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ptyfs_vfsops.c revision 1.35 
      1 /*	$NetBSD: ptyfs_vfsops.c,v 1.35 2008/05/13 08:31:12 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 2008/05/13 08:31:12 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 int ptyfs__allocvp(struct ptm_pty *, struct lwp *, struct vnode **,
     74     dev_t, char);
     75 static int ptyfs__makename(struct ptm_pty *, struct lwp *, char *, size_t,
     76     dev_t, char);
     77 static void ptyfs__getvattr(struct ptm_pty *, struct lwp *, struct vattr *);
     78 
     79 /*
     80  * ptm glue: When we mount, we make ptm point to us.
     81  */
     82 struct ptm_pty *ptyfs_save_ptm;
     83 static int ptyfs_count;
     84 
     85 struct ptm_pty ptm_ptyfspty = {
     86 	ptyfs__allocvp,
     87 	ptyfs__makename,
     88 	ptyfs__getvattr,
     89 	NULL
     90 };
     91 
     92 static const char *
     93 ptyfs__getpath(struct lwp *l, const struct mount *mp)
     94 {
     95 #define MAXBUF (sizeof(mp->mnt_stat.f_mntonname) + 32)
     96 	struct cwdinfo *cwdi = l->l_proc->p_cwdi;
     97 	char *buf;
     98 	const char *rv;
     99 	size_t len;
    100 	char *bp;
    101 	int error;
    102 
    103 	rv = mp->mnt_stat.f_mntonname;
    104 	if (cwdi->cwdi_rdir == NULL)
    105 		return rv;
    106 
    107 	buf = malloc(MAXBUF, M_TEMP, M_WAITOK);
    108 	bp = buf + MAXBUF;
    109 	*--bp = '\0';
    110 	error = getcwd_common(cwdi->cwdi_rdir, rootvnode, &bp,
    111 	    buf, MAXBUF / 2, 0, l);
    112 	if (error)	/* XXX */
    113 		goto out;
    114 
    115 	len = strlen(bp);
    116 	if (len < sizeof(mp->mnt_stat.f_mntonname))	/* XXX */
    117 		rv += len;
    118 out:
    119 	free(buf, M_TEMP);
    120 	return rv;
    121 }
    122 
    123 static int
    124 ptyfs__makename(struct ptm_pty *pt, struct lwp *l, char *tbuf, size_t bufsiz,
    125     dev_t dev, char ms)
    126 {
    127 	struct mount *mp = pt->arg;
    128 	size_t len;
    129 
    130 	switch (ms) {
    131 	case 'p':
    132 		/* We don't provide access to the master, should we? */
    133 		len = snprintf(tbuf, bufsiz, "/dev/null");
    134 		break;
    135 	case 't':
    136 		len = snprintf(tbuf, bufsiz, "%s/%d", ptyfs__getpath(l, mp),
    137 		    minor(dev));
    138 		break;
    139 	default:
    140 		return EINVAL;
    141 	}
    142 
    143 	return len >= bufsiz ? ENOSPC : 0;
    144 }
    145 
    146 
    147 static int
    148 /*ARGSUSED*/
    149 ptyfs__allocvp(struct ptm_pty *pt, struct lwp *l, struct vnode **vpp,
    150     dev_t dev, char ms)
    151 {
    152 	struct mount *mp = pt->arg;
    153 	ptyfstype type;
    154 
    155 	switch (ms) {
    156 	case 'p':
    157 		type = PTYFSptc;
    158 		break;
    159 	case 't':
    160 		type = PTYFSpts;
    161 		break;
    162 	default:
    163 		return EINVAL;
    164 	}
    165 
    166 	return ptyfs_allocvp(mp, vpp, type, minor(dev), l);
    167 }
    168 
    169 
    170 static void
