spam.c

   1 /*@ S-nail - a mail user agent derived from Berkeley Mail.
   2  *@ Spam related facilities.
   3  *
   4  * Copyright (c) 2014 Steffen "Daode" Nurpmeso <sdaoden@users.sf.net>.
   5  *
   6  * Permission to use, copy, modify, and/or distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #ifndef HAVE_AMALGAMATION
  20 # include "nail.h"
  21 #endif
  22
  23 EMPTY_FILE(spam)
  24 #ifdef HAVE_SPAM
  25 /*
  26  * TODO - We cannot use the spamc library because of our jumping behaviour.
  27  * TODO   We could nonetheless if we'd start a fork(2)ed child which would
  28  * TODO   use the spamc library.
  29  * TODO -- In fact using a child process that is immune from the terrible
  30  * TODO    signal and jumping mess, and that controls further childs, and
  31  * TODO    gains file descriptors via sendmsg(2), and is started once it is
  32  * TODO    needed first, i have in mind for quite some time, for the transition
  33  * TODO    to a select(2) based implementation: we could slowly convert SMTP,
  34  * TODO    etc., finally IMAP, at which case we could rejoin back into a single
  35  * TODO    process program (unless we want to isolate the UI at that time, to
  36  * TODO    allow for some xUI protocol).
  37  * TODO    :: That is to say -- it's a horrible signal and jump mess ::
  38  * TODO - We do not yet handle direct communication with spamd(1).
  39  * TODO   I.e., this could be a lean alternative to the first item;
  40  * TODO   the protocol is easy and we could support ALL operations easily.
  41  * TODO - We do not yet update mails in place, i.e., replace the original
  42  * TODO   message with the updated one; we could easily do it as if `edit' has
  43  * TODO   been used, but the nail codebase doesn't truly support that for IMAP.
  44  * TODO   (And it seems a bit grazy to download a message, update it and upload
  45  * TODO   it again.)
  46  */
  47
  48 enum spam_action {
  49    _SPAM_RATE,
  50    _SPAM_HAM,
  51    _SPAM_SPAM,
  52    _SPAM_FORGET
  53 };
  54
  55 struct spam_vc {
  56    struct message *  mp;
  57    size_t            mno;
  58    int               action;
  59    int               __dummy;
  60    char *            comm_s;
  61    char *            buffer;
  62    /* TODO This codebase jumps around and uses "stacks" of signal handling;
  63     * TODO until some later time we have to play the same game */
  64    sighandler_type   otstp;
  65    sighandler_type   ottin;
  66    sighandler_type   ottou;
  67    sighandler_type   ohup;
  68    sighandler_type   opipe;
  69    sighandler_type   oint;
  70    char const *      comm_a[16];
  71 };
  72
  73 /* Indices according to enum spam_action */
  74 static char const _spam_comms[][16] = {
  75    "spamrate", "spamham", "spamspam", "spamforget"
  76 };
  77
  78 /* Shared action setup */
  79 static bool_t  _spam_action(enum spam_action sa, int *ip);
  80
  81 /* Convert a 2[.x]/whatever spam rate into message.m_spamscore */
