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blockdev: Fix drive_add for drives without media

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Watch this:

    (qemu) drive_add 0 if=none
    (qemu) info block
    none0: type=hd removable=0 [not inserted]
    (qemu) drive_del none0
    Segmentation fault (core dumped)

add_init_drive() is confused about drive_init()'s failure modes, and
cleans up when it shouldn't.  This leaves the DriveInfo with member
opts dangling.  drive_del attempts to free it, and dies.

drive_init() behaves as follows:

* If it created a drive with media, it returns its DriveInfo.

* If it created a drive without media, it clears *fatal_error and
  returns NULL.

* If it couldn't create a drive, it sets *fatal_error and returns
  NULL.

Of its three callers:

* drive_init_func() is correct.

* usb_msd_init() assumes drive_init() failed when it returns NULL.
  This is correct only because it always passes option "file", and
  "drive without media" can't happen then.

* add_init_drive() assumes drive_init() failed when it returns NULL.
  This is incorrect.

Clean up drive_init() to return NULL on failure and only on failure.
Drop its parameter fatal_error.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Markus Armbruster 2011-01-28 11:21:46 +01:00 • committed by Kevin Wolf
parent 5645b0f4f2
commit 319ae529b8
5 changed files with 7 additions and 18 deletions
Download patch file Download diff file Expand all files Collapse all files

8
blockdev.c
View file

@ -203,7 +203,7 @@ static int parse_block_error_action(const char *buf, int is_read)
}
}
DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi, int *fatal_error)
DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
{
const char *buf;
const char *file = NULL;
@ -225,8 +225,6 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi, int *fatal_error)
int snapshot = 0;
int ret;
*fatal_error = 1;
translation = BIOS_ATA_TRANSLATION_AUTO;
if (default_to_scsi) {
@ -499,8 +497,7 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi, int *fatal_error)
abort();
}
if (!file || !*file) {
*fatal_error = 0;
return NULL;
return dinfo;
}
if (snapshot) {
/* always use cache=unsafe with snapshot */
@ -529,7 +526,6 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi, int *fatal_error)
if (bdrv_key_required(dinfo->bdrv))
autostart = 0;
*fatal_error = 0;
return dinfo;
}