[binutils-gdb] Introduce scoped_restore_signal
Pedro Alves
palves@sourceware.org
Thu Jun 17 15:22:53 GMT 2021
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=6a7f1c20e82c349a2d4c977a27319e895e8ca284
commit 6a7f1c20e82c349a2d4c977a27319e895e8ca284
Author: Pedro Alves <pedro@palves.net>
Date: Thu Jun 17 16:16:54 2021 +0100
Introduce scoped_restore_signal
We currently have scoped_restore_sigttou and scoped_restore_sigpipe
doing basically the same thing -- temporarily ignoring a specific
signal.
This patch introduce a scoped_restore_signal type that can be used for
both. This will become more important for the next patch which
changes how the signal-ignoring is implemented.
scoped_restore_sigpipe is a straight alias to
scoped_restore_signal<SIGPIPE> on systems that define SIGPIPE, and an
alias to scoped_restore_signal_nop (a no-op version of
scoped_restore_signal) otherwise.
scoped_restore_sigttou is not a straight alias because it wants to
check the job_control global.
gdb/ChangeLog:
yyyy-mm-dd Pedro Alves <pedro@palves.net>
* gdbsupport/scoped_ignore_signal.h: New.
* compile/compile.c: Include gdbsupport/scoped_ignore_signal.h
instead of <signal.h>. Don't include <unistd.h>.
(scoped_ignore_sigpipe): Remove.
* gdbsupport/scoped_ignore_sigttou.h: Include gdbsupport/scoped_ignore_signal.h
instead of <signal.h>. Don't include <unistd.h>.
(lazy_init): New.
(scoped_ignore_sigttou): Reimplement using scoped_ignore_signal
and lazy_init.
Change-Id: Ibb44d0bd705e96df03ef0787c77358a4a7b7086c
Diff:
---
gdb/ChangeLog | 12 +++++++
gdb/compile/compile.c | 29 +----------------
gdbsupport/scoped_ignore_signal.h | 64 ++++++++++++++++++++++++++++++++++++++
gdbsupport/scoped_ignore_sigttou.h | 55 +++++++++++++++++++++++++-------
4 files changed, 120 insertions(+), 40 deletions(-)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 63d7cf53b19..a56531e9f53 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,15 @@
+2021-06-17 Pedro Alves <pedro@palves.net>
+
+ * gdbsupport/scoped_ignore_signal.h: New.
+ * compile/compile.c: Include gdbsupport/scoped_ignore_signal.h
+ instead of <signal.h>. Don't include <unistd.h>.
+ (scoped_ignore_sigpipe): Remove.
+ * gdbsupport/scoped_ignore_sigttou.h: Include gdbsupport/scoped_ignore_signal.h
+ instead of <signal.h>. Don't include <unistd.h>.
+ (lazy_init): New.
+ (scoped_ignore_sigttou): Reimplement using scoped_ignore_signal
+ and lazy_init.
+
2021-06-17 Pedro Alves <pedro@palves.net>
* Makefile.in (HFILES_NO_SRCDIR): Remove inflow.h.
diff --git a/gdb/compile/compile.c b/gdb/compile/compile.c
index abbb72a393c..e815348ff07 100644
--- a/gdb/compile/compile.c
+++ b/gdb/compile/compile.c
@@ -43,7 +43,7 @@
#include "gdbsupport/gdb_optional.h"
#include "gdbsupport/gdb_unlinker.h"
#include "gdbsupport/pathstuff.h"
-#include <signal.h>
+#include "gdbsupport/scoped_ignore_signal.h"
@@ -634,33 +634,6 @@ print_callback (void *ignore, const char *message)
fputs_filtered (message, gdb_stderr);
}
-/* RAII class used to ignore SIGPIPE in a scope. */
-
-class scoped_ignore_sigpipe
-{
-public:
- scoped_ignore_sigpipe ()
- {
-#ifdef SIGPIPE
- m_osigpipe = signal (SIGPIPE, SIG_IGN);
-#endif
- }
-
- ~scoped_ignore_sigpipe ()
- {
-#ifdef SIGPIPE
- signal (SIGPIPE, m_osigpipe);
-#endif
- }
-
- DISABLE_COPY_AND_ASSIGN (scoped_ignore_sigpipe);
-
-private:
-#ifdef SIGPIPE
- sighandler_t m_osigpipe = NULL;
-#endif
-};
-
/* Process the compilation request. On success it returns the object
and source file names. On an error condition, error () is
called. */
diff --git a/gdbsupport/scoped_ignore_signal.h b/gdbsupport/scoped_ignore_signal.h
new file mode 100644
index 00000000000..cccd390529b
--- /dev/null
+++ b/gdbsupport/scoped_ignore_signal.h
@@ -0,0 +1,64 @@
+/* Support for ignoring signals.
