blockdev: Fix drive_add for drives without media

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

9
vl.c
View file

@ -631,13 +631,8 @@ static int bt_parse(const char *opt)
static int drive_init_func(QemuOpts *opts, void *opaque)
{
int *use_scsi = opaque;
int fatal_error = 0;
if (drive_init(opts, *use_scsi, &fatal_error) == NULL) {
if (fatal_error)
return 1;
}
return 0;
return drive_init(opts, *use_scsi) == NULL;
}
static int drive_enable_snapshot(QemuOpts *opts, void *opaque)
@ -666,7 +661,7 @@ static void default_drive(int enable, int snapshot, int use_scsi,
if (snapshot) {
drive_enable_snapshot(opts, NULL);
}
if (drive_init_func(opts, &use_scsi)) {
if (!drive_init(opts, use_scsi)) {
exit(1);
}
}