busybox/mailutils/popmaildir.c
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   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 (10 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
  68static void pop3_checkr(const char *fmt, const char *param, char **ret)
  69{
  70        char *msg = send_mail_command(fmt, param);
  71        char *answer = xmalloc_fgetline(stdin);
  72        if (answer && '+' == answer[0]) {
  73                free(msg);
  74                if (timeout)
  75                        alarm(0);
  76                if (ret) {
  77                        // skip "+OK "
  78                        memmove(answer, answer + 4, strlen(answer) - 4);
  79                        *ret = answer;
  80                } else
  81                        free(answer);
  82                return;
  83        }
  84        bb_error_msg_and_die("%s failed, reply was: %s", msg, answer);
  85}
  86
  87static void pop3_check(const char *fmt, const char *param)
  88{
  89        pop3_checkr(fmt, param, NULL);
  90}
  91
  92int popmaildir_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  93int popmaildir_main(int argc UNUSED_PARAM, char **argv)
  94{
  95        char *buf;
  96        unsigned nmsg;
  97        char *hostname;
  98        pid_t pid;
  99        const char *retr;
 100#if ENABLE_FEATURE_POPMAILDIR_DELIVERY
 101        const char *delivery;
 102#endif
 103        unsigned opt_nlines = 0;
 104
 105        enum {
 106                OPT_b = 1 << 0,         // -b binary mode. Ignored
 107                OPT_d = 1 << 1,         // -d,-dd,-ddd debug. Ignored
 108                OPT_m = 1 << 2,         // -m show used memory. Ignored
 109                OPT_V = 1 << 3,         // -V version. Ignored
 110                OPT_c = 1 << 4,         // -c use tcpclient. Ignored
 111                OPT_a = 1 << 5,         // -a use APOP protocol
 112                OPT_s = 1 << 6,         // -s skip authorization
 113                OPT_T = 1 << 7,         // -T get messages with TOP instead with RETR
 114                OPT_k = 1 << 8,         // -k keep retrieved messages on the server
 115                OPT_t = 1 << 9,         // -t90 set timeout to 90 sec
 116                OPT_R = 1 << 10,        // -R20000 remove old messages on the server >= 20000 bytes (requires -k). Ignored
 117                OPT_Z = 1 << 11,        // -Z11-23 remove messages from 11 to 23 (dangerous). Ignored
 118                OPT_L = 1 << 12,        // -L50000 not retrieve new messages >= 50000 bytes. Ignored
 119                OPT_H = 1 << 13,        // -H30 type first 30 lines of a message; (-L12000 -H30). Ignored
 120                OPT_M = 1 << 14,        // -M\"program arg1 arg2 ...\"; deliver by program. Treated like -F
 121                OPT_F = 1 << 15,        // -F\"program arg1 arg2 ...\"; filter by program. Treated like -M
 122        };
 123
 124        // init global variables
 125        INIT_G();
 126
 127        // parse options
 128        opts = getopt32(argv, "^"
 129                "bdmVcasTkt:+" "R:+Z:L:+H:+" IF_FEATURE_POPMAILDIR_DELIVERY("M:F:")
 130                "\0" "-1:dd",
 131                &timeout, NULL, NULL, NULL, &opt_nlines
 132                IF_FEATURE_POPMAILDIR_DELIVERY(, &delivery, &delivery) // we treat -M and -F the same
 133        );
 134        //argc -= optind;
 135        argv += optind;
 136
 137        // get auth info
 138        if (!(opts & OPT_s))
 139                get_cred_or_die(STDIN_FILENO);
 140
 141        // goto maildir
 142        xchdir(*argv++);
 143
 144        // launch connect helper, if any
 145        if (*argv)
 146                launch_helper((const char **)argv);
 147
 148        // get server greeting
 149        pop3_checkr(NULL, NULL, &buf);
 150
 151        // authenticate (if no -s given)
 152        if (!(opts & OPT_s)) {
 153                // server supports APOP and we want it?
