cloop driver (Johannes Schindelin)

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@1076 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 167 insertions, 0 deletions

diff --git a/block-cloop.c b/block-cloop.c
new file mode 100644
index 0000000..f22253d
--- /dev/null
+++ b/block-cloop.c
@@ -0,0 +1,167 @@
+/*
+ * QEMU System Emulator block driver
+ * 
+ * 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 <zlib.h>
+
+typedef struct BDRVCloopState {
+    int fd;
+    uint32_t block_size;
+    uint32_t n_blocks;
+    uint64_t* offsets;
+    uint32_t sectors_per_block;
+    uint32_t current_block;
+    char* compressed_block;
+    char* uncompressed_block;
+    z_stream zstream;
+} BDRVCloopState;
+
+static int cloop_probe(const uint8_t *buf, int buf_size, const char *filename)
+{
+    const char* magic_version_2_0="#!/bin/sh\n"
+	"#V2.0 Format\n"
+	"modprobe cloop file=$0 && mount -r -t iso9660 /dev/cloop $1\n";
+    int length=strlen(magic_version_2_0);
+    if(length>buf_size)
+	length=buf_size;
+    if(!memcmp(magic_version_2_0,buf,length))
+	return 2;
+    return 0;
+}
+
+static int cloop_open(BlockDriverState *bs, const char *filename)
+{
+    BDRVCloopState *s = bs->opaque;
+    uint32_t offsets_size,max_compressed_block_size=1,i;
+
+    s->fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE);
+    if (s->fd < 0)
+        return -1;
+    bs->read_only = 1;
+
+    /* read header */
+    if(lseek(s->fd,128,SEEK_SET)<0) {
+cloop_close:
+	close(s->fd);
+	return -1;
+    }
+    if(read(s->fd,&s->block_size,4)<4)
+	goto cloop_close;
+    s->block_size=be32_to_cpu(s->block_size);
+    if(read(s->fd,&s->n_blocks,4)<4)
+	goto cloop_close;
+    s->n_blocks=be32_to_cpu(s->n_blocks);
+
+    /* read offsets */
+    offsets_size=s->n_blocks*sizeof(uint64_t);
+    if(!(s->offsets=(uint64_t*)malloc(offsets_size)))
+	goto cloop_close;
+    if(read(s->fd,s->offsets,offsets_size)<offsets_size)
+	goto cloop_close;
+    for(i=0;i<s->n_blocks;i++) {
+	s->offsets[i]=be64_to_cpu(s->offsets[i]);
+	if(i>0) {
+	    uint32_t size=s->offsets[i]-s->offsets[i-1];
+	    if(size>max_compressed_block_size)
+		max_compressed_block_size=size;
+	}
+    }
+
+    /* initialize zlib engine */
+    if(!(s->compressed_block=(char*)malloc(max_compressed_block_size+1)))
+	goto cloop_close;
+    if(!(s->uncompressed_block=(char*)malloc(s->block_size)))
+	goto cloop_close;
+    if(inflateInit(&s->zstream) != Z_OK)
+	goto cloop_close;
+    s->current_block=s->n_blocks;
+    
+    s->sectors_per_block = s->block_size/512;
+    bs->total_sectors = s->n_blocks*s->sectors_per_block;
+    return 0;
+}
+
+static inline int cloop_read_block(BDRVCloopState *s,int block_num)
+{
+    if(s->current_block != block_num) {
+	int ret;
+        uint32_t bytes = s->offsets[block_num+1]-s->offsets[block_num];
+	    
+	lseek(s->fd, s->offsets[block_num], SEEK_SET);
+        ret = read(s->fd, s->compressed_block, bytes);
+        if (ret != bytes) 
+            return -1;
+	
+	s->zstream.next_in = s->compressed_block;
+	s->zstream.avail_in = bytes;
+	s->zstream.next_out = s->uncompressed_block;
+	s->zstream.avail_out = s->block_size;
+	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 != s->block_size)
+	    return -1;
+	
+	s->current_block = block_num;
+    }
+    return 0;
+}
+
+static int cloop_read(BlockDriverState *bs, int64_t sector_num, 
+                    uint8_t *buf, int nb_sectors)
+{
+    BDRVCloopState *s = bs->opaque;
+    int i;
+
+    for(i=0;i<nb_sectors;i++) {
+	uint32_t sector_offset_in_block=((sector_num+i)%s->sectors_per_block),
+	    block_num=(sector_num+i)/s->sectors_per_block;
+	if(cloop_read_block(s, block_num) != 0)
+	    return -1;
+	memcpy(buf+i*512,s->uncompressed_block+sector_offset_in_block*512,512);
+    }
+    return 0;
+}
+
+static void cloop_close(BlockDriverState *bs)
+{
+    BDRVCloopState *s = bs->opaque;
+    close(s->fd);
+    free(s->compressed_block);
+    free(s->uncompressed_block);
+    inflateEnd(&s->zstream);
+}
+
+BlockDriver bdrv_cloop = {
+    "cloop",
+    sizeof(BDRVCloopState),
+    cloop_probe,
+    cloop_open,
+    cloop_read,
+    NULL,
+    cloop_close,
+};
+
+