[sanboot] Extend the "keep-san" option to non-iSCSI SAN protocols

This disgustingly ugly hack just keeps getting worse.

src/arch/i386/interface/pcbios/aoeboot.c

 	rc = int13_boot ( drive.drive );
 	printf ( "Boot failed\n" );
 
+	/* Leave drive registered, if instructed to do so */
+	if ( keep_san() )
+		return rc;
+
 	printf ( "Unregistering BIOS drive %#02x\n", drive.drive );
 	unregister_int13_drive ( &drive );
 

src/arch/i386/interface/pcbios/ib_srpboot.c

 	rc = int13_boot ( drive->drive );
 	printf ( "Boot failed\n" );
 
+	/* Leave drive registered, if instructed to do so */
+	if ( keep_san() )
+		return rc;
+
 	printf ( "Unregistering BIOS drive %#02x\n", drive->drive );
 	unregister_int13_drive ( drive );
 

src/arch/i386/interface/pcbios/iscsiboot.c

 #include <stdio.h>
 #include <errno.h>
 #include <gpxe/iscsi.h>
-#include <gpxe/settings.h>
-#include <gpxe/dhcp.h>
 #include <gpxe/netdevice.h>
 #include <gpxe/ibft.h>
-#include <gpxe/init.h>
 #include <gpxe/sanboot.h>
 #include <int13.h>
-#include <usr/autoboot.h>
 
 FILE_LICENCE ( GPL2_OR_LATER );
 
-struct setting keep_san_setting __setting = {
-	.name = "keep-san",
-	.description = "Preserve SAN connection",
-	.tag = DHCP_EB_KEEP_SAN,
-	.type = &setting_type_int8,
-};
-
 static int iscsiboot ( const char *root_path ) {
 	struct scsi_device *scsi;
 	struct int13_drive *drive;
-	int keep_san;
 	int rc;
 
 	scsi = zalloc ( sizeof ( *scsi ) );
 	printf ( "Boot failed\n" );
 
 	/* Leave drive registered, if instructed to do so */
-	keep_san = fetch_intz_setting ( NULL, &keep_san_setting );
-	if ( keep_san ) {
-		printf ( "Preserving connection to SAN disk\n" );
-		shutdown_exit_flags |= SHUTDOWN_KEEP_DEVICES;
+	if ( keep_san() )
 		return rc;
-	}
 
 	printf ( "Unregistering BIOS drive %#02x\n", drive->drive );
 	unregister_int13_drive ( drive );

src/arch/i386/interface/pcbios/keepsan.c

+#include <stdint.h>
+#include <stdio.h>
+#include <gpxe/settings.h>
+#include <gpxe/dhcp.h>
+#include <gpxe/init.h>
+#include <gpxe/sanboot.h>
+#include <usr/autoboot.h>
+
+struct setting keep_san_setting __setting = {
+	.name = "keep-san",
+	.description = "Preserve SAN connection",
+	.tag = DHCP_EB_KEEP_SAN,
+	.type = &setting_type_int8,
+};
+
+int keep_san ( void ) {
+	int keep_san;
+
+	keep_san = fetch_intz_setting ( NULL, &keep_san_setting );
+	if ( ! keep_san )
+		return 0;
+
+	printf ( "Preserving connection to SAN disk\n" );
+	shutdown_exit_flags |= SHUTDOWN_KEEP_DEVICES;
+	return 1;
+}

src/include/gpxe/sanboot.h

 
 #define __sanboot_protocol __table_entry ( SANBOOT_PROTOCOLS, 01 )
 
+extern int keep_san ( void );
+
 #endif /* _GPXE_SANBOOT_H */