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-rw-r--r--src/plugins/jpeg_extractor.c353
1 files changed, 123 insertions, 230 deletions
diff --git a/src/plugins/jpeg_extractor.c b/src/plugins/jpeg_extractor.c
index a0722d4..2ef0677 100644
--- a/src/plugins/jpeg_extractor.c
+++ b/src/plugins/jpeg_extractor.c
@@ -1,10 +1,10 @@
1/* 1/*
2 This file is part of libextractor. 2 This file is part of libextractor.
3 (C) 2002, 2003, 2004 Vidyut Samanta and Christian Grothoff 3 (C) 2002, 2003, 2004, 2012 Vidyut Samanta and Christian Grothoff
4 4
5 libextractor is free software; you can redistribute it and/or modify 5 libextractor is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published 6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 2, or (at your 7 by the Free Software Foundation; either version 3, or (at your
8 option) any later version. 8 option) any later version.
9 9
10 libextractor is distributed in the hope that it will be useful, but 10 libextractor is distributed in the hope that it will be useful, but
@@ -17,261 +17,154 @@
17 Free Software Foundation, Inc., 59 Temple Place - Suite 330, 17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA. 18 Boston, MA 02111-1307, USA.
19 */ 19 */
20 20/**
21 * @file plugins/jpeg_extractor.c
22 * @brief plugin to support JPEG files
23 * @author Christian Grothoff
24 */
21#include "platform.h" 25#include "platform.h"
22#include "extractor.h" 26#include "extractor.h"
27#include <jpeglib.h>
28#include <setjmp.h>
23 29
24 30
25#define M_SOI 0xD8 /* Start Of Image (beginning of datastream) */
26#define M_EOI 0xD9 /* End Of Image (end of datastream) */
27#define M_SOS 0xDA /* Start Of Scan (begins compressed data) */
28#define M_APP12 0xEC
29#define M_COM 0xFE /* COMment */
30#define M_APP0 0xE0
31
32/** 31/**
33 * Get the next character in the sequence and advance 32 * Context for custom functions.
34 * the pointer *data to the next location in the sequence.
35 * If we're at the end, return -1.
36 */ 33 */
37#define NEXTC(data,end) ((*(data)<(end))?*((*(data))++):-1) 34struct Context
35{
36 /**
37 * Environment for longjmp from within error_exit handler.
38 */
39 jmp_buf env;
40};
38 41
39/* The macro does:
40unsigned int NEXTC(unsigned char ** data, char * end) {
41 if (*data < end) {
42 char result = **data;
43 (*data)++;
44 return result;
45 } else
46 return -1;
47}
48*/
49 42
50/** 43/**
51 * Read length, convert to unsigned int. 44 * Function used to avoid having libjpeg write error messages to the console.
52 * All 2-byte quantities in JPEG markers are MSB first
53 * @return -1 on error
54 */ 45 */
55static int 46static void
56readLength (const unsigned char **data, const unsigned char *end) 47no_emit (j_common_ptr cinfo, int msg_level)
57{ 48{
58 int c1; 49 /* do nothing */
59 int c2;
60
61 c1 = NEXTC (data, end);
62 if (c1 == -1)
63 return -1;
64 c2 = NEXTC (data, end);
65 if (c2 == -1)
66 return -1;
67 return ((((unsigned int) c1) << 8) + ((unsigned int) c2)) - 2;
68} 50}
69 51
52
70/** 53/**
71 * @return the next marker or -1 on error. 54 * Function used to avoid having libjpeg write error messages to the console.
72 */ 55 */
73static int 56static void
74next_marker (const unsigned char **data, const unsigned char *end) 57no_output (j_common_ptr cinfo)
75{ 58{
76 int c; 59 /* do nothing */
77 c = NEXTC (data, end);
78 while ((c != 0xFF) && (c != -1))
79 c = NEXTC (data, end);
80 do
81 {
82 c = NEXTC (data, end);
83 }
84 while (c == 0xFF);
85 return c;
86} 60}
87 61
62
63/**
64 * Function used to avoid having libjpeg kill our process.
