Besides being safe for arbitrary path lengths, after some follow-up
patches all callers will want a freshly allocated buffer anyway.
In the meantime, path_combine_deprecated() is added which has the same
interface as path_combine() had before this patch. All callers to that
function will be converted in follow-up patches.
Signed-off-by: Max Reitz <mre...@redhat.com>
---
block.c | 81 +++++++++++++++++++++++++++++----------------------
block/vmdk.c | 3 +-
include/block/block.h | 4 +--
3 files changed, 48 insertions(+), 40 deletions(-)
diff --git a/block.c b/block.c
index b3ff08f..41f3c92 100644
--- a/block.c
+++ b/block.c
@@ -146,48 +146,59 @@ int path_is_absolute(const char *path)
#endif
}
-/* if filename is absolute, just copy it to dest. Otherwise, build a
+/* if filename is absolute, just return its duplicate. Otherwise, build a
path to it by considering it is relative to base_path. URL are
supported. */
-void path_combine(char *dest, int dest_size,
- const char *base_path,
- const char *filename)
+char *path_combine(const char *base_path, const char *filename)
{
const char *p, *p1;
+ char *result;
int len;
- if (dest_size <= 0)
- return;
if (path_is_absolute(filename)) {
- pstrcpy(dest, dest_size, filename);
+ return g_strdup(filename);
+ }
+
+ p = strchr(base_path, ':');
+ if (p) {
+ p++;
} else {
- p = strchr(base_path, ':');
- if (p)
- p++;
- else
- p = base_path;
- p1 = strrchr(base_path, '/');
+ p = base_path;
+ }
+ p1 = strrchr(base_path, '/');
#ifdef _WIN32
- {
- const char *p2;
- p2 = strrchr(base_path, '\\');
- if (!p1 || p2 > p1)
- p1 = p2;
+ {
+ const char *p2;
+ p2 = strrchr(base_path, '\\');
+ if (!p1 || p2 > p1) {
+ p1 = p2;
}
+ }
#endif
- if (p1)
- p1++;
- else
- p1 = base_path;
- if (p1 > p)
- p = p1;
- len = p - base_path;
- if (len > dest_size - 1)
- len = dest_size - 1;
- memcpy(dest, base_path, len);
- dest[len] = '\0';
- pstrcat(dest, dest_size, filename);
+ if (p1) {
+ p1++;
+ } else {
+ p1 = base_path;
+ }
+ if (p1 > p) {
+ p = p1;
}
+ len = p - base_path;
+
+ result = g_malloc(len + strlen(filename) + 1);
+ memcpy(result, base_path, len);
+ strcpy(result + len, filename);
+
+ return result;
+}
+
+static void path_combine_deprecated(char *dest, int dest_size,
+ const char *base_path,
+ const char *filename)
+{
+ char *combined = path_combine(base_path, filename);
+ pstrcpy(dest, dest_size, combined);
+ g_free(combined);
}
void bdrv_get_full_backing_filename_from_filename(const char *backed,
@@ -203,7 +214,7 @@ void bdrv_get_full_backing_filename_from_filename(const
char *backed,
error_setg(errp, "Cannot use relative backing file names for '%s'",
backed);
} else {
- path_combine(dest, sz, backed, backing);
+ path_combine_deprecated(dest, sz, backed, backing);
}
}
@@ -3147,8 +3158,8 @@ BlockDriverState
*bdrv_find_backing_image(BlockDriverState *bs,
} else {
/* 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);
+ path_combine_deprecated(filename_tmp, PATH_MAX, curr_bs->filename,
+ backing_file);
/* We are going to compare absolute pathnames */
if (!realpath(filename_tmp, filename_full)) {
@@ -3157,8 +3168,8 @@ BlockDriverState
*bdrv_find_backing_image(BlockDriverState *bs,
/* 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);
+ path_combine_deprecated(filename_tmp, PATH_MAX, curr_bs->filename,
+ curr_bs->backing_file);
if (!realpath(filename_tmp, backing_file_full)) {
continue;
diff --git a/block/vmdk.c b/block/vmdk.c
index 45f9d3c..142de20 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -847,8 +847,7 @@ static int vmdk_parse_extents(const char *desc,
BlockDriverState *bs,
return -EINVAL;
}
- extent_path = g_malloc0(PATH_MAX);
- path_combine(extent_path, PATH_MAX, desc_file_path, fname);
+ extent_path = path_combine(desc_file_path, fname);
ret = snprintf(extent_opt_prefix, 32, "extents.%d", s->num_extents);
assert(ret < 32);
diff --git a/include/block/block.h b/include/block/block.h
index 3a73137..4604465 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -443,9 +443,7 @@ int bdrv_is_snapshot(BlockDriverState *bs);
int path_has_protocol(const char *path);
int path_is_absolute(const char *path);
-void path_combine(char *dest, int dest_size,
- const char *base_path,
- const char *filename);
+char *path_combine(const char *base_path, const char *filename);
int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
--
2.8.0
