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vfs_syscalls.c
3442 lines (3088 loc) · 75.8 KB
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vfs_syscalls.c
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/* $OpenBSD: vfs_syscalls.c,v 1.356 2022/02/17 03:12:34 rob Exp $ */
/* $NetBSD: vfs_syscalls.c,v 1.71 1996/04/23 10:29:02 mycroft Exp $ */
/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)vfs_syscalls.c 8.28 (Berkeley) 12/10/94
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/namei.h>
#include <sys/filedesc.h>
#include <sys/kernel.h>
#include <sys/conf.h>
#include <sys/sysctl.h>
#include <sys/fcntl.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/lock.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/proc.h>
#include <sys/pledge.h>
#include <sys/uio.h>
#include <sys/malloc.h>
#include <sys/pool.h>
#include <sys/dkio.h>
#include <sys/disklabel.h>
#include <sys/ktrace.h>
#include <sys/unistd.h>
#include <sys/specdev.h>
#include <sys/syscallargs.h>
extern int suid_clear;
static int change_dir(struct nameidata *, struct proc *);
void checkdirs(struct vnode *);
int copyout_statfs(struct statfs *, void *, struct proc *);
int doopenat(struct proc *, int, const char *, int, mode_t, register_t *);
int domknodat(struct proc *, int, const char *, mode_t, dev_t);
int dolinkat(struct proc *, int, const char *, int, const char *, int);
int dosymlinkat(struct proc *, const char *, int, const char *);
int dounlinkat(struct proc *, int, const char *, int);
int dofaccessat(struct proc *, int, const char *, int, int);
int dofstatat(struct proc *, int, const char *, struct stat *, int);
int doreadlinkat(struct proc *, int, const char *, char *, size_t,
register_t *);
int dochflagsat(struct proc *, int, const char *, u_int, int);
int dovchflags(struct proc *, struct vnode *, u_int);
int dofchmodat(struct proc *, int, const char *, mode_t, int);
int dofchownat(struct proc *, int, const char *, uid_t, gid_t, int);
int dorenameat(struct proc *, int, const char *, int, const char *);
int domkdirat(struct proc *, int, const char *, mode_t);
int doutimensat(struct proc *, int, const char *, struct timespec [2], int);
int dovutimens(struct proc *, struct vnode *, struct timespec [2]);
int dofutimens(struct proc *, int, struct timespec [2]);
int dounmount_leaf(struct mount *, int, struct proc *);
/*
* Virtual File System System Calls
*/
/*
* Mount a file system.
*/
int
sys_mount(struct proc *p, void *v, register_t *retval)
{
struct sys_mount_args /* {
syscallarg(const char *) type;
syscallarg(const char *) path;
syscallarg(int) flags;
syscallarg(void *) data;
} */ *uap = v;
struct vnode *vp;
struct mount *mp;
int error, mntflag = 0;
char fstypename[MFSNAMELEN];
char fspath[MNAMELEN];
struct nameidata nd;
struct vfsconf *vfsp;
int flags = SCARG(uap, flags);
void *args = NULL;
if ((error = suser(p)))
return (error);
/*
* Mount points must fit in MNAMELEN, not MAXPATHLEN.
*/
error = copyinstr(SCARG(uap, path), fspath, MNAMELEN, NULL);
if (error)
return(error);
/*
* Get vnode to be covered
*/
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, fspath, p);
if ((error = namei(&nd)) != 0)
goto fail;
vp = nd.ni_vp;
if (flags & MNT_UPDATE) {
if ((vp->v_flag & VROOT) == 0) {
vput(vp);
error = EINVAL;
goto fail;
}
mp = vp->v_mount;
vfsp = mp->mnt_vfc;
args = malloc(vfsp->vfc_datasize, M_TEMP, M_WAITOK | M_ZERO);
error = copyin(SCARG(uap, data), args, vfsp->vfc_datasize);
if (error) {
vput(vp);
goto fail;
}
mntflag = mp->mnt_flag;
/*
* We only allow the filesystem to be reloaded if it
* is currently mounted read-only.
