src/flac/vorbiscomment.c

   1 /* flac - Command-line FLAC encoder/decoder
   2  * Copyright (C) 2002,2003,2004,2005,2006,2007,2008,2009  Josh Coalson
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #if HAVE_CONFIG_H
  20 #  include <config.h>
  21 #endif
  22
  23 #include "vorbiscomment.h"
  24 #include "FLAC/assert.h"
  25 #include "FLAC/metadata.h"
  26 #include "share/grabbag.h" /* for grabbag__file_get_filesize() */
  27 #include "share/utf8.h"
  28 #include <ctype.h>
  29 #include <stdio.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32 #include "share/compat.h"
  33
  34
  35 /*
  36  * This struct and the following 4 static functions are copied from
  37  * ../metaflac/.  Maybe someday there will be a convenience
  38  * library for Vorbis comment parsing.
  39  */
  40 typedef struct {
  41         char *field; /* the whole field as passed on the command line, i.e. "NAME=VALUE" */
  42         char *field_name;
  43         /* according to the vorbis spec, field values can contain \0 so simple C strings are not enough here */
  44         unsigned field_value_length;
  45         char *field_value;
  46         FLAC__bool field_value_from_file; /* true if field_value holds a filename for the value, false for plain value */
  47 } Argument_VcField;
  48
  49 static void die(const char *message)
  50 {
  51         FLAC__ASSERT(0 != message);
  52         fprintf(stderr, "ERROR: %s\n", message);
  53         exit(1);
  54 }
  55
  56 static char *local_strdup(const char *source)
  57 {
  58         char *ret;
  59         FLAC__ASSERT(0 != source);
  60         if(0 == (ret = strdup(source)))
  61                 die("out of memory during strdup()");
  62         return ret;
  63 }
  64
  65 static FLAC__bool parse_vorbis_comment_field(const char *field_ref, char **field, char **name, char **value, unsigned *length, const char **violation)
  66 {
  67         static const char * const violations[] = {
  68                 "field name contains invalid character",
  69                 "field contains no '=' character"
  70         };
  71
  72         char *p, *q, *s;
  73
  74         if(0 != field)
  75                 *field = local_strdup(field_ref);
  76
  77         s = local_strdup(field_ref);
  78
  79         if(0 == (p = strchr(s, '='))) {
  80                 free(s);
  81                 *violation = violations[1];
  82                 return false;
  83         }
  84         *p++ = '\0';
  85
  86         for(q = s; *q; q++) {
  87                 if(*q < 0x20 || *q > 0x7d || *q == 0x3d) {
  88                         free(s);
  89                         *violation = violations[0];
  90                         return false;
  91                 }
  92         }
  93
  94         *name = local_strdup(s);
  95         *value = local_strdup(p);
  96         *length = strlen(p);
  97
  98         free(s);
  99         return true;
 100 }
 101
 102 /* slight modification: no 'filename' arg, and errors are passed back in 'violation' instead of printed to stderr */
 103 static FLAC__bool set_vc_field(FLAC__StreamMetadata *block, const Argument_VcField *field, FLAC__bool *needs_write, FLAC__bool raw, const char **violation)
 104 {
 105         FLAC__StreamMetadata_VorbisComment_Entry entry;
 106         char *converted;
 107
 108         FLAC__ASSERT(0 != block);
 109         FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT);
 110         FLAC__ASSERT(0 != field);
 111         FLAC__ASSERT(0 != needs_write);
 112
 113         if(field->field_value_from_file) {
 114                 /* read the file into 'data' */
 115                 FILE *f = 0;
 116                 char *data = 0;
 117                 const FLAC__off_t size = grabbag__file_get_filesize(field->field_value);
 118                 if(size < 0) {
 119                         *violation = "can't open file for tag value";
 120                         return false;
 121                 }
 122                 if(size >= 0x100000) { /* magic arbitrary limit, actual format limit is near 16MB */
 123                         *violation = "file for tag value is too large";
 124                         return false;
 125                 }
 126                 if(0 == (data = malloc(size+1)))
 127                         die("out of memory allocating tag value");
 128                 data[size] = '\0';
 129                 if(0 == (f = fopen(field->field_value, "rb")) || fread(data, 1, size, f) != (size_t)size) {
 130                         free(data);
 131                         if(f)
 132                                 fclose(f);
 133                         *violation = "error while reading file for tag value";
 134                         return false;
 135                 }
