Thanks for reporting that. I installed the attached patch which I hopes
fixes it, and am boldly closing the bug report.From d636f9c117d6383fedcc769661fa0fa4d372b153 Mon Sep 17 00:00:00 2001
From: Paul Eggert <egg...@cs.ucla.edu>
Date: Tue, 11 Jun 2024 17:48:14 -0700
Subject: [PATCH] diff: port to FreeBSD, NetBSD
Problem reported by Bruno Haible <https://bugs.gnu.org/71486>.
* src/diff.c (NOFOLLOW_SYMLINK_ERRNO): New constant.
(compare_files): Use it instead of ELOOP. When it is not ELOOP,
treat ELOOP as a failure in resolving the parent directory;
this saves a syscall in some situation.
---
src/diff.c | 31 +++++++++++++++++++++++++------
1 file changed, 25 insertions(+), 6 deletions(-)
diff --git a/src/diff.c b/src/diff.c
index 76432ee..3abcb66 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -1139,6 +1139,20 @@ dir_p (struct comparison const *pcmp, int f)
return S_ISDIR (pcmp->file[f].stat.st_mode) != 0;
}
+/* If openat with O_NOFOLLOW fails because the file is a symlink,
+ this platform sets errno to NOFOLLOW_SYMLINK_ERRNO.
+ Although POSIX says errno must be ELOOP in that situation,
+ FreeBSD and NetBSD behave more usefully. */
+enum { NOFOLLOW_SYMLINK_ERRNO =
+#ifdef __FreeBSD__
+ EMLINK
+#elif defined __NetBSD__
+ EFTYPE
+#else
+ ELOOP
+#endif
+};
+
/* Compare two files with parent comparison PARENT.
The two files are described by CMP, which has been prepped to contain
the files' stat results, file types, and possibly descriptors.
@@ -1485,10 +1499,14 @@ compare_files (struct comparison const *parent, enum detype const detype[2],
err = 0;
}
- /* If it might be a symlink, play it safe and fstatat later. */
- if (err == ELOOP && no_dereference_symlinks
- && (detype[f] == DE_UNKNOWN
- || (detype[f] == DE_LNK && accmode == O_RDONLY)))
+ /* If it is a symlink, fstatat later. If it might be a
+ symlink, play it safe and fstatat later. */
+ if (err == NOFOLLOW_SYMLINK_ERRNO
+ && (NOFOLLOW_SYMLINK_ERRNO != ELOOP
+ || (no_dereference_symlinks
+ && (detype[f] == DE_UNKNOWN
+ || (detype[f] == DE_LNK
+ && accmode == O_RDONLY)))))
{
fd = UNOPENED;
err = 0;
@@ -1561,11 +1579,12 @@ compare_files (struct comparison const *parent, enum detype const detype[2],
: openat (dirfd, atname, O_RDONLY | oflags));
if (O_PATH_DEFINED && cmp.file[dir_arg].desc < 0
&& (dir_detype == DE_LNK || dir_detype == DE_UNKNOWN)
- && no_dereference_symlinks && errno == ELOOP)
+ && no_dereference_symlinks && errno == NOFOLLOW_SYMLINK_ERRNO)
cmp.file[dir_arg].desc = openat (dirfd, atname,
O_PATHSEARCH | oflags);
if (cmp.file[dir_arg].desc < 0
- ? (O_PATH_DEFINED || !no_dereference_symlinks || errno != ELOOP
+ ? (O_PATH_DEFINED || !no_dereference_symlinks
+ || errno != NOFOLLOW_SYMLINK_ERRNO
|| (fstatat (dirfd, atname, &cmp.file[dir_arg].stat,
AT_SYMLINK_NOFOLLOW)
< 0))
--
2.45.2
