Add ability to attach/detach to multi-threaded inferiors on Linux.
All running threads will be detected and stopped on attach and all threads get resumed on detach.
llvm-svn: 183049
diff --git a/lldb/source/Plugins/Process/Linux/ProcessMonitor.cpp b/lldb/source/Plugins/Process/Linux/ProcessMonitor.cpp
index 0ba8840..7832c7b 100644
--- a/lldb/source/Plugins/Process/Linux/ProcessMonitor.cpp
+++ b/lldb/source/Plugins/Process/Linux/ProcessMonitor.cpp
@@ -857,22 +857,20 @@
class DetachOperation : public Operation
{
public:
- DetachOperation(Error &result) : m_error(result) { }
+ DetachOperation(lldb::tid_t tid, Error &result) : m_tid(tid), m_error(result) { }
void Execute(ProcessMonitor *monitor);
private:
+ lldb::tid_t m_tid;
Error &m_error;
};
void
DetachOperation::Execute(ProcessMonitor *monitor)
{
- lldb::pid_t pid = monitor->GetPID();
-
- if (ptrace(PT_DETACH, pid, NULL, 0) < 0)
+ if (ptrace(PT_DETACH, m_tid, NULL, 0) < 0)
m_error.SetErrorToErrno();
-
}
ProcessMonitor::OperationArgs::OperationArgs(ProcessMonitor *monitor)
@@ -1098,7 +1096,6 @@
const size_t err_len = 1024;
char err_str[err_len];
lldb::pid_t pid;
- long ptrace_opts = 0;
lldb::ThreadSP inferior;
Log *log (ProcessPOSIXLog::GetLogIfAllCategoriesSet (POSIX_LOG_PROCESS));
@@ -1214,20 +1211,7 @@
assert(WIFSTOPPED(status) && wpid == pid &&
"Could not sync with inferior process.");
- // Have the child raise an event on exit. This is used to keep the child in
- // limbo until it is destroyed.
- ptrace_opts |= PTRACE_O_TRACEEXIT;
-
- // Have the tracer trace threads which spawn in the inferior process.
- // TODO: if we want to support tracing the inferiors' child, add the
- // appropriate ptrace flags here (PTRACE_O_TRACEFORK, PTRACE_O_TRACEVFORK)
- ptrace_opts |= PTRACE_O_TRACECLONE;
-
- // Have the tracer notify us before execve returns
- // (needed to disable legacy SIGTRAP generation)
- ptrace_opts |= PTRACE_O_TRACEEXEC;
-
- if (PTRACE(PTRACE_SETOPTIONS, pid, NULL, (void*)ptrace_opts, 0) < 0)
+ if (!SetDefaultPtraceOpts(pid))
{
args->m_error.SetErrorToErrno();
goto FINISH;
@@ -1308,6 +1292,9 @@
lldb::ThreadSP inferior;
Log *log (ProcessPOSIXLog::GetLogIfAllCategoriesSet (POSIX_LOG_PROCESS));
+ // Use a map to keep track of the threads which we have attached/need to attach.
+ Host::TidMap tids_to_attach;
+
if (pid <= 1)
{
args->m_error.SetErrorToGenericError();
@@ -1315,36 +1302,106 @@
goto FINISH;
}
- // Attach to the requested process.
- if (PTRACE(PTRACE_ATTACH, pid, NULL, NULL, 0) < 0)
+ while (Host::FindProcessThreads(pid, tids_to_attach))
{
- args->m_error.SetErrorToErrno();
- goto FINISH;
+ for (Host::TidMap::iterator it = tids_to_attach.begin();
+ it != tids_to_attach.end(); ++it)
+ {
+ if (it->second == false)
+ {
+ lldb::tid_t tid = it->first;
+
+ // Attach to the requested process.
+ // An attach will cause the thread to stop with a SIGSTOP.
+ if (PTRACE(PTRACE_ATTACH, tid, NULL, NULL, 0) < 0)
+ {
+ // No such thread. The thread may have exited.