  82 static void    _spam_rate2score(struct spam_vc *vc);
  83
  84 /* Interact with spamc(1) */
  85 static bool_t  _spam_interact(struct spam_vc *vc);
  86
  87 static bool_t
  88 _spam_action(enum spam_action sa, int *ip)
  89 {
  90    struct spam_vc vc;
  91    struct str str;
  92    size_t maxsize;
  93    char const *cp, **args;
  94    bool_t ok = FAL0;
  95
  96    vc.action = sa;
  97
  98    if ((cp = ok_vlook(spam_command)) == NULL) {
  99 #ifdef SPAMC_PATH
 100       cp = SPAMC_PATH;
 101 #else
 102       fprintf(stderr, tr(514, "`%s': *spam-command* is not set\n"),
 103          _spam_comms[sa]);
 104       goto jleave;
 105 #endif
 106    }
 107
 108    /* Prepare the spamc(1) command line */
 109    args = vc.comm_a;
 110    *args++ = cp;
 111
 112    switch (sa) {
 113    case _SPAM_RATE:
 114       *args = "-c";
 115       break;
 116    case _SPAM_HAM:
 117       args[1] = "ham";
 118       goto jlearn;
 119    case _SPAM_SPAM:
 120       args[1] = "spam";
 121       goto jlearn;
 122    case _SPAM_FORGET:
 123       args[1] = "forget";
 124 jlearn:
 125       *args = "-L";
 126       ++args;
 127       break;
 128    }
 129    ++args;
 130
 131    if ((cp = ok_vlook(spam_socket)) != NULL) {
 132       *args++ = "-U";
 133       *args++ = cp;
 134    } else {
 135       if ((cp = ok_vlook(spam_host)) != NULL) {
 136          *args++ = "-d";
 137          *args++ = cp;
 138       }
 139       if ((cp = ok_vlook(spam_port)) != NULL) {
 140          *args++ = "-p";
 141          *args++ = cp;
 142       }
 143    }
 144
 145    *args++ = "-l"; /* --log-to-stderr */
 146
 147    if ((cp = ok_vlook(spam_user)) != NULL) {
 148       *args++ = "-u";
 149       *args++ = cp;
 150    }
 151
 152    *args = NULL;
 153    vc.comm_s = str_concat_cpa(&str, vc.comm_a, " ")->s;
 154    if (options & OPT_DEBUG)
 155       fprintf(stderr, "spamc(1) via <%s>\n", vc.comm_s);
 156
 157    /* *spam-maxsize* we do handle ourselfs instead */
 158    maxsize = 0;
 159    if ((cp = ok_vlook(spam_maxsize)) != NULL)
 160       maxsize = (size_t)strtol(cp, NULL, 10);
 161    if (maxsize <= 0)
 162       maxsize = SPAM_MAXSIZE;
 163
 164    /* Finally get an I/O buffer */
 165    vc.buffer = salloc(BUFFER_SIZE);
 166
 167    for (ok = TRU1; *ip != 0; ++ip) {
 168       vc.mno = (size_t)*ip - 1;
 169       vc.mp = message + vc.mno;
 170       if (sa == _SPAM_RATE)
 171          vc.mp->m_spamscore = 0;
 172       if (vc.mp->m_size > maxsize) {
 173          if (options & OPT_VERBOSE)
 174             fprintf(stderr, tr(515,
 175                "`%s': message %lu exceeds maxsize (%lu > %lu), skip\n"),
 176                _spam_comms[sa], (ul_it)vc.mno + 1,
 177                (ul_it)vc.mp->m_size, (ul_it)maxsize);
 178          continue;
 179       }
 180       if ((ok = _spam_interact(&vc)) == FAL0)
 181          break;
 182    }
 183 #ifndef SPAMC_PATH
 184 jleave:
 185 #endif
