X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=util-linux%2Flosetup.c;h=d450b5a7825c3e8568093c3becd129c6be41b29b;hb=066e76befe5d39fc3451846af94cbba96747186c;hp=62a1a7363fbb8cdfffb39b56b76abd9207edc21c;hpb=c93b162248892265eae5f54e9ee409074dfa08c5;p=oweals%2Fbusybox.git

diff --git a/util-linux/losetup.c b/util-linux/losetup.c
index 62a1a7363..d450b5a78 100644
--- a/util-linux/losetup.c
+++ b/util-linux/losetup.c
@@ -4,50 +4,55 @@
  *
  * Copyright (C) 2002  Matt Kraai.
  *
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 
+//usage:#define losetup_trivial_usage
+//usage:       "[-r] [-o OFS] {-f|LOOPDEV} FILE - associate loop devices\n"
+//usage:       "	losetup -d LOOPDEV - disassociate\n"
+//usage:       "	losetup -a - show status\n"
+//usage:       "	losetup -f - show next free loop device"
+//usage:#define losetup_full_usage "\n\n"
+//usage:       "	-o OFS	Start OFS bytes into FILE"
+//usage:     "\n	-r	Read-only"
+//usage:     "\n	-f	Show/use next free loop device"
+//usage:
+//usage:#define losetup_notes_usage
+//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"
+//usage:       "Two arguments (losetup /dev/loop1 file.img) create a new association,\n"
+//usage:       "with an optional offset (-o 12345). Encryption is not yet supported.\n"
+//usage:       "losetup -f will show the first loop free loop device\n\n"
+
 #include "libbb.h"
 
+/* 1048575 is a max possible minor number in Linux circa 2010 */
+/* for now use something less extreme */
+#define MAX_LOOP_NUM 1023
+
 int losetup_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int losetup_main(int argc, char **argv)
+int losetup_main(int argc UNUSED_PARAM, char **argv)
 {
-	char dev[] = LOOP_NAME"0";
 	unsigned opt;
 	char *opt_o;
-	char *s;
-	unsigned long long offset = 0;
+	char dev[LOOP_NAMESIZE];
+	enum {
+		OPT_d = (1 << 0),
+		OPT_o = (1 << 1),
+		OPT_f = (1 << 2),
+		OPT_a = (1 << 3),
+		OPT_r = (1 << 4), /* must be last */
+	};
 
-	/* max 2 args, all opts are mutially exclusive */
-	opt_complementary = "?2:d--of:o--df:f-do";
-	opt = getopt32(argv, "do:f", &opt_o);
-	argc -= optind;
+	opt_complementary = "?2:d--ofar:a--ofr";
+	opt = getopt32(argv, "do:far", &opt_o);
 	argv += optind;
 
-	if (opt == 0x2) // -o
-		offset = xatoull(opt_o);
-
-	if (opt == 0x4 && argc) // -f does not take any argument
-		bb_show_usage();
-
-	if (opt == 0x1) { // -d
-		/* detach takes exactly one argument */
-		if (argc != 1)
-			bb_show_usage();
-		if (del_loop(argv[0]))
-			bb_simple_perror_msg_and_die(argv[0]);
-		return EXIT_SUCCESS;
-	}
-
-	if (argc == 2) {
-		/* -o or no option */
-		if (set_loop(&argv[0], argv[1], offset) < 0)
-			bb_simple_perror_msg_and_die(argv[0]);
-		return EXIT_SUCCESS;
-	}
+	/* LOOPDEV */
+	if (!opt && argv[0] && !argv[1]) {
+		char *s;
 
-	if (argc == 1) {
-		/* -o or no option */
 		s = query_loop(argv[0]);
 		if (!s)
 			bb_simple_perror_msg_and_die(argv[0]);
@@ -57,23 +62,65 @@ int losetup_main(int argc, char **argv)
 		return EXIT_SUCCESS;
 	}
 
-	/* -o, -f or no option */
-	while (1) {
-		s = query_loop(dev);
-		if (!s) {
-			if (opt == 0x4) {
-				puts(dev);
-				return EXIT_SUCCESS;
-			}
-		} else {
-			if (opt != 0x4)
+	/* -d LOOPDEV */
+	if (opt == OPT_d && argv[0]) {
+		if (del_loop(argv[0]))
+			bb_simple_perror_msg_and_die(argv[0]);
+		return EXIT_SUCCESS;
+	}
+
+	/* -a */
+	if (opt == OPT_a) {
+		int n;
+		for (n = 0; n < MAX_LOOP_NUM; n++) {
+			char *s;
+
+			sprintf(dev, LOOP_FORMAT, n);
+			s = query_loop(dev);
+			if (s) {
 				printf("%s: %s\n", dev, s);
-			if (ENABLE_FEATURE_CLEAN_UP)
 				free(s);
+			}
 		}
+		return EXIT_SUCCESS;
+	}
 
-		if (++dev[sizeof(dev) - 2] > '9')
-			break;
+	/* contains -f */
+	if (opt & OPT_f) {
+		char *s;
+		int n = 0;
+
+		do {
+			if (n > MAX_LOOP_NUM)
+				bb_error_msg_and_die("no free loop devices");
+			sprintf(dev, LOOP_FORMAT, n++);
+			s = query_loop(dev);
+			free(s);
+		} while (s);
+		/* now: dev is next free "/dev/loopN" */
+		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(); /* does not return */
+	/*return EXIT_FAILURE;*/
 }