/* * QEMU Block driver for DMG images * * Copyright (c) 2004 Johannes E. Schindelin * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ #include "qemu-common.h" #include "block_int.h" #include "bswap.h" #include "module.h" #include <zlib.h> typedef struct BDRVDMGState { CoMutex lock; /* each chunk contains a certain number of sectors, * offsets[i] is the offset in the .dmg file, * lengths[i] is the length of the compressed chunk, * sectors[i] is the sector beginning at offsets[i], * sectorcounts[i] is the number of sectors in that chunk, * the sectors array is ordered * 0<=i<n_chunks */ uint32_t n_chunks; uint32_t* types; uint64_t* offsets; uint64_t* lengths; uint64_t* sectors; uint64_t* sectorcounts; uint32_t current_chunk; uint8_t *compressed_chunk; uint8_t *uncompressed_chunk; z_stream zstream; } BDRVDMGState; static int dmg_probe(const uint8_t *buf, int buf_size, const char *filename) { int len=strlen(filename); if(len>4 && !strcmp(filename+len-4,".dmg")) return 2; return 0; } static off_t read_off(BlockDriverState *bs, int64_t offset) { uint64_t buffer; if (bdrv_pread(bs->file, offset, &buffer, 8) < 8) return 0; return be64_to_cpu(buffer); } static off_t read_uint32(BlockDriverState *bs, int64_t offset) { uint32_t buffer; if (bdrv_pread(bs->file, offset, &buffer, 4) < 4) return 0; return be32_to_cpu(buffer); } static int dmg_open(BlockDriverState *bs, int flags) { BDRVDMGState *s = bs->opaque; off_t info_begin,info_end,last_in_offset,last_out_offset; uint32_t count; uint32_t max_compressed_size=1,max_sectors_per_chunk=1,i; int64_t offset; bs->read_only = 1; s->n_chunks = 0; s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL; /* read offset of info blocks */ offset = bdrv_getlength(bs->file); if (offset < 0) { goto fail; } offset -= 0x1d8; info_begin = read_off(bs, offset); if (info_begin == 0) { goto fail; } if (read_uint32(bs, info_begin) != 0x100) { goto fail; } count = read_uint32(bs, info_begin + 4); if (count == 0) { goto fail; } info_end = info_begin + count; offset = info_begin + 0x100; /* read offsets */ last_in_offset = last_out_offset = 0; while (offset < info_end) { uint32_t type; count = read_uint32(bs, offset); if(count==0) goto fail; offset += 4; type = read_uint32(bs, offset); if (type == 0x6d697368 && count >= 244) { int new_size, chunk_count; offset += 4; offset += 200; chunk_count = (count-204)/40; new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count); s->types = g_realloc(s->types, new_size/2); s->offsets = g_realloc(s->offsets, new_size); s->lengths = g_realloc(s->lengths, new_size); s->sectors = g_realloc(s->sectors, new_size); s->sectorcounts = g_realloc(s->sectorcounts, new_size); for(i=s->n_chunks;i<s->n_chunks+chunk_count;i++) { s->types[i] = read_uint32(bs, offset); offset += 4; if(s->types[i]!=0x80000005 && s->types[i]!=1 && s->types[i]!=2) { if(s->types[i]==0xffffffff) { last_in_offset = s->offsets[i-1]+s->lengths[i-1]; last_out_offset = s->sectors[i-1]+s->sectorcounts[i-1]; } chunk_count--; i--; offset += 36; continue; } offset += 4; s->sectors[i] = last_out_offset+read_off(bs, offset); offset += 8; s->sectorcounts[i] = read_off(bs, offset); offset += 8; s->offsets[i] = last_in_offset+read_off(bs, offset); offset += 8; s->lengths[i] = read_off(bs, offset); offset += 8; if(s->lengths[i]>max_compressed_size) max_compressed_size = s->lengths[i]; if(s->sectorcounts[i]>max_sectors_per_chunk) max_sectors_per_chunk = s->sectorcounts[i]; } s->n_chunks+=chunk_count; } } /* initialize