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ptyfs_vfsops.c revision 1.28 
      1 /*	$NetBSD: ptyfs_vfsops.c,v 1.28 2007/07/31 21:14:18 pooka Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1992, 1993, 1995
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software donated to Berkeley by
      8  * Jan-Simon Pendry.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. Neither the name of the University nor the names of its contributors
     19  *    may be used to endorse or promote products derived from this software
     20  *    without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  *
     34  */
     35 
     36 /*
     37  * Pseudo-tty Filesystem
     38  */
     39 
     40 #include <sys/cdefs.h>
     41 __KERNEL_RCSID(0, "$NetBSD: ptyfs_vfsops.c,v 1.28 2007/07/31 21:14:18 pooka Exp $");
     42 
     43 #include <sys/param.h>
     44 #include <sys/systm.h>
     45 #include <sys/sysctl.h>
     46 #include <sys/conf.h>
     47 #include <sys/proc.h>
     48 #include <sys/vnode.h>
     49 #include <sys/mount.h>
     50 #include <sys/namei.h>
     51 #include <sys/stat.h>
     52 #include <sys/dirent.h>
     53 #include <sys/malloc.h>
     54 #include <sys/syslog.h>
     55 #include <sys/select.h>
     56 #include <sys/filedesc.h>
     57 #include <sys/tty.h>
     58 #include <sys/pty.h>
     59 #include <sys/kauth.h>
     60 
     61 #include <fs/ptyfs/ptyfs.h>
     62 #include <miscfs/specfs/specdev.h>
     63 
     64 MALLOC_JUSTDEFINE(M_PTYFSMNT, "ptyfs mount", "ptyfs mount structures");
     65 
     66 VFS_PROTOS(ptyfs);
     67 
     68 static int ptyfs__allocvp(struct ptm_pty *, struct lwp *, struct vnode **,
     69     dev_t, char);
     70 static int ptyfs__makename(struct ptm_pty *, struct lwp *, char *, size_t,
     71     dev_t, char);
     72 static void ptyfs__getvattr(struct ptm_pty *, struct lwp *, struct vattr *);
     73 
     74 /*
     75  * ptm glue: When we mount, we make ptm point to us.
     76  */
     77 struct ptm_pty *ptyfs_save_ptm;
     78 static int ptyfs_count;
     79 
     80 struct ptm_pty ptm_ptyfspty = {
     81 	ptyfs__allocvp,
     82 	ptyfs__makename,
     83 	ptyfs__getvattr,
     84 	NULL
     85 };
     86 
     87 static const char *
     88 ptyfs__getpath(struct lwp *l, const struct mount *mp)
     89 {
     90 #define MAXBUF (sizeof(mp->mnt_stat.f_mntonname) + 32)
     91 	struct cwdinfo *cwdi = l->l_proc->p_cwdi;
     92 	char *buf;
     93 	const char *rv;
     94 	size_t len;
     95 	char *bp;
     96 	int error;
     97 
     98 	rv = mp->mnt_stat.f_mntonname;
     99 	if (cwdi->cwdi_rdir == NULL)
    100 		return rv;
    101 
    102 	buf = malloc(MAXBUF, M_TEMP, M_WAITOK);
    103 	bp = buf + MAXBUF;
    104 	*--bp = '\0';
    105 	error = getcwd_common(cwdi->cwdi_rdir, rootvnode, &bp,
    106 	    buf, MAXBUF / 2, 0, l);
    107 	if (error)	/* XXX */
    108 		goto out;
    109 
    110 	len = strlen(bp);
    111 	if (len < sizeof(mp->mnt_stat.f_mntonname))	/* XXX */
    112 		rv += len;
    113 out:
    114 	free(buf, M_TEMP);
    115 	return rv;
    116 }
    117 
    118 static int
    119 ptyfs__makename(struct ptm_pty *pt, struct lwp *l, char *tbuf, size_t bufsiz,
    120     dev_t dev, char ms)
    121 {
    122 	struct mount *mp = pt->arg;
    123 	size_t len;
    124 
    125 	switch (ms) {
    126 	case 'p':
    127 		/* We don't provide access to the master, should we? */
    128 		len = snprintf(tbuf, bufsiz, "/dev/null");
    129 		break;
    130 	case 't':
    131 		len = snprintf(tbuf, bufsiz, "%s/%d", ptyfs__getpath(l, mp),
    132 		    minor(dev));
    133 		break;
    134 	default:
    135 		return EINVAL;
    136 	}
