losetup: support /dev/loop10 and higher. closes bug 1627

function                                             old     new   delta
query_loop                                            91      95      +4
losetup_main                                         288     285      -3

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 34 insertions, 25 deletions

diff --git a/util-linux/losetup.c b/util-linux/losetup.c
index e224a4d54..e44773a07 100644
--- a/util-linux/losetup.c
+++ b/util-linux/losetup.c
@@ -10,44 +10,48 @@
 #include "libbb.h"
 
 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;
+        int n;
         char *opt_o;
-        char *s;
         unsigned long long offset = 0;
+        enum {
+                OPT_d = (1 << 0),
+                OPT_o = (1 << 1),
+                OPT_f = (1 << 2),
+        };
 
         /* max 2 args, all opts are mutually exclusive */
         opt_complementary = "?2:d--of:o--df:f-do";
         opt = getopt32(argv, "do:f", &opt_o);
-        argc -= optind;
         argv += optind;
 
-        if (opt == 0x2) // -o
+        if (opt == OPT_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)
+        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 (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;
-        }
+        if (argv[0]) {
+                char *s;
+
+                if (opt == OPT_f) /* -f should not have arguments */
+                        bb_show_usage();
 
-        if (argc == 1) {
-                /* -o or no option */
+                if (argv[1]) {
+                        /* [-o OFS] BLOCKDEV FILE */
+                        if (set_loop(&argv[0], argv[1], offset) < 0)
+                                bb_simple_perror_msg_and_die(argv[0]);
+                        return EXIT_SUCCESS;
+                }
+                /* [-o OFS] BLOCKDEV */
                 s = query_loop(argv[0]);
                 if (!s)
                         bb_simple_perror_msg_and_die(argv[0]);
@@ -57,23 +61,28 @@ int losetup_main(int argc, char **argv)
                 return EXIT_SUCCESS;
         }
 
-        /* -o, -f or no option */
+        /* [-o OFS|-f] with no params */
+        n = 0;
         while (1) {
+                char *s;
+                char dev[sizeof(LOOP_NAME) + sizeof(int)*3];
+
+                sprintf(dev, LOOP_NAME"%u", n);
                 s = query_loop(dev);
+                n++;
                 if (!s) {
-                        if (opt == 0x4) {
+                        if (n > 9 && errno && errno != ENXIO)
+                                return EXIT_SUCCESS;
+                        if (opt == OPT_f) {
                                 puts(dev);
                                 return EXIT_SUCCESS;
                         }
                 } else {
-                        if (opt != 0x4)
+                        if (opt != OPT_f)
                                 printf("%s: %s\n", dev, s);
                         if (ENABLE_FEATURE_CLEAN_UP)
                                 free(s);
                 }
-
-                if (++dev[sizeof(dev) - 2] > '9')
-                        break;
         }
         return EXIT_SUCCESS;
 }