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ptyfs_vfsops.c revision 1.42.12.1 
      1 /*	$NetBSD: ptyfs_vfsops.c,v 1.42.12.1 2012/10/30 17:22:24 yamt 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 1.42.12.1 2012/10/30 17:22:24 yamt 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 
    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(cwdi->cwdi_rdir, rootvnode, &bp,
    113 	    buf, MAXBUF / 2, 0, l);
    114 	if (error)	/* XXX */
    115 		goto out;
    116 
    117 	len = strlen(bp);
    118 	if (len < sizeof(mp->mnt_stat.f_mntonname))	/* XXX */
    119 		rv += len;
    120 out:
    121 	free(buf, M_TEMP);
    122 	return rv;
    123 }
    124 
    125 static int
    126 ptyfs__makename(struct ptm_pty *pt, struct lwp *l, char *tbuf, size_t bufsiz,
    127     dev_t dev, char ms)
    128 {
    129 	struct mount *mp = pt->arg;
    130 	size_t len;
    131 
    132 	switch (ms) {
    133 	case 'p':
    134 		/* We don't provide access to the master, should we? */
    135 		len = snprintf(tbuf, bufsiz, "/dev/null");
    136 		break;
    137 	case 't':
    138 		len = snprintf(tbuf, bufsiz, "%s/%llu", ptyfs__getpath(l, mp),
    139 		    (unsigned long long)minor(dev));
    140 		break;
    141 	default:
    142 		return EINVAL;
    143 	}
    144 
    145 	return len >= bufsiz ? ENOSPC : 0;
    146 }
    147 
    148 
    149 static int
    150 /*ARGSUSED*/
    151 ptyfs__allocvp(struct ptm_pty *pt, struct lwp *l, struct vnode **vpp,
    152     dev_t dev, char ms)
    153 {
    154 	struct mount *mp = pt->arg;
    155 	ptyfstype type;
    156 
    157 	switch (ms) {
    158 	case 'p':
    159 		type = PTYFSptc;
    160 		break;
    161 	case 't':
    162 		type = PTYFSpts;
    163 		break;
    164 	default:
    165 		return EINVAL;
    166 	}
    167 
    168 	return ptyfs_allocvp(mp, vpp, type, minor(dev), l);
    169 }
    170 
    171 
    172 static void
    173 ptyfs__getvattr(struct ptm_pty *pt, struct lwp *l, struct vattr *vattr)
    174 {
    175 	struct mount *mp = pt->arg;
    176 	struct ptyfsmount *pmnt = VFSTOPTY(mp);
    177 	vattr_null(vattr);
    178 	/* get real uid */
    179 	vattr->va_uid = kauth_cred_getuid(l->l_cred);
    180 	vattr->va_gid = pmnt->pmnt_gid;
    181 	vattr->va_mode = pmnt->pmnt_mode;
    182 }
    183 
    184 
    185 void
    186 ptyfs_init(void)
    187 {
    188 
    189 	malloc_type_attach(M_PTYFSMNT);
    190 	malloc_type_attach(M_PTYFSTMP);
    191 	ptyfs_hashinit();
    192 }
    193 
    194 void
    195 ptyfs_reinit(void)
    196 {
    197 	ptyfs_hashreinit();
    198 }
    199 
    200 void
    201 ptyfs_done(void)
    202 {
    203 
    204 	ptyfs_hashdone();
    205 	malloc_type_detach(M_PTYFSTMP);
    206 	malloc_type_detach(M_PTYFSMNT);
    207 }
    208 
    209 #define OSIZE sizeof(struct { int f; gid_t g; mode_t m; })
    210 /*
    211  * Mount the Pseudo tty params filesystem
    212  */
    213 int
    214 ptyfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
    215 {
    216 	struct lwp *l = curlwp;
    217 	int error = 0;
    218 	struct ptyfsmount *pmnt;
    219 	struct ptyfs_args *args = data;
    220 
    221 	if (*data_len != sizeof *args && *data_len != OSIZE)
    222 		return EINVAL;
    223 
    224 	if (UIO_MX & (UIO_MX - 1)) {
    225 		log(LOG_ERR, "ptyfs: invalid directory entry size");
    226 		return EINVAL;
    227 	}
    228 
    229 	if (mp->mnt_flag & MNT_GETARGS) {
    230 		pmnt = VFSTOPTY(mp);
    231 		if (pmnt == NULL)
    232 			return EIO;
    233 		args->mode = pmnt->pmnt_mode;
    234 		args->gid = pmnt->pmnt_gid;
    235 		if (args->version >= PTYFS_ARGSVERSION) {
    236 			args->flags = pmnt->pmnt_flags;
    237 			*data_len = sizeof *args;
    238 		} else {
    239 			*data_len = OSIZE;
    240 		}
    241 		return 0;
    242 	}
