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ptyfs_vfsops.c revision 1.40 
      1 /*	$NetBSD: ptyfs_vfsops.c,v 1.40 2009/03/21 01:11:53 christos 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 1.40 2009/03/21 01:11:53 christos 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 #include <sys/module.h>
     61 
     62 #include <fs/ptyfs/ptyfs.h>
     63 #include <miscfs/genfs/genfs.h>
     64 #include <miscfs/specfs/specdev.h>
     65 
     66 MODULE(MODULE_CLASS_VFS, ptyfs, NULL);
     67 
     68 MALLOC_JUSTDEFINE(M_PTYFSMNT, "ptyfs mount", "ptyfs mount structures");
     69 MALLOC_JUSTDEFINE(M_PTYFSTMP, "ptyfs temp", "ptyfs temporary structures");
     70 
     71 VFS_PROTOS(ptyfs);
     72 
     73 static struct sysctllog *ptyfs_sysctl_log;
     74 
     75 static int ptyfs__allocvp(struct ptm_pty *, struct lwp *, struct vnode **,
     76     dev_t, char);
     77 static int ptyfs__makename(struct ptm_pty *, struct lwp *, char *, size_t,
     78     dev_t, char);
     79 static void ptyfs__getvattr(struct ptm_pty *, struct lwp *, struct vattr *);
     80 
     81 /*
     82  * ptm glue: When we mount, we make ptm point to us.
     83  */
     84 struct ptm_pty *ptyfs_save_ptm;
     85 static int ptyfs_count;
     86 
     87 struct ptm_pty ptm_ptyfspty = {
     88 	ptyfs__allocvp,
     89 	ptyfs__makename,
     90 	ptyfs__getvattr,
     91 	NULL
     92 };
     93 
     94 static const char *
     95 ptyfs__getpath(struct lwp *l, const struct mount *mp)
     96 {
     97 #define MAXBUF (sizeof(mp->mnt_stat.f_mntonname) + 32)
     98 	struct cwdinfo *cwdi = l->l_proc->p_cwdi;
     99 	char *buf;
    100 	const char *rv;
    101 	size_t len;
    102 	char *bp;
    103 	int error;
    104 	struct ptyfsmount *pmnt = mp->mnt_data;
    105 
    106 	rv = mp->mnt_stat.f_mntonname;
    107 	if (cwdi->cwdi_rdir == NULL ||
    108 	    (pmnt->pmnt_flags & PTYFSMNT_CHROOT) == 0)
    109 		return rv;
    110 
    111 	buf = malloc(MAXBUF, M_TEMP, M_WAITOK);
    112 	bp = buf + MAXBUF;
    113 	*--bp = '\0';
    114 	error = getcwd_common(cwdi->cwdi_rdir, rootvnode, &bp,
    115 	    buf, MAXBUF / 2, 0, l);
    116 	if (error)	/* XXX */
    117 		goto out;
    118 
    119 	len = strlen(bp);
    120 	if (len < sizeof(mp->mnt_stat.f_mntonname))	/* XXX */
    121 		rv += len;
    122 out:
    123 	free(buf, M_TEMP);
    124 	return rv;
    125 }
    126 
    127 static int
    128 ptyfs__makename(struct ptm_pty *pt, struct lwp *l, char *tbuf, size_t bufsiz,
    129     dev_t dev, char ms)
    130 {
    131 	struct mount *mp = pt->arg;
    132 	size_t len;
    133 
    134 	switch (ms) {
    135 	case 'p':
    136 		/* We don't provide access to the master, should we? */
    137 		len = snprintf(tbuf, bufsiz, "/dev/null");
    138 		break;
    139 	case 't':
    140 		len = snprintf(tbuf, bufsiz, "%s/%llu", ptyfs__getpath(l, mp),
    141 		    (unsigned long long)minor(dev));
    142 		break;
    143 	default:
    144 		return EINVAL;
    145 	}
    146 
    147 	return len >= bufsiz ? ENOSPC : 0;
    148 }
    149 
    150 
    151 static int
    152 /*ARGSUSED*/
    153 ptyfs__allocvp(struct ptm_pty *pt, struct lwp *l, struct vnode **vpp,
    154     dev_t dev, char ms)
    155 {
    156 	struct mount *mp = pt->arg;
    157 	ptyfstype type;
    158 
    159 	switch (ms) {
    160 	case 'p':
    161 		type = PTYFSptc;
    162 		break;
    163 	case 't':
    164 		type = PTYFSpts;
    165 		break;
    166 	default:
    167 		return EINVAL;
    168 	}
    169 
    170 	return ptyfs_allocvp(mp, vpp, type, minor(dev), l);
    171 }
    172 
    173 
    174 static void
