[Settings] Expose SMBIOS via settings API

In particular, expose the system UUID as a setting ("smbios/uuid").

src/arch/i386/firmware/pcbios/smbios_settings.c

@@ -0,0 +1,158 @@
+/*
+ * Copyright (C) 2008 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <stdint.h>
+#include <string.h>
+#include <errno.h>
+#include <gpxe/settings.h>
+#include <gpxe/init.h>
+#include <gpxe/uuid.h>
+#include <smbios.h>
+
+/**
+ * Construct SMBIOS raw-data tag
+ *
+ * @v _type		SMBIOS structure type number
+ * @v _structure	SMBIOS structure data type
+ * @v _field		Field within SMBIOS structure data type
+ * @ret tag		SMBIOS setting tag
+ */
+#define SMBIOS_RAW_TAG( _type, _structure, _field )		\
+	( ( (_type) << 16 ) |					\
+	  ( offsetof ( _structure, _field ) << 8 ) |		\
+	  ( sizeof ( ( ( _structure * ) 0 )->_field ) ) )
+
+/**
+ * Construct SMBIOS string tag
+ *
+ * @v _type		SMBIOS structure type number
+ * @v _structure	SMBIOS structure data type
+ * @v _field		Field within SMBIOS structure data type
+ * @ret tag		SMBIOS setting tag
+ */
+#define SMBIOS_STRING_TAG( _type, _structure, _field )		\
+	( ( (_type) << 16 ) |					\
+	  ( offsetof ( _structure, _field ) << 8 ) )
+
+/**
+ * Store value of SMBIOS setting
+ *
+ * @v settings		Settings block
+ * @v setting		Setting to store
+ * @v data		Setting data, or NULL to clear setting
+ * @v len		Length of setting data
+ * @ret rc		Return status code
+ */
+static int smbios_store ( struct settings *settings __unused,
+			  struct setting *setting __unused,
+			  const void *data __unused, size_t len __unused ) {
+	/* Cannot write data into SMBIOS */
+	return -ENOTSUP;
+}
+
+/**
+ * Fetch value of SMBIOS setting
+ *
+ * @v settings		Settings block, or NULL to search all blocks
+ * @v setting		Setting to fetch
+ * @v data		Buffer to fill with setting data
+ * @v len		Length of buffer
+ * @ret len		Length of setting data, or negative error
+ */
+static int smbios_fetch ( struct settings *settings __unused,
+			  struct setting *setting,
+			  void *data, size_t len ) {
+	struct smbios_structure structure;
+	unsigned int tag_type;
+	unsigned int tag_offset;
+	unsigned int tag_len;
+	int rc;
+
+	/* Split tag into type, offset and length */
+	tag_type = ( setting->tag >> 16 );
+	tag_offset = ( ( setting->tag >> 8 ) & 0xff );
+	tag_len = ( setting->tag & 0xff );
+	if ( ! tag_type )
+		return -ENOENT;
+
+	/* Find SMBIOS structure */
+	if ( ( rc = find_smbios_structure ( tag_type, &structure ) ) != 0 )
+		return rc;
+
+	{
+		uint8_t buf[structure.header.len];
+
+		/* Read SMBIOS structure */
+		if ( ( rc = read_smbios_structure ( &structure, buf,
+						    sizeof ( buf ) ) ) != 0 )
+			return rc;
+
+		if ( tag_len == 0 ) {
+			/* String */
+			return read_smbios_string ( &structure,
+						    buf[tag_offset],
+						    data, len );
+		} else {
+			/* Raw data */
+			if ( len > tag_len )
+				len = tag_len;
+			memcpy ( data, &buf[tag_offset], len );
+			return tag_len;
+		}
+	}
+}
+
+/** SMBIOS settings operations */
+static struct settings_operations smbios_settings_operations = {
+	.store = smbios_store,
+	.fetch = smbios_fetch,
+};
+
+/** SMBIOS settings */
+static struct settings smbios_settings = {
+	.refcnt = NULL,
+	.name = "smbios",
+	.siblings = LIST_HEAD_INIT ( smbios_settings.siblings ),
+	.children = LIST_HEAD_INIT ( smbios_settings.children ),
+	.op = &smbios_settings_operations,
+};
+
+/** Initialise SMBIOS settings */
+static void smbios_init ( void ) {
+	int rc;
+
+	if ( ( rc = register_settings ( &smbios_settings, NULL ) ) != 0 ) {
+		DBG ( "SMBIOS could not register settings: %s\n",
+		      strerror ( rc ) );
+		return;
+	}
+}
+
+/** SMBIOS settings initialiser */
+struct init_fn smbios_init_fn __init_fn ( INIT_NORMAL ) = {
+	.initialise = smbios_init,
+};
+
+/** UUID setting obtained via SMBIOS */
+struct setting uuid_setting __setting = {
+	.name = "uuid",
+	.description = "UUID",
+	.tag = SMBIOS_RAW_TAG ( SMBIOS_TYPE_SYSTEM_INFORMATION,
+				struct smbios_system_information, uuid ),
+	.type = &setting_type_uuid,
+};