*/
if ((flags & MNT_RELOAD) &&
((mp->mnt_flag & MNT_RDONLY) == 0)) {
vput(vp);
error = EOPNOTSUPP; /* Needs translation */
goto fail;
}
if ((error = vfs_busy(mp, VB_READ|VB_NOWAIT)) != 0) {
vput(vp);
goto fail;
}
mp->mnt_flag |= flags & (MNT_RELOAD | MNT_UPDATE);
goto update;
}
/*
* Do not allow disabling of permission checks unless exec and access to
* device files is disabled too.
*/
if ((flags & MNT_NOPERM) &&
(flags & (MNT_NODEV | MNT_NOEXEC)) != (MNT_NODEV | MNT_NOEXEC)) {
vput(vp);
error = EPERM;
goto fail;
}
if ((error = vinvalbuf(vp, V_SAVE, p->p_ucred, p, 0, INFSLP)) != 0) {
vput(vp);
goto fail;
}
if (vp->v_type != VDIR) {
vput(vp);
goto fail;
}
error = copyinstr(SCARG(uap, type), fstypename, MFSNAMELEN, NULL);
if (error) {
vput(vp);
goto fail;
}
vfsp = vfs_byname(fstypename);
if (vfsp == NULL) {
vput(vp);
error = EOPNOTSUPP;
goto fail;
}
args = malloc(vfsp->vfc_datasize, M_TEMP, M_WAITOK | M_ZERO);
error = copyin(SCARG(uap, data), args, vfsp->vfc_datasize);
if (error) {
vput(vp);
goto fail;
}
if (vp->v_mountedhere != NULL) {
vput(vp);
error = EBUSY;
goto fail;
}
/*
* Allocate and initialize the file system.
*/
mp = vfs_mount_alloc(vp, vfsp);
mp->mnt_stat.f_owner = p->p_ucred->cr_uid;
update:
/* Ensure that the parent mountpoint does not get unmounted. */
error = vfs_busy(vp->v_mount, VB_READ|VB_NOWAIT|VB_DUPOK);
if (error) {
if (mp->mnt_flag & MNT_UPDATE) {
mp->mnt_flag = mntflag;
vfs_unbusy(mp);
} else {
vfs_unbusy(mp);
vfs_mount_free(mp);
}
vput(vp);
goto fail;
}
/*
* Set the mount level flags.
*/
if (flags & MNT_RDONLY)
mp->mnt_flag |= MNT_RDONLY;
else if (mp->mnt_flag & MNT_RDONLY)
mp->mnt_flag |= MNT_WANTRDWR;
mp->mnt_flag &=~ (MNT_NOSUID | MNT_NOEXEC | MNT_WXALLOWED | MNT_NODEV |
MNT_SYNCHRONOUS | MNT_ASYNC | MNT_SOFTDEP | MNT_NOATIME |
MNT_NOPERM | MNT_FORCE);
mp->mnt_flag |= flags & (MNT_NOSUID | MNT_NOEXEC | MNT_WXALLOWED |
MNT_NODEV | MNT_SYNCHRONOUS | MNT_ASYNC | MNT_SOFTDEP |
MNT_NOATIME | MNT_NOPERM | MNT_FORCE);
/*
* Mount the filesystem.
*/
error = VFS_MOUNT(mp, fspath, args, &nd, p);
if (!error) {
mp->mnt_stat.f_ctime = gettime();
}
if (mp->mnt_flag & MNT_UPDATE) {
vfs_unbusy(vp->v_mount);
vput(vp);
if (mp->mnt_flag & MNT_WANTRDWR)
mp->mnt_flag &= ~MNT_RDONLY;
mp->mnt_flag &= ~MNT_OP_FLAGS;
if (error)
mp->mnt_flag = mntflag;
if ((mp->mnt_flag & MNT_RDONLY) == 0) {
if (mp->mnt_syncer == NULL)
error = vfs_allocate_syncvnode(mp);
} else {
if (mp->mnt_syncer != NULL)
vgone(mp->mnt_syncer);
mp->mnt_syncer = NULL;
}
vfs_unbusy(mp);
goto fail;
}
mp->mnt_flag &= ~MNT_OP_FLAGS;
vp->v_mountedhere = mp;
/*
* Put the new filesystem on the mount list after root.
