[autoboot] Connect SAN disk during a filename boot, if applicable

For performing installations direct to a SAN target, it can be very
useful to hook a SAN disk and then proceed to perform a filename boot.
For example, the user may wish to hook the (empty) SAN installation
disk and then boot into the OS installer via TFTP.  This provides an
alternative mechanism to using "keep-san" and relying on the BIOS to
fall through to boot from the installation media, which is unreliable
on many BIOSes.

When a root-path is specified in addition to a boot filename, attempt
to hook the root-path as a SAN disk before booting from the specified
filename.  Since the root-path may be used for non-SAN purposes
(e.g. an NFS root mount point), ignore the root-path if it contains a
URI scheme that we do not support.

Originally-implemented-by: Jarrod Johnson <jarrod.b.johnson@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 185 insertions, 130 deletions

diff --git a/src/usr/autoboot.c b/src/usr/autoboot.c
index df152e3a..e7d6787a 100644
--- a/src/usr/autoboot.c
+++ b/src/usr/autoboot.c
@@ -27,6 +27,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <ipxe/image.h>
 #include <ipxe/sanboot.h>
 #include <ipxe/uri.h>
+#include <ipxe/open.h>
 #include <ipxe/init.h>
 #include <usr/ifmgmt.h>
 #include <usr/route.h>
@@ -57,30 +58,21 @@ static struct net_device * find_boot_netdev ( void ) {
 }
 
 /**
- * Boot using next-server and filename
+ * Parse next-server and filename into a URI
  *
- * @v filename		Boot filename
- * @ret rc		Return status code
+ * @v next_server	Next-server address
+ * @v filename		Filename
+ * @ret uri		URI, or NULL on failure
  */
-int boot_next_server_and_filename ( struct in_addr next_server,
-				    const char *filename ) {
+static struct uri * parse_next_server_and_filename ( struct in_addr next_server,
+						     const char *filename ) {
 	struct uri *uri;
-	struct image *image;
-	char buf[ 23 /* tftp://xxx.xxx.xxx.xxx/ */ +
-		  ( 3 * strlen(filename) ) /* completely URI-encoded */
-		  + 1 /* NUL */ ];
-	int filename_is_absolute;
-	int rc;
+	struct uri *tmp;
 
-	/* Construct URI */
+	/* Parse filename */
 	uri = parse_uri ( filename );
-	if ( ! uri ) {
-		printf ( "Could not parse \"%s\"\n", filename );
-		rc = -ENOMEM;
-		goto err_parse_uri;
-	}
-	filename_is_absolute = uri_is_absolute ( uri );
-	uri_put ( uri );
+	if ( ! uri )
+		return NULL;
 
 	/* Construct a tftp:// URI for the filename, if applicable.
 	 * We can't just rely on the current working URI, because the
@@ -88,41 +80,17 @@ int boot_next_server_and_filename ( struct in_addr next_server,
 	 * filenames with and without initial slashes, which is
 	 * significant for TFTP.
 	 */
-	if ( ! filename_is_absolute ) {
-		snprintf ( buf, sizeof ( buf ), "tftp://%s/",
-			   inet_ntoa ( next_server ) );
-		uri_encode ( filename, buf + strlen ( buf ),
-			     sizeof ( buf ) - strlen ( buf ), URI_PATH );
-		filename = buf;
+	if ( ! uri_is_absolute ( uri ) ) {
+		tmp = uri;
+		tmp->scheme = "tftp";
+		tmp->host = inet_ntoa ( next_server );
+		uri = uri_dup ( tmp );
+		uri_put ( tmp );
+		if ( ! uri )
+			return NULL;
 	}
 
