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ptyfs_vfsops.c revision 1.48 
      1 /*	$NetBSD: ptyfs_vfsops.c,v 1.48 2014/03/27 17:31:56 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 1.48 2014/03/27 17:31:56 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 mount *, struct lwp *, struct vnode **,
     76     dev_t, char);
     77 static int ptyfs__makename(struct mount *, struct lwp *, char *, size_t,
     78     dev_t, char);
     79 static void ptyfs__getvattr(struct mount *, 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 
    105 	rv = mp->mnt_stat.f_mntonname;
    106 	if (cwdi->cwdi_rdir == NULL)
    107 		return rv;
    108 
    109 	buf = malloc(MAXBUF, M_TEMP, M_WAITOK);
    110 	bp = buf + MAXBUF;
    111 	*--bp = '\0';
    112 	error = getcwd_common(mp->mnt_vnodecovered, cwdi->cwdi_rdir, &bp,
    113 	    buf, MAXBUF / 2, 0, l);
    114 	if (error) {	/* Mount point is out of rdir */
    115 		rv = NULL;
    116 		goto out;
    117 	}
    118 
    119 	len = strlen(bp);
    120 	if (len < sizeof(mp->mnt_stat.f_mntonname))	/* XXX */
    121 		rv += strlen(rv) - len;
    122 out:
    123 	free(buf, M_TEMP);
    124 	return rv;
    125 }
    126 
    127 static int
    128 ptyfs__makename(struct mount *mp, struct lwp *l, char *tbuf, size_t bufsiz,
    129     dev_t dev, char ms)
    130 {
    131 	size_t len;
    132 	const char *np;
    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 		np = ptyfs__getpath(l, mp);
    141 		if (np == NULL)
    142 			return EOPNOTSUPP;
    143 		len = snprintf(tbuf, bufsiz, "%s/%llu", np,
    144 			(unsigned long long)minor(dev));
    145 		break;
    146 	default:
    147 		return EINVAL;
    148 	}
    149 
    150 	return len >= bufsiz ? ENOSPC : 0;
    151 }
    152 
    153 
    154 static int
    155 /*ARGSUSED*/
    156 ptyfs__allocvp(struct mount *mp, struct lwp *l, struct vnode **vpp,
    157     dev_t dev, char ms)
    158 {
    159 	ptyfstype type;
    160 
    161 	switch (ms) {
    162 	case 'p':
    163 		type = PTYFSptc;
    164 		break;
    165 	case 't':
    166 		type = PTYFSpts;
    167 		break;
    168 	default:
    169 		return EINVAL;
    170 	}
    171 
    172 	return ptyfs_allocvp(mp, vpp, type, minor(dev), l);
    173 }
    174 
    175 
    176 static void
    177 ptyfs__getvattr(struct mount *mp, struct lwp *l, struct vattr *vattr)
    178 {
    179 	struct ptyfsmount *pmnt = VFSTOPTY(mp);
    180 	vattr_null(vattr);
    181 	/* get real uid */
    182 	vattr->va_uid = kauth_cred_getuid(l->l_cred);
    183 	vattr->va_gid = pmnt->pmnt_gid;
    184 	vattr->va_mode = pmnt->pmnt_mode;
    185 }
    186 
    187 
    188 void
    189 ptyfs_init(void)
    190 {
    191 
    192 	malloc_type_attach(M_PTYFSMNT);
    193 	malloc_type_attach(M_PTYFSTMP);
    194 	ptyfs_hashinit();
    195 }
    196 
    197 void
    198 ptyfs_reinit(void)
    199 {
    200 	ptyfs_hashreinit();
    201 }
    202 
    203 void
    204 ptyfs_done(void)
    205 {
    206 
    207 	ptyfs_hashdone();
    208 	malloc_type_detach(M_PTYFSTMP);
    209 	malloc_type_detach(M_PTYFSMNT);
    210 }
    211 
    212 #define OSIZE sizeof(struct { int f; gid_t g; mode_t m; })
    213 /*
    214  * Mount the Pseudo tty params filesystem
    215  */
    216 int
