[Qemu-devel] [PATCH 07/21] linux-user: fix utimensat

[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.

don't try to copy timespec from user if is NULL.

Add configure check for older systems

Signed-off-by: Riku Voipio <address@hidden>
---
 configure            |   22 ++++++++++++++++++++++
 linux-user/syscall.c |   38 ++++++++++++++++++++++++--------------
 2 files changed, 46 insertions(+), 14 deletions(-)

diff --git a/configure b/configure
index 11501c6..ecea67c 100755
--- a/configure
+++ b/configure
@@ -1281,6 +1281,25 @@ 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 $TMPC 2> /dev/null ; then
+  utimens=yes
+fi
+
 # Check if tools are available to build documentation.
 if test "$build_docs" = "yes" -a \( ! -x "`which texi2html 2>/dev/null`" -o ! 
-x "`which pod2man 2>/dev/null`" \) ; then
   build_docs="no"
@@ -1679,6 +1698,9 @@ 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 056581d..9e4e061 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>
@@ -6669,17 +6674,22 @@ abi_long do_syscall(void *cpu_env, int num, abi_long 
arg1,
 #if defined(TARGET_NR_utimensat) && defined(__NR_utimensat)
     case TARGET_NR_utimensat:
         {
-            struct timespec ts[2];
-            target_to_host_timespec(ts, arg3);
-            target_to_host_timespec(ts+1, arg3+sizeof(struct target_timespec));
+            struct timespec *tsp, ts[2];
+            if (!arg3) {
+                tsp = NULL;
+            } else {
+                target_to_host_timespec(ts, arg3);
+                target_to_host_timespec(ts+1, arg3+sizeof(struct 
target_timespec));
+                tsp = ts;
+            }
             if (!arg2)
-                ret = get_errno(sys_utimensat(arg1, NULL, ts, arg4));
+                ret = get_errno(sys_utimensat(arg1, NULL, tsp, arg4));
             else {
                 if (!(p = lock_user_string(arg2))) {
                     ret = -TARGET_EFAULT;
                     goto fail;
                 }
-                ret = get_errno(sys_utimensat(arg1, path(p), ts, arg4));
+                ret = get_errno(sys_utimensat(arg1, path(p), tsp, arg4));
                 unlock_user(p, arg2, 0);
             }
         }
-- 
1.6.2.1