commands/umount/umount.c

   1 /* umount - unmount a file system               Author: Andy Tanenbaum */
   2
   3 #define _MINIX 1                /* for proto of the non-POSIX umount() */
   4 #define _POSIX_SOURCE 1         /* for PATH_MAX from limits.h */
   5
   6 #include <minix/type.h>
   7 #include <sys/types.h>
   8 #include <sys/stat.h>
   9 #include <fcntl.h>
  10 #include <getopt.h>
  11 #include <errno.h>
  12 #include <limits.h>
  13 #include <minix/minlib.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16 #include <unistd.h>
  17 #include <sys/mount.h>
  18 #include <stdio.h>
  19
  20 int main(int argc, char **argv);
  21 int find_mtab_entry(char *name);
  22 void update_mtab(void);
  23 void usage(void);
  24
  25 static char device[PATH_MAX], mount_point[PATH_MAX], type[MNTNAMELEN],
  26                 flags[MNTFLAGLEN];
  27
  28 int main(argc, argv)
  29 int argc;
  30 char *argv[];
  31 {
  32   int found;
  33   int umount_flags = 0UL;
  34   int c;
  35   char *name;
  36
  37   while ((c = getopt (argc, argv, "e")) != -1)
  38   {
  39         switch (c) {
  40                 case 'e': umount_flags |= MS_EXISTING; break;
  41                 default: break;
  42         }
  43   }
  44
  45   if (argc - optind != 1) {
  46            usage();
  47   }
  48
  49   name = argv[optind];
  50
  51   found = find_mtab_entry(name);
  52
  53   if (umount2(name, umount_flags) < 0) {
  54         if (errno == EINVAL)
  55                 std_err("umount: Device not mounted\n");
  56         else if (errno == ENOTBLK)
  57                 std_err("umount: Not a mountpoint\n");
  58         else
  59                 perror("umount");
  60         exit(1);
  61   }
  62   if (found) {
  63         printf("%s unmounted from %s\n", device, mount_point);
  64   }
  65   return(0);
  66 }
  67
  68 int find_mtab_entry(name)
  69 char *name;
  70 {
  71 /* Find a matching mtab entry for 'name' which may be a special or a path,
  72  * and generate a new mtab file without this entry on the fly. Do not write
  73  * out the result yet. Return whether we found a matching entry.
  74  */
  75   char e_dev[PATH_MAX], e_mount_point[PATH_MAX], e_type[MNTNAMELEN],
  76         e_flags[MNTFLAGLEN];
  77   struct stat nstat, mstat;
  78   int n, found;
  79
  80   if (load_mtab("umount") < 0) return 0;
  81
  82   if (stat(name, &nstat) != 0) return 0;
  83
  84   found = 0;
  85   while (1) {
  86         n = get_mtab_entry(e_dev, e_mount_point, e_type, e_flags);
  87         if (n < 0) break;
  88         if (strcmp(name, e_dev) == 0 || (stat(e_mount_point, &mstat) == 0 &&
  89                 mstat.st_dev == nstat.st_dev && mstat.st_ino == nstat.st_ino))
  90         {
  91                 strlcpy(device, e_dev, PATH_MAX);
  92                 strlcpy(mount_point, e_mount_point, PATH_MAX);
  93                 strlcpy(type, e_type, MNTNAMELEN);
  94                 strlcpy(flags, e_flags, MNTFLAGLEN);
  95                 found = 1;
  96                 break;
  97         }
  98   }
  99
 100   return found;
 101 }
 102
 103 void usage()
 104 {
 105   std_err("Usage: umount [-e] name\n");
 106   exit(1);
 107 }