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allow read only images

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git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@299 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
bellard 2003-06-30 23:17:31 +00:00
parent 305034817d
commit 0849bf0821
1 changed files with 12 additions and 3 deletions
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9
block.c
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@ -44,6 +44,7 @@
struct BlockDriverState {
int fd;
int64_t total_sectors;
int read_only;
};
BlockDriverState *bdrv_open(const char *filename)
@ -55,12 +56,17 @@ BlockDriverState *bdrv_open(const char *filename)
bs = malloc(sizeof(BlockDriverState));
if(!bs)
return NULL;
bs->read_only = 0;
fd = open(filename, O_RDWR);
if (fd < 0) {
fd = open(filename, O_RDONLY);
if (fd < 0) {
close(fd);
free(bs);
return NULL;
}
bs->read_only = 1;
}
size = lseek64(fd, 0, SEEK_END);
bs->total_sectors = size / 512;
bs->fd = fd;
@ -93,6 +99,9 @@ int bdrv_write(BlockDriverState *bs, int64_t sector_num,
{
int ret;
if (bs->read_only)
return -1;
lseek64(bs->fd, sector_num * 512, SEEK_SET);
ret = write(bs->fd, buf, nb_sectors * 512);
if (ret != nb_sectors * 512)