fbsd-nat: Implement async target support.

This is a fairly simple version of async target support.

Synchronous mode still uses blocking waitpid() calls in
inf_ptrace::wait() unlike the Linux native target which always uses
WNOHANG and uses sigsuspend() for synchronous operation.

Asynchronous mode registers an event pipe with the core as a file
handle and writes to the pipe when SIGCHLD is raised.  TARGET_WNOHANG
is handled by inf_ptrace::wait().

1 files changed, 12 insertions, 0 deletions

diff --git a/gdb/fbsd-nat.h b/gdb/fbsd-nat.h
index b32cabb..411573b 100644
--- a/gdb/fbsd-nat.h
+++ b/gdb/fbsd-nat.h
@@ -66,9 +66,19 @@ public:
 
   void update_thread_list () override;
 
+  bool can_async_p () override;
+  bool is_async_p () override;
+
+  int async_wait_fd () override;
+  void async (int) override;
+
+  void close () override;
+
   thread_control_capabilities get_thread_control_capabilities () override
   { return tc_schedlock; }
 
+  void attach (const char *, int) override;
+
   void create_inferior (const char *, const std::string &,
 			char **, int) override;
 
@@ -110,6 +120,8 @@ protected:
   void post_startup_inferior (ptid_t) override;
 
 private:
+  ptid_t wait_1 (ptid_t, struct target_waitstatus *, target_wait_flags);
+
   /* Helper routines for use in fetch_registers and store_registers in
      subclasses.  These routines fetch and store a single set of
      registers described by REGSET.  The REGSET's 'regmap' field must