--- /dev/null
+/*
+ * fs_swap.c - A filesystem driver to detect swapspace on a partition.
+ *
+ * Copyright 2009 Tony Breeds, IBM Corporation
+ *
+ * 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
+ * (at your option) 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include "ctype.h"
+#include "types.h"
+#include "stddef.h"
+#include "stdlib.h"
+#include "file.h"
+#include "prom.h"
+#include "string.h"
+#include "partition.h"
+#include "fs.h"
+#include "errors.h"
+#include "debug.h"
+#include "bootinfo.h"
+
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0]))
+#define BLKCOUNT 2
+
+static struct {
+ char *magic;
+ int len, offset;
+} signatures[] = {
+ { "SWAP-SPACE", 10, 0xff6}, /* 4k Pages */
+ { "SWAPSPACE2", 10, 0xff6},
+ { "SWAP-SPACE", 10, 0xfff6}, /* 64k Pages */
+ { "SWAPSPACE2", 10, 0xfff6},
+};
+
+/* swap_open: Open a block device and look for swapspace magic.
+ * If we find a valid signature the retuning FILE_ERR_NOTFOUND means
+ * that no other filsystem drivers will check this partition */
+static int
+swap_open(struct boot_file_t* file, struct partition_t* part,
+ struct boot_fspec_t* fspec)
+{
+ int i;
+ unsigned char *buffer;
+ /* Make static to move into the BSS rather then the stack */
+ static unsigned char device_name[1024];
+
+ DEBUG_ENTER;
+ DEBUG_OPEN;
+
+ if (file->device_kind != FILE_DEVICE_BLOCK || part == NULL) {
+ DEBUG_LEAVE(FILE_ERR_BADDEV);
+ return FILE_ERR_BADDEV;
+ }
+
+ /* We assume that device is "short" and is correctly NULL terminsated */
+ strncpy(device_name, fspec->dev, 1020);
+ if (_machine != _MACH_bplan)
+ strcat(device_name, ":0");
+
+ DEBUG_F("Opening device: %s\n", device_name);
+ file->of_device = prom_open(device_name);
+ if (file->of_device == NULL) {
+ DEBUG_LEAVE(FILE_IOERR);
+ return FILE_IOERR;
+ }
+ DEBUG_F("file->of_device = %p\n", file->of_device);
+
+ /* If the signature is right on a block boundry we may need two blocks,
+ * so lets just allocate room for them now */
+ buffer = malloc(sizeof(unsigned char) * part->blocksize * BLKCOUNT);
+ if (buffer == NULL) {
+ DEBUG_LEAVE("malloc for disk buffer failed\n");
+ return FILE_ERR_NOMEM;
+ }
+
+ for(i=0; i< ARRAY_SIZE(signatures); i++) {
+ int blk = part->part_start + (signatures[i].offset / part->blocksize);
+ int rc = prom_readblocks(file->of_device, blk, BLKCOUNT, buffer);
+
+ /* FIXME: going past partition length */
+ DEBUG_F("Looking for %s @ offset 0x%x, rc == %d, blk=0x%x\n",
+ signatures[i].magic, signatures[i].offset, rc, blk);
+
+ if (memcmp(&buffer[signatures[i].offset % part->blocksize],
+ signatures[i].magic, signatures[i].len) == 0) {
+ free(buffer);
+ DEBUG_F("Found a swap signature\n");
+ DEBUG_LEAVE(FILE_ERR_NOTFOUND);
+ return FILE_ERR_NOTFOUND;
+ }
+ }
+
+ free(buffer);
+ prom_close(file->of_device);
+ file->of_device = NULL;
+
+ DEBUG_LEAVE(FILE_ERR_BAD_FSYS);
+ return FILE_ERR_BAD_FSYS;
+}
+
+struct fs_t swap_filesystem =
+{
+ "swap signature checker",
+ swap_open,
+ NULL,
+ NULL,
+ NULL,
+};
+
+/*
+ * Local variables:
+ * c-file-style: "k&r"
+ * c-basic-offset: 5
+ * End:
+ */