Denis Vlasenko | ddd42cb | 2008-01-29 00:59:15 +0000 | [diff] [blame^] | 1 | /* vi: set sw=4 ts=4: */ |
| 2 | /* |
| 3 | * bare bones sendmail |
| 4 | * |
| 5 | * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com> |
| 6 | * |
| 7 | * Licensed under GPLv2, see file LICENSE in this tarball for details. |
| 8 | */ |
| 9 | #include "libbb.h" |
| 10 | |
| 11 | /* |
| 12 | Extracted from BB uuencode.c |
| 13 | */ |
| 14 | enum { |
| 15 | SRC_BUF_SIZE = 45, /* This *MUST* be a multiple of 3 */ |
| 16 | DST_BUF_SIZE = 4 * ((SRC_BUF_SIZE + 2) / 3), |
| 17 | }; |
| 18 | |
| 19 | static void uuencode(const char *fname) |
| 20 | { |
| 21 | int fd; |
| 22 | char src_buf[SRC_BUF_SIZE]; |
| 23 | char dst_buf[1 + DST_BUF_SIZE + 1]; |
| 24 | |
| 25 | fd = xopen(fname, O_RDONLY); |
| 26 | fflush(stdout); |
| 27 | dst_buf[0] = '\n'; |
| 28 | while (1) { |
| 29 | size_t size = full_read(fd, src_buf, SRC_BUF_SIZE); |
| 30 | if (!size) |
| 31 | break; |
| 32 | if ((ssize_t)size < 0) |
| 33 | bb_perror_msg_and_die(bb_msg_read_error); |
| 34 | /* Encode the buffer we just read in */ |
| 35 | bb_uuencode(dst_buf + 1, src_buf, size, bb_uuenc_tbl_base64); |
| 36 | xwrite(STDOUT_FILENO, dst_buf, 1 + 4 * ((size + 2) / 3)); |
| 37 | } |
| 38 | close(fd); |
| 39 | } |
| 40 | |
| 41 | // "inline" version |
| 42 | // encodes content of given buffer instead of fd |
| 43 | // used to encode subject and authentication terms |
| 44 | static void uuencode_inline(const char *src_buf) |
| 45 | { |
| 46 | size_t len; |
| 47 | char dst_buf[DST_BUF_SIZE + 1]; |
| 48 | |
| 49 | len = strlen(src_buf); |
| 50 | fflush(stdout); |
| 51 | while (len > 0) { |
| 52 | size_t chunk = (len <= SRC_BUF_SIZE) ? len : SRC_BUF_SIZE; |
| 53 | bb_uuencode(dst_buf, src_buf, chunk, bb_uuenc_tbl_base64); |
| 54 | xwrite(STDOUT_FILENO, dst_buf, 4 * ((chunk + 2) / 3)); |
| 55 | src_buf += chunk; |
| 56 | len -= chunk; |
| 57 | } |
| 58 | } |
| 59 | |
| 60 | #if ENABLE_FEATURE_SENDMAIL_NETWORK |
| 61 | // generic signal handler |
| 62 | static void signal_handler(int signo) |
| 63 | { |
| 64 | int err; |
| 65 | |
| 66 | if (SIGALRM == signo) |
| 67 | bb_error_msg_and_die("timed out"); |
| 68 | |
| 69 | // SIGCHLD. reap zombies |
| 70 | if (wait_any_nohang(&err) > 0) |
| 71 | if (WIFEXITED(err) && WEXITSTATUS(err)) |
| 72 | bb_error_msg_and_die("child exited (%d)", WEXITSTATUS(err)); |
| 73 | } |
| 74 | |
| 75 | static pid_t helper_pid = -1; |
| 76 | |
| 77 | // read stdin, parses first bytes to a number, i.e. server response |
| 78 | // if code = -1 then just return this number |
| 79 | // if code != -1 then checks whether the number equals the code |
| 80 | // if not equal -> die saying errmsg |
| 81 | static int check(int code, const char *errmsg) |
| 82 | { |
| 83 | char *answer; |
| 84 | |
| 85 | // read a string and match it against the set of available answers |
| 86 | fflush(stdout); |
| 87 | answer = xmalloc_getline(stdin); |
| 88 | if (answer) { |
| 89 | int n = atoi(answer); |
| 90 | if (-1 == code || n == code) { |
| 91 | free(answer); |
| 92 | return n; |
| 93 | } |
| 94 | } |
| 95 | // TODO!!!: is there more elegant way to terminate child on program failure? |
| 96 | if (helper_pid > 0) |
| 97 | kill(helper_pid, SIGTERM); |
| 98 | if (!answer) |
| 99 | answer = (char*)"EOF"; |
| 100 | else |
| 101 | *strchrnul(answer, '\r') = '\0'; |
| 102 | bb_error_msg_and_die("error at %s: got '%s' instead", errmsg, answer); |
| 103 | } |
| 104 | |
| 105 | static int puts_and_check(const char *msg, int code, const char *errmsg) |
| 106 | { |
| 107 | puts(msg); |
| 108 | return check(code, errmsg); |
