/usr/src/aufs-4.9+20161219/fs/aufs/rdu.c is in aufs-dkms 4.9+20161219-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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* Copyright (C) 2005-2016 Junjiro R. Okajima
*
* This program, aufs is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* readdir in userspace.
*/
#include <linux/compat.h>
#include <linux/fs_stack.h>
#include <linux/security.h>
#include "aufs.h"
/* bits for struct aufs_rdu.flags */
#define AuRdu_CALLED 1
#define AuRdu_CONT (1 << 1)
#define AuRdu_FULL (1 << 2)
#define au_ftest_rdu(flags, name) ((flags) & AuRdu_##name)
#define au_fset_rdu(flags, name) \
do { (flags) |= AuRdu_##name; } while (0)
#define au_fclr_rdu(flags, name) \
do { (flags) &= ~AuRdu_##name; } while (0)
struct au_rdu_arg {
struct dir_context ctx;
struct aufs_rdu *rdu;
union au_rdu_ent_ul ent;
unsigned long end;
struct super_block *sb;
int err;
};
static int au_rdu_fill(struct dir_context *ctx, const char *name, int nlen,
loff_t offset, u64 h_ino, unsigned int d_type)
{
int err, len;
struct au_rdu_arg *arg = container_of(ctx, struct au_rdu_arg, ctx);
struct aufs_rdu *rdu = arg->rdu;
struct au_rdu_ent ent;
err = 0;
arg->err = 0;
au_fset_rdu(rdu->cookie.flags, CALLED);
len = au_rdu_len(nlen);
if (arg->ent.ul + len < arg->end) {
ent.ino = h_ino;
ent.bindex = rdu->cookie.bindex;
ent.type = d_type;
ent.nlen = nlen;
if (unlikely(nlen > AUFS_MAX_NAMELEN))
ent.type = DT_UNKNOWN;
/* unnecessary to support mmap_sem since this is a dir */
err = -EFAULT;
if (copy_to_user(arg->ent.e, &ent, sizeof(ent)))
goto out;
if (copy_to_user(arg->ent.e->name, name, nlen))
goto out;
/* the terminating NULL */
if (__put_user(0, arg->ent.e->name + nlen))
goto out;
err = 0;
/* AuDbg("%p, %.*s\n", arg->ent.p, nlen, name); */
arg->ent.ul += len;
rdu->rent++;
} else {
err = -EFAULT;
au_fset_rdu(rdu->cookie.flags, FULL);
rdu->full = 1;
rdu->tail = arg->ent;
}
out:
/* AuTraceErr(err); */
return err;
}
static int au_rdu_do(struct file *h_file, struct au_rdu_arg *arg)
{
int err;
loff_t offset;
struct au_rdu_cookie *cookie = &arg->rdu->cookie;
/* we don't have to care (FMODE_32BITHASH | FMODE_64BITHASH) for ext4 */
offset = vfsub_llseek(h_file, cookie->h_pos, SEEK_SET);
err = offset;
if (unlikely(offset != cookie->h_pos))
goto out;
err = 0;
do {
arg->err = 0;
au_fclr_rdu(cookie->flags, CALLED);
/* smp_mb(); */
err = vfsub_iterate_dir(h_file, &arg->ctx);
if (err >= 0)
err = arg->err;
} while (!err
&& au_ftest_rdu(cookie->flags, CALLED)
&& !au_ftest_rdu(cookie->flags, FULL));
cookie->h_pos = h_file->f_pos;
out:
AuTraceErr(err);
return err;
}
static int au_rdu(struct file *file, struct aufs_rdu *rdu)
{
int err;
aufs_bindex_t bbot;
struct au_rdu_arg arg = {
.ctx = {
.actor = au_rdu_fill
}
};
struct dentry *dentry;
struct inode *inode;
struct file *h_file;
struct au_rdu_cookie *cookie = &rdu->cookie;
err = !access_ok(VERIFY_WRITE, rdu->ent.e, rdu->sz);
if (unlikely(err)) {
err = -EFAULT;
AuTraceErr(err);
goto out;
}
rdu->rent = 0;
rdu->tail = rdu->ent;
rdu->full = 0;
arg.rdu = rdu;
arg.ent = rdu->ent;
arg.end = arg.ent.ul;
arg.end += rdu->sz;
err = -ENOTDIR;
if (unlikely(!file->f_op->iterate && !file->f_op->iterate_shared))
goto out;
err = security_file_permission(file, MAY_READ);
AuTraceErr(err);
if (unlikely(err))
goto out;
dentry = file->f_path.dentry;
inode = d_inode(dentry);
inode_lock_shared(inode);
arg.sb = inode->i_sb;
err = si_read_lock(arg.sb, AuLock_FLUSH | AuLock_NOPLM);
if (unlikely(err))
goto out_mtx;
err = au_alive_dir(dentry);
if (unlikely(err))
goto out_si;
/* todo: reval? */
fi_read_lock(file);
err = -EAGAIN;
if (unlikely(au_ftest_rdu(cookie->flags, CONT)
&& cookie->generation != au_figen(file)))
goto out_unlock;
err = 0;
if (!rdu->blk) {
rdu->blk = au_sbi(arg.sb)->si_rdblk;
if (!rdu->blk)
rdu->blk = au_dir_size(file, /*dentry*/NULL);
}
bbot = au_fbtop(file);
