[1/6] Introduce scoped_pipe.h
Commit Message
This simple patch introduces gdbsupport/scoped_pipe.h, which is based
on gdbsupport/scoped_fd.h. When the object is instantiated, a pipe is
created using 'gdb_pipe_cloexec'. There are two methods (get_read_end
and get_write_end) that allow the user to obtain the read/write ends
of the pipe (no more messing with [0] and [1]), and when the object is
destroyed, the pipe is closed (both ends).
gdb/ChangeLog:
yyyy-mm-dd Sergio Durigan Junior <sergiodj@redhat.com>
* unittests/scoped_pipe-selftests.c: New file.
gdbsupport/ChangeLog:
yyyy-mm-dd Sergio Durigan Junior <sergiodj@redhat.com>
* scoped_pipe.h: New file.
---
gdb/Makefile.in | 1 +
gdb/unittests/scoped_pipe-selftests.c | 96 +++++++++++++++++++++++++++
gdbsupport/scoped_pipe.h | 63 ++++++++++++++++++
3 files changed, 160 insertions(+)
create mode 100644 gdb/unittests/scoped_pipe-selftests.c
create mode 100644 gdbsupport/scoped_pipe.h
Comments
>>>>> "Sergio" == Sergio Durigan Junior <sergiodj@redhat.com> writes:
Sergio> gdb/ChangeLog:
Sergio> yyyy-mm-dd Sergio Durigan Junior <sergiodj@redhat.com>
Sergio> * unittests/scoped_pipe-selftests.c: New file.
Sergio> gdbsupport/ChangeLog:
Sergio> yyyy-mm-dd Sergio Durigan Junior <sergiodj@redhat.com>
Sergio> * scoped_pipe.h: New file.
I think new general-purpose code should go in gdbsupport.
Unfortunately right now we don't have a good way to put the unit tests
there. This is something we ought to do eventually though.
Sergio> +#ifndef COMMON_SCOPED_PIPE_H
I think we've been using GDBSUPPORT rather than COMMON now.
Sergio> + explicit scoped_pipe ()
I think explicit is only needed for 1-arg constructors.
Tom
On Friday, February 28 2020, Tom Tromey wrote:
>>>>>> "Sergio" == Sergio Durigan Junior <sergiodj@redhat.com> writes:
>
> Sergio> gdb/ChangeLog:
> Sergio> yyyy-mm-dd Sergio Durigan Junior <sergiodj@redhat.com>
>
> Sergio> * unittests/scoped_pipe-selftests.c: New file.
>
> Sergio> gdbsupport/ChangeLog:
> Sergio> yyyy-mm-dd Sergio Durigan Junior <sergiodj@redhat.com>
>
> Sergio> * scoped_pipe.h: New file.
>
> I think new general-purpose code should go in gdbsupport.
Yep. scoped_pipe.h is there.
> Unfortunately right now we don't have a good way to put the unit tests
> there. This is something we ought to do eventually though.
Right, that's something I noticed as well.
> Sergio> +#ifndef COMMON_SCOPED_PIPE_H
>
> I think we've been using GDBSUPPORT rather than COMMON now.
Ah, OK. I found other places using COMMON, but I'll change it here.
> Sergio> + explicit scoped_pipe ()
>
> I think explicit is only needed for 1-arg constructors.
OK, I'll remove the keyword.
I'll make the changes locally.
Thanks,
>> I think new general-purpose code should go in gdbsupport.
Sergio> Yep. scoped_pipe.h is there.
Lol, sorry about that.
Tom
On 2/26/20 8:05 PM, Sergio Durigan Junior wrote:
> --- /dev/null
> +++ b/gdb/unittests/scoped_pipe-selftests.c
> @@ -0,0 +1,96 @@
> +
> +#include "defs.h"
> +
> +#include "gdbsupport/scoped_pipe.h"
> +#include "config.h"
Was there a reason for this "config.h" include?
Pedro Alves
On Friday, February 28 2020, Pedro Alves wrote:
> On 2/26/20 8:05 PM, Sergio Durigan Junior wrote:
>
>> --- /dev/null
>> +++ b/gdb/unittests/scoped_pipe-selftests.c
>> @@ -0,0 +1,96 @@
>
>> +
>> +#include "defs.h"
>> +
>> +#include "gdbsupport/scoped_pipe.h"
>> +#include "config.h"
>
> Was there a reason for this "config.h" include?
I copied this test from the existing scoped_fd-selftests.c and adjusted
it. I did remove other includes, but left this one untouched. I tried
removing it now, and the file builds just fine, so I'll update my copy
of the patch here. Thanks!
On Friday, February 28 2020, Tom Tromey wrote:
>>> I think new general-purpose code should go in gdbsupport.
>
> Sergio> Yep. scoped_pipe.h is there.
>
> Lol, sorry about that.
