[PATCH] commands/digest: add verify support

[Eric Bénard]

From: Hubert Feurstein <h.feurstein at gmail.com>

Signed-off-by: Hubert Feurstein <h.feurstein at gmail.com>
[EB]: reworked based on Sascha's comments and tested with md5sum
Signed-off-by: Eric Bénard <eric at eukrea.com>
---
 commands/digest.c | 120 +++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 110 insertions(+), 10 deletions(-)

diff --git a/commands/digest.c b/commands/digest.c
index 092fda2..2a982e5 100644
--- a/commands/digest.c
+++ b/commands/digest.c
@@ -23,26 +23,99 @@
 #include <fcntl.h>
 #include <errno.h>
 #include <xfuncs.h>
+#include <libfile.h>
 #include <malloc.h>
 #include <digest.h>
+#include <linux/ctype.h>
+#include <getopt.h>
+
+static inline unsigned char parse_hexchar(char c)
+{
+	if (!isxdigit(c))
+		return 0;
+
+	return isdigit(c) ? (c - '0') : ((islower(c) ? toupper(c) : c) - 'A' + 0xA);
+}
+
+static inline unsigned char parse_hexbyte(const char *p)
+{
+	return (parse_hexchar(*p) << 4) | parse_hexchar(*(p + 1));
+}
+
+static unsigned char *parse_hash(int hash_len, const char *hexstr)
+{
+	int i;
+	unsigned char *p;
+
+	p = calloc(hash_len, sizeof(unsigned char));
+	if (!p) {
+		perror("calloc");
+		return NULL;
+	}
+
+	for (i = 0; i < hash_len; i++)
+		p[i] = parse_hexbyte(&hexstr[i * 2]);
+
+	return p;
+}
 
 static int do_digest(char *algorithm, int argc, char *argv[])
 {
 	struct digest *d;
 	int ret = 0;
 	int i;
-	unsigned char *hash;
+	unsigned char *hash = NULL;
+	int opt;
+	unsigned char *verify_hash = NULL;
+	int verify = 0;
+	int min_argc = 2;
+	int len = 0;
+	ssize_t bufsz;
 
 	d = digest_get_by_name(algorithm);
 	BUG_ON(!d);
 
-	if (argc < 2)
-		return COMMAND_ERROR_USAGE;
+	while ((opt = getopt(argc, argv, "v:V:")) > 0) {
+		switch (opt) {
+		case 'v':
+			verify++;
+			free(verify_hash);
+			hash = xstrdup(optarg);
+			len = strlen(hash);
+			break;
+		case 'V':
+			verify++;
+			free(verify_hash);
+			hash = read_file(optarg, &bufsz);
+			len = bufsz;
+			break;
+		default:
+			ret = COMMAND_ERROR_USAGE;
+			goto out;
+		}
+
+		if (verify == 1 && (d->length * 2) <= len && hash != NULL) {
+			min_argc += 2;
+			verify_hash = parse_hash(d->length, hash);
+			if (!verify_hash)
+				return -ENOMEM;
+			free(hash);
+		} else
+			return COMMAND_ERROR_USAGE;
+	}
+
+	if (argc < min_argc) {
+		ret = COMMAND_ERROR_USAGE;
+		goto out;
+	}
+
+	argv += min_argc - 2;
 
 	hash = calloc(d->length, sizeof(unsigned char));
 	if (!hash) {
 		perror("calloc");
-		return COMMAND_ERROR_USAGE;
+		ret = -ENOMEM;
+		goto out;
 	}
 
 	argv++;
@@ -60,17 +133,32 @@ static int do_digest(char *algorithm, int argc, char *argv[])
 		if (digest_file_window(d, filename, hash, start, size) < 0) {
 			ret = 1;
 		} else {
-			for (i = 0; i < d->length; i++)
+			for (i = 0; i < d->length; i++) {
 				printf("%02x", hash[i]);
+				if (verify > 0 && hash[i] != verify_hash[i])
+					verify = -1;
+			}
 
-			printf("  %s\t0x%08llx ... 0x%08llx\n",
+			printf("  %s\t0x%08llx ... 0x%08llx",
 				filename, start, start + size);
+
+			if (verify < 0) {
+				printf(" ** ERROR ** ");
+				ret = 1;
+			}
+
+			printf("\n");
+
+			if (verify)
+				break;
 		}
 
 		argv++;
 	}
 
+out:
 	free(hash);
+	free(verify_hash);
 
 	return ret;
 }
@@ -84,12 +172,15 @@ static int do_md5(int argc, char *argv[])
 
