commit 05a1f2ac4c65d83783e084b0942ddbe94347d2d4
author Pavel Labath <labath@google.com> Thu May 28 08:59:21 2015 +0000
committer Pavel Labath <labath@google.com> Thu May 28 08:59:21 2015 +0000
tree 2c13693475f68b3bb1b1fdcb360c28ec29652662
parent e1326cadb288012ab1d37ec10d3244dc8b2d6f5b

[NativeProcessLinux] Support inferiors which change their process group

Summary:
Previously, we wait()ed for events from the inferiors process group. This is resulted in a
failure if the inferior changed its process group in the middle of execution. To avoid this, I
pass -1 to the wait() call. The flag __WNOTHREAD makes sure we don't actually wait for events
from any process, but only the processes(threads) which are our children (or traced by us). Since
this happens on the monitor thread, which is dedicated to monitoring a single inferior, we will
be getting events only from this inferior.

Test Plan: All tests pass on linux. I have added a test to check the new functionality.

Reviewers: chaoren, ovyalov

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D10061

llvm-svn: 238405

lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp

diff --git a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
index 325fdde..489890a 100644
--- a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
+++ b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
@@ -786,7 +786,7 @@
     while (true)
     {
         int status = -1;
-        ::pid_t wait_pid = waitpid(m_child_pid, &status, __WALL | WNOHANG);
+        ::pid_t wait_pid = waitpid(-1, &status, __WALL | __WNOTHREAD | WNOHANG);
 
         if (wait_pid == 0)
             break; // We are done.
@@ -797,8 +797,8 @@
                 continue;
 
             if (log)
-              log->Printf("NativeProcessLinux::Monitor::%s waitpid (pid = %" PRIi32 ", &status, __WALL | WNOHANG) failed: %s",
-                      __FUNCTION__, m_child_pid, strerror(errno));
+              log->Printf("NativeProcessLinux::Monitor::%s waitpid (-1, &status, __WALL | __WNOTHREAD | WNOHANG) failed: %s",
+                      __FUNCTION__, strerror(errno));
             break;
         }
 
@@ -821,7 +821,7 @@
         {
             signal = WTERMSIG(status);
             status_cstr = "SIGNALED";
-            if (wait_pid == abs(m_child_pid)) {
+            if (wait_pid == m_child_pid) {
                 exited = true;
                 exit_status = -1;
             }
@@ -830,9 +830,9 @@
             status_cstr = "(\?\?\?)";
 
         if (log)
-            log->Printf("NativeProcessLinux::Monitor::%s: waitpid (pid = %" PRIi32 ", &status, __WALL | WNOHANG)"
+            log->Printf("NativeProcessLinux::Monitor::%s: waitpid (-1, &status, __WALL | __WNOTHREAD | WNOHANG)"
                 "=> pid = %" PRIi32 ", status = 0x%8.8x (%s), signal = %i, exit_state = %i",
-                __FUNCTION__, m_child_pid, wait_pid, status, status_cstr, signal, exit_status);
+                __FUNCTION__, wait_pid, status, status_cstr, signal, exit_status);
 
         m_native_process->MonitorCallback (wait_pid, exited, signal, exit_status);
     }
@@ -893,7 +893,7 @@
 {
     ::pid_t child_pid = (*m_initial_operation_up)(m_operation_error);
     m_initial_operation_up.reset();
-    m_child_pid = -getpgid(child_pid),
+    m_child_pid = child_pid;
     sem_post(&m_operation_sem);
 
     while (true)