gdbserver: set ptrace flags after creating inferiors

Rename target_ops.arch_setup to .post_create_inferior.  In the Linux
hook, continue calling the low arch setup, then also set ptrace flags.
This corrects the possibility of running without flags, demonstrated by
a new test that would fail to catch a fork before.

gdb/gdbserver/ChangeLog:

2015-12-04  Josh Stone  <jistone@redhat.com>

	* target.h (struct target_ops) <arch_setup>: Rename to ...
	(struct target_ops) <post_create_inferior>: ... this.
	(target_arch_setup): Rename to ...
	(target_post_create_inferior): ... this, calling post_create_inferior.
	* server.c (start_inferior): Update target_arch_setup calls to
	target_post_create_inferior.
	* linux-low.c (linux_low_ptrace_options): Forward declare.
	(linux_arch_setup): Update its comment for general use.
	(linux_post_create_inferior): New, run arch_setup and setup ptrace.
	(struct linux_target_ops): Use linux_post_create_inferior.
	* lynx-low.c (struct lynx_target_ops): Update arch_setup stub comment
	to post_create_inferior.
	* nto-low.c (struct nto_target_ops): Likewise.
	* spu-low.c (struct spu_target_ops): Likewise.
	* win32-low.c (struct win32_target_ops): Likewise.

gdb/testsuite/ChangeLog:

2015-12-04  Josh Stone  <jistone@redhat.com>

	* gdb.base/catch-fork-static.exp: New.

gdb/gdbserver/ChangeLog

@@ -1,3 +1,21 @@
+2015-12-04  Josh Stone  <jistone@redhat.com>
+
+	* target.h (struct target_ops) <arch_setup>: Rename to ...
+	(struct target_ops) <post_create_inferior>: ... this.
+	(target_arch_setup): Rename to ...
+	(target_post_create_inferior): ... this, calling post_create_inferior.
+	* server.c (start_inferior): Update target_arch_setup calls to
+	target_post_create_inferior.
+	* linux-low.c (linux_low_ptrace_options): Forward declare.
+	(linux_arch_setup): Update its comment for general use.
+	(linux_post_create_inferior): New, run arch_setup and setup ptrace.
+	(struct linux_target_ops): Use linux_post_create_inferior.
+	* lynx-low.c (struct lynx_target_ops): Update arch_setup stub comment
+	to post_create_inferior.
+	* nto-low.c (struct nto_target_ops): Likewise.
+	* spu-low.c (struct spu_target_ops): Likewise.
+	* win32-low.c (struct win32_target_ops): Likewise.
+
 2015-12-03  Antoine Tremblay  <antoine.tremblay@ericsson.com>
 
 	* linux-arm-low.c: Remove duplicate arch/arm.h include.

gdb/gdbserver/linux-low.c

@@ -264,6 +264,7 @@ static int finish_step_over (struct lwp_info *lwp);
 static int kill_lwp (unsigned long lwpid, int signo);
 static void enqueue_pending_signal (struct lwp_info *lwp, int signal, siginfo_t *info);
 static void complete_ongoing_step_over (void);
+static int linux_low_ptrace_options (int attached);
 
 /* When the event-loop is doing a step-over, this points at the thread
    being stepped.  */
@@ -421,7 +422,7 @@ linux_add_process (int pid, int attached)
 
 static CORE_ADDR get_pc (struct lwp_info *lwp);
 
-/* Implement the arch_setup target_ops method.  */
+/* Call the target arch_setup function on the current thread.  */
 
 static void
 linux_arch_setup (void)
@@ -919,6 +920,25 @@ linux_create_inferior (char *program, char **allargs)
   return pid;
 }
 
+/* Implement the post_create_inferior target_ops method.  */
+
+static void
+linux_post_create_inferior (void)
+{
+  struct lwp_info *lwp = get_thread_lwp (current_thread);
+
+  linux_arch_setup ();
+
+  if (lwp->must_set_ptrace_flags)
+    {
+      struct process_info *proc = current_process ();
+      int options = linux_low_ptrace_options (proc->attached);
+
+      linux_enable_event_reporting (lwpid_of (current_thread), options);
+      lwp->must_set_ptrace_flags = 0;
+    }
+}
+
 /* Attach to an inferior process.  Returns 0 on success, ERRNO on
    error.  */
 
