[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PATCH 05/32] block: make bdrv_find_backing_image compare c
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH 05/32] block: make bdrv_find_backing_image compare canonical filenames |
Date: |
Wed, 24 Oct 2012 11:50:29 +0200 |
From: Jeff Cody <address@hidden>
Currently, bdrv_find_backing_image compares bs->backing_file with
what is passed in as a backing_file name. Mismatches may occur,
however, when bs->backing_file and backing_file are not both
absolute or relative.
Use path_combine() to make sure any relative backing filenames are
relative to the current image filename being searched, and then use
realpath() to make all comparisons based on absolute filenames.
If either backing_file or bs->backing_file is determine to be a
protocol, then no filename normalization is performed.
This also changes bdrv_find_backing_image to no longer be recursive,
but iterative.
Signed-off-by: Jeff Cody <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
Signed-off-by: Kevin Wolf <address@hidden>
---
block.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++++------
1 files changed, 54 insertions(+), 6 deletions(-)
diff --git a/block.c b/block.c
index e95f613..5e7fc9e 100644
--- a/block.c
+++ b/block.c
@@ -3123,22 +3123,70 @@ int bdrv_snapshot_load_tmp(BlockDriverState *bs,
return -ENOTSUP;
}
+/* backing_file can either be relative, or absolute, or a protocol. If it is
+ * relative, it must be relative to the chain. So, passing in bs->filename
+ * from a BDS as backing_file should not be done, as that may be relative to
+ * the CWD rather than the chain. */
BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
const char *backing_file)
{
- if (!bs->drv) {
+ char *filename_full = NULL;
+ char *backing_file_full = NULL;
+ char *filename_tmp = NULL;
+ int is_protocol = 0;
+ BlockDriverState *curr_bs = NULL;
+ BlockDriverState *retval = NULL;
+
+ if (!bs || !bs->drv || !backing_file) {
return NULL;
}
- if (bs->backing_hd) {
- if (strcmp(bs->backing_file, backing_file) == 0) {
- return bs->backing_hd;
+ filename_full = g_malloc(PATH_MAX);
+ backing_file_full = g_malloc(PATH_MAX);
+ filename_tmp = g_malloc(PATH_MAX);
+
+ is_protocol = path_has_protocol(backing_file);
+
+ for (curr_bs = bs; curr_bs->backing_hd; curr_bs = curr_bs->backing_hd) {
+
+ /* If either of the filename paths is actually a protocol, then
+ * compare unmodified paths; otherwise make paths relative */
+ if (is_protocol || path_has_protocol(curr_bs->backing_file)) {
+ if (strcmp(backing_file, curr_bs->backing_file) == 0) {
+ retval = curr_bs->backing_hd;
+ break;
+ }
} else {
- return bdrv_find_backing_image(bs->backing_hd, backing_file);
+ /* If not an absolute filename path, make it relative to the
current
+ * image's filename path */
+ path_combine(filename_tmp, PATH_MAX, curr_bs->filename,
+ backing_file);
+
+ /* We are going to compare absolute pathnames */
+ if (!realpath(filename_tmp, filename_full)) {
+ continue;
+ }
+
+ /* We need to make sure the backing filename we are comparing
against
+ * is relative to the current image filename (or absolute) */
+ path_combine(filename_tmp, PATH_MAX, curr_bs->filename,
+ curr_bs->backing_file);
+
+ if (!realpath(filename_tmp, backing_file_full)) {
+ continue;
+ }
+
+ if (strcmp(backing_file_full, filename_full) == 0) {
+ retval = curr_bs->backing_hd;
+ break;
+ }
}
}
- return NULL;
+ g_free(filename_full);
+ g_free(backing_file_full);
+ g_free(filename_tmp);
+ return retval;
}
int bdrv_get_backing_file_depth(BlockDriverState *bs)
--
1.7.6.5
- [Qemu-devel] [PULL 00/32] Block patches, Kevin Wolf, 2012/10/24
- [Qemu-devel] [PATCH 01/32] qemu-img: Fix division by zero for zero size images, Kevin Wolf, 2012/10/24
- [Qemu-devel] [PATCH 02/32] qemu-iotests: Test qemu-img operation on zero size image, Kevin Wolf, 2012/10/24
- [Qemu-devel] [PATCH 05/32] block: make bdrv_find_backing_image compare canonical filenames,
Kevin Wolf <=
- [Qemu-devel] [PATCH 03/32] qmp: fix __accept() in qmp.py, Kevin Wolf, 2012/10/24
- [Qemu-devel] [PATCH 07/32] qemu-iotests: add relative backing file tests for block-commit (040), Kevin Wolf, 2012/10/24
- [Qemu-devel] [PATCH 04/32] qemu-img rebase: use empty string to rebase without backing file, Kevin Wolf, 2012/10/24
- [Qemu-devel] [PATCH 08/32] qemu-img: Add --backing-chain option to info command, Kevin Wolf, 2012/10/24
- [Qemu-devel] [PATCH 06/32] block: in commit, determine base image from the top image, Kevin Wolf, 2012/10/24
- [Qemu-devel] [PATCH 12/32] monitor: Allow add-fd to any specified fd set, Kevin Wolf, 2012/10/24
- [Qemu-devel] [PATCH 10/32] qemu-img: document 'info --backing-chain', Kevin Wolf, 2012/10/24
- [Qemu-devel] [PATCH 11/32] block: bdrv_create(): don't leak cco.filename on error, Kevin Wolf, 2012/10/24
- [Qemu-devel] [PATCH 14/32] monitor: Prevent removing fd from set during init, Kevin Wolf, 2012/10/24
- [Qemu-devel] [PATCH 09/32] qemu-iotests: Add 043 backing file chain infinite loop test, Kevin Wolf, 2012/10/24