+
+ Copyright (C) 2021 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 <http://www.gnu.org/licenses/>. */
+
+#ifndef SCOPED_IGNORE_SIGNAL_H
+#define SCOPED_IGNORE_SIGNAL_H
+
+#include <signal.h>
+
+/* RAII class used to ignore a signal in a scope. */
+
+template <int Sig>
+class scoped_ignore_signal
+{
+public:
+ scoped_ignore_signal ()
+ {
+ m_osig = signal (Sig, SIG_IGN);
+ }
+
+ ~scoped_ignore_signal ()
+ {
+ signal (Sig, m_osig);
+ }
+
+ DISABLE_COPY_AND_ASSIGN (scoped_ignore_signal);
+
+private:
+ sighandler_t m_osig = nullptr;
+};
+
+struct scoped_ignore_signal_nop
+{
+ /* Note, these can't both be "= default", because otherwise the
+ compiler warns that variables of this type are not used. */
+ scoped_ignore_signal_nop ()
+ {}
+ ~scoped_ignore_signal_nop ()
+ {}
+ DISABLE_COPY_AND_ASSIGN (scoped_ignore_signal_nop);
+};
+
+#ifdef SIGPIPE
+using scoped_ignore_sigpipe = scoped_ignore_signal<SIGPIPE>;
+#else
+using scoped_ignore_sigpipe = scoped_ignore_signal_nop;
+#endif
+
+#endif /* SCOPED_IGNORE_SIGNAL_H */
diff --git a/gdbsupport/scoped_ignore_sigttou.h b/gdbsupport/scoped_ignore_sigttou.h
index a31316460b4..1fc8f80d7fd 100644
--- a/gdbsupport/scoped_ignore_sigttou.h
+++ b/gdbsupport/scoped_ignore_sigttou.h
@@ -20,37 +20,68 @@
#ifndef SCOPED_IGNORE_SIGTTOU_H
#define SCOPED_IGNORE_SIGTTOU_H
-#include <unistd.h>
-#include <signal.h>
+#include "gdbsupport/scoped_ignore_signal.h"
#include "gdbsupport/job-control.h"
-/* RAII class used to ignore SIGTTOU in a scope. */
+#ifdef SIGTTOU
+
+/* Simple wrapper that allows lazy initialization / destruction of T.
+ Slightly more efficient than gdb::optional, because it doesn't
+ carry storage to track whether the object has been initialized. */
+template<typename T>
+class lazy_init
+{
+public:
+ void emplace ()
+ {
+ new (&m_u.obj) T ();
+ }
+
+ void reset ()
+ {
+ m_u.obj.~T ();
+ }
+
+private:
+ union u
+ {
+ /* Must define ctor/dtor if T has non-trivial ctor/dtor. */
+ u () {}
+ ~u () {}
+
+ T obj;
+ } m_u;
+};
+
+/* RAII class used to ignore SIGTTOU in a scope. This isn't simply
+ scoped_ignore_signal<SIGTTOU> because we want to check the
+ `job_control' global. */
class scoped_ignore_sigttou
{
public:
scoped_ignore_sigttou ()
{
-#ifdef SIGTTOU
if (job_control)
- m_osigttou = signal (SIGTTOU, SIG_IGN);
-#endif
+ m_ignore_signal.emplace ();
}
~scoped_ignore_sigttou ()
{
-#ifdef SIGTTOU
if (job_control)
- signal (SIGTTOU, m_osigttou);
-#endif
+ m_ignore_signal.reset ();
}
DISABLE_COPY_AND_ASSIGN (scoped_ignore_sigttou);
private:
-#ifdef SIGTTOU
- sighandler_t m_osigttou = NULL;
-#endif
+ lazy_init<scoped_ignore_signal<SIGTTOU>> m_ignore_signal;
};
+#else
+
+using scoped_ignore_sigttou = scoped_ignore_signal_nop;
+
+#endif
+
#endif /* SCOPED_IGNORE_SIGTTOU_H */
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