[Qemu-devel] [PATCH 07/10] linux-user: fix utimensat when used as futimens

[riku . voipio]

From: Riku Voipio <address@hidden>

The glibc function for utimensat glibc returns -EINVAL when the path is null
which is a different behaviour with the syscall.

path can be null because internally the glibc is using utimensat with
path null when implmenting futimens. If path is null, call futimes
instead.

Also, add a check for utimensat at configure time.

Signed-off-by: Riku Voipio <address@hidden>
---
 configure            |   22 ++++++++++++++++++++++
 linux-user/syscall.c |   23 ++++++++++++++---------
 2 files changed, 36 insertions(+), 9 deletions(-)

diff --git a/configure b/configure
index bc89227..c45bd75 100755
--- a/configure
+++ b/configure
@@ -1241,6 +1241,25 @@ EOF
   fi
 fi
 
+# check if utimensat and futimens are supported
+utimens=no
+cat > $TMPC << EOF
+#define _ATFILE_SOURCE
+#define _GNU_SOURCE
+#include <stddef.h>
+#include <fcntl.h>
+
+int main(void)
+{
+    utimensat(AT_FDCWD, "foo", NULL, 0);
+    futimens(0, NULL);
+    return 0;
+}
+EOF
+if $cc $ARCH_CFLAGS -o $TMPE $TMPC 2> /dev/null ; then
+  utimens=yes
+fi
+
 # Check if tools are available to build documentation.
 if [ -x "`which texi2html 2>/dev/null`" ] && \
    [ -x "`which pod2man 2>/dev/null`" ]; then
@@ -1640,6 +1659,9 @@ fi
 if test "$atfile" = "yes" ; then
   echo "#define CONFIG_ATFILE 1" >> $config_h
 fi
+if test "$utimens" = "yes" ; then
+  echo "#define CONFIG_UTIMENSAT 1" >> $config_h
+fi
 if test "$inotify" = "yes" ; then
   echo "#define CONFIG_INOTIFY 1" >> $config_h
 fi
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index f1d844f..b76d6aa 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -406,13 +406,6 @@ static int sys_unlinkat(int dirfd, const char *pathname, 
int flags)
   return (unlinkat(dirfd, pathname, flags));
 }
 #endif
-#ifdef TARGET_NR_utimensat
-static int sys_utimensat(int dirfd, const char *pathname,
-    const struct timespec times[2], int flags)
-{
-  return (utimensat(dirfd, pathname, times, flags));
-}
-#endif
 #else /* !CONFIG_ATFILE */
 
 /*
@@ -471,12 +464,24 @@ _syscall3(int,sys_symlinkat,const char *,oldpath,
 #if defined(TARGET_NR_unlinkat) && defined(__NR_unlinkat)
 _syscall3(int,sys_unlinkat,int,dirfd,const char *,pathname,int,flags)
 #endif
+
+#endif /* CONFIG_ATFILE */
+
+#ifdef CONFIG_UTIMENSAT
+static int sys_utimensat(int dirfd, const char *pathname,
+    const struct timespec times[2], int flags)
+{
+    if (pathname == NULL)
+        return futimens(dirfd, times);
+    else
+        return utimensat(dirfd, pathname, times, flags);
+}
+#else
 #if defined(TARGET_NR_utimensat) && defined(__NR_utimensat)
 _syscall4(int,sys_utimensat,int,dirfd,const char *,pathname,
           const struct timespec *,tsp,int,flags)
 #endif
-
-#endif /* CONFIG_ATFILE */
+#endif /* CONFIG_UTIMENSAT  */
 
 #ifdef CONFIG_INOTIFY
 #include <sys/inotify.h>
-- 
1.6.2.1