[Qemu-devel] [PATCH] linux-user: Fix sys_utimensat (would not compile on old glibc)

[Peter Maydell <peter.maydell@linaro.org>]

Commit c0d472b12e accidentally dropped the definition of
__NR_SYS_utimensat even though its use is guarded by
CONFIG_UTIMENSAT, not CONFIG_ATFILE. Some older glibc don't
have utimensat() (even if they have the other *at() functions).
Fix this by correctly cleaning up the sys_utimensat()
implementation and #defines, so that we always provide the
syscall if needed whether we're doing it via glibc or not.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 linux-user/syscall.c |   16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index cdd0c28..f7877c3 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -338,6 +338,7 @@ static int sys_openat(int dirfd, const char *pathname, int flags, mode_t mode)
 }
 #endif
 
+#ifdef TARGET_NR_utimensat
 #ifdef CONFIG_UTIMENSAT
 static int sys_utimensat(int dirfd, const char *pathname,
     const struct timespec times[2], int flags)
@@ -347,12 +348,19 @@ static int sys_utimensat(int dirfd, const char *pathname,
     else
         return utimensat(dirfd, pathname, times, flags);
 }
-#else
-#if defined(TARGET_NR_utimensat) && defined(__NR_utimensat)
+#elif defined(__NR_utimensat)
+#define __NR_sys_utimensat __NR_utimensat
 _syscall4(int,sys_utimensat,int,dirfd,const char *,pathname,
           const struct timespec *,tsp,int,flags)
+#else
+static int sys_utimensat(int dirfd, const char *pathname,
+                         const struct timespec times[2], int flags)
+{
+    errno = ENOSYS;
+    return -1;
+}
 #endif
-#endif /* CONFIG_UTIMENSAT  */
+#endif /* TARGET_NR_utimensat */
 
 #ifdef CONFIG_INOTIFY
 #include <sys/inotify.h>
@@ -8536,7 +8544,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
         goto unimplemented_nowarn;
 #endif
 
-#if defined(TARGET_NR_utimensat) && defined(__NR_utimensat)
+#if defined(TARGET_NR_utimensat)
     case TARGET_NR_utimensat:
         {
             struct timespec *tsp, ts[2];
-- 
1.7.9.5