[RFC] Block all async signals used by gdb when initializing Guile
Hi.
When Guile initializes it will start several GC threads (libgc).
It's important that these threads block SIGCHLD (PR 17247).
This patch extends this to all async signals used by gdb.
One improvement on this patch would be to have event-top.c (or some
such) provide a routine that calls sigaddset for each appropriate
signal rather than defining the list in guile.c.
2015-08-29 Doug Evans xdj...@gmail.com
* guile/guile.c (_initialize_guile): Block all asynchronous signals
used by gdb when initializing Guile.
diff --git a/gdb/guile/guile.c b/gdb/guile/guile.c
index 4abf5c5..e9ef70b 100644
--- a/gdb/guile/guile.c
+++ b/gdb/guile/guile.c
@@ -847,7 +847,7 @@ _initialize_guile (void)
#if HAVE_GUILE
{
#ifdef HAVE_SIGPROCMASK
-sigset_t sigchld_mask, prev_mask;
+sigset_t guile_init_mask, prev_mask;
#endif
/* The Python support puts the C side in module _gdb, leaving the Python
@@ -867,9 +867,23 @@ _initialize_guile (void)
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);
+sigemptyset (guile_init_mask);
+sigaddset (guile_init_mask, SIGCHLD);
+/* Also block other asynchronous signals used by GDB. See event-top.c.
+ Really we want to block every signal here except for those specifically
+ used by Guile (e.g., GC threads), but this is safer for now. */
+sigaddset (guile_init_mask, SIGINT);
+sigaddset (guile_init_mask, SIGTERM);
+#ifdef SIGQUIT
+sigaddset (guile_init_mask, SIGQUIT);
+#endif
+#ifdef SIGHUP
+sigaddset (guile_init_mask, SIGHUP);
+#endif
+#ifdef SIGWINCH
+sigaddset (guile_init_mask, SIGWINCH);
+#endif
+sigprocmask (SIG_BLOCK, guile_init_mask, prev_mask);
#endif
/* scm_with_guile is the most portable way to initialize Guile.
Re: [RFC] Block all async signals used by gdb when initializing Guile
From: Doug Evans xdj...@gmail.com
cc: guile-devel@gnu.org
Date: Sat, 29 Aug 2015 10:22:11 -0700
--- a/gdb/guile/guile.c
+++ b/gdb/guile/guile.c
@@ -847,7 +847,7 @@ _initialize_guile (void)
#if HAVE_GUILE
{
#ifdef HAVE_SIGPROCMASK
-sigset_t sigchld_mask, prev_mask;
+sigset_t guile_init_mask, prev_mask;
#endif
/* The Python support puts the C side in module _gdb, leaving the
Python
@@ -867,9 +867,23 @@ _initialize_guile (void)
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);
+sigemptyset (guile_init_mask);
+sigaddset (guile_init_mask, SIGCHLD);
+/* Also block other asynchronous signals used by GDB. See event-top.c.
+ Really we want to block every signal here except for those
specifically
+ used by Guile (e.g., GC threads), but this is safer for now. */
+sigaddset (guile_init_mask, SIGINT);
+sigaddset (guile_init_mask, SIGTERM);
+#ifdef SIGQUIT
+sigaddset (guile_init_mask, SIGQUIT);
+#endif
+#ifdef SIGHUP
+sigaddset (guile_init_mask, SIGHUP);
+#endif
+#ifdef SIGWINCH
+sigaddset (guile_init_mask, SIGWINCH);
+#endif
+sigprocmask (SIG_BLOCK, guile_init_mask, prev_mask);
#endif
What about platforms that don't have sigprocmask, but do have SIGINT?
Don't we want to block SIGINT on those platforms?
Re: [RFC] Block all async signals used by gdb when initializing Guile
On Sat, Aug 29, 2015 at 1:16 PM, Eli Zaretskii e...@gnu.org wrote: Date: Sat, 29 Aug 2015 12:20:24 -0700 From: Doug Evans xdj...@gmail.com Cc: gdb-patc...@sourceware.org gdb-patc...@sourceware.org, guile-devel guile-devel@gnu.org What about platforms that don't have sigprocmask, but do have SIGINT? Don't we want to block SIGINT on those platforms? Do they have threads They might. (The only way I've succeeded to have a working Guile on Windows was to disable threads, but I hope that bug will be fixed one day.) and how does one block SIGINT on those platforms? With a call to 'signal', I guess. I'm guessing that won't work here, we'll need something else. The issue is we need the threads that guile starts to have these signals blocked. Then after guile init returns we unblock the signals.
Re: [RFC] Block all async signals used by gdb when initializing Guile
Date: Sat, 29 Aug 2015 13:39:55 -0700 From: Doug Evans xdj...@gmail.com Cc: gdb-patc...@sourceware.org gdb-patc...@sourceware.org, guile-devel guile-devel@gnu.org On Sat, Aug 29, 2015 at 1:16 PM, Eli Zaretskii e...@gnu.org wrote: Date: Sat, 29 Aug 2015 12:20:24 -0700 From: Doug Evans xdj...@gmail.com Cc: gdb-patc...@sourceware.org gdb-patc...@sourceware.org, guile-devel guile-devel@gnu.org What about platforms that don't have sigprocmask, but do have SIGINT? Don't we want to block SIGINT on those platforms? Do they have threads They might. (The only way I've succeeded to have a working Guile on Windows was to disable threads, but I hope that bug will be fixed one day.) and how does one block SIGINT on those platforms? With a call to 'signal', I guess. I'm guessing that won't work here, we'll need something else. I don't understand why. Can you explain? Maybe I'm missing something. The issue is we need the threads that guile starts to have these signals blocked. Then after guile init returns we unblock the signals. Inhibit SIGINT ech time before calling Guile and restore it after Guile returns. Wouldn't that do what you want?
Re: [RFC] Block all async signals used by gdb when initializing Guile
Date: Sat, 29 Aug 2015 23:04:02 +0200 (CEST) From: Mark Kettenis mark.kette...@xs4all.nl CC: e...@gnu.org, gdb-patc...@sourceware.org, guile-devel@gnu.org I suppose blocking these in the threads that guile starts is necessary because that is the only way to guarantee that those signals will be delivered to the main gdb thread on POSIX systems. On Windows you probably need to do something completely different. I might be missing something, because I don't see why.
