From 84e46146f7e8f26eafd2e9a6f0bc229423e0950c Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Sat, 28 Jun 2008 11:15:34 +0000 Subject: [PATCH] gdb/ 2008-06-28 Pedro Alves * linux-nat.c (enum sigchld_state): New. (linux_nat_async_events_state): Renamed from linux_nat_async_events_enabled. (linux_nat_event_pipe_push, my_waitpid): Adjust. (sigchld_default_action): New. (lin_lwp_attach_lwp): Adjust. Call linux_nat_async_events unconditionally. (linux_nat_create_inferior): Set events state to sigchld_default state. (linux_nat_resume): Adjust. (linux_nat_wait): Call linux_nat_async_events unconditionally. (sigchld_handler): Adjust. (linux_nat_async_mask): Don't set SIGCHLD actions here. (get_pending_events): Adjust. (linux_nat_async_events): Rewrite to handle enum sigchld_state instead of a boolean. (linux_nat_async): Adjust. (_initialize_linux_nat): Capture default SIGCHLD action into sigchld_default_action. gdb/testsuite/ 2008-06-28 Pedro Alves * gdb.base/sigchld.c, gdb.base/sigchld.exp: New test. --- gdb/ChangeLog | 22 ++++ gdb/linux-nat.c | 160 ++++++++++++++++++----------- gdb/testsuite/ChangeLog | 4 + gdb/testsuite/gdb.base/sigchld.c | 37 +++++++ gdb/testsuite/gdb.base/sigchld.exp | 45 ++++++++ 5 files changed, 210 insertions(+), 58 deletions(-) create mode 100644 gdb/testsuite/gdb.base/sigchld.c create mode 100644 gdb/testsuite/gdb.base/sigchld.exp diff --git a/gdb/ChangeLog b/gdb/ChangeLog index d54679d9d7f..0589c7f83c8 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,25 @@ +2008-06-28 Pedro Alves + + * linux-nat.c (enum sigchld_state): New. + (linux_nat_async_events_state): Renamed from + linux_nat_async_events_enabled. + (linux_nat_event_pipe_push, my_waitpid): Adjust. + (sigchld_default_action): New. + (lin_lwp_attach_lwp): Adjust. Call linux_nat_async_events + unconditionally. + (linux_nat_create_inferior): Set events state to sigchld_default + state. + (linux_nat_resume): Adjust. + (linux_nat_wait): Call linux_nat_async_events unconditionally. + (sigchld_handler): Adjust. + (linux_nat_async_mask): Don't set SIGCHLD actions here. + (get_pending_events): Adjust. + (linux_nat_async_events): Rewrite to handle enum sigchld_state + instead of a boolean. + (linux_nat_async): Adjust. + (_initialize_linux_nat): Capture default SIGCHLD action into + sigchld_default_action. + 2008-06-28 Vladimir Prus * breakpoint.c (moribund_locations): New. diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c index f981e650170..964337884e0 100644 --- a/gdb/linux-nat.c +++ b/gdb/linux-nat.c @@ -256,11 +256,24 @@ static int linux_nat_event_pipe[2] = { -1, -1 }; /* Number of queued events in the pipe. */ static volatile int linux_nat_num_queued_events; -/* If async mode is on, true if we're listening for events; false if - target events are blocked. */ -static int linux_nat_async_events_enabled; +/* The possible SIGCHLD handling states. */ -static int linux_nat_async_events (int enable); +enum sigchld_state +{ + /* SIGCHLD disabled, with action set to sigchld_handler, for the + sigsuspend in linux_nat_wait. */ + sigchld_sync, + /* SIGCHLD enabled, with action set to async_sigchld_handler. */ + sigchld_async, + /* Set SIGCHLD to default action. Used while creating an + inferior. */ + sigchld_default +}; + +/* The current SIGCHLD handling state. */ +static enum sigchld_state linux_nat_async_events_state; + +static enum sigchld_state linux_nat_async_events (enum sigchld_state enable); static void pipe_to_local_event_queue (void); static void local_event_queue_to_pipe (void); static void linux_nat_event_pipe_push (int pid, int status, int options); @@ -294,8 +307,8 @@ queued_waitpid (int pid, int *status, int flags) if (debug_linux_nat_async) fprintf_unfiltered (gdb_stdlog, "\ -QWPID: linux_nat_async_events_enabled(%d), linux_nat_num_queued_events(%d)\n", - linux_nat_async_events_enabled, +QWPID: linux_nat_async_events_state(%d), linux_nat_num_queued_events(%d)\n", + linux_nat_async_events_state, linux_nat_num_queued_events); if (flags & __WALL) @@ -441,7 +454,7 @@ my_waitpid (int pid, int *status, int flags) int ret; /* There should be no concurrent calls to waitpid. */ - gdb_assert (!linux_nat_async_events_enabled); + gdb_assert (linux_nat_async_events_state == sigchld_sync); ret = queued_waitpid (pid, status, flags); if (ret != -1) @@ -862,6 +875,9 @@ struct sigaction sync_sigchld_action; /* SIGCHLD action for asynchronous mode. */ static struct sigaction async_sigchld_action; + +/* SIGCHLD default action, to pass to new inferiors. */ +static struct sigaction sigchld_default_action; /* Prototypes for local functions. */ @@ -1185,12 +1201,11 @@ int lin_lwp_attach_lwp (ptid_t ptid) { struct lwp_info *lp; - int async_events_were_enabled = 0; + enum sigchld_state async_events_original_state; gdb_assert (is_lwp (ptid)); - if (target_can_async_p ()) - async_events_were_enabled = linux_nat_async_events (0); + async_events_original_state = linux_nat_async_events (sigchld_sync); lp = find_lwp_pid (ptid); @@ -1255,9 +1270,7 @@ lin_lwp_attach_lwp (ptid_t ptid) lp->stopped = 1; } - if (async_events_were_enabled) - linux_nat_async_events (1); - + linux_nat_async_events (async_events_original_state); return 0; } @@ -1271,6 +1284,8 @@ linux_nat_create_inferior (char *exec_file, char *allargs, char **env, we have to mask the async mode. */ if (target_can_async_p ()) + /* Mask async mode. Creating a child requires a loop calling + wait_for_inferior currently. */ saved_async = linux_nat_async_mask (0); else { @@ -1281,6 +1296,12 @@ linux_nat_create_inferior (char *exec_file, char *allargs, char **env, sigdelset (&suspend_mask, SIGCHLD); } + /* Set SIGCHLD to the default action, until after execing the child, + since the inferior inherits the superior's signal mask. It will + be blocked again in linux_nat_wait, which is only reached after + the inferior execing. */ + linux_nat_async_events (sigchld_default); + linux_ops->to_create_inferior (exec_file, allargs, env, from_tty); if (saved_async) @@ -1512,7 +1533,7 @@ linux_nat_resume (ptid_t ptid, int step, enum target_signal signo) if (target_can_async_p ()) /* Block events while we're here. */ - linux_nat_async_events (0); + linux_nat_async_events (sigchld_sync); /* A specific PTID means `step only this process id'. */ resume_all = (PIDGET (ptid) == -1); @@ -2574,9 +2595,8 @@ linux_nat_wait (ptid_t ptid, struct target_waitstatus *ourstatus) sigemptyset (&flush_mask); - if (target_can_async_p ()) - /* Block events while we're here. */ - target_async (NULL, 0); + /* Block events while we're here. */ + linux_nat_async_events (sigchld_sync); retry: @@ -3035,7 +3055,7 @@ static void sigchld_handler (int signo) { if (linux_nat_async_enabled - && linux_nat_async_events_enabled + && linux_nat_async_events_state != sigchld_sync && signo == SIGCHLD) /* It is *always* a bug to hit this. */ internal_error (__FILE__, __LINE__, @@ -3894,15 +3914,9 @@ linux_nat_async_mask (int mask) { linux_nat_async (NULL, 