    171 ptyfs__getvattr(struct ptm_pty *pt, struct lwp *l, struct vattr *vattr)
    172 {
    173 	struct mount *mp = pt->arg;
    174 	struct ptyfsmount *pmnt = VFSTOPTY(mp);
    175 	VATTR_NULL(vattr);
    176 	/* get real uid */
    177 	vattr->va_uid = kauth_cred_getuid(l->l_cred);
    178 	vattr->va_gid = pmnt->pmnt_gid;
    179 	vattr->va_mode = pmnt->pmnt_mode;
    180 }
    181 
    182 
    183 void
    184 ptyfs_init(void)
    185 {
    186 
    187 	malloc_type_attach(M_PTYFSMNT);
    188 	malloc_type_attach(M_PTYFSTMP);
    189 	ptyfs_hashinit();
    190 }
    191 
    192 void
    193 ptyfs_reinit(void)
    194 {
    195 	ptyfs_hashreinit();
    196 }
    197 
    198 void
    199 ptyfs_done(void)
    200 {
    201 
    202 	ptyfs_hashdone();
    203 	malloc_type_detach(M_PTYFSTMP);
    204 	malloc_type_detach(M_PTYFSMNT);
    205 }
    206 
    207 /*
    208  * Mount the Pseudo tty params filesystem
    209  */
    210 int
    211 ptyfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
    212 {
    213 	struct lwp *l = curlwp;
    214 	int error = 0;
    215 	struct ptyfsmount *pmnt;
    216 	struct ptyfs_args *args = data;
    217 
    218 	if (*data_len < sizeof *args)
    219 		return EINVAL;
    220 
    221 	if (UIO_MX & (UIO_MX - 1)) {
    222 		log(LOG_ERR, "ptyfs: invalid directory entry size");
    223 		return EINVAL;
    224 	}
    225 
    226 	if (mp->mnt_flag & MNT_GETARGS) {
    227 		pmnt = VFSTOPTY(mp);
    228 		if (pmnt == NULL)
    229 			return EIO;
    230 		args->version = PTYFS_ARGSVERSION;
    231 		args->mode = pmnt->pmnt_mode;
    232 		args->gid = pmnt->pmnt_gid;
    233 		*data_len = sizeof *args;
    234 		return 0;
    235 	}
    236 
    237 	/* Don't allow more than one mount */
    238 	if (ptyfs_count)
    239 		return EBUSY;
    240 
    241 	if (mp->mnt_flag & MNT_UPDATE)
    242 		return EOPNOTSUPP;
    243 
    244 	if (args->version != PTYFS_ARGSVERSION)
    245 		return EINVAL;
    246 
    247 	pmnt = malloc(sizeof(struct ptyfsmount), M_PTYFSMNT, M_WAITOK);
    248 
    249 	mp->mnt_data = pmnt;
    250 	pmnt->pmnt_gid = args->gid;
    251 	pmnt->pmnt_mode = args->mode;
    252 	mp->mnt_flag |= MNT_LOCAL;
    253 	vfs_getnewfsid(mp);
    254 
    255 	if ((error = set_statvfs_info(path, UIO_USERSPACE, "ptyfs",
    256 	    UIO_SYSSPACE, mp->mnt_op->vfs_name, mp, l)) != 0) {
    257 		free(pmnt, M_PTYFSMNT);
    258 		return error;
    259 	}
    260 
    261 	/* Point pty access to us */
    262 
    263 	ptm_ptyfspty.arg = mp;
    264 	ptyfs_save_ptm = pty_sethandler(&ptm_ptyfspty);
    265 	ptyfs_count++;
    266 	return 0;
    267 }
    268 
    269 /*ARGSUSED*/
    270 int
    271 ptyfs_start(struct mount *mp, int flags)
    272 {
    273 	return 0;
    274 }
    275 
    276 /*ARGSUSED*/
    277 int
    278 ptyfs_unmount(struct mount *mp, int mntflags)
    279 {
    280 	int error;
    281 	int flags = 0;
    282 
    283 	if (mntflags & MNT_FORCE)
    284 		flags |= FORCECLOSE;
    285 
