gdb/gdb-attach-fail-reasons-1of5.patch

89 lines
2.6 KiB
Diff

http://sourceware.org/ml/gdb-cvs/2012-02/msg00180.html
### src/gdb/gdbserver/ChangeLog 2012/02/25 19:54:50 1.556
### src/gdb/gdbserver/ChangeLog 2012/02/27 16:19:19 1.557
## -1,3 +1,9 @@
+2012-02-27 Pedro Alves <palves@redhat.com>
+
+ PR server/9684
+ * linux-low.c (pid_is_stopped): New.
+ (linux_attach_lwp_1): Handle attaching to 'T (stopped)' processes.
+
2012-02-25 Luis Machado <lgustavo@codesourcery.com>
* mem-break.c (clear_gdb_breakpoint_conditions): Fix de-allocation
--- src/gdb/gdbserver/linux-low.c 2012/02/24 15:15:56 1.193
+++ src/gdb/gdbserver/linux-low.c 2012/02/27 16:19:19 1.194
@@ -598,6 +598,37 @@
return pid;
}
+/* Detect `T (stopped)' in `/proc/PID/status'.
+ Other states including `T (tracing stop)' are reported as false. */
+
+static int
+pid_is_stopped (pid_t pid)
+{
+ FILE *status_file;
+ char buf[100];
+ int retval = 0;
+
+ snprintf (buf, sizeof (buf), "/proc/%d/status", (int) pid);
+ status_file = fopen (buf, "r");
+ if (status_file != NULL)
+ {
+ int have_state = 0;
+
+ while (fgets (buf, sizeof (buf), status_file))
+ {
+ if (strncmp (buf, "State:", 6) == 0)
+ {
+ have_state = 1;
+ break;
+ }
+ }
+ if (have_state && strstr (buf, "T (stopped)") != NULL)
+ retval = 1;
+ fclose (status_file);
+ }
+ return retval;
+}
+
/* Attach to an inferior process. */
static void
@@ -643,6 +674,33 @@
ptrace call on this LWP. */
new_lwp->must_set_ptrace_flags = 1;
+ if (pid_is_stopped (lwpid))
+ {
+ if (debug_threads)
+ fprintf (stderr,
+ "Attached to a stopped process\n");
+
+ /* The process is definitely stopped. It is in a job control
+ stop, unless the kernel predates the TASK_STOPPED /
+ TASK_TRACED distinction, in which case it might be in a
+ ptrace stop. Make sure it is in a ptrace stop; from there we
+ can kill it, signal it, et cetera.
+
+ First make sure there is a pending SIGSTOP. Since we are
+ already attached, the process can not transition from stopped
+ to running without a PTRACE_CONT; so we know this signal will
+ go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
+ probably already in the queue (unless this kernel is old
+ enough to use TASK_STOPPED for ptrace stops); but since
+ SIGSTOP is not an RT signal, it can only be queued once. */
+ kill_lwp (lwpid, SIGSTOP);
+
+ /* Finally, resume the stopped process. This will deliver the
+ SIGSTOP (or a higher priority signal, just like normal
+ PTRACE_ATTACH), which we'll catch later on. */
+ ptrace (PTRACE_CONT, lwpid, 0, 0);
+ }
+
/* The next time we wait for this LWP we'll see a SIGSTOP as PTRACE_ATTACH
brings it to a halt.