    175 ptyfs__getvattr(struct ptm_pty *pt, struct lwp *l, struct vattr *vattr)
    176 {
    177 	struct mount *mp = pt->arg;
    178 	struct ptyfsmount *pmnt = VFSTOPTY(mp);
    179 	VATTR_NULL(vattr);
    180 	/* get real uid */
    181 	vattr->va_uid = kauth_cred_getuid(l->l_cred);
    182 	vattr->va_gid = pmnt->pmnt_gid;
    183 	vattr->va_mode = pmnt->pmnt_mode;
    184 }
    185 
    186 
    187 void
    188 ptyfs_init(void)
    189 {
    190 
    191 	malloc_type_attach(M_PTYFSMNT);
    192 	malloc_type_attach(M_PTYFSTMP);
    193 	ptyfs_hashinit();
    194 }
    195 
    196 void
    197 ptyfs_reinit(void)
    198 {
    199 	ptyfs_hashreinit();
    200 }
    201 
    202 void
    203 ptyfs_done(void)
    204 {
    205 
    206 	ptyfs_hashdone();
    207 	malloc_type_detach(M_PTYFSTMP);
    208 	malloc_type_detach(M_PTYFSMNT);
    209 }
    210 
    211 #define OSIZE sizeof(struct { int f; gid_t g; mode_t m; })
    212 /*
    213  * Mount the Pseudo tty params filesystem
    214  */
    215 int
    216 ptyfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
    217 {
    218 	struct lwp *l = curlwp;
    219 	int error = 0;
    220 	struct ptyfsmount *pmnt;
    221 	struct ptyfs_args *args = data;
    222 
    223 	if (*data_len != sizeof *args && *data_len != OSIZE)
    224 		return EINVAL;
    225 
    226 	if (UIO_MX & (UIO_MX - 1)) {
    227 		log(LOG_ERR, "ptyfs: invalid directory entry size");
    228 		return EINVAL;
    229 	}
    230 
    231 	if (mp->mnt_flag & MNT_GETARGS) {
    232 		pmnt = VFSTOPTY(mp);
    233 		if (pmnt == NULL)
    234 			return EIO;
    235 		args->mode = pmnt->pmnt_mode;
    236 		args->gid = pmnt->pmnt_gid;
    237 		if (args->version >= PTYFS_ARGSVERSION) {
    238 			args->flags = pmnt->pmnt_flags;
    239 			*data_len = sizeof *args;
    240 		} else {
    241 			*data_len = OSIZE;
    242 		}
    243 		return 0;
    244 	}
    245 
    246 	/* Don't allow more than one mount */
    247 	if (ptyfs_count)
    248 		return EBUSY;
    249 
    250 	if (mp->mnt_flag & MNT_UPDATE)
    251 		return EOPNOTSUPP;
    252 
    253 	if (args->version > PTYFS_ARGSVERSION)
    254 		return EINVAL;
    255 
    256 	pmnt = malloc(sizeof(struct ptyfsmount), M_PTYFSMNT, M_WAITOK);
    257 
    258 	mp->mnt_data = pmnt;
    259 	pmnt->pmnt_gid = args->gid;
    260 	pmnt->pmnt_mode = args->mode;
    261 	if (args->version >= PTYFS_ARGSVERSION)
    262 		pmnt->pmnt_flags = args->flags;
    263 	else
    264 		pmnt->pmnt_flags = 0;
    265 	mp->mnt_flag |= MNT_LOCAL;
    266 	vfs_getnewfsid(mp);
    267 
    268 	if ((error = set_statvfs_info(path, UIO_USERSPACE, "ptyfs",
    269 	    UIO_SYSSPACE, mp->mnt_op->vfs_name, mp, l)) != 0) {
    270 		free(pmnt, M_PTYFSMNT);
    271 		return error;
    272 	}
    273 
    274 	/* Point pty access to us */
    275 
    276 	ptm_ptyfspty.arg = mp;
    277 	ptyfs_save_ptm = pty_sethandler(&ptm_ptyfspty);
    278 	ptyfs_count++;
    279 	return 0;
    280 }
    281 
    282 /*ARGSUSED*/
    283 int
    284 ptyfs_start(struct mount *mp, int flags)
    285 {
    286 	return 0;
    287 }
    288 
    289 /*ARGSUSED*/
    290 int
    291 ptyfs_unmount(struct mount *mp, int mntflags)
    292 {
    293 	int error;
    294 	int flags = 0;
    295 
    296 	if (mntflags & MNT_FORCE)
    297 		flags |= FORCECLOSE;
    298 
    299 	if ((error = vflush(mp, 0, flags)) != 0)
    300 		return (error);
    301 
    302 	/* Restore where pty access was pointing */
    303 	(void)pty_sethandler(ptyfs_save_ptm);
    304 	ptyfs_save_ptm = NULL;
    305 	ptm_ptyfspty.arg = NULL;
    306 
    307 	/*
    308 	 * Finally, throw away the ptyfsmount structure
    309 	 */
