From patchwork Thu Mar 26 19:00:32 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Don Breazeal X-Patchwork-Id: 5834 Received: (qmail 36551 invoked by alias); 26 Mar 2015 19:00:41 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 36526 invoked by uid 89); 26 Mar 2015 19:00:40 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.1 required=5.0 tests=AWL, BAYES_00, RCVD_IN_DNSWL_LOW, SPF_PASS autolearn=ham version=3.3.2 X-HELO: relay1.mentorg.com Received: from relay1.mentorg.com (HELO relay1.mentorg.com) (192.94.38.131) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Thu, 26 Mar 2015 19:00:36 +0000 Received: from svr-orw-fem-03.mgc.mentorg.com ([147.34.97.39]) by relay1.mentorg.com with esmtp id 1YbD16-00012b-Ob from Don_Breazeal@mentor.com ; Thu, 26 Mar 2015 12:00:32 -0700 Received: from build4-lucid-cs (147.34.91.1) by svr-orw-fem-03.mgc.mentorg.com (147.34.97.39) with Microsoft SMTP Server id 14.3.224.2; Thu, 26 Mar 2015 12:00:32 -0700 Received: by build4-lucid-cs (Postfix, from userid 1905) id 24AEE40F0D; Thu, 26 Mar 2015 12:00:31 -0700 (PDT) From: Don Breazeal To: , Subject: Re: [PATCH v5 01/06] Identify remote fork event support Date: Thu, 26 Mar 2015 12:00:32 -0700 Message-ID: <1427396432-4670-1-git-send-email-donb@codesourcery.com> In-Reply-To: <5511430E.7040608@redhat.com> MIME-Version: 1.0 X-IsSubscribed: yes On 3/24/2015 3:57 AM, Pedro Alves wrote: > On 03/17/2015 08:56 PM, Don Breazeal wrote: > >> @@ -12508,7 +12524,8 @@ Show the maximum size of the address (in bits) in a memory packet."), NULL, >> add_packet_config_cmd (&remote_protocol_packets[PACKET_hwbreak_feature], >> "hwbreak-feature", "hwbreak-feature", 0); >> >> - /* Assert that we've registered commands for all packet configs. */ >> + /* Assert that we've registered "set remote foo-packet" commands >> + for all packet configs. */ >> { >> int i; >> > > This hunk could go immediately/separately as obvious. Thanks, this has been pushed. >> @@ -12527,6 +12544,8 @@ Show the maximum size of the address (in bits) in a memory packet."), NULL, >> case PACKET_DisconnectedTracing_feature: >> case PACKET_augmented_libraries_svr4_read_feature: >> case PACKET_qCRC: >> + case PACKET_fork_event_feature: >> + case PACKET_vfork_event_feature: >> /* Additions to this list need to be well justified: >> pre-existing packets are OK; new packets are not. */ > > I think I mentioned this before: please do register commands for these > features. As the comment says, new packets here are not OK without > good justification, and I can't think of a good justification. > Then you'll need to make sure remote_query_supported only includes the > feature in GDB's query if the feature wasn't force-disabled. See > the new swbreak+ feature's handling in that function. You did mention this before, but I misunderstood. I've made the updates in this version. Sorry for the repeat. Thanks --Don This patch implements a mechanism for GDB to determine whether fork events are supported in gdbserver. This is a preparatory patch for remote fork and exec event support. Two new RSP packets are defined to represent fork and vfork event support. These packets are used similar to PACKET_swbreak_feature to denote whether the corresponding event is supported. GDB sends fork-events+ and vfork-events+ to gdbserver to inquire about fork event support. If the response enables these packets, then GDB knows that gdbserver supports the corresponding events and will enable them. Gdbserver target functions used to query for support are included, corresponding to each new packet. In order for gdbserver to know whether the events are supported at the point where the qSupported packet arrives, the code in nat/linux-ptrace.c had to be reorganized. Previously it would test for fork/exec event support, then