/*
* Invent attributes for ptyfsnode (vp) and store
* them in (vap).
* Directories lengths are returned as zero since
* any real length would require the genuine size
* to be computed, and nothing cares anyway.
*
* this is relatively minimal for ptyfs.
*/
int
ptyfs_getattr(void *v)
{
struct vop_getattr_args /* {
struct vnode *a_vp;
struct vattr *a_vap;
kauth_cred_t a_cred;
} */ *ap = v;
struct ptyfsnode *ptyfs = VTOPTYFS(ap->a_vp);
struct vattr *vap = ap->a_vap;
PTYFS_ITIMES(ptyfs, NULL, NULL, NULL);
/* start by zeroing out the attributes */
VATTR_NULL(vap);
/* next do all the common fields */
vap->va_type = ap->a_vp->v_type;
vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsidx.__fsid_val[0];
vap->va_fileid = ptyfs->ptyfs_fileno;
vap->va_gen = 0;
vap->va_flags = 0;
vap->va_nlink = 1;
vap->va_blocksize = PAGE_SIZE;
vap->va_atime = ptyfs->ptyfs_atime;
vap->va_mtime = ptyfs->ptyfs_mtime;
vap->va_ctime = ptyfs->ptyfs_ctime;
vap->va_birthtime = ptyfs->ptyfs_birthtime;
vap->va_mode = ptyfs->ptyfs_mode;
vap->va_flags = ptyfs->ptyfs_flags;
vap->va_uid = ptyfs->ptyfs_uid;
vap->va_gid = ptyfs->ptyfs_gid;
switch (ptyfs->ptyfs_type) {
case PTYFSpts:
case PTYFSptc:
if (pty_isfree(ptyfs->ptyfs_pty, 1))
return ENOENT;
vap->va_bytes = vap->va_size = 0;
vap->va_rdev = ap->a_vp->v_rdev;
break;
case PTYFSroot:
vap->va_rdev = 0;
vap->va_bytes = vap->va_size = DEV_BSIZE;
break;
default:
return EOPNOTSUPP;
}
return 0;
}
/*
* lookup. this is incredibly complicated in the
* general case, however for most pseudo-filesystems
* very little needs to be done.
*
* Locking isn't hard here, just poorly documented.
*
* If we're looking up ".", just vref the parent & return it.
*
* If we're looking up "..", unlock the parent, and lock "..". If everything
* went ok, try to re-lock the parent. We do this to prevent lock races.
*
* For anything else, get the needed node.
*
* We try to exit with the parent locked in error cases.
*/
int
ptyfs_lookup(void *v)
{
struct vop_lookup_v2_args /* {
struct vnode * a_dvp;
struct vnode ** a_vpp;
struct componentname * a_cnp;
} */ *ap = v;
struct componentname *cnp = ap->a_cnp;
struct vnode **vpp = ap->a_vpp;
struct vnode *dvp = ap->a_dvp;
const char *pname = cnp->cn_nameptr;
struct ptyfsnode *ptyfs;
int pty, error;
*vpp = NULL;
if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)
return EROFS;
if (cnp->cn_namelen == 1 && *pname == '.') {
*vpp = dvp;
vref(dvp);
return 0;
}
ptyfs = VTOPTYFS(dvp);
switch (ptyfs->ptyfs_type) {
case PTYFSroot:
/*
* Shouldn't get here with .. in the root node.
*/
if (cnp->cn_flags & ISDOTDOT)
return EIO;
pty = atoi(pname, cnp->cn_namelen);
if (pty < 0 || pty >= npty || pty_isfree(pty, 1))
break;
error = ptyfs_allocvp(dvp->v_mount, vpp, PTYFSpts, pty,
curlwp);
if (error)
return error;
VOP_UNLOCK(*vpp);
return 0;
default:
return ENOTDIR;
}
return cnp->cn_nameiop == LOOKUP ? ENOENT : EROFS;
}
static dev_t
pty_getfree(void)
{
extern kmutex_t pt_softc_mutex;
int i;
mutex_enter(&pt_softc_mutex);
for (i = 0; i < npty; i++) {
if (pty_isfree(i, 0))
break;
}
mutex_exit(&pt_softc_mutex);
return pty_makedev('t', i);
}
int
ptmioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
{
dev_t newdev, error;
struct pt_softc * pti;
struct nameidata cnd, snd;
struct filedesc *fdp = p->p_fd;
struct file *cfp = NULL, *sfp = NULL;
int cindx, sindx;
uid_t uid;
gid_t gid;
struct vattr vattr;
struct ucred *cred;
struct ptmget *ptm = (struct ptmget *)data;
error = 0;
switch (cmd) {
case PTMGET:
fdplock(fdp);
/* Grab two filedescriptors. */
if ((error = falloc(p, &cfp, &cindx)) != 0) {
fdpunlock(fdp);
break;
}
if ((error = falloc(p, &sfp, &sindx)) != 0) {
fdremove(fdp, cindx);
closef(cfp, p);
fdpunlock(fdp);
break;
}
retry:
/* Find and open a free master pty. */
newdev = pty_getfree();
if ((error = check_pty(minor(newdev))))
goto bad;
pti = pt_softc[minor(newdev)];
NDINIT(&cnd, LOOKUP, NOFOLLOW|LOCKLEAF, UIO_SYSSPACE,
pti->pty_pn, p);
if ((error = ptm_vn_open(&cnd)) != 0) {
/*
* Check if the master open failed because we lost
* the race to grab it.
