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
  33
  34 /*
  35  * This struct and the following 4 static functions are copied from
  36  * ../metaflac/.  Maybe someday there will be a convenience
  37  * library for Vorbis comment parsing.
  38  */
  39 typedef struct {
  40         char *field; /* the whole field as passed on the command line, i.e. "NAME=VALUE" */
  41         char *field_name;
  42         /* according to the vorbis spec, field values can contain \0 so simple C strings are not enough here */
  43         unsigned field_value_length;
  44         char *field_value;
  45         FLAC__bool field_value_from_file; /* true if field_value holds a filename for the value, false for plain value */
  46 } Argument_VcField;
  47
  48 static void die(const char *message)
  49 {
  50         FLAC__ASSERT(0 != message);
  51         fprintf(stderr, "ERROR: %s\n", message);
  52         exit(1);
  53 }
  54
  55 static char *local_strdup(const char *source)
  56 {
  57         char *ret;
  58         FLAC__ASSERT(0 != source);
  59         if(0 == (ret = strdup(source)))
  60                 die("out of memory during strdup()");
  61         return ret;
  62 }
  63
  64 static FLAC__bool parse_vorbis_comment_field(const char *field_ref, char **field, char **name, char **value, unsigned *length, const char **violation)
  65 {
  66         static const char * const violations[] = {
  67                 "field name contains invalid character",
  68                 "field contains no '=' character"
  69         };
  70
  71         char *p, *q, *s;
  72
  73         if(0 != field)
  74                 *field = local_strdup(field_ref);
  75
  76         s = local_strdup(field_ref);
  77
  78         if(0 == (p = strchr(s, '='))) {
  79                 free(s);
  80                 *violation = violations[1];
  81                 return false;
  82         }
  83         *p++ = '\0';
  84
  85         for(q = s; *q; q++) {
  86                 if(*q < 0x20 || *q > 0x7d || *q == 0x3d) {
  87                         free(s);
  88                         *violation = violations[0];
  89                         return false;
  90                 }
  91         }
  92
  93         *name = local_strdup(s);
  94         *value = local_strdup(p);
  95         *length = strlen(p);
  96
  97         free(s);
  98         return true;
  99 }
 100
 101 /* slight modification: no 'filename' arg, and errors are passed back in 'violation' instead of printed to stderr */
 102 static FLAC__bool set_vc_field(FLAC__StreamMetadata *block, const Argument_VcField *field, FLAC__bool *needs_write, FLAC__bool raw, const char **violation)
 103 {
 104         FLAC__StreamMetadata_VorbisComment_Entry entry;
 105         char *converted;
 106
 107         FLAC__ASSERT(0 != block);
 108         FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT);
 109         FLAC__ASSERT(0 != field);
 110         FLAC__ASSERT(0 != needs_write);
 111
 112         if(field->field_value_from_file) {
 113                 /* read the file into 'data' */
 114                 FILE *f = 0;
 115                 char *data = 0;
 116                 const off_t size = grabbag__file_get_filesize(field->field_value);
 117                 if(size < 0) {
 118                         *violation = "can't open file for tag value";
 119                         return false;
 120                 }
 121                 if(size >= 0x100000) { /* magic arbitrary limit, actual format limit is near 16MB */
 122                         *violation = "file for tag value is too large";
 123                         return false;
 124                 }
 125                 if(0 == (data = malloc(size+1)))
 126                         die("out of memory allocating tag value");
 127                 data[size] = '\0';
 128                 if(0 == (f = fopen(field->field_value, "rb")) || fread(data, 1, size, f) != (size_t)size) {
 129                         free(data);
 130                         if(f)
 131                                 fclose(f);
 132                         *violation = "error while reading file for tag value";
 133                         return false;
 134                 }
 135                 fclose(f);
 136                 if(strlen(data) != (size_t)size) {
 137                         free(data);
 138                         *violation = "file for tag value has embedded NULs";
 139                         return false;
 140                 }
 141
 142                 /* move 'data' into 'converted', converting to UTF-8 if necessary */
 143                 if(raw) {
 144                         converted = data;
 145                 }
 146                 else if(utf8_encode(data, &converted) >= 0) {
 147                         free(data);
 148                 }
 149                 else {
 150                         free(data);
 151                         *violation = "error converting file contents to UTF-8 for tag value";
 152                         return false;
 153                 }
 154
 155                 /* create and entry and append it */
 156                 if(!FLAC__metadata_object_vorbiscomment_entry_from_name_value_pair(&entry, field->field_name, converted)) {
 157                         free(converted);
 158                         *violation = "file for tag value is not valid UTF-8";
 159                         return false;
 160                 }
 161                 free(converted);
 162                 if(!FLAC__metadata_object_vorbiscomment_append_comment(block, entry, /*copy=*/false)) {
 163                         *violation = "memory allocation failure";
 164                         return false;
 165                 }
 166
 167                 *needs_write = true;
 168                 return true;
 169         }
 170         else {
 171                 FLAC__bool needs_free = false;
 172                 if(raw) {
 173                         entry.entry = (FLAC__byte *)field->field;
 174                 }
 175                 else if(utf8_encode(field->field, &converted) >= 0) {
 176                         entry.entry = (FLAC__byte *)converted;
 177                         needs_free = true;
 178                 }
 179                 else {
 180                         *violation = "error converting comment to UTF-8";
 181                         return false;
 182                 }
 183                 entry.length = strlen((const char *)entry.entry);
 184                 if(!FLAC__format_vorbiscomment_entry_is_legal(entry.entry, entry.length)) {
 185                         if(needs_free)
 186                                 free(converted);
 187                         /*
 188                          * our previous parsing has already established that the field
 189                          * name is OK, so it must be the field value
 190                          */
 191                         *violation = "tag value for is not valid UTF-8";
 192                         return false;
 193                 }
 194
 195                 if(!FLAC__metadata_object_vorbiscomment_append_comment(block, entry, /*copy=*/true)) {
 196                         if(needs_free)
 197                                 free(converted);
 198                         *violation = "memory allocation failure";
 199                         return false;
 200                 }
 201
 202                 *needs_write = true;
 203                 if(needs_free)
 204                         free(converted);
 205                 return true;
 206         }
 207 }
 208
 209 /*
 210  * The rest of the code is novel
 211  */
 212
 213 static void free_field(Argument_VcField *obj)
 214 {
 215         if(0 != obj->field)
 216                 free(obj->field);
 217         if(0 != obj->field_name)
 218                 free(obj->field_name);
 219         if(0 != obj->field_value)
 220                 free(obj->field_value);
 221 }
 222
 223 FLAC__bool flac__vorbiscomment_add(FLAC__StreamMetadata *block, const char *comment, FLAC__bool value_from_file, FLAC__bool raw, const char **violation)
 224 {
 225         Argument_VcField parsed;
 226         FLAC__bool dummy;
 227
 228         FLAC__ASSERT(0 != block);
 229         FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT);
 230         FLAC__ASSERT(0 != comment);
 231
 232         memset(&parsed, 0, sizeof(parsed));
 233
 234         parsed.field_value_from_file = value_from_file;
 235         if(!parse_vorbis_comment_field(comment, &(parsed.field), &(parsed.field_name), &(parsed.field_value), &(parsed.field_value_length), violation)) {
 236                 free_field(&parsed);
 237                 return false;
 238         }
 239
 240         if(!set_vc_field(block, &parsed, &dummy, raw, violation)) {
 241                 free_field(&parsed);
 242                 return false;
 243         }
 244         else {
 245                 free_field(&parsed);
 246                 return true;
 247         }
 248 }