gdb/gdbserver/target.c - binutils-gdb - Git at Google

 /* Target operations for the remote server for GDB.
    Copyright (C) 2002-2020 Free Software Foundation, Inc.

    Contributed by MontaVista Software.

    This file is part of GDB.

    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/>.  */

 #include "server.h"
 #include "tracepoint.h"
 #include "gdbsupport/byte-vector.h"

 struct target_ops *the_target;

 int
 set_desired_thread ()
 {
   client_state &cs = get_client_state ();
   thread_info *found = find_thread_ptid (cs.general_thread);

   current_thread = found;
   return (current_thread != NULL);
 }

 /* The thread that was current before prepare_to_access_memory was
    called.  done_accessing_memory uses this to restore the previous
    selected thread.  */
 static ptid_t prev_general_thread;

 /* See target.h.  */

 int
 prepare_to_access_memory (void)
 {
   client_state &cs = get_client_state ();

   /* The first thread found.  */
   struct thread_info *first = NULL;
   /* The first stopped thread found.  */
   struct thread_info *stopped = NULL;
   /* The current general thread, if found.  */
   struct thread_info *current = NULL;

   /* Save the general thread value, since prepare_to_access_memory could change
      it.  */
   prev_general_thread = cs.general_thread;

   if (the_target->prepare_to_access_memory != NULL)
     {
       int res;

       res = the_target->prepare_to_access_memory ();
       if (res != 0)
 	return res;
     }

   for_each_thread (prev_general_thread.pid (), [&] (thread_info *thread)
     {
       if (mythread_alive (thread->id))
 	{
 	  if (stopped == NULL && the_target->thread_stopped != NULL
 	      && thread_stopped (thread))
 	    stopped = thread;

 	  if (first == NULL)
 	    first = thread;

 	  if (current == NULL && prev_general_thread == thread->id)
 	    current = thread;
 	}
     });

   /* The thread we end up choosing.  */
   struct thread_info *thread;

   /* Prefer a stopped thread.  If none is found, try the current
      thread.  Otherwise, take the first thread in the process.  If
      none is found, undo the effects of
      target->prepare_to_access_memory() and return error.  */
   if (stopped != NULL)
     thread = stopped;
   else if (current != NULL)
     thread = current;
   else if (first != NULL)
     thread = first;
   else
     {
       done_accessing_memory ();
       return 1;
     }

   current_thread = thread;
   cs.general_thread = ptid_of (thread);

   return 0;
 }

 /* See target.h.  */

 void
 done_accessing_memory (void)
 {
   client_state &cs = get_client_state ();

   if (the_target->done_accessing_memory != NULL)
     the_target->done_accessing_memory ();

   /* Restore the previous selected thread.  */
   cs.general_thread = prev_general_thread;
   switch_to_thread (cs.general_thread);
 }

 int
 read_inferior_memory (CORE_ADDR memaddr, unsigned char *myaddr, int len)
 {
   int res;
   res = (*the_target->read_memory) (memaddr, myaddr, len);
   check_mem_read (memaddr, myaddr, len);
   return res;
 }

 /* See target/target.h.  */

 int
 target_read_memory (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 {
   return read_inferior_memory (memaddr, myaddr, len);
 }

 /* See target/target.h.  */

 int
 target_read_uint32 (CORE_ADDR memaddr, uint32_t *result)
 {
   return read_inferior_memory (memaddr, (gdb_byte *) result, sizeof (*result));
 }

 /* See target/target.h.  */

 int
 target_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr,
 		     ssize_t len)
 {
   /* Make a copy of the data because check_mem_write may need to
      update it.  */
   gdb::byte_vector buffer (myaddr, myaddr + len);
   check_mem_write (memaddr, buffer.data (), myaddr, len);
   return (*the_target->write_memory) (memaddr, buffer.data (), len);
 }

 ptid_t
 mywait (ptid_t ptid, struct target_waitstatus *ourstatus, int options,
 	int connected_wait)
 {
   ptid_t ret;

   if (connected_wait)
     server_waiting = 1;

   ret = target_wait (ptid, ourstatus, options);