| 109 | } |
| 110 | #endif |
| 111 | |
| 112 | int sendmail_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| 113 | int sendmail_main(int argc, char **argv) |
| 114 | { |
| 115 | llist_t *recipients = NULL; |
| 116 | llist_t *bodies = NULL; |
| 117 | llist_t *attachments = NULL; |
| 118 | const char *from; |
| 119 | const char *notify; |
| 120 | const char *subject; |
| 121 | const char *charset = "utf-8"; |
| 122 | #if ENABLE_FEATURE_SENDMAIL_NETWORK |
| 123 | const char *wsecs = "10"; |
| 124 | const char *server = "127.0.0.1"; |
| 125 | const char *port = NULL; |
| 126 | const char *opt_user; |
| 127 | const char *opt_pass; |
| 128 | unsigned timeout; |
| 129 | #endif |
| 130 | char *boundary; |
| 131 | unsigned opts; |
| 132 | enum { |
| 133 | OPT_f = 1 << 0, // sender |
| 134 | OPT_n = 1 << 2, // notification |
| 135 | OPT_s = 1 << 3, // subject given |
| 136 | OPT_d = 1 << 7, // dry run - no networking |
| 137 | OPT_w = 1 << 8, // network timeout |
| 138 | OPT_h = 1 << 9, // server |
| 139 | OPT_p = 1 << 10, // port |
| 140 | OPT_U = 1 << 11, // user specified |
| 141 | OPT_P = 1 << 12, // password specified |
| 142 | }; |
| 143 | |
| 144 | // -f must be specified |
| 145 | // -t, -b, -a may be multiple |
| 146 | opt_complementary = "f:t::b::a::"; |
| 147 | opts = getopt32(argv, |
| 148 | "f:t:n::s:b:a:c:" USE_FEATURE_SENDMAIL_NETWORK("dw:h:p:U:P:"), |
| 149 | &from, &recipients, ¬ify, &subject, &bodies, &attachments, &charset |
| 150 | USE_FEATURE_SENDMAIL_NETWORK(, &wsecs, &server, &port, &opt_user, &opt_pass) |
| 151 | ); |
| 152 | //argc -= optind; |
| 153 | argv += optind; |
| 154 | |
| 155 | //printf("OPTS[%4x]\n", opts); |
| 156 | |
| 157 | // TODO!!!: strip recipients and sender from <> |
| 158 | |
| 159 | // establish connection |
| 160 | #if ENABLE_FEATURE_SENDMAIL_NETWORK |
| 161 | timeout = xatou(wsecs); |
| 162 | if (!(opts & OPT_d)) { |
| 163 | // ask password if we need to and while we're still have terminal |
| 164 | // TODO: get password directly from /dev/tty? or from a secret file? |
| 165 | if ((opts & (OPT_U+OPT_P)) == OPT_U) { |
| 166 | if (!isatty(STDIN_FILENO) || !(opt_pass = bb_askpass(0, "Password: "))) { |
| 167 | bb_error_msg_and_die("no password"); |
| 168 | } |
| 169 | } |
| 170 | //printf("OPTS[%4x][%s][%s]\n", opts, opt_user, opt_pass); |
| 171 | //exit(0); |
| 172 | // set chat timeout |
| 173 | alarm(timeout); |
| 174 | // connect to server |
| 175 | if (argv[0]) { |
| 176 | // if connection helper given |
| 177 | // setup vanilla unidirectional pipes interchange |
| 178 | int pipes[4]; |
| 179 | xpipe(pipes); |
| 180 | xpipe(pipes+2); |
| 181 | helper_pid = vfork(); |
| 182 | if (helper_pid < 0) |
| 183 | bb_perror_msg_and_die("vfork"); |
| 184 | xdup2(pipes[(helper_pid)?0:2], STDIN_FILENO); |
| 185 | xdup2(pipes[(helper_pid)?3:1], STDOUT_FILENO); |
| 186 | if (ENABLE_FEATURE_CLEAN_UP) |
| 187 | for (int i = 4; --i >= 0; ) |
| 188 | if (pipes[i] > STDOUT_FILENO) |
| 189 | close(pipes[i]); |
| 190 | // replace child with connection helper |
| 191 | if (!helper_pid) { |
| 192 | // child - try to execute connection helper |
| 193 | BB_EXECVP(argv[0], argv); |
| 194 | _exit(127); |
| 195 | } |
| 196 | // parent - check whether child is alive |
| 197 | sig_catch(SIGCHLD, signal_handler); |
| 198 | sig_catch(SIGALRM, signal_handler); |
| 199 | signal_handler(SIGCHLD); |
| 200 | // child seems OK -> parent goes on SMTP chat |
| 201 | } else { |
| 202 | // no connection helper provided -> make plain connect |
| 203 | int fd = create_and_connect_stream_or_die( |
| 204 | server, |
