losetup: fix util-linux compatibility

Added -a support. Also made sure -f works as follows:

losetup [-r] [-o offset] {-f|loopdev} file

Removed support for 'losetup -r' with no arguments.

Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

1 files changed, 65 insertions, 51 deletions

diff --git a/util-linux/losetup.c b/util-linux/losetup.c
index 21108d0..c697633 100644
--- a/util-linux/losetup.c
+++ b/util-linux/losetup.c
@@ -8,16 +8,16 @@
  */
 
 //usage:#define losetup_trivial_usage
-//usage:       "[-r] [-o OFS] LOOPDEV FILE - associate loop devices\n"
+//usage:       "[-r] [-o OFS] {-f|LOOPDEV} FILE - associate loop devices\n"
 //usage:       "	losetup -d LOOPDEV - disassociate\n"
-//usage:       "	losetup [-f] - show"
+//usage:       "	losetup -a - show status of  all\n"
+//usage:       "	losetup -f - show next available"
 //usage:#define losetup_full_usage "\n\n"
 //usage:       "	-o OFS	Start OFS bytes into FILE"
 //usage:     "\n	-r	Read-only"
-//usage:     "\n	-f	Show first free loop device"
+//usage:     "\n	-f	Show/find first free loop device"
 //usage:
 //usage:#define losetup_notes_usage
-//usage:       "No arguments will display all current associations.\n"
 //usage:       "One argument (losetup /dev/loop1) will display the current association\n"
 //usage:       "(if any), or disassociate it (with -d). The display shows the offset\n"
 //usage:       "and filename of the file the loop device is currently bound to.\n\n"
@@ -31,77 +31,91 @@ int losetup_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int losetup_main(int argc UNUSED_PARAM, char **argv)
 {
 	unsigned opt;
-	int n;
 	char *opt_o;
-	unsigned long long offset = 0;
+	char dev[LOOP_NAMESIZE];
 	enum {
 		OPT_d = (1 << 0),
 		OPT_o = (1 << 1),
 		OPT_f = (1 << 2),
-		OPT_r = (1 << 3), /* must be last */
+		OPT_a = (1 << 3),
+		OPT_r = (1 << 4), /* must be last */
 	};
 
-	/* max 2 args, -d,-o,-f opts are mutually exclusive */
-	opt_complementary = "?2:d--of:o--df:f--do";
-	opt = getopt32(argv, "do:fr", &opt_o);
+	opt_complementary = "?2:d--ofar:a--ofr";
+	opt = getopt32(argv, "do:far", &opt_o);
 	argv += optind;
 
-	if (opt == OPT_o)
-		offset = xatoull(opt_o);
+	/* LOOPDEV */
+	if (!opt && argv[0] && !argv[1]) {
+		char *s;
 
+		s = query_loop(argv[0]);
+		if (!s)
+			bb_simple_perror_msg_and_die(argv[0]);
+		printf("%s: %s\n", argv[0], s);
+		if (ENABLE_FEATURE_CLEAN_UP)
+			free(s);
+		return EXIT_SUCCESS;
+	}
+
+	/* -d LOOPDEV */
 	if (opt == OPT_d) {
-		/* -d BLOCKDEV */
-		if (!argv[0] || argv[1])
-			bb_show_usage();
 		if (del_loop(argv[0]))
 			bb_simple_perror_msg_and_die(argv[0]);
 		return EXIT_SUCCESS;
 	}
 
-	if (argv[0]) {
-		char *s;
-
-		if (opt == OPT_f) /* -f should not have arguments */
-			bb_show_usage();
+	/* -a */
+	if (opt == OPT_a) {
+		int n;
+		for (n = 0; n < 10; n++) {
+			char *s;
 
-		if (argv[1]) {
-			/* [-r] [-o OFS] BLOCKDEV FILE */
-			if (set_loop(&argv[0], argv[1], offset, (opt / OPT_r)) < 0)
-				bb_simple_perror_msg_and_die(argv[0]);
-			return EXIT_SUCCESS;
+			sprintf(dev, LOOP_FORMAT, n);
+			s = query_loop(dev);
+			if (s) {
+				printf("%s: %s\n", dev, s);
+				if (ENABLE_FEATURE_CLEAN_UP)
+					free(s);
+			}
 		}
-		/* [-r] [-o OFS] BLOCKDEV */
-		s = query_loop(argv[0]);
-		if (!s)
-			bb_simple_perror_msg_and_die(argv[0]);
-		printf("%s: %s\n", argv[0], s);
-		if (ENABLE_FEATURE_CLEAN_UP)
-			free(s);
 		return EXIT_SUCCESS;
 	}
 
-	/* [-r] [-o OFS|-f] with no params */
-	n = 0;
-	while (1) {
+	/* contains -f */
+	if (opt & OPT_f) {
 		char *s;
-		char dev[LOOP_NAMESIZE];
+		int n = 0;
 
-		sprintf(dev, LOOP_FORMAT, n);
-		s = query_loop(dev);
-		n++;
-		if (!s) {
-			if (n > 9 && errno && errno != ENXIO)
-				return EXIT_SUCCESS;
-			if (opt == OPT_f) {
-				puts(dev);
-				return EXIT_SUCCESS;
-			}
-		} else {
-			if (opt != OPT_f)
-				printf("%s: %s\n", dev, s);
-			if (ENABLE_FEATURE_CLEAN_UP)
+		do {
+			sprintf(dev, LOOP_FORMAT, n);
+			s = query_loop(dev);
+			if (s && ENABLE_FEATURE_CLEAN_UP)
 				free(s);
+		} while (s);
+		if ((opt == OPT_f) && !argv[0]) {
+			puts(dev);
+			return EXIT_SUCCESS;
 		}
 	}
-	return EXIT_SUCCESS;
+
+	/* [-r] [-o OFS] {-f|LOOPDEV} FILE */
+	if (argv[0] && ((opt & OPT_f) || argv[1])) {
+		unsigned long long offset = 0;
+		char *d = dev;
+
+		if (opt == OPT_o)
+			offset = xatoull(opt_o);
+		if (opt != OPT_f)
+			d = *(argv++);
+
+		if (argv[0]) {
+			if (set_loop(&d, argv[0], offset, (opt / OPT_r)) < 0)
+				bb_simple_perror_msg_and_die(argv[0]);
+			return EXIT_SUCCESS;
+		}
+	}
+
+	bb_show_usage();
+	return EXIT_FAILURE;
 }