    310 	free(mp->mnt_data, M_PTYFSMNT);
    311 	mp->mnt_data = NULL;
    312 	ptyfs_count--;
    313 
    314 	return 0;
    315 }
    316 
    317 int
    318 ptyfs_root(struct mount *mp, struct vnode **vpp)
    319 {
    320 	/* setup "." */
    321 	return ptyfs_allocvp(mp, vpp, PTYFSroot, 0, NULL);
    322 }
    323 
    324 /*ARGSUSED*/
    325 int
    326 ptyfs_statvfs(struct mount *mp, struct statvfs *sbp)
    327 {
    328 	sbp->f_bsize = DEV_BSIZE;
    329 	sbp->f_frsize = DEV_BSIZE;
    330 	sbp->f_iosize = DEV_BSIZE;
    331 	sbp->f_blocks = 2;		/* 1K to keep df happy */
    332 	sbp->f_bfree = 0;
    333 	sbp->f_bavail = 0;
    334 	sbp->f_bresvd = 0;
    335 	sbp->f_files = 1024;	/* XXX lie */
    336 	sbp->f_ffree = 128;	/* XXX lie */
    337 	sbp->f_favail = 128;	/* XXX lie */
    338 	sbp->f_fresvd = 0;
    339 	sbp->f_namemax = MAXNAMLEN;
    340 	copy_statvfs_info(sbp, mp);
    341 	return 0;
    342 }
    343 
    344 /*ARGSUSED*/
    345 int
    346 ptyfs_sync(struct mount *mp, int waitfor,
    347     kauth_cred_t uc)
    348 {
    349 	return 0;
    350 }
    351 
    352 /*
    353  * Kernfs flat namespace lookup.
    354  * Currently unsupported.
    355  */
    356 /*ARGSUSED*/
    357 int
    358 ptyfs_vget(struct mount *mp, ino_t ino,
    359     struct vnode **vpp)
    360 {
    361 	return EOPNOTSUPP;
    362 }
    363 
    364 extern const struct vnodeopv_desc ptyfs_vnodeop_opv_desc;
    365 
    366 const struct vnodeopv_desc * const ptyfs_vnodeopv_descs[] = {
    367 	&ptyfs_vnodeop_opv_desc,
    368 	NULL,
    369 };
    370 
    371 struct vfsops ptyfs_vfsops = {
    372 	MOUNT_PTYFS,
    373 	sizeof (struct ptyfs_args),
    374 	ptyfs_mount,
    375 	ptyfs_start,
    376 	ptyfs_unmount,
    377 	ptyfs_root,
    378 	(void *)eopnotsupp,		/* vfs_quotactl */
    379 	ptyfs_statvfs,
    380 	ptyfs_sync,
    381 	ptyfs_vget,
    382 	(void *)eopnotsupp,		/* vfs_fhtovp */
    383 	(void *)eopnotsupp,		/* vfs_vptofp */
    384 	ptyfs_init,
    385 	ptyfs_reinit,
    386 	ptyfs_done,
    387 	NULL,				/* vfs_mountroot */
    388 	(void *)eopnotsupp,
    389 	(void *)eopnotsupp,
    390 	(void *)eopnotsupp,		/* vfs_suspendctl */
    391 	genfs_renamelock_enter,
    392 	genfs_renamelock_exit,
    393 	(void *)eopnotsupp,
    394 	ptyfs_vnodeopv_descs,
    395 	0,
    396 	{ NULL, NULL },
    397 };
    398 
    399 static int
    400 ptyfs_modcmd(modcmd_t cmd, void *arg)
    401 {
    402 	int error;
    403 
    404 	switch (cmd) {
    405 	case MODULE_CMD_INIT:
    406 		error = vfs_attach(&ptyfs_vfsops);
    407 		if (error != 0)
    408 			break;
    409 		sysctl_createv(&ptyfs_sysctl_log, 0, NULL, NULL,
    410 			       CTLFLAG_PERMANENT,
    411 			       CTLTYPE_NODE, "vfs", NULL,
    412 			       NULL, 0, NULL, 0,
    413 			       CTL_VFS, CTL_EOL);
    414 		sysctl_createv(&ptyfs_sysctl_log, 0, NULL, NULL,
    415 			       CTLFLAG_PERMANENT,
    416 			       CTLTYPE_NODE, "ptyfs",
    417 			       SYSCTL_DESCR("Pty file system"),
    418 			       NULL, 0, NULL, 0,
    419 			       CTL_VFS, 23, CTL_EOL);
    420 		/*
    421 		 * XXX the "23" above could be dynamic, thereby eliminating
    422 		 * one more instance of the "number to vfs" mapping problem,
    423 		 * but "23" is the order as taken from sys/mount.h
    424 		 */
    425 		break;
    426 	case MODULE_CMD_FINI:
    427 		error = vfs_detach(&ptyfs_vfsops);
    428 		if (error != 0)
    429 			break;
    430 		sysctl_teardown(&ptyfs_sysctl_log);
    431 		break;
    432 	default:
    433 		error = ENOTTY;
    434 		break;
    435 	}
    436 
    437 	return (error);
    438 }
    439