old-cross-binutils/gdb/gdbserver/server.h
Don Breazeal 94585166df Extended-remote follow-exec
This patch implements support for exec events on extended-remote Linux
targets.  Follow-exec-mode and rerun behave as expected.  Catchpoints and
test updates are implemented in subsequent patches.

This patch was derived from a patch posted last October:
https://sourceware.org/ml/gdb-patches/2014-10/msg00877.html.
It was originally based on some work done by Luis Machado in 2013.

IMPLEMENTATION
----------------
Exec events are enabled via ptrace options.

When an exec event is detected by gdbserver, the existing process
data, along with all its associated lwp and thread data, is deleted
and replaced by data for a new single-threaded process.  The new
process data is initialized with the appropriate parts of the state
of the execing process.  This approach takes care of several potential
pitfalls, including:

 * deleting the data for an execing non-leader thread before any
   wait/sigsuspend occurs
 * correctly initializing the architecture of the execed process

We then report the exec event using a new RSP stop reason, "exec".

When GDB receives an "exec" event, it saves the status in the event
structure's target_waitstatus field, like what is done for remote fork
events.  Because the original and execed programs may have different
architectures, we skip parsing the section of the stop reply packet
that contains register data.  The register data will be retrieved
later after the inferior's architecture has been set up by
infrun.c:follow_exec.

At that point the exec event is handled by the existing event handling
in GDB.  However, a few changes were necessary so that
infrun.c:follow_exec could accommodate the remote target.

 * Where follow-exec-mode "new" is handled, we now call
   add_inferior_with_spaces instead of add_inferior with separate calls
   to set up the program and address spaces.  The motivation for this
   is that add_inferior_with_spaces also sets up the initial architecture
   for the inferior, which is needed later by target_find_description
   when it calls target_gdbarch.

 * We call a new target function, target_follow_exec.  This function
   allows us to store the execd_pathname in the inferior, instead of
   using the static string remote_exec_file from remote.c.  The static
   string didn't work for follow-exec-mode "new", since once you switched
   to the execed program, the original remote exec-file was lost.  The
   execd_pathname is now stored in the inferior's program space as a
   REGISTRY field.  All of the requisite mechanisms for this are
   defined in remote.c.

gdb/gdbserver/ChangeLog:

	* linux-low.c (linux_mourn): Static declaration.
	(linux_arch_setup): Move in front of
	handle_extended_wait.
	(linux_arch_setup_thread): New function.
	(handle_extended_wait): Handle exec events.  Call
	linux_arch_setup_thread.  Make event_lwp argument a
	pointer-to-a-pointer.
	(check_zombie_leaders): Do not check stopped threads.
	(linux_low_ptrace_options): Add PTRACE_O_TRACEEXEC.
	(linux_low_filter_event): Add lwp and thread for exec'ing
	non-leader thread if leader thread has been deleted.
	Refactor code into linux_arch_setup_thread and call it.
	Pass child lwp pointer by reference to handle_extended_wait.
	(linux_wait_for_event_filtered): Update comment.
	(linux_wait_1): Prevent clobbering exec event status.
	(linux_supports_exec_events): New function.
	(linux_target_ops) <supports_exec_events>: Initialize new member.
	* lynx-low.c (lynx_target_ops) <supports_exec_events>: Initialize
	new member.
	* remote-utils.c (prepare_resume_reply): New stop reason 'exec'.
	* server.c (report_exec_events): New global variable.
	(handle_query): Handle qSupported query for exec-events feature.
	(captured_main): Initialize report_exec_events.
	* server.h (report_exec_events): Declare new global variable.
	* target.h (struct target_ops) <supports_exec_events>: New
	member.
	(target_supports_exec_events): New macro.
	* win32-low.c (win32_target_ops) <supports_exec_events>:
	Initialize new member.

gdb/ChangeLog:

