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[pushed][PATCH 3/7] Extended-remote Linux follow fork
- From: Don Breazeal <donb at codesourcery dot com>
- To: <gdb-patches at sourceware dot org>
- Date: Tue, 12 May 2015 10:28:11 -0700
- Subject: [pushed][PATCH 3/7] Extended-remote Linux follow fork
- Authentication-results: sourceware.org; auth=none
- References: <1431451695-12273-1-git-send-email-donb at codesourcery dot com>
This is the version of the patch that I pushed.
Thanks
--Don
This patch implements basic support for follow-fork and detach-on-fork on
extended-remote Linux targets. Only 'fork' is supported in this patch;
'vfork' support is added n a subsequent patch. This patch depends on
the previous patches in the patch series.
Sufficient extended-remote functionality has been implemented here to pass
gdb.base/multi-forks.exp, as well as gdb.base/foll-fork.exp with the
catchpoint tests commented out. Some other fork tests fail with this
patch because it doesn't provide the architecture support needed for
watchpoint inheritance or fork catchpoints.
The implementation follows the same general structure as for the native
implementation as much as possible.
This implementation includes:
* enabling fork events in linux-low.c in initialize_low and
linux_enable_extended_features
* handling fork events in gdbserver/linux-low.c:handle_extended_wait
- when a fork event occurs in gdbserver, we must do the full creation
of the new process, thread, lwp, and breakpoint lists. This is
required whether or not the new child is destined to be
detached-on-fork, because GDB will make target calls that require all
the structures. In particular we need the breakpoint lists in order
to remove the breakpoints from a detaching child. If we are not
detaching the child we will need all these structures anyway.
- as part of this event handling we store the target_waitstatus in a new
member of the parent lwp_info structure, 'waitstatus'. This
is used to store extended event information for reporting to GDB.
- handle_extended_wait is given a return value, denoting whether the
handled event should be reported to GDB. Previously it had only
handled clone events, which were never reported.
* using a new predicate in gdbserver to control handling of the fork event
(and eventually all extended events) in linux_wait_1. The predicate,
extended_event_reported, checks a target_waitstatus.kind for an
extended ptrace event.
* implementing a new RSP 'T' Stop Reply Packet stop reason: "fork", in
gdbserver/remote-utils.c and remote.c.
* implementing new target and RSP support for target_follow_fork with
target extended-remote. (The RSP components were actually defined in
patch 1, but they see their first use here).
- remote target routine remote_follow_fork, which just sends the 'D;pid'
detach packet to detach the new fork child cleanly. We can't just
call target_detach because the data structures for the forked child
have not been allocated on the host side.
Tested on x64 Ubuntu Lucid, native, remote, extended-remote.
gdb/gdbserver/ChangeLog:
* linux-low.c (handle_extended_wait): Implement return value,
rename argument 'event_child' to 'event_lwp', handle
PTRACE_EVENT_FORK, call internal_error for unrecognized event.
(linux_low_ptrace_options): New function.
(linux_low_filter_event): Call linux_low_ptrace_options,
use different argument fo linux_enable_event_reporting,
use return value from handle_extended_wait.
(extended_event_reported): New function.
(linux_wait_1): Call extended_event_reported and set
status to report fork events.
(linux_write_memory): Add pid to debug message.
(reset_lwp_ptrace_options_callback): New function.
(linux_handle_new_gdb_connection): New function.
(linux_target_ops): Initialize new structure member.
* linux-low.h (struct lwp_info) <waitstatus>: New member.
* lynx-low.c: Initialize new structure member.
* remote-utils.c (prepare_resume_reply): Implement stop reason
"fork" for "T" stop message.
* server.c (handle_query): Call handle_new_gdb_connection.
* server.h (report_fork_events): Declare global flag.
* target.h (struct target_ops) <handle_new_gdb_connection>:
New member.
(target_handle_new_gdb_connection): New macro.
* win32-low.c: Initialize new structure member.
gdb/ChangeLog:
* linux-nat.c (linux_nat_ptrace_options): New function.
(linux_init_ptrace, wait_lwp, linux_nat_filter_event):
Call linux_nat_ptrace_options and use different argument to
linux_enable_event_reporting.
(_initialize_linux_nat): Delete call to
linux_ptrace_set_additional_flags.
* nat/linux-ptrace.c (current_ptrace_options): Rename to
supported_ptrace_options.
(additional_flags): Delete variable.
(linux_check_ptrace_features): Use supported_ptrace_options.
(linux_test_for_tracesysgood, linux_test_for_tracefork):
Likewise, and remove additional_flags check.
(linux_enable_event_reporting): Change 'attached' argument to
'options'. Use supported_ptrace_options.
(ptrace_supports_feature): Change comment. Use
supported_ptrace_options.
(linux_ptrace_set_additional_flags): Delete function.
* nat/linux-ptrace.h (linux_ptrace_set_additional_flags):
Delete function prototype.
* remote.c (remote_fork_event_p): New function.
(remote_detach_pid): New function.
(remote_detach_1): Call remote_detach_pid, don't mourn inferior
if doing detach-on-fork.
(remote_follow_fork): New function.
(remote_parse_stop_reply): Handle new "T" stop reason "fork".
(remote_pid_to_str): Print "process" strings for pid/0/0 ptids.
(init_extended_remote_ops): Initialize to_follow_fork.