   /* We don't expose _LOADED events to gdbserver core.  See the
      `dlls_changed' global.  */
   if (ourstatus->kind == TARGET_WAITKIND_LOADED)
     ourstatus->kind = TARGET_WAITKIND_STOPPED;

   /* If GDB is connected through TCP/serial, then GDBserver will most
      probably be running on its own terminal/console, so it's nice to
      print there why is GDBserver exiting.  If however, GDB is
      connected through stdio, then there's no need to spam the GDB
      console with this -- the user will already see the exit through
      regular GDB output, in that same terminal.  */
   if (!remote_connection_is_stdio ())
     {
       if (ourstatus->kind == TARGET_WAITKIND_EXITED)
 	fprintf (stderr,
 		 "\nChild exited with status %d\n", ourstatus->value.integer);
       else if (ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
 	fprintf (stderr, "\nChild terminated with signal = 0x%x (%s)\n",
 		 gdb_signal_to_host (ourstatus->value.sig),
 		 gdb_signal_to_name (ourstatus->value.sig));
     }

   if (connected_wait)
     server_waiting = 0;

   return ret;
 }

 /* See target/target.h.  */

 void
 target_stop_and_wait (ptid_t ptid)
 {
   struct target_waitstatus status;
   bool was_non_stop = non_stop;
   struct thread_resume resume_info;

   resume_info.thread = ptid;
   resume_info.kind = resume_stop;
   resume_info.sig = GDB_SIGNAL_0;
   (*the_target->resume) (&resume_info, 1);

   non_stop = true;
   mywait (ptid, &status, 0, 0);
   non_stop = was_non_stop;
 }

 /* See target/target.h.  */

 ptid_t
 target_wait (ptid_t ptid, struct target_waitstatus *status, int options)
 {
   return (*the_target->wait) (ptid, status, options);
 }

 /* See target/target.h.  */

 void
 target_mourn_inferior (ptid_t ptid)
 {
   (*the_target->mourn) (find_process_pid (ptid.pid ()));
 }

 /* See target/target.h.  */

 void
 target_continue_no_signal (ptid_t ptid)
 {
   struct thread_resume resume_info;

   resume_info.thread = ptid;
   resume_info.kind = resume_continue;
   resume_info.sig = GDB_SIGNAL_0;
   (*the_target->resume) (&resume_info, 1);
 }

 /* See target/target.h.  */

 void
 target_continue (ptid_t ptid, enum gdb_signal signal)
 {
   struct thread_resume resume_info;

   resume_info.thread = ptid;
   resume_info.kind = resume_continue;
   resume_info.sig = gdb_signal_to_host (signal);
   (*the_target->resume) (&resume_info, 1);
 }

 /* See target/target.h.  */

 int
 target_supports_multi_process (void)
 {
   return (the_target->supports_multi_process != NULL ?
 	  (*the_target->supports_multi_process) () : 0);
 }

 int
 start_non_stop (int nonstop)
 {
   if (the_target->start_non_stop == NULL)
     {
       if (nonstop)
 	return -1;
       else
 	return 0;
     }

   return (*the_target->start_non_stop) (nonstop);
 }

 void
 set_target_ops (struct target_ops *target)
 {
   the_target = XNEW (struct target_ops);
   memcpy (the_target, target, sizeof (*the_target));
 }