    243 
    244 #if 0
    245 	/* Don't allow more than one mount */
    246 	if (ptyfs_count)
    247 		return EBUSY;
    248 #endif
    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 	if (ptyfs_count == 0) {
    276 		ptm_ptyfspty.arg = mp;
    277 		ptyfs_save_ptm = pty_sethandler(&ptm_ptyfspty);
    278 	}
    279 	ptyfs_count++;
    280 	return 0;
    281 }
    282 
    283 /*ARGSUSED*/
    284 int
    285 ptyfs_start(struct mount *mp, int flags)
    286 {
    287 	return 0;
    288 }
    289 
    290 /*ARGSUSED*/
    291 int
    292 ptyfs_unmount(struct mount *mp, int mntflags)
    293 {
    294 	int error;
    295 	int flags = 0;
    296 
    297 	if (mntflags & MNT_FORCE)
    298 		flags |= FORCECLOSE;
    299 
    300 	if ((error = vflush(mp, 0, flags)) != 0)
    301 		return error;
    302 
    303 	ptyfs_count--;
    304 	if (ptyfs_count == 0) {
    305 		/* Restore where pty access was pointing */
    306 		(void)pty_sethandler(ptyfs_save_ptm);
    307 		ptyfs_save_ptm = NULL;
    308 		ptm_ptyfspty.arg = NULL;
    309 	}
    310 
    311 	/*
    312 	 * Finally, throw away the ptyfsmount structure
    313 	 */
    314 	free(mp->mnt_data, M_PTYFSMNT);
    315 	mp->mnt_data = NULL;
    316 
    317 	return 0;
    318 }
    319 
    320 int
    321 ptyfs_root(struct mount *mp, struct vnode **vpp)
    322 {
    323 	/* setup "." */
    324 	return ptyfs_allocvp(mp, vpp, PTYFSroot, 0, NULL);
    325 }
    326 
    327 /*ARGSUSED*/
    328 int
    329 ptyfs_sync(struct mount *mp, int waitfor,
    330     kauth_cred_t uc)
    331 {
    332 	return 0;
    333 }
    334 
    335 /*
    336  * Kernfs flat namespace lookup.
    337  * Currently unsupported.
    338  */
    339 /*ARGSUSED*/
    340 int
    341 ptyfs_vget(struct mount *mp, ino_t ino,
    342     struct vnode **vpp)
    343 {
    344 	return EOPNOTSUPP;
    345 }
    346 
    347 extern const struct vnodeopv_desc ptyfs_vnodeop_opv_desc;
    348 
    349 const struct vnodeopv_desc * const ptyfs_vnodeopv_descs[] = {
    350 	&ptyfs_vnodeop_opv_desc,
    351 	NULL,
    352 };
    353 
    354 struct vfsops ptyfs_vfsops = {
    355 	MOUNT_PTYFS,
    356 	sizeof (struct ptyfs_args),
    357 	ptyfs_mount,
    358 	ptyfs_start,
    359 	ptyfs_unmount,
    360 	ptyfs_root,
    361 	(void *)eopnotsupp,		/* vfs_quotactl */
    362 	genfs_statvfs,
    363 	ptyfs_sync,
    364 	ptyfs_vget,
    365 	(void *)eopnotsupp,		/* vfs_fhtovp */
    366 	(void *)eopnotsupp,		/* vfs_vptofp */
    367 	ptyfs_init,
    368 	ptyfs_reinit,
    369 	ptyfs_done,
    370 	NULL,				/* vfs_mountroot */
    371 	(void *)eopnotsupp,
    372 	(void *)eopnotsupp,
    373 	(void *)eopnotsupp,		/* vfs_suspendctl */
    374 	genfs_renamelock_enter,
    375 	genfs_renamelock_exit,
    376 	(void *)eopnotsupp,
    377 	ptyfs_vnodeopv_descs,
    378 	0,
    379 	{ NULL, NULL },
    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, "vfs", NULL,
    395 			       NULL, 0, NULL, 0,
    396 			       CTL_VFS, CTL_EOL);
    397 		sysctl_createv(&ptyfs_sysctl_log, 0, NULL, NULL,
    398 			       CTLFLAG_PERMANENT,
    399 			       CTLTYPE_NODE, "ptyfs",
    400 			       SYSCTL_DESCR("Pty file system"),
    401 			       NULL, 0, NULL, 0,
    402 			       CTL_VFS, 23, CTL_EOL);
    403 		/*
    404 		 * XXX the "23" above could be dynamic, thereby eliminating
    405 		 * one more instance of the "number to vfs" mapping problem,
    406 		 * but "23" is the order as taken from sys/mount.h
    407 		 */
    408 		break;
    409 	case MODULE_CMD_FINI:
    410 		error = vfs_detach(&ptyfs_vfsops);
    411 		if (error != 0)
    412 			break;
    413 		sysctl_teardown(&ptyfs_sysctl_log);
    414 		break;
    415 	default:
    416 		error = ENOTTY;
    417 		break;
    418 	}
    419 
    420 	return (error);
    421 }
    422