Add support for live debugging of multi-threaded code.

2 files changed, 93 insertions, 0 deletions

diff --git a/gnu/usr.bin/binutils/gdb/obsd-nat.c b/gnu/usr.bin/binutils/gdb/obsd-nat.c
index 56474369968..3dd8ec893bb 100644
--- a/gnu/usr.bin/binutils/gdb/obsd-nat.c
+++ b/gnu/usr.bin/binutils/gdb/obsd-nat.c
@@ -24,8 +24,10 @@
 #include "inferior.h"
 #include "target.h"
 
+#include "gdb_assert.h"
 #include <sys/types.h>
 #include <sys/ptrace.h>
+#include <sys/wait.h>
 
 #include "obsd-nat.h"
 
@@ -69,3 +71,93 @@ obsd_find_new_threads (void)
 	perror_with_name (("ptrace"));
     }
 }
+
+ptid_t
+obsd_wait (ptid_t ptid, struct target_waitstatus *ourstatus)
+{
+  pid_t pid;
+  int status, save_errno;
+
+  do
+    {
+      set_sigint_trap ();
+      set_sigio_trap ();
+
+      do
+	{
+	  pid = waitpid (ptid_get_pid (ptid), &status, 0);
+	  save_errno = errno;
+	}
+      while (pid == -1 && errno == EINTR);
+
+      clear_sigio_trap ();
+      clear_sigint_trap ();
+
+      if (pid == -1)
+	{
+	  fprintf_unfiltered (gdb_stderr,
+			      _("Child process unexpectedly missing: %s.\n"),
+			      safe_strerror (save_errno));
+
+	  /* Claim it exited with unknown signal.  */
+	  ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
+	  ourstatus->value.sig = TARGET_SIGNAL_UNKNOWN;
+	  return minus_one_ptid;
+	}
+
+      /* Ignore terminated detached child processes.  */
+      if (!WIFSTOPPED (status) && pid != ptid_get_pid (inferior_ptid))
+	pid = -1;
+    }
+  while (pid == -1);
+
+  ptid = pid_to_ptid (pid);
+
+  if (WIFSTOPPED (status))
+    {
+      ptrace_state_t pe;
+      pid_t fpid;
+
+      if (ptrace (PT_GET_PROCESS_STATE, pid, (caddr_t)&pe, sizeof pe) == -1)
+	perror_with_name (("ptrace"));
+
+      switch (pe.pe_report_event)
+	{
+	case PTRACE_FORK:
+	  ourstatus->kind = TARGET_WAITKIND_FORKED;
+	  ourstatus->value.related_pid = pe.pe_other_pid;
+
+	  /* Make sure the other end of the fork is stopped too.  */
+	  fpid = waitpid (pe.pe_other_pid, &status, 0);
+	  if (fpid == -1)
+	    perror_with_name (("waitpid"));
+
+	  if (ptrace (PT_GET_PROCESS_STATE, fpid,
+		      (caddr_t)&pe, sizeof pe) == -1)
+	    perror_with_name (("ptrace"));
+
+	  gdb_assert (pe.pe_report_event == PTRACE_FORK);
+	  gdb_assert (pe.pe_other_pid == pid);
+	  if (fpid == ptid_get_pid (inferior_ptid))
+	    {
+	      ourstatus->value.related_pid = pe.pe_other_pid;
+	      return pid_to_ptid (fpid);
+	    }
+
+	  return pid_to_ptid (pid);
+	}
+
+      ptid = ptid_build (pid, pe.pe_tid, 0);
+      if (!in_thread_list (ptid))
+	{
+	  /* HACK: Twiddle INFERIOR_PTID such that the initial thread
+	     of a process isn't recognized as a new thread.  */
+	  if (ptid_get_lwp (inferior_ptid) == 0)
+	    inferior_ptid = ptid;
+	  add_thread (ptid);
+	}
+    }
+
+  store_waitstatus (ourstatus, status);
+  return ptid;
+}
diff --git a/gnu/usr.bin/binutils/gdb/obsd-nat.h b/gnu/usr.bin/binutils/gdb/obsd-nat.h
index a2bae58e1e8..f30670d480b 100644
--- a/gnu/usr.bin/binutils/gdb/obsd-nat.h
+++ b/gnu/usr.bin/binutils/gdb/obsd-nat.h
@@ -24,5 +24,6 @@
 
 extern char *obsd_pid_to_str (ptid_t ptid);
 extern void obsd_find_new_threads (void);
+extern ptid_t obsd_wait (ptid_t ptid, struct target_waitstatus *ourstatus);
 
 #endif /* obsd-nat.h */