*/
if (error == EIO && !pty_isfree(minor(newdev)))
goto retry;
goto bad;
}
cfp->f_flag = FREAD|FWRITE;
cfp->f_type = DTYPE_VNODE;
cfp->f_ops = &vnops;
cfp->f_data = (caddr_t) cnd.ni_vp;
VOP_UNLOCK(cnd.ni_vp, 0, p);
/*
* Open the slave.
* namei -> setattr -> unlock -> revoke -> vrele ->
* namei -> open -> unlock
* Three stage rocket:
* 1. Change the owner and permissions on the slave.
* 2. Revoke all the users of the slave.
* 3. open the slave.
*/
NDINIT(&snd, LOOKUP, NOFOLLOW|LOCKLEAF, UIO_SYSSPACE,
pti->pty_sn, p);
if ((error = namei(&snd)) != 0)
goto bad;
if ((snd.ni_vp->v_mount->mnt_flag & MNT_RDONLY) == 0) {
gid = tty_gid;
/* get real uid */
uid = p->p_cred->p_ruid;
VATTR_NULL(&vattr);
vattr.va_uid = uid;
vattr.va_gid = gid;
vattr.va_mode = (S_IRUSR|S_IWUSR|S_IWGRP) & ALLPERMS;
/* Get a fake cred to pretend we're root. */
cred = crget();
error = VOP_SETATTR(snd.ni_vp, &vattr, cred, p);
crfree(cred);
if (error) {
vput(snd.ni_vp);
goto bad;
}
}
VOP_UNLOCK(snd.ni_vp, 0, p);
if (snd.ni_vp->v_usecount > 1 ||
(snd.ni_vp->v_flag & (VALIASED)))
VOP_REVOKE(snd.ni_vp, REVOKEALL);
/*
* The vnode is useless after the revoke, we need to
* namei again.
*/
vrele(snd.ni_vp);
NDINIT(&snd, LOOKUP, NOFOLLOW|LOCKLEAF, UIO_SYSSPACE,
pti->pty_sn, p);
/* now open it */
if ((error = ptm_vn_open(&snd)) != 0)
goto bad;
sfp->f_flag = FREAD|FWRITE;
sfp->f_type = DTYPE_VNODE;
sfp->f_ops = &vnops;
sfp->f_data = (caddr_t) snd.ni_vp;
VOP_UNLOCK(snd.ni_vp, 0, p);
/* now, put the indexen and names into struct ptmget */
ptm->cfd = cindx;
ptm->sfd = sindx;
memcpy(ptm->cn, pti->pty_pn, sizeof(pti->pty_pn));
memcpy(ptm->sn, pti->pty_sn, sizeof(pti->pty_sn));
/* mark the files mature now that we've passed all errors */
FILE_SET_MATURE(cfp);
FILE_SET_MATURE(sfp);
fdpunlock(fdp);
break;
default:
error = EINVAL;
break;
}
return (error);
bad:
fdremove(fdp, cindx);
closef(cfp, p);
fdremove(fdp, sindx);
closef(sfp, p);
fdpunlock(fdp);
return (error);
}
/*
* readdir returns directory entries from ptyfsnode (vp).
*
* the strategy here with ptyfs is to generate a single
* directory entry at a time (struct dirent) and then
* copy that out to userland using uiomove. a more efficent
* though more complex implementation, would try to minimize
* the number of calls to uiomove(). for ptyfs, this is
* hardly worth the added code complexity.
