firmware-utils: jcgimage: add support for 4MiB+ images

The first version of this script allowed just 4Mb factory images.
With this patch is possible to set the maximum size of the payload.

For an 8Mb flash, the corresponding maxsize is:
8 * 1024 * 1024 - 5 * 64 * 1024 = 8388608 - 327680 = 8060928

If the -m argument is not set, the default maximum size will be
used for backward compatibility.

Signed-off-by: Davide Fioravanti <[email protected]>

tools/firmware-utils/src/jcgimage.c

@@ -2,6 +2,7 @@
  * jcgimage - Create a JCG firmware image
  *
  * Copyright (C) 2015 Reinhard Max <[email protected]>
+ * Copyright (C) 2019 Davide Fioravanti <[email protected]>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -45,6 +46,11 @@
  * requiring JTAG to revive the board. To prevent such bricking from
  * happening, this tool refuses to build such overlong images.
  *
+ * Using -m is possible to set the maximum size of the payload.
+ * Otherwise the default MAXSIZE will be used.
+ * For an 8Mb flash, the corresponding maxsize is:
+ * 8 * 1024 * 1024 - 5 * 64 * 1024 = 8388608 - 327680 = 8060928
+ *
  * Two more conditions have to be met for a JCG image to be accepted
  * as a valid update by the web interface of the stock firware:
  *
@@ -92,6 +98,7 @@
 #include <sys/mman.h>
 #include <arpa/inet.h>
 #include <assert.h>
+#include <inttypes.h>
 
 /*
  * JCG Firmware image header
@@ -292,8 +299,8 @@ craftcrc(uint32_t dcrc, uint8_t *buf, size_t len)
 void
 usage() {
 	fprintf(stderr, "Usage:\n"
-		"jcgimage -o outfile -u uImage [-v version]\n"
-		"jcgimage -o outfile -k kernel -f rootfs [-v version]\n");
+		"jcgimage -o outfile -u uImage [-m maxsize] [-v version]\n"
+		"jcgimage -o outfile -k kernel -f rootfs [-m maxsize] [-v version]\n");
 	exit(1);
 }
 
@@ -314,6 +321,8 @@ main(int argc, char **argv)
 	char *file1 = NULL;
 	char *file2 = NULL;
 	char *version = NULL;
+	size_t maxsize = MAXSIZE;
+	char *endptr;
 	int mode = MODE_UNKNOWN;
 	int fdo, fd1, fd2;
 	size_t size1, size2, sizeu, sizeo, off1, off2;
@@ -324,7 +333,7 @@ main(int argc, char **argv)
 	assert(sizeof(struct uimage_header) == 64);
 	set_source_date_epoch();
 
-	while ((c = getopt(argc, argv, "o:k:f:u:v:h")) != -1) {
+	while ((c = getopt(argc, argv, "o:k:f:u:v:m:h")) != -1) {
 		switch (c) {
 		case 'o':
 			imagefile = optarg;
@@ -349,6 +358,11 @@ main(int argc, char **argv)
 
 			mode = MODE_UIMAGE;
 			file1 = optarg;
+			break;
+		case 'm':
+			if (optarg != NULL)
+				maxsize = strtoimax(optarg, &endptr, 10);
+
 			break;
 		case 'v':
 			version = optarg;
@@ -385,8 +399,8 @@ main(int argc, char **argv)
 		sizeo = sizeof(*jh) + sizeu;
 	}
 
-	if (sizeo > MAXSIZE)
-		errx(1, "payload too large: %zd > %zd\n", sizeo, MAXSIZE);
+	if (sizeo > maxsize)
+		errx(1, "payload too large: %zd > %zd\n", sizeo, maxsize);
 
 
 	fdo = open(imagefile, O_RDWR | O_CREAT | O_TRUNC, 00644);