3, // subject given OPT_d = 1 << 7, // dry run - no networking OPT_w = 1 << 8, // network timeout OPT_h = 1 << 9, // server OPT_p = 1 << 10, // port OPT_U = 1 << 11, // user specified OPT_P = 1 << 12, // password specified }; // -f must be specified // -t, -b, -a may be multiple opt_complementary = "f:t::b::a::"; opts = getopt32(argv, "f:t:n::s:b:a:c:" USE_FEATURE_SENDMAIL_NETWORK("dw:h:p:U:P:"), &from, &recipients, ¬ify, &subject, &bodies, &attachments, &charset USE_FEATURE_SENDMAIL_NETWORK(, &wsecs, &server, &port, &opt_user, &opt_pass) ); //argc -= optind; argv += optind; //printf("OPTS[%4x]\n", opts); // TODO!!!: strip recipients and sender from <> // establish connection #if ENABLE_FEATURE_SENDMAIL_NETWORK timeout = xatou(wsecs); if (!(opts & OPT_d)) { // ask password if we need to and while we're still have terminal // TODO: get password directly from /dev/tty? or from a secret file? if ((opts & (OPT_U+OPT_P)) == OPT_U) { if (!isatty(STDIN_FILENO) || !(opt_pass = bb_askpass(0, "Password: "))) { bb_error_msg_and_die("no password"); } } //printf("OPTS[%4x][%s][%s]\n", opts, opt_user, opt_pass); //exit(0); // set chat timeout alarm(timeout); // connect to server if (argv[0]) { // if connection helper given // setup vanilla unidirectional pipes interchange int pipes[4]; xpipe(pipes); xpipe(pipes+2); helper_pid = vfork(); if (helper_pid < 0) bb_perror_msg_and_die("vfork"); xdup2(pipes[(helper_pid)?0:2], STDIN_FILENO); xdup2(pipes[(helper_pid)?3:1], STDOUT_FILENO); if (ENABLE_FEATURE_CLEAN_UP) for (int i = 4; --i >= 0; ) if (pipes[i] > STDOUT_FILENO) close(pipes[i]); // replace child with connection helper if (!helper_pid) { // child - try to execute connection helper BB_EXECVP(argv[0], argv); _exit(127); } // parent - check whether child is alive sig_catch(SIGCHLD, signal_handler); sig_catch(SIGALRM, signal_handler); signal_handler(SIGCHLD); // child seems OK -> parent goes on SMTP chat } else { // no connection helper provided -> make plain connect int fd = create_and_connect_stream_or_die( server, bb_lookup_port(port, "tcp", 25) ); xmove_fd(fd, STDIN_FILENO); xdup2(STDIN_FILENO, STDOUT_FILENO); // wait for OK check(220, "INIT"); } // mail user specified? try modern AUTHentication if (opt_user && (334 == puts_and_check("auth login", -1, "auth login"))) { uuencode_inline(opt_user); puts_and_check("", 334, "AUTH"); uuencode_inline(opt_pass); puts_and_check("", 235, "AUTH"); // no mail user specified or modern AUTHentication is not supported? } else { // fallback to simple HELO authentication // fetch domain name (defaults to local) const char *domain = strchr(from, '@'); if (domain) domain++; else domain = "local"; printf("helo %s\n", domain); check(250, "HELO"); } // set addresses printf("mail from:<%s>\n", from); check(250, "MAIL FROM"); for (llist_t *to = recipients; to; to = to->link) { printf("rcpt to:<%s>\n", to->data); check(250, "RCPT TO"); } puts_and_check("data", 354, "DATA"); // no timeout while sending message alarm(0); } #endif // now put message // put address headers printf("From: %s\n", from); for (llist_t *to = recipients; to; to = to->link) { printf("To: %s\n", to->data); } // put encoded subject if (opts & OPT_s) { printf("Subject: =?%s?B?", charset); uuencode_inline(subject); puts("?="); } // put notification if (opts & OPT_n) { const char *s = notify; if (!s[0]) s = from; // notify sender by default printf("Disposition-Notification-To: %s\n", s); } // put common headers and body start //srand(?); boundary = xasprintf("%d-%d-%d", rand(), rand(), rand()); printf( "X-Mailer: busybox " BB_VER " sendmail\n" "X-Priority: 3\n" "Message-ID: <%s>\n" "Mime-Version: 1.0\n" "Content-Type: multipart/mixed; boundary=\"%s\"\n" "\n" "--%s\n" "Content-Type: text/plain; charset=%s\n" "%s\n%s" , boundary, boundary, boundary, charset , "Content-Disposition: inline" , "Content-Transfer-Encoding: base64\n" ); // put body(ies) for (llist_t *f = bodies; f; f = f->link) { uuencode(f->data); } // put attachment(s) for (llist_t *f = attachments; f; f = f->link) { printf( "\n--%s\n" "Content-Type: application/octet-stream\n" "%s; filename=\"%s\"\n" "%s" , boundary , "Content-Disposition: inline" , bb_get_last_path_component_strip(f->data) , "Content-Transfer-Encoding: base64\n" ); uuencode(f->data); } // put terminator printf("\n--%s--\n\n", boundary); if (ENABLE_FEATURE_CLEAN_UP) free(boundary); #if ENABLE_FEATURE_SENDMAIL_NETWORK // end message and say goodbye if (!(opts & OPT_d)) { alarm(timeout); puts_and_check(".", 250, "BODY"); puts_and_check("quit", 221, "QUIT"); } #endif return 0; }