contrib/file/src/funcs.c

   1 /*
   2  * Copyright (c) Christos Zoulas 2003.
   3  * All Rights Reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice immediately at the beginning of the file, without modification,
  10  *    this list of conditions, and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
  19  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  */
  27 #include "file.h"
  28
  29 #ifndef lint
  30 FILE_RCSID("@(#)$File: funcs.c,v 1.93 2017/08/28 13:39:18 christos Exp $")
  31 #endif  /* lint */
  32
  33 #include "magic.h"
  34 #include <assert.h>
  35 #include <stdarg.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38 #include <ctype.h>
  39 #if defined(HAVE_WCHAR_H)
  40 #include <wchar.h>
  41 #endif
  42 #if defined(HAVE_WCTYPE_H)
  43 #include <wctype.h>
  44 #endif
  45 #if defined(HAVE_LIMITS_H)
  46 #include <limits.h>
  47 #endif
  48
  49 #ifndef SIZE_MAX
  50 #define SIZE_MAX        ((size_t)~0)
  51 #endif
  52
  53 /*
  54  * Like printf, only we append to a buffer.
  55  */
  56 protected int
  57 file_vprintf(struct magic_set *ms, const char *fmt, va_list ap)
  58 {
  59         int len;
  60         char *buf, *newstr;
  61
  62         if (ms->event_flags & EVENT_HAD_ERR)
  63                 return 0;
  64         len = vasprintf(&buf, fmt, ap);
  65         if (len < 0)
  66                 goto out;
  67
  68         if (ms->o.buf != NULL) {
  69                 len = asprintf(&newstr, "%s%s", ms->o.buf, buf);
  70                 free(buf);
  71                 if (len < 0)
  72                         goto out;
  73                 free(ms->o.buf);
  74                 buf = newstr;
  75         }
  76         ms->o.buf = buf;
  77         return 0;
  78 out:
  79         fprintf(stderr, "vasprintf failed (%s)", strerror(errno));
  80         return -1;
  81 }
  82
  83 protected int
  84 file_printf(struct magic_set *ms, const char *fmt, ...)
  85 {
  86         int rv;
  87         va_list ap;
  88
  89         va_start(ap, fmt);
  90         rv = file_vprintf(ms, fmt, ap);
  91         va_end(ap);
  92         return rv;
  93 }
  94
  95 /*
  96  * error - print best error message possible
  97  */
  98 /*VARARGS*/
  99 __attribute__((__format__(__printf__, 3, 0)))
 100 private void
 101 file_error_core(struct magic_set *ms, int error, const char *f, va_list va,
 102     size_t lineno)
 103 {
 104         /* Only the first error is ok */
 105         if (ms->event_flags & EVENT_HAD_ERR)
 106                 return;
 107         if (lineno != 0) {
 108                 free(ms->o.buf);
 109                 ms->o.buf = NULL;
 110                 file_printf(ms, "line %" SIZE_T_FORMAT "u:", lineno);
 111         }
 112         if (ms->o.buf && *ms->o.buf)
 113                 file_printf(ms, " ");
 114         file_vprintf(ms, f, va);
 115         if (error > 0)
 116                 file_printf(ms, " (%s)", strerror(error));
 117         ms->event_flags |= EVENT_HAD_ERR;
 118         ms->error = error;
 119 }
 120
 121 /*VARARGS*/
 122 protected void
 123 file_error(struct magic_set *ms, int error, const char *f, ...)
 124 {
 125         va_list va;
 126         va_start(va, f);
 127         file_error_core(ms, error, f, va, 0);
 128         va_end(va);
 129 }
 130
 131 /*
 132  * Print an error with magic line number.
 133  */
 134 /*VARARGS*/
 135 protected void
 136 file_magerror(struct magic_set *ms, const char *f, ...)
