.dmg disk image format support (Johannes Schindelin)

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@1171 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 293 insertions, 0 deletions

diff --git a/block-dmg.c b/block-dmg.c
new file mode 100644
index 000000000..af8b67b7a
--- /dev/null
+++ b/block-dmg.c
@@ -0,0 +1,293 @@
+/*
+ * 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;
+    char* compressed_chunk;
+    char* 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);
+	return -1;
+    }
+    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) {
+	count = read_uint32(s->fd);
+	if(count==0)
+	    goto dmg_close;
+	uint32_t 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=(char*)malloc(max_compressed_size+1)))
+	goto dmg_close;
+    if(!(s->uncompressed_chunk=(char*)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,
+};
+