---
gdb/ChangeLog | 30 ++++++++
gdb/gdbserver/ChangeLog | 27 +++++++
gdb/gdbserver/linux-low.c | 180 +++++++++++++++++++++++++++++++++++++++----
gdb/gdbserver/linux-low.h | 4 +
gdb/gdbserver/lynx-low.c | 1 +
gdb/gdbserver/remote-utils.c | 14 +++-
gdb/gdbserver/server.c | 3 +
gdb/gdbserver/server.h | 1 +
gdb/gdbserver/target.h | 7 ++
gdb/gdbserver/win32-low.c | 1 +
gdb/linux-nat.c | 37 ++++++---
gdb/nat/linux-ptrace.c | 85 ++++++++------------
gdb/nat/linux-ptrace.h | 1 -
gdb/remote.c | 130 +++++++++++++++++++++++++------
14 files changed, 415 insertions(+), 106 deletions(-)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index be75baf..c9c2e62 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,35 @@
2015-05-12 Don Breazeal <donb@codesourcery.com>
+ * linux-nat.c (linux_nat_ptrace_options): New function.
+ (linux_init_ptrace, wait_lwp, linux_nat_filter_event):
+ Call linux_nat_ptrace_options and use different argument to
+ linux_enable_event_reporting.
+ (_initialize_linux_nat): Delete call to
+ linux_ptrace_set_additional_flags.
+ * nat/linux-ptrace.c (current_ptrace_options): Rename to
+ supported_ptrace_options.
+ (additional_flags): Delete variable.
+ (linux_check_ptrace_features): Use supported_ptrace_options.
+ (linux_test_for_tracesysgood, linux_test_for_tracefork):
+ Likewise, and remove additional_flags check.
+ (linux_enable_event_reporting): Change 'attached' argument to
+ 'options'. Use supported_ptrace_options.
+ (ptrace_supports_feature): Change comment. Use
+ supported_ptrace_options.
+ (linux_ptrace_set_additional_flags): Delete function.
+ * nat/linux-ptrace.h (linux_ptrace_set_additional_flags):
+ Delete function prototype.
+ * remote.c (remote_fork_event_p): New function.
+ (remote_detach_pid): New function.
+ (remote_detach_1): Call remote_detach_pid, don't mourn inferior
+ if doing detach-on-fork.
+ (remote_follow_fork): New function.
+ (remote_parse_stop_reply): Handle new "T" stop reason "fork".
+ (remote_pid_to_str): Print "process" strings for pid/0/0 ptids.
+ (init_extended_remote_ops): Initialize to_follow_fork.
+
+2015-05-12 Don Breazeal <donb@codesourcery.com>
+
* nat/linux-ptrace.c (linux_check_ptrace_features): Change
from static to extern.
* nat/linux-ptrace.h (linux_check_ptrace_features): Declare.
diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 73788ec..0ef695c 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,5 +1,32 @@
2015-05-12 Don Breazeal <donb@codesourcery.com>
+ * linux-low.c (handle_extended_wait): Implement return value,
+ rename argument 'event_child' to 'event_lwp', handle
+ PTRACE_EVENT_FORK, call internal_error for unrecognized event.
+ (linux_low_ptrace_options): New function.
+ (linux_low_filter_event): Call linux_low_ptrace_options,
+ use different argument fo linux_enable_event_reporting,
+ use return value from handle_extended_wait.
+ (extended_event_reported): New function.
+ (linux_wait_1): Call extended_event_reported and set
+ status to report fork events.
+ (linux_write_memory): Add pid to debug message.
+ (reset_lwp_ptrace_options_callback): New function.
+ (linux_handle_new_gdb_connection): New function.
+ (linux_target_ops): Initialize new structure member.
+ * linux-low.h (struct lwp_info) <waitstatus>: New member.
+ * lynx-low.c: Initialize new structure member.
+ * remote-utils.c (prepare_resume_reply): Implement stop reason
+ "fork" for "T" stop message.
+ * server.c (handle_query): Call handle_new_gdb_connection.
+ * server.h (report_fork_events): Declare global flag.
+ * target.h (struct target_ops) <handle_new_gdb_connection>:
+ New member.
+ (target_handle_new_gdb_connection): New macro.
+ * win32-low.c: Initialize new structure member.
+
+2015-05-12 Don Breazeal <donb@codesourcery.com>
+
* mem-break.c (APPEND_TO_LIST): Define macro.
(clone_agent_expr): New function.
(clone_one_breakpoint): New function.