enable the events using the pid of the inferior. When the qSupported packet arrives there may not be an inferior. So the mechanism was split into two parts: a function that checks whether the events are supported, called when gdbserver starts up, and another that enables the events when the inferior stops for the first time. Another gdbserver change was to add some global variables similar to multi_process, one per new packet. These are used to control whether the corresponding fork events are enabled. If GDB does not inquire about the event support in the qSupported packet, then gdbserver will not set these "report the event" flags. If the flags are not set, the events are ignored like they were in the past. Thus, gdbserver will never send fork event notification to an older GDB that doesn't recognize fork events. Tested on Ubuntu x64, native/remote/extended-remote, and as part of subsequent patches in the series. gdb/doc/ 2015-03-26 Don Breazeal * gdb.texinfo (General Query Packets): Add remote protocol features 'fork-events' and 'vfork-events'. gdb/gdbserver/ 2015-03-26 Don Breazeal * linux-low.c (linux_supports_fork_events): New function. (linux_supports_vfork_events): New function. (linux_target_ops): Initialize new structure members. (initialize_low): Call linux_check_ptrace_features. * lynx-low.c (lynx_target_ops): Initialize new structure members. * server.c (report_fork_events, report_vfork_events): New global flags. (handle_query): Add new features to qSupported packet. (captured_main): Initialize new global variables. * target.h (struct target_ops) : New member. : New member. (target_supports_fork_events): New macro. (target_supports_vfork_events): New macro. * win32-low.c (win32_target_ops): Initialize new structure members. gdb/ 2015-03-26 Don Breazeal * NEWS: Announce new fork event feature support in qSupported packet. * nat/linux-ptrace.c (linux_check_ptrace_features): Change from static to extern. * nat/linux-ptrace.h (linux_check_ptrace_features): Declare. * remote.c (anonymous enum): : New enumeration constants. (remote_query_supported): Add new feature queries to qSupported packet. (remote_protocol_features): Add table entries for new packets. (_initialize_remote): Implement 'set remote foo-packet' commands for new packets. --- gdb/NEWS | 3 +++ gdb/doc/gdb.texinfo | 12 ++++++++++++ gdb/gdbserver/linux-low.c | 21 +++++++++++++++++++++ gdb/gdbserver/lynx-low.c | 2 ++ gdb/gdbserver/server.c | 22 ++++++++++++++++++++++ gdb/gdbserver/target.h | 14 ++++++++++++++ gdb/gdbserver/win32-low.c | 2 ++ gdb/nat/linux-ptrace.c | 2 +- gdb/nat/linux-ptrace.h | 1 + gdb/remote.c | 26 ++++++++++++++++++++++++++ 10 files changed, 104 insertions(+), 1 deletion(-) diff --git a/gdb/NEWS b/gdb/NEWS index 3fa33c9..1d24b3b 100644 --- a/gdb/NEWS +++ b/gdb/NEWS @@ -96,6 +96,9 @@ vFile:fstat: HP/PA running HP-UX hppa*-*-hpux* Itanium running HP-UX ia64-*-hpux* +* The remote stub now reports support for fork and vfork events to GDB's +qSupported query. + *** Changes in GDB 7.9 * GDB now supports hardware watchpoints on x86 GNU Hurd. diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo index c03ecb0..a1d312e 100644 --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -35812,6 +35812,18 @@ extensions unless the stub also reports that it supports them by including @samp{multiprocess+} in its @samp{qSupported} reply. @xref{multiprocess extensions}, for details. +@item fork-events +This feature indicates whether @value{GDBN} supports fork event +extensions to the remote protocol. @value{GDBN} does not use such +extensions unless the stub also reports that it supports them by +including @samp{fork-events+} in its @samp{qSupported} reply. + +@item vfork-events +This feature indicates whether @value{GDBN} supports vfork event +extensions