 /* Convert pid to printable format.  */

 const char *
 target_pid_to_str (ptid_t ptid)
 {
   static char buf[80];

   if (ptid == minus_one_ptid)
     xsnprintf (buf, sizeof (buf), "<all threads>");
   else if (ptid == null_ptid)
     xsnprintf (buf, sizeof (buf), "<null thread>");
   else if (ptid.tid () != 0)
     xsnprintf (buf, sizeof (buf), "Thread %d.0x%lx",
 	       ptid.pid (), ptid.tid ());
   else if (ptid.lwp () != 0)
     xsnprintf (buf, sizeof (buf), "LWP %d.%ld",
 	       ptid.pid (), ptid.lwp ());
   else
     xsnprintf (buf, sizeof (buf), "Process %d",
 	       ptid.pid ());

   return buf;
 }

 int
 kill_inferior (process_info *proc)
 {
   gdb_agent_about_to_close (proc->pid);

   return (*the_target->kill) (proc);
 }

 /* Target can do hardware single step.  */

 int
 target_can_do_hardware_single_step (void)
 {
   return 1;
 }

 /* Default implementation for breakpoint_kind_for_pc.

    The default behavior for targets that don't implement breakpoint_kind_for_pc
    is to use the size of a breakpoint as the kind.  */

 int
 default_breakpoint_kind_from_pc (CORE_ADDR *pcptr)
 {
   int size = 0;

   gdb_assert (the_target->sw_breakpoint_from_kind != NULL);

   (*the_target->sw_breakpoint_from_kind) (0, &size);
   return size;
 }

 /* Define it.  */

 target_terminal_state target_terminal::m_terminal_state
   = target_terminal_state::is_ours;

 /* See target/target.h.  */

 void
 target_terminal::init ()
 {
   /* Placeholder needed because of fork_inferior.  Not necessary on
      GDBserver.  */
 }

 /* See target/target.h.  */

 void
 target_terminal::inferior ()
 {
   /* Placeholder needed because of fork_inferior.  Not necessary on
      GDBserver.  */
 }

 /* See target/target.h.  */

 void
 target_terminal::ours ()
 {
   /* Placeholder needed because of fork_inferior.  Not necessary on
      GDBserver.  */
 }

 /* See target/target.h.  */

 void
 target_terminal::ours_for_output (void)
 {
   /* Placeholder.  */
 }

 /* See target/target.h.  */

 void
 target_terminal::info (const char *arg, int from_tty)
 {
   /* Placeholder.  */
 }
	/* Target operations for the remote server for GDB.
	Copyright (C) 2002-2020 Free Software Foundation, Inc.

	Contributed by MontaVista Software.

	This file is part of GDB.

	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/>. */

	#include "server.h"
	#include "tracepoint.h"
	#include "gdbsupport/byte-vector.h"

	struct target_ops *the_target;

	int
	set_desired_thread ()
	{
	client_state &cs = get_client_state ();
	thread_info *found = find_thread_ptid (cs.general_thread);

	current_thread = found;
	return (current_thread != NULL);
	}

	/* The thread that was current before prepare_to_access_memory was
	called. done_accessing_memory uses this to restore the previous
	selected thread. */
	static ptid_t prev_general_thread;

	/* See target.h. */

	int
	prepare_to_access_memory (void)
	{
	client_state &cs = get_client_state ();

	/* The first thread found. */
	struct thread_info *first = NULL;
	/* The first stopped thread found. */
	struct thread_info *stopped = NULL;
	/* The current general thread, if found. */
	struct thread_info *current = NULL;

	/* Save the general thread value, since prepare_to_access_memory could change
	it. */
	prev_general_thread = cs.general_thread;

	if (the_target->prepare_to_access_memory != NULL)
	{
	int res;

	res = the_target->prepare_to_access_memory ();
	if (res != 0)
	return res;
	}

	for_each_thread (prev_general_thread.pid (), [&] (thread_info *thread)
	{
	if (mythread_alive (thread->id))
	{
	if (stopped == NULL && the_target->thread_stopped != NULL
	&& thread_stopped (thread))
	stopped = thread;

	if (first == NULL)
	first = thread;

	if (current == NULL && prev_general_thread == thread->id)
	current = thread;
	}
	});

	/* The thread we end up choosing. */
	struct thread_info *thread;

