bc: convert to "G trick" - this returns bc to zero bss increase

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

diff --git a/util-linux/losetup.c b/util-linux/losetup.c
index c69763335c166f68fe59880345d100492c7c4e2f..6b171d7102d068e927903398c4a8b125f1eb16b5 100644 (file)
--- a/util-linux/losetup.c
+++ b/util-linux/losetup.c
@@ -6,16 +6,28 @@
  *
  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
+//config:config LOSETUP
+//config:      bool "losetup (5.4 kb)"
+//config:      default y
+//config:      select PLATFORM_LINUX
+//config:      help
+//config:      losetup is used to associate or detach a loop device with a regular
+//config:      file or block device, and to query the status of a loop device. This
+//config:      version does not currently support enabling data encryption.
+
+//applet:IF_LOSETUP(APPLET_NOEXEC(losetup, losetup, BB_DIR_SBIN, BB_SUID_DROP, losetup))
+
+//kbuild:lib-$(CONFIG_LOSETUP) += losetup.o
 
 //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 of  all\n"
-//usage:       "       losetup -f - show next available"
+//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/find first free loop device"
+//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"
@@ -27,6 +39,10 @@
 
 #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 UNUSED_PARAM, char **argv)
 {
@@ -41,8 +57,7 @@ int losetup_main(int argc UNUSED_PARAM, char **argv)
                OPT_r = (1 << 4), /* must be last */
        };
 
-       opt_complementary = "?2:d--ofar:a--ofr";
-       opt = getopt32(argv, "do:far", &opt_o);
+       opt = getopt32(argv, "^" "do:far" "\0" "?2:d--ofar:a--ofr", &opt_o);
        argv += optind;
 
        /* LOOPDEV */
@@ -59,7 +74,7 @@ int losetup_main(int argc UNUSED_PARAM, char **argv)
        }
 
        /* -d LOOPDEV */
-       if (opt == OPT_d) {
+       if (opt == OPT_d && argv[0]) {
                if (del_loop(argv[0]))
                        bb_simple_perror_msg_and_die(argv[0]);
                return EXIT_SUCCESS;
@@ -68,15 +83,14 @@ int losetup_main(int argc UNUSED_PARAM, char **argv)
        /* -a */
        if (opt == OPT_a) {
                int n;
-               for (n = 0; n < 10; 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);
+                               free(s);
                        }
                }
                return EXIT_SUCCESS;
@@ -88,11 +102,13 @@ int losetup_main(int argc UNUSED_PARAM, char **argv)
                int n = 0;
 
                do {
-                       sprintf(dev, LOOP_FORMAT, n);
+                       if (n > MAX_LOOP_NUM)
+                               bb_error_msg_and_die("no free loop devices");
+                       sprintf(dev, LOOP_FORMAT, n++);
                        s = query_loop(dev);
-                       if (s && ENABLE_FEATURE_CLEAN_UP)
-                               free(s);
+                       free(s);
                } while (s);
+               /* now: dev is next free "/dev/loopN" */
                if ((opt == OPT_f) && !argv[0]) {
                        puts(dev);
                        return EXIT_SUCCESS;
@@ -104,18 +120,43 @@ int losetup_main(int argc UNUSED_PARAM, char **argv)
                unsigned long long offset = 0;
                char *d = dev;
 
-               if (opt == OPT_o)
+               if (opt & OPT_o)
                        offset = xatoull(opt_o);
-               if (opt != OPT_f)
-                       d = *(argv++);
+               if (!(opt & OPT_f))
+                       d = *argv++;
 
                if (argv[0]) {
-                       if (set_loop(&d, argv[0], offset, (opt / OPT_r)) < 0)
+                       if (set_loop(&d, argv[0], offset, (opt & OPT_r) ? BB_LO_FLAGS_READ_ONLY : 0) < 0)
                                bb_simple_perror_msg_and_die(argv[0]);
                        return EXIT_SUCCESS;
                }
        }
 
-       bb_show_usage();
-       return EXIT_FAILURE;
+       /* TODO: util-linux 2.28 shows this when run w/o params:
+        * NAME       SIZELIMIT OFFSET AUTOCLEAR RO BACK-FILE     DIO
+        * /dev/loop0         0      0         1  0 /PATH/TO/FILE   0
+        *
+        * implemented by reading /sys:
+        *
+        * open("/sys/block", O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = 3
+        * newfstatat(3, "loop0/loop/backing_file", {st_mode=S_IFREG|0444, st_size=4096, ...}, 0) = 0
+        * stat("/dev/loop0", {st_mode=S_IFBLK|0660, st_rdev=makedev(7, 0), ...}) = 0
+        * open("/sys/dev/block/7:0/loop/offset", O_RDONLY|O_CLOEXEC) = 5
+        * read(5, "0\n", 4096)                    = 2
+        * open("/sys/dev/block/7:0/loop/sizelimit", O_RDONLY|O_CLOEXEC) = 5
+        * read(5, "0\n", 4096)                    = 2
+        * open("/sys/dev/block/7:0/loop/offset", O_RDONLY|O_CLOEXEC) = 5
+        * read(5, "0\n", 4096)                    = 2
+        * open("/sys/dev/block/7:0/loop/autoclear", O_RDONLY|O_CLOEXEC) = 5
+        * read(5, "1\n", 4096)                    = 2
+        * open("/sys/dev/block/7:0/ro", O_RDONLY|O_CLOEXEC)     = 5
+        * read(5, "0\n", 4096)                    = 2
+        * open("/sys/dev/block/7:0/loop/backing_file", O_RDONLY|O_CLOEXEC) = 5
+        * read(5, "/PATH/TO/FILE", 4096) = 37
+        * open("/sys/dev/block/7:0/loop/dio", O_RDONLY|O_CLOEXEC) = 5
+        * read(5, "0\n", 4096)                    = 2
+        */
+
+       bb_show_usage(); /* does not return */
+       /*return EXIT_FAILURE;*/
 }