dd: code shrink

[oweals/busybox.git] / util-linux / losetup.c

diff --git a/util-linux/losetup.c b/util-linux/losetup.c
index 6b9a810f283bc338b1f70178db36c9a34b41ca6d..d450b5a7825c3e8568093c3becd129c6be41b29b 100644 (file)
--- a/util-linux/losetup.c
+++ b/util-linux/losetup.c
@@ -4,61 +4,123 @@
  *
  * 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.
  */
 
-#include <getopt.h>
-#include <stdlib.h>
+//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 "busybox.h"
+#include "libbb.h"
 
-int losetup_main(int argc, char **argv)
+/* 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 UNUSED_PARAM, char **argv)
 {
-       unsigned long opt;
+       unsigned opt;
        char *opt_o;
-       int 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 */
+       };
 
-       opt = bb_getopt_ulflags(argc, argv, "do:", &opt_o);
-       argc -= optind;
+       opt_complementary = "?2:d--ofar:a--ofr";
+       opt = getopt32(argv, "do:far", &opt_o);
        argv += optind;
 
-       if (opt == 0x3) // -d + -o (illegal)
-               bb_show_usage();
+       /* LOOPDEV */
+       if (!opt && argv[0] && !argv[1]) {
+               char *s;
 
-       if (opt == 0x1) { // -d
-               /* detach takes exactly one argument */
-               if (argc != 1)
-                       bb_show_usage();
-               if (!del_loop(argv[0]))
-                       return EXIT_SUCCESS;
-               bb_perror_nomsg_and_die();
+               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;
        }
 
-       if (opt == 0x2) // -o
-               offset = bb_xparse_number(opt_o, NULL);
-
-       /* -o or no option */
+       /* -d LOOPDEV */
+       if (opt == OPT_d && argv[0]) {
+               if (del_loop(argv[0]))
+                       bb_simple_perror_msg_and_die(argv[0]);
+               return EXIT_SUCCESS;
+       }
 
-       if (argc == 2) {
-               if (set_loop(&argv[0], argv[1], offset) < 0)
-                       bb_perror_nomsg_and_die();
-       } else if (argc == 1) {
-               char *s = query_loop(argv[0]);
-               if (!s) bb_perror_nomsg_and_die();
-               printf("%s: %s\n", argv[0], s);
-               if (ENABLE_FEATURE_CLEAN_UP) free(s);
-       } else {
-               char dev[11] = "/dev/loop0";
-               char c;
-               for (c = '0'; c <= '9'; ++c) {
+       /* -a */
+       if (opt == OPT_a) {
+               int n;
+               for (n = 0; n < MAX_LOOP_NUM; n++) {
                        char *s;
-                       dev[9] = c;
+
+                       sprintf(dev, LOOP_FORMAT, n);
                        s = query_loop(dev);
                        if (s) {
                                printf("%s: %s\n", dev, s);
-                               if (ENABLE_FEATURE_CLEAN_UP) free(s);
+                               free(s);
                        }
                }
+               return EXIT_SUCCESS;
+       }
+
+       /* 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;
+               }
+       }
+
+       /* [-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;
+               }
        }
-       return EXIT_SUCCESS;
+
+       bb_show_usage(); /* does not return */
+       /*return EXIT_FAILURE;*/
 }