From 3f4fcb62661059bad77a2e957b4621137797bc2f Mon Sep 17 00:00:00 2001
From: Rui Wang <rui.wang@windriver.com>
Date: Fri, 15 Jun 2018 14:19:10 +0800
Subject: [PATCH] attr: fix utime for symlink

unfs3 has an old defect that it can not change the timestamps of a
symlink file because it only uses utime(), which will follow the
symlink. This will not cause an error if the symlink points to an
existent file. But under some special situation, such as installing
a rpm package, rpm tool will create the symlink first and try to
modify the timestamps of it, when the target file is non-existent.
This will cause an ESTALE error. Making rpm tool ignore this error
is a solution, but not the best one. An acceptable approach is
Making unfs3 support lutimes(), which can modify the symlink file
itself. Considering not every system support this function, so a
function checking is necessary.

Upstream-Status: Submitted [https://sourceforge.net/p/unfs3/bugs/12/]

Signed-off-by: Rui Wang <rui.wang@windriver.com>
---
 attr.c         | 15 +++++++++++----
 backend_unix.h |  2 ++
 configure.ac   |  1 +
 3 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/attr.c b/attr.c
index 73e5c75..427d0e2 100644
--- a/attr.c
+++ b/attr.c
@@ -280,7 +280,7 @@ post_op_attr get_post_cached(struct svc_req * req)
 static nfsstat3 set_time(const char *path, backend_statstruct buf, sattr3 new)
 {
     time_t new_atime, new_mtime;
-    struct utimbuf utim;
+    struct timeval stamps[2];
     int res;

     /* set atime and mtime */
@@ -302,10 +302,17 @@ static nfsstat3 set_time(const char *path, backend_statstruct buf, sattr3 new)
	else			       /* DONT_CHANGE */
	    new_mtime = buf.st_mtime;

-	utim.actime = new_atime;
-	utim.modtime = new_mtime;
+	stamps[0].tv_sec = new_atime;
+	stamps[0].tv_usec = 0;
+	stamps[1].tv_sec = new_mtime;
+	stamps[1].tv_usec = 0;
+
+#if HAVE_LUTIMES
+	res = backend_lutimes(path, stamps);
+#else
+	res = backend_utimes(path, stamps);
+#endif

-	res = backend_utime(path, &utim);
	if (res == -1)
	    return setattr_err();
     }
diff --git a/backend_unix.h b/backend_unix.h
index fbc2af3..813ffd3 100644
--- a/backend_unix.h
+++ b/backend_unix.h
@@ -61,6 +61,8 @@
 #define backend_symlink symlink
 #define backend_truncate truncate
 #define backend_utime utime
+#define backend_utimes utimes
+#define backend_lutimes lutimes
 #define backend_statstruct struct stat
 #define backend_dirstream DIR
 #define backend_statvfsstruct struct statvfs
diff --git a/configure.ac b/configure.ac
index aeec598..ea7f167 100644
--- a/configure.ac
+++ b/configure.ac
@@ -37,6 +37,7 @@ AC_CHECK_FUNCS(setresuid setresgid)
 AC_CHECK_FUNCS(vsyslog)
 AC_CHECK_FUNCS(lchown)
 AC_CHECK_FUNCS(setgroups)
+AC_CHECK_FUNCS(lutimes)
 UNFS3_SOLARIS_RPC
 UNFS3_PORTMAP_DEFINE
 UNFS3_COMPILE_WARNINGS