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Re: [patch] fix tkill_failed gcc warning in gdbserver
On Mon, Dec 21, 2009 at 12:36 PM, Doug Evans <dje@google.com> wrote:
> On Mon, Dec 21, 2009 at 12:19 PM, Daniel Jacobowitz <drow@false.org> wrote:
>> On Mon, Dec 21, 2009 at 12:10:33PM -0800, Doug Evans wrote:
>>> Hi.
>>>
>>> android doesn't have SYS_tkill but it does have __NR_tkill.
>>
>> Does it have the other SYS_ constants? ?It's a weird omission.
>> Anyway, might as well use __NR_tkill unconditionally.
>
> The next question is, does gdbserver need to check for
> syscall.h/syscall() like gdb does?
> Or can I just replace #ifdef SYS_tkill with #ifdef __NR_tkill.
> gdbserver includes sys/syscall.h unconditionally, gdb/linux-nat.c ?does not.
> gdb also checks for __NR_tkill in a way that works if it were an enum.
> Does one need to worry about that case?
>
How about this?
2009-12-21 Doug Evans <dje@google.com>
gdb/
* linux-nat.c (kill_lwp): Minor cleanup, move definition of
tkill_failed into ifdef HAVE_TKILL_SYSCALL. Move setting of errno
there too. Delete unnecessary resetting of errno after syscall.
Minor comment changes to match gdbserver/linux-low.c:kill_lwp.
gdbserver/
* linux-low.c (kill_lwp): Use __NR_tkill instead of SYS_tkill.
Move definition of tkill_failed to ifdef __NR_tkill to avoid gcc
warning ifndef __NR_tkill. Move setting of errno there too.
Delete unnecessary resetting of errno after syscall.
Minor comment changes to match gdb/linux-nat.c:kill_lwp.
Index: linux-nat.c
===================================================================
RCS file: /cvs/src/src/gdb/linux-nat.c,v
retrieving revision 1.156
diff -u -p -r1.156 linux-nat.c
--- linux-nat.c 20 Nov 2009 19:48:45 -0000 1.156
+++ linux-nat.c 21 Dec 2009 20:39:15 -0000
@@ -2034,27 +2034,29 @@ linux_nat_resume (struct target_ops *ops
target_async (inferior_event_handler, 0);
}
-/* Issue kill to specified lwp. */
-
-static int tkill_failed;
+/* Send a signal to an LWP. */
static int
kill_lwp (int lwpid, int signo)
{
- errno = 0;
-
-/* Use tkill, if possible, in case we are using nptl threads. If tkill
- fails, then we are not using nptl threads and we should be using kill. */
+ /* Use tkill, if possible, in case we are using nptl threads. If tkill
+ fails, then we are not using nptl threads and we should be using kill. */
#ifdef HAVE_TKILL_SYSCALL
- if (!tkill_failed)
- {
- int ret = syscall (__NR_tkill, lwpid, signo);
- if (errno != ENOSYS)
- return ret;
- errno = 0;
- tkill_failed = 1;
- }
+ {
+ static int tkill_failed;
+
+ if (!tkill_failed)
+ {
+ int ret;
+
+ errno = 0;
+ ret = syscall (__NR_tkill, lwpid, signo);
+ if (errno != ENOSYS)
+ return ret;
+ tkill_failed = 1;
+ }
+ }
#endif
return kill (lwpid, signo);
Index: gdbserver/linux-low.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/linux-low.c,v
retrieving revision 1.117
diff -u -p -r1.117 linux-low.c
--- gdbserver/linux-low.c 21 Dec 2009 17:54:03 -0000 1.117
+++ gdbserver/linux-low.c 21 Dec 2009 20:39:15 -0000
@@ -1572,25 +1584,29 @@ linux_wait (ptid_t ptid,
return event_ptid;
}
-/* Send a signal to an LWP. For LinuxThreads, kill is enough; however, if
- thread groups are in use, we need to use tkill. */
+/* Send a signal to an LWP. */
static int
kill_lwp (unsigned long lwpid, int signo)
{
- static int tkill_failed;
+ /* Use tkill, if possible, in case we are using nptl threads. If tkill
+ fails, then we are not using nptl threads and we should be using kill. */
- errno = 0;
+#ifdef __NR_tkill
+ {
+ static int tkill_failed;
-#ifdef SYS_tkill
- if (!tkill_failed)
- {
- int ret = syscall (SYS_tkill, lwpid, signo);
- if (errno != ENOSYS)
- return ret;
- errno = 0;
- tkill_failed = 1;
- }
+ if (!tkill_failed)
+ {
+ int ret;
+
+ errno = 0;
+ ret = syscall (__NR_tkill, lwpid, signo);
+ if (errno != ENOSYS)
+ return ret;
+ tkill_failed = 1;
+ }
+ }
#endif
return kill (lwpid, signo);