 186    return ! ok;
 187 }
 188
 189 static void
 190 _spam_rate2score(struct spam_vc *vc)
 191 {
 192    char *cp;
 193    size_t size;
 194    ui_it m, s;
 195
 196    cp = strchr(vc->buffer, '/');
 197    if (cp == NULL)
 198       goto jleave;
 199    size = (size_t)(cp - vc->buffer);
 200    vc->buffer[size] = '\0';
 201
 202    m = (ui_it)strtol(vc->buffer, &cp, 10);
 203    if (cp == vc->buffer)
 204       goto jleave;
 205
 206    s = (*cp == '\0') ? 0 : (ui_it)strtol(++cp, NULL, 10);
 207
 208    vc->mp->m_spamscore = (m << 8) | (s & 0xFF);
 209 jleave:
 210    ;
 211 }
 212
 213 static sigjmp_buf __spam_actjmp; /* TODO someday, we won't need it no more */
 214 static int __spam_sig; /* TODO someday, we won't need it no more */
 215 static void
 216 __spam_onsig(int sig) /* TODO someday, we won't need it no more */
 217 {
 218    __spam_sig = sig;
 219    siglongjmp(__spam_actjmp, 1);
 220 }
 221
 222 static bool_t
 223 _spam_interact(struct spam_vc *vc)
 224 {
 225    int p2c[2], c2p[2];
 226    sigset_t cset;
 227    size_t size;
 228    pid_t pid;
 229    FILE *ibuf;
 230    enum {
 231       _NONE    = 0,
 232       _SIGHOLD = 1<<0,
 233       _P2C_0   = 1<<1,
 234       _P2C_1   = 1<<2,
 235       _P2C     = _P2C_0 | _P2C_1,
 236       _C2P_0   = 1<<3,
 237       _C2P_1   = 1<<4,
 238       _C2P     = _C2P_0 | _C2P_1,
 239       _JUMPED  = 1<<5,
 240       _RUNNING = 1<<6,
 241       _GOODRUN = 1<<7,
 242       _ERRORS  = 1<<8
 243    } state = _NONE;
 244
 245    setdot(vc->mp);
 246    if ((ibuf = setinput(&mb, vc->mp, NEED_BODY)) == NULL) {
 247       perror("setinput"); /* XXX tr() */
 248       goto j_leave;
 249    }
 250
 251    /* TODO Avoid that we jump away; yet necessary signal mess */
 252    vc->otstp = safe_signal(SIGTSTP, SIG_DFL);
 253    vc->ottin = safe_signal(SIGTTIN, SIG_DFL);
 254    vc->ottou = safe_signal(SIGTTOU, SIG_DFL);
 255    vc->opipe = safe_signal(SIGPIPE, SIG_IGN);
 256    hold_sigs();
 257    state |= _SIGHOLD;
 258    vc->ohup = safe_signal(SIGHUP, &__spam_onsig);
 259    vc->oint = safe_signal(SIGINT, &__spam_onsig);
 260    /* Keep sigs blocked */
 261    pid = 0; /* cc uninit */
 262
 263    if (! pipe_cloexec(p2c)) {
 264       perror("pipe"); /* XXX tr() */
 265       goto jleave;
 266    }
 267    state |= _P2C;
 268
 269    if (! pipe_cloexec(c2p)) {
 270       perror("pipe"); /* XXX tr() */
 271       goto jleave;
 272    }
 273    state |= _C2P;
 274
 275    if (sigsetjmp(__spam_actjmp, 1)) {
 276       state |= _JUMPED;
 277       goto jleave;
 278    }
 279    rele_sigs();
 280    state &= ~_SIGHOLD;
 281
 282    sigemptyset(&cset);
 283    pid = start_command(vc->comm_s, &cset, p2c[0], c2p[1], NULL, NULL, NULL);
 284    state |= _RUNNING;
 285    close(p2c[0]);
 286    state &= ~_P2C_0;
 287
 288    /* Yes, we could sendmp(SEND_MBOX), but simply passing through the MBOX
 289     * content does the same in effect, but is much more efficient.
