blkid: add -n <list> option

This option allows to restrict low-level probing to the defined list
of superbocks (filesystems or RAIDs). For example:

	blkid -p -n ext3,ext4,vfat /dev/sda1
or
	blkid -p -n novfat /dev/sda1

Signed-off-by: Karel Zak <kzak@redhat.com>

misc-utils/blkid.8

@@ -43,6 +43,8 @@ blkid \- command\-line utility to locate/print block device attributes
 .RB [ \-s
 .IR tag ]
 .in +9
+.RB [ \-n
+.IR list ]
 .RB [ \-u
 .IR list ]
 .I device
@@ -104,6 +106,21 @@ from e2fsprogs use the \fB-L\fR option as a
 synonym to the \fB-o list\fR option. For better portability use "-l -o device
 -t LABEL=<label>" and "-o list" in your scripts rather than -L option.
 .TP
+.B \-n " list "
+Restrict probing functions to defined (comma separated) list of superblock types (names).
+The list can be prefixed with "no" to specify the types which should be ignored.
+For example:
+.sp
+  blkid -p -n vfat,ext3,ext4 /dev/sda1
+.sp
+probes for vfat, ext3 and ext4 filesystems, and
+.sp
+  blkid -p -u nominix /dev/sda1
+.sp
+probes for all supported formats exclude minix filesystem. This option is
+useful with
+\fB-p\fR only.
+.TP
 .B \-u " list "
 Restrict probing functions to defined (comma separated) list of "usage" types.
 Supported usage types are: filesystem, raid, crypto and other. The list can be

misc-utils/blkid.c

@@ -76,6 +76,7 @@ static void usage(int error)
 		"  -S <bytes>  overwrite device size\n"
 		"  -O <bytes>  probe at the given offset\n"
 		"  -u <list>   filter by \"usage\" (e.g. -u filesystem,raid)\n"
+		"  -n <list>   filter by filesystem type (e.g. -n vfat,ext3)\n"
 		"\n",
 				progname);
 
@@ -532,17 +533,13 @@ static int list_to_usage(const char *list, int *flag)
 		*flag = BLKID_FLTR_NOTIN;
 		p += 2;
 	}
-
 	if (!p || !*p)
 		goto err;
-
 	while(p) {
 		word = p;
-
 		p = strchr(p, ',');
 		if (p)
 			p++;
-
 		if (!strncmp(word, "filesystem", 10))
 			mask |= BLKID_USAGE_FILESYSTEM;
 		else if (!strncmp(word, "raid", 4))
@@ -555,7 +552,6 @@ static int list_to_usage(const char *list, int *flag)
 			goto err;
 	}
 	return mask;
-
 err:
 	*flag = 0;
 	fprintf(stderr, "unknown kerword in -u <list> argument: '%s'\n",
@@ -563,6 +559,59 @@ err:
 	exit(4);
 }
 
+/* converts comma separated list to types[] */
+static char **list_to_types(const char *list, int *flag)
+{
+	int i;
+	const char *p = list;
+	char **res;
+
+	if (p && strncmp(p, "no", 2) == 0) {
+		*flag = BLKID_FLTR_NOTIN;
+		p += 2;
+	}
+	if (!p || !*p) {
+		fprintf(stderr, "error: -u <list> argument is empty\n");
+		goto err;
+	}
+	for (i = 1; p && (p = strchr(p, ',')); i++, p++);
+
+	res = calloc(i + 1, sizeof(char *));
+	if (!res)
+		goto err_mem;
+	p = *flag & BLKID_FLTR_NOTIN ? list + 2 : list;
+	i = 0;
+
+	while(p) {
+		const char *word = p;
+		p = strchr(p, ',');
+		res[i] = p ? strndup(word, p - word) : strdup(word);
+		if (!res[i++])
+			goto err_mem;
+		if (p)
+			p++;
+	}
+	res[i] = NULL;
+	return res;
+err_mem:
+	fprintf(stderr, "out of memory\n");
+err:
+	*flag = 0;
+	free(res);
+	exit(4);
+}
+
+static void free_types_list(char *list[])
+{
+	char **n;
+
+	if (!list)
+		return;
+	for (n = list; *n; n++)
+		free(*n);
+	free(list);
+}
+
 int main(int argc, char **argv)
 {
 	blkid_cache cache = NULL;
@@ -572,6 +621,7 @@ int main(int argc, char **argv)
 	char *read = NULL;
 	char *write = NULL;
 	int fltr_usage = 0;
+	char **fltr_type = NULL;
 	int fltr_flag = BLKID_FLTR_ONLYIN;
 	unsigned int numdev = 0, numtag = 0;
 	int version = 0;
@@ -584,7 +634,7 @@ int main(int argc, char **argv)
 
 	show[0] = NULL;
 
-	while ((c = getopt (argc, argv, "c:f:ghlL:o:O:ps:S:t:u:U:w:v")) != EOF)
+	while ((c = getopt (argc, argv, "c:f:ghlL:n:o:O:ps:S:t:u:U:w:v")) != EOF)
 		switch (c) {
 		case 'c':
 			if (optarg && !*optarg)
@@ -599,7 +649,18 @@ int main(int argc, char **argv)
 			search_value = strdup(optarg);
 			search_type = strdup("LABEL");
 			break;
+		case 'n':
+			if (fltr_usage) {
+				fprintf(stderr, "error: -u and -n options are mutually exclusive\n");
+				exit(4);
+			}
+			fltr_type = list_to_types(optarg, &fltr_flag);
+			break;
 		case 'u':
+			if (fltr_type) {
+				fprintf(stderr, "error: -u and -n options are mutually exclusive\n");
+				exit(4);
+			}
 			fltr_usage = list_to_usage(optarg, &fltr_flag);
 			break;
 		case 'U':
@@ -733,6 +794,9 @@ int main(int argc, char **argv)
 		if (fltr_usage &&
 		    blkid_probe_filter_superblocks_usage(pr, fltr_flag, fltr_usage))
 			goto exit;
+		else if (fltr_type &&
+		    blkid_probe_filter_superblocks_type(pr, fltr_flag, fltr_type))
+			goto exit;
 
 		for (i = 0; i < numdev; i++)
 			err = lowprobe_device(pr, devices[i], show,
@@ -802,6 +866,7 @@ int main(int argc, char **argv)
 exit:
 	free(search_type);
 	free(search_value);
+	free_types_list(fltr_type);
 	if (!lowprobe && !eval)
 		blkid_put_cache(cache);
 	return err;