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[05/12] linux-user: Conditionally Pass Attribute Pointer to mq_open()

Message ID 1407170739-12237-6-git-send-email-tommusta@gmail.com
State New
Headers show

Commit Message

Tom Musta Aug. 4, 2014, 4:45 p.m. UTC
The mq_open system call takes an optional struct mq_attr pointer
argument in the fourth position.  This pointer is used when O_CREAT
is specified in the flags (second) argument.  It may be NULL, in
which case the queue is created with implementation defined attributes.

Change the code to properly handle the case when NULL is passed in the
arg4 position.

Signed-off-by: Tom Musta <tommusta@gmail.com>

Comments

Peter Maydell Aug. 4, 2014, 5:10 p.m. UTC | #1
On 4 August 2014 17:45, Tom Musta <tommusta@gmail.com> wrote:
> The mq_open system call takes an optional struct mq_attr pointer
> argument in the fourth position.  This pointer is used when O_CREAT
> is specified in the flags (second) argument.  It may be NULL, in
> which case the queue is created with implementation defined attributes.
>
> Change the code to properly handle the case when NULL is passed in the
> arg4 position.
>
> Signed-off-by: Tom Musta <tommusta@gmail.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM
diff mbox

Patch

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index bf6dd1e..c0c0434 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -9078,12 +9078,16 @@  abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
 #if defined(TARGET_NR_mq_open) && defined(__NR_mq_open)
     case TARGET_NR_mq_open:
         {
-            struct mq_attr posix_mq_attr;
+            struct mq_attr posix_mq_attr, *attrp;
 
             p = lock_user_string(arg1 - 1);
-            if (arg4 != 0)
+            if (arg4 != 0) {
                 copy_from_user_mq_attr (&posix_mq_attr, arg4);
-            ret = get_errno(mq_open(p, arg2, arg3, &posix_mq_attr));
+                attrp = &posix_mq_attr;
+            } else {
+                attrp = 0;
+            }
+            ret = get_errno(mq_open(p, arg2, arg3, attrp));
             unlock_user (p, arg1, 0);
         }
         break;