src/flac/vorbiscomment.c

   1 /* flac - Command-line FLAC encoder/decoder
   2  * Copyright (C) 2002-2009  Josh Coalson
   3  * Copyright (C) 2011-2013  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 #if 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
  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
  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
  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 */
 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;
 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 for 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
 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
 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(!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 }