[U-Boot] [PATCH] mkenvimage: Handle text files with length that exceed env size

[Joe Hershberger]

From: Brian McFarland <bmcfarland at rldrake.com>

The current head revision of mkenvimage
(e72be8947e129f5ab274c0a9f235d2cc0014b2ea) will prevent you from
creating an env image from a text file that is larger than the env
length specified by the '-s' option.  That doesn't make sense given that
the tool now allows comments and blank lines.  This patch removes that
limitation and allows longer text files to be used.

Signed-off-by: Brian McFarland <bmcfarland at rldrake.com>
Signed-off-by: Joe Hershberger <joe.hershberger at ni.com>
---

Converted to a proper patch for the mailing list to be able to process.

 tools/mkenvimage.c | 34 +++++++++++++++++++++++++++-------
 1 file changed, 27 insertions(+), 7 deletions(-)

diff --git a/tools/mkenvimage.c b/tools/mkenvimage.c
index 6971b91..f1f602a 100644
--- a/tools/mkenvimage.c
+++ b/tools/mkenvimage.c
@@ -214,14 +214,13 @@ int main(int argc, char **argv)
 		}
 		ret = close(txt_fd);
 	}
-	/* The +1 is for the additionnal ending \0. See below. */
-	if (filesize + 1 > envsize) {
-		fprintf(stderr, "The input file is larger than the environment partition size\n");
-		return EXIT_FAILURE;
-	}
 
-	/* Replace newlines separating variables with \0 */
-	for (fp = 0, ep = 0 ; fp < filesize ; fp++) {
+	/*
+	 * Parse one byte at a time until reaching the end of the file OR until
+	 * the environment fills up. Check ep against envsize - 1 to allow for
+	 * an extra trailing '\0'.
+	 */
+	for (fp = 0, ep = 0 ; fp < filesize && ep < envsize - 1; fp++) {
 		if (filebuf[fp] == '\n') {
 			if (fp == 0 || filebuf[fp-1] == '\n') {
 				/*
@@ -250,6 +249,27 @@ int main(int argc, char **argv)
 		}
 	}
 	/*
+	 * If there are more bytes in the file still, it means the env filled up
+	 * before parsing the whole file.  Eat comments & whitespace here to see
+	 * if there was anything meaningful left in the file, and if so, throw
+	 * an error and exit.
+	 */
+	for (; fp < filesize; fp++) {
+		if (filebuf[fp] == '\n') {
+			if (fp == 0 || filebuf[fp-1] == '\n') {
+				/* Ignore blank lines */
+				continue;
+			}
+		} else if ((fp == 0 || filebuf[fp-1] == '\n') &&
+			   filebuf[fp] == '#') {
+			while (++fp < filesize && filebuf[fp] != '\n')
+				continue;
+		} else {
+			fprintf(stderr, "The environment file is too large for the target environment storage\n");
+			return EXIT_FAILURE;
+		}
+	}
+	/*
 	 * Make sure there is a final '\0'
 	 * And do it again on the next byte to mark the end of the environment.
 	 */
-- 
1.7.11.5