From 21987b9c060033d367abc50c29f786df4c21b10c Mon Sep 17 00:00:00 2001 From: Tom Tromey Date: Sun, 29 Sep 2019 08:50:15 -0600 Subject: [PATCH] Add RAII class for blocking gdb signals This adds configury support and an RAII class that can be used to temporarily block signals that are used by gdb. (This class is not used in this patch, but it split out for easier review.) The idea of this patch is that these signals should only be delivered to the main thread. So, when creating a background thread, they are temporarily blocked; the blocked state is inherited by the new thread. The sigprocmask man page says: The use of sigprocmask() is unspecified in a multithreaded process; see pthread_sigmask(3). This patch changes gdb to use pthread_sigmask when appropriate, by introducing a convenience define. I've updated gdbserver as well, because I had to touch gdbsupport, and because the threading patches will make it link against the thread library. I chose not to touch the NTO code, because I don't know anything about that platform and because I cannot test it. Finally, this modifies an existing spot in the Guile layer to use the new facility. gdb/ChangeLog 2019-11-26 Tom Tromey * gdbsupport/signals-state-save-restore.c (original_signal_mask): Remove comment. (save_original_signals_state, restore_original_signals_state): Use gdb_sigmask. * linux-nat.c (block_child_signals, restore_child_signals_mask) (_initialize_linux_nat): Use gdb_sigmask. * guile/guile.c (_initialize_guile): Use block_signals. * Makefile.in (HFILES_NO_SRCDIR): Add gdb-sigmask.h. * gdbsupport/gdb-sigmask.h: New file. * event-top.c (async_sigtstp_handler): Use gdb_sigmask. * cp-support.c (gdb_demangle): Use gdb_sigmask. * gdbsupport/common.m4 (GDB_AC_COMMON): Check for pthread_sigmask. * configure, config.in: Rebuild. * gdbsupport/block-signals.h: New file. gdb/gdbserver/ChangeLog 2019-11-26 Tom Tromey * remote-utils.c (block_unblock_async_io): Use gdb_sigmask. * linux-low.c (linux_wait_for_event_filtered, linux_async): Use gdb_sigmask. * configure, config.in: Rebuild. Change-Id: If3f37dc57dd859c226e9e4d79458a0514746e8c6 --- gdb/ChangeLog | 18 +++ gdb/Makefile.in | 1 + gdb/config.in | 3 + gdb/configure | 82 +++++++++++++ gdb/cp-support.c | 3 +- gdb/event-top.c | 3 +- gdb/gdbserver/ChangeLog | 7 ++ gdb/gdbserver/config.in | 3 + gdb/gdbserver/configure | 128 ++++++++++++++++++++ gdb/gdbserver/linux-low.c | 17 +-- gdb/gdbserver/remote-utils.c | 3 +- gdb/gdbsupport/block-signals.h | 67 ++++++++++ gdb/gdbsupport/common.m4 | 5 + gdb/gdbsupport/gdb-sigmask.h | 45 +++++++ gdb/gdbsupport/signals-state-save-restore.c | 9 +- gdb/guile/guile.c | 28 ++--- gdb/linux-nat.c | 7 +- 17 files changed, 391 insertions(+), 38 deletions(-) create mode 100644 gdb/gdbsupport/block-signals.h create mode 100644 gdb/gdbsupport/gdb-sigmask.h diff --git a/gdb/ChangeLog b/gdb/ChangeLog index ca9290180cc..9d4fe360b27 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,21 @@ +2019-11-26 Tom Tromey + + * gdbsupport/signals-state-save-restore.c (original_signal_mask): + Remove comment. + (save_original_signals_state, restore_original_signals_state): Use + gdb_sigmask. + * linux-nat.c (block_child_signals, restore_child_signals_mask) + (_initialize_linux_nat): Use gdb_sigmask. + * guile/guile.c (_initialize_guile): Use block_signals. + * Makefile.in (HFILES_NO_SRCDIR): Add gdb-sigmask.h. + * gdbsupport/gdb-sigmask.h: