[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen master] tools/blktap2: Fix array initialisers for tapdisk_disk_{types, drivers}[]
commit 05fc4ef8ae3e99e8a26cffb2bc9ea22c306fb5fe Author: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> AuthorDate: Wed Apr 27 11:23:04 2016 +0100 Commit: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> CommitDate: Wed Apr 27 20:31:08 2016 +0100 tools/blktap2: Fix array initialisers for tapdisk_disk_{types,drivers}[] Clang points out: tapdisk-disktype.c:117:2: error: initializer overrides prior initialization of this subobject [-Werror,-Winitializer-overrides] 0, ^ tapdisk-disktype.c:115:23: note: previous initialization is here [DISK_TYPE_VINDEX] = &vhd_index_disk, ^~~~~~~~~~~~~~~ Mixing different initialiser styles should be avoided; The actual behaviour is different to the expected behaviour. This specific example has been broken since its introduction in c/s 7b4dea554 "blktap2: Fix tapdisk disktype issues" in 2010, and is caused by the '#if 0' block removing &tapdisk_{sync,vmdk}. First of all, remove what were intended to be trailing NULL entries in tapdisk_disk_{types,drivers}[], making consistent use of Designated Initialisers for the initialisation. This requires changing the loop in tapdisk_disktype_find() to be based on the number of elements in tapdisk_disk_types[], rather than looking for the first NULL. This fixes a latent bug, as the use of Designated Initializers causes to intermediate zero entries if not all indices are explicitly specified. There is a second latent bug where tapdisk_disktype_find() assumes that tapdisk_disk_drivers[] has at least as many entries as tapdisk_disk_types[]. This is not the case and tapdisk_disk_drivers[] had one entry fewer than tapdisk_disk_types[], but the NULL loop bound prevented an out-of-bounds read of tapdisk_disk_drivers[]. Fix the issue by explicitly declaring tapdisk_disk_drivers[] to have the same number of entries as tapdisk_disk_types[]. Finally, this leads to a linker error. It turns out that tapdisk_vhd_index doesn't exist, and I can't find any evidence in the source history to suggest that it ever did. I can only presume that it would have been #if 0'd out like tapdisk_sync and tapdisk_vmdk had it not been for this bug preventing a build failure. Drop all three. No functional change, but only because of the specific layout of tapdisk_disk_types[]. Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx> Release-acked-by: Wei Liu <wei.liu2@xxxxxxxxxx> Reviewed-by: Doug Goldstein <cardoe@xxxxxxxxxx> --- tools/blktap2/drivers/tapdisk-disktype.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-) diff --git a/tools/blktap2/drivers/tapdisk-disktype.c b/tools/blktap2/drivers/tapdisk-disktype.c index e9a6890..e89d364 100644 --- a/tools/blktap2/drivers/tapdisk-disktype.c +++ b/tools/blktap2/drivers/tapdisk-disktype.c @@ -33,6 +33,8 @@ #include "tapdisk-disktype.h" #include "tapdisk-message.h" +#define ARRAY_SIZE(a) (sizeof (a) / sizeof *(a)) + static const disk_info_t aio_disk = { "aio", "raw image (aio)", @@ -112,35 +114,25 @@ const disk_info_t *tapdisk_disk_types[] = { [DISK_TYPE_LOG] = &log_disk, [DISK_TYPE_VINDEX] = &vhd_index_disk, [DISK_TYPE_REMUS] = &remus_disk, - 0, }; extern struct tap_disk tapdisk_aio; -extern struct tap_disk tapdisk_sync; -extern struct tap_disk tapdisk_vmdk; extern struct tap_disk tapdisk_vhdsync; extern struct tap_disk tapdisk_vhd; extern struct tap_disk tapdisk_ram; extern struct tap_disk tapdisk_qcow; extern struct tap_disk tapdisk_block_cache; -extern struct tap_disk tapdisk_vhd_index; extern struct tap_disk tapdisk_log; extern struct tap_disk tapdisk_remus; -const struct tap_disk *tapdisk_disk_drivers[] = { +const struct tap_disk *tapdisk_disk_drivers[ARRAY_SIZE(tapdisk_disk_types)] = { [DISK_TYPE_AIO] = &tapdisk_aio, -#if 0 - [DISK_TYPE_SYNC] = &tapdisk_sync, - [DISK_TYPE_VMDK] = &tapdisk_vmdk, -#endif [DISK_TYPE_VHD] = &tapdisk_vhd, [DISK_TYPE_RAM] = &tapdisk_ram, [DISK_TYPE_QCOW] = &tapdisk_qcow, [DISK_TYPE_BLOCK_CACHE] = &tapdisk_block_cache, - [DISK_TYPE_VINDEX] = &tapdisk_vhd_index, [DISK_TYPE_LOG] = &tapdisk_log, [DISK_TYPE_REMUS] = &tapdisk_remus, - 0, }; int @@ -149,7 +141,11 @@ tapdisk_disktype_find(const char *name) const disk_info_t *info; int i; - for (i = 0; info = tapdisk_disk_types[i], info != NULL; ++i) { + for (i = 0; i < ARRAY_SIZE(tapdisk_disk_types); ++i) { + info = tapdisk_disk_types[i]; + if (!info) + continue; + if (strcmp(name, info->name)) continue; -- generated by git-patchbot for /home/xen/git/xen.git#master _______________________________________________ Xen-changelog mailing list Xen-changelog@xxxxxxxxxxxxx http://lists.xensource.com/xen-changelog
|
![]() |
Lists.xenproject.org is hosted with RackSpace, monitoring our |