imd: add support for checksum generation/verification

Add a new imd type "checksum". This type consists of the CRC32 checksum
of the whole barebox image minus the checksum itself.
The checksum can be written to the imd field with the bareboximd host-tool.
It can be verified with said tool or with "imd" on the target.

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 34 insertions, 0 deletions

diff --git a/scripts/bareboximd.c b/scripts/bareboximd.c
index 5ef91831c4..cf1b8f693a 100644
--- a/scripts/bareboximd.c
+++ b/scripts/bareboximd.c
@@ -33,6 +33,7 @@
 #include <errno.h>
 #include <stdarg.h>
 #include <linux/err.h>
+#include <linux/kernel.h>
 
 #include "../include/image-metadata.h"
 
@@ -57,6 +58,35 @@ int imd_command_setenv(const char *variable_name, const char *value)
 	return -EINVAL;
 }
 
+static int write_file(const char *filename, const void *buf, size_t size)
+{
+	int fd, ret;
+	int now;
+
+	fd = open(filename, O_WRONLY | O_TRUNC | O_CREAT);
+	if (fd < 0)
+		return fd;
+
+	while (size) {
+		now = write(fd, buf, size);
+		if (now == 0) {
+			errno = ENOSPC;
+			return -1;
+		}
+		if (now < 0)
+			return now;
+		size -= now;
+		buf += now;
+	}
+
+	close(fd);
+
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
 static int read_file_2(const char *filename, size_t *size, void **outbuf, size_t max_size)
 {
 	off_t fsize;
@@ -129,6 +159,8 @@ static unsigned long simple_strtoul(const char *cp, char **endp, unsigned int ba
 	return strtoul(cp, endp, base);
 }
 
+#include "../include/xfuncs.h"
+#include "../crypto/crc32.c"
 #include "../common/imd.c"
 
 static void usage(const char *prgname)
@@ -140,6 +172,8 @@ static void usage(const char *prgname)
 "Options:\n"
 "-t <type>    only show information of <type>\n"
 "-n <no>      for tags with multiple strings only show string <no>\n"
+"-V           Verify checksum of FILE\n"
+"-c           Create checksum for FILE and write it to the crc32 tag\n"
 "\n"
 "Without options all information available is printed. Valid types are:\n"
 "release, build, model, of_compatible\n",