/* * 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 "vl.h" #include "block_int.h" #include "bswap.h" #include <zlib.h> typedef struct BDRVDMGState { int fd; /* 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(int fd) { uint64_t buffer; if(read(fd,&buffer,8)<8) return 0; return be64_to_cpu(buffer); } static off_t read_uint32(int fd) { uint32_t buffer; if(read(fd,&buffer,4)<4) return 0; return be32_to_cpu(buffer); } static int dmg_open(BlockDriverState *bs, const char *filename) { 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; s->fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE); if (s->fd < 0) return -1; bs->read_only = 1; s->n_chunks = 0; s->offsets = s->lengths = s->sectors = s->sectorcounts = 0; /* read offset of info blocks */ if(lseek(s->fd,-0x1d8,SEEK_END)<0) { dmg_close: close(s->fd); /* open raw instead */ bs->drv=&bdrv_raw; return bs->drv->bdrv_open(bs,filename); } info_begin=read_off(s->fd); if(info_begin==0) goto dmg_close; if(lseek(s->fd,info_begin,SEEK_SET)<0) goto dmg_close; if(read_uint32(s->fd)!=0x100) goto dmg_close; if((count = read_uint32(s->fd))==0) goto dmg_close; info_end = info_begin+count; if(lseek(s->fd,0xf8,SEEK_CUR)<0) goto dmg_close; /* read offsets */ last_in_offset = last_out_offset = 0; while(lseek(s->fd,0,SEEK_CUR)<info_end) { uint32_t type; count = read_uint32(s->fd); if(count==0) goto dmg_close; type = read_uint32(s->fd); if(type!=0x6d697368 || count<244) lseek(s->fd,count-4,SEEK_CUR); else { int new_size, chunk_count; if(lseek(s->fd,200,SEEK_CUR)<0) goto dmg_close; chunk_count = (count-204)/40; new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count); s->types = realloc(s->types, new_size/2); s->offsets = realloc(s->offsets, new_size); s->lengths = realloc(s->lengths, new_size); s->sectors = realloc(s->sectors, new_size); s->sectorcounts = realloc(s->sectorcounts, new_size); for(i=s->n_chunks;i<s->n_chunks+chunk_count;i++) { s->types[i] = read_uint32(s->fd); 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--; if(lseek(s->fd,36,SEEK_CUR)<0) goto dmg_close; continue; } read_uint32(s->fd); s->sectors[i] = last_out_offset+read_off(s->fd); s->sectorcounts[i] = read_off(s->fd); s->offsets[i] = last_in_offset+read_off(s->fd); s->lengths[i] = read_off(s->fd); 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 */ if(!(s->compressed_chunk = malloc(max_compressed_size+1))) goto dmg_close; if(!(s->uncompressed_chunk = malloc(512*max_sectors_per_chunk))) goto dmg_close; if(inflateInit(&s->zstream) != Z_OK) goto dmg_close; s->current_chunk = s->n_chunks; return 0; } 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(BDRVDMGState *s,int sector_num) { 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; ret = lseek(s->fd, s->offsets[chunk], SEEK_SET); if(ret<0) return -1; /* we need to buffer, because only the chunk as whole can be * inflated. */ i=0; do { ret = read(s->fd, 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 = read(s->fd, 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(s, 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 void dmg_close(BlockDriverState *bs) { BDRVDMGState *s = bs->opaque; close(s->fd); 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); } BlockDriver bdrv_dmg = { "dmg", sizeof(BDRVDMGState), dmg_probe, dmg_open, dmg_read, NULL, dmg_close, };