    217 ptyfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
    218 {
    219 	struct lwp *l = curlwp;
    220 	int error = 0;
    221 	struct ptyfsmount *pmnt;
    222 	struct ptyfs_args *args = data;
    223 
    224 	if (*data_len != sizeof *args && *data_len != OSIZE)
    225 		return EINVAL;
    226 
    227 	if (UIO_MX & (UIO_MX - 1)) {
    228 		log(LOG_ERR, "ptyfs: invalid directory entry size");
    229 		return EINVAL;
    230 	}
    231 
    232 	if (mp->mnt_flag & MNT_GETARGS) {
    233 		pmnt = VFSTOPTY(mp);
    234 		if (pmnt == NULL)
    235 			return EIO;
    236 		args->mode = pmnt->pmnt_mode;
    237 		args->gid = pmnt->pmnt_gid;
    238 		if (args->version >= PTYFS_ARGSVERSION) {
    239 			args->flags = pmnt->pmnt_flags;
    240 			*data_len = sizeof *args;
    241 		} else {
    242 			*data_len = OSIZE;
    243 		}
    244 		return 0;
    245 	}
    246 
    247 #if 0
    248 	/* Don't allow more than one mount */
    249 	if (ptyfs_count)
    250 		return EBUSY;
    251 #endif
    252 
    253 	if (mp->mnt_flag & MNT_UPDATE)
    254 		return EOPNOTSUPP;
    255 
    256 	if (args->version > PTYFS_ARGSVERSION)
    257 		return EINVAL;
    258 
    259 	pmnt = malloc(sizeof(struct ptyfsmount), M_PTYFSMNT, M_WAITOK);
    260 
    261 	mp->mnt_data = pmnt;
    262 	pmnt->pmnt_gid = args->gid;
    263 	pmnt->pmnt_mode = args->mode;
    264 	if (args->version >= PTYFS_ARGSVERSION)
    265 		pmnt->pmnt_flags = args->flags;
    266 	else
    267 		pmnt->pmnt_flags = 0;
    268 	mp->mnt_flag |= MNT_LOCAL;
    269 	vfs_getnewfsid(mp);
    270 
    271 	if ((error = set_statvfs_info(path, UIO_USERSPACE, "ptyfs",
    272 	    UIO_SYSSPACE, mp->mnt_op->vfs_name, mp, l)) != 0) {
    273 		free(pmnt, M_PTYFSMNT);
    274 		return error;
    275 	}
    276 
    277 	/* Point pty access to us */
    278 	if (ptyfs_count == 0) {
    279 		ptm_ptyfspty.arg = mp;
    280 		ptyfs_save_ptm = pty_sethandler(&ptm_ptyfspty);
    281 	}
    282 	ptyfs_count++;
    283 	return 0;
    284 }
    285 
    286 /*ARGSUSED*/
    287 int
    288 ptyfs_start(struct mount *mp, int flags)
    289 {
    290 	return 0;
    291 }
    292 
    293 /*ARGSUSED*/
    294 int
    295 ptyfs_unmount(struct mount *mp, int mntflags)
    296 {
    297 	int error;
    298 	int flags = 0;
    299 
    300 	if (mntflags & MNT_FORCE)
    301 		flags |= FORCECLOSE;
    302 
    303 	if ((error = vflush(mp, 0, flags)) != 0)
    304 		return error;
    305 
    306 	ptyfs_count--;
    307 	if (ptyfs_count == 0) {
    308 		/* Restore where pty access was pointing */
    309 		(void)pty_sethandler(ptyfs_save_ptm);
    310 		ptyfs_save_ptm = NULL;
    311 		ptm_ptyfspty.arg = NULL;
    312 	}
    313 
    314 	/*
    315 	 * Finally, throw away the ptyfsmount structure
    316 	 */
    317 	free(mp->mnt_data, M_PTYFSMNT);
    318 	mp->mnt_data = NULL;
    319 
    320 	return 0;
    321 }
    322 
    323 int
    324 ptyfs_root(struct mount *mp, struct vnode **vpp)
    325 {
    326 	/* setup "." */
    327 	return ptyfs_allocvp(mp, vpp, PTYFSroot, 0, NULL);
    328 }
    329 
    330 /*ARGSUSED*/
    331 int
    332 ptyfs_sync(struct mount *mp, int waitfor,
    333     kauth_cred_t uc)
    334 {
    335 	return 0;
    336 }
    337 
    338 /*
    339  * Kernfs flat namespace lookup.
