gdb, gdbserver: make status_to_str return std::string

Instead of using a static buffer.  This is safer, and we don't really
mind about any extra dynamic allocation here, since it's only used for
debug purposes.

gdb/ChangeLog:

	* nat/linux-waitpid.c (status_to_str): Return std::string.
	* nat/linux-waitpid.h (status_to_str): Likewise.
	* linux-nat.c (linux_nat_post_attach_wait): Adjust.
	(linux_nat_target::attach): Adjust.
	(linux_handle_extended_wait): Adjust.
	(wait_lwp): Adjust.
	(stop_wait_callback): Adjust.
	(linux_nat_filter_event): Adjust.
	(linux_nat_wait_1): Adjust.
	* nat/linux-waitpid.c (status_to_str): Adjust.
	* nat/linux-waitpid.h (status_to_str): Adjust.

gdbserver/ChangeLog:

	* linux-low.cc (linux_process_target::wait_for_event_filtered):
	Adjust to status_to_str returning std::string.

Change-Id: Ia8aead70270438a5690f243e6faafff6c38ff757

gdb/ChangeLog

@@ -1,3 +1,17 @@
+2021-05-08  Simon Marchi  <simon.marchi@polymtl.ca>
+
+	* nat/linux-waitpid.c (status_to_str): Return std::string.
+	* nat/linux-waitpid.h (status_to_str): Likewise.
+	* linux-nat.c (linux_nat_post_attach_wait): Adjust.
+	(linux_nat_target::attach): Adjust.
+	(linux_handle_extended_wait): Adjust.
+	(wait_lwp): Adjust.
+	(stop_wait_callback): Adjust.
+	(linux_nat_filter_event): Adjust.
+	(linux_nat_wait_1): Adjust.
+	* nat/linux-waitpid.c (status_to_str): Adjust.
+	* nat/linux-waitpid.h (status_to_str): Adjust.
+
 2021-05-08  Simon Marchi  <simon.marchi@polymtl.ca>
 
 	* infrun.h (infrun_debug_printf): Add missing space.

gdb/linux-nat.c

@@ -1061,7 +1061,7 @@ linux_nat_post_attach_wait (ptid_t ptid, int *signalled)
     {
       /* The pid we tried to attach has apparently just exited.  */
       linux_nat_debug_printf ("Failed to stop %d: %s", pid,
-			      status_to_str (status));
+			      status_to_str (status).c_str ());
       return status;
     }
 
@@ -1069,7 +1069,7 @@ linux_nat_post_attach_wait (ptid_t ptid, int *signalled)
     {
       *signalled = 1;
       linux_nat_debug_printf ("Received %s after attaching",
-			      status_to_str (status));
+			      status_to_str (status).c_str ());
     }
 
   return status;
@@ -1239,7 +1239,8 @@ linux_nat_target::attach (const char *args, int from_tty)
   /* Save the wait status to report later.  */
   lp->resumed = 1;
   linux_nat_debug_printf ("waitpid %ld, saving status %s",
-			  (long) lp->ptid.pid (), status_to_str (status));
+			  (long) lp->ptid.pid (),
+			  status_to_str (status).c_str ());
 
   lp->status = status;
 
@@ -2005,7 +2006,7 @@ linux_handle_extended_wait (struct lwp_info *lp, int status)
 	      /* Save the wait status to report later.  */
 	      linux_nat_debug_printf
 		("waitpid of new LWP %ld, saving status %s",
-		 (long) new_lp->ptid.lwp (), status_to_str (status));
+		 (long) new_lp->ptid.lwp (), status_to_str (status).c_str ());
 	      new_lp->status = status;
 	    }
 	  else if (report_thread_events)
@@ -2153,7 +2154,7 @@ wait_lwp (struct lwp_info *lp)
 
       linux_nat_debug_printf ("waitpid %s received %s",
 			      target_pid_to_str (lp->ptid).c_str (),
-			      status_to_str (status));
+			      status_to_str (status).c_str ());
 
       /* Check if the thread has exited.  */
       if (WIFEXITED (status) || WIFSIGNALED (status))
@@ -2440,7 +2441,7 @@ stop_wait_callback (struct lwp_info *lp)
 	  /* The thread was stopped with a signal other than SIGSTOP.  */
 
 	  linux_nat_debug_printf ("Pending event %s in %s",
-				  status_to_str ((int) status),
+				  status_to_str ((int) status).c_str (),
 				  target_pid_to_str (lp->ptid).c_str ());
 