*/
cache_purge(vp);
if (!error) {
TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
checkdirs(vp);
vfs_unbusy(vp->v_mount);
VOP_UNLOCK(vp);
if ((mp->mnt_flag & MNT_RDONLY) == 0)
error = vfs_allocate_syncvnode(mp);
vfs_unbusy(mp);
(void) VFS_STATFS(mp, &mp->mnt_stat, p);
if ((error = VFS_START(mp, 0, p)) != 0)
vrele(vp);
} else {
mp->mnt_vnodecovered->v_mountedhere = NULL;
vfs_unbusy(mp);
vfs_mount_free(mp);
vfs_unbusy(vp->v_mount);
vput(vp);
}
fail:
if (args)
free(args, M_TEMP, vfsp->vfc_datasize);
return (error);
}
/*
* Scan all active processes to see if any of them have a current
* or root directory onto which the new filesystem has just been
* mounted. If so, replace them with the new mount point, keeping
* track of how many were replaced. That's the number of references
* the old vnode had that we've replaced, so finish by vrele()'ing
* it that many times. This puts off any possible sleeping until
* we've finished walking the allprocess list.
*/
void
checkdirs(struct vnode *olddp)
{
struct filedesc *fdp;
struct vnode *newdp;
struct process *pr;
u_int free_count = 0;
if (olddp->v_usecount == 1)
return;
if (VFS_ROOT(olddp->v_mountedhere, &newdp))
panic("mount: lost mount");
LIST_FOREACH(pr, &allprocess, ps_list) {
fdp = pr->ps_fd;
if (fdp->fd_cdir == olddp) {
free_count++;
vref(newdp);
fdp->fd_cdir = newdp;
}
if (fdp->fd_rdir == olddp) {
free_count++;
vref(newdp);
fdp->fd_rdir = newdp;
}
}
if (rootvnode == olddp) {
free_count++;
vref(newdp);
rootvnode = newdp;
}
while (free_count-- > 0)
vrele(olddp);
vput(newdp);
}
/*
* Unmount a file system.
*
* Note: unmount takes a path to the vnode mounted on as argument,
* not special file (as before).
*/
int
sys_unmount(struct proc *p, void *v, register_t *retval)
{
struct sys_unmount_args /* {
syscallarg(const char *) path;
syscallarg(int) flags;
} */ *uap = v;
struct vnode *vp;
struct mount *mp;
int error;
struct nameidata nd;
if ((error = suser(p)) != 0)
return (error);
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_USERSPACE,
SCARG(uap, path), p);
if ((error = namei(&nd)) != 0)
return (error);
vp = nd.ni_vp;
mp = vp->v_mount;
/*
* Don't allow unmounting the root file system.
*/
if (mp->mnt_flag & MNT_ROOTFS) {
vput(vp);
return (EINVAL);
}
/*
* Must be the root of the filesystem
*/
if ((vp->v_flag & VROOT) == 0) {
vput(vp);
return (EINVAL);
}
vput(vp);
if (vfs_busy(mp, VB_WRITE|VB_WAIT))
return (EBUSY);
return (dounmount(mp, SCARG(uap, flags) & MNT_FORCE, p));
}
/*
* Do the actual file system unmount.
*/
int
dounmount(struct mount *mp, int flags, struct proc *p)
{
SLIST_HEAD(, mount) mplist;
struct mount *nmp;
int error;
SLIST_INIT(&mplist);
SLIST_INSERT_HEAD(&mplist, mp, mnt_dounmount);
/*
* Collect nested mount points. This takes advantage of the mount list
* being ordered - nested mount points come after their parent.
*/
while ((mp = TAILQ_NEXT(mp, mnt_list)) != NULL) {
SLIST_FOREACH(nmp, &mplist, mnt_dounmount) {
if (mp->mnt_vnodecovered == NULLVP ||
mp->mnt_vnodecovered->v_mount != nmp)
continue;
if ((flags & MNT_FORCE) == 0) {
error = EBUSY;
goto err;
}
error = vfs_busy(mp, VB_WRITE|VB_WAIT|VB_DUPOK);
if (error) {
if ((flags & MNT_DOOMED)) {
/*
* If the mount point was busy due to
* being unmounted, it has been removed
* from the mount list already.
