[PATCH v2] btrfs-progs: fix bug on mkfs with relative path specified

[Gui Hecheng]

The bug accurs when exec:
        # mkfs.btrfs -r <a relative path> <device>
        (note: the path should be 'valid' correspond to your `pwd`)
error msg:
        $ scandir for <a relative path> failed: No such file...

o Replace strdup() with realpath() to get the correct scan path.
o fix memory leaks and adopt the "single return + goto out" pattern

Reported-by: Saul Wold <s...@linux.intel.com>
Signed-off-by: Gui Hecheng <guihc.f...@cn.fujitsu.com>
---
change log
        v1->v2: 1. add check for realpath() return value
                2. fix memory leaks for dir_entry
                3. adopt "single return + goto out" pattern
---
 mkfs.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/mkfs.c b/mkfs.c
index 2dc90c2..d7049c9 100644
--- a/mkfs.c
+++ b/mkfs.c
@@ -756,6 +756,7 @@ static int traverse_directory(struct btrfs_trans_handle 
*trans,
        ino_t parent_inum, cur_inum;
        ino_t highest_inum = 0;
        char *parent_dir_name;
+       char real_path[PATH_MAX];
        struct btrfs_path path;
        struct extent_buffer *leaf;
        struct btrfs_key root_dir_key;
@@ -764,7 +765,12 @@ static int traverse_directory(struct btrfs_trans_handle 
*trans,
        /* Add list for source directory */
        dir_entry = malloc(sizeof(struct directory_name_entry));
        dir_entry->dir_name = dir_name;
-       dir_entry->path = strdup(dir_name);
+       dir_entry->path = realpath(dir_name, real_path);
+       if (!dir_entry->path) {
+               fprintf(stderr, "get directory real path error\n");
+               ret = -1;
+               goto fail_no_dir;
+       }
 
        parent_inum = highest_inum + BTRFS_FIRST_FREE_OBJECTID;
        dir_entry->inum = parent_inum;
@@ -778,7 +784,7 @@ static int traverse_directory(struct btrfs_trans_handle 
*trans,
        ret = btrfs_lookup_inode(trans, root, &path, &root_dir_key, 1);
        if (ret) {
                fprintf(stderr, "root dir lookup error\n");
-               return -1;
+               goto fail_no_dir;
        }
 
        leaf = path.nodes[0];
@@ -802,6 +808,7 @@ static int traverse_directory(struct btrfs_trans_handle 
*trans,
                if (chdir(parent_dir_entry->path)) {
                        fprintf(stderr, "chdir error for %s\n",
                                parent_dir_name);
+                       ret = -1;
                        goto fail_no_files;
                }
 
@@ -811,6 +818,7 @@ static int traverse_directory(struct btrfs_trans_handle 
*trans,
                {
                        fprintf(stderr, "scandir for %s failed: %s\n",
                                parent_dir_name, strerror (errno));
+                       ret = -1;
                        goto fail;
                }
 
@@ -820,6 +828,7 @@ static int traverse_directory(struct btrfs_trans_handle 
*trans,
                        if (lstat(cur_file->d_name, &st) == -1) {
                                fprintf(stderr, "lstat failed for file %s\n",
                                        cur_file->d_name);
+                               ret = -1;
                                goto fail;
                        }
 
@@ -876,20 +885,22 @@ static int traverse_directory(struct btrfs_trans_handle 
*trans,
                }
 
                free_namelist(files, count);
-               free(parent_dir_entry->path);
                free(parent_dir_entry);
 
                index_cnt = 2;
 
        } while (!list_empty(&dir_head->list));
 
-       return 0;
+out:
+       return !!ret;
 fail:
        free_namelist(files, count);
 fail_no_files:
-       free(parent_dir_entry->path);
        free(parent_dir_entry);
-       return -1;
+       goto out;
+fail_no_dir:
+       free(dir_entry);
+       goto out;
 }
 
 static int open_target(char *output_name)
-- 
1.8.1.4

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