libbb/mtab.c

   1 /* vi: set sw=4 ts=4: */
   2 #include <stdlib.h>
   3 #include <unistd.h>
   4 #include <errno.h>
   5 #include <string.h>
   6 #include <stdio.h>
   7 #include <mntent.h>
   8 #include "libbb.h"
   9
  10 extern const char mtab_file[];  /* Defined in utility.c */
  11 static const int MS_RDONLY = 1; /* Mount read-only.  */
  12
  13 void erase_mtab(const char *name)
  14 {
  15         struct mntent entries[20];
  16         int count = 0;
  17         FILE *mountTable = setmntent(mtab_file, "r");
  18         struct mntent *m;
  19
  20         /* Check if reading the mtab file failed */
  21         if (mountTable == 0
  22                         /* Bummer.  fall back on trying the /proc filesystem */
  23                         && (mountTable = setmntent("/proc/mounts", "r")) == 0) {
  24                 perror_msg("%s", mtab_file);
  25                 return;
  26         }
  27
  28         while ((m = getmntent(mountTable)) != 0) {
  29                 entries[count].mnt_fsname = strdup(m->mnt_fsname);
  30                 entries[count].mnt_dir = strdup(m->mnt_dir);
  31                 entries[count].mnt_type = strdup(m->mnt_type);
  32                 entries[count].mnt_opts = strdup(m->mnt_opts);
  33                 entries[count].mnt_freq = m->mnt_freq;
  34                 entries[count].mnt_passno = m->mnt_passno;
  35                 count++;
  36         }
  37         endmntent(mountTable);
  38         if ((mountTable = setmntent(mtab_file, "w"))) {
  39                 int i;
  40
  41                 for (i = 0; i < count; i++) {
  42                         int result = (strcmp(entries[i].mnt_fsname, name) == 0
  43                                                   || strcmp(entries[i].mnt_dir, name) == 0);
  44
  45                         if (result)
  46                                 continue;
  47                         else
  48                                 addmntent(mountTable, &entries[i]);
  49                 }
  50                 endmntent(mountTable);
  51         } else if (errno != EROFS)
  52                 perror_msg("%s", mtab_file);
  53 }
  54
  55 void write_mtab(char *blockDevice, char *directory,
  56                                 char *filesystemType, long flags, char *string_flags)
  57 {
  58         FILE *mountTable = setmntent(mtab_file, "a+");
  59         struct mntent m;
  60
  61         if (mountTable == 0) {
  62                 perror_msg("%s", mtab_file);
  63                 return;
  64         }
  65         if (mountTable) {
  66                 int length = strlen(directory);
  67
  68                 if (length > 1 && directory[length - 1] == '/')
  69                         directory[length - 1] = '\0';
  70
  71                 if (filesystemType == 0) {
  72                         struct mntent *p = find_mount_point(blockDevice, "/proc/mounts");
  73
  74                         if (p && p->mnt_type)
  75                                 filesystemType = p->mnt_type;
  76                 }
  77                 m.mnt_fsname = blockDevice;
  78                 m.mnt_dir = directory;
  79                 m.mnt_type = filesystemType ? filesystemType : "default";
  80
  81                 if (*string_flags) {
  82                         m.mnt_opts = string_flags;
  83                 } else {
  84                         if ((flags | MS_RDONLY) == flags)
  85                                 m.mnt_opts = "ro";
  86                         else
  87                                 m.mnt_opts = "rw";
  88                 }
  89
  90                 m.mnt_freq = 0;
  91                 m.mnt_passno = 0;
  92                 addmntent(mountTable, &m);
  93                 endmntent(mountTable);
  94         }
  95 }