| 205 | bb_lookup_port(port, "tcp", 25) |
| 206 | ); |
| 207 | xmove_fd(fd, STDIN_FILENO); |
| 208 | xdup2(STDIN_FILENO, STDOUT_FILENO); |
| 209 | // wait for OK |
| 210 | check(220, "INIT"); |
| 211 | } |
| 212 | // mail user specified? try modern AUTHentication |
| 213 | if (opt_user && (334 == puts_and_check("auth login", -1, "auth login"))) { |
| 214 | uuencode_inline(opt_user); |
| 215 | puts_and_check("", 334, "AUTH"); |
| 216 | uuencode_inline(opt_pass); |
| 217 | puts_and_check("", 235, "AUTH"); |
| 218 | // no mail user specified or modern AUTHentication is not supported? |
| 219 | } else { |
| 220 | // fallback to simple HELO authentication |
| 221 | // fetch domain name (defaults to local) |
| 222 | const char *domain = strchr(from, '@'); |
| 223 | if (domain) |
| 224 | domain++; |
| 225 | else |
| 226 | domain = "local"; |
| 227 | printf("helo %s\n", domain); |
| 228 | check(250, "HELO"); |
| 229 | } |
| 230 | |
| 231 | // set addresses |
| 232 | printf("mail from:<%s>\n", from); |
| 233 | check(250, "MAIL FROM"); |
| 234 | for (llist_t *to = recipients; to; to = to->link) { |
| 235 | printf("rcpt to:<%s>\n", to->data); |
| 236 | check(250, "RCPT TO"); |
| 237 | } |
| 238 | puts_and_check("data", 354, "DATA"); |
| 239 | // no timeout while sending message |
| 240 | alarm(0); |
| 241 | } |
| 242 | #endif |
| 243 | |
| 244 | // now put message |
| 245 | // put address headers |
| 246 | printf("From: %s\n", from); |
| 247 | for (llist_t *to = recipients; to; to = to->link) { |
| 248 | printf("To: %s\n", to->data); |
| 249 | } |
| 250 | // put encoded subject |
| 251 | if (opts & OPT_s) { |
| 252 | printf("Subject: =?%s?B?", charset); |
| 253 | uuencode_inline(subject); |
| 254 | puts("?="); |
| 255 | } |
| 256 | // put notification |
| 257 | if (opts & OPT_n) { |
| 258 | const char *s = notify; |
| 259 | if (!s[0]) |
| 260 | s = from; // notify sender by default |
| 261 | printf("Disposition-Notification-To: %s\n", s); |
| 262 | } |
| 263 | // put common headers and body start |
| 264 | //srand(?); |
| 265 | boundary = xasprintf("%d-%d-%d", rand(), rand(), rand()); |
| 266 | printf( |
| 267 | "X-Mailer: busybox " BB_VER " sendmail\n" |
| 268 | "X-Priority: 3\n" |
| 269 | "Message-ID: <%s>\n" |
| 270 | "Mime-Version: 1.0\n" |
| 271 | "Content-Type: multipart/mixed; boundary=\"%s\"\n" |
| 272 | "\n" |
| 273 | "--%s\n" |
| 274 | "Content-Type: text/plain; charset=%s\n" |
| 275 | "%s\n%s" |
| 276 | , boundary, boundary, boundary, charset |
| 277 | , "Content-Disposition: inline" |
| 278 | , "Content-Transfer-Encoding: base64\n" |
| 279 | ); |
| 280 | // put body(ies) |
| 281 | for (llist_t *f = bodies; f; f = f->link) { |
| 282 | uuencode(f->data); |
| 283 | } |
| 284 | // put attachment(s) |
| 285 | for (llist_t *f = attachments; f; f = f->link) { |
| 286 | printf( |
| 287 | "\n--%s\n" |
| 288 | "Content-Type: application/octet-stream\n" |
| 289 | "%s; filename=\"%s\"\n" |
| 290 | "%s" |
| 291 | , boundary |
| 292 | , "Content-Disposition: inline" |
| 293 | , bb_get_last_path_component_strip(f->data) |
| 294 | , "Content-Transfer-Encoding: base64\n" |
| 295 | ); |
| 296 | uuencode(f->data); |
| 297 | } |
| 298 | // put terminator |
| 299 | printf("\n--%s--\n\n", boundary); |
| 300 | if (ENABLE_FEATURE_CLEAN_UP) |
| 301 | free(boundary); |
| 302 | |
| 303 | #if ENABLE_FEATURE_SENDMAIL_NETWORK |
| 304 | // end message and say goodbye |
| 305 | if (!(opts & OPT_d)) { |
| 306 | alarm(timeout); |
| 307 | puts_and_check(".", 250, "BODY"); |
| 308 | puts_and_check("quit", 221, "QUIT"); |
| 309 | } |
| 310 | #endif |
| 311 | |
| 312 | return 0; |
| 313 | } |