New file. + * event-top.c (async_sigtstp_handler): Use gdb_sigmask. + * cp-support.c (gdb_demangle): Use gdb_sigmask. + * gdbsupport/common.m4 (GDB_AC_COMMON): Check for + pthread_sigmask. + * configure, config.in: Rebuild. + * gdbsupport/block-signals.h: New file. + 2019-11-26 Tom Tromey * acinclude.m4: Include ax_pthread.m4. diff --git a/gdb/Makefile.in b/gdb/Makefile.in index 404f559baef..8d248ae7802 100644 --- a/gdb/Makefile.in +++ b/gdb/Makefile.in @@ -1473,6 +1473,7 @@ HFILES_NO_SRCDIR = \ gdbsupport/fileio.h \ gdbsupport/format.h \ gdbsupport/gdb-dlfcn.h \ + gdbsupport/gdb-sigmask.h \ gdbsupport/gdb_assert.h \ gdbsupport/gdb_binary_search.h \ gdbsupport/gdb_tilde_expand.h \ diff --git a/gdb/config.in b/gdb/config.in index f20693b05d8..61e63e23300 100644 --- a/gdb/config.in +++ b/gdb/config.in @@ -342,6 +342,9 @@ /* Have PTHREAD_PRIO_INHERIT. */ #undef HAVE_PTHREAD_PRIO_INHERIT +/* Define to 1 if you have the `pthread_sigmask' function. */ +#undef HAVE_PTHREAD_SIGMASK + /* Define to 1 if you have the `ptrace64' function. */ #undef HAVE_PTRACE64 diff --git a/gdb/configure b/gdb/configure index 50164ac8a4a..dd936d247e3 100755 --- a/gdb/configure +++ b/gdb/configure @@ -2520,6 +2520,73 @@ fi as_fn_set_status $ac_retval } # ac_fn_cxx_try_link + +# ac_fn_cxx_check_func LINENO FUNC VAR +# ------------------------------------ +# Tests whether FUNC exists, setting the cache variable VAR accordingly +ac_fn_cxx_check_func () +{ + as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack + { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2" >&5 +$as_echo_n "checking for $2... " >&6; } +if eval \${$3+:} false; then : + $as_echo_n "(cached) " >&6 +else + cat confdefs.h - <<_ACEOF >conftest.$ac_ext +/* end confdefs.h. */ +/* Define $2 to an innocuous variant, in case declares $2. + For example, HP-UX 11i declares gettimeofday. */ +#define $2 innocuous_$2 + +/* System header to define __stub macros and hopefully few prototypes, + which can conflict with char $2 (); below. + Prefer to if __STDC__ is defined, since + exists even on freestanding compilers. */ + +#ifdef __STDC__ +# include +#else +# include +#endif + +#undef $2 + +/* Override any GCC internal prototype to avoid an error. + Use char because int might match the return type of a GCC + builtin and then its argument prototype would still apply. */ +#ifdef __cplusplus +extern "C" +#endif +char $2 (); +/* The GNU C library defines this for functions which it implements + to always fail with ENOSYS. Some functions are actually named + something starting with __ and the normal name is an alias. */ +#if defined __stub_$2 || defined __stub___$2 +choke me +#endif + +int +main () +{ +return $2 (); + ; + return 0; +} +_ACEOF +if ac_fn_cxx_try_link "$LINENO"; then : + eval "$3=yes" +else + eval "$3=no" +fi +rm -f core conftest.err conftest.$ac_objext \ + conftest$ac_exeext conftest.$ac_ext +fi +eval ac_res=\$$3 + { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5 +$as_echo "$ac_res" >&6; } + eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno + +} # ac_fn_cxx_check_func cat >config.log <<_ACEOF This file contains any messages produced by compilers while running configure, to aid debugging if configure makes a mistake. @@ -14263,6 +14330,21 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext fi { $as_echo "$as_me:${as_lineno-$LINENO}: result: $gdb_cv_cxx_std_thread" >&5 $as_echo "$gdb_cv_cxx_std_thread" >&6; } + + # This check must be here, while LIBS includes any necessary + # threading library. + for ac_func in pthread_sigmask +do : + ac_fn_cxx_check_func "$LINENO" "pthread_sigmask" "ac_cv_func_pthread_sigmask" +if test "x$ac_cv_func_pthread_sigmask" = xyes; then : + cat >>confdefs.h <<_ACEOF +#define HAVE_PTHREAD_SIGMASK 1 +_ACEOF + +fi +done + + LIBS="$save_LIBS" CXXFLAGS="$save_CXXFLAGS" fi diff --git a/gdb/cp-support.c b/gdb/cp-support.c index 90a8d2ece04..f1ddc74976d 100644 --- a/gdb/cp-support.c +++ b/gdb/cp-support.c @@ -37,6 +37,7 @@ #include "gdbsupport/gdb_setjmp.h" #include "safe-ctype.h" #include "gdbsupport/selftest.h" +#include "gdbsupport/gdb-sigmask.h" #define d_left(dc) (dc)->u.s_binary.left #define d_right(dc) (dc)->u.s_binary.right @@ -1572,7 +1573,7 @@ gdb_demangle (const char *name, int options) sigset_t segv_sig_set; sigemptyset (&segv_sig_set); sigaddset (&segv_sig_set, SIGSEGV); - sigprocmask (SIG_UNBLOCK, &segv_sig_set, NULL); + gdb_sigmask (SIG_UNBLOCK, &segv_sig_set, NULL); #endif if (!error_reported) diff --git a/gdb/event-top.c b/gdb/event-top.c index 0396dbcc52d..6c6e0ff3baa 100644 --- a/gdb/event-top.c +++ b/gdb/event-top.c @@ -40,6 +40,7 @@ #include "gdbsupport/buffer.h" #include "ser-event.h" #include "gdb_select.h" +#include "gdbsupport/gdb-sigmask.h" /* readline include files. */ #include "readline/readline.h" @@ -1127,7 +1128,7 @@ async_sigtstp_handler (gdb_client_data arg) sigset_t zero; sigemptyset (&zero); - sigprocmask (SIG_SETMASK, &zero, 0); + gdb_sigmask (SIG_SETMASK, &zero, 0); } #elif HAVE_SIGSETMASK sigsetmask (0); diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog index eee4b818a25..00b0a0df025 100644 --- a/gdb/gdbserver/ChangeLog +++ b/gdb/gdbserver/ChangeLog @@ -1,3 +1,10 @@ +2019-11-26 Tom Tromey + + * remote-utils.c (block_unblock_async_io): Use gdb_sigmask. + * linux-low.c (linux_wait_for_event_filtered, linux_async): Use + gdb_sigmask. + * configure, config.in: Rebuild. + 2019-11-26 Tom Tromey * Makefile.in (PTHREAD_CFLAGS, PTHREAD_LIBS): New variables. diff --git a/gdb/gdbserver/config.in b/gdb/gdbserver/config.in index 4276bce9af0..3027ffa1b1c 100644 --- a/gdb/gdbserver/config.in +++ b/gdb/gdbserver/config.in @@ -195,6 +195,9 @@ /* Have PTHREAD_PRIO_INHERIT. */ #undef HAVE_PTHREAD_PRIO_INHERIT +/* Define to 1 if you have the `pthread_sigmask' function. */ +#undef HAVE_PTHREAD_SIGMASK + /* Define if the target supports PTRACE_GETFPXREGS for extended register access. */ #undef HAVE_PTRACE_GETFPXREGS diff --git a/gdb/gdbserver/configure b/gdb/gdbserver/configure index 882c1922a1e..8d34a6c3059 100755 --- a/gdb/gdbserver/configure +++ b/gdb/gdbserver/configure @@ -1972,6 +1972,119 @@ $as_echo "$ac_res" >&6; } } # ac_fn_c_check_decl +# ac_fn_cxx_try_link LINENO +# ------------------------- +# Try to link conftest.$ac_ext, and return whether this succeeded. +ac_fn_cxx_try_link () +{ + as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack + rm -f conftest.