	* infrun.c (follow_exec): Use process-style ptid for
	exec message.  Call add_inferior_with_spaces and
	target_follow_exec.
	* nat/linux-ptrace.c (linux_supports_traceexec): New function.
	* nat/linux-ptrace.h (linux_supports_traceexec): Declare.
	* remote.c (remote_pspace_data): New static variable.
	(remote_pspace_data_cleanup): New function.
	(get_remote_exec_file): New function.
	(set_remote_exec_file_1): New function.
	(set_remote_exec_file): New function.
	(show_remote_exec_file): New function.
	(remote_exec_file): Delete static variable.
	(anonymous enum) <PACKET_exec_event_feature> New
	enumeration constant.
	(remote_protocol_features): Add entry for exec-events feature.
	(remote_query_supported): Add client side of qSupported query
	for exec-events feature.
	(remote_follow_exec): New function.
	(remote_parse_stop_reply): Handle 'exec' stop reason.
	(extended_remote_run, extended_remote_create_inferior): Call
	get_remote_exec_file and set_remote_exec_file_1.
	(init_extended_remote_ops) <to_follow_exec>: Initialize new
	member.
	(_initialize_remote): Call
	register_program_space_data_with_cleanup.  Call
	add_packet_config_cmd for remote exec-events feature.
	Modify call to add_setshow_string_noescape_cmd for exec-file
	to use new functions set_remote_exec_file and
	show_remote_exec_file.
	* target-debug.h, target-delegates.c: Regenerated.
	* target.c (target_follow_exec): New function.
	* target.h (struct target_ops) <to_follow_exec>: New member.
	(target_follow_exec): Declare new function.
2015-09-11 11:12:46 -07:00

136 lines
3.6 KiB
C

/* Common definitions for remote server for GDB.
Copyright (C) 1993-2015 Free Software Foundation, Inc.
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/>. */
#ifndef SERVER_H
#define SERVER_H
#include "common-defs.h"
gdb_static_assert (sizeof (CORE_ADDR) >= sizeof (void *));
#ifdef __MINGW32CE__
#include "wincecompat.h"
#endif
#include "version.h"
#if !HAVE_DECL_STRERROR
#ifndef strerror
extern char *strerror (int); /* X3.159-1989 4.11.6.2 */
#endif
#endif
#if !HAVE_DECL_PERROR
#ifndef perror
extern void perror (const char *);
#endif
#endif
#if !HAVE_DECL_VASPRINTF
extern int vasprintf(char **strp, const char *fmt, va_list ap);
#endif
#if !HAVE_DECL_VSNPRINTF
int vsnprintf(char *str, size_t size, const char *format, va_list ap);
#endif
#ifdef IN_PROCESS_AGENT
# define PROG "ipa"
#else
# define PROG "gdbserver"
#endif
#include "buffer.h"
#include "xml-utils.h"
#include "regcache.h"
#include "gdb_signals.h"
#include "target.h"
#include "mem-break.h"
#include "gdbthread.h"
#include "inferiors.h"
/* Target-specific functions */
void initialize_low ();
/* Public variables in server.c */
extern ptid_t cont_thread;
extern ptid_t general_thread;
extern int server_waiting;
extern int pass_signals[];
extern int program_signals[];
extern int program_signals_p;
extern int disable_packet_vCont;
extern int disable_packet_Tthread;
extern int disable_packet_qC;
extern int disable_packet_qfThreadInfo;
extern int run_once;
extern int multi_process;
extern int report_fork_events;
extern int report_vfork_events;
extern int report_exec_events;
extern int non_stop;
extern int extended_protocol;
/* True if the "swbreak+" feature is active. In that case, GDB wants
us to report whether a trap is explained by a software breakpoint
and for the server to handle PC adjustment if necessary on this
target. Only enabled if the target supports it. */
extern int swbreak_feature;
/* True if the "hwbreak+" feature is active. In that case, GDB wants
us to report whether a trap is explained by a hardware breakpoint.
Only enabled if the target supports it. */
extern int hwbreak_feature;
extern int disable_randomization;
#if USE_WIN32API
#include <winsock2.h>
typedef SOCKET gdb_fildes_t;
#else
typedef int gdb_fildes_t;
#endif
#include "event-loop.h"
/* Functions from server.c. */
extern int handle_serial_event (int err, gdb_client_data client_data);
extern int handle_target_event (int err, gdb_client_data client_data);
/* Get rid of the currently pending stop replies that match PTID. */
extern void discard_queued_stop_replies (ptid_t ptid);
#include "remote-utils.h"
#include "utils.h"
#include "debug.h"
/* Maximum number of bytes to read/write at once. The value here
is chosen to fill up a packet (the headers account for the 32). */
#define MAXBUFBYTES(N) (((N)-32)/2)
/* Buffer sizes for transferring memory, registers, etc. Set to a constant
value to accomodate multiple register formats. This value must be at least
as large as the largest register set supported by gdbserver. */
#define PBUFSIZ 16384
#endif /* SERVER_H */