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index 1724b54..b280c17 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -20,6 +20,7 @@
#include "linux-low.h"
#include "nat/linux-osdata.h"
#include "agent.h"
+#include "tdesc.h"
#include "nat/linux-nat.h"
#include "nat/linux-waitpid.h"
@@ -414,22 +415,23 @@ linux_add_process (int pid, int attached)
static CORE_ADDR get_pc (struct lwp_info *lwp);
/* Handle a GNU/Linux extended wait response. If we see a clone
- event, we need to add the new LWP to our list (and not report the
- trap to higher layers). */
+ event, we need to add the new LWP to our list (and return 0 so as
+ not to report the trap to higher layers). */
-static void
-handle_extended_wait (struct lwp_info *event_child, int wstat)
+static int
+handle_extended_wait (struct lwp_info *event_lwp, int wstat)
{
int event = linux_ptrace_get_extended_event (wstat);
- struct thread_info *event_thr = get_lwp_thread (event_child);
+ struct thread_info *event_thr = get_lwp_thread (event_lwp);
struct lwp_info *new_lwp;
- if (event == PTRACE_EVENT_CLONE)
+ if ((event == PTRACE_EVENT_FORK) || (event == PTRACE_EVENT_CLONE))
{
ptid_t ptid;
unsigned long new_pid;
int ret, status;
+ /* Get the pid of the new lwp. */
ptrace (PTRACE_GETEVENTMSG, lwpid_of (event_thr), (PTRACE_TYPE_ARG3) 0,
&new_pid);
@@ -449,6 +451,57 @@ handle_extended_wait (struct lwp_info *event_child, int wstat)
warning ("wait returned unexpected status 0x%x", status);
}
+ if (event == PTRACE_EVENT_FORK)
+ {
+ struct process_info *parent_proc;
+ struct process_info *child_proc;
+ struct lwp_info *child_lwp;
+ struct target_desc *tdesc;
+
+ ptid = ptid_build (new_pid, new_pid, 0);
+
+ if (debug_threads)
+ {
+ debug_printf ("HEW: Got fork event from LWP %ld, "
+ "new child is %d\n",
+ ptid_get_lwp (ptid_of (event_thr)),
+ ptid_get_pid (ptid));
+ }
+
+ /* Add the new process to the tables and clone the breakpoint
+ lists of the parent. We need to do this even if the new process
+ will be detached, since we will need the process object and the
+ breakpoints to remove any breakpoints from memory when we
+ detach, and the client side will access registers. */
+ child_proc = linux_add_process (new_pid, 0);
+ gdb_assert (child_proc != NULL);
+ child_lwp = add_lwp (ptid);
+ gdb_assert (child_lwp != NULL);
+ child_lwp->stopped = 1;
+ parent_proc = get_thread_process (event_thr);
+ child_proc->attached = parent_proc->attached;
+ clone_all_breakpoints (&child_proc->breakpoints,
+ &child_proc->raw_breakpoints,
+ parent_proc->breakpoints);
+
+ tdesc = xmalloc (sizeof (struct target_desc));
+ copy_target_description (tdesc, parent_proc->tdesc);
+ child_proc->tdesc = tdesc;
+ child_lwp->must_set_ptrace_flags = 1;
+
+ /* Save fork info in the parent thread. */
+ event_lwp->waitstatus.kind = TARGET_WAITKIND_FORKED;
+ event_lwp->waitstatus.value.related_pid = ptid;
+ /* The status_pending field contains bits denoting the
+ extended event, so when the pending event is handled,
+ the handler will look at lwp->waitstatus. */
+ event_lwp->status_pending_p = 1;
+ event_lwp->status_pending = wstat;
+
+ /* Report the event. */
+ return 0;
+ }
+
if (debug_threads)
debug_printf ("HEW: Got clone event "
"from LWP %ld, new child is LWP %ld\n",
@@ -477,7 +530,12 @@ handle_extended_wait (struct lwp_info *event_child, int wstat)
new_lwp->status_pending_p = 1;
new_lwp->status_pending = status;
}
+
+ /* Don't report the event. */
+ return 1;
}
+
+ internal_error (__FILE__, __LINE__, _("unknown ptrace event %d"), event);
}
/* Return the PC as read from the regcache of LWP, without any
@@ -1935,6 +1993,22 @@ check_stopped_by_watchpoint (struct lwp_info *child)
return child->stop_reason == TARGET_STOPPED_BY_WATCHPOINT;
}
+/* Return the ptrace options that we want to try to enable. */
+
+static int
+linux_low_ptrace_options (int attached)
+{
+ int options = 0;
+
+ if (!attached)
+ options |= PTRACE_O_EXITKILL;
+
+ if (report_fork_events)
+ options |= PTRACE_O_TRACEFORK;
+
+ return options;
+}
+
/* Do low-level handling of the event, and check if we should go on
and pass it to caller code. Return the affected lwp if we are, or
NULL otherwise. */
@@ -2022,8 +2096,9 @@ linux_low_filter_event (int lwpid, int wstat)
if (WIFSTOPPED (wstat) && child->must_set_ptrace_flags)
{
struct process_info *proc = find_process_pid (pid_of (thread));
+ int options = linux_low_ptrace_options (proc->attached);
- linux_enable_event_reporting (lwpid, proc->attached);
+ linux_enable_event_reporting (lwpid, options);
child->must_set_ptrace_flags = 0;
}
@@ -2033,8 +2108,12 @@ linux_low_filter_event (int lwpid, int wstat)