 137 {
 138         va_list va;
 139         va_start(va, f);
 140         file_error_core(ms, 0, f, va, ms->line);
 141         va_end(va);
 142 }
 143
 144 protected void
 145 file_oomem(struct magic_set *ms, size_t len)
 146 {
 147         file_error(ms, errno, "cannot allocate %" SIZE_T_FORMAT "u bytes",
 148             len);
 149 }
 150
 151 protected void
 152 file_badseek(struct magic_set *ms)
 153 {
 154         file_error(ms, errno, "error seeking");
 155 }
 156
 157 protected void
 158 file_badread(struct magic_set *ms)
 159 {
 160         file_error(ms, errno, "error reading");
 161 }
 162
 163 #ifndef COMPILE_ONLY
 164
 165 static int
 166 checkdone(struct magic_set *ms, int *rv)
 167 {
 168         if ((ms->flags & MAGIC_CONTINUE) == 0)
 169                 return 1;
 170         if (file_printf(ms, "\n- ") == -1)
 171                 *rv = -1;
 172         return 0;
 173 }
 174
 175 /*ARGSUSED*/
 176 protected int
 177 file_buffer(struct magic_set *ms, int fd, const char *inname __attribute__ ((__unused__)),
 178     const void *buf, size_t nb)
 179 {
 180         int m = 0, rv = 0, looks_text = 0;
 181         const unsigned char *ubuf = CAST(const unsigned char *, buf);
 182         unichar *u8buf = NULL;
 183         size_t ulen;
 184         const char *code = NULL;
 185         const char *code_mime = "binary";
 186         const char *type = "application/octet-stream";
 187         const char *def = "data";
 188         const char *ftype = NULL;
 189
 190         if (nb == 0) {
 191                 def = "empty";
 192                 type = "application/x-empty";
 193                 goto simple;
 194         } else if (nb == 1) {
 195                 def = "very short file (no magic)";
 196                 goto simple;
 197         }
 198
 199         if ((ms->flags & MAGIC_NO_CHECK_ENCODING) == 0) {
 200                 looks_text = file_encoding(ms, ubuf, nb, &u8buf, &ulen,
 201                     &code, &code_mime, &ftype);
 202         }
 203
 204 #ifdef __EMX__
 205         if ((ms->flags & MAGIC_NO_CHECK_APPTYPE) == 0 && inname) {
 206                 m = file_os2_apptype(ms, inname, buf, nb);
 207                 if ((ms->flags & MAGIC_DEBUG) != 0)
 208                         (void)fprintf(stderr, "[try os2_apptype %d]\n", m);
 209                 switch (m) {
 210                 case -1:
 211                         return -1;
 212                 case 0:
 213                         break;
 214                 default:
 215                         return 1;
 216                 }
 217         }
 218 #endif
 219 #if HAVE_FORK
 220         /* try compression stuff */
 221         if ((ms->flags & MAGIC_NO_CHECK_COMPRESS) == 0) {
 222                 m = file_zmagic(ms, fd, inname, ubuf, nb);
 223                 if ((ms->flags & MAGIC_DEBUG) != 0)
 224                         (void)fprintf(stderr, "[try zmagic %d]\n", m);
 225                 if (m) {
 226                         goto done_encoding;
 227                 }
 228         }
 229 #endif
 230         /* Check if we have a tar file */
 231         if ((ms->flags & MAGIC_NO_CHECK_TAR) == 0) {
 232                 m = file_is_tar(ms, ubuf, nb);
 233                 if ((ms->flags & MAGIC_DEBUG) != 0)
 234                         (void)fprintf(stderr, "[try tar %d]\n", m);
 235                 if (m) {
 236                         if (checkdone(ms, &rv))
 237                                 goto done;
 238                 }
 239         }
 240
 241         /* Check if we have a CDF file */
 242         if ((ms->flags & MAGIC_NO_CHECK_CDF) == 0) {
 243                 m = file_trycdf(ms, fd, ubuf, nb);
 244                 if ((ms->flags & MAGIC_DEBUG) != 0)
 245                         (void)fprintf(stderr, "[try cdf %d]\n", m);
 246                 if (m) {
 247                         if (checkdone(ms, &rv))
 248                                 goto done;
 249                 }
 250         }
 251
 252         /* try soft magic tests */
 253         if ((ms->flags & MAGIC_NO_CHECK_SOFT) == 0) {
 254                 m = file_softmagic(ms, ubuf, nb, NULL, NULL, BINTEST,
 255                     looks_text);
 256                 if ((ms->flags & MAGIC_DEBUG) != 0)
 257                         (void)fprintf(stderr, "[try softmagic %d]\n", m);
 258                 if (m) {
 259 #ifdef BUILTIN_ELF
 260                         if ((ms->flags & MAGIC_NO_CHECK_ELF) == 0 && m == 1 &&
 261                             nb > 5 && fd != -1) {
 262                                 /*
 263                                  * We matched something in the file, so this
 264                                  * *might* be an ELF file, and the file is at
 265                                  * least 5 bytes long, so if it's an ELF file
 266                                  * it has at least one byte past the ELF magic
 267                                  * number - try extracting information from the
 268                                  * ELF headers that cannot easily * be
 269                                  * extracted with rules in the magic file.
