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Re: [PATCH/RFC] Support rthreads on OpenBSD 5.2 and later.
- From: Mark Kettenis <mark dot kettenis at xs4all dot nl>
- To: palves at redhat dot com
- Cc: gdb-patches at sourceware dot org
- Date: Fri, 28 Feb 2014 22:54:36 +0100 (CET)
- Subject: Re: [PATCH/RFC] Support rthreads on OpenBSD 5.2 and later.
- Authentication-results: sourceware.org; auth=none
- References: <201402272243 dot s1RMheVq007573 at glazunov dot sibelius dot xs4all dot nl> <53106C21 dot 9050608 at redhat dot com>
> Date: Fri, 28 Feb 2014 10:59:45 +0000
> From: Pedro Alves <palves@redhat.com>
>
> Hey Mark,
>
> On 02/27/2014 10:43 PM, Mark Kettenis wrote:
> > OpenBSD 5.2 and later has a proper threads implementation based on
> > kernel threads. Debugging support is provided through additional
> > ptrace(2) requests, so this diff extends the generic code in
> > inf-ptrace.c with OpenBSD-specific code to discover additional
> > threads.
>
> Cool.
>
> > I intend to commit this in a couple of days as I don't really expect
> > other people to care. But comments are welcome...
>
> :-)
>
> Looks fine to me. Comments below.
>
> > gdb/ChangeLog:
> >
> > * obsd-nat.h: New file.
> > * obsd-nat.c: New file.
>
> Don't forget to Makefile glue to actually build this. :-)
Thanks!
> > +
> > +static void
> > +obsd_find_new_threads (struct target_ops *ops)
> > +{
> > + pid_t pid = ptid_get_pid (inferior_ptid);
> > + struct ptrace_thread_state pts;
> > +
> > + if (ptrace(PT_GET_THREAD_FIRST, pid, (caddr_t)&pts, sizeof pts) == -1)
>
> "ptrace ("
>
> "(caddr_t) &pts"
Hmm, thye current codebase uses both styles, and inf-ptrace.c, where
most of this code cam from doesn't add the extra space. So I left it
alone for now But I'm probably responsible for that myself, and the
GNU coding standards do suggest the extra space. Want me to do a
sweep and fix them all?
Below is what I committed.
>From 863e4da4b6713fbd0b3a19fe3a7f7be1ea34f704 Mon Sep 17 00:00:00 2001
From: Mark Kettenis <kettenis@gnu.org>
Date: Thu, 27 Feb 2014 23:23:46 +0100
Subject: [PATCH] Support rthreads on OpenBSD 5.2 and later.
OpenBSD 5.2 and later have a proper threads implementation based on
kernel threads. Debugging support is provided through additional
ptrace(2) requests, so this diff extends the generic code in
inf-ptrace.c with OpenBSD-specific code to discover additional threads.
gdb/ChangeLog:
* obsd-nat.h: New file.
* obsd-nat.c: New file.
* Makefile.in (HFILES_NO_SRCDIR): Add obsd-nat.h.
(ALLDEPFILES): Add obsd-nat.c.
---
gdb/ChangeLog | 7 +++
gdb/Makefile.in | 4 +-
gdb/obsd-nat.c | 185 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
gdb/obsd-nat.h | 25 ++++++++
4 files changed, 219 insertions(+), 2 deletions(-)
create mode 100644 gdb/obsd-nat.c
create mode 100644 gdb/obsd-nat.h
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 2c615be..0633829 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,10 @@
+2014-02-28 Mark Kettenis <kettenis@gnu.org>
+
+ * obsd-nat.h: New file.
+ * obsd-nat.c: New file.
+ * Makefile.in (HFILES_NO_SRCDIR): Add obsd-nat.h.
+ (ALLDEPFILES): Add obsd-nat.c.
+
2014-02-28 Tom Tromey <tromey@redhat.com>
* cli-out.c (cli_ui_out_impl): Now const. Remove comment.
diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index fe06988..c8e2c9d 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -864,7 +864,7 @@ gnulib/import/string.in.h gnulib/import/str-two-way.h \
gnulib/import/stdint.in.h remote.h remote-notif.h gdb.h sparc-nat.h \
gdbthread.h dwarf2-frame.h dwarf2-frame-tailcall.h nbsd-nat.h dcache.h \
amd64-nat.h s390-linux-tdep.h arm-linux-tdep.h exceptions.h macroscope.h \
-gdbarch.h bsd-uthread.h memory-map.h memrange.h \
+gdbarch.h bsd-uthread.h memory-map.h memrange.h obsd-nat.h \
mdebugread.h m88k-tdep.h stabsread.h hppa-linux-offsets.h linux-fork.h \
ser-unix.h inf-ptrace.h terminal.h ui-out.h frame-base.h \
f-lang.h dwarf2loc.h value.h sparc-tdep.h defs.h target-descriptions.h \
@@ -1639,7 +1639,7 @@ ALLDEPFILES = \
mips64obsd-nat.c mips64obsd-tdep.c \
msp430-tdep.c \
nios2-tdep.c nios2-linux-tdep.c \
- nbsd-nat.c nbsd-tdep.c obsd-tdep.c \
+ nbsd-nat.c nbsd-tdep.c obsd-nat.c obsd-tdep.c \
solib-osf.c \
somread.c solib-som.c \
posix-hdep.c \
diff --git a/gdb/obsd-nat.c b/gdb/obsd-nat.c
new file mode 100644
index 0000000..c17a565
--- /dev/null
+++ b/gdb/obsd-nat.c
@@ -0,0 +1,185 @@
+/* Native-dependent code for OpenBSD.
