Adding to Block Drivers the capability of being able to clean up
its created files can be useful in certain situations. For the
LUKS driver, for instance, a failure in one of its authentication
steps can leave files in the host that weren't there before.
This patch adds the 'bdrv_co_delete_file' interface to block
drivers and add it to the 'file' driver in file-posix.c. The
implementation is given by 'raw_co_delete_file'. The helper
'bdrv_path_is_regular_file' is being used only in raw_co_delete_file
at this moment, but it will be used inside LUKS in a later patch.
Foreseeing this future use, let's put it in block.c and make it
public.
Suggested-by: Daniel P. Berrangé <berra...@redhat.com>
Signed-off-by: Daniel Henrique Barboza <danielhb...@gmail.com>
---
block.c | 11 +++++++++++
block/file-posix.c | 28 ++++++++++++++++++++++++++++
include/block/block.h | 1 +
include/block/block_int.h | 6 ++++++
4 files changed, 46 insertions(+)
diff --git a/block.c b/block.c
index c139540f2b..6e2b0f528d 100644
--- a/block.c
+++ b/block.c
@@ -621,6 +621,17 @@ int get_tmp_filename(char *filename, int size)
#endif
}
+/**
+ * Helper that checks if a given string represents a regular
+ * local file.
+ */
+bool bdrv_path_is_regular_file(const char *path)
+{
+ struct stat st;
+
+ return (stat(path, &st) == 0) && S_ISREG(st.st_mode);
+}
+
/*
* Detect host devices. By convention, /dev/cdrom[N] is always
* recognized as a host CDROM.
diff --git a/block/file-posix.c b/block/file-posix.c
index ab05b51a66..c8a0b109c2 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -2374,6 +2374,33 @@ static int coroutine_fn raw_co_create_opts(const char
*filename, QemuOpts *opts,
return raw_co_create(&options, errp);
}
+/**
+ * Co-routine function that erases a regular file.
+ */
+static int coroutine_fn raw_co_delete_file(const char *filename,
+ Error **errp)
+{
+ int ret;
+
+ /* Skip file: protocol prefix */
+ strstart(filename, "file:", &filename);
+
+ if (!bdrv_path_is_regular_file(filename)) {
+ ret = -ENOENT;
+ error_setg_errno(errp, -ret, "%s is not a regular file", filename);
+ goto done;
+ }
+
+ ret = unlink(filename);
+ if (ret < 0) {
+ ret = -errno;
+ error_setg_errno(errp, -ret, "Error when deleting file %s", filename);
+ }
+
+done:
+ return ret;
+}
+
/*
* Find allocation range in @bs around offset @start.
* May change underlying file descriptor's file offset.
@@ -2925,6 +2952,7 @@ BlockDriver bdrv_file = {
.bdrv_co_block_status = raw_co_block_status,
.bdrv_co_invalidate_cache = raw_co_invalidate_cache,
.bdrv_co_pwrite_zeroes = raw_co_pwrite_zeroes,
+ .bdrv_co_delete_file = raw_co_delete_file,
.bdrv_co_preadv = raw_co_preadv,
.bdrv_co_pwritev = raw_co_pwritev,
diff --git a/include/block/block.h b/include/block/block.h
index f9415ed740..d287eaa9a6 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -370,6 +370,7 @@ int bdrv_freeze_backing_chain(BlockDriverState *bs,
BlockDriverState *base,
Error **errp);
void bdrv_unfreeze_backing_chain(BlockDriverState *bs, BlockDriverState *base);
+bool bdrv_path_is_regular_file(const char *path);
typedef struct BdrvCheckResult {
int corruptions;
diff --git a/include/block/block_int.h b/include/block/block_int.h
index d6415b53c1..6d4135ff54 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -309,6 +309,12 @@ struct BlockDriver {
*/
int coroutine_fn (*bdrv_co_flush)(BlockDriverState *bs);
+ /*
+ * Delete a local created file.
+ */
+ int coroutine_fn (*bdrv_co_delete_file)(const char *filename,
+ Error **errp);
+
/*
* Flushes all data that was already written to the OS all the way down to
* the disk (for example file-posix.c calls fsync()).
--
2.20.1