* Restart the iteration from the last
* collected busy entry.
*/
mp = SLIST_FIRST(&mplist);
break;
}
goto err;
}
SLIST_INSERT_HEAD(&mplist, mp, mnt_dounmount);
break;
}
}
/*
* Nested mount points cannot appear during this loop as mounting
* requires a read lock for the parent mount point.
*/
while ((mp = SLIST_FIRST(&mplist)) != NULL) {
SLIST_REMOVE(&mplist, mp, mount, mnt_dounmount);
error = dounmount_leaf(mp, flags, p);
if (error)
goto err;
}
return (0);
err:
while ((mp = SLIST_FIRST(&mplist)) != NULL) {
SLIST_REMOVE(&mplist, mp, mount, mnt_dounmount);
vfs_unbusy(mp);
}
return (error);
}
int
dounmount_leaf(struct mount *mp, int flags, struct proc *p)
{
struct vnode *coveredvp;
struct vnode *vp, *nvp;
int error;
int hadsyncer = 0;
mp->mnt_flag &=~ MNT_ASYNC;
cache_purgevfs(mp); /* remove cache entries for this file sys */
if (mp->mnt_syncer != NULL) {
hadsyncer = 1;
vgone(mp->mnt_syncer);
mp->mnt_syncer = NULL;
}
/*
* Before calling file system unmount, make sure
* all unveils to vnodes in here are dropped.
*/
TAILQ_FOREACH_SAFE(vp , &mp->mnt_vnodelist, v_mntvnodes, nvp) {
unveil_removevnode(vp);
}
if (((mp->mnt_flag & MNT_RDONLY) ||
(error = VFS_SYNC(mp, MNT_WAIT, 0, p->p_ucred, p)) == 0) ||
(flags & MNT_FORCE))
error = VFS_UNMOUNT(mp, flags, p);
if (error && !(flags & MNT_DOOMED)) {
if ((mp->mnt_flag & MNT_RDONLY) == 0 && hadsyncer)
(void) vfs_allocate_syncvnode(mp);
vfs_unbusy(mp);
return (error);
}
TAILQ_REMOVE(&mountlist, mp, mnt_list);
if ((coveredvp = mp->mnt_vnodecovered) != NULLVP) {
coveredvp->v_mountedhere = NULL;
vrele(coveredvp);
}
if (!TAILQ_EMPTY(&mp->mnt_vnodelist))
panic("unmount: dangling vnode");
vfs_unbusy(mp);
vfs_mount_free(mp);
return (0);
}
/*
* Sync each mounted filesystem.
*/
int
sys_sync(struct proc *p, void *v, register_t *retval)
{
struct mount *mp;
int asyncflag;
TAILQ_FOREACH_REVERSE(mp, &mountlist, mntlist, mnt_list) {
if (vfs_busy(mp, VB_READ|VB_NOWAIT))
continue;
if ((mp->mnt_flag & MNT_RDONLY) == 0) {
asyncflag = mp->mnt_flag & MNT_ASYNC;
mp->mnt_flag &= ~MNT_ASYNC;
uvm_vnp_sync(mp);
VFS_SYNC(mp, MNT_NOWAIT, 0, p->p_ucred, p);
if (asyncflag)
mp->mnt_flag |= MNT_ASYNC;
}
vfs_unbusy(mp);
}
return (0);
}
/*
* Change filesystem quotas.