+
+ Copyright (C) 2012-2014 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 "gdbthread.h"
+#include "inferior.h"
+#include "target.h"
+
+#include "gdb_assert.h"
+#include <sys/types.h>
+#include <sys/ptrace.h>
+#include <sys/wait.h>
+
+#include "inf-child.h"
+#include "obsd-nat.h"
+
+/* OpenBSD 5.2 and later include rthreads which uses a thread model
+ that maps userlan threads directly onto kernel threads in a 1:1
+ fashion. */
+
+#ifdef PT_GET_THREAD_FIRST
+
+static char *
+obsd_pid_to_str (struct target_ops *ops, ptid_t ptid)
+{
+ if (ptid_get_lwp (ptid) != 0)
+ {
+ static char buf[64];
+
+ xsnprintf (buf, sizeof buf, "thread %ld", ptid_get_lwp (ptid));
+ return buf;
+ }
+
+ return normal_pid_to_str (ptid);
+}
+
+static void
+obsd_find_new_threads (struct target_ops *ops)
+{
+ pid_t pid = ptid_get_pid (inferior_ptid);
+ struct ptrace_thread_state pts;
+
+ if (ptrace(PT_GET_THREAD_FIRST, pid, (caddr_t)&pts, sizeof pts) == -1)
+ perror_with_name (("ptrace"));
+
+ while (pts.pts_tid != -1)
+ {
+ ptid_t ptid = ptid_build (pid, pts.pts_tid, 0);
+
+ if (!in_thread_list (ptid))
+ {
+ if (ptid_get_lwp (inferior_ptid) == 0)
+ thread_change_ptid (inferior_ptid, ptid);
+ else
+ add_thread (ptid);
+ }
+
+ if (ptrace(PT_GET_THREAD_NEXT, pid, (caddr_t)&pts, sizeof pts) == -1)
+ perror_with_name (("ptrace"));
+ }
+}
+
+static ptid_t
+obsd_wait (struct target_ops *ops,
+ ptid_t ptid, struct target_waitstatus *ourstatus, int options)
+{
+ pid_t pid;
+ int status, save_errno;
+
+ do
+ {
+ set_sigint_trap ();
+
+ do
+ {
+ pid = waitpid (ptid_get_pid (ptid), &status, 0);
+ save_errno = errno;
+ }
+ while (pid == -1 && errno == EINTR);
+
+ clear_sigint_trap ();
+
+ if (pid == -1)
+ {
+ fprintf_unfiltered (gdb_stderr,
+ _("Child process unexpectedly missing: %s.\n"),
+ safe_strerror (save_errno));
+
+ /* Claim it exited with unknown signal. */
+ ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
+ ourstatus->value.sig = GDB_SIGNAL_UNKNOWN;
+ return inferior_ptid;
+ }
+
+ /* Ignore terminated detached child processes. */
+ if (!WIFSTOPPED (status) && pid != ptid_get_pid (inferior_ptid))
+ pid = -1;
+ }
+ while (pid == -1);
+
+ ptid = pid_to_ptid (pid);
+
+ if (WIFSTOPPED (status))
+ {
+ ptrace_state_t pe;
+ pid_t fpid;
+
+ if (ptrace (PT_GET_PROCESS_STATE, pid, (caddr_t)&pe, sizeof pe) == -1)
+ perror_with_name (("ptrace"));
+
+ switch (pe.pe_report_event)
+ {
+ case PTRACE_FORK:
+ ourstatus->kind = TARGET_WAITKIND_FORKED;
+ ourstatus->value.related_pid = pid_to_ptid (pe.pe_other_pid);
+
+ /* Make sure the other end of the fork is stopped too. */
+ fpid = waitpid (pe.pe_other_pid, &status, 0);
+ if (fpid == -1)
+ perror_with_name (("waitpid"));
+
+ if (ptrace (PT_GET_PROCESS_STATE, fpid,
+ (caddr_t)&pe, sizeof pe) == -1)
+ perror_with_name (("ptrace"));
+
+ gdb_assert (pe.pe_report_event == PTRACE_FORK);
+ gdb_assert (pe.pe_other_pid == pid);
+ if (fpid == ptid_get_pid (inferior_ptid))
+ {
+ ourstatus->value.related_pid = pid_to_ptid (pe.pe_other_pid);
+ return pid_to_ptid (fpid);
+ }
+
+ return pid_to_ptid (pid);
+ }
+
+ ptid = ptid_build (pid, pe.pe_tid, 0);
+ if (!in_thread_list (ptid))
+ {
+ if (ptid_get_lwp (inferior_ptid) == 0)
+ thread_change_ptid (inferior_ptid, ptid);
+ else
+ add_thread (ptid);
+ }
+ }
+
+ store_waitstatus (ourstatus, status);
+ return ptid;
+}
+
+void
+obsd_add_target (struct target_ops *t)
+{
+ /* Override some methods to support threads. */
+ t->to_pid_to_str = obsd_pid_to_str;
+ t->to_find_new_threads = obsd_find_new_threads;
+ t->to_wait = obsd_wait;
+ add_target (t);
+}
+
+#else
+
+void
+obsd_add_target (struct target_ops *t)
+{
+ add_target (t);
+}
+
+#endif /* PT_GET_THREAD_FIRST */
diff --git a/gdb/obsd-nat.h b/gdb/obsd-nat.h
new file mode 100644
index 0000000..ad021fc
--- /dev/null
+++ b/gdb/obsd-nat.h
@@ -0,0 +1,25 @@
+/* Native-dependent code for OpenBSD.
+
+ Copyright (C) 2014 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 OBSD_NAT_H
+#define OBSD_NAT_H
+
+extern void obsd_add_target (struct target_ops *);
+
+#endif /* obsd-nat.h */
--
1.8.5.3