linux/fs/statfs.c
<<
>>
Prefs
   1#include <linux/syscalls.h>
   2#include <linux/export.h>
   3#include <linux/fs.h>
   4#include <linux/file.h>
   5#include <linux/mount.h>
   6#include <linux/namei.h>
   7#include <linux/statfs.h>
   8#include <linux/security.h>
   9#include <linux/uaccess.h>
  10#include "internal.h"
  11
  12static int flags_by_mnt(int mnt_flags)
  13{
  14        int flags = 0;
  15
  16        if (mnt_flags & MNT_READONLY)
  17                flags |= ST_RDONLY;
  18        if (mnt_flags & MNT_NOSUID)
  19                flags |= ST_NOSUID;
  20        if (mnt_flags & MNT_NODEV)
  21                flags |= ST_NODEV;
  22        if (mnt_flags & MNT_NOEXEC)
  23                flags |= ST_NOEXEC;
  24        if (mnt_flags & MNT_NOATIME)
  25                flags |= ST_NOATIME;
  26        if (mnt_flags & MNT_NODIRATIME)
  27                flags |= ST_NODIRATIME;
  28        if (mnt_flags & MNT_RELATIME)
  29                flags |= ST_RELATIME;
  30        return flags;
  31}
  32
  33static int flags_by_sb(int s_flags)
  34{
  35        int flags = 0;
  36        if (s_flags & MS_SYNCHRONOUS)
  37                flags |= ST_SYNCHRONOUS;
  38        if (s_flags & MS_MANDLOCK)
  39                flags |= ST_MANDLOCK;
  40        return flags;
  41}
  42
  43static int calculate_f_flags(struct vfsmount *mnt)
  44{
  45        return ST_VALID | flags_by_mnt(mnt->mnt_flags) |
  46                flags_by_sb(mnt->mnt_sb->s_flags);
  47}
  48
  49static int statfs_by_dentry(struct dentry *dentry, struct kstatfs *buf)
  50{
  51        int retval;
  52
  53        if (!dentry->d_sb->s_op->statfs)
  54                return -ENOSYS;
  55
  56        memset(buf, 0, sizeof(*buf));
  57        retval = security_sb_statfs(dentry);
  58        if (retval)
  59                return retval;
  60        retval = dentry->d_sb->s_op->statfs(dentry, buf);
  61        if (retval == 0 && buf->f_frsize == 0)
  62                buf->f_frsize = buf->f_bsize;
  63        return retval;
  64}
  65
  66int vfs_statfs(struct path *path, struct kstatfs *buf)
  67{
  68        int error;
  69
  70        error = statfs_by_dentry(path->dentry, buf);
  71        if (!error)
  72                buf->f_flags = calculate_f_flags(path->mnt);
  73        return error;
  74}
  75EXPORT_SYMBOL(vfs_statfs);
  76
  77int user_statfs(const char __user *pathname, struct kstatfs *st)
  78{
  79        struct path path;
  80        int error = user_path_at(AT_FDCWD, pathname, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path);
  81        if (!error) {
  82                error = vfs_statfs(&path, st);
  83                path_put(&path);
  84        }
  85        return error;
  86}
  87
  88int fd_statfs(int fd, struct kstatfs *st)
  89{
  90        int fput_needed;
  91        struct file *file = fget_light(fd, &fput_needed);
  92        int error = -EBADF;
  93        if (file) {
  94                error = vfs_statfs(&file->f_path, st);
  95                fput_light(file, fput_needed);
  96        }
  97        return error;
  98}
  99
 100static int do_statfs_native(struct kstatfs *st, struct statfs __user *p)
 101{
 102        struct statfs buf;
 103
 104        if (sizeof(buf) == sizeof(*st))
 105                memcpy(&buf, st, sizeof(*st));
 106        else {
 107                if (sizeof buf.f_blocks == 4) {
 108                        if ((st->f_blocks | st->f_bfree | st->f_bavail |
 109                             st->f_bsize | st->f_frsize) &
 110                            0xffffffff00000000ULL)
 111                                return -EOVERFLOW;
 112                        /*
 113                         * f_files and f_ffree may be -1; it's okay to stuff
 114                         * that into 32 bits
 115                         */
 116                        if (st->f_files != -1 &&
 117                            (st->f_files & 0xffffffff00000000ULL))
 118                                return -EOVERFLOW;
 119                        if (st->f_ffree != -1 &&
