/* * Copyright (C) 2003-2009 The Music Player Daemon Project * http://www.musicpd.org * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #include "riff.h" #include <glib.h> #include <stdint.h> #include <sys/types.h> #include <sys/stat.h> #include <unistd.h> #include <errno.h> #include <string.h> #undef G_LOG_DOMAIN #define G_LOG_DOMAIN "riff" struct riff_header { char id[4]; uint32_t size; char format[4]; }; struct riff_chunk_header { char id[4]; uint32_t size; }; size_t riff_seek_id3(FILE *file) { int ret; struct stat st; struct riff_header header; struct riff_chunk_header chunk; size_t size; /* determine the file size */ ret = fstat(fileno(file), &st); if (ret < 0) { g_warning("Failed to stat file descriptor: %s", strerror(errno)); return 0; } /* seek to the beginning and read the RIFF header */ ret = fseek(file, 0, SEEK_SET); if (ret != 0) { g_warning("Failed to seek: %s", g_strerror(errno)); return 0; } size = fread(&header, sizeof(header), 1, file); if (size != 1 || memcmp(header.id, "RIFF", 4) != 0 || GUINT32_FROM_LE(header.size) > (uint32_t)st.st_size) /* not a RIFF file */ return 0; while (true) { /* read the chunk header */ size = fread(&chunk, sizeof(chunk), 1, file); if (size != 1) return 0; size = GUINT32_FROM_LE(chunk.size); if (size > G_MAXINT32) /* too dangerous, bail out: possible integer underflow when casting to off_t */ return 0; if (size % 2 != 0) /* pad byte */ ++size; if (memcmp(chunk.id, "id3 ", 4) == 0) /* found it! */ return size; ret = fseek(file, size, SEEK_CUR); if (ret != 0) return 0; } }