Generate NT_PROCSTAT_{AUXV,VMMAP,PS_STRINGS} in FreeBSD coredumps

gcore generates NT_AUXV and NT_FILE notes for Linux targets.  On
FreeBSD auxv is stored in a NT_PROCSTAT_AUXV section, virtual memory
mappings are stored in a NT_PROCSTAT_VMMAP, and both are prefixed with
the struct size.  In addition, store a NT_PROCSTAT_PS_STRINGS note
saving the initial location of the argv[] and environment[] arrays.

gdb/ChangeLog:

	PR gdb/23105
	* fbsd-nat.c (fbsd_nat_target::xfer_partial): Add support for
	TARGET_OBJECT_FREEBSD_VMMAP and TARGET_OBJECT_FREEBSD_PS_STRINGS.
	* fbsd-tdep.c (fbsd_make_note_desc): New.
	(fbsd_make_corefile_notes): Write NT_PROCSTAT_AUXV,
	NT_PROCSTAT_VMMAP and NT_PROCSTAT_PS_STRINGS notes.
	* target.h (enum target_object) Add FreeBSD-specific
	TARGET_OBJECT_FREEBSD_VMMAP and TARGET_OBJECT_FREEBSD_PS_STRINGS.

1 files changed, 56 insertions, 0 deletions

diff --git a/gdb/fbsd-tdep.c b/gdb/fbsd-tdep.c
index 78d0c3d..ed43087 100644
--- a/gdb/fbsd-tdep.c
+++ b/gdb/fbsd-tdep.c
@@ -512,6 +512,28 @@ fbsd_corefile_thread (struct thread_info *info,
      args->note_size, args->stop_signal);
 }
 
+/* Return a byte_vector containing the contents of a core dump note
+   for the target object of type OBJECT.  If STRUCTSIZE is non-zero,
+   the data is prefixed with a 32-bit integer size to match the format
+   used in FreeBSD NT_PROCSTAT_* notes.  */
+
+static gdb::optional<gdb::byte_vector>
+fbsd_make_note_desc (enum target_object object, uint32_t structsize)
+{
+  gdb::optional<gdb::byte_vector> buf =
+    target_read_alloc (current_top_target (), object, NULL);
+  if (!buf || buf->empty ())
+    return {};
+
+  if (structsize == 0)
+    return buf;
+
+  gdb::byte_vector desc (sizeof (structsize) + buf->size ());
+  memcpy (desc.data (), &structsize, sizeof (structsize));
+  memcpy (desc.data () + sizeof (structsize), buf->data (), buf->size ());
+  return desc;
+}
+
 /* Create appropriate note sections for a corefile, returning them in
    allocated memory.  */
 
@@ -586,6 +608,40 @@ fbsd_make_corefile_notes (struct gdbarch *gdbarch, bfd *obfd, int *note_size)
 
   note_data = thread_args.note_data;
 
+  /* Auxiliary vector.  */
+  uint32_t structsize = gdbarch_ptr_bit (gdbarch) / 4; /* Elf_Auxinfo  */
+  gdb::optional<gdb::byte_vector> note_desc =
+    fbsd_make_note_desc (TARGET_OBJECT_AUXV, structsize);
+  if (note_desc && !note_desc->empty ())
+    {
+      note_data = elfcore_write_note (obfd, note_data, note_size, "FreeBSD",
+				      NT_FREEBSD_PROCSTAT_AUXV,
+				      note_desc->data (), note_desc->size ());
+      if (!note_data)
+	return NULL;
+    }
+
+  /* Virtual memory mappings.  */
+  note_desc = fbsd_make_note_desc (TARGET_OBJECT_FREEBSD_VMMAP, 0);
+  if (note_desc && !note_desc->empty ())
+    {
+      note_data = elfcore_write_note (obfd, note_data, note_size, "FreeBSD",
+				      NT_FREEBSD_PROCSTAT_VMMAP,
+				      note_desc->data (), note_desc->size ());
+      if (!note_data)
+	return NULL;
+    }
+
+  note_desc = fbsd_make_note_desc (TARGET_OBJECT_FREEBSD_PS_STRINGS, 0);
+  if (note_desc && !note_desc->empty ())
+    {
+      note_data = elfcore_write_note (obfd, note_data, note_size, "FreeBSD",
+				      NT_FREEBSD_PROCSTAT_PSSTRINGS,
+				      note_desc->data (), note_desc->size ());
+      if (!note_data)
+	return NULL;
+    }
+
   return note_data;
 }