diff mbox

[OB/PUSHED,GDB/Linux] Avoid stale errno

Message ID 53C549B0.70602@gmail.com
State Committed
Headers

Commit Message

Pedro Alves July 15, 2014, 3:33 p.m. UTC 
  ... and I knew I was forgetting something.  The same fix is needed
on the GDB side.

Pushed.

---------
From: Pedro Alves <palves@redhat.com>
Subject: [PATCH] [GDB/Linux] Avoid stale errno

The fix that went into GDBserver is also needed on the GDB side.

Although most compilers follow right-to-left evaluation order, the
order of evaluation of a function call's arguments is really
unspecified.  target_pid_to_str may well clobber errno when we get to
evaluate the third argument to fprintf_unfiltered.

gdb/
2014-07-15  Pedro Alves  <palves@redhat.com>

	* linux-nat.c (kill_callback): Save errno and work with saved
	copy.
---
 gdb/ChangeLog   |  5 +++++
 gdb/linux-nat.c | 24 ++++++++++++++++--------
 2 files changed, 21 insertions(+), 8 deletions(-)
diff mbox

Patch

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 157dc49..2b6604b 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@ 
+2014-07-15  Pedro Alves  <palves@redhat.com>
+
+	* linux-nat.c (kill_callback): Save errno and work with saved
+	copy.
+
 2014-07-15  Simon Marchi  <simon.marchi@ericsson.com>

 	* expprint.c (dump_subexp_body_standard): Handle OP_STRING.
diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c
index 0ab0362..c738abf 100644
--- a/gdb/linux-nat.c
+++ b/gdb/linux-nat.c
@@ -3706,20 +3706,28 @@  kill_callback (struct lwp_info *lp, void *data)
   errno = 0;
   kill (ptid_get_lwp (lp->ptid), SIGKILL);
   if (debug_linux_nat)
-    fprintf_unfiltered (gdb_stdlog,
-			"KC:  kill (SIGKILL) %s, 0, 0 (%s)\n",
-			target_pid_to_str (lp->ptid),
-			errno ? safe_strerror (errno) : "OK");
+    {
+      int save_errno = errno;
+
+      fprintf_unfiltered (gdb_stdlog,
+			  "KC:  kill (SIGKILL) %s, 0, 0 (%s)\n",
+			  target_pid_to_str (lp->ptid),
+			  save_errno ? safe_strerror (save_errno) : "OK");
+    }

   /* Some kernels ignore even SIGKILL for processes under ptrace.  */

   errno = 0;
   ptrace (PTRACE_KILL, ptid_get_lwp (lp->ptid), 0, 0);
   if (debug_linux_nat)
-    fprintf_unfiltered (gdb_stdlog,
-			"KC:  PTRACE_KILL %s, 0, 0 (%s)\n",
-			target_pid_to_str (lp->ptid),
-			errno ? safe_strerror (errno) : "OK");
+    {
+      int save_errno = errno;
+
+      fprintf_unfiltered (gdb_stdlog,
+			  "KC:  PTRACE_KILL %s, 0, 0 (%s)\n",
+			  target_pid_to_str (lp->ptid),
+			  save_errno ? safe_strerror (save_errno) : "OK");
+    }

   return 0;
 }