&& linux_is_extended_waitstatus (wstat))
{
child->stop_pc = get_pc (child);
- handle_extended_wait (child, wstat);
- return NULL;
+ if (handle_extended_wait (child, wstat))
+ {
+ /* The event has been handled, so just return without
+ reporting it. */
+ return NULL;
+ }
}
/* Check first whether this was a SW/HW breakpoint before checking
@@ -2622,6 +2701,18 @@ ignore_event (struct target_waitstatus *ourstatus)
return null_ptid;
}
+/* Return non-zero if WAITSTATUS reflects an extended linux
+ event. Otherwise, return zero. */
+
+static int
+extended_event_reported (const struct target_waitstatus *waitstatus)
+{
+ if (waitstatus == NULL)
+ return 0;
+
+ return (waitstatus->kind == TARGET_WAITKIND_FORKED);
+}
+
/* Wait for process, returns status. */
static ptid_t
@@ -2988,7 +3079,8 @@ linux_wait_1 (ptid_t ptid,
&& !bp_explains_trap && !trace_event)
|| (gdb_breakpoint_here (event_child->stop_pc)
&& gdb_condition_true_at_breakpoint (event_child->stop_pc)
- && gdb_no_commands_at_breakpoint (event_child->stop_pc)));
+ && gdb_no_commands_at_breakpoint (event_child->stop_pc))
+ || extended_event_reported (&event_child->waitstatus));
run_breakpoint_commands (event_child->stop_pc);
@@ -3010,6 +3102,13 @@ linux_wait_1 (ptid_t ptid,
paddress (event_child->stop_pc),
paddress (event_child->step_range_start),
paddress (event_child->step_range_end));
+ if (extended_event_reported (&event_child->waitstatus))
+ {
+ char *str = target_waitstatus_to_string (ourstatus);
+ debug_printf ("LWP %ld: extended event with waitstatus %s\n",
+ lwpid_of (get_lwp_thread (event_child)), str);
+ xfree (str);
+ }
}
/* We're not reporting this breakpoint to GDB, so apply the
@@ -3119,7 +3218,17 @@ linux_wait_1 (ptid_t ptid,
unstop_all_lwps (1, event_child);
}
- ourstatus->kind = TARGET_WAITKIND_STOPPED;
+ if (extended_event_reported (&event_child->waitstatus))
+ {
+ /* If the reported event is a fork, vfork or exec, let GDB know. */
+ ourstatus->kind = event_child->waitstatus.kind;
+ ourstatus->value = event_child->waitstatus.value;
+
+ /* Clear the event lwp's waitstatus since we handled it already. */
+ event_child->waitstatus.kind = TARGET_WAITKIND_IGNORE;
+ }
+ else
+ ourstatus->kind = TARGET_WAITKIND_STOPPED;
/* Now that we've selected our final event LWP, un-adjust its PC if
it was a software breakpoint, and the client doesn't know we can
@@ -3152,7 +3261,7 @@ linux_wait_1 (ptid_t ptid,
but, it stopped for other reasons. */
ourstatus->value.sig = gdb_signal_from_host (WSTOPSIG (w));
}
- else
+ else if (ourstatus->kind == TARGET_WAITKIND_STOPPED)
{
ourstatus->value.sig = gdb_signal_from_host (WSTOPSIG (w));
}
@@ -4996,8 +5105,8 @@ linux_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr, int len)
val = val & 0xffff;
else if (len == 3)
val = val & 0xffffff;
- debug_printf ("Writing %0*x to 0x%08lx\n", 2 * ((len < 4) ? len : 4),
- val, (long)memaddr);
+ debug_printf ("Writing %0*x to 0x%08lx in process %d\n",
+ 2 * ((len < 4) ? len : 4), val, (long)memaddr, pid);
}
/* Fill start and end extra bytes of buffer with existing memory data. */
@@ -5454,6 +5563,48 @@ linux_supports_vfork_events (void)
return linux_supports_tracefork ();
}
+/* Callback for 'find_inferior'. Set the (possibly changed) ptrace
+ options for the specified lwp. */
+
+static int
+reset_lwp_ptrace_options_callback (struct inferior_list_entry *entry,
+ void *args)
+{
+ struct thread_info *thread = (struct thread_info *) entry;
+ struct lwp_info *lwp = get_thread_lwp (thread);
+
+ if (!lwp->stopped)
+ {
+ /* Stop the lwp so we can modify its ptrace options. */
+ lwp->must_set_ptrace_flags = 1;
+ linux_stop_lwp (lwp);
+ }
+ else
+ {
+ /* Already stopped; go ahead and set the ptrace options. */
+ struct process_info *proc = find_process_pid (pid_of (thread));
+ int options = linux_low_ptrace_options (proc->attached);
+
+ linux_enable_event_reporting (lwpid_of (thread), options);
+ lwp->must_set_ptrace_flags = 0;
+ }
+
+ return 0;
+}
+
+/* Target hook for 'handle_new_gdb_connection'. Causes a reset of the
+ ptrace flags for all inferiors. This is in case the new GDB connection
+ doesn't support the same set of events that the previous one did. */
+
+static void
+linux_handle_new_gdb_connection (void)
+{
+ pid_t pid;
+
+ /* Request that all the lwps reset their ptrace options. */
+ find_inferior (&all_threads, reset_lwp_ptrace_options_callback , &pid);
+}
+
static int
linux_supports_disable_randomization (void)
{
@@ -6429,6 +6580,7 @@ static struct target_ops linux_target_ops = {
linux_supports_multi_process,
linux_supports_fork_events,
linux_supports_vfork_events,