-	/* Download and boot image */
-	image = alloc_image();
-	if ( ! image ) {
-		printf ( "Could not allocate image\n" );
-		rc = -ENOMEM;
-		goto err_alloc_image;
-	}
-	if ( ( rc = imgfetch ( image, filename,
-			       register_and_autoload_image ) ) != 0 ) {
-		printf ( "Could not fetch image: %s\n", strerror ( rc ) );
-		goto err_imgfetch;
-	}
-	if ( ( rc = imgexec ( image ) ) != 0 ) {
-		printf ( "Could not execute image: %s\n", strerror ( rc ) );
-		goto err_imgexec;
-	}
-
-	/* Drop image reference */
-	image_put ( image );
-	return 0;
-
- err_imgexec:
- err_imgfetch:
-	image_put ( image );
- err_alloc_image:
- err_parse_uri:
-	return rc;
+	return uri;
 }
 
 /** The "keep-san" setting */
@@ -142,71 +110,99 @@ struct setting skip_san_boot_setting __setting = {
 };
 
 /**
- * Boot using root path
+ * Boot from filename and root-path URIs
  *
+ * @v filename		Filename
  * @v root_path		Root path
  * @ret rc		Return status code
  */
-int boot_root_path ( const char *root_path ) {
-	struct uri *uri;
+int uriboot ( struct uri *filename, struct uri *root_path ) {
+	struct image *image;
 	int drive;
 	int rc;
 
-	/* Parse URI */
-	uri = parse_uri ( root_path );
-	if ( ! uri ) {
-		printf ( "Could not parse \"%s\"\n", root_path );
+	/* Allocate image */
+	image = alloc_image();
+	if ( ! image ) {
+		printf ( "Could not allocate image\n" );
 		rc = -ENOMEM;
-		goto err_parse_uri;
+		goto err_alloc_image;
+	}
+
+	/* Treat empty URIs as absent */
+	if ( filename && ( ! filename->path ) )
+		filename = NULL;
+	if ( root_path && ( ! uri_is_absolute ( root_path ) ) )
+		root_path = NULL;
+
+	/* If we have both a filename and a root path, ignore an
+	 * unsupported URI scheme in the root path, since it may
+	 * represent an NFS root.
+	 */
+	if ( filename && root_path &&
+	     ( xfer_uri_opener ( root_path->scheme ) == NULL ) ) {
+		printf ( "Ignoring unsupported root path\n" );
+		root_path = NULL;
 	}
 
-	/* Hook SAN device */
-	if ( ( drive = san_hook ( uri, 0 ) ) < 0 ) {
-		rc = drive;
-		printf ( "Could not open SAN device: %s\n",
-			 strerror ( rc ) );
-		goto err_open;
+	/* Hook SAN device, if applicable */
+	if ( root_path ) {
+		drive = san_hook ( root_path, 0 );
+		if ( drive < 0 ) {
+			rc = drive;
+			printf ( "Could not open SAN device: %s\n",
+				 strerror ( rc ) );
+			goto err_san_hook;
+		}
+		printf ( "Registered as SAN device %#02x\n", drive );
+	} else {
+		drive = -ENODEV;
 	}
-	printf ( "Registered as SAN device %#02x\n", drive );
 
-	/* Describe SAN device */
-	if ( ( rc = san_describe ( drive ) ) != 0 ) {
+	/* Describe SAN device, if applicable */
+	if ( ( drive >= 0 ) && ( ( rc = san_describe ( drive ) ) != 0 ) ) {
 		printf ( "Could not describe SAN device %#02x: %s\n",
 			 drive, strerror ( rc ) );
-		goto err_describe;
+		goto err_san_describe;
 	}
 