0); linux_nat_async_mask_value = mask; - /* We're in sync mode. Make sure SIGCHLD isn't handled by - async_sigchld_handler when we come out of sigsuspend in - linux_nat_wait. */ - sigaction (SIGCHLD, &sync_sigchld_action, NULL); } else { - /* Restore the async handler. */ - sigaction (SIGCHLD, &async_sigchld_action, NULL); linux_nat_async_mask_value = mask; linux_nat_async (inferior_event_handler, 0); } @@ -3960,7 +3974,8 @@ get_pending_events (void) { int status, options, pid; - if (!linux_nat_async_enabled || !linux_nat_async_events_enabled) + if (!linux_nat_async_enabled + || linux_nat_async_events_state != sigchld_async) internal_error (__FILE__, __LINE__, "get_pending_events called with async masked"); @@ -4014,44 +4029,75 @@ async_sigchld_handler (int signo) get_pending_events (); } -/* Enable or disable async SIGCHLD handling. */ +/* Set SIGCHLD handling state to STATE. Returns previous state. */ -static int -linux_nat_async_events (int enable) +static enum sigchld_state +linux_nat_async_events (enum sigchld_state state) { - int current_state = linux_nat_async_events_enabled; + enum sigchld_state current_state = linux_nat_async_events_state; if (debug_linux_nat_async) fprintf_unfiltered (gdb_stdlog, - "LNAE: enable(%d): linux_nat_async_events_enabled(%d), " + "LNAE: state(%d): linux_nat_async_events_state(%d), " "linux_nat_num_queued_events(%d)\n", - enable, linux_nat_async_events_enabled, + state, linux_nat_async_events_state, linux_nat_num_queued_events); - if (current_state != enable) + if (current_state != state) { sigset_t mask; sigemptyset (&mask); sigaddset (&mask, SIGCHLD); - if (enable) - { - /* Unblock target events. */ - linux_nat_async_events_enabled = 1; - - local_event_queue_to_pipe (); - /* While in masked async, we may have not collected all the - pending events. Get them out now. */ - get_pending_events (); - sigprocmask (SIG_UNBLOCK, &mask, NULL); - } - else + + /* Always block before changing state. */ + sigprocmask (SIG_BLOCK, &mask, NULL); + + /* Set new state. */ + linux_nat_async_events_state = state; + + switch (state) { - /* Block target events. */ - sigprocmask (SIG_BLOCK, &mask, NULL); - linux_nat_async_events_enabled = 0; - /* Get events out of queue, and make them available to - queued_waitpid / my_waitpid. */ - pipe_to_local_event_queue (); + case sigchld_sync: + { + /* Block target events. */ + sigprocmask (SIG_BLOCK, &mask, NULL); + sigaction (SIGCHLD, &sync_sigchld_action, NULL); + /* Get events out of queue, and make them available to + queued_waitpid / my_waitpid. */ + pipe_to_local_event_queue (); + } + break; + case sigchld_async: + { + /* Unblock target events for async mode. */ + + sigprocmask (SIG_BLOCK, &mask, NULL); + + /* Put events we already waited on, in the pipe first, so + events are FIFO. */ + local_event_queue_to_pipe (); + /* While in masked async, we may have not collected all + the pending events. Get them out now. */ + get_pending_events (); + + /* Let'em come. */ + sigaction (SIGCHLD, &async_sigchld_action, NULL); + sigprocmask (SIG_UNBLOCK, &mask, NULL); + } + break; + case sigchld_default: + { + /* SIGCHLD default mode. */ + sigaction (SIGCHLD, &sigchld_default_action, NULL); + + /* Get events out of queue, and make them available to + queued_waitpid / my_waitpid. */ + pipe_to_local_event_queue (); + + /* Unblock SIGCHLD. */ + sigprocmask (SIG_UNBLOCK, &mask, NULL); + } + break; } } @@ -4143,14 +4189,14 @@ linux_nat_async (void (*callback) (enum inferior_event_type