1 /* $OpenBSD: funcs.c,v 1.4 2007/07/09 16:39:48 dim Exp $ */
2 /*
3 * Copyright (c) Christos Zoulas 2003.
4 * All Rights Reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice immediately at the beginning of the file, without modification,
11 * this list of conditions, and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote products
16 * derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
22 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30 #include "file.h"
31 #include "magic.h"
32 #include <limits.h>
33 #include <stdarg.h>
34 #include <stddef.h>
35 #include <stdlib.h>
36 #include <string.h>
37 #include <ctype.h>
38
39 __RCSID("$MirOS: src/usr.bin/file/funcs.c,v 1.2 2007/07/10 14:22:36 tg Exp $");
40
41 /*
42 * Like printf, only we print to a buffer and advance it.
43 */
44 protected int
file_printf(struct magic_set * ms,const char * fmt,...)45 file_printf(struct magic_set *ms, const char *fmt, ...)
46 {
47 va_list ap;
48 int len;
49 size_t size;
50 char *buf;
51 ptrdiff_t diff;
52
53 va_start(ap, fmt);
54
55 len = vsnprintf(ms->o.ptr, ms->o.left, fmt, ap);
56 if (len == -1) {
57 file_error(ms, errno, "vsnprintf failed");
58 return -1;
59 } else if ((size_t)len >= ms->o.left) {
60 va_end(ap);
61 size = (ms->o.size - ms->o.left) + len + 1024;
62 if ((buf = realloc(ms->o.buf, size)) == NULL) {
63 file_oomem(ms);
64 return -1;
65 }
66 diff = ms->o.ptr - ms->o.buf;
67 ms->o.ptr = buf + diff;
68 ms->o.buf = buf;
69 ms->o.left = size - diff;
70 ms->o.size = size;
71
72 va_start(ap, fmt);
73 len = vsnprintf(ms->o.ptr, ms->o.left, fmt, ap);
74 if (len == -1) {
75 file_error(ms, errno, "vsnprintf failed");
76 return -1;
77 }
78 }
79 ms->o.ptr += len;
80 ms->o.left -= len;
81 va_end(ap);
82 return 0;
83 }
84
85 /*
86 * error - print best error message possible
87 */
88 /*VARARGS*/
89 protected void
file_error(struct magic_set * ms,int error,const char * f,...)90 file_error(struct magic_set *ms, int error, const char *f, ...)
91 {
92 va_list va;
93 /* Only the first error is ok */
94 if (ms->haderr)
95 return;
96 va_start(va, f);
97 (void)vsnprintf(ms->o.buf, ms->o.size, f, va);
98 va_end(va);
99 if (error > 0) {
100 size_t len = strlen(ms->o.buf);
101 (void)snprintf(ms->o.buf + len, ms->o.size - len, " (%s)",
102 strerror(error));
103 }
104 ms->haderr++;
105 ms->error = error;
106 }
107
108
109 protected void
file_oomem(struct magic_set * ms)110 file_oomem(struct magic_set *ms)
111 {
112 file_error(ms, errno, "cannot allocate memory");
113 }
114
115 protected void
file_badseek(struct magic_set * ms)116 file_badseek(struct magic_set *ms)
117 {
118 file_error(ms, errno, "error seeking");
119 }
120
121 protected void
file_badread(struct magic_set * ms)122 file_badread(struct magic_set *ms)
123 {
124 file_error(ms, errno, "error reading");
125 }
126
127 protected int
file_buffer(struct magic_set * ms,const void * buf,size_t nb)128 file_buffer(struct magic_set *ms, const void *buf, size_t nb)
129 {
130 int m;
131 /* try compression stuff */
132 if ((m = file_zmagic(ms, buf, nb)) == 0) {
133 /* Check if we have a tar file */
134 if ((m = file_is_tar(ms, buf, nb)) == 0) {
135 /* try tests in /etc/magic (or surrogate magic file) */
136 if ((m = file_softmagic(ms, buf, nb)) == 0) {
137 /* try known keywords, check whether it is ASCII */
138 if ((m = file_ascmagic(ms, buf, nb)) == 0) {
139 /* abandon hope, all ye who remain here */
140 if (file_printf(ms, ms->flags & MAGIC_MIME ?
141 "application/octet-stream" : "data") == -1)
142 return -1;
143 m = 1;
144 }
145 }
146 }
147 }
148 return m;
149 }
150
151 protected int
file_reset(struct magic_set * ms)152 file_reset(struct magic_set *ms)
153 {
154 if (ms->mlist == NULL) {
155 file_error(ms, 0, "no magic files loaded");
156 return -1;
157 }
158 ms->o.ptr = ms->o.buf;
159 ms->haderr = 0;
160 ms->error = -1;
161 return 0;
162 }
163
164 protected const char *
file_getbuffer(struct magic_set * ms)165 file_getbuffer(struct magic_set *ms)
166 {
167 char *pbuf, *op, *np;
168 size_t psize, len;
169
170 if (ms->haderr)
171 return NULL;
172
173 if (ms->flags & MAGIC_RAW)
174 return ms->o.buf;
175
176 len = ms->o.size - ms->o.left;
177 if (len > (SIZE_T_MAX - 1) / 4) {
178 file_oomem(ms);
179 return NULL;
180 }
181 /* * 4 is for octal representation, + 1 is for NUL */
182 psize = len * 4 + 1;
183 if (ms->o.psize < psize) {
184 if ((pbuf = realloc(ms->o.pbuf, psize)) == NULL) {
185 file_oomem(ms);
186 return NULL;
187 }
188 ms->o.psize = psize;
189 ms->o.pbuf = pbuf;
190 }
191
192 for (np = ms->o.pbuf, op = ms->o.buf; *op; op++) {
193 if (isprint((unsigned char)*op)) {
194 *np++ = *op;
195 } else {
196 *np++ = '\\';
197 *np++ = ((*op >> 6) & 3) + '0';
198 *np++ = ((*op >> 3) & 7) + '0';
199 *np++ = ((*op >> 0) & 7) + '0';
200 }
201 }
202 *np = '\0';
203 return ms->o.pbuf;
204 }
205