-	/* Boot from SAN device */
-	if ( fetch_intz_setting ( NULL, &skip_san_boot_setting) != 0 ) {
-		printf ( "Skipping boot from SAN device %#02x\n", drive );
+	/* Attempt filename or SAN boot as applicable */
+	if ( filename ) {
+		if ( ( rc = imgdownload ( image, filename,
+					  register_and_autoexec_image ) ) !=0){
+			printf ( "Could not chain image: %s\n",
+				 strerror ( rc ) );
+		}
+	} else if ( root_path ) {
+		if ( fetch_intz_setting ( NULL, &skip_san_boot_setting) == 0 ) {
+			printf ( "Booting from SAN device %#02x\n", drive );
+			rc = san_boot ( drive );
+			printf ( "Boot from SAN device %#02x failed: %s\n",
+				 drive, strerror ( rc ) );
+		} else {
+			printf ( "Skipping boot from SAN device %#02x\n",
+				 drive );
+			rc = 0;
+		}
 	} else {
-		printf ( "Booting from SAN device %#02x\n", drive );
-		rc = san_boot ( drive );
-		printf ( "Boot from SAN device %#02x failed: %s\n",
-			 drive, strerror ( rc ) );
+		printf ( "No filename or root path specified\n" );
+		rc = -ENOENT;
 	}
 
-	/* Leave drive registered, if instructed to do so */
-	if ( fetch_intz_setting ( NULL, &keep_san_setting ) != 0 ) {
-		printf ( "Preserving connection to SAN device %#02x\n",
-			 drive );
-		goto err_keep_san;
+ err_san_describe:
+	/* Unhook SAN device, if applicable */
+	if ( drive >= 0 ) {
+		if ( fetch_intz_setting ( NULL, &keep_san_setting ) == 0 ) {
+			printf ( "Unregistering SAN device %#02x\n", drive );
+			san_unhook ( drive );
+		} else {
+			printf ( "Preserving connection to SAN device %#02x\n",
+				 drive );
+		}
 	}
-
-	/* Unhook SAN deivce */
-	printf ( "Unregistering SAN device %#02x\n", drive );
-	san_unhook ( drive );
-
-	/* Drop URI reference */
-	uri_put ( uri );
-
-	return 0;
-
- err_keep_san:
- err_describe:
- err_open:
-	uri_put ( uri );
- err_parse_uri:
+ err_san_hook:
+	image_put ( image );
+ err_alloc_image:
 	return rc;
 }
 
@@ -227,12 +223,53 @@ static void close_all_netdevs ( void ) {
 }
 
 /**
- * Boot from a network device
+ * Fetch next-server and filename settings into a URI
  *
- * @v netdev		Network device
- * @ret rc		Return status code
+ * @v settings		Settings block
+ * @ret uri		URI, or NULL on failure
  */
-int netboot ( struct net_device *netdev ) {
+struct uri * fetch_next_server_and_filename ( struct settings *settings ) {
+	struct in_addr next_server;
+	char filename[256];
+
+	/* Fetch next-server setting */
+	fetch_ipv4_setting ( settings, &next_server_setting, &next_server );
+	if ( next_server.s_addr )
+		printf ( "Next server: %s\n", inet_ntoa ( next_server ) );
+
+	/* Fetch filename setting */
+	fetch_string_setting ( settings, &filename_setting,
+			       filename, sizeof ( filename ) );
+	if ( filename[0] )
+		printf ( "Filename: %s\n", filename );
+
+	return parse_next_server_and_filename ( next_server, filename );
+}
+
+/**
+ * Fetch root-path setting into a URI
+ *
+ * @v settings		Settings block
+ * @ret uri		URI, or NULL on failure
+ */
+static struct uri * fetch_root_path ( struct settings *settings ) {
+	char root_path[256];
+
+	/* Fetch root-path setting */
+	fetch_string_setting ( settings, &root_path_setting,
+			       root_path, sizeof ( root_path ) );
+	if ( root_path[0] )
+		printf ( "Root path: %s\n", root_path );
+
+	return parse_uri ( root_path );
+}
+
+/**
+ * Check whether or not we have a usable PXE menu
+ *
+ * @ret have_menu	A usable PXE menu is present
+ */
+static int have_pxe_menu ( void ) {
 	struct setting vendor_class_id_setting
 		= { .tag = DHCP_VENDOR_CLASS_ID };
 	struct setting pxe_discovery_control_setting
@@ -240,8 +277,28 @@ int netboot ( struct net_device *netdev ) {
 	struct setting pxe_boot_menu_setting
 		= { .tag = DHCP_PXE_BOOT_MENU };
 	char buf[256];
-	struct in_addr next_server;
 	unsigned int pxe_discovery_control;
+
+	fetch_string_setting ( NULL, &vendor_class_id_setting,
+			       buf, sizeof ( buf ) );
+	pxe_discovery_control =
+		fetch_uintz_setting ( NULL, &pxe_discovery_control_setting );
+
+	return ( ( strcmp ( buf, "PXEClient" ) == 0 ) &&
+		 setting_exists ( NULL, &pxe_boot_menu_setting ) &&
+		 ( ! ( ( pxe_discovery_control & PXEBS_SKIP ) &&
+		       setting_exists ( NULL, &filename_setting ) ) ) );
+}
+
+/**
+ * Boot from a network device
+ *
+ * @v netdev		Network device
+ * @ret rc		Return status code
+ */
+int netboot ( struct net_device *netdev ) {
+	struct uri *filename;
+	struct uri *root_path;
 	int rc;
 