+ linux_handle_new_gdb_connection,
#ifdef USE_THREAD_DB
thread_db_handle_monitor_command,
#else
diff --git a/gdb/gdbserver/linux-low.h b/gdb/gdbserver/linux-low.h
index 1ae3701..41067d6 100644
--- a/gdb/gdbserver/linux-low.h
+++ b/gdb/gdbserver/linux-low.h
@@ -271,6 +271,10 @@ struct lwp_info
/* When stopped is set, the last wait status recorded for this lwp. */
int last_status;
+ /* This is used to store extended ptrace event information until
+ it is reported to GDB. */
+ struct target_waitstatus waitstatus;
+
/* When stopped is set, this is where the lwp last stopped, with
decr_pc_after_break already accounted for. If the LWP is
running, this is the address at which the lwp was resumed. */
diff --git a/gdb/gdbserver/lynx-low.c b/gdb/gdbserver/lynx-low.c
index f087416..ee7b28a 100644
--- a/gdb/gdbserver/lynx-low.c
+++ b/gdb/gdbserver/lynx-low.c
@@ -764,6 +764,7 @@ static struct target_ops lynx_target_ops = {
NULL, /* supports_multi_process */
NULL, /* supports_fork_events */
NULL, /* supports_vfork_events */
+ NULL, /* handle_new_gdb_connection */
NULL, /* handle_monitor_command */
};
diff --git a/gdb/gdbserver/remote-utils.c b/gdb/gdbserver/remote-utils.c
index 1de86be..6078348 100644
--- a/gdb/gdbserver/remote-utils.c
+++ b/gdb/gdbserver/remote-utils.c
@@ -1114,12 +1114,24 @@ prepare_resume_reply (char *buf, ptid_t ptid,
switch (status->kind)
{
case TARGET_WAITKIND_STOPPED:
+ case TARGET_WAITKIND_FORKED:
{
struct thread_info *saved_thread;
const char **regp;
struct regcache *regcache;
- sprintf (buf, "T%02x", status->value.sig);
+ if (status->kind == TARGET_WAITKIND_FORKED && report_fork_events)
+ {
+ enum gdb_signal signal = GDB_SIGNAL_TRAP;
+
+ sprintf (buf, "T%02xfork:", signal);
+ buf += strlen (buf);
+ buf = write_ptid (buf, status->value.related_pid);
+ strcat (buf, ";");
+ }
+ else
+ sprintf (buf, "T%02x", status->value.sig);
+
buf += strlen (buf);
saved_thread = current_thread;
diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c
index 1544e99..3969267 100644
--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -2160,6 +2160,9 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
if (the_target->pid_to_exec_file != NULL)
strcat (own_buf, ";qXfer:exec-file:read+");
+ /* Reinitialize the target as needed for the new connection. */
+ target_handle_new_gdb_connection ();
+
return;
}
diff --git a/gdb/gdbserver/server.h b/gdb/gdbserver/server.h
index 91d4080..696a24e 100644
--- a/gdb/gdbserver/server.h
+++ b/gdb/gdbserver/server.h
@@ -84,6 +84,7 @@ extern int disable_packet_qfThreadInfo;
extern int run_once;
extern int multi_process;
+extern int report_fork_events;
extern int non_stop;
/* True if the "swbreak+" feature is active. In that case, GDB wants
diff --git a/gdb/gdbserver/target.h b/gdb/gdbserver/target.h
index 697b223..8d23383 100644
--- a/gdb/gdbserver/target.h
+++ b/gdb/gdbserver/target.h
@@ -287,6 +287,9 @@ struct target_ops
/* Returns true if vfork events are supported. */
int (*supports_vfork_events) (void);
+ /* Allows target to re-initialize connection-specific settings. */
+ void (*handle_new_gdb_connection) (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 *);
@@ -434,6 +437,10 @@ int kill_inferior (int);
(the_target->supports_vfork_events ? \
(*the_target->supports_vfork_events) () : 0)
+#define target_handle_new_gdb_connection() \
+ (the_target->handle_new_gdb_connection ? \
+ (*the_target->handle_new_gdb_connection) () : 0)
+
#define detach_inferior(pid) \
(*the_target->detach) (pid)
diff --git a/gdb/gdbserver/win32-low.c b/gdb/gdbserver/win32-low.c
index a58f963..699115c 100644
--- a/gdb/gdbserver/win32-low.c
+++ b/gdb/gdbserver/win32-low.c
@@ -1833,6 +1833,7 @@ static struct target_ops win32_target_ops = {
NULL, /* supports_multi_process */
NULL, /* supports_fork_events */
NULL, /* supports_vfork_events */
+ NULL, /* handle_new_gdb_connection */
NULL, /* handle_monitor_command */
NULL, /* core_of_thread */
NULL, /* read_loadmap */
diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c
index b04aa68..f95e76c 100644
--- a/gdb/linux-nat.c
+++ b/gdb/linux-nat.c
@@ -368,6 +368,25 @@ pull_pid_from_list (struct simple_pid_list **listp, int pid, int *statusp)
return 0;
}
+/* Return the ptrace options that we want to try to enable. */
+
+static int
+linux_nat_ptrace_options (int attached)
+{
+ int options = 0;
+
+ if (!attached)
+ options |= PTRACE_O_EXITKILL;
+
+ options |= (PTRACE_O_TRACESYSGOOD
+ | PTRACE_O_TRACEVFORKDONE
+ | PTRACE_O_TRACEVFORK
+ | PTRACE_O_TRACEFORK
+ | PTRACE_O_TRACEEXEC);
+
+ return options;
+}
+
/* Initialize ptrace warnings and check for supported ptrace
features given PID.