@@ -7077,7 +7097,7 @@ linux_breakpoint_kind_from_current_state (CORE_ADDR *pcptr)
 
 static struct target_ops linux_target_ops = {
   linux_create_inferior,
-  linux_arch_setup,
+  linux_post_create_inferior,
   linux_attach,
   linux_kill,
   linux_detach,

gdb/gdbserver/lynx-low.c

@@ -722,7 +722,7 @@ lynx_request_interrupt (void)
 
 static struct target_ops lynx_target_ops = {
   lynx_create_inferior,
-  NULL,  /* arch_setup */
+  NULL,  /* post_create_inferior */
   lynx_attach,
   lynx_kill,
   lynx_detach,

gdb/gdbserver/nto-low.c

@@ -933,7 +933,7 @@ nto_sw_breakpoint_from_kind (int kind, int *size)
 
 static struct target_ops nto_target_ops = {
   nto_create_inferior,
-  NULL,  /* arch_setup */
+  NULL,  /* post_create_inferior */
   nto_attach,
   nto_kill,
   nto_detach,

gdb/gdbserver/server.c

@@ -282,7 +282,7 @@ start_inferior (char **argv)
 	    }
 	  while (last_status.value.sig != GDB_SIGNAL_TRAP);
 	}
-      target_arch_setup ();
+      target_post_create_inferior ();
       return signal_pid;
     }
 
@@ -290,7 +290,7 @@ start_inferior (char **argv)
      (assuming success).  */
   last_ptid = mywait (pid_to_ptid (signal_pid), &last_status, 0, 0);
 
-  target_arch_setup ();
+  target_post_create_inferior ();
 
   if (last_status.kind != TARGET_WAITKIND_EXITED
       && last_status.kind != TARGET_WAITKIND_SIGNALLED)

gdb/gdbserver/spu-low.c

@@ -653,7 +653,7 @@ spu_sw_breakpoint_from_kind (int kind, int *size)
 
 static struct target_ops spu_target_ops = {
   spu_create_inferior,
-  NULL,  /* arch_setup */
+  NULL,  /* post_create_inferior */
   spu_attach,
   spu_kill,
   spu_detach,

gdb/gdbserver/target.h

@@ -75,8 +75,9 @@ struct target_ops
 
   int (*create_inferior) (char *program, char **args);
 
-  /* Architecture-specific setup.  */
-  void (*arch_setup) (void);
+  /* Do additional setup after a new process is created, including
+     exec-wrapper completion.  */
+  void (*post_create_inferior) (void);
 
   /* Attach to a running process.
 
@@ -475,11 +476,11 @@ void set_target_ops (struct target_ops *);
 #define create_inferior(program, args) \
   (*the_target->create_inferior) (program, args)
 
-#define target_arch_setup()			 \
+#define target_post_create_inferior()			 \
   do							 \
     {							 \
-      if (the_target->arch_setup != NULL)	 \
-	(*the_target->arch_setup) ();		 \
+      if (the_target->post_create_inferior != NULL)	 \
+	(*the_target->post_create_inferior) ();		 \
     } while (0)
 
 #define myattach(pid) \

gdb/gdbserver/win32-low.c

@@ -1794,7 +1794,7 @@ win32_sw_breakpoint_from_kind (int kind, int *size)
 
 static struct target_ops win32_target_ops = {
   win32_create_inferior,
-  NULL,  /* arch_setup */
+  NULL,  /* post_create_inferior */
   win32_attach,
   win32_kill,
   win32_detach,

gdb/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2015-12-04  Josh Stone  <jistone@redhat.com>
+
+	* gdb.base/catch-fork-static.exp: New.
+
 2015-12-03  Yao Qi  <yao.qi@linaro.org>
 
 	* gdb.base/sizeof.c: Don't include stdio.h and

gdb/testsuite/gdb.base/catch-fork-static.exp

@@ -0,0 +1,48 @@
+# Copyright (C) 2015 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Test that "catch fork" works on static executables.
+
+# For instance, on Linux we need PTRACE_O_TRACEFORK set before the program
+# reaches the fork.  GDBserver was only setting flags when it reached the first
+# stop *after* arch_setup.  In a dynamic executable there is often a swbreak in
+# ld.so probes before reaching main, and ptrace flags were set then.  But a
+# static executable would just keep running and never catch the fork.
+
+if { [is_remote target] || ![isnative] } then {
+    continue
+}
+
+# Until "catch fork" is implemented on other targets...
+#
+if { ![istarget "hppa*-hp-hpux*"] && ![istarget "*-*-linux*"]
+     && ![istarget "*-*-openbsd*"] } then {
+    continue
+}
+
+# Reusing foll-fork.c since it's a simple forking program.
+standard_testfile foll-fork.c
+
+if { [prepare_for_testing ${testfile}.exp ${testfile} $srcfile \
+      {additional_flags=-static}] } {
+    return -1
+}
+
+gdb_test "catch fork" "Catchpoint \[0-9\]* \\(fork\\)"
+
+gdb_run_cmd
+gdb_test "" \
+    "Catchpoint \[0-9\]* \\(forked process \[0-9\]*\\),.*" \
+    "run to fork"