XML feature description support.

	* NEWS: Mention target descriptions, "set tdesc filename",
	"unset tdesc filename", "show tdesc filename", and
	qXfer:features:read.
	* arch-utils.c (choose_architecture_for_target): New function.
	(gdbarch_info_fill): Call it.
	* target-descriptions.c (struct property): Make members non-const.
	(struct target_desc): Add arch member.
	(target_description_filename): New variable.
	(target_find_description): Try via XML first.
	(tdesc_architecture): New.
	(free_target_description, make_cleanup_free_target_description): New.
	(set_tdesc_property): Call xstrdup.
	(set_tdesc_architecture, tdesc_set_cmdlist, tdesc_show_cmdlist)
	(tdesc_unset_cmdlist, unset_tdesc_cmd, unset_tdesc_filename_cmd)
	(set_tdesc_cmd, show_tdesc_cmd, set_tdesc_filename_cmd)
	(show_tdesc_filename_cmd, _initialize_target_descriptions): New.
	* target-descriptions.h (tdesc_architecture)
	(make_cleanup_free_target_description, set_tdesc_architecture): New
	prototypes.
	* Makefile.in (SFILES): Add xml-tdesc.c.
	(COMMON_OBS): Add xml-tdesc.o.
	(target-descriptions.o): Update.
	(xml-tdesc.o): New rule.
	* xml-tdesc.c, xml-tdesc.h: New files.
	* remote.c (PACKET_qXfer_features): New enum.
	(remote_protocol_features): Add qXfer:features:read.
	(remote_xfer_partial): Handle TARGET_OBJECT_AVAILABLE_FEATURES.
	(_initialize_remote): Register qXfer:features:read.
	* target.h (enum target_object): Add TARGET_OBJECT_AVAILABLE_FEATURES.
	* features/gdb-target.dtd: New file.

	* linux-i386-low.c (the_low_target): Set arch_string.
	* linux-x86-64-low.c (the_low_target): Likewise.
	* linux-low.c (linux_arch_string): New.
	(linux_target_ops): Add it.
	* linux-low.h (struct linux_target_ops): Add arch_string.
	* server.c (write_qxfer_response): Use const void * for DATA.
	(get_features_xml): New.
	(handle_query): Handle qXfer:features:read.  Report it for qSupported.
	* target.h (struct target_ops): Add arch_string method.

	* gdb.texinfo (Target Descriptions): New section.
	(General Query Packets): Add QPassSignals anchor.  Mention
	qXfer:features:read under qSupported.  Expand mentions of
	qXfer:memory-map:read and QPassSignals.  Document
	qXfer:features:read.

1 files changed, 68 insertions, 1 deletions

diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c
index 1f78cce..20d47c9 100644
--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -145,7 +145,7 @@ decode_xfer_read (char *buf, char **annex, CORE_ADDR *ofs, unsigned int *len)
    to as much of DATA/LEN as we could fit.  IS_MORE controls
    the first character of the response.  */
 static int
-write_qxfer_response (char *buf, unsigned char *data, int len, int is_more)
+write_qxfer_response (char *buf, const void *data, int len, int is_more)
 {
   int out_len;
 
@@ -192,6 +192,31 @@ handle_general_set (char *own_buf)
   own_buf[0] = 0;
 }
 
+static const char *
+get_features_xml (void)
+{
+  static int features_supported = -1;
+  static char *document;
+
+  if (features_supported == -1)
+    {
+      const char *arch = (*the_target->arch_string) ();
+
+      if (arch == NULL)
+	features_supported = 0;
+      else
+	{
+	  features_supported = 1;
+	  document = malloc (64 + strlen (arch));
+	  snprintf (document, 64 + strlen (arch),
+		    "<target><architecture>%s</architecture></target>",
+		    arch);
+	}
+    }
+
+  return document;
+}
+
 /* Handle all of the extended 'q' packets.  */
 void
 handle_query (char *own_buf, int *new_packet_len_p)
@@ -279,6 +304,45 @@ handle_query (char *own_buf, int *new_packet_len_p)
       return;
     }
 
+  if (strncmp ("qXfer:features:read:", own_buf, 20) == 0)
+    {
+      CORE_ADDR ofs;
+      unsigned int len, total_len;
+      const char *document;
+      char *annex;
+
+      document = get_features_xml ();
+      if (document == NULL)
+	{
+	  own_buf[0] = '\0';
+	  return;
+	}
+
+      /* Reject any annex other than target.xml; grab the offset and
+	 length.  */
+      if (decode_xfer_read (own_buf + 20, &annex, &ofs, &len) < 0
+	  || strcmp (annex, "target.xml") != 0)
+	{
+	  strcpy (own_buf, "E00");
+	  return;
+	}
+
+      total_len = strlen (document);
+      if (len > PBUFSIZ - 2)
+	len = PBUFSIZ - 2;
+
+      if (ofs > total_len)
+	write_enn (own_buf);
+      else if (len < total_len - ofs)
+	*new_packet_len_p = write_qxfer_response (own_buf, document + ofs,
+						  len, 1);
+      else
+	*new_packet_len_p = write_qxfer_response (own_buf, document + ofs,
+						  total_len - ofs, 0);
+
+      return;
+    }
+
   /* Protocol features query.  */
   if (strncmp ("qSupported", own_buf, 10) == 0
       && (own_buf[10] == ':' || own_buf[10] == '\0'))
@@ -288,6 +352,9 @@ handle_query (char *own_buf, int *new_packet_len_p)
       if (the_target->read_auxv != NULL)
 	strcat (own_buf, ";qXfer:auxv:read+");
 
+      if (get_features_xml () != NULL)
+	strcat (own_buf, ";qXfer:features:read+");
+
       return;
     }