to the remote protocol. @value{GDBN} does not use such +extensions unless the stub also reports that it supports them by +including @samp{vfork-events+} in its @samp{qSupported} reply. + @item xmlRegisters This feature indicates that @value{GDBN} supports the XML target description. If the stub sees @samp{xmlRegisters=} with target diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c index e4c5420..06ac673 100644 --- a/gdb/gdbserver/linux-low.c +++ b/gdb/gdbserver/linux-low.c @@ -5421,6 +5421,22 @@ linux_supports_multi_process (void) return 1; } +/* Check if fork events are supported. */ + +static int +linux_supports_fork_events (void) +{ + return linux_supports_tracefork (); +} + +/* Check if vfork events are supported. */ + +static int +linux_supports_vfork_events (void) +{ + return linux_supports_tracefork (); +} + static int linux_supports_disable_randomization (void) { @@ -6393,6 +6409,8 @@ static struct target_ops linux_target_ops = { linux_async, linux_start_non_stop, linux_supports_multi_process, + linux_supports_fork_events, + linux_supports_vfork_events, #ifdef USE_THREAD_DB thread_db_handle_monitor_command, #else @@ -6469,4 +6487,7 @@ initialize_low (void) sigaction (SIGCHLD, &sigchld_action, NULL); initialize_low_arch (); + + /* Enable extended ptrace events. */ + linux_check_ptrace_features (); } diff --git a/gdb/gdbserver/lynx-low.c b/gdb/gdbserver/lynx-low.c index 2f85829..687cce0 100644 --- a/gdb/gdbserver/lynx-low.c +++ b/gdb/gdbserver/lynx-low.c @@ -758,6 +758,8 @@ static struct target_ops lynx_target_ops = { NULL, /* async */ NULL, /* start_non_stop */ NULL, /* supports_multi_process */ + NULL, /* supports_fork_events */ + NULL, /* supports_vfork_events */ NULL, /* handle_monitor_command */ }; diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c index 96b31b8..dcedea8 100644 --- a/gdb/gdbserver/server.c +++ b/gdb/gdbserver/server.c @@ -57,6 +57,8 @@ static int exit_requested; int run_once; int multi_process; +int report_fork_events; +int report_vfork_events; int non_stop; int swbreak_feature; int hwbreak_feature; @@ -1992,6 +1994,18 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p) if (target_supports_stopped_by_hw_breakpoint ()) hwbreak_feature = 1; } + else if (strcmp (p, "fork-events+") == 0) + { + /* GDB supports and wants fork events if possible. */ + if (target_supports_fork_events ()) + report_fork_events = 1; + } + else if (strcmp (p, "vfork-events+") == 0) + { + /* GDB supports and wants vfork events if possible. */ + if (target_supports_vfork_events ()) + report_vfork_events = 1; + } else target_process_qsupported (p); @@ -2042,6 +2056,12 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p) if (target_supports_multi_process ()) strcat (own_buf, ";multiprocess+"); + if (target_supports_fork_events ()) + strcat (own_buf, ";fork-events+"); + + if (target_supports_vfork_events ()) + strcat (own_buf, ";vfork-events+"); + if (target_supports_non_stop ()) strcat (own_buf, ";QNonStop+"); @@ -3388,6 +3408,8 @@ captured_main (int argc, char *argv[]) noack_mode = 0; multi_process = 0; + report_fork_events = 0; + report_vfork_events = 0; /* Be sure we're out of tfind mode. */ current_traceframe = -1; cont_thread = null_ptid; diff --git a/gdb/gdbserver/target.h b/gdb/gdbserver/target.h index 126c861..dc51627 100644 --- a/gdb/gdbserver/target.h +++ b/gdb/gdbserver/target.h @@ -277,6 +277,12 @@ struct target_ops /* Returns true if the target supports multi-process debugging. */ int (*supports_multi_process) (void); + /* Returns true if fork events are supported. */ + int (*supports_fork_events) (void); + + /* Returns true if vfork events are supported. */ + int (*supports_vfork_events) (void); + /* If not NULL, target-specific routine to process monitor command. Returns 1 if handled, or 0 to