[Qemu-devel] [PATCH v5 06/25] block: bdrv_get_full_backing_filename_from_...'s ret. val.

From: Max Reitz <mreitz@redhat.com>
To: qemu-block@nongnu.org
Cc: qemu-devel@nongnu.org, Max Reitz <mreitz@redhat.com>,
	Kevin Wolf <kwolf@redhat.com>, Alberto Garcia <berto@igalia.com>,
	Eric Blake <eblake@redhat.com>
Subject: [Qemu-devel] [PATCH v5 06/25] block: bdrv_get_full_backing_filename_from_...'s ret. val.
Date: Wed, 21 Jun 2017 14:50:28 +0200	[thread overview]
Message-ID: <20170621125047.30294-7-mreitz@redhat.com> (raw)
In-Reply-To: <20170621125047.30294-1-mreitz@redhat.com>

Make bdrv_get_full_backing_filename_from_filename() return an allocated
string instead of placing the result in a caller-provided buffer.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
---
 include/block/block.h |  7 +++----
 block.c               | 32 +++++++++++++++++++-------------
 block/vmdk.c          |  8 +++-----
 3 files changed, 25 insertions(+), 22 deletions(-)

diff --git a/include/block/block.h b/include/block/block.h
index 9f89fa7..e9df983 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -494,10 +494,9 @@ void bdrv_get_backing_filename(BlockDriverState *bs,
                                char *filename, int filename_size);
 void bdrv_get_full_backing_filename(BlockDriverState *bs,
                                     char *dest, size_t sz, Error **errp);
-void bdrv_get_full_backing_filename_from_filename(const char *backed,
-                                                  const char *backing,
-                                                  char *dest, size_t sz,
-                                                  Error **errp);
+char *bdrv_get_full_backing_filename_from_filename(const char *backed,
+                                                   const char *backing,
+                                                   Error **errp);
 
 int path_has_protocol(const char *path);
 int path_is_absolute(const char *path);
diff --git a/block.c b/block.c
index 80e4805..b70a9a8 100644
--- a/block.c
+++ b/block.c
@@ -287,20 +287,20 @@ int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp)
     return 0;
 }
 
-void bdrv_get_full_backing_filename_from_filename(const char *backed,
-                                                  const char *backing,
-                                                  char *dest, size_t sz,
-                                                  Error **errp)
+char *bdrv_get_full_backing_filename_from_filename(const char *backed,
+                                                   const char *backing,
+                                                   Error **errp)
 {
     if (backing[0] == '\0' || path_has_protocol(backing) ||
         path_is_absolute(backing))
     {
-        pstrcpy(dest, sz, backing);
+        return g_strdup(backing);
     } else if (backed[0] == '\0' || strstart(backed, "json:", NULL)) {
         error_setg(errp, "Cannot use relative backing file names for '%s'",
                    backed);
+        return NULL;
     } else {
-        path_combine_deprecated(dest, sz, backed, backing);
+        return path_combine(backed, backing);
     }
 }
 
@@ -308,9 +308,15 @@ void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz,
                                     Error **errp)
 {
     char *backed = bs->exact_filename[0] ? bs->exact_filename : bs->filename;
+    char *full_name;
 
-    bdrv_get_full_backing_filename_from_filename(backed, bs->backing_file,
-                                                 dest, sz, errp);
+    full_name = bdrv_get_full_backing_filename_from_filename(backed,
+                                                             bs->backing_file,
+                                                             errp);
+    if (full_name) {
+        pstrcpy(dest, sz, full_name);
+        g_free(full_name);
+    }
 }
 
 void bdrv_register(BlockDriver *bdrv)
@@ -4431,16 +4437,16 @@ void bdrv_img_create(const char *filename, const char *fmt,
     if (size == -1) {
         if (backing_file) {
             BlockDriverState *bs;
-            char *full_backing = g_new0(char, PATH_MAX);
+            char *full_backing;
             int64_t size;
             int back_flags;
             QDict *backing_options = NULL;
 
-            bdrv_get_full_backing_filename_from_filename(filename, backing_file,
-                                                         full_backing, PATH_MAX,
-                                                         &local_err);
+            full_backing =
+                bdrv_get_full_backing_filename_from_filename(filename,
+                                                             backing_file,
+                                                             &local_err);
             if (local_err) {
-                g_free(full_backing);
                 goto out;
             }
 
diff --git a/block/vmdk.c b/block/vmdk.c
index 4389a69..4e92ce4 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -1983,12 +1983,10 @@ static int vmdk_create(const char *filename, QemuOpts *opts, Error **errp)
     }
     if (backing_file) {
         BlockBackend *blk;
-        char *full_backing = g_new0(char, PATH_MAX);
-        bdrv_get_full_backing_filename_from_filename(filename, backing_file,
-                                                     full_backing, PATH_MAX,
-                                                     &local_err);
+        char *full_backing =
+            bdrv_get_full_backing_filename_from_filename(filename, backing_file,
+                                                         &local_err);
         if (local_err) {
-            g_free(full_backing);
             error_propagate(errp, local_err);
             ret = -ENOENT;
             goto exit;
-- 
2.9.4
