1 /* flac - Command-line FLAC encoder/decoder
2 * Copyright (C) 2002-2009 Josh Coalson
3 * Copyright (C) 2011-2016 Xiph.Org Foundation
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; either version 2
8 * of the License, or (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
18 */
19
20 #ifdef HAVE_CONFIG_H
21 # include <config.h>
22 #endif
23
24 #include "vorbiscomment.h"
25 #include "FLAC/assert.h"
26 #include "FLAC/metadata.h"
27 #include "share/grabbag.h" /* for grabbag__file_get_filesize() */
28 #include "share/utf8.h"
29 #include <ctype.h>
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include "share/compat.h"
34
35
36 /*
37 * This struct and the following 4 static functions are copied from
38 * ../metaflac/. Maybe someday there will be a convenience
39 * library for Vorbis comment parsing.
40 */
41 typedef struct {
42 char *field; /* the whole field as passed on the command line, i.e. "NAME=VALUE" */
43 char *field_name;
44 /* according to the vorbis spec, field values can contain \0 so simple C strings are not enough here */
45 unsigned field_value_length;
46 char *field_value;
47 FLAC__bool field_value_from_file; /* true if field_value holds a filename for the value, false for plain value */
48 } Argument_VcField;
49
die(const char * message)50 static void die(const char *message)
51 {
52 FLAC__ASSERT(0 != message);
53 fprintf(stderr, "ERROR: %s\n", message);
54 exit(1);
55 }
56
local_strdup(const char * source)57 static char *local_strdup(const char *source)
58 {
59 char *ret;
60 FLAC__ASSERT(0 != source);
61 if(0 == (ret = strdup(source)))
62 die("out of memory during strdup()");
63 return ret;
64 }
65
parse_vorbis_comment_field(const char * field_ref,char ** field,char ** name,char ** value,unsigned * length,const char ** violation)66 static FLAC__bool parse_vorbis_comment_field(const char *field_ref, char **field, char **name, char **value, unsigned *length, const char **violation)
67 {
68 static const char * const violations[] = {
69 "field name contains invalid character",
70 "field contains no '=' character"
71 };
72
73 char *p, *q, *s;
74
75 if(0 != field)
76 *field = local_strdup(field_ref);
77
78 s = local_strdup(field_ref);
79
80 if(0 == (p = strchr(s, '='))) {
81 free(s);
82 *violation = violations[1];
83 return false;
84 }
85 *p++ = '\0';
86
87 for(q = s; *q; q++) {
88 if(*q < 0x20 || *q > 0x7d || *q == 0x3d) {
89 free(s);
90 *violation = violations[0];
91 return false;
92 }
93 }
94
95 *name = local_strdup(s);
96 *value = local_strdup(p);
97 *length = strlen(p);
98
99 free(s);
100 return true;
101 }
102
103 /* slight modification: no 'filename' arg, and errors are passed back in 'violation' instead of printed to stderr */
set_vc_field(FLAC__StreamMetadata * block,const Argument_VcField * field,FLAC__bool * needs_write,FLAC__bool raw,const char ** violation)104 static FLAC__bool set_vc_field(FLAC__StreamMetadata *block, const Argument_VcField *field, FLAC__bool *needs_write, FLAC__bool raw, const char **violation)
105 {
106 FLAC__StreamMetadata_VorbisComment_Entry entry;
107 char *converted = NULL;
108
109 FLAC__ASSERT(0 != block);
110 FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT);
111 FLAC__ASSERT(0 != field);
112 FLAC__ASSERT(0 != needs_write);
113
114 if(field->field_value_from_file) {
115 /* read the file into 'data' */
116 FILE *f = 0;
117 char *data = 0;
118 const FLAC__off_t size = grabbag__file_get_filesize(field->field_value);
119 if(size < 0) {
120 *violation = "can't open file for tag value";
121 return false;
122 }
123 if(size >= 0x100000) { /* magic arbitrary limit, actual format limit is near 16MB */
124 *violation = "file for tag value is too large";
125 return false;
126 }
127 if(0 == (data = malloc(size+1)))