*
* this should just be done through read()
*/
int
ptyfs_readdir(void *v)
{
struct vop_readdir_args /* {
struct vnode *a_vp;
struct uio *a_uio;
kauth_cred_t a_cred;
int *a_eofflag;
off_t **a_cookies;
int *a_ncookies;
} */ *ap = v;
struct uio *uio = ap->a_uio;
struct dirent *dp;
struct ptyfsnode *ptyfs;
off_t i;
int error;
off_t *cookies = NULL;
int ncookies;
struct vnode *vp;
int nc = 0;
vp = ap->a_vp;
ptyfs = VTOPTYFS(vp);
if (uio->uio_resid < UIO_MX)
return EINVAL;
if (uio->uio_offset < 0)
return EINVAL;
dp = malloc(sizeof(struct dirent), M_PTYFSTMP, M_WAITOK | M_ZERO);
error = 0;
i = uio->uio_offset;
dp->d_reclen = UIO_MX;
ncookies = uio->uio_resid / UIO_MX;
if (ptyfs->ptyfs_type != PTYFSroot) {
error = ENOTDIR;
goto out;
}
if (i >= npty)
goto out;
if (ap->a_ncookies) {
ncookies = min(ncookies, (npty + 2 - i));
cookies = malloc(ncookies * sizeof (off_t),
M_TEMP, M_WAITOK);
*ap->a_cookies = cookies;
}
for (; i < 2; i++) {
/* `.' and/or `..' */
dp->d_fileno = PTYFS_FILENO(0, PTYFSroot);
dp->d_namlen = i + 1;
(void)memcpy(dp->d_name, "..", dp->d_namlen);
dp->d_name[i + 1] = '\0';
dp->d_type = DT_DIR;
if ((error = uiomove(dp, UIO_MX, uio)) != 0)
goto out;
if (cookies)
*cookies++ = i + 1;
nc++;
}
for (; uio->uio_resid >= UIO_MX && i < npty; i++) {
/* check for used ptys */
if (pty_isfree(i - 2, 1))
continue;
dp->d_fileno = PTYFS_FILENO(i - 2, PTYFSpts);
dp->d_namlen = snprintf(dp->d_name, sizeof(dp->d_name),
"%lld", (long long)(i - 2));
dp->d_type = DT_CHR;
if ((error = uiomove(dp, UIO_MX, uio)) != 0)
goto out;
if (cookies)
*cookies++ = i + 1;
nc++;
}
out:
/* not pertinent in error cases */
ncookies = nc;
if (ap->a_ncookies) {
if (error) {
if (cookies)
free(*ap->a_cookies, M_TEMP);
*ap->a_ncookies = 0;
*ap->a_cookies = NULL;
} else
*ap->a_ncookies = ncookies;
}
uio->uio_offset = i;
free(dp, M_PTYFSTMP);
return error;
}
static int
pty_alloc_master(struct lwp *l, int *fd, dev_t *dev, struct mount *mp)
{
int error;
struct file *fp;
struct vnode *vp;
int md;
if ((error = fd_allocfile(&fp, fd)) != 0) {
DPRINTF(("fd_allocfile %d\n", error));
return error;
}
retry:
/* Find and open a free master pty. */
*dev = pty_getfree();
md = minor(*dev);
if ((error = pty_check(md)) != 0) {
DPRINTF(("pty_check %d\n", error));
goto bad;
}
if (ptm == NULL) {
DPRINTF(("no ptm\n"));
error = EOPNOTSUPP;
goto bad;
}
/*
* XXX Since PTYFS has now multiple instance support, if we mounted
* more than one PTYFS we must check here the ptyfs_used_tbl, to find
* out if the ptyfsnode is under the appropriate mount and skip the
* node if not, because the pty could has been released, but
* ptyfs_reclaim didn't get a chance to release the corresponding
* node other mount point yet.
*
* It's important to have only one mount point's ptyfsnode for each
* appropriate device in ptyfs_used_tbl, else we will have a security
* problem, because every entry will have access to this device.
*
* Also we will not have not efficient vnode and memory usage.
* You can test this by changing a_recycle from true to false
* in ptyfs_inactive.
*/
if ((error = (*ptm->allocvp)(mp, l, &vp, *dev, 'p')) != 0) {
DPRINTF(("pty_allocvp %d\n", error));
goto bad;
}
if ((error = pty_vn_open(vp, l)) != 0) {
DPRINTF(("pty_vn_open %d\n", error));
/*
* Check if the master open failed because we lost
* the race to grab it.
*/
if (error != EIO)
goto bad;
error = !pty_isfree(md, 1);
DPRINTF(("pty_isfree %d\n", error));
if (error)
goto retry;
else
goto bad;
}
fp->f_flag = FREAD|FWRITE;
fp->f_type = DTYPE_VNODE;
fp->f_ops = &vnops;
fp->f_data = vp;
VOP_UNLOCK(vp);
fd_affix(curproc, fp, *fd);
return 0;
bad:
fd_abort(curproc, fp, *fd);
return error;
}
