[PATCH v5 12/15] fbsd-nat: Return nullptr rather than failing ::thread_name.

[John Baldwin <jhb@FreeBSD.org>]

ptrace on FreeBSD cannot be used against running processes and instead
fails with EBUSY.  This meant that 'info threads' would fail if any of
the threads were running (for example when using schedule-multiple=on
in gdb.base/fork-running-state.exp).  Instead of throwing errors, just
return nullptr as no thread name is better than causing info threads to
fail completely.
---
 gdb/fbsd-nat.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/gdb/fbsd-nat.c b/gdb/fbsd-nat.c
index 3f36ebaef52..13b4386fd2e 100644
--- a/gdb/fbsd-nat.c
+++ b/gdb/fbsd-nat.c
@@ -820,9 +820,9 @@ fbsd_nat_target::thread_name (struct thread_info *thr)
      if a name has not been set explicitly.  Return a NULL name in
      that case.  */
   if (!fbsd_fetch_kinfo_proc (pid, &kp))
-    perror_with_name (_("Failed to fetch process information"));
+    return nullptr;
   if (ptrace (PT_LWPINFO, lwp, (caddr_t) &pl, sizeof pl) == -1)
-    perror_with_name (("ptrace (PT_LWPINFO)"));
+    return nullptr;
   if (strcmp (kp.ki_comm, pl.pl_tdname) == 0)
     return NULL;
   xsnprintf (buf, sizeof buf, "%s", pl.pl_tdname);
-- 
2.34.1