Add the ability for GDB to printout the thread name along with other

thread specific informations.

In order to do that, and in order to avoid KBI breakage with existing
infrastructure the following semantic is implemented:
- For live programs, a new member to the PT_LWPINFO is added (pl_tdname)
- For cores, a new ELF note is added (NT_THRMISC) that can be used for
  storing thread specific, miscellaneous, informations. Right now it is
  just popluated with a thread name.

GDB, then, retrieves the correct informations from the corefile via the
BFD interface, as it groks the ELF notes and create appropriate
pseudo-sections.

Sponsored by:	Sandvine Incorporated
Tested by:	gianni
Discussed with:	dim, kan, kib
MFC after:	2 weeks

1 files changed, 44 insertions, 3 deletions

diff --git a/gnu/usr.bin/gdb/libgdb/fbsd-threads.c b/gnu/usr.bin/gdb/libgdb/fbsd-threads.c
index 51890eb..04a96b0 100644
--- a/gnu/usr.bin/gdb/libgdb/fbsd-threads.c
+++ b/gnu/usr.bin/gdb/libgdb/fbsd-threads.c
@@ -426,6 +426,46 @@ fbsd_thread_deactivate (void)
   init_thread_list ();
 }
 
+static char * 
+fbsd_thread_get_name (lwpid_t lwpid)
+{
+  static char last_thr_name[MAXCOMLEN + 1];
+  char section_name[32];
+  struct ptrace_lwpinfo lwpinfo;
+  bfd_size_type size;
+  struct bfd_section *section;
+
+  if (target_has_execution)
+    {
+      if (ptrace (PT_LWPINFO, lwpid, (caddr_t)&lwpinfo, sizeof (lwpinfo)) == -1)
+        goto fail;
+      strncpy (last_thr_name, lwpinfo.pl_tdname, sizeof (last_thr_name) - 1);
+    }
+  else
+    {
+      snprintf (section_name, sizeof (section_name), ".tname/%u", lwpid);
+      section = bfd_get_section_by_name (core_bfd, section_name);
+      if (! section)
+        goto fail;
+
+      /* Section size fix-up. */
+      size = bfd_section_size (core_bfd, section);
+      if (size > sizeof (last_thr_name))
+        size = sizeof (last_thr_name);
+
+      if (! bfd_get_section_contents (core_bfd, section, last_thr_name,
+	       (file_ptr)0, size))
+        goto fail;
+      if (last_thr_name[0] == '\0')
+        goto fail;
+    }
+    last_thr_name[sizeof (last_thr_name) - 1] = '\0';
+    return last_thr_name;
+fail:
+     strcpy (last_thr_name, "<unknown>");
+     return last_thr_name;
+}
+
 static void
 fbsd_thread_new_objfile (struct objfile *objfile)
 {
@@ -1158,7 +1198,7 @@ fbsd_thread_find_new_threads (void)
 static char *
 fbsd_thread_pid_to_str (ptid_t ptid)
 {
-  static char buf[64];
+  static char buf[64 + MAXCOMLEN];
 
   if (IS_THREAD (ptid))
     {
@@ -1178,8 +1218,9 @@ fbsd_thread_pid_to_str (ptid_t ptid)
 
       if (ti.ti_lid != 0)
         {
-          snprintf (buf, sizeof (buf), "Thread %llx (LWP %d)",
-                    (unsigned long long)th.th_thread, ti.ti_lid);
+          snprintf (buf, sizeof (buf), "Thread %llx (LWP %d/%s)",
+                    (unsigned long long)th.th_thread, ti.ti_lid,
+                    fbsd_thread_get_name (ti.ti_lid));
         }
       else
         {