On 2025-05-02 at 23:33:32, Collin Funk wrote:
> As documented on NetBSD's man page, open with the O_NOFOLLOW flag and a
> symlink returns -1 and sets errno to EFTYPE which differs from POSIX.
> This patch fixes the following test failure:
>
> $ sh t0602-reffiles-fsck.sh --verbose
> --- expect 2025-05-02 23:05:23.920890147 +0000
> +++ err 2025-05-02 23:05:23.916794959 +0000
> @@ -1 +1 @@
> -error: packed-refs: badRefFiletype: not a regular file but a symlink
> +error: unable to open '.git/packed-refs': Inappropriate file type or format
> not ok 12 - the filetype of packed-refs should be checked
>
> This portability issue was introduced in Commit
> cfea2f2da8 (packed-backend: check whether the "packed-refs" is regular file, 2025-02-28)
>
> Signed-off-by: Collin Funk <collin.funk1@xxxxxxxxx>
> ---
> wrapper.c | 14 +++++++++++++-
> 1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/wrapper.c b/wrapper.c
> index 3c79778055..4d448d7c57 100644
> --- a/wrapper.c
> +++ b/wrapper.c
> @@ -737,7 +737,19 @@ int is_empty_or_missing_file(const char *filename)
> int open_nofollow(const char *path, int flags)
> {
> #ifdef O_NOFOLLOW
> - return open(path, flags | O_NOFOLLOW);
> + int ret = open(path, flags | O_NOFOLLOW);
> +#ifdef __NetBSD__
> + /*
> + * NetBSD sets errno to EFTYPE when path is a symlink. The only other
> + * time this errno occurs when O_REGULAR is used. Since we don't use
> + * it anywhere we can avoid an lstat here.
> + */
> + if (ret < 0 && errno == EFTYPE) {
> + errno = ELOOP;
> + return -1;
> + }
> +#endif
> + return ret;
This patch seems reasonable and correct. I don't use NetBSD, but I do
often test there, and I'm aware of this infelicity. I'm surprised we
haven't hit it before.
I suspect we'll also hit this on FreeBSD, which has a similar issue in
that it returns `EMLINK` instead of `ELOOP`. I do wish these two OSes
would provide an appropriate POSIX-compatible `open` call when set with
`_POSIX_SOURCE`, since this is one of the biggest portability problems
with them.
--
brian m. carlson (they/them)
Toronto, Ontario, CA
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