uuidgen: add support for hash-based UUIDs

Signed-off-by: Philip Prindeville <philipp@redfish-solutions.com>

2 files changed, 162 insertions, 9 deletions

diff --git a/misc-utils/uuidgen.1 b/misc-utils/uuidgen.1
index 56c2bc7bd..500e3124c 100644
--- a/misc-utils/uuidgen.1
+++ b/misc-utils/uuidgen.1
@@ -18,18 +18,41 @@ all UUIDs created on the local system,
 and among UUIDs created on other systems in the past
 and in the future.
 .PP
-There are two types of UUIDs which
+There are three types of UUIDs which
 .B uuidgen
-can generate: time-based UUIDs and random-based UUIDs.  By default
+can generate: time-based UUIDs, random-based UUIDs, and hash-based UUIDs.
+By default
 .B uuidgen
 will generate a random-based UUID if a high-quality random number
 generator is present.  Otherwise, it will choose a time-based UUID.
-It is possible to force the generation of one of these two
+It is possible to force the generation of one of these first two
 UUID types by using the
 .B \-r
 or
 .B \-t
 options.
+.PP
+The third type of UUID is generated with the
+.B \-m
+or
+.B \-s
+options (MD5 or SHA1, respectively), followed by
+.BR "\-n " \fInamespace
+and
+.BR "\-N " \fIname\fR.
+The \fInamespace\fR may either be a well-known UUID, or else
+an alias to one of the well-known UUIDs defined in RFC 4122, that is
+.BR @dns ,
+.BR @url ,
+.BR @oid ,
+or
+.BR @x500 .
+The \fIname\fR is an arbitrary string value.  The generated UUID is the
+digest of the concatentation of the namespace UUID and the name value, hashed
+with the MD5 or SHA1 algorithms.  It is, therefore, a predictable value
+which may be useful when UUIDs are being used as handles or nonces for
+more complex values or values which shouldn't be disclosed directly.
+See the RFC for more information.
 .SH OPTIONS
 .TP
 .BR \-r , " \-\-random"
@@ -47,13 +70,29 @@ Display help text and exit.
 .TP
 .BR \-V , " \-\-version"
 Display version information and exit.
+.TP
+.BR \-m , " \-\-md5"
+Use MD5 as the hash algorithm.
+.TP
+.BR \-s , " \-\-sha1"
+Use SHA1 as the hash algorith.
+.TP
+.BR \-n , " \-\-namespace " \fInamespace\fP
+Generate the hash with the \fInamespace\fP prefix.
+.TP
+.BR \-N , " \-\-name " \fIname\fR
+Generate the hash of the \fIname\fR.
+.TP
+.BR \-x , " \-\-hex"
+Interpret name \fIname\fR as a hexidecimal string.
 .SH "CONFORMING TO"
 OSF DCE 1.1
 .SH AUTHOR
 .B uuidgen
 was written by Andreas Dilger for libuuid.
 .SH SEE ALSO
-.BR libuuid (3)
+.BR libuuid (3),
+.B "RFC 4122"
 .SH AVAILABILITY
 The uuidgen command is part of the util-linux package and is available from
 https://www.kernel.org/pub/linux/utils/util-linux/.
diff --git a/misc-utils/uuidgen.c b/misc-utils/uuidgen.c
index ac950747d..c19706953 100644
--- a/misc-utils/uuidgen.c
+++ b/misc-utils/uuidgen.c
@@ -29,27 +29,75 @@ static void __attribute__((__noreturn__)) usage(void)
 	fputs(_("Create a new UUID value.\n"), out);
 
 	fputs(USAGE_OPTIONS, out);
-	fputs(_(" -r, --random     generate random-based uuid\n"), out);
-	fputs(_(" -t, --time       generate time-based uuid\n"), out);
+	fputs(_(" -r, --random        generate random-based uuid\n"), out);
+	fputs(_(" -t, --time          generate time-based uuid\n"), out);
+	fputs(_(" -n, --namespace ns  generate hash-based uuid in this namespace\n"), out);
+	fputs(_(" -N, --name name     generate hash-based uuid from this name\n"), out);
+	fputs(_(" -m, --md5           generate md5 hash\n"), out);
+	fputs(_(" -s, --sha1          generate sha1 hash\n"), out);
+	fputs(_(" -x, --hex           interpret name as hex string\n"), out);
 	fputs(USAGE_SEPARATOR, out);
 	printf(USAGE_HELP_OPTIONS(18));
 	printf(USAGE_MAN_TAIL("uuidgen(1)"));
 	exit(EXIT_SUCCESS);
 }
 