$ac_objext conftest$ac_exeext + if { { ac_try="$ac_link" +case "(($ac_try" in + *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;; + *) ac_try_echo=$ac_try;; +esac +eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\"" +$as_echo "$ac_try_echo"; } >&5 + (eval "$ac_link") 2>conftest.err + ac_status=$? + if test -s conftest.err; then + grep -v '^ *+' conftest.err >conftest.er1 + cat conftest.er1 >&5 + mv -f conftest.er1 conftest.err + fi + $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5 + test $ac_status = 0; } && { + test -z "$ac_cxx_werror_flag" || + test ! -s conftest.err + } && test -s conftest$ac_exeext && { + test "$cross_compiling" = yes || + test -x conftest$ac_exeext + }; then : + ac_retval=0 +else + $as_echo "$as_me: failed program was:" >&5 +sed 's/^/| /' conftest.$ac_ext >&5 + + ac_retval=1 +fi + # Delete the IPA/IPO (Inter Procedural Analysis/Optimization) information + # created by the PGI compiler (conftest_ipa8_conftest.oo), as it would + # interfere with the next link command; also delete a directory that is + # left behind by Apple's compiler. We do this before executing the actions. + rm -rf conftest.dSYM conftest_ipa8_conftest.oo + eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno + as_fn_set_status $ac_retval + +} # ac_fn_cxx_try_link + +# ac_fn_cxx_check_func LINENO FUNC VAR +# ------------------------------------ +# Tests whether FUNC exists, setting the cache variable VAR accordingly +ac_fn_cxx_check_func () +{ + as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack + { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2" >&5 +$as_echo_n "checking for $2... " >&6; } +if eval \${$3+:} false; then : + $as_echo_n "(cached) " >&6 +else + cat confdefs.h - <<_ACEOF >conftest.$ac_ext +/* end confdefs.h. */ +/* Define $2 to an innocuous variant, in case declares $2. + For example, HP-UX 11i declares gettimeofday. */ +#define $2 innocuous_$2 + +/* System header to define __stub macros and hopefully few prototypes, + which can conflict with char $2 (); below. + Prefer to if __STDC__ is defined, since + exists even on freestanding compilers. */ + +#ifdef __STDC__ +# include +#else +# include +#endif + +#undef $2 + +/* Override any GCC internal prototype to avoid an error. + Use char because int might match the return type of a GCC + builtin and then its argument prototype would still apply. */ +#ifdef __cplusplus +extern "C" +#endif +char $2 (); +/* The GNU C library defines this for functions which it implements + to always fail with ENOSYS. Some functions are actually named + something starting with __ and the normal name is an alias. */ +#if defined __stub_$2 || defined __stub___$2 +choke me +#endif + +int +main () +{ +return $2 (); + ; + return 0; +} +_ACEOF +if ac_fn_cxx_try_link "$LINENO"; then : + eval "$3=yes" +else + eval "$3=no" +fi +rm -f core conftest.err conftest.$ac_objext \ + conftest$ac_exeext conftest.$ac_ext +fi +eval ac_res=\$$3 + { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5 +$as_echo "$ac_res" >&6; } + eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno + +} # ac_fn_cxx_check_func + # ac_fn_c_compute_int LINENO EXPR VAR INCLUDES # -------------------------------------------- # Tries to find the compile-time value of EXPR in a program that includes @@ -7609,6 +7722,21 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext fi { $as_echo "$as_me:${as_lineno-$LINENO}: result: $gdb_cv_cxx_std_thread" >&5 $as_echo "$gdb_cv_cxx_std_thread" >&6; } + + # This check must be here, while LIBS includes any necessary + # threading library. + for ac_func in pthread_sigmask +do : + ac_fn_cxx_check_func "$LINENO" "pthread_sigmask" "ac_cv_func_pthread_sigmask" +if test "x$ac_cv_func_pthread_sigmask" = xyes; then : + cat >>confdefs.h <<_ACEOF +#define HAVE_PTHREAD_SIGMASK 