 270                                  */
 271                                 m = file_tryelf(ms, fd, ubuf, nb);
 272                                 if ((ms->flags & MAGIC_DEBUG) != 0)
 273                                         (void)fprintf(stderr, "[try elf %d]\n",
 274                                             m);
 275                         }
 276 #endif
 277                         if (checkdone(ms, &rv))
 278                                 goto done;
 279                 }
 280         }
 281
 282         /* try text properties */
 283         if ((ms->flags & MAGIC_NO_CHECK_TEXT) == 0) {
 284
 285                 m = file_ascmagic(ms, ubuf, nb, looks_text);
 286                 if ((ms->flags & MAGIC_DEBUG) != 0)
 287                         (void)fprintf(stderr, "[try ascmagic %d]\n", m);
 288                 if (m) {
 289                         if (checkdone(ms, &rv))
 290                                 goto done;
 291                 }
 292         }
 293
 294 simple:
 295         /* give up */
 296         m = 1;
 297         if (ms->flags & MAGIC_MIME) {
 298                 if ((ms->flags & MAGIC_MIME_TYPE) &&
 299                     file_printf(ms, "%s", type) == -1)
 300                         rv = -1;
 301         } else if (ms->flags & MAGIC_APPLE) {
 302                 if (file_printf(ms, "UNKNUNKN") == -1)
 303                         rv = -1;
 304         } else if (ms->flags & MAGIC_EXTENSION) {
 305                 if (file_printf(ms, "???") == -1)
 306                         rv = -1;
 307         } else {
 308                 if (file_printf(ms, "%s", def) == -1)
 309                         rv = -1;
 310         }
 311  done:
 312         if ((ms->flags & MAGIC_MIME_ENCODING) != 0) {
 313                 if (ms->flags & MAGIC_MIME_TYPE)
 314                         if (file_printf(ms, "; charset=") == -1)
 315                                 rv = -1;
 316                 if (file_printf(ms, "%s", code_mime) == -1)
 317                         rv = -1;
 318         }
 319 #if HAVE_FORK
 320  done_encoding:
 321 #endif
 322         free(u8buf);
 323         if (rv)
 324                 return rv;
 325
 326         return m;
 327 }
 328 #endif
 329
 330 protected int
 331 file_reset(struct magic_set *ms, int checkloaded)
 332 {
 333         if (checkloaded && ms->mlist[0] == NULL) {
 334                 file_error(ms, 0, "no magic files loaded");
 335                 return -1;
 336         }
 337         if (ms->o.buf) {
 338                 free(ms->o.buf);
 339                 ms->o.buf = NULL;
 340         }
 341         if (ms->o.pbuf) {
 342                 free(ms->o.pbuf);
 343                 ms->o.pbuf = NULL;
 344         }
 345         ms->event_flags &= ~EVENT_HAD_ERR;
 346         ms->error = -1;
 347         return 0;
 348 }
 349
 350 #define OCTALIFY(n, o)  \
 351         /*LINTED*/ \
 352         (void)(*(n)++ = '\\', \
 353         *(n)++ = (((uint32_t)*(o) >> 6) & 3) + '0', \
 354         *(n)++ = (((uint32_t)*(o) >> 3) & 7) + '0', \
 355         *(n)++ = (((uint32_t)*(o) >> 0) & 7) + '0', \
 356         (o)++)
 357
 358 protected const char *
 359 file_getbuffer(struct magic_set *ms)
 360 {
 361         char *pbuf, *op, *np;
 362         size_t psize, len;
 363
 364         if (ms->event_flags & EVENT_HAD_ERR)
 365                 return NULL;
 366
 367         if (ms->flags & MAGIC_RAW)
 368                 return ms->o.buf;
 369
 370         if (ms->o.buf == NULL)
 371                 return NULL;
 372
 373         /* * 4 is for octal representation, + 1 is for NUL */
 374         len = strlen(ms->o.buf);
 375         if (len > (SIZE_MAX - 1) / 4) {
 376                 file_oomem(ms, len);
 377                 return NULL;