+static char *unhex(const char *value, size_t *valuelen)
+{
+	char c, *value2;
+	unsigned n, x;
+
+	if (*valuelen % 2 != 0) {
+badstring:
+		fprintf(stderr, "%s: not a valid hex string\n", program_invocation_short_name);
+		errtryhelp(EXIT_FAILURE);
+	}
+
+	value2 = malloc(*valuelen / 2 + 1);
+
+	for (x = n = 0; n < *valuelen; n++) {
+		c = value[n];
+		if ('0' <= c && c <= '9')
+			x += c - '0';
+		else if (('a' <= c && c <= 'f') || ('A' <= c && c <= 'F'))
+			x += (c - 'A' + 10) & 0xf;
+		else
+			goto badstring;
+
+		if (n % 2 == 0)
+			x *= 16;
+		else {
+			value2[n / 2] = x;
+			x = 0;
+		}
+	}
+	value2[n / 2] = '\0';
+
+	*valuelen = (n / 2);
+
+	return value2;
+}
+
 int
 main (int argc, char *argv[])
 {
 	int    c;
-	int    do_type = 0;
+	int    do_type = 0, is_hex = 0;
 	char   str[UUID_STR_LEN];
-	uuid_t uu;
+	char   *namespace = NULL, *name = NULL;
+	size_t namelen = 0;
+	uuid_t ns, uu;
 
 	static const struct option longopts[] = {
 		{"random", no_argument, NULL, 'r'},
 		{"time", no_argument, NULL, 't'},
 		{"version", no_argument, NULL, 'V'},
 		{"help", no_argument, NULL, 'h'},
+		{"namespace", required_argument, NULL, 'n'},
+		{"name", required_argument, NULL, 'N'},
+		{"md5", no_argument, NULL, 'm'},
+		{"sha1", no_argument, NULL, 's'},
+		{"hex", no_argument, NULL, 'x'},
 		{NULL, 0, NULL, 0}
 	};
 
@@ -58,7 +106,7 @@ main (int argc, char *argv[])
 	textdomain(PACKAGE);
 	atexit(close_stdout);
 
-	while ((c = getopt_long(argc, argv, "rtVh", longopts, NULL)) != -1)
+	while ((c = getopt_long(argc, argv, "rtVhn:N:msx", longopts, NULL)) != -1)
 		switch (c) {
 		case 't':
 			do_type = UUID_TYPE_DCE_TIME;
@@ -69,12 +117,53 @@ main (int argc, char *argv[])
 		case 'V':
 			printf(UTIL_LINUX_VERSION);
 			return EXIT_SUCCESS;
+		case 'n':
+			namespace = optarg;
+			break;
+		case 'N':
+			name = optarg;
+			break;
+		case 'm':
+			do_type = UUID_TYPE_DCE_MD5;
+			break;
+		case 's':
+			do_type = UUID_TYPE_DCE_SHA1;
+			break;
+		case 'x':
+			is_hex = 1;
+			break;
 		case 'h':
 			usage();
 		default:
 			errtryhelp(EXIT_FAILURE);
 		}
 
+	if (namespace) {
+		if (!name) {
+			fprintf(stderr, "%s: --namespace requires --name argument\n", program_invocation_short_name);
+			errtryhelp(EXIT_FAILURE);
+		}
+		if (do_type != UUID_TYPE_DCE_MD5 && do_type != UUID_TYPE_DCE_SHA1) {
+			fprintf(stderr, "%s: --namespace requires --md5 or --sha1\n", program_invocation_short_name);
+			errtryhelp(EXIT_FAILURE);
+		}
+	} else {
+		if (name) {
+			fprintf(stderr, "%s: --name requires --namespace argument\n", program_invocation_short_name);
+			errtryhelp(EXIT_FAILURE);
+		}
+		if (do_type == UUID_TYPE_DCE_MD5 || do_type == UUID_TYPE_DCE_SHA1) {
+			fprintf(stderr, "%s: --md5 or --sha1 require --namespace\n", program_invocation_short_name);
+			errtryhelp(EXIT_FAILURE);
+		}
+	}
+
+	if (name) {
+		namelen = strlen(name);
+		if (is_hex)
+			name = unhex(name, &namelen);
+	}
+
 	switch (do_type) {
 	case UUID_TYPE_DCE_TIME:
 		uuid_generate_time(uu);
@@ -82,6 +171,28 @@ main (int argc, char *argv[])
 	case UUID_TYPE_DCE_RANDOM:
 		uuid_generate_random(uu);
 		break;
+	case UUID_TYPE_DCE_MD5:
+	case UUID_TYPE_DCE_SHA1:
+		if (namespace[0] == '@' && namespace[1] != '\0') {
+			const uuid_t *uuidptr;
+
+			uuidptr = uuid_get_template(&namespace[1]);
+			if (uuidptr == NULL) {
+				fprintf(stderr, "%s: unknown namespace alias '%s'\n", program_invocation_short_name, namespace);
+				errtryhelp(EXIT_FAILURE);
+			}
+			memcpy(ns, *uuidptr, sizeof(ns));
+		} else {
+			if (uuid_parse(namespace, ns) != 0) {
+				fprintf(stderr, "%s: invalid uuid for namespace '%s'\n", program_invocation_short_name, namespace);
+				errtryhelp(EXIT_FAILURE);
+			}
+		}
+		if (do_type == UUID_TYPE_DCE_MD5)
+			uuid_generate_md5(uu, ns, name, namelen);
+		else
+			uuid_generate_sha1(uu, ns, name, namelen);
+		break;
 	default:
 		uuid_generate(uu);
 		break;
@@ -91,5 +202,8 @@ main (int argc, char *argv[])
 
 	printf("%s\n", str);
 
+	if (is_hex)
+		free(name);
+
 	return EXIT_SUCCESS;
 }