 	  /* Save the sigtrap event.  */
@@ -2859,7 +2860,7 @@ linux_nat_filter_event (int lwpid, int status)
   if (WIFSTOPPED (status) && !lp)
     {
       linux_nat_debug_printf ("saving LWP %ld status %s in stopped_pids list",
-			      (long) lwpid, status_to_str (status));
+			      (long) lwpid, status_to_str (status).c_str ());
       add_to_pid_list (&stopped_pids, lwpid, status);
       return;
     }
@@ -3152,7 +3153,7 @@ linux_nat_wait_1 (ptid_t ptid, struct target_waitstatus *ourstatus,
   if (lp != NULL)
     {
       linux_nat_debug_printf ("Using pending wait status %s for %s.",
-			      status_to_str (lp->status),
+			      status_to_str (lp->status).c_str (),
 			      target_pid_to_str (lp->ptid).c_str ());
     }
 
@@ -3187,7 +3188,8 @@ linux_nat_wait_1 (ptid_t ptid, struct target_waitstatus *ourstatus,
       if (lwpid > 0)
 	{
 	  linux_nat_debug_printf ("waitpid %ld received %s",
-				  (long) lwpid, status_to_str (status));
+				  (long) lwpid,
+				  status_to_str (status).c_str ());
 
 	  linux_nat_filter_event (lwpid, status);
 	  /* Retry until nothing comes out of waitpid.  A single

gdb/nat/linux-waitpid.c

@@ -24,30 +24,25 @@
 #include "gdbsupport/gdb_wait.h"
 #include "gdbsupport/eintr.h"
 
-/* Convert wait status STATUS to a string.  Used for printing debug
+/* See linux-waitpid.h.  */
-   messages only.  */
 
-char *
+std::string
 status_to_str (int status)
 {
-  static char buf[64];
-
   if (WIFSTOPPED (status))
     {
       if (WSTOPSIG (status) == SYSCALL_SIGTRAP)
-	snprintf (buf, sizeof (buf), "%s (stopped at syscall)",
+	return string_printf ("%s (stopped at syscall)",
-		  strsignal (SIGTRAP));
+			      strsignal (SIGTRAP));
       else
-	snprintf (buf, sizeof (buf), "%s (stopped)",
+	return string_printf ("%s (stopped)",
-		  strsignal (WSTOPSIG (status)));
+			      strsignal (WSTOPSIG (status)));
     }
   else if (WIFSIGNALED (status))
-    snprintf (buf, sizeof (buf), "%s (terminated)",
+    return string_printf ("%s (terminated)",
-	      strsignal (WTERMSIG (status)));
+			  strsignal (WTERMSIG (status)));
   else
-    snprintf (buf, sizeof (buf), "%d (exited)", WEXITSTATUS (status));
+    return string_printf ("%d (exited)", WEXITSTATUS (status));
-
-  return buf;
 }
 
 /* See linux-waitpid.h.  */

gdb/nat/linux-waitpid.h

@@ -25,6 +25,6 @@ extern int my_waitpid (int pid, int *status, int flags);
 
 /* Convert wait status STATUS to a string.  Used for printing debug
    messages only.  */
-extern char *status_to_str (int status);
+extern std::string status_to_str (int status);
 
 #endif /* NAT_LINUX_WAITPID_H */

gdbserver/ChangeLog

@@ -1,3 +1,8 @@
+2021-05-08  Simon Marchi  <simon.marchi@polymtl.ca>
+
+	* linux-low.cc (linux_process_target::wait_for_event_filtered):
+	Adjust to status_to_str returning std::string.
+
 2021-05-08  Pedro Alves  <pedro@palves.net>
 
 	* linux-low.cc:

gdbserver/linux-low.cc

@@ -2601,7 +2601,7 @@ linux_process_target::wait_for_event_filtered (ptid_t wait_ptid,
 	  if (debug_threads)
 	    {
 	      debug_printf ("LLW: waitpid %ld received %s\n",
-			    (long) ret, status_to_str (*wstatp));
+			    (long) ret, status_to_str (*wstatp).c_str ());
 	    }
 
 	  /* Filter all events.  IOW, leave all events pending.  We'll