package/mtd: add option for fixing seama images

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>

SVN-Revision: 33841

1 files changed, 179 insertions, 0 deletions

diff --git a/package/mtd/src/seama.c b/package/mtd/src/seama.c
new file mode 100644
index 0000000..b0c8bf3
--- /dev/null
+++ b/package/mtd/src/seama.c
@@ -0,0 +1,179 @@
+/*
+ * seama.c
+ *
+ * Copyright (C) 2011-2012 Gabor Juhos <juhosg@openwrt.org>
+ *
+ * Based on the trx fixup code:
+ *   Copyright (C) 2005 Mike Baker
+ *   Copyright (C) 2008 Felix Fietkau <nbd@openwrt.org>
+ *
+ * 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 <stdio.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <string.h>
+#include <errno.h>
+#include <arpa/inet.h>
+
+#include <sys/ioctl.h>
+#include <mtd/mtd-user.h>
+#include "mtd.h"
+#include "seama.h"
+#include "md5.h"
+
+#if __BYTE_ORDER == __BIG_ENDIAN
+#define STORE32_LE(X)           ((((X) & 0x000000FF) << 24) | (((X) & 0x0000FF00) << 8) | (((X) & 0x00FF0000) >> 8) | (((X) & 0xFF000000) >> 24))
+#elif __BYTE_ORDER == __LITTLE_ENDIAN
+#define STORE32_LE(X)           (X)
+#else
+#error unknown endianness!
+#endif
+
+ssize_t pread(int fd, void *buf, size_t count, off_t offset);
+ssize_t pwrite(int fd, const void *buf, size_t count, off_t offset);
+
+int
+seama_fix_md5(char *buf, size_t len)
+{
+	struct seama_hdr *shdr;
+	char *data;
+	size_t msize;
+	size_t isize;
+	MD5_CTX ctx;
+	unsigned char digest[16];
+	int i;
+
+	if (len < sizeof(struct seama_hdr))
+		return -1;
+
+	shdr = (struct seama_hdr *) buf;
+	if (shdr->magic != htonl(SEAMA_MAGIC)) {
+		fprintf(stderr, "no SEAMA header found\n");
+		return -1;
+	}
+
+	isize = ntohl(shdr->size);
+	msize = ntohs(shdr->metasize);
+	if (isize == 0) {
+		/* the image contains no checksum */
+		return -1;
+	}
+
+	len -= sizeof(struct seama_hdr) + sizeof(digest) + msize;
+	if (isize > len)
+		isize = len;
+
+	data = buf + sizeof(struct seama_hdr) + sizeof(digest) + msize;
+
+	MD5_Init(&ctx);
+	MD5_Update(&ctx, data, isize);
+	MD5_Final(digest, &ctx);
+
+	if (!memcmp(digest, &buf[sizeof(struct seama_hdr)], sizeof(digest))) {
+		if (quiet < 2)
+			fprintf(stderr, "the header is fixed already\n");
+		return -1;
+	}
+
+	if (quiet < 2) {
+		fprintf(stderr, "new size:%u, new MD5: ", isize);
+		for (i = 0; i < sizeof(digest); i++)
+			fprintf(stderr, "%02x", digest[i]);
+
+		fprintf(stderr, "\n");
+	}
+
+	/* update the size in the image */
+	shdr->size = htonl(isize);
+
+	/* update the checksum in the image */
+	for (i = 0; i < sizeof(digest); i++)
+		buf[sizeof(struct seama_hdr) + i] = digest[i];
+
+	return 0;
+}
+
+int
+mtd_fixseama(const char *mtd, size_t offset)
+{
+	int fd;
+	char *buf;
+	ssize_t res;
+	size_t block_offset;
+
+	if (quiet < 2)
+		fprintf(stderr, "Trying to fix SEAMA header in %s at 0x%x...\n",
+			mtd, offset);
+
+	block_offset = offset & ~(erasesize - 1);
+	offset -= block_offset;
+
+	fd = mtd_check_open(mtd);
+	if(fd < 0) {
+		fprintf(stderr, "Could not open mtd device: %s\n", mtd);
+		exit(1);
+	}
+
+	if (block_offset + erasesize > mtdsize) {
+		fprintf(stderr, "Offset too large, device size 0x%x\n",
+			mtdsize);
+		exit(1);
+	}
+
+	buf = malloc(mtdsize);
+	if (!buf) {
+		perror("malloc");
+		exit(1);
+	}
+
+	res = pread(fd, buf, mtdsize, block_offset);
+	if (res != mtdsize) {
+		perror("pread");
+		exit(1);
+	}
+
+	if (seama_fix_md5(buf, mtdsize))
+		goto out;
+
+	if (mtd_erase_block(fd, block_offset)) {
+		fprintf(stderr, "Can't erease block at 0x%x (%s)\n",
+			block_offset, strerror(errno));
+		exit(1);
+	}
+
+	if (quiet < 2)
+		fprintf(stderr, "Rewriting block at 0x%x\n", block_offset);
+
+	if (pwrite(fd, buf, erasesize, block_offset) != erasesize) {
+		fprintf(stderr, "Error writing block (%s)\n", strerror(errno));
+		exit(1);
+	}
+
+	if (quiet < 2)
+		fprintf(stderr, "Done.\n");
+
+out:
+	close (fd);
+	sync();
+
+	return 0;
+}
+