	/* Prefer a stopped thread. If none is found, try the current
	thread. Otherwise, take the first thread in the process. If
	none is found, undo the effects of
	target->prepare_to_access_memory() and return error. */
	if (stopped != NULL)
	thread = stopped;
	else if (current != NULL)
	thread = current;
	else if (first != NULL)
	thread = first;
	else
	{
	done_accessing_memory ();
	return 1;
	}

	current_thread = thread;
	cs.general_thread = ptid_of (thread);

	return 0;
	}

	/* See target.h. */

	void
	done_accessing_memory (void)
	{
	client_state &cs = get_client_state ();

	if (the_target->done_accessing_memory != NULL)
	the_target->done_accessing_memory ();

	/* Restore the previous selected thread. */
	cs.general_thread = prev_general_thread;
	switch_to_thread (cs.general_thread);
	}

	int
	read_inferior_memory (CORE_ADDR memaddr, unsigned char *myaddr, int len)
	{
	int res;
	res = (*the_target->read_memory) (memaddr, myaddr, len);
	check_mem_read (memaddr, myaddr, len);
	return res;
	}

	/* See target/target.h. */

	int
	target_read_memory (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
	{
	return read_inferior_memory (memaddr, myaddr, len);
	}

	/* See target/target.h. */

	int
	target_read_uint32 (CORE_ADDR memaddr, uint32_t *result)
	{
	return read_inferior_memory (memaddr, (gdb_byte ) result, sizeof (result));
	}

	/* See target/target.h. */

	int
	target_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr,
	ssize_t len)
	{
	/* Make a copy of the data because check_mem_write may need to
	update it. */
	gdb::byte_vector buffer (myaddr, myaddr + len);
	check_mem_write (memaddr, buffer.data (), myaddr, len);
	return (*the_target->write_memory) (memaddr, buffer.data (), len);
	}

	ptid_t
	mywait (ptid_t ptid, struct target_waitstatus *ourstatus, int options,
	int connected_wait)
	{
	ptid_t ret;

	if (connected_wait)
	server_waiting = 1;

	ret = target_wait (ptid, ourstatus, options);

	/* We don't expose _LOADED events to gdbserver core. See the
	`dlls_changed' global. */
	if (ourstatus->kind == TARGET_WAITKIND_LOADED)
	ourstatus->kind = TARGET_WAITKIND_STOPPED;

	/* If GDB is connected through TCP/serial, then GDBserver will most
	probably be running on its own terminal/console, so it's nice to
	print there why is GDBserver exiting. If however, GDB is
	connected through stdio, then there's no need to spam the GDB
	console with this -- the user will already see the exit through
	regular GDB output, in that same terminal. */
	if (!remote_connection_is_stdio ())
	{
	if (ourstatus->kind == TARGET_WAITKIND_EXITED)
	fprintf (stderr,
	"\nChild exited with status %d\n", ourstatus->value.integer);
	else if (ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
	fprintf (stderr, "\nChild terminated with signal = 0x%x (%s)\n",
	gdb_signal_to_host (ourstatus->value.sig),
	gdb_signal_to_name (ourstatus->value.sig));
	}

	if (connected_wait)
	server_waiting = 0;

	return ret;
	}

	/* See target/target.h. */

	void
	target_stop_and_wait (ptid_t ptid)
	{
	struct target_waitstatus status;
	bool was_non_stop = non_stop;
	struct thread_resume resume_info;

	resume_info.thread = ptid;
	resume_info.kind = resume_stop;
	resume_info.sig = GDB_SIGNAL_0;
	(*the_target->resume) (&resume_info, 1);

	non_stop = true;
	mywait (ptid, &status, 0, 0);
	non_stop = was_non_stop;
	}

	/* See target/target.h. */

	ptid_t
	target_wait (ptid_t ptid, struct target_waitstatus *status, int options)
	{
	return (*the_target->wait) (ptid, status, options);
	}