+ // More error handling may be needed.
+ if (errno == ESRCH)
+ {
+ tids_to_attach.erase(it);
+ continue;
+ }
+ else
+ {
+ args->m_error.SetErrorToErrno();
+ goto FINISH;
+ }
+ }
+
+ int status;
+ // Need to use __WALL otherwise we receive an error with errno=ECHLD
+ // At this point we should have a thread stopped if waitpid succeeds.
+ if ((status = waitpid(tid, NULL, __WALL)) < 0)
+ {
+ // No such thread. The thread may have exited.
+ // More error handling may be needed.
+ if (errno == ESRCH)
+ {
+ tids_to_attach.erase(it);
+ continue;
+ }
+ else
+ {
+ args->m_error.SetErrorToErrno();
+ goto FINISH;
+ }
+ }
+
+ if (!SetDefaultPtraceOpts(tid))
+ {
+ args->m_error.SetErrorToErrno();
+ goto FINISH;
+ }
+
+ // Update the process thread list with the attached thread.
+ inferior.reset(new POSIXThread(process, tid));
+ if (log)
+ log->Printf ("ProcessMonitor::%s() adding tid = %" PRIu64, __FUNCTION__, tid);
+ process.GetThreadList().AddThread(inferior);
+ it->second = true;
+ }
+ }
}
- int status;
- if ((status = waitpid(pid, NULL, 0)) < 0)
+ if (tids_to_attach.size() > 0)
{
- args->m_error.SetErrorToErrno();
- goto FINISH;
+ monitor->m_pid = pid;
+ // Let our process instance know the thread has stopped.
+ process.SendMessage(ProcessMessage::Trace(pid));
}
-
- monitor->m_pid = pid;
-
- // Update the process thread list with the attached thread.
- inferior.reset(new POSIXThread(process, pid));
- if (log)
- log->Printf ("ProcessMonitor::%s() adding tid = %" PRIu64, __FUNCTION__, pid);
- process.GetThreadList().AddThread(inferior);
-
- // Let our process instance know the thread has stopped.
- process.SendMessage(ProcessMessage::Trace(pid));
+ else
+ {
+ args->m_error.SetErrorToGenericError();
+ args->m_error.SetErrorString("No such process.");
+ }
FINISH:
return args->m_error.Success();
}
bool
+ProcessMonitor::SetDefaultPtraceOpts(lldb::pid_t pid)
+{
+ long ptrace_opts = 0;
+
+ // Have the child raise an event on exit. This is used to keep the child in
+ // limbo until it is destroyed.
+ ptrace_opts |= PTRACE_O_TRACEEXIT;
+
+ // Have the tracer trace threads which spawn in the inferior process.
+ // TODO: if we want to support tracing the inferiors' child, add the
+ // appropriate ptrace flags here (PTRACE_O_TRACEFORK, PTRACE_O_TRACEVFORK)
+ ptrace_opts |= PTRACE_O_TRACECLONE;
+
+ // Have the tracer notify us before execve returns
+ // (needed to disable legacy SIGTRAP generation)
+ ptrace_opts |= PTRACE_O_TRACEEXEC;
+
+ return PTRACE(PTRACE_SETOPTIONS, pid, NULL, (void*)ptrace_opts, 0) >= 0;
+}
+
+bool
ProcessMonitor::MonitorCallback(void *callback_baton,
lldb::pid_t pid,
bool exited,
@@ -2047,11 +2104,12 @@
}
lldb_private::Error
-ProcessMonitor::Detach()
+ProcessMonitor::Detach(lldb::tid_t tid)
{
lldb_private::Error error;
- if (m_pid != LLDB_INVALID_PROCESS_ID) {
- DetachOperation op(error);
+ if (tid != LLDB_INVALID_THREAD_ID)
+ {
+ DetachOperation op(tid, error);
DoOperation(&op);
}
return error;