if (cookie->bindex < bbot)
cookie->bindex = bbot;
bbot = au_fbbot_dir(file);
/* AuDbg("b%d, b%d\n", cookie->bindex, bbot); */
for (; !err && cookie->bindex <= bbot;
cookie->bindex++, cookie->h_pos = 0) {
h_file = au_hf_dir(file, cookie->bindex);
if (!h_file)
continue;
au_fclr_rdu(cookie->flags, FULL);
err = au_rdu_do(h_file, &arg);
AuTraceErr(err);
if (unlikely(au_ftest_rdu(cookie->flags, FULL) || err))
break;
}
AuDbg("rent %llu\n", rdu->rent);
if (!err && !au_ftest_rdu(cookie->flags, CONT)) {
rdu->shwh = !!au_opt_test(au_sbi(arg.sb)->si_mntflags, SHWH);
au_fset_rdu(cookie->flags, CONT);
cookie->generation = au_figen(file);
}
ii_read_lock_child(inode);
fsstack_copy_attr_atime(inode, au_h_iptr(inode, au_ibtop(inode)));
ii_read_unlock(inode);
out_unlock:
fi_read_unlock(file);
out_si:
si_read_unlock(arg.sb);
out_mtx:
inode_unlock_shared(inode);
out:
AuTraceErr(err);
return err;
}
static int au_rdu_ino(struct file *file, struct aufs_rdu *rdu)
{
int err;
ino_t ino;
unsigned long long nent;
union au_rdu_ent_ul *u;
struct au_rdu_ent ent;
struct super_block *sb;
err = 0;
nent = rdu->nent;
u = &rdu->ent;
sb = file->f_path.dentry->d_sb;
si_read_lock(sb, AuLock_FLUSH);
while (nent-- > 0) {
/* unnecessary to support mmap_sem since this is a dir */
err = copy_from_user(&ent, u->e, sizeof(ent));
if (!err)
err = !access_ok(VERIFY_WRITE, &u->e->ino, sizeof(ino));
if (unlikely(err)) {
err = -EFAULT;
AuTraceErr(err);
break;
}
/* AuDbg("b%d, i%llu\n", ent.bindex, ent.ino); */
if (!ent.wh)
err = au_ino(sb, ent.bindex, ent.ino, ent.type, &ino);
else
err = au_wh_ino(sb, ent.bindex, ent.ino, ent.type,
&ino);
if (unlikely(err)) {
AuTraceErr(err);
break;
}
err = __put_user(ino, &u->e->ino);
if (unlikely(err)) {
err = -EFAULT;
AuTraceErr(err);
break;
}
u->ul += au_rdu_len(ent.nlen);
}
si_read_unlock(sb);
return err;
}
/* ---------------------------------------------------------------------- */
static int au_rdu_verify(struct aufs_rdu *rdu)
{
AuDbg("rdu{%llu, %p, %u | %u | %llu, %u, %u | "
"%llu, b%d, 0x%x, g%u}\n",
rdu->sz, rdu->ent.e, rdu->verify[AufsCtlRduV_SZ],
rdu->blk,
rdu->rent, rdu->shwh, rdu->full,
rdu->cookie.h_pos, rdu->cookie.bindex, rdu->cookie.flags,
rdu->cookie.generation);
if (rdu->verify[AufsCtlRduV_SZ] == sizeof(*rdu))
return 0;
AuDbg("%u:%u\n",
rdu->verify[AufsCtlRduV_SZ], (unsigned int)sizeof(*rdu));
return -EINVAL;
}
long au_rdu_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
long err, e;
struct aufs_rdu rdu;
void __user *p = (void __user *)arg;
err = copy_from_user(&rdu, p, sizeof(rdu));
if (unlikely(err)) {
err = -EFAULT;
AuTraceErr(err);
goto out;
}
err = au_rdu_verify(&rdu);
if (unlikely(err))
goto out;
switch (cmd) {
case AUFS_CTL_RDU:
err = au_rdu(file, &rdu);
if (unlikely(err))
break;
e = copy_to_user(p, &rdu, sizeof(rdu));
if (unlikely(e)) {
err = -EFAULT;
AuTraceErr(err);
}
break;
case AUFS_CTL_RDU_INO:
err = au_rdu_ino(file, &rdu);
break;
default:
/* err = -ENOTTY; */
err = -EINVAL;
}
out:
AuTraceErr(err);
return err;
}
#ifdef CONFIG_COMPAT
long au_rdu_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
long err, e;
struct aufs_rdu rdu;
void __user *p = compat_ptr(arg);
/* todo: get_user()? */
err = copy_from_user(&rdu, p, sizeof(rdu));
if (unlikely(err)) {
err = -EFAULT;
AuTraceErr(err);
goto out;
}
rdu.ent.e = compat_ptr(rdu.ent.ul);
err = au_rdu_verify(&rdu);
if (unlikely(err))
goto out;
switch (cmd) {
case AUFS_CTL_RDU:
err = au_rdu(file, &rdu);
if (unlikely(err))
break;
rdu.ent.ul = ptr_to_compat(rdu.ent.e);
rdu.tail.ul = ptr_to_compat(rdu.tail.e);
e = copy_to_user(p, &rdu, sizeof(rdu));
if (unlikely(e)) {
err = -EFAULT;
AuTraceErr(err);
}
break;
case AUFS_CTL_RDU_INO:
err = au_rdu_ino(file, &rdu);
break;
default:
/* err = -ENOTTY; */
err = -EINVAL;
}
out:
AuTraceErr(err);
return err;
}
#endif
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