 120                            (st->f_ffree & 0xffffffff00000000ULL))
 121                                return -EOVERFLOW;
 122                }
 123
 124                buf.f_type = st->f_type;
 125                buf.f_bsize = st->f_bsize;
 126                buf.f_blocks = st->f_blocks;
 127                buf.f_bfree = st->f_bfree;
 128                buf.f_bavail = st->f_bavail;
 129                buf.f_files = st->f_files;
 130                buf.f_ffree = st->f_ffree;
 131                buf.f_fsid = st->f_fsid;
 132                buf.f_namelen = st->f_namelen;
 133                buf.f_frsize = st->f_frsize;
 134                buf.f_flags = st->f_flags;
 135                memset(buf.f_spare, 0, sizeof(buf.f_spare));
 136        }
 137        if (copy_to_user(p, &buf, sizeof(buf)))
 138                return -EFAULT;
 139        return 0;
 140}
 141
 142static int do_statfs64(struct kstatfs *st, struct statfs64 __user *p)
 143{
 144        struct statfs64 buf;
 145        if (sizeof(buf) == sizeof(*st))
 146                memcpy(&buf, st, sizeof(*st));
 147        else {
 148                buf.f_type = st->f_type;
 149                buf.f_bsize = st->f_bsize;
 150                buf.f_blocks = st->f_blocks;
 151                buf.f_bfree = st->f_bfree;
 152                buf.f_bavail = st->f_bavail;
 153                buf.f_files = st->f_files;
 154                buf.f_ffree = st->f_ffree;
 155                buf.f_fsid = st->f_fsid;
 156                buf.f_namelen = st->f_namelen;
 157                buf.f_frsize = st->f_frsize;
 158                buf.f_flags = st->f_flags;
 159                memset(buf.f_spare, 0, sizeof(buf.f_spare));
 160        }
 161        if (copy_to_user(p, &buf, sizeof(buf)))
 162                return -EFAULT;
 163        return 0;
 164}
 165
 166SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct statfs __user *, buf)
 167{
 168        struct kstatfs st;
 169        int error = user_statfs(pathname, &st);
 170        if (!error)
 171                error = do_statfs_native(&st, buf);
 172        return error;
 173}
 174
 175SYSCALL_DEFINE3(statfs64, const char __user *, pathname, size_t, sz, struct statfs64 __user *, buf)
 176{
 177        struct kstatfs st;
 178        int error;
 179        if (sz != sizeof(*buf))
 180                return -EINVAL;
 181        error = user_statfs(pathname, &st);
 182        if (!error)
 183                error = do_statfs64(&st, buf);
 184        return error;
 185}
 186
 187SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct statfs __user *, buf)
 188{
 189        struct kstatfs st;
 190        int error = fd_statfs(fd, &st);
 191        if (!error)
 192                error = do_statfs_native(&st, buf);
 193        return error;
 194}
 195
 196SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user *, buf)
 197{
 198        struct kstatfs st;
 199        int error;
 200
 201        if (sz != sizeof(*buf))
 202                return -EINVAL;
 203
 204        error = fd_statfs(fd, &st);
 205        if (!error)
 206                error = do_statfs64(&st, buf);
 207        return error;
 208}
 209
 210int vfs_ustat(dev_t dev, struct kstatfs *sbuf)
 211{
 212        struct super_block *s = user_get_super(dev);
 213        int err;
 214        if (!s)
 215                return -EINVAL;
 216
 217        err = statfs_by_dentry(s->s_root, sbuf);
 218        drop_super(s);
 219        return err;
 220}
 221
 222SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf)
 223{
 224        struct ustat tmp;
 225        struct kstatfs sbuf;
 226        int err = vfs_ustat(new_decode_dev(dev), &sbuf);
 227        if (err)
 228                return err;
 229
 230        memset(&tmp,0,sizeof(struct ustat));
 231        tmp.f_tfree = sbuf.f_bfree;
 232        tmp.f_tinode = sbuf.f_ffree;
 233
 234        return copy_to_user(ubuf, &tmp, sizeof(struct ustat)) ? -EFAULT : 0;
 235}
 236
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.