*/
int
sys_quotactl(struct proc *p, void *v, register_t *retval)
{
struct sys_quotactl_args /* {
syscallarg(const char *) path;
syscallarg(int) cmd;
syscallarg(int) uid;
syscallarg(char *) arg;
} */ *uap = v;
struct mount *mp;
int error;
struct nameidata nd;
NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
if ((error = namei(&nd)) != 0)
return (error);
mp = nd.ni_vp->v_mount;
vrele(nd.ni_vp);
return (VFS_QUOTACTL(mp, SCARG(uap, cmd), SCARG(uap, uid),
SCARG(uap, arg), p));
}
int
copyout_statfs(struct statfs *sp, void *uaddr, struct proc *p)
{
size_t co_sz1 = offsetof(struct statfs, f_fsid);
size_t co_off2 = co_sz1 + sizeof(fsid_t);
size_t co_sz2 = sizeof(struct statfs) - co_off2;
char *s, *d;
int error;
/* Don't let non-root see filesystem id (for NFS security) */
if (suser(p)) {
fsid_t fsid;
s = (char *)sp;
d = (char *)uaddr;
memset(&fsid, 0, sizeof(fsid));
if ((error = copyout(s, d, co_sz1)) != 0)
return (error);
if ((error = copyout(&fsid, d + co_sz1, sizeof(fsid))) != 0)
return (error);
return (copyout(s + co_off2, d + co_off2, co_sz2));
}
return (copyout(sp, uaddr, sizeof(*sp)));
}
/*
* Get filesystem statistics.
*/
int
sys_statfs(struct proc *p, void *v, register_t *retval)
{
struct sys_statfs_args /* {
syscallarg(const char *) path;
syscallarg(struct statfs *) buf;
} */ *uap = v;
struct mount *mp;
struct statfs *sp;
int error;
struct nameidata nd;
NDINIT(&nd, LOOKUP, FOLLOW | BYPASSUNVEIL, UIO_USERSPACE,
SCARG(uap, path), p);
nd.ni_pledge = PLEDGE_RPATH;
nd.ni_unveil = UNVEIL_READ;
if ((error = namei(&nd)) != 0)
return (error);
mp = nd.ni_vp->v_mount;
sp = &mp->mnt_stat;
vrele(nd.ni_vp);
if ((error = VFS_STATFS(mp, sp, p)) != 0)
return (error);
sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
return (copyout_statfs(sp, SCARG(uap, buf), p));
}
/*
* Get filesystem statistics.
*/
int
sys_fstatfs(struct proc *p, void *v, register_t *retval)
{
struct sys_fstatfs_args /* {
syscallarg(int) fd;
syscallarg(struct statfs *) buf;
} */ *uap = v;
struct file *fp;
struct mount *mp;
struct statfs *sp;
int error;
if ((error = getvnode(p, SCARG(uap, fd), &fp)) != 0)
return (error);
mp = ((struct vnode *)fp->f_data)->v_mount;
if (!mp) {
FRELE(fp, p);
return (ENOENT);
}
sp = &mp->mnt_stat;
error = VFS_STATFS(mp, sp, p);
FRELE(fp, p);
if (error)
return (error);
sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
return (copyout_statfs(sp, SCARG(uap, buf), p));
}
/*
* Get statistics on all filesystems.
*/
int
sys_getfsstat(struct proc *p, void *v, register_t *retval)
{
struct sys_getfsstat_args /* {
syscallarg(struct statfs *) buf;
syscallarg(size_t) bufsize;
syscallarg(int) flags;
} */ *uap = v;
struct mount *mp;
struct statfs *sp;
struct statfs *sfsp;
size_t count, maxcount;
int error, flags = SCARG(uap, flags);
maxcount = SCARG(uap, bufsize) / sizeof(struct statfs);
sfsp = SCARG(uap, buf);
count = 0;
TAILQ_FOREACH(mp, &mountlist, mnt_list) {
if (vfs_busy(mp, VB_READ|VB_NOWAIT))
continue;
if (sfsp && count < maxcount) {
sp = &mp->mnt_stat;
/* Refresh stats unless MNT_NOWAIT is specified */
if (flags != MNT_NOWAIT &&
flags != MNT_LAZY &&
(flags == MNT_WAIT ||
flags == 0) &&
(error = VFS_STATFS(mp, sp, p))) {
vfs_unbusy(mp);
continue;
}
sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
#if notyet
if (mp->mnt_flag & MNT_SOFTDEP)
sp->f_eflags = STATFS_SOFTUPD;
#endif
error = (copyout_statfs(sp, sfsp, p));
if (error) {
vfs_unbusy(mp);
return (error);
}
sfsp++;
}
count++;
vfs_unbusy(mp);
}
if (sfsp && count > maxcount)
*retval = maxcount;
else
*retval = count;
return (0);
}
/*
* Change current working directory to a given file descriptor.