	/* See target/target.h. */

	void
	target_mourn_inferior (ptid_t ptid)
	{
	(*the_target->mourn) (find_process_pid (ptid.pid ()));
	}

	/* See target/target.h. */

	void
	target_continue_no_signal (ptid_t ptid)
	{
	struct thread_resume resume_info;

	resume_info.thread = ptid;
	resume_info.kind = resume_continue;
	resume_info.sig = GDB_SIGNAL_0;
	(*the_target->resume) (&resume_info, 1);
	}

	/* See target/target.h. */

	void
	target_continue (ptid_t ptid, enum gdb_signal signal)
	{
	struct thread_resume resume_info;

	resume_info.thread = ptid;
	resume_info.kind = resume_continue;
	resume_info.sig = gdb_signal_to_host (signal);
	(*the_target->resume) (&resume_info, 1);
	}

	/* See target/target.h. */

	int
	target_supports_multi_process (void)
	{
	return (the_target->supports_multi_process != NULL ?
	(*the_target->supports_multi_process) () : 0);
	}

	int
	start_non_stop (int nonstop)
	{
	if (the_target->start_non_stop == NULL)
	{
	if (nonstop)
	return -1;
	else
	return 0;
	}

	return (*the_target->start_non_stop) (nonstop);
	}

	void
	set_target_ops (struct target_ops *target)
	{
	the_target = XNEW (struct target_ops);
	memcpy (the_target, target, sizeof (*the_target));
	}

	/* Convert pid to printable format. */

	const char *
	target_pid_to_str (ptid_t ptid)
	{
	static char buf[80];

	if (ptid == minus_one_ptid)
	xsnprintf (buf, sizeof (buf), "<all threads>");
	else if (ptid == null_ptid)
	xsnprintf (buf, sizeof (buf), "<null thread>");
	else if (ptid.tid () != 0)
	xsnprintf (buf, sizeof (buf), "Thread %d.0x%lx",
	ptid.pid (), ptid.tid ());
	else if (ptid.lwp () != 0)
	xsnprintf (buf, sizeof (buf), "LWP %d.%ld",
	ptid.pid (), ptid.lwp ());
	else
	xsnprintf (buf, sizeof (buf), "Process %d",
	ptid.pid ());

	return buf;
	}

	int
	kill_inferior (process_info *proc)
	{
	gdb_agent_about_to_close (proc->pid);

	return (*the_target->kill) (proc);
	}

	/* Target can do hardware single step. */

	int
	target_can_do_hardware_single_step (void)
	{
	return 1;
	}

	/* Default implementation for breakpoint_kind_for_pc.

	The default behavior for targets that don't implement breakpoint_kind_for_pc
	is to use the size of a breakpoint as the kind. */

	int
	default_breakpoint_kind_from_pc (CORE_ADDR *pcptr)
	{
	int size = 0;

	gdb_assert (the_target->sw_breakpoint_from_kind != NULL);

	(*the_target->sw_breakpoint_from_kind) (0, &size);
	return size;
	}

	/* Define it. */

	target_terminal_state target_terminal::m_terminal_state
	= target_terminal_state::is_ours;

	/* See target/target.h. */

	void
	target_terminal::init ()
	{
	/* Placeholder needed because of fork_inferior. Not necessary on
	GDBserver. */
	}

	/* See target/target.h. */

	void
	target_terminal::inferior ()
	{
	/* Placeholder needed because of fork_inferior. Not necessary on
	GDBserver. */
	}

	/* See target/target.h. */

	void
	target_terminal::ours ()
	{
	/* Placeholder needed because of fork_inferior. Not necessary on
	GDBserver. */
	}

	/* See target/target.h. */

	void
	target_terminal::ours_for_output (void)
	{
	/* Placeholder. */
	}

	/* See target/target.h. */

	void
	target_terminal::info (const char *arg, int from_tty)
	{
	/* Placeholder. */
	}