[PATCH] Don't pre-create read-only files with --extract --xattrs

[Pavel Raiskup]

We used to respect the target file mode when pre-creating files in
set_xattr, so we also pre-created read-only files that we were not able
to open later for writing.  This is now fixed, and we always create the
file with S_IWUSR.

Fixes the original bug report https://bugzilla.redhat.com/1886540

* src/extract.c (set_xattr): Blindly add S_IWUSR flag to pre-created
files, to avoid openat failures later.
---
 src/extract.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/extract.c b/src/extract.c
index b73a591..2e650ad 100644
--- a/src/extract.c
+++ b/src/extract.c
@@ -865,7 +865,13 @@ set_xattr (char const *file_name, struct tar_stat_info 
const *st,
 
       for (;;)
         {
-          if (!mknodat (chdir_fd, file_name, mode ^ invert_permissions, 0))
+          /* We'll open the file with O_WRONLY later by open_output_file,
+             therefore we need to give us the S_IWUSR bit.  If the file was
+             meant to be user-read-only, the permissions will be corrected by
+             the set_stat call. */
+          mode_t initial_mode = mode ^ invert_permissions | S_IWUSR;
+
+          if (!mknodat (chdir_fd, file_name, initial_mode, 0))
             {
               /* Successfully created file */
               xattrs_xattrs_set (st, file_name, typeflag, 0);
-- 
2.28.0