 290     * NOTE: this may mean we pass a message without From_ line! */
 291    for (size = vc->mp->m_size; size > 0;) {
 292       size_t i = fread(vc->buffer, 1, MIN(size, BUFFER_SIZE), ibuf);
 293       if (i == 0) {
 294          if (ferror(ibuf))
 295             state |= _ERRORS;
 296          break;
 297       }
 298       size -= i;
 299       if (i != (size_t)write(p2c[1], vc->buffer, i)) {
 300          state |= _ERRORS;
 301          break;
 302       }
 303    }
 304
 305 jleave:
 306    /* In what follows you see a lot of races; these can't be helped without
 307     * atomic compare-and-swap; it only matters if we */
 308    if (state & _SIGHOLD) {
 309       state &= ~_SIGHOLD;
 310       rele_sigs();
 311    }
 312
 313    if (state & _P2C_0) {
 314       state &= ~_P2C_0;
 315       close(p2c[0]);
 316    }
 317    if (state & _C2P_1) {
 318       state &= ~_C2P_1;
 319       close(c2p[1]);
 320    }
 321    /* Close the write end, so that spamc(1) goes */
 322    if (state & _P2C_1) {
 323       state &= ~_P2C_1;
 324       close(p2c[1]);
 325    }
 326
 327    if (state & _RUNNING) {
 328       state &= ~_RUNNING;
 329       if (wait_child(pid, NULL))
 330          state |= _GOODRUN;
 331    }
 332
 333    /* XXX This only works because spamc(1) follows the clear protocol (1) read
 334     * XXX everything until EOF on input, then (2) work, then (3) output
 335     * XXX a single result line; otherwise we could deadlock here, but since
 336     * TODO this is rather intermediate, go with it */
 337    if (vc->action == _SPAM_RATE && ! (state & (_JUMPED | _ERRORS))) {
 338       ssize_t i = read(c2p[0], vc->buffer, BUFFER_SIZE - 1);
 339       if (i > 0) {
 340          vc->buffer[i] = '\0';
 341          _spam_rate2score(vc);
 342       } else if (i != 0)
 343          state |= _ERRORS;
 344    }
 345
 346    if (state & _C2P_0) {
 347       state &= ~_C2P_0;
 348       close(c2p[0]);
 349    }
 350
 351    if (vc->action == _SPAM_RATE) {
 352       switch (state & (_JUMPED | _GOODRUN | _ERRORS)) {
 353       case _GOODRUN:
 354          vc->mp->m_flag &= ~MSPAM;
 355          break;
 356       case 0:
 357          vc->mp->m_flag |= MSPAM;
 358       default:
 359          break;
 360       }
 361    } else {
 362       if (state & (_JUMPED | _ERRORS))
 363          /* xxx print message? */;
 364       else if (vc->action == _SPAM_SPAM)
 365          vc->mp->m_flag |= MSPAM;
 366       else if (vc->action == _SPAM_HAM)
 367          vc->mp->m_flag &= ~MSPAM;
 368    }
 369
 370    safe_signal(SIGINT, vc->oint);
 371    safe_signal(SIGHUP, vc->ohup);
 372    safe_signal(SIGPIPE, vc->opipe);
 373    safe_signal(SIGTSTP, vc->otstp);
 374    safe_signal(SIGTTIN, vc->ottin);
 375    safe_signal(SIGTTOU, vc->ottou);
 376
 377    /* Bounce jumps to the lex.c trampolines
 378     * (i'd have never believed i'd ever say or even do something like this) */
 379    if (state & _JUMPED) {
 380       sigemptyset(&cset);
 381       sigaddset(&cset, __spam_sig);
 382       sigprocmask(SIG_UNBLOCK, &cset, NULL);
 383       kill(0, __spam_sig);
 384    }
 385 j_leave:
 386    return ! (state & _ERRORS);
 387 }
 388
 389 FL int
 390 cspam_clear(void *v)
 391 {
 392    int *ip;
 393
 394    for (ip = v; *ip != 0; ++ip)
 395       message[(size_t)*ip - 1].m_flag &= ~MSPAM;
 396    return 0;
 397 }
 398
 399 FL int
 400 cspam_set(void *v)
 401 {
 402    int *ip;
 403
 404    for (ip = v; *ip != 0; ++ip)
 405       message[(size_t)*ip - 1].m_flag |= MSPAM;
 406    return 0;
 407 }
 408
 409 FL int
 410 cspam_forget(void *v)
 411 {
 412    return _spam_action(_SPAM_FORGET, (int*)v) ? OKAY : STOP;
 413 }
 414
 415 FL int
 416 cspam_ham(void *v)
 417 {
 418    return _spam_action(_SPAM_HAM, (int*)v) ? OKAY : STOP;
 419 }
 420
 421 FL int
 422 cspam_rate(void *v)
 423 {
 424    return _spam_action(_SPAM_RATE, (int*)v) ? OKAY : STOP;
 425 }
 426
 427 FL int
 428 cspam_spam(void *v)
 429 {
 430    return _spam_action(_SPAM_SPAM, (int*)v) ? OKAY : STOP;
 431 }
 432 #endif /* HAVE_SPAM */
 433
 434 /* vim:set fenc=utf-8:s-it-mode */