From: Andrew Burgess <andrew.burgess@embecosm.com>
Date: Tue, 3 Jul 2018 18:02:48 +0000 (+0100)
Subject: gdb: Avoid using W_STOPCODE(0) as this is ambiguous on MIPS
X-Git-Tag: users/ARM/embedded-binutils-master-2018q4~1172
X-Git-Url: https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commitdiff_plain;h=953473375500a809fbb3eca3efa4dbb670c3a32f
gdb: Avoid using W_STOPCODE(0) as this is ambiguous on MIPS
The MIPS target supports 127 signals, and this can create an ambiguity
in process wait statuses. A status value of 0x007f could potentially
indicate a process that has exited with signal 127, or a process that
has stopped with signal 0.
In uClibc-ng the interpretation of 0x007f is that the process has
exited with signal 127 rather than stopped with signal 0, and so,
WIFSTOPPED (W_STOPCODE (0)) will be false rather than true as it would
be on most other platforms.
Given that it's pretty easy to avoid using W_STOPCODE (0), lets do that.
gdb/ChangeLog:
* linux-nat.c (linux_nat_target::follow_fork): Avoid using
'W_STOPCODE (0)' as this could be ambiguous.
---
diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c
index 86d3dfd..d2c88ad 100644
--- a/gdb/linux-nat.c
+++ b/gdb/linux-nat.c
@@ -445,7 +445,6 @@ linux_nat_target::follow_fork (int follow_child, int detach_fork)
if (!follow_child)
{
struct lwp_info *child_lp = NULL;
- int status = W_STOPCODE (0);
int has_vforked;
ptid_t parent_ptid, child_ptid;
int parent_pid, child_pid;
@@ -465,6 +464,8 @@ linux_nat_target::follow_fork (int follow_child, int detach_fork)
/* Detach new forked process? */
if (detach_fork)
{
+ int child_stop_signal = 0;
+ bool detach_child = true;
struct cleanup *old_chain = make_cleanup (delete_lwp_cleanup,
child_lp);
@@ -484,18 +485,24 @@ linux_nat_target::follow_fork (int follow_child, int detach_fork)
if (!gdbarch_software_single_step_p (target_thread_architecture
(parent_ptid)))
{
+ int status;
+
linux_disable_event_reporting (child_pid);
if (ptrace (PTRACE_SINGLESTEP, child_pid, 0, 0) < 0)
perror_with_name (_("Couldn't do single step"));
if (my_waitpid (child_pid, &status, 0) < 0)
perror_with_name (_("Couldn't wait vfork process"));
+ else
+ {
+ detach_child = WIFSTOPPED (status);
+ child_stop_signal = WSTOPSIG (status);
+ }
}
- if (WIFSTOPPED (status))
+ if (detach_child)
{
- int signo;
+ int signo = child_stop_signal;
- signo = WSTOPSIG (status);
if (signo != 0
&& !signal_pass_state (gdb_signal_from_host (signo)))
signo = 0;