128 die("out of memory allocating tag value");
129 data[size] = '\0';
130 if(0 == (f = flac_fopen(field->field_value, "rb")) || fread(data, 1, size, f) != (size_t)size) {
131 free(data);
132 if(f)
133 fclose(f);
134 *violation = "error while reading file for tag value";
135 return false;
136 }
137 fclose(f);
138 if(strlen(data) != (size_t)size) {
139 free(data);
140 *violation = "file for tag value has embedded NULs";
141 return false;
142 }
143
144 /* move 'data' into 'converted', converting to UTF-8 if necessary */
145 if(raw) {
146 converted = data;
147 }
148 else if(utf8_encode(data, &converted) >= 0) {
149 free(data);
150 }
151 else {
152 free(data);
153 *violation = "error converting file contents to UTF-8 for tag value";
154 return false;
155 }
156
157 /* create and entry and append it */
158 if(!FLAC__metadata_object_vorbiscomment_entry_from_name_value_pair(&entry, field->field_name, converted)) {
159 free(converted);
160 *violation = "file for tag value is not valid UTF-8";
161 return false;
162 }
163 free(converted);
164 if(!FLAC__metadata_object_vorbiscomment_append_comment(block, entry, /*copy=*/false)) {
165 *violation = "memory allocation failure";
166 return false;
167 }
168
169 *needs_write = true;
170 return true;
171 }
172 else {
173 FLAC__bool needs_free = false;
174 #ifdef _WIN32 /* everything in UTF-8 already. Must not alter */
175 entry.entry = (FLAC__byte *)field->field;
176 #else
177 if(raw) {
178 entry.entry = (FLAC__byte *)field->field;
179 }
180 else if(utf8_encode(field->field, &converted) >= 0) {
181 entry.entry = (FLAC__byte *)converted;
182 needs_free = true;
183 }
184 else {
185 *violation = "error converting comment to UTF-8";
186 return false;
187 }
188 #endif
189 entry.length = strlen((const char *)entry.entry);
190 if(!FLAC__format_vorbiscomment_entry_is_legal(entry.entry, entry.length)) {
191 if(needs_free)
192 free(converted);
193 /*
194 * our previous parsing has already established that the field
195 * name is OK, so it must be the field value
196 */
197 *violation = "tag value is not valid UTF-8";
198 return false;
199 }
200
201 if(!FLAC__metadata_object_vorbiscomment_append_comment(block, entry, /*copy=*/true)) {
202 if(needs_free)
203 free(converted);
204 *violation = "memory allocation failure";
205 return false;
206 }
207
208 *needs_write = true;
209 if(needs_free)
210 free(converted);
211 return true;
212 }
213 }
214
215 /*
216 * The rest of the code is novel
217 */
218
free_field(Argument_VcField * obj)219 static void free_field(Argument_VcField *obj)
220 {
221 if(0 != obj->field)
222 free(obj->field);
223 if(0 != obj->field_name)
224 free(obj->field_name);
225 if(0 != obj->field_value)
226 free(obj->field_value);
227 }
228
flac__vorbiscomment_add(FLAC__StreamMetadata * block,const char * comment,FLAC__bool value_from_file,FLAC__bool raw,const char ** violation)229 FLAC__bool flac__vorbiscomment_add(FLAC__StreamMetadata *block, const char *comment, FLAC__bool value_from_file, FLAC__bool raw, const char **violation)
230 {
231 Argument_VcField parsed;
232 FLAC__bool dummy;
233
234 FLAC__ASSERT(0 != block);
235 FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT);
236 FLAC__ASSERT(0 != comment);
237
238 memset(&parsed, 0, sizeof(parsed));
239
240 parsed.field_value_from_file = value_from_file;
241 if(!parse_vorbis_comment_field(comment, &(parsed.field), &(parsed.field_name), &(parsed.field_value), &(parsed.field_value_length), violation)) {
242 free_field(&parsed);
243 return false;
244 }
245
246 if(parsed.field_value_length > 0 && !set_vc_field(block, &parsed, &dummy, raw, violation)) {
247 free_field(&parsed);
248 return false;
249 }
250 else {
251 free_field(&parsed);
252 return true;
253 }
254 }
255