*/
int
sys_fchdir(struct proc *p, void *v, register_t *retval)
{
struct sys_fchdir_args /* {
syscallarg(int) fd;
} */ *uap = v;
struct filedesc *fdp = p->p_fd;
struct vnode *vp, *tdp, *old_cdir;
struct mount *mp;
struct file *fp;
int error;
if ((fp = fd_getfile(fdp, SCARG(uap, fd))) == NULL)
return (EBADF);
vp = fp->f_data;
if (fp->f_type != DTYPE_VNODE || vp->v_type != VDIR) {
FRELE(fp, p);
return (ENOTDIR);
}
vref(vp);
FRELE(fp, p);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p);
while (!error && (mp = vp->v_mountedhere) != NULL) {
if (vfs_busy(mp, VB_READ|VB_WAIT))
continue;
error = VFS_ROOT(mp, &tdp);
vfs_unbusy(mp);
if (error)
break;
vput(vp);
vp = tdp;
}
if (error) {
vput(vp);
return (error);
}
VOP_UNLOCK(vp);
old_cdir = fdp->fd_cdir;
fdp->fd_cdir = vp;
vrele(old_cdir);
return (0);
}
/*
* Change current working directory (``.'').
*/
int
sys_chdir(struct proc *p, void *v, register_t *retval)
{
struct sys_chdir_args /* {
syscallarg(const char *) path;
} */ *uap = v;
struct filedesc *fdp = p->p_fd;
struct vnode *old_cdir;
int error;
struct nameidata nd;
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_USERSPACE,
SCARG(uap, path), p);
nd.ni_pledge = PLEDGE_RPATH;
nd.ni_unveil = UNVEIL_READ;
if ((error = change_dir(&nd, p)) != 0)
return (error);
old_cdir = fdp->fd_cdir;
fdp->fd_cdir = nd.ni_vp;
vrele(old_cdir);
return (0);
}
/*
* Change notion of root (``/'') directory.
*/
int
sys_chroot(struct proc *p, void *v, register_t *retval)
{
struct sys_chroot_args /* {
syscallarg(const char *) path;
} */ *uap = v;
struct filedesc *fdp = p->p_fd;
struct vnode *old_cdir, *old_rdir;
int error;
struct nameidata nd;
if ((error = suser(p)) != 0)
return (error);
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_USERSPACE,
SCARG(uap, path), p);
if ((error = change_dir(&nd, p)) != 0)
return (error);
if (fdp->fd_rdir != NULL) {
/*
* A chroot() done inside a changed root environment does
* an automatic chdir to avoid the out-of-tree experience.
*/
vref(nd.ni_vp);
old_rdir = fdp->fd_rdir;
old_cdir = fdp->fd_cdir;
fdp->fd_rdir = fdp->fd_cdir = nd.ni_vp;
vrele(old_rdir);
vrele(old_cdir);
} else
fdp->fd_rdir = nd.ni_vp;
atomic_setbits_int(&p->p_p->ps_flags, PS_CHROOT);
return (0);
}
/*
* Common routine for chroot and chdir.