perform default processing. */ int (*handle_monitor_command) (char *); @@ -408,6 +414,14 @@ void set_target_ops (struct target_ops *); int kill_inferior (int); +#define target_supports_fork_events() \ + (the_target->supports_fork_events ? \ + (*the_target->supports_fork_events) () : 0) + +#define target_supports_vfork_events() \ + (the_target->supports_vfork_events ? \ + (*the_target->supports_vfork_events) () : 0) + #define detach_inferior(pid) \ (*the_target->detach) (pid) diff --git a/gdb/gdbserver/win32-low.c b/gdb/gdbserver/win32-low.c index 6c86765..5f50e46 100644 --- a/gdb/gdbserver/win32-low.c +++ b/gdb/gdbserver/win32-low.c @@ -1827,6 +1827,8 @@ static struct target_ops win32_target_ops = { NULL, /* async */ NULL, /* start_non_stop */ NULL, /* supports_multi_process */ + NULL, /* supports_fork_events */ + NULL, /* supports_vfork_events */ NULL, /* handle_monitor_command */ NULL, /* core_of_thread */ NULL, /* read_loadmap */ diff --git a/gdb/nat/linux-ptrace.c b/gdb/nat/linux-ptrace.c index 2244d9d..aba3da8 100644 --- a/gdb/nat/linux-ptrace.c +++ b/gdb/nat/linux-ptrace.c @@ -337,7 +337,7 @@ static void linux_test_for_exitkill (int child_pid); /* Determine ptrace features available on this target. */ -static void +void linux_check_ptrace_features (void) { int child_pid, ret, status; diff --git a/gdb/nat/linux-ptrace.h b/gdb/nat/linux-ptrace.h index 8354a4d..03d98c9 100644 --- a/gdb/nat/linux-ptrace.h +++ b/gdb/nat/linux-ptrace.h @@ -149,6 +149,7 @@ extern void linux_ptrace_attach_fail_reason (pid_t pid, struct buffer *buffer); extern char *linux_ptrace_attach_fail_reason_string (ptid_t ptid, int err); extern void linux_ptrace_init_warnings (void); +extern void linux_check_ptrace_features (void); extern void linux_enable_event_reporting (pid_t pid, int attached); extern void linux_disable_event_reporting (pid_t pid); extern int linux_supports_tracefork (void); diff --git a/gdb/remote.c b/gdb/remote.c index 31c933b..95fc0c5 100644 --- a/gdb/remote.c +++ b/gdb/remote.c @@ -1343,6 +1343,12 @@ enum { /* Support for hwbreak+ feature. */ PACKET_hwbreak_feature, + /* Support for fork events. */ + PACKET_fork_event_feature, + + /* Support for vfork events. */ + PACKET_vfork_event_feature, + PACKET_MAX }; @@ -4042,6 +4048,10 @@ static const struct protocol_feature remote_protocol_features[] = { PACKET_Qbtrace_conf_bts_size }, { "swbreak", PACKET_DISABLE, remote_supported_packet, PACKET_swbreak_feature }, { "hwbreak", PACKET_DISABLE, remote_supported_packet, PACKET_hwbreak_feature }, + { "fork-events", PACKET_DISABLE, remote_supported_packet, + PACKET_fork_event_feature }, + { "vfork-events", PACKET_DISABLE, remote_supported_packet, + PACKET_vfork_event_feature }, }; static char *remote_support_xml; @@ -4120,6 +4130,16 @@ remote_query_supported (void) q = remote_query_supported_append (q, "qRelocInsn+"); + if (rs->extended) + { + if (packet_set_cmd_state (PACKET_fork_event_feature) + != AUTO_BOOLEAN_FALSE) + q = remote_query_supported_append (q, "fork-events+"); + if (packet_set_cmd_state (PACKET_vfork_event_feature) + != AUTO_BOOLEAN_FALSE) + q = remote_query_supported_append (q, "vfork-events+"); + } + q = reconcat (q, "qSupported:", q, (char *) NULL); putpkt (q); @@ -12495,6 +12515,12 @@ Show the maximum size of the address (in bits) in a memory packet."), NULL, add_packet_config_cmd (&remote_protocol_packets[PACKET_hwbreak_feature], "hwbreak-feature", "hwbreak-feature", 0); + add_packet_config_cmd (&remote_protocol_packets[PACKET_fork_event_feature], + "fork-event-feature", "fork-event-feature", 0); + + add_packet_config_cmd (&remote_protocol_packets[PACKET_vfork_event_feature], + "vfork-event-feature", "vfork-event-feature", 0); + /* Assert that we've registered "set remote foo-packet" commands for all packet configs. */ {