losetup: add -a option to list all used loop devices

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/mount/lomount.c b/mount/lomount.c
index 000a7b814013c1d0a6aa7ad8ac604af1d18caa6a..da1d2e427d4553a3cac03bfe7b0cd50cc767d753 100644 (file)
--- a/mount/lomount.c
+++ b/mount/lomount.c
@@ -28,6 +28,8 @@ extern char *progname;
 extern char *xstrdup (const char *s);  /* not: #include "sundries.h" */
 extern void error (const char *fmt, ...);      /* idem */
 
+#define SIZE(a) (sizeof(a)/sizeof(a[0]))
+
 #ifdef LOOP_SET_FD
 
 static int
@@ -128,6 +130,41 @@ show_loop(char *device) {
        close (fd);
        return 1;
 }
+
+static int
+show_used_loop_devices (void) {
+       char dev[20];
+       char *loop_formats[] = { "/dev/loop%d", "/dev/loop/%d" };
+       int i, j, fd, permission = 0, somedev = 0;
+       struct stat statbuf;
+       struct loop_info loopinfo;
+
+       for (j = 0; j < SIZE(loop_formats); j++) {
+           for(i = 0; i < 256; i++) {
+               sprintf(dev, loop_formats[j], i);
+               if (stat (dev, &statbuf) == 0 && S_ISBLK(statbuf.st_mode)) {
+                       fd = open (dev, O_RDONLY);
+                       if (fd >= 0) {
+                               if(ioctl (fd, LOOP_GET_STATUS, &loopinfo) == 0)
+                                       show_loop(dev);
+                               close (fd);
+                               somedev++;
+                       } else if (errno == EACCES)
+                               permission++;
+                       continue; /* continue trying as long as devices exist */
+               }
+               break;
+           }
+       }
+
+       if (somedev==0 && permission) {
+               error(_("%s: no permission to look at /dev/loop#"), progname);
+               return 1;
+       }
+       return 0;
+}
+
+
 #endif
 
 int
@@ -139,8 +176,6 @@ is_loop_device (const char *device) {
                major(statbuf.st_rdev) == LOOPMAJOR);
 }
 
-#define SIZE(a) (sizeof(a)/sizeof(a[0]))
-
 char *
 find_unused_loop_device (void) {
        /* Just creating a device, say in /tmp, is probably a bad idea -
@@ -403,12 +438,13 @@ char *progname;
 
 static void
 usage(void) {
-       fprintf(stderr, _("usage:\n\
-  %s loop_device                                       # give info\n\
-  %s -d loop_device                                    # delete\n\
-  %s -f                                                # find unused\n\
-  %s [-e encryption] [-o offset] {-f|loop_device} file # setup\n"),
-               progname, progname, progname, progname);
+       fprintf(stderr, _("usage:\n"
+  "  %1$s loop_device                                       # give info\n"
+  "  %1$s -d loop_device                                    # delete\n"
+  "  %1$s -f                                                # find unused\n"
+  "  %1$s -a                                                # list all used\n"
+  "  %1$s [-e encryption] [-o offset] {-f|loop_device} file # setup\n"),
+               progname);
        exit(1);
 }
 
@@ -442,7 +478,7 @@ error (const char *fmt, ...) {
 int
 main(int argc, char **argv) {
        char *p, *offset, *encryption, *passfd, *device, *file;
-       int delete, find, c;
+       int delete, find, c, all;
        int res = 0;
        int ro = 0;
        int pfd = -1;
@@ -452,7 +488,7 @@ main(int argc, char **argv) {
        bindtextdomain(PACKAGE, LOCALEDIR);
        textdomain(PACKAGE);
 
-       delete = find = 0;
+       delete = find = all = 0;
        off = 0;
        offset = encryption = passfd = NULL;
 
@@ -460,8 +496,11 @@ main(int argc, char **argv) {
        if ((p = strrchr(progname, '/')) != NULL)
                progname = p+1;
 
-       while ((c = getopt(argc, argv, "de:E:fo:p:v")) != -1) {
+       while ((c = getopt(argc, argv, "ade:E:fo:p:v")) != -1) {
                switch (c) {
+               case 'a':
+                       all = 1;
+                       break;
                case 'd':
                        delete = 1;
                        break;
@@ -489,17 +528,22 @@ main(int argc, char **argv) {
        if (argc == 1) {
                usage();
        } else if (delete) {
-               if (argc != optind+1 || encryption || offset || find)
+               if (argc != optind+1 || encryption || offset || find || all)
                        usage();
        } else if (find) {
-               if (argc < optind || argc > optind+1)
+               if (all || argc < optind || argc > optind+1)
+                       usage();
+       } else if (all) {
+               if (argc > 2)
                        usage();
        } else {
                if (argc < optind+1 || argc > optind+2)
                        usage();
        }
 
-       if (find) {
+       if (all)
+               return show_used_loop_devices();
+       else if (find) {
                device = find_unused_loop_device();
                if (device == NULL)
                        return -1;

diff --git a/mount/losetup.8 b/mount/losetup.8
index 06022ef4e8ee4e128d25a7583ee55ce3219045bb..f2bb5c8321d0b8d14b3fafe983d343d3b76b94b7 100644 (file)
--- a/mount/losetup.8
+++ b/mount/losetup.8
@@ -9,6 +9,8 @@ Get info:
 .B losetup
 .I loop_device
 .sp
+.B losetup -a
+.sp
 .in -5
 Delete loop:
 .sp
@@ -66,6 +68,8 @@ option, or one uses a name with the
 .B \-e
 option.)
 .SH OPTIONS
+.IP \fB\-a\fP
+Show status of all loop devices.
 .IP \fB\-d\fP
 Detach the file or device associated with the specified loop device.
 .IP "\fB\-E \fIencryption_type\fP"