1 +_ACEOF + +fi +done + + LIBS="$save_LIBS" CXXFLAGS="$save_CXXFLAGS" fi diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c index f34811cda2a..688a3954028 100644 --- a/gdb/gdbserver/linux-low.c +++ b/gdb/gdbserver/linux-low.c @@ -50,6 +50,7 @@ #include "gdbsupport/common-inferior.h" #include "nat/fork-inferior.h" #include "gdbsupport/environ.h" +#include "gdbsupport/gdb-sigmask.h" #include "gdbsupport/scoped_restore.h" #ifndef ELFMAG0 /* Don't include here. If it got included by gdb_proc_service.h @@ -2689,7 +2690,7 @@ linux_wait_for_event_filtered (ptid_t wait_ptid, ptid_t filter_ptid, /* Make sure SIGCHLD is blocked until the sigsuspend below. Block all signals while here. */ sigfillset (&block_mask); - sigprocmask (SIG_BLOCK, &block_mask, &prev_mask); + gdb_sigmask (SIG_BLOCK, &block_mask, &prev_mask); /* Always pull all events out of the kernel. We'll randomly select an event LWP out of all that have events, to prevent @@ -2775,7 +2776,7 @@ linux_wait_for_event_filtered (ptid_t wait_ptid, ptid_t filter_ptid, { if (debug_threads) debug_printf ("LLW: exit (no unwaited-for LWP)\n"); - sigprocmask (SIG_SETMASK, &prev_mask, NULL); + gdb_sigmask (SIG_SETMASK, &prev_mask, NULL); return -1; } @@ -2785,7 +2786,7 @@ linux_wait_for_event_filtered (ptid_t wait_ptid, ptid_t filter_ptid, if (debug_threads) debug_printf ("WNOHANG set, no event found\n"); - sigprocmask (SIG_SETMASK, &prev_mask, NULL); + gdb_sigmask (SIG_SETMASK, &prev_mask, NULL); return 0; } @@ -2794,11 +2795,11 @@ linux_wait_for_event_filtered (ptid_t wait_ptid, ptid_t filter_ptid, debug_printf ("sigsuspend'ing\n"); sigsuspend (&prev_mask); - sigprocmask (SIG_SETMASK, &prev_mask, NULL); + gdb_sigmask (SIG_SETMASK, &prev_mask, NULL); goto retry; } - sigprocmask (SIG_SETMASK, &prev_mask, NULL); + gdb_sigmask (SIG_SETMASK, &prev_mask, NULL); current_thread = event_thread; @@ -6215,7 +6216,7 @@ linux_async (int enable) sigemptyset (&mask); sigaddset (&mask, SIGCHLD); - sigprocmask (SIG_BLOCK, &mask, NULL); + gdb_sigmask (SIG_BLOCK, &mask, NULL); if (enable) { @@ -6223,7 +6224,7 @@ linux_async (int enable) { linux_event_pipe[0] = -1; linux_event_pipe[1] = -1; - sigprocmask (SIG_UNBLOCK, &mask, NULL); + gdb_sigmask (SIG_UNBLOCK, &mask, NULL); warning ("creating event pipe failed."); return previous; @@ -6249,7 +6250,7 @@ linux_async (int enable) linux_event_pipe[1] = -1; } - sigprocmask (SIG_UNBLOCK, &mask, NULL); + gdb_sigmask (SIG_UNBLOCK, &mask, NULL); } return previous; diff --git a/gdb/gdbserver/remote-utils.c b/gdb/gdbserver/remote-utils.c index d7da4b7aed2..c7f97f3fbef 100644 --- a/gdb/gdbserver/remote-utils.c +++ b/gdb/gdbserver/remote-utils.c @@ -28,6 +28,7 @@ #include "gdbsupport/rsp-low.h" #include "gdbsupport/netstuff.h" #include "gdbsupport/filestuff.h" +#include "gdbsupport/gdb-sigmask.h" #include #if HAVE_SYS_IOCTL_H #include @@ -807,7 +808,7 @@ block_unblock_async_io (int block) sigemptyset (&sigio_set); sigaddset (&sigio_set, SIGIO); - sigprocmask (block ? SIG_BLOCK : SIG_UNBLOCK, &sigio_set, NULL); + gdb_sigmask (block ? SIG_BLOCK : SIG_UNBLOCK, &sigio_set, NULL); #endif } diff --git a/gdb/gdbsupport/block-signals.h b/gdb/gdbsupport/block-signals.h new file mode 100644 index 00000000000..3f11aba1f8f --- /dev/null +++ b/gdb/gdbsupport/block-signals.h @@ -0,0 +1,67 @@ +/* Block signals used by gdb + + Copyright (C) 2019 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 . */ + +#ifndef GDBSUPPORT_BLOCK_SIGNALS_H +#define GDBSUPPORT_BLOCK_SIGNALS_H + +#include + +#include "gdbsupport/gdb-sigmask.h" + +namespace gdb +{ + +/* This is an RAII class that temporarily blocks the signals needed by + gdb. This can be used before starting a new thread to ensure that + this thread starts with the appropriate signals blocked. */ +class block_signals +{ +public: + block_signals () + { +#ifdef HAVE_SIGPROCMASK + sigset_t mask; + sigemptyset (&mask); + sigaddset (&mask, SIGINT); + sigaddset (&mask, SIGCHLD); + sigaddset (&mask, SIGALRM); + sigaddset (&mask, SIGWINCH); + gdb_sigmask (SIG_BLOCK, &mask, &m_old_mask); +#endif + } + + ~block_signals () + { +#ifdef HAVE_SIGPROCMASK + gdb_sigmask (SIG_SETMASK, &m_old_mask, nullptr); +#endif + } + + DISABLE_COPY_AND_ASSIGN (block_signals); + +private: + +#ifdef HAVE_SIGPROCMASK + sigset_t m_old_mask; +#endif +}; + +} + +#endif /* GDBSUPPORT_BLOCK_SIGNALS_H */ diff --git a/gdb/gdbsupport/common.m4 b/gdb/gdbsupport/common.m4 index f813c04fd3f..e993b202487 100644 --- a/gdb/gdbsupport/common.m4 +++ b/gdb/gdbsupport/common.m4 @@ -54,6 +54,11 @@ AC_DEFUN([GDB_AC_COMMON], [ [[std::thread t(callback);]])], gdb_cv_cxx_std_thread=yes, gdb_cv_cxx_std_thread=no)]) + + # This check must be here, while LIBS includes any necessary + # threading library. + AC_CHECK_FUNCS([pthread_sigmask]) + LIBS="$save_LIBS" CXXFLAGS="$save_CXXFLAGS" fi diff --git a/gdb/gdbsupport/gdb-sigmask.h b/gdb/gdbsupport/gdb-sigmask.h new file mode 100644 index 00000000000..08ad9734e5b --- /dev/null +++ b/gdb/gdbsupport/gdb-sigmask.h @@ -0,0 +1,45 @@ +/* sigprocmask wrapper for gdb + + Copyright (C) 2019 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 . */ + +#ifndef GDBSUPPORT_GDB_SIGMASK_H +#define GDBSUPPORT_GDB_SIGMASK_H + +#include + +#ifdef HAVE_SIGPROCMASK + +#ifdef HAVE_PTHREAD_SIGMASK +#define gdb_sigmask pthread_sigmask +#else +#define gdb_sigmask sigprocmask +#endif + +#else /* HAVE_SIGPROCMASK */ + +/* Other code checks HAVE_SIGPROCMASK, but if there happened to be a + system that only had pthread_sigmask, we could still use it with + some extra changes. */ +#ifdef HAVE_PTHREAD_SIGMASK +#error pthead_sigmask available without sigprocmask - please report +#endif + +#endif /* HAVE_SIGPROCMASK */ + + +#endif /* GDBSUPPORT_GDB_SIGMASK_H */ diff --git a/gdb/gdbsupport/signals-state-save-restore.c b/gdb/gdbsupport/signals-state-save-restore.c index c66d2ddc62f..25a82209768 100644 --- a/gdb/gdbsupport/signals-state-save-restore.c +++ b/gdb/gdbsupport/signals-state-save-restore.c @@ -17,6 +17,7 @@ #include "common-defs.h" #include "signals-state-save-restore.h" +#include "gdbsupport/gdb-sigmask.h" #include @@ -25,10 +26,6 @@ #ifdef HAVE_SIGACTION static struct sigaction original_signal_actions[NSIG]; -/* Note that we use sigprocmask without worrying about threads because - the save/restore functions are called either from main, or after a - fork. In both cases, we know the calling process is single - threaded. */ static sigset_t original_signal_mask; #endif @@ -41,7 +38,7 @@ save_original_signals_state (bool quiet) int i; int res; - res = sigprocmask (0, NULL, &original_signal_mask); + res = gdb_sigmask (0, NULL, &original_signal_mask); if (res == -1) perror_with_name (("sigprocmask")); @@ -110,7 +107,7 @@ restore_original_signals_state (void) perror_with_name (("sigaction")); } - res = sigprocmask (SIG_SETMASK, &original_signal_mask, NULL); + res = gdb_sigmask (SIG_SETMASK, &original_signal_mask, NULL); if (res == -1) perror_with_name (("sigprocmask")); #endif diff --git a/gdb/guile/guile.c b/gdb/guile/guile.c index 55929f44551..d745c56ec68 100644 --- a/gdb/guile/guile.c +++ b/gdb/guile/guile.c @@ -36,6 +36,7 @@ #include "guile-internal.h" #endif #include +#include "gdbsupport/block-signals.h" /* The Guile version we're using. We *could* use the macros in libguile/version.h but that would preclude @@ -798,10 +799,6 @@ _initialize_guile (void) #if HAVE_GUILE { -#ifdef HAVE_SIGPROCMASK - sigset_t sigchld_mask, prev_mask; -#endif - /* The Python support puts the C side in module "_gdb", leaving the Python side to define module "gdb" which imports "_gdb". There is evidently no similar convention in Guile so we skip this. */ @@ -813,25 +810,20 @@ _initialize_guile (void) scm_set_automatic_finalization_enabled (0); #endif -#ifdef HAVE_SIGPROCMASK - /* Before we initialize Guile, block SIGCHLD. + /* Before we initialize Guile, block signals needed by gdb + (especially SIGCHLD). This is done so that all threads created during Guile initialization have SIGCHLD blocked. PR 17247. Really libgc and Guile should do this, but we need to work with libgc 7.4.x. */ - sigemptyset (&sigchld_mask); - sigaddset (&sigchld_mask, SIGCHLD); - sigprocmask (SIG_BLOCK, &sigchld_mask, &prev_mask); -#endif - - /* scm_with_guile is the most portable way to initialize Guile. - Plus we need to initialize the Guile support while in Guile mode - (e.g., called from within a call to scm_with_guile). */ - scm_with_guile (call_initialize_gdb_module, NULL); + { + gdb::block_signals blocker; -#ifdef HAVE_SIGPROCMASK - sigprocmask (SIG_SETMASK, &prev_mask, NULL); -#endif + /* scm_with_guile is the most portable way to initialize Guile. + Plus we need to initialize the Guile support while in Guile mode + (e.g., called from within a call to scm_with_guile). */ + scm_with_guile (call_initialize_gdb_module, NULL); + } /* Set Guile's backtrace to match the "set guile print-stack" default. [N.B. The two settings are still separate.] diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c index 2a63ac727d3..465b2acd946 100644 --- a/gdb/linux-nat.c +++ b/gdb/linux-nat.c @@ -67,6 +67,7 @@ #include "nat/linux-namespaces.h" #include "gdbsupport/fileio.h" #include "gdbsupport/scope-exit.h" +#include "gdbsupport/gdb-sigmask.h" /* This comment documents high-level logic of this file. @@ -764,7 +765,7 @@ block_child_signals (sigset_t *prev_mask) if (!sigismember (&blocked_mask, SIGCHLD)) sigaddset (&blocked_mask, SIGCHLD); - sigprocmask (SIG_BLOCK, &blocked_mask, prev_mask); + gdb_sigmask (SIG_BLOCK, &blocked_mask, prev_mask); } /* Restore child signals mask, previously returned by @@ -773,7 +774,7 @@ block_child_signals (sigset_t *prev_mask) static void restore_child_signals_mask (sigset_t *prev_mask) { - sigprocmask (SIG_SETMASK, prev_mask, NULL); + gdb_sigmask (SIG_SETMASK, prev_mask, NULL); } /* Mask of signals to pass directly to the inferior. */ @@ -4564,7 +4565,7 @@ Enables printf debugging output."), sigaction (SIGCHLD, &sigchld_action, NULL); /* Make sure we don't block SIGCHLD during a sigsuspend. */ - sigprocmask (SIG_SETMASK, NULL, &suspend_mask); + gdb_sigmask (SIG_SETMASK, NULL, &suspend_mask); sigdelset (&suspend_mask, SIGCHLD); sigemptyset (&blocked_mask); -- 2.30.2