zlib engine */ s->compressed_chunk = g_malloc(max_compressed_size+1); s->uncompressed_chunk = g_malloc(512*max_sectors_per_chunk); if(inflateInit(&s->zstream) != Z_OK) goto fail; s->current_chunk = s->n_chunks; qemu_co_mutex_init(&s->lock); return 0; fail: return -1; } static inline int is_sector_in_chunk(BDRVDMGState* s, uint32_t chunk_num,int sector_num) { if(chunk_num>=s->n_chunks || s->sectors[chunk_num]>sector_num || s->sectors[chunk_num]+s->sectorcounts[chunk_num]<=sector_num) return 0; else return -1; } static inline uint32_t search_chunk(BDRVDMGState* s,int sector_num) { /* binary search */ uint32_t chunk1=0,chunk2=s->n_chunks,chunk3; while(chunk1!=chunk2) { chunk3 = (chunk1+chunk2)/2; if(s->sectors[chunk3]>sector_num) chunk2 = chunk3; else if(s->sectors[chunk3]+s->sectorcounts[chunk3]>sector_num) return chunk3; else chunk1 = chunk3; } return s->n_chunks; /* error */ } static inline int dmg_read_chunk(BlockDriverState *bs, int sector_num) { BDRVDMGState *s = bs->opaque; if(!is_sector_in_chunk(s,s->current_chunk,sector_num)) { int ret; uint32_t chunk = search_chunk(s,sector_num); if(chunk>=s->n_chunks) return -1; s->current_chunk = s->n_chunks; switch(s->types[chunk]) { case 0x80000005: { /* zlib compressed */ int i; /* we need to buffer, because only the chunk as whole can be * inflated. */ i=0; do { ret = bdrv_pread(bs->file, s->offsets[chunk] + i, s->compressed_chunk+i, s->lengths[chunk]-i); if(ret<0 && errno==EINTR) ret=0; i+=ret; } while(ret>=0 && ret+i<s->lengths[chunk]); if (ret != s->lengths[chunk]) return -1; s->zstream.next_in = s->compressed_chunk; s->zstream.avail_in = s->lengths[chunk]; s->zstream.next_out = s->uncompressed_chunk; s->zstream.avail_out = 512*s->sectorcounts[chunk]; ret = inflateReset(&s->zstream); if(ret != Z_OK) return -1; ret = inflate(&s->zstream, Z_FINISH); if(ret != Z_STREAM_END || s->zstream.total_out != 512*s->sectorcounts[chunk]) return -1; break; } case 1: /* copy */ ret = bdrv_pread(bs->file, s->offsets[chunk], s->uncompressed_chunk, s->lengths[chunk]); if (ret != s->lengths[chunk]) return -1; break; case 2: /* zero */ memset(s->uncompressed_chunk, 0, 512*s->sectorcounts[chunk]); break; } s->current_chunk = chunk; } return 0; } static int dmg_read(BlockDriverState *bs, int64_t sector_num, uint8_t *buf, int nb_sectors) { BDRVDMGState *s = bs->opaque; int i; for(i=0;i<nb_sectors;i++) { uint32_t sector_offset_in_chunk; if(dmg_read_chunk(bs, sector_num+i) != 0) return -1; sector_offset_in_chunk = sector_num+i-s->sectors[s->current_chunk]; memcpy(buf+i*512,s->uncompressed_chunk+sector_offset_in_chunk*512,512); } return 0; } static coroutine_fn int dmg_co_read(BlockDriverState *bs, int64_t sector_num, uint8_t *buf, int nb_sectors) { int ret; BDRVDMGState *s = bs->opaque; qemu_co_mutex_lock(&s->lock); ret = dmg_read(bs, sector_num, buf, nb_sectors); qemu_co_mutex_unlock(&s->lock); return ret; } static void dmg_close(BlockDriverState *bs) { BDRVDMGState *s = bs->opaque; if(s->n_chunks>0) { free(s->types); free(s->offsets); free(s->lengths); free(s->sectors); free(s->sectorcounts); } free(s->compressed_chunk); free(s->uncompressed_chunk); inflateEnd(&s->zstream); } static BlockDriver bdrv_dmg = { .format_name = "dmg", .instance_size = sizeof(BDRVDMGState), .bdrv_probe = dmg_probe, .bdrv_open = dmg_open, .bdrv_read = dmg_co_read, .bdrv_close = dmg_close, }; static void bdrv_dmg_init(void) { bdrv_register(&bdrv_dmg); } block_init(bdrv_dmg_init);