65 */
88static void 66static void
89skip_variable (const unsigned char **data, const unsigned char *end) 67no_exit (j_common_ptr cinfo)
90{ 68{
91 int length; 69 struct Context *ctx = cinfo->client_data;
92 70
93 length = readLength (data, end); 71 /* we're not allowed to return (by API definition),
94 if (length < 0) 72 and we don't want to abort/exit. So we longjmp
95 { 73 to our cleanup code instead. */
96 (*data) = end; /* skip to the end */ 74 longjmp (ctx->env, 1);
97 return;
98 }
99 /* Skip over length bytes */
100 (*data) += length;
101} 75}
102 76
103static char *
104process_COM (const unsigned char **data, const unsigned char *end)
105{
106 unsigned int length;
107 int ch;
108 int pos;
109 char *comment;
110 77
111 length = readLength (data, end); 78/**
112 if (length <= 0) 79 * Main entry method for the 'image/jpeg' extraction plugin.
113 return NULL; 80 *
114 comment = malloc (length + 1); 81 * @param ec extraction context provided to the plugin
115 if (comment == NULL) 82 */
116 return NULL; 83void
117 pos = 0; 84EXTRACTOR_jpeg_extract_method (struct EXTRACTOR_ExtractContext *ec)
118 while (length > 0) 85{
86 struct jpeg_decompress_struct jds;
87 struct jpeg_error_mgr em;
88 void *buf;
89 ssize_t size;
90 int is_jpeg;
91 unsigned int rounds;
92 char format[128];
93 struct jpeg_marker_struct *mptr;
94 struct Context ctx;
95
96 is_jpeg = 0;
97 rounds = 0; /* used to avoid going on forever for non-jpeg files */
98 jpeg_std_error (&em);
99 em.emit_message = &no_emit;
100 em.output_message = &no_output;
101 em.error_exit = &no_exit;
102 jds.client_data = &ctx;
103 if (1 == setjmp (ctx.env))
104 goto EXIT; /* we get here if libjpeg calls 'no_exit' because it wants to die */
105 jds.err = &em;
106 jpeg_create_decompress (&jds);
107 jpeg_save_markers (&jds, JPEG_COM, 1024 * 8);
108 while ( (1 == is_jpeg) || (rounds++ < 8) )
119 { 109 {
120 ch = NEXTC (data, end); 110 if (-1 == (size = ec->read (ec->cls,
121 if ((ch == '\r') || (ch == '\n')) 111 &buf,
122 comment[pos++] = '\n'; 112 16 * 1024)))
123 else if (isprint ((unsigned char) ch)) 113 break;
124 comment[pos++] = ch; 114 if (0 == size)
125 length--; 115 break;
116 jpeg_mem_src (&jds, buf, size);
117 if (0 == is_jpeg)
118 {
119 if (JPEG_HEADER_OK == jpeg_read_header (&jds, 1))
120 is_jpeg = 1; /* ok, really a jpeg, keep going until the end */
121 continue;
122 }
123 jpeg_consume_input (&jds);
126 } 124 }
127 comment[pos] = '\0';
128 return comment;
129}
130
131 125
132int 126 if (1 != is_jpeg)
133EXTRACTOR_jpeg_extract (const unsigned char *data, 127 goto EXIT;
134 size_t size, 128 if (0 !=
135 EXTRACTOR_MetaDataProcessor proc, 129 ec->proc (ec->cls,
136 void *proc_cls, 130 "jpeg",
137 const char *options) 131 EXTRACTOR_METATYPE_MIMETYPE,
138{ 132 EXTRACTOR_METAFORMAT_UTF8,
139 int c1; 133 "text/plain",
140 int c2; 134 "image/jpeg",
141 int marker; 135 strlen ("image/jpeg") + 1))
142 const unsigned char *end; 136 goto EXIT;
143 char *tmp; 137 snprintf (format,
144 char val[128]; 138 sizeof (format),
145 139 "%ux%u",
146 if (size < 0x12) 140 (unsigned int) jds.image_width,
147 return 0; 141 (unsigned int) jds.image_height);
148 end = &data[size]; 142 if (0 !=
149 c1 = NEXTC (&data, end); 143 ec->proc (ec->cls,