That's alright! I was confused with your comment, but wasn't sure if
you meant something else by it ;-).
On 2/28/20 7:47 PM, Sergio Durigan Junior wrote:
> On Friday, February 28 2020, Pedro Alves wrote:
>
>> On 2/26/20 8:05 PM, Sergio Durigan Junior wrote:
>>
>>> --- /dev/null
>>> +++ b/gdb/unittests/scoped_pipe-selftests.c
>>> @@ -0,0 +1,96 @@
>>
>>> +
>>> +#include "defs.h"
>>> +
>>> +#include "gdbsupport/scoped_pipe.h"
>>> +#include "config.h"
>>
>> Was there a reason for this "config.h" include?
>
> I copied this test from the existing scoped_fd-selftests.c and adjusted
> it. I did remove other includes, but left this one untouched. I tried
> removing it now, and the file builds just fine, so I'll update my copy
> of the patch here. Thanks!
Ah, I see. That config.h include shouldn't be there in
scoped_fd-selftests.c either.
Thanks,
Pedro Alves
@@ -444,6 +444,7 @@ SUBDIR_UNITTESTS_SRCS = \
unittests/rsp-low-selftests.c \
unittests/scoped_fd-selftests.c \
unittests/scoped_mmap-selftests.c \
+ unittests/scoped_pipe-selftests.c \
unittests/scoped_restore-selftests.c \
unittests/string_view-selftests.c \
unittests/style-selftests.c \
new file mode 100644
@@ -0,0 +1,96 @@
+/* Self tests for scoped_pipe for GDB, the GNU debugger.
+
+ 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/>. */
+
+#include "defs.h"
+
+#include "gdbsupport/scoped_pipe.h"
+#include "config.h"
+#include "gdbsupport/selftest.h"
+
+namespace selftests {
+namespace scoped_pipe {
+
+/* Test that the pipe is correctly created. */
+
+static void
+test_create ()
+{
+ ::scoped_pipe spipe;
+
+ SELF_CHECK (spipe.get_read_end () > 0);
+ SELF_CHECK (spipe.get_write_end () > 0);
+}
+
+/* Test that we can write and read from the pipe. */
+
+static void
+test_transmission ()
+{
+ int foo = 123;
+ ::scoped_pipe spipe;
+
+ /* Write to the pipe. */
+ {
+ ssize_t writeret;
+
+ do
+ {
+ writeret = write (spipe.get_write_end (), &foo, sizeof (foo));
+ }
+ while (writeret < 0 && (errno == EAGAIN || errno == EINTR));
+
+ SELF_CHECK (writeret > 0);
+ }
+
+ /* Read from the pipe, and check if the value read is the same as
+ the one that was written. */
+ {
+ ssize_t readret;
+ int read_foo;
+
+ do
+ {
+ readret = read (spipe.get_read_end (), &read_foo, sizeof (read_foo));
+ }
+ while (readret < 0 && (errno == EAGAIN || errno == EINTR));
+
+ SELF_CHECK (readret > 0);
+
+ SELF_CHECK (read_foo == foo);
+ }
+}
+
+/* Run selftests. */
+static void
+run_tests ()
+{
+ test_create ();
+ test_transmission ();
+}
+
+} /* namespace scoped_pipe */
+} /* namespace selftests */
+
+void _initialize_scoped_pipe_selftests ();
+void
+_initialize_scoped_pipe_selftests ()
+{
+ selftests::register_test ("scoped_pipe",
+ selftests::scoped_pipe::run_tests);
+}
new file mode 100644
@@ -0,0 +1,63 @@
+/* scoped_pipe, automatically close a pipe.
+
+ 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 COMMON_SCOPED_PIPE_H
+#define COMMON_SCOPED_PIPE_H
+
+#include <unistd.h>
+#include "filestuff.h"
+
+/* A smart-pointer-like class to automatically close a pipe. */
+
+class scoped_pipe
+{
+public:
+ explicit scoped_pipe ()
+ {
+ if (gdb_pipe_cloexec (m_pipe) < 0)
+ error (_("gdb_pipe_cloexec: %s"), safe_strerror (errno));
+ }
+
+ ~scoped_pipe ()
+ {
+ if (m_pipe[0] >= 0)
+ close (m_pipe[0]);
+ if (m_pipe[1] >= 0)
+ close (m_pipe[1]);
+ }
+
+ DISABLE_COPY_AND_ASSIGN (scoped_pipe);
+
+ /* Get the read end of the pipe. */
+ int get_read_end () const noexcept
+ {
+ return m_pipe[0];
+ }
+
+ /* Get the write end of the pipe. */
+ int get_write_end () const noexcept
+ {
+ return m_pipe[1];
+ }
+
+private:
+ int m_pipe[2];
+};
+
+#endif /* ! COMMON_SCOPED_PIPE_H */