fs/aufs/sysaufs.c

   1 /*
   2  * Copyright (C) 2005-2017 Junjiro R. Okajima
   3  *
   4  * This program, aufs is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 /*
  19  * sysfs interface and lifetime management
  20  * they are necessary regardless sysfs is disabled.
  21  */
  22
  23 #include <linux/random.h>
  24 #include "aufs.h"
  25
  26 unsigned long sysaufs_si_mask;
  27 struct kset *sysaufs_kset;
  28
  29 #define AuSiAttr(_name) { \
  30         .attr   = { .name = __stringify(_name), .mode = 0444 }, \
  31         .show   = sysaufs_si_##_name,                           \
  32 }
  33
  34 static struct sysaufs_si_attr sysaufs_si_attr_xi_path = AuSiAttr(xi_path);
  35 struct attribute *sysaufs_si_attrs[] = {
  36         &sysaufs_si_attr_xi_path.attr,
  37         NULL,
  38 };
  39
  40 static const struct sysfs_ops au_sbi_ops = {
  41         .show   = sysaufs_si_show
  42 };
  43
  44 static struct kobj_type au_sbi_ktype = {
  45         .release        = au_si_free,
  46         .sysfs_ops      = &au_sbi_ops,
  47         .default_attrs  = sysaufs_si_attrs
  48 };
  49
  50 /* ---------------------------------------------------------------------- */
  51
  52 int sysaufs_si_init(struct au_sbinfo *sbinfo)
  53 {
  54         int err;
  55
  56         sbinfo->si_kobj.kset = sysaufs_kset;
  57         /* cf. sysaufs_name() */
  58         err = kobject_init_and_add
  59                 (&sbinfo->si_kobj, &au_sbi_ktype, /*&sysaufs_kset->kobj*/NULL,
  60                  SysaufsSiNamePrefix "%lx", sysaufs_si_id(sbinfo));
  61
  62         dbgaufs_si_null(sbinfo);
  63         if (!err) {
  64                 err = dbgaufs_si_init(sbinfo);
  65                 if (unlikely(err))
  66                         kobject_put(&sbinfo->si_kobj);
  67         }
  68         return err;
  69 }
  70
  71 void sysaufs_fin(void)
  72 {
  73         dbgaufs_fin();
  74         sysfs_remove_group(&sysaufs_kset->kobj, sysaufs_attr_group);
  75         kset_unregister(sysaufs_kset);
  76 }
  77
  78 int __init sysaufs_init(void)
  79 {
  80         int err;
  81
  82         do {
  83                 get_random_bytes(&sysaufs_si_mask, sizeof(sysaufs_si_mask));
  84         } while (!sysaufs_si_mask);
  85
  86         err = -EINVAL;
  87         sysaufs_kset = kset_create_and_add(AUFS_NAME, NULL, fs_kobj);
  88         if (unlikely(!sysaufs_kset))
  89                 goto out;
  90         err = PTR_ERR(sysaufs_kset);
  91         if (IS_ERR(sysaufs_kset))
  92                 goto out;
  93         err = sysfs_create_group(&sysaufs_kset->kobj, sysaufs_attr_group);
  94         if (unlikely(err)) {
  95                 kset_unregister(sysaufs_kset);
  96                 goto out;
  97         }
  98
  99         err = dbgaufs_init();
 100         if (unlikely(err))
 101                 sysaufs_fin();
 102 out:
 103         return err;
 104 }