 	/* Close all other network devices */
@@ -249,44 +306,42 @@ int netboot ( struct net_device *netdev ) {
 
 	/* Open device and display device status */
 	if ( ( rc = ifopen ( netdev ) ) != 0 )
-		return rc;
+		goto err_ifopen;
 	ifstat ( netdev );
 
 	/* Configure device via DHCP */
 	if ( ( rc = dhcp ( netdev ) ) != 0 )
-		return rc;
+		goto err_dhcp;
 	route();
 
 	/* Try PXE menu boot, if applicable */
-	fetch_string_setting ( NULL, &vendor_class_id_setting,
-			       buf, sizeof ( buf ) );
-	pxe_discovery_control =
-		fetch_uintz_setting ( NULL, &pxe_discovery_control_setting );
-	if ( ( strcmp ( buf, "PXEClient" ) == 0 ) &&
-	     setting_exists ( NULL, &pxe_boot_menu_setting ) &&
-	     ( ! ( ( pxe_discovery_control & PXEBS_SKIP ) &&
-		   setting_exists ( NULL, &filename_setting ) ) ) ) {
+	if ( have_pxe_menu() ) {
 		printf ( "Booting from PXE menu\n" );
-		return pxe_menu_boot ( netdev );
+		rc = pxe_menu_boot ( netdev );
+		goto err_pxe_menu_boot;
 	}
 
-	/* Try to download and boot whatever we are given as a filename */
-	fetch_ipv4_setting ( NULL, &next_server_setting, &next_server );
-	fetch_string_setting ( NULL, &filename_setting, buf, sizeof ( buf ) );
-	if ( buf[0] ) {
-		printf ( "Booting from filename \"%s\"\n", buf );
-		return boot_next_server_and_filename ( next_server, buf );
-	}
-	
-	/* No filename; try the root path */
-	fetch_string_setting ( NULL, &root_path_setting, buf, sizeof ( buf ) );
-	if ( buf[0] ) {
-		printf ( "Booting from root path \"%s\"\n", buf );
-		return boot_root_path ( buf );
-	}
-
-	printf ( "No filename or root path specified\n" );
-	return -ENOENT;
+	/* Fetch next server, filename and root path */
+	filename = fetch_next_server_and_filename ( NULL );
+	if ( ! filename )
+		goto err_filename;
+	root_path = fetch_root_path ( NULL );
+	if ( ! root_path )
+		goto err_root_path;
+
+	/* Boot using next server, filename and root path */
+	if ( ( rc = uriboot ( filename, root_path ) ) != 0 )
+		goto err_uriboot;
+
+ err_uriboot:
+	uri_put ( root_path );
+ err_root_path:
+	uri_put ( filename );
+ err_filename:
+ err_pxe_menu_boot:
+ err_dhcp:
+ err_ifopen:
+	return rc;
 }
 
 /**