event_type, add_file_handler (linux_nat_event_pipe[0], linux_nat_async_file_handler, NULL); - linux_nat_async_events (1); + linux_nat_async_events (sigchld_async); } else { async_client_callback = callback; async_client_context = context; - linux_nat_async_events (0); + linux_nat_async_events (sigchld_sync); delete_file_handler (linux_nat_event_pipe[0]); } return; @@ -4166,21 +4212,15 @@ linux_nat_set_async_mode (int on) if (on) { gdb_assert (waitpid_queue == NULL); - sigaction (SIGCHLD, &async_sigchld_action, NULL); - if (pipe (linux_nat_event_pipe) == -1) internal_error (__FILE__, __LINE__, "creating event pipe failed."); - fcntl (linux_nat_event_pipe[0], F_SETFL, O_NONBLOCK); fcntl (linux_nat_event_pipe[1], F_SETFL, O_NONBLOCK); } else { - sigaction (SIGCHLD, &sync_sigchld_action, NULL); - drain_queued_events (-1); - linux_nat_num_queued_events = 0; close (linux_nat_event_pipe[0]); close (linux_nat_event_pipe[1]); @@ -4297,6 +4337,10 @@ Tells gdb whether to control the GNU/Linux inferior in asynchronous mode."), &maintenance_set_cmdlist, &maintenance_show_cmdlist); + /* Get the default SIGCHLD action. Used while forking an inferior + (see linux_nat_create_inferior/linux_nat_async_events). */ + sigaction (SIGCHLD, NULL, &sigchld_default_action); + /* Block SIGCHLD by default. Doing this early prevents it getting unblocked if an exception is thrown due to an error while the inferior is starting (sigsetjmp/siglongjmp). */ diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 9b7fdc53f82..32256e792fc 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2008-06-28 Pedro Alves + + * gdb.base/sigchld.c, gdb.base/sigchld.exp: New test. + 2008-06-28 Vladimir Prus * lib/mi-support.exp (mi_send_resuming_command_raw): Report pass. diff --git a/gdb/testsuite/gdb.base/sigchld.c b/gdb/testsuite/gdb.base/sigchld.c new file mode 100644 index 00000000000..7cee0417e2b --- /dev/null +++ b/gdb/testsuite/gdb.base/sigchld.c @@ -0,0 +1,37 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright 2008 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 . +*/ + +/* Check that GDB isn't messing the SIGCHLD mask while creating an + inferior. */ + +#include +#include + +int +main () +{ + sigset_t mask; + + sigemptyset (&mask); + sigprocmask (SIG_BLOCK, NULL, &mask); + + if (!sigismember (&mask, SIGCHLD)) + return 0; /* good, not blocked */ + else + return 1; /* bad, blocked */ +} diff --git a/gdb/testsuite/gdb.base/sigchld.exp b/gdb/testsuite/gdb.base/sigchld.exp new file mode 100644 index 00000000000..3151b2938bb --- /dev/null +++ b/gdb/testsuite/gdb.base/sigchld.exp @@ -0,0 +1,45 @@ +# Copyright (C) 2008 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 . + +# Check that GDB isn't messing the SIGCHLD mask while creating an +# inferior. + +if [target_info exists gdb,nosignals] { + verbose "Skipping sigchld.exp because of nosignals." + continue +} + +set testfile "sigchld" +set srcfile ${testfile}.c +set binfile ${objdir}/${subdir}/${testfile} + +if {[gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } { + return -1 +} + +gdb_exit +gdb_start +gdb_reinitialize_dir $srcdir/$subdir +gdb_load ${binfile} + +runto_main + +gdb_test "b [gdb_get_line_number "good, not blocked"]" \ + ".*Breakpoint .*sigchld.*" "set breakpoint at success exit" + +gdb_test "b [gdb_get_line_number "bad, blocked"]" \ + ".*Breakpoint .*sigchld.*" "set breakpoint at failure exit" + +gdb_test "continue" ".*good, not blocked.*" "SIGCHLD blocked in inferior" -- 2.30.2