    340  * Currently unsupported.
    341  */
    342 /*ARGSUSED*/
    343 int
    344 ptyfs_vget(struct mount *mp, ino_t ino,
    345     struct vnode **vpp)
    346 {
    347 	return EOPNOTSUPP;
    348 }
    349 
    350 extern const struct vnodeopv_desc ptyfs_vnodeop_opv_desc;
    351 
    352 const struct vnodeopv_desc * const ptyfs_vnodeopv_descs[] = {
    353 	&ptyfs_vnodeop_opv_desc,
    354 	NULL,
    355 };
    356 
    357 struct vfsops ptyfs_vfsops = {
    358 	.vfs_name = MOUNT_PTYFS,
    359 	.vfs_min_mount_data = sizeof (struct ptyfs_args),
    360 	.vfs_mount = ptyfs_mount,
    361 	.vfs_start = ptyfs_start,
    362 	.vfs_unmount = ptyfs_unmount,
    363 	.vfs_root = ptyfs_root,
    364 	.vfs_quotactl = (void *)eopnotsupp,
    365 	.vfs_statvfs = genfs_statvfs,
    366 	.vfs_sync = ptyfs_sync,
    367 	.vfs_vget = ptyfs_vget,
    368 	.vfs_fhtovp = (void *)eopnotsupp,
    369 	.vfs_vptofh = (void *)eopnotsupp,
    370 	.vfs_init = ptyfs_init,
    371 	.vfs_reinit = ptyfs_reinit,
    372 	.vfs_done = ptyfs_done,
    373 	.vfs_snapshot = (void *)eopnotsupp,
    374 	.vfs_extattrctl = (void *)eopnotsupp,
    375 	.vfs_suspendctl = (void *)eopnotsupp,
    376 	.vfs_renamelock_enter = genfs_renamelock_enter,
    377 	.vfs_renamelock_exit = genfs_renamelock_exit,
    378 	.vfs_fsync = (void *)eopnotsupp,
    379 	.vfs_opv_descs = ptyfs_vnodeopv_descs
    380 };
    381 
    382 static int
    383 ptyfs_modcmd(modcmd_t cmd, void *arg)
    384 {
    385 	int error;
    386 
    387 	switch (cmd) {
    388 	case MODULE_CMD_INIT:
    389 		error = vfs_attach(&ptyfs_vfsops);
    390 		if (error != 0)
    391 			break;
    392 		sysctl_createv(&ptyfs_sysctl_log, 0, NULL, NULL,
    393 			       CTLFLAG_PERMANENT,
    394 			       CTLTYPE_NODE, "ptyfs",
    395 			       SYSCTL_DESCR("Pty file system"),
    396 			       NULL, 0, NULL, 0,
    397 			       CTL_VFS, 23, CTL_EOL);
    398 		/*
    399 		 * XXX the "23" above could be dynamic, thereby eliminating
    400 		 * one more instance of the "number to vfs" mapping problem,
    401 		 * but "23" is the order as taken from sys/mount.h
    402 		 */
    403 		break;
    404 	case MODULE_CMD_FINI:
    405 		error = vfs_detach(&ptyfs_vfsops);
    406 		if (error != 0)
    407 			break;
    408 		sysctl_teardown(&ptyfs_sysctl_log);
    409 		break;
    410 	default:
    411 		error = ENOTTY;
    412 		break;
    413 	}
    414 
    415 	return (error);
    416 }
    417