 378         }
 379         psize = len * 4 + 1;
 380         if ((pbuf = CAST(char *, realloc(ms->o.pbuf, psize))) == NULL) {
 381                 file_oomem(ms, psize);
 382                 return NULL;
 383         }
 384         ms->o.pbuf = pbuf;
 385
 386 #if defined(HAVE_WCHAR_H) && defined(HAVE_MBRTOWC) && defined(HAVE_WCWIDTH)
 387         {
 388                 mbstate_t state;
 389                 wchar_t nextchar;
 390                 int mb_conv = 1;
 391                 size_t bytesconsumed;
 392                 char *eop;
 393                 (void)memset(&state, 0, sizeof(mbstate_t));
 394
 395                 np = ms->o.pbuf;
 396                 op = ms->o.buf;
 397                 eop = op + len;
 398
 399                 while (op < eop) {
 400                         bytesconsumed = mbrtowc(&nextchar, op,
 401                             (size_t)(eop - op), &state);
 402                         if (bytesconsumed == (size_t)(-1) ||
 403                             bytesconsumed == (size_t)(-2)) {
 404                                 mb_conv = 0;
 405                                 break;
 406                         }
 407
 408                         if (iswprint(nextchar)) {
 409                                 (void)memcpy(np, op, bytesconsumed);
 410                                 op += bytesconsumed;
 411                                 np += bytesconsumed;
 412                         } else {
 413                                 while (bytesconsumed-- > 0)
 414                                         OCTALIFY(np, op);
 415                         }
 416                 }
 417                 *np = '\0';
 418
 419                 /* Parsing succeeded as a multi-byte sequence */
 420                 if (mb_conv != 0)
 421                         return ms->o.pbuf;
 422         }
 423 #endif
 424
 425         for (np = ms->o.pbuf, op = ms->o.buf; *op;) {
 426                 if (isprint((unsigned char)*op)) {
 427                         *np++ = *op++;
 428                 } else {
 429                         OCTALIFY(np, op);
 430                 }
 431         }
 432         *np = '\0';
 433         return ms->o.pbuf;
 434 }
 435
 436 protected int
 437 file_check_mem(struct magic_set *ms, unsigned int level)
 438 {
 439         size_t len;
 440
 441         if (level >= ms->c.len) {
 442                 len = (ms->c.len = 20 + level) * sizeof(*ms->c.li);
 443                 ms->c.li = CAST(struct level_info *, (ms->c.li == NULL) ?
 444                     malloc(len) :
 445                     realloc(ms->c.li, len));
 446                 if (ms->c.li == NULL) {
 447                         file_oomem(ms, len);
 448                         return -1;
 449                 }
 450         }
 451         ms->c.li[level].got_match = 0;
 452 #ifdef ENABLE_CONDITIONALS
 453         ms->c.li[level].last_match = 0;
 454         ms->c.li[level].last_cond = COND_NONE;
 455 #endif /* ENABLE_CONDITIONALS */
 456         return 0;
 457 }
 458
 459 protected size_t
 460 file_printedlen(const struct magic_set *ms)
 461 {
 462         return ms->o.buf == NULL ? 0 : strlen(ms->o.buf);
 463 }
 464
 465 protected int
 466 file_replace(struct magic_set *ms, const char *pat, const char *rep)
 467 {
 468         file_regex_t rx;
 469         int rc, rv = -1;
 470
 471         rc = file_regcomp(&rx, pat, REG_EXTENDED);
 472         if (rc) {
 473                 file_regerror(&rx, rc, ms);
 474         } else {
 475                 regmatch_t rm;
 476                 int nm = 0;
 477                 while (file_regexec(&rx, ms->o.buf, 1, &rm, 0) == 0) {
 478                         ms->o.buf[rm.rm_so] = '\0';
 479                         if (file_printf(ms, "%s%s", rep,
