block: add block driver read only whitelist

We may want to include a driver in the whitelist for read only tasks
such as diagnosing or exporting guest data (with libguestfs as a good
example). This patch introduces a readonly whitelist option, and for
backward compatibility, the old configure option --block-drv-whitelist
is now an alias to rw whitelist.

Drivers in readonly list is only permitted to open file readonly, and
returns -ENOTSUP for RW opening.

E.g. To include vmdk readonly, and others read+write:
    ./configure --target-list=x86_64-softmmu \
                --block-drv-rw-whitelist=qcow2,raw,file,qed \
                --block-drv-ro-whitelist=vmdk

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/block/block.h b/include/block/block.h
index 1251c5cf9f..5604418a6a 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -124,7 +124,8 @@ void bdrv_init(void);
 void bdrv_init_with_whitelist(void);
 BlockDriver *bdrv_find_protocol(const char *filename);
 BlockDriver *bdrv_find_format(const char *format_name);
-BlockDriver *bdrv_find_whitelisted_format(const char *format_name);
+BlockDriver *bdrv_find_whitelisted_format(const char *format_name,
+                                          bool readonly);
 int bdrv_create(BlockDriver *drv, const char* filename,
     QEMUOptionParameter *options);
 int bdrv_create_file(const char* filename, QEMUOptionParameter *options);