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>

diff --git a/util-linux/losetup.c b/util-linux/losetup.c
index 21108d0bfb372fced9e0925ebd1a0037b12c21d4..c69763335c166f68fe59880345d100492c7c4e2f 100644 (file)
--- 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;
 }