contrib/file-4/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 #include "magic.h"
  29 #include <stdarg.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32 #include <ctype.h>
  33
  34 #ifndef lint
  35 FILE_RCSID("@(#)$Id: funcs.c,v 1.14 2005/01/07 19:17:27 christos Exp $")
  36 #endif  /* lint */
  37 /*
  38  * Like printf, only we print to a buffer and advance it.
  39  */
  40 protected int
  41 file_printf(struct magic_set *ms, const char *fmt, ...)
  42 {
  43         va_list ap;
  44         size_t len;
  45         char *buf;
  46
  47         va_start(ap, fmt);
  48
  49         if ((len = vsnprintf(ms->o.ptr, ms->o.len, fmt, ap)) >= ms->o.len) {
  50                 va_end(ap);
  51                 if ((buf = realloc(ms->o.buf, len + 1024)) == NULL) {
  52                         file_oomem(ms);
  53                         return -1;
  54                 }
  55                 ms->o.ptr = buf + (ms->o.ptr - ms->o.buf);
  56                 ms->o.buf = buf;
  57                 ms->o.len = ms->o.size - (ms->o.ptr - ms->o.buf);
  58                 ms->o.size = len + 1024;
  59
  60                 va_start(ap, fmt);
  61                 len = vsnprintf(ms->o.ptr, ms->o.len, fmt, ap);
  62         }
  63         ms->o.ptr += len;
  64         ms->o.len -= len;
  65         va_end(ap);
  66         return 0;
  67 }
  68
  69 /*
  70  * error - print best error message possible
  71  */
  72 /*VARARGS*/
  73 protected void
  74 file_error(struct magic_set *ms, int error, const char *f, ...)
  75 {
  76         va_list va;
  77         /* Only the first error is ok */
  78         if (ms->haderr)
  79                 return;
  80         va_start(va, f);
  81         (void)vsnprintf(ms->o.buf, ms->o.size, f, va);
  82         va_end(va);
  83         if (error > 0) {
  84                 size_t len = strlen(ms->o.buf);
  85                 (void)snprintf(ms->o.buf + len, ms->o.size - len, " (%s)",
  86                     strerror(error));
  87         }
  88         ms->haderr++;
  89         ms->error = error;
  90 }
  91
  92
  93 protected void
  94 file_oomem(struct magic_set *ms)
  95 {
  96         file_error(ms, errno, "cannot allocate memory");
  97 }
  98
  99 protected void
 100 file_badseek(struct magic_set *ms)
 101 {
 102         file_error(ms, errno, "error seeking");
 103 }
 104
 105 protected void
 106 file_badread(struct magic_set *ms)
 107 {
 108         file_error(ms, errno, "error reading");
 109 }
 110
 111 #ifndef COMPILE_ONLY
 112 protected int
 113 file_buffer(struct magic_set *ms, int fd, const void *buf, size_t nb)
 114 {
 115     int m;
 116     /* try compression stuff */
 117     if ((m = file_zmagic(ms, fd, buf, nb)) == 0) {
 118         /* Check if we have a tar file */
 119         if ((m = file_is_tar(ms, buf, nb)) == 0) {
 120             /* try tests in /etc/magic (or surrogate magic file) */
 121             if ((m = file_softmagic(ms, buf, nb)) == 0) {
 122                 /* try known keywords, check whether it is ASCII */
 123                 if ((m = file_ascmagic(ms, buf, nb)) == 0) {
 124                     /* abandon hope, all ye who remain here */
 125                     if (file_printf(ms, ms->flags & MAGIC_MIME ?
 126                         "application/octet-stream" : "data") == -1)
 127                             return -1;
 128                     m = 1;
 129                 }
 130             }
 131         }
 132     }
 133     return m;
 134 }
 135 #endif
 136
 137 protected int
 138 file_reset(struct magic_set *ms)
 139 {
 140         if (ms->mlist == NULL) {
 141                 file_error(ms, 0, "no magic files loaded");
 142                 return -1;
 143         }
 144         ms->o.ptr = ms->o.buf;
 145         ms->haderr = 0;
 146         ms->error = -1;
 147         return 0;
 148 }
 149
 150 protected const char *
 151 file_getbuffer(struct magic_set *ms)
 152 {
 153         char *nbuf, *op, *np;
 154         size_t nsize;
 155
 156         if (ms->haderr)
 157                 return NULL;
 158
 159         if (ms->flags & MAGIC_RAW)
 160                 return ms->o.buf;
 161
 162         nsize = ms->o.len * 4 + 1;
 163         if (ms->o.psize < nsize) {
 164                 if ((nbuf = realloc(ms->o.pbuf, nsize)) == NULL) {
 165                         file_oomem(ms);
 166                         return NULL;
 167                 }
 168                 ms->o.psize = nsize;
 169                 ms->o.pbuf = nbuf;
 170         }
 171
 172         for (np = ms->o.pbuf, op = ms->o.buf; *op; op++) {
 173                 if (isprint((unsigned char)*op)) {
 174                         *np++ = *op;
 175                 } else {
 176                         *np++ = '\\';
 177                         *np++ = ((*op >> 6) & 3) + '0';
 178                         *np++ = ((*op >> 3) & 7) + '0';
 179                         *np++ = ((*op >> 0) & 7) + '0';
 180                 }
 181         }
 182         *np = '\0';
 183         return ms->o.pbuf;
 184 }