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;
  81        unsigned int lookup_flags = LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT;
  82retry:
  83        error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
  84        if (!error) {
  85                error = vfs_statfs(&path, st);
  86                path_put(&path);
  87                if (retry_estale(error, lookup_flags)) {
  88                        lookup_flags |= LOOKUP_REVAL;
  89                        goto retry;
  90                }
  91        }
  92        return error;
  93}
  94
  95int fd_statfs(int fd, struct kstatfs *st)
  96{
  97        struct fd f = fdget_raw(fd);
  98        int error = -EBADF;
  99        if (f.file) {
 100                error = vfs_statfs(&f.file->f_path, st);
 101                fdput(f);
 102        }
 103        return error;
 104}
 105
 106static int do_statfs_native(struct kstatfs *st, struct statfs __user *p)
 107{
 108        struct statfs buf;
 109
 110        if (sizeof(buf) == sizeof(*st))
 111                memcpy(&buf, st, sizeof(*st));
 112        else {
 113                if (sizeof buf.f_blocks == 4) {
 114                        if ((st->f_blocks | st->f_bfree | st->f_bavail |
 115                             st->f_bsize | st->f_frsize) &
 116                            0xffffffff00000000ULL)
 117                                return -EOVERFLOW;
 118                        /*
 119                         * f_files and f_ffree may be -1; it's okay to stuff
 120                         * that into 32 bits
 121                         */
 122                        if (st->f_files != -1 &&
 123                            (st->f_files & 0xffffffff00000000ULL))
 124                                return -EOVERFLOW;
 125                        if (st->f_ffree != -1 &&
 126                            (st->f_ffree & 0xffffffff00000000ULL))
 127                                return -EOVERFLOW;
 128                }
 129
 130                buf.f_type = st->f_type;
 131                buf.f_bsize = st->f_bsize;
 132                buf.f_blocks = st->f_blocks;
 133                buf.f_bfree = st->f_bfree;
 134                buf.f_bavail = st->f_bavail;
 135                buf.f_files = st->f_files;
 136                buf.f_ffree = st->f_ffree;
 137                buf.f_fsid = st->f_fsid;
 138                buf.f_namelen = st->f_namelen;
 139                buf.f_frsize = st->f_frsize;
 140                buf.f_flags = st->f_flags;
 141                memset(buf.f_spare, 0, sizeof(buf.f_spare));
 142        }
 143        if (copy_to_user(p, &buf, sizeof(buf)))
 144                return -EFAULT;
 145        return 0;
 146}
 147
 148static int do_statfs64(struct kstatfs *st, struct statfs64 __user *p)
 149{
 150        struct statfs64 buf;
 151        if (sizeof(buf) == sizeof(*st))
 152                memcpy(&buf, st, sizeof(*st));
 153        else {
 154                buf.f_type = st->f_type;
 155                buf.f_bsize = st->f_bsize;
 156                buf.f_blocks = st->f_blocks;
 157                buf.f_bfree = st->f_bfree;
 158                buf.f_bavail = st->f_bavail;
 159                buf.f_files = st->f_files;
 160                buf.f_ffree = st->f_ffree;
 161                buf.f_fsid = st->f_fsid;
 162                buf.f_namelen = st->f_namelen;
 163                buf.f_frsize = st->f_frsize;
 164                buf.f_flags = st->f_flags;
 165                memset(buf.f_spare, 0, sizeof(buf.f_spare));
 166        }
 167        if (copy_to_user(p, &buf, sizeof(buf)))
 168                return -EFAULT;
 169        return 0;
 170}
 171
 172SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct statfs __user *, buf)
 173{
 174        struct kstatfs st;
 175        int error = user_statfs(pathname, &st);
 176        if (!error)
 177                error = do_statfs_native(&st, buf);
 178        return error;
 179}
 180
 181SYSCALL_DEFINE3(statfs64, const char __user *, pathname, size_t, sz, struct statfs64 __user *, buf)
 182{
 183        struct kstatfs st;
 184        int error;
 185        if (sz != sizeof(*buf))
 186                return -EINVAL;
 187        error = user_statfs(pathname, &st);
 188        if (!error)
 189                error = do_statfs64(&st, buf);
 190        return error;
 191}
 192
 193SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct statfs __user *, buf)
 194{
 195        struct kstatfs st;
 196        int error = fd_statfs(fd, &st);
 197        if (!error)
 198                error = do_statfs_native(&st, buf);
 199        return error;
 200}
 201
 202SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user *, buf)
 203{
 204        struct kstatfs st;
 205        int error;
 206
 207        if (sz != sizeof(*buf))
 208                return -EINVAL;
 209
 210        error = fd_statfs(fd, &st);
 211        if (!error)
 212                error = do_statfs64(&st, buf);
 213        return error;
 214}
 215
 216int vfs_ustat(dev_t dev, struct kstatfs *sbuf)
 217{
 218        struct super_block *s = user_get_super(dev);
 219        int err;
 220        if (!s)
 221                return -EINVAL;
 222
 223        err = statfs_by_dentry(s->s_root, sbuf);
 224        drop_super(s);
 225        return err;
 226}
 227
 228SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf)
 229{
 230        struct ustat tmp;
 231        struct kstatfs sbuf;
 232        int err = vfs_ustat(new_decode_dev(dev), &sbuf);
 233        if (err)
 234                return err;
 235
 236        memset(&tmp,0,sizeof(struct ustat));
 237        tmp.f_tfree = sbuf.f_bfree;
 238        tmp.f_tinode = sbuf.f_ffree;
 239
 240        return copy_to_user(ubuf, &tmp, sizeof(struct ustat)) ? -EFAULT : 0;
 241}
 242
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.