 BAREBOX_CMD_HELP_START(md5sum)
 BAREBOX_CMD_HELP_TEXT("Calculate a MD5 digest over a FILE or a memory area.")
+BAREBOX_CMD_HELP_TEXT("Options:")
+BAREBOX_CMD_HELP_OPT ("-v hash",     "verify")
+BAREBOX_CMD_HELP_OPT ("-V hash-file", "verify hash file")
 BAREBOX_CMD_HELP_END
 
 BAREBOX_CMD_START(md5sum)
 	.cmd		= do_md5,
 	BAREBOX_CMD_DESC("calculate MD5 checksum")
-	BAREBOX_CMD_OPTS("FILE|AREA...")
+	BAREBOX_CMD_OPTS("[-vV] FILE|AREA...")
 	BAREBOX_CMD_GROUP(CMD_GRP_FILE)
 	BAREBOX_CMD_HELP(cmd_md5sum_help)
 BAREBOX_CMD_END
@@ -105,12 +196,15 @@ static int do_sha1(int argc, char *argv[])
 
 BAREBOX_CMD_HELP_START(sha1sum)
 BAREBOX_CMD_HELP_TEXT("Calculate a SHA1 digest over a FILE or a memory area.")
+BAREBOX_CMD_HELP_TEXT("Options:")
+BAREBOX_CMD_HELP_OPT ("-v hash",     "verify")
+BAREBOX_CMD_HELP_OPT ("-V hash-file", "verify hash file")
 BAREBOX_CMD_HELP_END
 
 BAREBOX_CMD_START(sha1sum)
 	.cmd		= do_sha1,
 	BAREBOX_CMD_DESC("calculate SHA1 digest")
-	BAREBOX_CMD_OPTS("FILE|AREA")
+	BAREBOX_CMD_OPTS("[-vV] FILE|AREA")
 	BAREBOX_CMD_GROUP(CMD_GRP_FILE)
 	BAREBOX_CMD_HELP(cmd_sha1sum_help)
 BAREBOX_CMD_END
@@ -126,12 +220,15 @@ static int do_sha224(int argc, char *argv[])
 
 BAREBOX_CMD_HELP_START(sha224sum)
 BAREBOX_CMD_HELP_TEXT("Calculate a SHA224 digest over a FILE or a memory area.")
+BAREBOX_CMD_HELP_TEXT("Options:")
+BAREBOX_CMD_HELP_OPT ("-v hash",     "verify")
+BAREBOX_CMD_HELP_OPT ("-V hash-file", "verify hash file")
 BAREBOX_CMD_HELP_END
 
 BAREBOX_CMD_START(sha224sum)
 	.cmd		= do_sha224,
 	BAREBOX_CMD_DESC("calculate SHA224 digest")
-	BAREBOX_CMD_OPTS("FILE|AREA")
+	BAREBOX_CMD_OPTS("[-vV] FILE|AREA")
 	BAREBOX_CMD_GROUP(CMD_GRP_FILE)
 	BAREBOX_CMD_HELP(cmd_sha224sum_help)
 BAREBOX_CMD_END
@@ -147,12 +244,15 @@ static int do_sha256(int argc, char *argv[])
 
 BAREBOX_CMD_HELP_START(sha256sum)
 BAREBOX_CMD_HELP_TEXT("Calculate a SHA256 digest over a FILE or a memory area.")
+BAREBOX_CMD_HELP_TEXT("Options:")
+BAREBOX_CMD_HELP_OPT ("-v hash",     "verify")
+BAREBOX_CMD_HELP_OPT ("-V hash-file", "verify hash file")
 BAREBOX_CMD_HELP_END
 
 BAREBOX_CMD_START(sha256sum)
 	.cmd		= do_sha256,
 	BAREBOX_CMD_DESC("calculate SHA256 digest")
-	BAREBOX_CMD_OPTS("FILE|AREA")
+	BAREBOX_CMD_OPTS("[-vV] FILE|AREA")
 	BAREBOX_CMD_GROUP(CMD_GRP_FILE)
 	BAREBOX_CMD_HELP(cmd_sha256sum_help)
 BAREBOX_CMD_END
-- 
1.9.3