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 21108d0bf..c69763335 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;
 }