150 c2 = NEXTC (&data, end); 144 "jpeg",
151 if ((c1 != 0xFF) || (c2 != M_SOI)) 145 EXTRACTOR_METATYPE_IMAGE_DIMENSIONS,
152 return 0; /* not a JPEG */ 146 EXTRACTOR_METAFORMAT_UTF8,
153 if (0 != proc (proc_cls, 147 "text/plain",
154 "jpeg", 148 format,
155 EXTRACTOR_METATYPE_MIMETYPE, 149 strlen (format) + 1))
156 EXTRACTOR_METAFORMAT_UTF8, 150 goto EXIT;
157 "text/plain", 151 for (mptr = jds.marker_list; NULL != mptr; mptr = mptr->next)
158 "image/jpeg",
159 strlen ("image/jpeg")+1))
160 return 1;
161 while (1)
162 { 152 {
163 marker = next_marker (&data, end); 153 if (JPEG_COM != mptr->marker)
164 switch (marker) 154 continue;
165 { 155 if (0 !=
166 case -1: /* end of file */ 156 ec->proc (ec->cls,
167 case M_SOS: 157 "jpeg",
168 case M_EOI: 158 EXTRACTOR_METATYPE_COMMENT,
169 goto RETURN; 159 EXTRACTOR_METAFORMAT_C_STRING,
170 case M_APP0: 160 "text/plain",
171 { 161 (const char *) mptr->data,
172 int len = readLength (&data, end); 162 mptr->data_length))
173 if (len < 0x8) 163 goto EXIT;
174 goto RETURN;
175 if (0 == strncmp ((char *) data, "JFIF", 4))
176 {
177 switch (data[0x4])
178 {
179 case 1: /* dots per inch */
180 snprintf (val,
181 sizeof (val),
182 _("%ux%u dots per inch"),
183 (data[0x8] << 8) + data[0x9],
184 (data[0xA] << 8) + data[0xB]);
185 if (0 != proc (proc_cls,
186 "jpeg",
187 EXTRACTOR_METATYPE_IMAGE_RESOLUTION,
188 EXTRACTOR_METAFORMAT_UTF8,
189 "text/plain",
190 val,
191 strlen (val)+1))
192 return 1;
193 break;
194 case 2: /* dots per cm */
195 snprintf (val,
196 sizeof (val),
197 _("%ux%u dots per cm"),
198 (data[0x8] << 8) + data[0x9],
199 (data[0xA] << 8) + data[0xB]);
200 if (0 != proc (proc_cls,
201 "jpeg",
202 EXTRACTOR_METATYPE_IMAGE_RESOLUTION,
203 EXTRACTOR_METAFORMAT_UTF8,
204 "text/plain",
205 val,
206 strlen (val)+1))
207 return 1;
208 break;
209 case 0: /* no unit given */
210 snprintf (val,
211 sizeof (val),
212 _("%ux%u dots per inch?"),
213 (data[0x8] << 8) + data[0x9],
214 (data[0xA] << 8) + data[0xB]);
215 if (0 != proc (proc_cls,
216 "jpeg",
217 EXTRACTOR_METATYPE_IMAGE_RESOLUTION,
218 EXTRACTOR_METAFORMAT_UTF8,
219 "text/plain",
220 val,
221 strlen (val)+1))
222 return 1;
223 break;
224 default: /* unknown unit */
225 break;
226 }
227 }
228 data = &data[len];
229 break;
230 }
231 case 0xC0:
232 {
233 int len = readLength (&data, end);
234 if (len < 0x9)
235 goto RETURN;
236 snprintf (val,
237 sizeof (val),
238 "%ux%u",
239 (data[0x3] << 8) + data[0x4],
240 (data[0x1] << 8) + data[0x2]);
241 if (0 != proc (proc_cls,
242 "jpeg",
243 EXTRACTOR_METATYPE_IMAGE_DIMENSIONS,
244 EXTRACTOR_METAFORMAT_UTF8,
245 "text/plain",
246 val,
247 strlen (val)+1))
248 return 1;
249 data = &data[len];
250 break;
251 }
252 case M_COM:
253 case M_APP12:
254 tmp = process_COM (&data, end);
255 if (NULL == tmp)
256 break;
257 if (0 != proc (proc_cls,
258 "jpeg",
259 EXTRACTOR_METATYPE_COMMENT,
260 EXTRACTOR_METAFORMAT_UTF8,
261 "text/plain",
262 tmp,
263 strlen (tmp)+1))
264 {
265 free (tmp);
266 return 1;
267 }
268 free (tmp);
269 break;
270 default:
271 skip_variable (&data, end);
272 break;
273 }
274 } 164 }
275RETURN: 165
276 return 0; 166 EXIT:
167 jpeg_destroy_decompress (&jds);
277} 168}
169
170/* end of jpeg_extractor.c */
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