libarchive/get_header_ar.c: fix extraction of archives from binutils in deterministic mode

GNU binutils in deterministic mode (ar rD or built with
--enable-deterministic-archives) hard codes file mode to 0644 (NOT 0100644)
since https://github.com/bminor/binutils-gdb/commit/36e4dce69dd2

This confuses busybox ar x (data_extract_all):

touch a; ar rD a.ar a
ar: creating a.ar

busybox ar x a.ar
ar: unrecognized file type
hexdump -C a.ar
00000000  21 3c 61 72 63 68 3e 0a  61 2f 20 20 20 20 20 20  |!<arch>.a/      |
00000010  20 20 20 20 20 20 20 20  30 20 20 20 20 20 20 20  |        0       |
00000020  20 20 20 20 30 20 20 20  20 20 30 20 20 20 20 20  |    0     0     |
00000030  36 34 34 20 20 20 20 20  30 20 20 20 20 20 20 20  |644     0       |
00000040  20 20 60 0a                                       |  `.|

As a workaround, force the mode bits to S_IFREG, as nothing else makes sense
for ar.

function                                             old     new   delta
get_header_ar                                        539     542      +3

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/archival/libarchive/get_header_ar.c b/archival/libarchive/get_header_ar.c
index 3a19d6ff7..6bd897392 100644
--- a/archival/libarchive/get_header_ar.c
+++ b/archival/libarchive/get_header_ar.c
@@ -92,8 +92,12 @@ char FAST_FUNC get_header_ar(archive_handle_t *archive_handle)
         /* Only size is always present, the rest may be missing in
          * long filename pseudo file. Thus we decode the rest
          * after dealing with long filename pseudo file.
+         *
+         * GNU binutils in deterministic mode hard codes mode to 0644 (NOT
+         * 0100644). AR archives can only contain files, so force file
+         * mode.
          */
-        typed->mode = read_num(ar.formatted.mode, 8, sizeof(ar.formatted.mode));
+        typed->mode = read_num(ar.formatted.mode, 8, sizeof(ar.formatted.mode)) | S_IFREG;
         typed->gid = read_num(ar.formatted.gid, 10, sizeof(ar.formatted.gid));
         typed->uid = read_num(ar.formatted.uid, 10, sizeof(ar.formatted.uid));
         typed->mtime = read_num(ar.formatted.date, 10, sizeof(ar.formatted.date));