UBI-utils: add compare feature

This is a new feature for pfiflash, called "--compare". It allows the user
to simulate a pfiflash session without actually changing the flash
content. If the flash content is equal to the data in the pfif file,
pfiflash returns zero. A positive value is returned when the flash
content differs from the pfi file, which indicates that an update is
necessary. This feature is useful when a controller mounts an NFS share
during boot and has to determine if a pfi file stored on this share
contains a code update. Modified PDD values are also registered by the
compare feature.

Signed-off-by: Alexander Schmidt <alexs@linux.vnet.ibm.com>

1 files changed, 48 insertions, 0 deletions

diff --git a/ubi-utils/src/bootenv.c b/ubi-utils/src/bootenv.c
index ed15dc7..561d473 100644
--- a/ubi-utils/src/bootenv.c
+++ b/ubi-utils/src/bootenv.c
@@ -480,6 +480,54 @@ bootenv_write(FILE* fp, bootenv_t env)
 }
 
 int
+bootenv_compare(bootenv_t first, bootenv_t second)
+{
+	int rc;
+	size_t written_first, written_second;
+	char *buf_first, *buf_second;
+
+	if (first == NULL || second == NULL)
+		return -EINVAL;
+
+	buf_first = malloc(BOOTENV_MAXSIZE);
+	if (!buf_first)
+		return -ENOMEM;
+	buf_second = malloc(BOOTENV_MAXSIZE);
+	if (!buf_second) {
+		rc = -ENOMEM;
+		goto err;
+	}
+
+	rc = fill_output_buffer(first, buf_first, BOOTENV_MAXSIZE,
+			&written_first);
+	if (rc < 0)
+		goto err;
+	rc = fill_output_buffer(second, buf_second, BOOTENV_MAXSIZE,
+			&written_second);
+	if (rc < 0)
+		goto err;
+
+	if (written_first != written_second) {
+		rc = 1;
+		goto err;
+	}
+
+	rc = memcmp(buf_first, buf_second, written_first);
+	if (rc != 0) {
+		rc = 2;
+		goto err;
+	}
+
+err:
+	if (buf_first)
+		free(buf_first);
+	if (buf_second)
+		free(buf_second);
+
+	return rc;
+}
+
+int
 bootenv_size(bootenv_t env, size_t *size)
 {
 	int rc = 0;