[Qemu-devel] [PATCH 16/18] linux-user: Use safe_syscall wrapper for fcntl

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

Use the safe_syscall wrapper for fcntl. This is straightforward now
that we always use 'struct fcntl64' on the host, as we don't need
to select whether to call the host's fcntl64 or fcntl syscall
(a detail that the libc previously hid for us).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 linux-user/syscall.c | 34 +++++++++++++++++++++++-----------
 1 file changed, 23 insertions(+), 11 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index f3a487e..249d246 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -764,6 +764,16 @@ safe_syscall5(int, mq_timedreceive, int, mqdes, char *, msg_ptr,
  * the libc function.
  */
 #define safe_ioctl(...) safe_syscall(__NR_ioctl, __VA_ARGS__)
+/* Similarly for fcntl. Note that callers must always:
+ *  pass the F_GETLK64 etc constants rather than the unsuffixed F_GETLK
+ *  use the flock64 struct rather than unsuffixed flock
+ * This will then work and use a 64-bit offset for both 32-bit and 64-bit hosts.
+ */
+#ifdef __NR_fcntl64
+#define safe_fcntl(...) safe_syscall(__NR_fcntl64, __VA_ARGS__)
+#else
+#define safe_fcntl(...) safe_syscall(__NR_fcntl, __VA_ARGS__)
+#endif
 
 static inline int host_to_target_sock_type(int host_type)
 {
@@ -5092,7 +5102,7 @@ static abi_long do_fcntl(int fd, int cmd, abi_ulong arg)
         if (copy_from_user_flock(&fl64, arg)) {
             return -TARGET_EFAULT;
         }
-        ret = get_errno(fcntl(fd, host_cmd, &fl64));
+        ret = get_errno(safe_fcntl(fd, host_cmd, &fl64));
         if (ret == 0) {
             if (copy_to_user_flock(arg, &fl64)) {
                 return -TARGET_EFAULT;
@@ -5105,14 +5115,14 @@ static abi_long do_fcntl(int fd, int cmd, abi_ulong arg)
         if (copy_from_user_flock(&fl64, arg)) {
             return -TARGET_EFAULT;
         }
-        ret = get_errno(fcntl(fd, host_cmd, &fl64));
+        ret = get_errno(safe_fcntl(fd, host_cmd, &fl64));
         break;
 
     case TARGET_F_GETLK64:
         if (copy_from_user_flock64(&fl64, arg)) {
             return -TARGET_EFAULT;
         }
-        ret = get_errno(fcntl(fd, host_cmd, &fl64));
+        ret = get_errno(safe_fcntl(fd, host_cmd, &fl64));
         if (ret == 0) {
             if (copy_to_user_flock64(arg, &fl64)) {
                 return -TARGET_EFAULT;
@@ -5124,23 +5134,25 @@ static abi_long do_fcntl(int fd, int cmd, abi_ulong arg)
         if (copy_from_user_flock64(&fl64, arg)) {
             return -TARGET_EFAULT;
         }
-        ret = get_errno(fcntl(fd, host_cmd, &fl64));
+        ret = get_errno(safe_fcntl(fd, host_cmd, &fl64));
         break;
 
     case TARGET_F_GETFL:
-        ret = get_errno(fcntl(fd, host_cmd, arg));
+        ret = get_errno(safe_fcntl(fd, host_cmd, arg));
         if (ret >= 0) {
             ret = host_to_target_bitmask(ret, fcntl_flags_tbl);
         }
         break;
 
     case TARGET_F_SETFL:
-        ret = get_errno(fcntl(fd, host_cmd, target_to_host_bitmask(arg, fcntl_flags_tbl)));
+        ret = get_errno(safe_fcntl(fd, host_cmd,
+                                   target_to_host_bitmask(arg,
+                                                          fcntl_flags_tbl)));
         break;
 
 #ifdef F_GETOWN_EX
     case TARGET_F_GETOWN_EX:
-        ret = get_errno(fcntl(fd, host_cmd, &fox));
+        ret = get_errno(safe_fcntl(fd, host_cmd, &fox));
         if (ret >= 0) {
             if (!lock_user_struct(VERIFY_WRITE, target_fox, arg, 0))
                 return -TARGET_EFAULT;
@@ -5158,7 +5170,7 @@ static abi_long do_fcntl(int fd, int cmd, abi_ulong arg)
         fox.type = tswap32(target_fox->type);
         fox.pid = tswap32(target_fox->pid);
         unlock_user_struct(target_fox, arg, 0);
-        ret = get_errno(fcntl(fd, host_cmd, &fox));
+        ret = get_errno(safe_fcntl(fd, host_cmd, &fox));
         break;
 #endif
 
@@ -5168,11 +5180,11 @@ static abi_long do_fcntl(int fd, int cmd, abi_ulong arg)
     case TARGET_F_GETSIG:
     case TARGET_F_SETLEASE:
     case TARGET_F_GETLEASE:
-        ret = get_errno(fcntl(fd, host_cmd, arg));
+        ret = get_errno(safe_fcntl(fd, host_cmd, arg));
         break;
 
     default:
-        ret = get_errno(fcntl(fd, cmd, arg));
+        ret = get_errno(safe_fcntl(fd, cmd, arg));
         break;
     }
     return ret;
@@ -9605,7 +9617,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
             if (copyfrom(&fl, arg3)) {
                 goto efault;
             }
-            ret = get_errno(fcntl(arg1, cmd, &fl));
+            ret = get_errno(safe_fcntl(arg1, cmd, &fl));
 	    break;
         default:
             ret = do_fcntl(arg1, arg2, arg3);
-- 
1.9.1