@@ -376,7 +395,9 @@ pull_pid_from_list (struct simple_pid_list **listp, int pid, int *statusp)
static void
linux_init_ptrace (pid_t pid, int attached)
{
- linux_enable_event_reporting (pid, attached);
+ int options = linux_nat_ptrace_options (attached);
+
+ linux_enable_event_reporting (pid, options);
linux_ptrace_init_warnings ();
}
@@ -2301,8 +2322,9 @@ wait_lwp (struct lwp_info *lp)
if (lp->must_set_ptrace_flags)
{
struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
+ int options = linux_nat_ptrace_options (inf->attach_flag);
- linux_enable_event_reporting (ptid_get_lwp (lp->ptid), inf->attach_flag);
+ linux_enable_event_reporting (ptid_get_lwp (lp->ptid), options);
lp->must_set_ptrace_flags = 0;
}
@@ -3102,8 +3124,9 @@ linux_nat_filter_event (int lwpid, int status)
if (WIFSTOPPED (status) && lp->must_set_ptrace_flags)
{
struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
+ int options = linux_nat_ptrace_options (inf->attach_flag);
- linux_enable_event_reporting (ptid_get_lwp (lp->ptid), inf->attach_flag);
+ linux_enable_event_reporting (ptid_get_lwp (lp->ptid), options);
lp->must_set_ptrace_flags = 0;
}
@@ -5028,14 +5051,6 @@ Enables printf debugging output."),
sigdelset (&suspend_mask, SIGCHLD);
sigemptyset (&blocked_mask);
-
- /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to
- support read-only process state. */
- linux_ptrace_set_additional_flags (PTRACE_O_TRACESYSGOOD
- | PTRACE_O_TRACEVFORKDONE
- | PTRACE_O_TRACEVFORK
- | PTRACE_O_TRACEFORK
- | PTRACE_O_TRACEEXEC);
}
diff --git a/gdb/nat/linux-ptrace.c b/gdb/nat/linux-ptrace.c
index aba3da8..fb12606 100644
--- a/gdb/nat/linux-ptrace.c
+++ b/gdb/nat/linux-ptrace.c
@@ -25,14 +25,10 @@
#include <stdint.h>
-/* Stores the currently supported ptrace options. A value of
- -1 means we did not check for features yet. A value of 0 means
- there are no supported features. */
-static int current_ptrace_options = -1;
-
-/* Additional flags to test. */
-
-static int additional_flags;
+/* Stores the ptrace options supported by the running kernel.
+ A value of -1 means we did not check for features yet. A value
+ of 0 means there are no supported features. */
+static int supported_ptrace_options = -1;
/* Find all possible reasons we could fail to attach PID and append
these as strings to the already initialized BUFFER. '\0'
@@ -343,7 +339,7 @@ linux_check_ptrace_features (void)
int child_pid, ret, status;
/* Initialize the options. */
- current_ptrace_options = 0;
+ supported_ptrace_options = 0;
/* Fork a child so we can do some testing. The child will call
linux_child_function and will get traced. The child will
@@ -387,14 +383,11 @@ linux_test_for_tracesysgood (int child_pid)
{
int ret;
- if ((additional_flags & PTRACE_O_TRACESYSGOOD) == 0)
- return;
-
ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0,
(PTRACE_TYPE_ARG4) PTRACE_O_TRACESYSGOOD);
if (ret == 0)
- current_ptrace_options |= PTRACE_O_TRACESYSGOOD;
+ supported_ptrace_options |= PTRACE_O_TRACESYSGOOD;
}
/* Determine if PTRACE_O_TRACEFORK can be used to follow fork
@@ -414,15 +407,12 @@ linux_test_for_tracefork (int child_pid)
if (ret != 0)
return;
- if ((additional_flags & PTRACE_O_TRACEVFORKDONE) != 0)
- {
- /* Check if the target supports PTRACE_O_TRACEVFORKDONE. */
- ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0,
- (PTRACE_TYPE_ARG4) (PTRACE_O_TRACEFORK
- | PTRACE_O_TRACEVFORKDONE));
- if (ret == 0)
- current_ptrace_options |= PTRACE_O_TRACEVFORKDONE;
- }
+ /* Check if the target supports PTRACE_O_TRACEVFORKDONE. */
+ ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0,
+ (PTRACE_TYPE_ARG4) (PTRACE_O_TRACEFORK
+ | PTRACE_O_TRACEVFORKDONE));
+ if (ret == 0)
+ supported_ptrace_options |= PTRACE_O_TRACEVFORKDONE;
/* Setting PTRACE_O_TRACEFORK did not cause an error, however we
don't know for sure that the feature is available; old
@@ -458,10 +448,10 @@ linux_test_for_tracefork (int child_pid)
/* We got the PID from the grandchild, which means fork
tracing is supported. */
- current_ptrace_options |= PTRACE_O_TRACECLONE;
- current_ptrace_options |= (additional_flags & (PTRACE_O_TRACEFORK
- | PTRACE_O_TRACEVFORK
- | PTRACE_O_TRACEEXEC));
+ supported_ptrace_options |= PTRACE_O_TRACECLONE;
+ supported_ptrace_options |= (PTRACE_O_TRACEFORK
+ | PTRACE_O_TRACEVFORK
+ | PTRACE_O_TRACEEXEC);
/* Do some cleanup and kill the grandchild. */
my_waitpid (second_pid, &second_status, 0);
@@ -489,33 +479,31 @@ linux_test_for_exitkill (int child_pid)
(PTRACE_TYPE_ARG4) PTRACE_O_EXITKILL);
if (ret == 0)
- current_ptrace_options |= PTRACE_O_EXITKILL;
+ supported_ptrace_options |= PTRACE_O_EXITKILL;
}
/* Enable reporting of all currently supported ptrace events.