    137 
    138 	return len >= bufsiz ? ENOSPC : 0;
    139 }
    140 
    141 
    142 static int
    143 /*ARGSUSED*/
    144 ptyfs__allocvp(struct ptm_pty *pt, struct lwp *l, struct vnode **vpp,
    145     dev_t dev, char ms)
    146 {
    147 	struct mount *mp = pt->arg;
    148 	ptyfstype type;
    149 
    150 	switch (ms) {
    151 	case 'p':
    152 		type = PTYFSptc;
    153 		break;
    154 	case 't':
    155 		type = PTYFSpts;
    156 		break;
    157 	default:
    158 		return EINVAL;
    159 	}
    160 
    161 	return ptyfs_allocvp(mp, vpp, type, minor(dev), l);
    162 }
    163 
    164 
    165 static void
    166 ptyfs__getvattr(struct ptm_pty *pt, struct lwp *l, struct vattr *vattr)
    167 {
    168 	struct mount *mp = pt->arg;
    169 	struct ptyfsmount *pmnt = VFSTOPTY(mp);
    170 	VATTR_NULL(vattr);
    171 	/* get real uid */
    172 	vattr->va_uid = kauth_cred_getuid(l->l_cred);
    173 	vattr->va_gid = pmnt->pmnt_gid;
    174 	vattr->va_mode = pmnt->pmnt_mode;
    175 }
    176 
    177 
    178 void
    179 ptyfs_init(void)
    180 {
    181 
    182 	malloc_type_attach(M_PTYFSMNT);
    183 	ptyfs_hashinit();
    184 }
    185 
    186 void
    187 ptyfs_reinit(void)
    188 {
    189 	ptyfs_hashreinit();
    190 }
    191 
    192 void
    193 ptyfs_done(void)
    194 {
    195 
    196 	ptyfs_hashdone();
    197 	malloc_type_detach(M_PTYFSMNT);
    198 }
    199 
    200 /*
    201  * Mount the Pseudo tty params filesystem
    202  */
    203 int
    204 ptyfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len,
    205     struct lwp *l)
    206 {
    207 	int error = 0;
    208 	struct ptyfsmount *pmnt;
    209 	struct ptyfs_args *args = data;
    210 
    211 	if (*data_len < sizeof *args)
    212 		return EINVAL;
    213 
    214 	if (UIO_MX & (UIO_MX - 1)) {
    215 		log(LOG_ERR, "ptyfs: invalid directory entry size");
    216 		return EINVAL;
    217 	}
    218 
    219 	if (mp->mnt_flag & MNT_GETARGS) {
    220 		pmnt = VFSTOPTY(mp);
    221 		if (pmnt == NULL)
    222 			return EIO;
    223 		args->version = PTYFS_ARGSVERSION;
    224 		args->mode = pmnt->pmnt_mode;
    225 		args->gid = pmnt->pmnt_gid;
    226 		*data_len = sizeof *args;
    227 		return 0;
    228 	}
    229 
    230 	/* Don't allow more than one mount */
    231 	if (ptyfs_count)
    232 		return EBUSY;
    233 
    234 	if (mp->mnt_flag & MNT_UPDATE)
    235 		return EOPNOTSUPP;
    236 
    237 	if (args->version != PTYFS_ARGSVERSION)
    238 		return EINVAL;
    239 
    240 	pmnt = malloc(sizeof(struct ptyfsmount), M_UFSMNT, M_WAITOK);
    241 
    242 	mp->mnt_data = pmnt;
    243 	pmnt->pmnt_gid = args->gid;
    244 	pmnt->pmnt_mode = args->mode;
    245 	mp->mnt_flag |= MNT_LOCAL;
    246 	vfs_getnewfsid(mp);
    247 
    248 	if ((error = set_statvfs_info(path, UIO_USERSPACE, "ptyfs",
    249 	    UIO_SYSSPACE, mp->mnt_op->vfs_name, mp, l)) != 0) {
    250 		free(pmnt, M_UFSMNT);
    251 		return error;
    252 	}
    253 
    254 	/* Point pty access to us */
    255 
    256 	ptm_ptyfspty.arg = mp;
    257 	ptyfs_save_ptm = pty_sethandler(&ptm_ptyfspty);
    258 	ptyfs_count++;
    259 	return 0;
    260 }
    261 
    262 /*ARGSUSED*/
    263 int
    264 ptyfs_start(struct mount *mp, int flags,
    265     struct lwp *p)
    266 {
    267 	return 0;
    268 }
    269 
    270 /*ARGSUSED*/
    271 int
    272 ptyfs_unmount(struct mount *mp, int mntflags, struct lwp *p)
    273 {
    274 	int error;
    275 	int flags = 0;
    276 
    277 	if (mntflags & MNT_FORCE)
    278 		flags |= FORCECLOSE;
    279 
    280 	if ((error = vflush(mp, 0, flags)) != 0)
    281 		return (error);
    282 
