[PATCH v2 05/10] Add gdb/nat common functions for listing threads

Kamil Rytarowski
2020-09-04T00:30:05Z

Add netbsd_nat::netbsd_thread_lister a generic thread lister, used
internally in netbsd-nat.c, copied from gdb/nbsd-nat.c.

Add public extern functions for listing threads:
* netbsd_nat::thread_alive
* netbsd_nat::thread_name
* netbsd_nat::for_each_thread

gdb/ChangeLog:

* netbsd-nat.h: Include "gdbsupport/function-view.h".
* (netbsd_nat::thread_alive, netbsd_nat::thread_name)
(netbsd_nat::for_each_thread): Add.
* netbsd-nat.c: Include "gdbsupport/common-defs.h" and
"gdbsupport/common-debug.h".
* (netbsd_nat::netbsd_thread_lister)
(netbsd_nat::thread_alive, netbsd_nat::thread_name)
(netbsd_nat::for_each_thread): Add.
---
gdb/ChangeLog | 11 ++++
gdb/nat/netbsd-nat.c | 123 +++++++++++++++++++++++++++++++++++++++++++
gdb/nat/netbsd-nat.h | 8 +++
3 files changed, 142 insertions(+)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 335d6b7271f..b9b028ebe68 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,14 @@
+2020-09-04 Kamil Rytarowski <n54@gmx.com>
+
+ * netbsd-nat.h: Include "gdbsupport/function-view.h".
+ * (netbsd_nat::thread_alive, netbsd_nat::thread_name)
+ (netbsd_nat::for_each_thread): Add.
+ * netbsd-nat.c: Include "gdbsupport/common-defs.h" and
+ "gdbsupport/common-debug.h".
+ * (netbsd_nat::netbsd_thread_lister)
+ (netbsd_nat::thread_alive, netbsd_nat::thread_name)
+ (netbsd_nat::for_each_thread): Add.
+
2020-09-04 Kamil Rytarowski <n54@gmx.com>

* netbsd-nat.h: Include <unistd.h>.
diff --git a/gdb/nat/netbsd-nat.c b/gdb/nat/netbsd-nat.c
index 297188bb8b4..bd28e116b56 100644
--- a/gdb/nat/netbsd-nat.c
+++ b/gdb/nat/netbsd-nat.c
@@ -17,11 +17,17 @@
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 "gdbsupport/common-defs.h"
#include "nat/netbsd-nat.h"
+#include "gdbsupport/common-debug.h"

#include <sys/types.h>
#include <sys/sysctl.h>

+#include <cstring>
+
+#include "gdbsupport/function-view.h"
+
namespace netbsd_nat
{

@@ -39,4 +45,121 @@ pid_to_exec_file (pid_t pid)
return buf;
}

+/* Generic thread (LWP) lister within a specified process. The callback
+ parameters is a C++ function that is called for each detected thread. */
+
+static bool
+netbsd_thread_lister (const pid_t pid,
+ gdb::function_view<bool (const struct kinfo_lwp *)>
+ callback)
+{
+ int mib[5] = {CTL_KERN, KERN_LWP, pid, sizeof (struct kinfo_lwp), 0};
+ size_t size;
+
+ if (sysctl (mib, ARRAY_SIZE (mib), NULL, &size, NULL, 0) == -1 || size == 0)
+ perror_with_name (("sysctl"));
+
+ mib[4] = size / sizeof (size_t);
+
+ gdb::unique_xmalloc_ptr<struct kinfo_lwp[]> kl
+ ((struct kinfo_lwp *) xcalloc (size, 1));
+
+ if (sysctl (mib, ARRAY_SIZE (mib), kl.get (), &size, NULL, 0) == -1
+ || size == 0)
+ perror_with_name (("sysctl"));
+
+ for (size_t i = 0; i < size / sizeof (struct kinfo_lwp); i++)
+ {
+ struct kinfo_lwp *l = &kl[i];
+
+ /* Return true if the specified thread is alive. */
+ auto lwp_alive
+ = [] (struct kinfo_lwp *lwp)
+ {
+ switch (lwp->l_stat)
+ {
+ case LSSLEEP:
+ case LSRUN:
+ case LSONPROC:
+ case LSSTOP:
+ case LSSUSPENDED:
+ return true;
+ default:
+ return false;
+ }
+ };
+
+ /* Ignore embryonic or demised threads. */
+ if (!lwp_alive (l))
+ continue;
+
+ if (callback (l))
+ return true;
+ }
+
+ return false;
+}
+
+/* Return true if PTID is still active in the inferior. */
+
+bool
+thread_alive (ptid_t ptid)
+{
+ pid_t pid = ptid.pid ();
+ lwpid_t lwp = ptid.lwp ();
+
+ auto fn
+ = [&lwp] (const struct kinfo_lwp *kl)
+ {
+ return kl->l_lid == lwp;
+ };
+
+ return netbsd_thread_lister (pid, fn);
+}
+
+/* Return the name assigned to a thread by an application. Returns
+ the string in a static buffer. */
+
+const char *
+thread_name (ptid_t ptid)
+{
+ pid_t pid = ptid.pid ();
+ lwpid_t lwp = ptid.lwp ();
+
+ static char buf[KI_LNAMELEN] = {};
+
+ auto fn
+ = [&lwp] (const struct kinfo_lwp *kl)
+ {
+ if (kl->l_lid == lwp)
+ {
+ xsnprintf (buf, sizeof buf, "%s", kl->l_name);
+ return true;
+ }
+ return false;
+ };
+
+ if (netbsd_thread_lister (pid, fn))
+ return buf;
+ else
+ return NULL;
+}
+
+/* A generic thread lister within a specific PID. The CALLBACK parameter
+ is a C++ function that is called for each detected thread. */
+
+void
+for_each_thread (pid_t pid, gdb::function_view<void (ptid_t)> callback)
+{
+ auto fn
+ = [&callback, &pid] (const struct kinfo_lwp *kl)
+ {
+ ptid_t ptid = ptid_t (pid, kl->l_lid, 0);
+ callback (ptid);
+ return false;
+ };
+
+ netbsd_thread_lister (pid, fn);
+}
+
}
diff --git a/gdb/nat/netbsd-nat.h b/gdb/nat/netbsd-nat.h
index a5f664d95f4..c3a58ae7f49 100644
--- a/gdb/nat/netbsd-nat.h
+++ b/gdb/nat/netbsd-nat.h
@@ -20,6 +20,8 @@
#ifndef NAT_NETBSD_NAT_H
#define NAT_NETBSD_NAT_H

+#include "gdbsupport/function-view.h"
+
#include <unistd.h>

namespace netbsd_nat
@@ -27,6 +29,12 @@ namespace netbsd_nat

extern char *pid_to_exec_file (pid_t pid);

+extern bool thread_alive (ptid_t ptid);
+
+extern const char *thread_name (ptid_t ptid);
+
+extern void for_each_thread (pid_t pid,
+ gdb::function_view<void (ptid_t)> callback);
}

#endif
--
2.28.0