[PATCH v4 01/10] Add handle_eintr to wrap EINTR handling in syscalls
Kamil Rytarowski
n54@gmx.com
Tue Sep 8 12:36:28 GMT 2020
gdbsupport/ChangeLog:
* eintr.h: New file.
---
gdbsupport/ChangeLog | 4 +++
gdbsupport/eintr.h | 67 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 71 insertions(+)
create mode 100644 gdbsupport/eintr.h
diff --git a/gdbsupport/ChangeLog b/gdbsupport/ChangeLog
index a1960537384..d26000e36ac 100644
--- a/gdbsupport/ChangeLog
+++ b/gdbsupport/ChangeLog
@@ -1,3 +1,7 @@
+2020-09-04 Kamil Rytarowski <n54@gmx.com>
+
+ * eintr.h: New file.
+
2020-08-13 Simon Marchi <simon.marchi@polymtl.ca>
* selftest.h (run_tests): Change parameter to array_view.
diff --git a/gdbsupport/eintr.h b/gdbsupport/eintr.h
new file mode 100644
index 00000000000..64ff5940b75
--- /dev/null
+++ b/gdbsupport/eintr.h
@@ -0,0 +1,67 @@
+/* Utility for handling interrupted syscalls by signals.
+
+ Copyright (C) 2020 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 GDBSUPPORT_EINTR_H
+#define GDBSUPPORT_EINTR_H
+
+#include <cerrno>
+
+namespace gdb
+{
+/* Repeat a system call interrupted with a signal.
+
+ A utility for handling interrupted syscalls, which return with error
+ and set the errno to EINTR. The interrupted syscalls can be repeated,
+ until successful completion. This utility avoids wrapping code with
+ manual checks for such errors which are highly repetitive.
+
+ For example, with:
+
+ ssize_t ret;
+ do
+ {
+ errno = 0;
+ ret = ::write (pipe[1], "+", 1);
+ }
+ while (ret == -1 && errno == EINTR);
+
+ You could wrap it by writing the wrapped form:
+
+ ssize_t ret = gdb::handle_eintr<ssize_t> (-1, ::write, pipe[1], "+", 1);
+
+ The RET typename specifies the return type of the wrapped system call, which
+ is typically int or ssize_t. The R argument specifies the failure value
+ indicating the interrupted syscall when calling the F function with
+ the A... arguments. */
+
+template <typename Ret, typename Fun, typename... Args>
+inline Ret handle_eintr (const Ret &R, const Fun &F, const Args &... A)
+{
+ Ret ret;
+ do
+ {
+ errno = 0;
+ ret = F (A...);
+ }
+ while (ret == R && errno == EINTR);
+ return ret;
+}
+}
+
+#endif /* GDBSUPPORT_EINTR_H */
--
2.28.0
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