- ATTACHED should be nonzero if we have attached to the inferior. */
+ OPTIONS is a bit mask of extended features we want enabled,
+ if supported by the kernel. PTRACE_O_TRACECLONE is always
+ enabled, if supported. */
void
-linux_enable_event_reporting (pid_t pid, int attached)
+linux_enable_event_reporting (pid_t pid, int options)
{
- int ptrace_options;
-
/* Check if we have initialized the ptrace features for this
target. If not, do it now. */
- if (current_ptrace_options == -1)
+ if (supported_ptrace_options == -1)
linux_check_ptrace_features ();
- ptrace_options = current_ptrace_options;
- if (attached)
- {
- /* When attached to our inferior, we do not want the inferior
- to die with us if we terminate unexpectedly. */
- ptrace_options &= ~PTRACE_O_EXITKILL;
- }
+ /* We always want clone events. */
+ options |= PTRACE_O_TRACECLONE;
+
+ /* Filter out unsupported options. */
+ options &= supported_ptrace_options;
/* Set the options. */
ptrace (PTRACE_SETOPTIONS, pid, (PTRACE_TYPE_ARG3) 0,
- (PTRACE_TYPE_ARG4) (uintptr_t) ptrace_options);
+ (PTRACE_TYPE_ARG4) (uintptr_t) options);
}
/* Disable reporting of all currently supported ptrace events. */
@@ -528,16 +516,16 @@ linux_disable_event_reporting (pid_t pid)
}
/* Returns non-zero if PTRACE_OPTIONS is contained within
- CURRENT_PTRACE_OPTIONS, therefore supported. Returns 0
+ SUPPORTED_PTRACE_OPTIONS, therefore supported. Returns 0
otherwise. */
static int
ptrace_supports_feature (int ptrace_options)
{
- if (current_ptrace_options == -1)
+ if (supported_ptrace_options == -1)
linux_check_ptrace_features ();
- return ((current_ptrace_options & ptrace_options) == ptrace_options);
+ return ((supported_ptrace_options & ptrace_options) == ptrace_options);
}
/* Returns non-zero if PTRACE_EVENT_FORK is supported by ptrace,
@@ -595,17 +583,6 @@ linux_ptrace_init_warnings (void)
linux_ptrace_test_ret_to_nx ();
}
-/* Set additional ptrace flags to use. Some such flags may be checked
- by the implementation above. This function must be called before
- any other function in this file; otherwise the flags may not take
- effect appropriately. */
-
-void
-linux_ptrace_set_additional_flags (int flags)
-{
- additional_flags = flags;
-}
-
/* Extract extended ptrace event from wait status. */
int
diff --git a/gdb/nat/linux-ptrace.h b/gdb/nat/linux-ptrace.h
index 03d98c9..1db0cde 100644
--- a/gdb/nat/linux-ptrace.h
+++ b/gdb/nat/linux-ptrace.h
@@ -156,7 +156,6 @@ extern int linux_supports_tracefork (void);
extern int linux_supports_traceclone (void);
extern int linux_supports_tracevforkdone (void);
extern int linux_supports_tracesysgood (void);
-extern void linux_ptrace_set_additional_flags (int);
extern int linux_ptrace_get_extended_event (int wstat);
extern int linux_is_extended_waitstatus (int wstat);
extern int linux_wstatus_maybe_breakpoint (int wstat);
diff --git a/gdb/remote.c b/gdb/remote.c
index 6dae920..390d30d 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -1462,6 +1462,14 @@ remote_multi_process_p (struct remote_state *rs)
return packet_support (PACKET_multiprocess_feature) == PACKET_ENABLE;
}
+/* Returns true if fork events are supported. */
+
+static int
+remote_fork_event_p (struct remote_state *rs)
+{
+ return packet_support (PACKET_fork_event_feature) == PACKET_ENABLE;
+}
+
/* Tokens for use by the asynchronous signal handlers for SIGINT. */
static struct async_signal_handler *async_sigint_remote_twice_token;
static struct async_signal_handler *async_sigint_remote_token;
@@ -4430,16 +4438,42 @@ remote_open_1 (const char *name, int from_tty,
wait_forever_enabled_p = 1;
}
-/* This takes a program previously attached to and detaches it. After
- this is done, GDB can be used to debug some other program. We
- better not have left any breakpoints in the target program or it'll
- die when it hits one. */
+/* Detach the specified process. */
+
+static void
+remote_detach_pid (int pid)
+{
+ struct remote_state *rs = get_remote_state ();
+
+ if (remote_multi_process_p (rs))
+ xsnprintf (rs->buf, get_remote_packet_size (), "D;%x", pid);
+ else
+ strcpy (rs->buf, "D");
+
+ putpkt (rs->buf);
+ getpkt (&rs->buf, &rs->buf_size, 0);
+
+ if (rs->buf[0] == 'O' && rs->buf[1] == 'K')
+ ;
+ else if (rs->buf[0] == '\0')
+ error (_("Remote doesn't know how to detach"));
+ else
+ error (_("Can't detach process."));
+}
+
+/* This detaches a program to which we previously attached, using
