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ptyfs_vfsops.c revision 1.35.2.1 
      1 /*	$NetBSD: ptyfs_vfsops.c,v 1.35.2.1 2008/07/03 18:38:11 simonb 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 1.35.2.1 2008/07/03 18:38:11 simonb 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/%d", ptyfs__getpath(l, mp),
    139 		    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 /*
    210  * Mount the Pseudo tty params filesystem
    211  */
    212 int
    213 ptyfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
    214 {
    215 	struct lwp *l = curlwp;
    216 	int error = 0;
    217 	struct ptyfsmount *pmnt;
    218 	struct ptyfs_args *args = data;
    219 
    220 	if (*data_len < sizeof *args)
    221 		return EINVAL;
    222 
    223 	if (UIO_MX & (UIO_MX - 1)) {
    224 		log(LOG_ERR, "ptyfs: invalid directory entry size");
    225 		return EINVAL;
    226 	}
    227 
    228 	if (mp->mnt_flag & MNT_GETARGS) {
    229 		pmnt = VFSTOPTY(mp);
    230 		if (pmnt == NULL)
    231 			return EIO;
    232 		args->version = PTYFS_ARGSVERSION;
    233 		args->mode = pmnt->pmnt_mode;
    234 		args->gid = pmnt->pmnt_gid;
    235 		*data_len = sizeof *args;
    236 		return 0;
    237 	}
    238 
    239 	/* Don't allow more than one mount */
    240 	if (ptyfs_count)
    241 		return EBUSY;
    242 
    243 	if (mp->mnt_flag & MNT_UPDATE)
    244 		return EOPNOTSUPP;
    245 
    246 	if (args->version != PTYFS_ARGSVERSION)
    247 		return EINVAL;
    248 
    249 	pmnt = malloc(sizeof(struct ptyfsmount), M_PTYFSMNT, M_WAITOK);
    250 
    251 	mp->mnt_data = pmnt;
    252 	pmnt->pmnt_gid = args->gid;
    253 	pmnt->pmnt_mode = args->mode;
    254 	mp->mnt_flag |= MNT_LOCAL;
    255 	vfs_getnewfsid(mp);
    256 
    257 	if ((error = set_statvfs_info(path, UIO_USERSPACE, "ptyfs",
    258 	    UIO_SYSSPACE, mp->mnt_op->vfs_name, mp, l)) != 0) {
    259 		free(pmnt, M_PTYFSMNT);
    260 		return error;
    261 	}
    262 
    263 	/* Point pty access to us */
    264 
    265 	ptm_ptyfspty.arg = mp;
    266 	ptyfs_save_ptm = pty_sethandler(&ptm_ptyfspty);
    267 	ptyfs_count++;
    268 	return 0;
    269 }
    270 
    271 /*ARGSUSED*/
    272 int
    273 ptyfs_start(struct mount *mp, int flags)
    274 {
    275 	return 0;
    276 }
    277 
    278 /*ARGSUSED*/
    279 int
    280 ptyfs_unmount(struct mount *mp, int mntflags)
    281 {
    282 	int error;
    283 	int flags = 0;
    284 
    285 	if (mntflags & MNT_FORCE)
    286 		flags |= FORCECLOSE;
    287 
    288 	if ((error = vflush(mp, 0, flags)) != 0)
    289 		return (error);
    290 
    291 	/* Restore where pty access was pointing */
    292 	(void)pty_sethandler(ptyfs_save_ptm);
    293 	ptyfs_save_ptm = NULL;
    294 	ptm_ptyfspty.arg = NULL;
    295 
    296 	/*
    297 	 * Finally, throw away the ptyfsmount structure
    298 	 */
    299 	free(mp->mnt_data, M_PTYFSMNT);
    300 	mp->mnt_data = NULL;
    301 	ptyfs_count--;
    302 
    303 	return 0;
    304 }
    305 
    306 int
    307 ptyfs_root(struct mount *mp, struct vnode **vpp)
    308 {
    309 	/* setup "." */
    310 	return ptyfs_allocvp(mp, vpp, PTYFSroot, 0, NULL);
    311 }
    312 
    313 /*ARGSUSED*/
    314 int
    315 ptyfs_statvfs(struct mount *mp, struct statvfs *sbp)
    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)
    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 extern const struct vnodeopv_desc ptyfs_vnodeop_opv_desc;
    354 
    355 const struct vnodeopv_desc * const ptyfs_vnodeopv_descs[] = {
    356 	&ptyfs_vnodeop_opv_desc,
    357 	NULL,
    358 };
    359 
    360 struct vfsops ptyfs_vfsops = {
    361 	MOUNT_PTYFS,
    362 	sizeof (struct ptyfs_args),
    363 	ptyfs_mount,
    364 	ptyfs_start,
    365 	ptyfs_unmount,
    366 	ptyfs_root,
    367 	(void *)eopnotsupp,		/* vfs_quotactl */
    368 	ptyfs_statvfs,
    369 	ptyfs_sync,
    370 	ptyfs_vget,
    371 	(void *)eopnotsupp,		/* vfs_fhtovp */
    372 	(void *)eopnotsupp,		/* vfs_vptofp */
    373 	ptyfs_init,
    374 	ptyfs_reinit,
    375 	ptyfs_done,
    376 	NULL,				/* vfs_mountroot */
    377 	(void *)eopnotsupp,
    378 	(void *)eopnotsupp,
    379 	(void *)eopnotsupp,		/* vfs_suspendctl */
    380 	genfs_renamelock_enter,
    381 	genfs_renamelock_exit,
    382 	(void *)eopnotsupp,
    383 	ptyfs_vnodeopv_descs,
    384 	0,
    385 	{ NULL, NULL },
    386 };
    387 
    388 static int
    389 ptyfs_modcmd(modcmd_t cmd, void *arg)
    390 {
    391 	int error;
    392 
    393 	switch (cmd) {
    394 	case MODULE_CMD_INIT:
    395 		error = vfs_attach(&ptyfs_vfsops);
    396 		if (error != 0)
    397 			break;
    398 		sysctl_createv(&ptyfs_sysctl_log, 0, NULL, NULL,
    399 			       CTLFLAG_PERMANENT,
    400 			       CTLTYPE_NODE, "vfs", NULL,
    401 			       NULL, 0, NULL, 0,
    402 			       CTL_VFS, CTL_EOL);
    403 		sysctl_createv(&ptyfs_sysctl_log, 0, NULL, NULL,
    404 			       CTLFLAG_PERMANENT,
    405 			       CTLTYPE_NODE, "ptyfs",
    406 			       SYSCTL_DESCR("Pty file system"),
    407 			       NULL, 0, NULL, 0,
    408 			       CTL_VFS, 23, CTL_EOL);
    409 		/*
    410 		 * XXX the "23" above could be dynamic, thereby eliminating
    411 		 * one more instance of the "number to vfs" mapping problem,
    412 		 * but "23" is the order as taken from sys/mount.h
    413 		 */
    414 		break;
    415 	case MODULE_CMD_FINI:
    416 		error = vfs_detach(&ptyfs_vfsops);
    417 		if (error != 0)
    418 			break;
    419 		sysctl_teardown(&ptyfs_sysctl_log);
    420 		break;
    421 	default:
    422 		error = ENOTTY;
    423 		break;
    424 	}
    425 
    426 	return (error);
    427 }
    428