 480                             rm.rm_eo != 0 ? ms->o.buf + rm.rm_eo : "") == -1)
 481                                 goto out;
 482                         nm++;
 483                 }
 484                 rv = nm;
 485         }
 486 out:
 487         file_regfree(&rx);
 488         return rv;
 489 }
 490
 491 protected int
 492 file_regcomp(file_regex_t *rx, const char *pat, int flags)
 493 {
 494 #ifdef USE_C_LOCALE
 495         rx->c_lc_ctype = newlocale(LC_CTYPE_MASK, "C", 0);
 496         assert(rx->c_lc_ctype != NULL);
 497         rx->old_lc_ctype = uselocale(rx->c_lc_ctype);
 498         assert(rx->old_lc_ctype != NULL);
 499 #else
 500         rx->old_lc_ctype = setlocale(LC_CTYPE, "C");
 501 #endif
 502         rx->pat = pat;
 503
 504         return rx->rc = regcomp(&rx->rx, pat, flags);
 505 }
 506
 507 protected int
 508 file_regexec(file_regex_t *rx, const char *str, size_t nmatch,
 509     regmatch_t* pmatch, int eflags)
 510 {
 511         assert(rx->rc == 0);
 512         /* XXX: force initialization because glibc does not always do this */
 513         memset(pmatch, 0, nmatch * sizeof(*pmatch));
 514         return regexec(&rx->rx, str, nmatch, pmatch, eflags);
 515 }
 516
 517 protected void
 518 file_regfree(file_regex_t *rx)
 519 {
 520         if (rx->rc == 0)
 521                 regfree(&rx->rx);
 522 #ifdef USE_C_LOCALE
 523         (void)uselocale(rx->old_lc_ctype);
 524         freelocale(rx->c_lc_ctype);
 525 #else
 526         (void)setlocale(LC_CTYPE, rx->old_lc_ctype);
 527 #endif
 528 }
 529
 530 protected void
 531 file_regerror(file_regex_t *rx, int rc, struct magic_set *ms)
 532 {
 533         char errmsg[512];
 534
 535         (void)regerror(rc, &rx->rx, errmsg, sizeof(errmsg));
 536         file_magerror(ms, "regex error %d for `%s', (%s)", rc, rx->pat,
 537             errmsg);
 538 }
 539
 540 protected file_pushbuf_t *
 541 file_push_buffer(struct magic_set *ms)
 542 {
 543         file_pushbuf_t *pb;
 544
 545         if (ms->event_flags & EVENT_HAD_ERR)
 546                 return NULL;
 547
 548         if ((pb = (CAST(file_pushbuf_t *, malloc(sizeof(*pb))))) == NULL)
 549                 return NULL;
 550
 551         pb->buf = ms->o.buf;
 552         pb->offset = ms->offset;
 553
 554         ms->o.buf = NULL;
 555         ms->offset = 0;
 556
 557         return pb;
 558 }
 559
 560 protected char *
 561 file_pop_buffer(struct magic_set *ms, file_pushbuf_t *pb)
 562 {
 563         char *rbuf;
 564
 565         if (ms->event_flags & EVENT_HAD_ERR) {
 566                 free(pb->buf);
 567                 free(pb);
 568                 return NULL;
 569         }
 570
 571         rbuf = ms->o.buf;
 572
 573         ms->o.buf = pb->buf;
 574         ms->offset = pb->offset;
 575
 576         free(pb);
 577         return rbuf;
 578 }
 579
 580 /*
 581  * convert string to ascii printable format.
 582  */
 583 protected char *
 584 file_printable(char *buf, size_t bufsiz, const char *str)
 585 {
 586         char *ptr, *eptr;
 587         const unsigned char *s = (const unsigned char *)str;
 588
 589         for (ptr = buf, eptr = ptr + bufsiz - 1; ptr < eptr && *s; s++) {
 590                 if (isprint(*s)) {
 591                         *ptr++ = *s;
 592                         continue;
 593                 }
 594                 if (ptr >= eptr - 3)
 595                         break;
 596                 *ptr++ = '\\';
 597                 *ptr++ = ((CAST(unsigned int, *s) >> 6) & 7) + '0';
 598                 *ptr++ = ((CAST(unsigned int, *s) >> 3) & 7) + '0';
 599                 *ptr++ = ((CAST(unsigned int, *s) >> 0) & 7) + '0';
 600         }
 601         *ptr = '\0';
 602         return buf;
 603 }