[PATCH] Implement nbsd_nat_target::thread_alive

[Kamil Rytarowski <n54@gmx.com>]

gdb/ChangeLog:

	* nbsd-nat.h (nbsd_nat_target::thread_alive): Add.
	* nbsd-nat.c (nbsd_nat_target::thread_alive): Add.
---
 gdb/ChangeLog  |  5 +++++
 gdb/nbsd-nat.c | 30 ++++++++++++++++++++++++++++++
 gdb/nbsd-nat.h |  1 +
 3 files changed, 36 insertions(+)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 1ee58a541cb..d6789f4d7ca 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2020-03-25  Kamil Rytarowski  <n54@gmx.com>
+
+	* nbsd-nat.h (nbsd_nat_target::thread_alive): Add.
+	* nbsd-nat.c (nbsd_nat_target::thread_alive): Add.
+
 2020-03-25  Tom Tromey  <tom@tromey.com>

 	* compile/compile-object-load.c (get_out_value_type): Mention
diff --git a/gdb/nbsd-nat.c b/gdb/nbsd-nat.c
index 326bbe3aec3..aa0353309df 100644
--- a/gdb/nbsd-nat.c
+++ b/gdb/nbsd-nat.c
@@ -39,3 +39,33 @@ nbsd_nat_target::pid_to_exec_file (int pid)
     return NULL;
   return buf;
 }
+
+bool
+thread_alive (ptid_t ptid)
+{
+  pid_t pid = ptid.pid ();
+  int lwp = ptid.lwp ();
+  int mib[5] = {CTL_KERN, KERN_LWP, pid, sizeof (struct kinfo_lwp), 0};
+  size_t size;
+
+  if (sysctl (mib, 5, 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 (kl == NULL)
+    perror_with_name (("calloc"));
+
+  if (sysctl (mib, 5, kl.get (), &size, NULL, 0) == -1 || size == 0)
+    perror_with_name (("sysctl"));
+
+  for (size_t i = 0; i < size / sizeof (struct kinfo_lwp); i++)
+    {
+      if (kl.get ()[i].l_lid == lwp)
+	 return true;
+    }
+
+  return false;
+}
diff --git a/gdb/nbsd-nat.h b/gdb/nbsd-nat.h
index a752fbe572d..11b49427a44 100644
--- a/gdb/nbsd-nat.h
+++ b/gdb/nbsd-nat.h
@@ -27,6 +27,7 @@
 struct nbsd_nat_target : public inf_ptrace_target
 {
   char *pid_to_exec_file (int pid) override;
+  bool thread_alive (ptid_t ptid) override;
 };

 #endif /* nbsd-nat.h */
--
2.25.0