*/
static int
change_dir(struct nameidata *ndp, struct proc *p)
{
struct vnode *vp;
int error;
if ((error = namei(ndp)) != 0)
return (error);
vp = ndp->ni_vp;
if (vp->v_type != VDIR)
error = ENOTDIR;
else
error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p);
if (error)
vput(vp);
else
VOP_UNLOCK(vp);
return (error);
}
int
sys___realpath(struct proc *p, void *v, register_t *retval)
{
struct sys___realpath_args /* {
syscallarg(const char *) pathname;
syscallarg(char *) resolved;
} */ *uap = v;
char *pathname;
char *rpbuf;
struct nameidata nd;
size_t pathlen;
int error = 0;
if (SCARG(uap, pathname) == NULL)
return (EINVAL);
pathname = pool_get(&namei_pool, PR_WAITOK);
rpbuf = pool_get(&namei_pool, PR_WAITOK);
if ((error = copyinstr(SCARG(uap, pathname), pathname, MAXPATHLEN,
&pathlen)))
goto end;
if (pathlen == 1) { /* empty string "" */
error = ENOENT;
goto end;
}
if (pathlen < 2) {
error = EINVAL;
goto end;
}
/* Get cwd for relative path if needed, prepend to rpbuf */
rpbuf[0] = '\0';
if (pathname[0] != '/') {
int cwdlen = MAXPATHLEN * 4; /* for vfs_getcwd_common */
char *cwdbuf, *bp;
cwdbuf = malloc(cwdlen, M_TEMP, M_WAITOK);
/* vfs_getcwd_common fills this in backwards */
bp = &cwdbuf[cwdlen - 1];
*bp = '\0';
error = vfs_getcwd_common(p->p_fd->fd_cdir, NULL, &bp, cwdbuf,
cwdlen/2, GETCWD_CHECK_ACCESS, p);
if (error) {
free(cwdbuf, M_TEMP, cwdlen);
goto end;
}
if (strlcpy(rpbuf, bp, MAXPATHLEN) >= MAXPATHLEN) {
free(cwdbuf, M_TEMP, cwdlen);
error = ENAMETOOLONG;
goto end;
}
free(cwdbuf, M_TEMP, cwdlen);
}
NDINIT(&nd, LOOKUP, FOLLOW | SAVENAME | REALPATH, UIO_SYSSPACE,
pathname, p);
nd.ni_cnd.cn_rpbuf = rpbuf;
nd.ni_cnd.cn_rpi = strlen(rpbuf);
nd.ni_pledge = PLEDGE_RPATH;
nd.ni_unveil = UNVEIL_READ;
if ((error = namei(&nd)) != 0)
goto end;
/* release reference from namei */
if (nd.ni_vp)
vrele(nd.ni_vp);
error = copyoutstr(nd.ni_cnd.cn_rpbuf, SCARG(uap, resolved),
MAXPATHLEN, NULL);
#ifdef KTRACE
if (KTRPOINT(p, KTR_NAMEI))
ktrnamei(p, nd.ni_cnd.cn_rpbuf);
#endif
pool_put(&namei_pool, nd.ni_cnd.cn_pnbuf);
end:
pool_put(&namei_pool, rpbuf);
pool_put(&namei_pool, pathname);
return (error);
}
int
sys_unveil(struct proc *p, void *v, register_t *retval)
{
struct sys_unveil_args /* {
syscallarg(const char *) path;
syscallarg(const char *) permissions;
} */ *uap = v;
struct process *pr = p->p_p;
char *pathname, *c;
struct nameidata nd;
size_t pathlen;
char permissions[5];
int error, allow;
if (SCARG(uap, path) == NULL && SCARG(uap, permissions) == NULL) {
pr->ps_uvdone = 1;
return (0);
}
if (pr->ps_uvdone != 0)
return EPERM;
error = copyinstr(SCARG(uap, permissions), permissions,
sizeof(permissions), NULL);
if (error)
return (error);
pathname = pool_get(&namei_pool, PR_WAITOK);
error = copyinstr(SCARG(uap, path), pathname, MAXPATHLEN, &pathlen);
if (error)
goto end;
#ifdef KTRACE
if (KTRPOINT(p, KTR_STRUCT))
ktrstruct(p, "unveil", permissions, strlen(permissions));
#endif
if (pathlen < 2) {
error = EINVAL;
goto end;
}
/* find root "/" or "//" */
for (c = pathname; *c != '\0'; c++) {
if (*c != '/')
break;
}
if (*c == '\0')
/* root directory */
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | SAVENAME,
UIO_SYSSPACE, pathname, p);
else
NDINIT(&nd, CREATE, FOLLOW | LOCKLEAF | LOCKPARENT | SAVENAME,
UIO_SYSSPACE, pathname, p);