Handle PTRACE_EVENT_EXIT to capture a final state snapshot

Also, it is now possible for interrupt_all_threads to fail to stop
threads in uninterruptable sleep (eg: the main thread during execve).

This may happen in more general cases as well, but it is now common
enough in that case to worry about.

Signed-off-by: Malfurious <m@lfurio.us>

1 files changed, 12 insertions, 2 deletions

diff --git a/debugger.c b/debugger.c
index 5981660..18f91e1 100644
--- a/debugger.c
+++ b/debugger.c
@@ -16,6 +16,7 @@
 static const int PTRACE_OPTIONS =
     PTRACE_O_TRACECLONE |
     PTRACE_O_TRACEEXEC  |
+    PTRACE_O_TRACEEXIT  |
     PTRACE_O_TRACESYSGOOD;
 
 static const int PTRACE_CHILD_OPTIONS = PTRACE_OPTIONS | PTRACE_O_EXITKILL;
@@ -258,7 +259,7 @@ static void resume_threads(struct process *proc) {
     int once = 0;
 
     for (struct thread *th = threads->head; th != threads->end; th = th->next) {
-        if (th->doing == PTRACE_SINGLESTEP) {
+        if (th->stopped && th->doing == PTRACE_SINGLESTEP) {
             ptrace(PTRACE_SINGLESTEP, th->id, NULL, th->signal);
             th->stopped = 0;
             th->signal = 0;
@@ -267,7 +268,7 @@ static void resume_threads(struct process *proc) {
     }
 
     for (struct thread *th = threads->head; th != threads->end; th = th->next) {
-        if (th->doing && th->doing != PTRACE_SINGLESTEP) {
+        if (th->stopped && th->doing && th->doing != PTRACE_SINGLESTEP) {
             if (!once) {
                 usleep(SCHEDULER_DELAY);
                 once = 1;
@@ -349,6 +350,15 @@ static int wait_thread(struct thread *th) {
                 th->state = NULL;
                 return 1;
 
+            case SIGTRAP | (PTRACE_EVENT_EXIT << 8):
+                th->stopped = 1;
+                th->signal = 0;
+                th->doing = PTRACE_CONT;
+                th->donext = 0;
+                strcpy(th->status, "EXITING");
+                th->state = NULL;
+                return 1;
+
             case SIGTRAP | (PTRACE_EVENT_STOP << 8):
                 th->stopped = 1;
                 th->signal = 0;