mkubootenv: Implement -n commandline option to disable CRC32 generation

1 files changed, 16 insertions, 9 deletions

diff --git a/mkubootenv/mkubootenv.c b/mkubootenv/mkubootenv.c
index 8e49cbb..26b5334 100644
--- a/mkubootenv/mkubootenv.c
+++ b/mkubootenv/mkubootenv.c
@@ -11,8 +11,8 @@
  *
  * The environment is preceeded by a 32 bit CRC over the data part.
  *
- * Copyright (c) 2009, Zurich University of Applied Sciences
- * Copyright (c) 2009, Tobias Klauser <klto@zhaw.ch>
+ * Copyright (c) 2009-2012, Zurich University of Applied Sciences
+ * Copyright (c) 2009-2012, Tobias Klauser <tklauser@distanz.ch>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
@@ -154,10 +154,9 @@ static void uboot_env_cleanup_file(struct file *f)
 		close(f->fd);
 }
 
-static void uboot_env_to_img(struct file *s, struct file *t)
+static void uboot_env_to_img(struct file *s, struct file *t, bool do_crc)
 {
 	uint8_t *p, *q, *end;
-	uint32_t *crc;
 
 	dbg("source file (env):       %s\n", s->name);
 	dbg("target image file (bin): %s\n", t->name);
@@ -179,8 +178,10 @@ static void uboot_env_to_img(struct file *s, struct file *t)
 		*p = 0;
 
 	/* now for the real CRC32 */
-	crc = (uint32_t *) t->ptr;
-	*crc = crc32(0, t->ptr + CRC32_SIZE, t->size - CRC32_SIZE);
+	if (do_crc) {
+		uint32_t *crc = (uint32_t *) t->ptr;
+		*crc = crc32(0, t->ptr + CRC32_SIZE, t->size - CRC32_SIZE);
+	}
 }
 
 static void uboot_img_to_env(struct file *s, struct file *t)
@@ -206,10 +207,12 @@ static void uboot_img_to_env(struct file *s, struct file *t)
 static void usage_and_exit(int status)
 {
 	printf("usage: mkubootenv [-s <size>] <source file> <target file>\n"
-	       "  -s <size>  set size of the target image file to <size> bytes. If <size> is\n"
+	       "  -s <size>  Set size of the target image file to <size> bytes. If <size> is\n"
 	       "             bigger than the source file, the target image gets padded with null\n"
 	       "             bytes. If <size> is smaller than the source file, an error is emitted.\n"
-	       "  -r         reverse operation: get plaintext env file (target) from binary image\n"
+	       "  -n         Disable CRC32 calculation. The CRC32 of the generated image will be\n"
+	       "             filled with zeros. This option is ignored in reverse mode.\n"
+	       "  -r         Reverse operation: get plaintext env file (target) from binary image\n"
 	       "             file (source)\n");
 	exit(status);
 }
@@ -220,6 +223,7 @@ int main(int argc, char **argv)
 	int status = EXIT_FAILURE;
 	ssize_t img_size = -1;
 	bool reverse = false;
+	bool do_crc = true;
 	struct file s, t;	/* source and target file */
 
 	if (argc < 2)
@@ -247,6 +251,9 @@ int main(int argc, char **argv)
 		case 'r':
 			reverse = true;
 			break;
+		case 'n':
+			do_crc = false;
+			break;
 		case 'h':
 			status = EXIT_SUCCESS;
 			/* fall through */
@@ -295,7 +302,7 @@ int main(int argc, char **argv)
 		if (uboot_env_prepare_target(&t))
 			goto cleanup_source;
 
-		uboot_env_to_img(&s, &t);
+		uboot_env_to_img(&s, &t, do_crc);
 	} else {
 		uint8_t *p;
 		uint8_t *end;