 154                if ('<' == buf[0] && (opts & OPT_a)) {
 155                        union { // save a bit of stack
 156                                md5_ctx_t ctx;
 157                                char hex[16 * 2 + 1];
 158                        } md5;
 159                        uint32_t res[16 / 4];
 160
 161                        char *s = strchr(buf, '>');
 162                        if (s)
 163                                s[1] = '\0';
 164                        // get md5 sum of "<stamp>password" string
 165                        md5_begin(&md5.ctx);
 166                        md5_hash(&md5.ctx, buf, strlen(buf));
 167                        md5_hash(&md5.ctx, G.pass, strlen(G.pass));
 168                        md5_end(&md5.ctx, res);
 169                        *bin2hex(md5.hex, (char*)res, 16) = '\0';
 170                        // APOP
 171                        s = xasprintf("%s %s", G.user, md5.hex);
 172                        pop3_check("APOP %s", s);
 173                        free(s);
 174                        free(buf);
 175                // server ignores APOP -> use simple text authentication
 176                } else {
 177                        // USER
 178                        pop3_check("USER %s", G.user);
 179                        // PASS
 180                        pop3_check("PASS %s", G.pass);
 181                }
 182        }
 183
 184        // get mailbox statistics
 185        pop3_checkr("STAT", NULL, &buf);
 186
 187        // prepare message filename suffix
 188        hostname = safe_gethostname();
 189        pid = getpid();
 190
 191        // get messages counter
 192        // NOTE: we don't use xatou(buf) since buf is "nmsg nbytes"
 193        // we only need nmsg and atoi is just exactly what we need
 194        // if atoi fails to convert buf into number it returns 0
 195        // in this case the following loop simply will not be executed
 196        nmsg = atoi(buf);
 197        free(buf);
 198
 199        // loop through messages
 200        retr = (opts & OPT_T) ? xasprintf("TOP %%u %u", opt_nlines) : "RETR %u";
 201        for (; nmsg; nmsg--) {
 202
 203                char *filename;
 204                char *target;
 205                char *answer;
 206                FILE *fp;
 207#if ENABLE_FEATURE_POPMAILDIR_DELIVERY
 208                int rc;
 209#endif
 210                // generate unique filename
 211                filename  = xasprintf("tmp/%llu.%u.%s",
 212                        monotonic_us(), (unsigned)pid, hostname);
 213
 214                // retrieve message in ./tmp/ unless filter is specified
 215                pop3_check(retr, (const char *)(ptrdiff_t)nmsg);
 216
 217#if ENABLE_FEATURE_POPMAILDIR_DELIVERY
 218                // delivery helper ordered? -> setup pipe
 219                if (opts & (OPT_F|OPT_M)) {
 220                        // helper will have $FILENAME set to filename
 221                        xsetenv("FILENAME", filename);
 222                        fp = popen(delivery, "w");
 223                        unsetenv("FILENAME");
 224                        if (!fp) {
 225                                bb_perror_msg("delivery helper");
 226                                break;
 227                        }
 228                } else
 229#endif
 230                // create and open file filename
 231                fp = xfopen_for_write(filename);
 232
 233                // copy stdin to fp (either filename or delivery helper)
 234                while ((answer = xmalloc_fgets_str(stdin, "\r\n")) != NULL) {
 235                        char *s = answer;
 236                        if ('.' == answer[0]) {
 237                                if ('.' == answer[1])
 238                                        s++;
 239                                else if ('\r' == answer[1] && '\n' == answer[2] && '\0' == answer[3])
 240                                        break;
 241                        }
 242                        //*strchrnul(s, '\r') = '\n';
 243                        fputs(s, fp);
 244                        free(answer);
 245                }
 246
 247#if ENABLE_FEATURE_POPMAILDIR_DELIVERY
 248                // analyse delivery status
 249                if (opts & (OPT_F|OPT_M)) {
 250                        rc = pclose(fp);
 251                        if (99 == rc) // 99 means bail out
 252                                break;
 253//                      if (rc) // !0 means skip to the next message
 254                                goto skip;
 255//                      // 0 means continue
 256                } else {
 257                        // close filename
 258                        fclose(fp);
 259                }
 260#endif
 261
 262                // delete message from server
 263                if (!(opts & OPT_k))
 264                        pop3_check("DELE %u", (const char*)(ptrdiff_t)nmsg);
 265
 266                // atomically move message to ./new/
 267                target = xstrdup(filename);
 268                memcpy(target, "new", 3);
 269                // ... or just stop receiving on failure
 270                if (rename_or_warn(filename, target))
 271                        break;
 272                free(target);
 273
 274#if ENABLE_FEATURE_POPMAILDIR_DELIVERY
 275 skip:
 276#endif
 277                free(filename);
 278        }
 279
 280        // Bye
 281        pop3_check("QUIT", NULL);
 282
 283        if (ENABLE_FEATURE_CLEAN_UP) {
 284                free(G.user);
 285                free(G.pass);
 286        }
 287
 288        return EXIT_SUCCESS;
 289}
 290