 136                 fclose(f);
 137                 if(strlen(data) != (size_t)size) {
 138                         free(data);
 139                         *violation = "file for tag value has embedded NULs";
 140                         return false;
 141                 }
 142
 143                 /* move 'data' into 'converted', converting to UTF-8 if necessary */
 144                 if(raw) {
 145                         converted = data;
 146                 }
 147                 else if(utf8_encode(data, &converted) >= 0) {
 148                         free(data);
 149                 }
 150                 else {
 151                         free(data);
 152                         *violation = "error converting file contents to UTF-8 for tag value";
 153                         return false;
 154                 }
 155
 156                 /* create and entry and append it */
 157                 if(!FLAC__metadata_object_vorbiscomment_entry_from_name_value_pair(&entry, field->field_name, converted)) {
 158                         free(converted);
 159                         *violation = "file for tag value is not valid UTF-8";
 160                         return false;
 161                 }
 162                 free(converted);
 163                 if(!FLAC__metadata_object_vorbiscomment_append_comment(block, entry, /*copy=*/false)) {
 164                         *violation = "memory allocation failure";
 165                         return false;
 166                 }
 167
 168                 *needs_write = true;
 169                 return true;
 170         }
 171         else {
 172                 FLAC__bool needs_free = false;
 173                 if(raw) {
 174                         entry.entry = (FLAC__byte *)field->field;
 175                 }
 176                 else if(utf8_encode(field->field, &converted) >= 0) {
 177                         entry.entry = (FLAC__byte *)converted;
 178                         needs_free = true;
 179                 }
 180                 else {
 181                         *violation = "error converting comment to UTF-8";
 182                         return false;
 183                 }
 184                 entry.length = strlen((const char *)entry.entry);
 185                 if(!FLAC__format_vorbiscomment_entry_is_legal(entry.entry, entry.length)) {
 186                         if(needs_free)
 187                                 free(converted);
 188                         /*
 189                          * our previous parsing has already established that the field
 190                          * name is OK, so it must be the field value
 191                          */
 192                         *violation = "tag value for is not valid UTF-8";
 193                         return false;
 194                 }
 195
 196                 if(!FLAC__metadata_object_vorbiscomment_append_comment(block, entry, /*copy=*/true)) {
 197                         if(needs_free)
 198                                 free(converted);
 199                         *violation = "memory allocation failure";
 200                         return false;
 201                 }
 202
 203                 *needs_write = true;
 204                 if(needs_free)
 205                         free(converted);
 206                 return true;
 207         }
 208 }
 209
 210 /*
 211  * The rest of the code is novel
 212  */
 213
 214 static void free_field(Argument_VcField *obj)
 215 {
 216         if(0 != obj->field)
 217                 free(obj->field);
 218         if(0 != obj->field_name)
 219                 free(obj->field_name);
 220         if(0 != obj->field_value)
 221                 free(obj->field_value);
 222 }
 223
 224 FLAC__bool flac__vorbiscomment_add(FLAC__StreamMetadata *block, const char *comment, FLAC__bool value_from_file, FLAC__bool raw, const char **violation)
 225 {
 226         Argument_VcField parsed;
 227         FLAC__bool dummy;
 228
 229         FLAC__ASSERT(0 != block);
 230         FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT);
 231         FLAC__ASSERT(0 != comment);
 232
 233         memset(&parsed, 0, sizeof(parsed));
 234
 235         parsed.field_value_from_file = value_from_file;
 236         if(!parse_vorbis_comment_field(comment, &(parsed.field), &(parsed.field_name), &(parsed.field_value), &(parsed.field_value_length), violation)) {
 237                 free_field(&parsed);
 238                 return false;
 239         }
 240
 241         if(!set_vc_field(block, &parsed, &dummy, raw, violation)) {
 242                 free_field(&parsed);
 243                 return false;
 244         }
 245         else {
 246                 free_field(&parsed);
 247                 return true;
 248         }
 249 }