From 21987b9c060033d367abc50c29f786df4c21b10c Mon Sep 17 00:00:00 2001 From: Tom Tromey Date: Sun, 29 Sep 2019 08:50:15 -0600 Subject: 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/configure | 82 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 82 insertions(+) (limited to 'gdb/configure') diff --git a/gdb/configure b/gdb/configure index 50164ac..dd936d2 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 -- cgit v1.1