    283 	/* Restore where pty access was pointing */
    284 	(void)pty_sethandler(ptyfs_save_ptm);
    285 	ptyfs_save_ptm = NULL;
    286 	ptm_ptyfspty.arg = NULL;
    287 
    288 	/*
    289 	 * Finally, throw away the ptyfsmount structure
    290 	 */
    291 	free(mp->mnt_data, M_UFSMNT);
    292 	mp->mnt_data = 0;
    293 	ptyfs_count--;
    294 
    295 	return 0;
    296 }
    297 
    298 int
    299 ptyfs_root(struct mount *mp, struct vnode **vpp)
    300 {
    301 	/* setup "." */
    302 	return ptyfs_allocvp(mp, vpp, PTYFSroot, 0, NULL);
    303 }
    304 
    305 /*ARGSUSED*/
    306 int
    307 ptyfs_quotactl(struct mount *mp, int cmd, uid_t uid,
    308     void *arg, struct lwp *p)
    309 {
    310 	return EOPNOTSUPP;
    311 }
    312 
    313 /*ARGSUSED*/
    314 int
    315 ptyfs_statvfs(struct mount *mp, struct statvfs *sbp, struct lwp *p)
    316 {
    317 	sbp->f_bsize = DEV_BSIZE;
    318 	sbp->f_frsize = DEV_BSIZE;
    319 	sbp->f_iosize = DEV_BSIZE;
    320 	sbp->f_blocks = 2;		/* 1K to keep df happy */
    321 	sbp->f_bfree = 0;
    322 	sbp->f_bavail = 0;
    323 	sbp->f_bresvd = 0;
    324 	sbp->f_files = 1024;	/* XXX lie */
    325 	sbp->f_ffree = 128;	/* XXX lie */
    326 	sbp->f_favail = 128;	/* XXX lie */
    327 	sbp->f_fresvd = 0;
    328 	sbp->f_namemax = MAXNAMLEN;
    329 	copy_statvfs_info(sbp, mp);
    330 	return 0;
    331 }
    332 
    333 /*ARGSUSED*/
    334 int
    335 ptyfs_sync(struct mount *mp, int waitfor,
    336     kauth_cred_t uc, struct lwp *p)
    337 {
    338 	return 0;
    339 }
    340 
    341 /*
    342  * Kernfs flat namespace lookup.
    343  * Currently unsupported.
    344  */
    345 /*ARGSUSED*/
    346 int
    347 ptyfs_vget(struct mount *mp, ino_t ino,
    348     struct vnode **vpp)
    349 {
    350 	return EOPNOTSUPP;
    351 }
    352 
    353 SYSCTL_SETUP(sysctl_vfs_ptyfs_setup, "sysctl vfs.ptyfs subtree setup")
    354 {
    355 
    356 	sysctl_createv(clog, 0, NULL, NULL,
    357 		       CTLFLAG_PERMANENT,
    358 		       CTLTYPE_NODE, "vfs", NULL,
    359 		       NULL, 0, NULL, 0,
    360 		       CTL_VFS, CTL_EOL);
    361 	sysctl_createv(clog, 0, NULL, NULL,
    362 		       CTLFLAG_PERMANENT,
    363 		       CTLTYPE_NODE, "ptyfs",
    364 		       SYSCTL_DESCR("Pty file system"),
    365 		       NULL, 0, NULL, 0,
    366 		       CTL_VFS, 23, CTL_EOL);
    367 	/*
    368 	 * XXX the "23" above could be dynamic, thereby eliminating
    369 	 * one more instance of the "number to vfs" mapping problem,
    370 	 * but "23" is the order as taken from sys/mount.h
    371 	 */
    372 }
    373 
    374 
    375 extern const struct vnodeopv_desc ptyfs_vnodeop_opv_desc;
    376 
    377 const struct vnodeopv_desc * const ptyfs_vnodeopv_descs[] = {
    378 	&ptyfs_vnodeop_opv_desc,
    379 	NULL,
    380 };
    381 
    382 struct vfsops ptyfs_vfsops = {
    383 	MOUNT_PTYFS,
    384 	sizeof (struct ptyfs_args),
    385 	ptyfs_mount,
    386 	ptyfs_start,
    387 	ptyfs_unmount,
    388 	ptyfs_root,
    389 	ptyfs_quotactl,
    390 	ptyfs_statvfs,
    391 	ptyfs_sync,
    392 	ptyfs_vget,
    393 	(void *)eopnotsupp,		/* vfs_fhtovp */
    394 	(void *)eopnotsupp,		/* vfs_vptofp */
    395 	ptyfs_init,
    396 	ptyfs_reinit,
    397 	ptyfs_done,
    398 	NULL,				/* vfs_mountroot */
    399 	(int (*)(struct mount *, struct vnode *, struct timespec *))eopnotsupp,
    400 	(int (*)(struct mount *, int, struct vnode *, int, const char *,
    401 	    struct lwp *))eopnotsupp,
    402 	(void *)eopnotsupp,		/* vfs_suspendctl */
    403 	ptyfs_vnodeopv_descs,
    404 	0,
    405 	{ NULL, NULL },
    406 };
    407 VFS_ATTACH(ptyfs_vfsops);
    408