+ inferior_ptid to identify the process. After this is done, GDB
+ can be used to debug some other program. We better not have left
+ any breakpoints in the target program or it'll die when it hits
+ one. */
static void
-remote_detach_1 (const char *args, int from_tty, int extended)
+remote_detach_1 (const char *args, int from_tty)
{
int pid = ptid_get_pid (inferior_ptid);
struct remote_state *rs = get_remote_state ();
+ struct thread_info *tp = find_thread_ptid (inferior_ptid);
+ int is_fork_parent;
if (args)
error (_("Argument given to \"detach\" when remotely debugging."));
@@ -4458,37 +4492,74 @@ remote_detach_1 (const char *args, int from_tty, int extended)
}
/* Tell the remote target to detach. */
- if (remote_multi_process_p (rs))
- xsnprintf (rs->buf, get_remote_packet_size (), "D;%x", pid);
- else
- strcpy (rs->buf, "D");
+ remote_detach_pid (pid);
- putpkt (rs->buf);
- getpkt (&rs->buf, &rs->buf_size, 0);
-
- if (rs->buf[0] == 'O' && rs->buf[1] == 'K')
- ;
- else if (rs->buf[0] == '\0')
- error (_("Remote doesn't know how to detach"));
- else
- error (_("Can't detach process."));
-
- if (from_tty && !extended)
+ if (from_tty && !rs->extended)
puts_filtered (_("Ending remote debugging.\n"));
- target_mourn_inferior ();
+ /* Check to see if we are detaching a fork parent. Note that if we
+ are detaching a fork child, tp == NULL. */
+ is_fork_parent = (tp != NULL
+ && tp->pending_follow.kind == TARGET_WAITKIND_FORKED);
+
+ /* If doing detach-on-fork, we don't mourn, because that will delete
+ breakpoints that should be available for the followed inferior. */
+ if (!is_fork_parent)
+ target_mourn_inferior ();
+ else
+ {
+ inferior_ptid = null_ptid;
+ detach_inferior (pid);
+ }
}
static void
remote_detach (struct target_ops *ops, const char *args, int from_tty)
{
- remote_detach_1 (args, from_tty, 0);
+ remote_detach_1 (args, from_tty);
}
static void
extended_remote_detach (struct target_ops *ops, const char *args, int from_tty)
{
- remote_detach_1 (args, from_tty, 1);
+ remote_detach_1 (args, from_tty);
+}
+
+/* Target follow-fork function for remote targets. On entry, and
+ at return, the current inferior is the fork parent.
+
+ Note that although this is currently only used for extended-remote,
+ it is named remote_follow_fork in anticipation of using it for the
+ remote target as well. */
+
+static int
+remote_follow_fork (struct target_ops *ops, int follow_child,
+ int detach_fork)
+{
+ struct remote_state *rs = get_remote_state ();
+
+ if (remote_fork_event_p (rs))
+ {
+ /* When following the parent and detaching the child, we detach
+ the child here. For the case of following the child and
+ detaching the parent, the detach is done in the target-
+ independent follow fork code in infrun.c. We can't use
+ target_detach when detaching an unfollowed child because
+ the client side doesn't know anything about the child. */
+ if (detach_fork && !follow_child)
+ {
+ /* Detach the fork child. */
+ ptid_t child_ptid;
+ pid_t child_pid;
+
+ child_ptid = inferior_thread ()->pending_follow.value.related_pid;
+ child_pid = ptid_get_pid (child_ptid);
+
+ remote_detach_pid (child_pid);
+ detach_inferior (child_pid);
+ }
+ }
+ return 0;
}
/* Same as remote_detach, but don't send the "D" packet; just disconnect. */
@@ -5651,6 +5722,11 @@ Packet: '%s'\n"),
p = unpack_varlen_hex (++p1, &c);
event->core = c;
}
+ else if (strncmp (p, "fork", p1 - p) == 0)
+ {
+ event->ws.value.related_pid = read_ptid (++p1, &p);
+ event->ws.kind = TARGET_WAITKIND_FORKED;
+ }
else
{
ULONGEST pnum;
@@ -9505,8 +9581,11 @@ remote_pid_to_str (struct target_ops *ops, ptid_t ptid)
if (ptid_equal (magic_null_ptid, ptid))
xsnprintf (buf, sizeof buf, "Thread <main>");
else if (rs->extended && remote_multi_process_p (rs))
- xsnprintf (buf, sizeof buf, "Thread %d.%ld",
- ptid_get_pid (ptid), ptid_get_lwp (ptid));
+ if (ptid_get_lwp (ptid) == 0)
+ return normal_pid_to_str (ptid);
+ else
+ xsnprintf (buf, sizeof buf, "Thread %d.%ld",
+ ptid_get_pid (ptid), ptid_get_lwp (ptid));
else
xsnprintf (buf, sizeof buf, "Thread %ld",
ptid_get_lwp (ptid));
@@ -11870,6 +11949,7 @@ Specify the serial device it is connected to (e.g. /dev/ttya).";
extended_remote_ops.to_kill = extended_remote_kill;
extended_remote_ops.to_supports_disable_randomization
= extended_remote_supports_disable_randomization;
+ extended_remote_ops.to_follow_fork = remote_follow_fork;
}
static int
--
1.8.1.1