mount-setup.c

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU General Public License as published by
  10   the Free Software Foundation; either version 2 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <sys/mount.h>
  23 #include <errno.h>
  24 #include <sys/stat.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <libgen.h>
  28 #include <assert.h>
  29
  30 #include "mount-setup.h"
  31 #include "log.h"
  32
  33 enum {
  34         MOUNT_WHAT,
  35         MOUNT_WHERE,
  36         MOUNT_TYPE,
  37         MOUNT_OPTIONS,
  38         MOUNT_SKIP
  39 };
  40
  41 static const char *table[] = {
  42         "proc",    "/proc",             "proc",     NULL,
  43         "sysfs",   "/sys",              "sysfs",    NULL,
  44         "devtmps", "/dev",              "devtmpfs", "mode=755",
  45         "tmpfs",   "/dev/shm",          "tmpfs",    "mode=1777",
  46         "devpts",  "/dev/pts",          "devpts",   NULL,
  47         "cgroup",  "/cgroup/debug",     "cgroup",   "debug",
  48         "debugfs", "/sys/kernel/debug", "debugfs",  NULL,
  49         NULL
  50 };
  51
  52 static int is_mount_point(const char *t) {
  53         struct stat a, b;
  54         char *copy;
  55
  56         if (lstat(t, &a) < 0) {
  57
  58                 if (errno == ENOENT)
  59                         return 0;
  60
  61                 return -errno;
  62         }
  63
  64         if (!(copy = strdup(t)))
  65                 return -ENOMEM;
  66
  67         if (lstat(dirname(copy), &b) < 0) {
  68                 free(copy);
  69                 return -errno;
  70         }
  71
  72         free(copy);
  73
  74         return a.st_dev != b.st_dev;
  75
  76 }
  77
  78 static int mount_one(const char *t[]) {
  79         int r;
  80
  81         assert(t);
  82
  83         if ((r = is_mount_point(t[MOUNT_WHERE])) < 0)
  84                 return r;
  85
  86         if (r > 0)
  87                 return 0;
  88
  89         /* The access mode here doesn't really matter too much, since
  90          * the mounted file system will take precedence anyway. */
  91         mkdir(t[MOUNT_WHERE], 0755);
  92
  93         log_debug("Mounting %s to %s of type %s with options %s.",
  94                   t[MOUNT_WHAT],
  95                   t[MOUNT_WHERE],
  96                   t[MOUNT_TYPE],
  97                   t[MOUNT_OPTIONS]);
  98
  99         if (mount(t[MOUNT_WHAT],
 100                   t[MOUNT_WHERE],
 101                   t[MOUNT_TYPE],
 102                   0,
 103                   t[MOUNT_OPTIONS]) < 0) {
 104                 log_error("Failed to mount %s: %s", t[MOUNT_WHERE], strerror(errno));
 105                 return -errno;
 106         }
 107
 108         return 0;
 109 }
 110
 111 int mount_setup(void) {
 112         int r;
 113         const char **t;
 114
 115         for (t = table; *t; t += MOUNT_SKIP)
 116                 if ((r = mount_one(t)) < 0)
 117                         return r;
 118
 119         return 0;
 120 }