    286 	if ((error = vflush(mp, 0, flags)) != 0)
    287 		return (error);
    288 
    289 	/* Restore where pty access was pointing */
    290 	(void)pty_sethandler(ptyfs_save_ptm);
    291 	ptyfs_save_ptm = NULL;
    292 	ptm_ptyfspty.arg = NULL;
    293 
    294 	/*
    295 	 * Finally, throw away the ptyfsmount structure
    296 	 */
    297 	free(mp->mnt_data, M_PTYFSMNT);
    298 	mp->mnt_data = NULL;
    299 	ptyfs_count--;
    300 
    301 	return 0;
    302 }
    303 
    304 int
    305 ptyfs_root(struct mount *mp, struct vnode **vpp)
    306 {
    307 	/* setup "." */
    308 	return ptyfs_allocvp(mp, vpp, PTYFSroot, 0, NULL);
    309 }
    310 
    311 /*ARGSUSED*/
    312 int
    313 ptyfs_statvfs(struct mount *mp, struct statvfs *sbp)
    314 {
    315 	sbp->f_bsize = DEV_BSIZE;
    316 	sbp->f_frsize = DEV_BSIZE;
    317 	sbp->f_iosize = DEV_BSIZE;
    318 	sbp->f_blocks = 2;		/* 1K to keep df happy */
    319 	sbp->f_bfree = 0;
    320 	sbp->f_bavail = 0;
    321 	sbp->f_bresvd = 0;
    322 	sbp->f_files = 1024;	/* XXX lie */
    323 	sbp->f_ffree = 128;	/* XXX lie */
    324 	sbp->f_favail = 128;	/* XXX lie */
    325 	sbp->f_fresvd = 0;
    326 	sbp->f_namemax = MAXNAMLEN;
    327 	copy_statvfs_info(sbp, mp);
    328 	return 0;
    329 }
    330 
    331 /*ARGSUSED*/
    332 int
    333 ptyfs_sync(struct mount *mp, int waitfor,
    334     kauth_cred_t uc)
    335 {
    336 	return 0;
    337 }
    338 
    339 /*
    340  * Kernfs flat namespace lookup.
    341  * Currently unsupported.
    342  */
    343 /*ARGSUSED*/
    344 int
    345 ptyfs_vget(struct mount *mp, ino_t ino,
    346     struct vnode **vpp)
    347 {
    348 	return EOPNOTSUPP;
    349 }
    350 
    351 SYSCTL_SETUP(sysctl_vfs_ptyfs_setup, "sysctl vfs.ptyfs subtree setup")
    352 {
    353 
    354 	sysctl_createv(clog, 0, NULL, NULL,
    355 		       CTLFLAG_PERMANENT,
    356 		       CTLTYPE_NODE, "vfs", NULL,
    357 		       NULL, 0, NULL, 0,
    358 		       CTL_VFS, CTL_EOL);
    359 	sysctl_createv(clog, 0, NULL, NULL,
    360 		       CTLFLAG_PERMANENT,
    361 		       CTLTYPE_NODE, "ptyfs",
    362 		       SYSCTL_DESCR("Pty file system"),
    363 		       NULL, 0, NULL, 0,
    364 		       CTL_VFS, 23, CTL_EOL);
    365 	/*
    366 	 * XXX the "23" above could be dynamic, thereby eliminating
    367 	 * one more instance of the "number to vfs" mapping problem,
    368 	 * but "23" is the order as taken from sys/mount.h
    369 	 */
    370 }
    371 
    372 
    373 extern const struct vnodeopv_desc ptyfs_vnodeop_opv_desc;
    374 
    375 const struct vnodeopv_desc * const ptyfs_vnodeopv_descs[] = {
    376 	&ptyfs_vnodeop_opv_desc,
    377 	NULL,
    378 };
    379 
    380 struct vfsops ptyfs_vfsops = {
    381 	MOUNT_PTYFS,
    382 	sizeof (struct ptyfs_args),
    383 	ptyfs_mount,
    384 	ptyfs_start,
    385 	ptyfs_unmount,
    386 	ptyfs_root,
    387 	(void *)eopnotsupp,		/* vfs_quotactl */
    388 	ptyfs_statvfs,
    389 	ptyfs_sync,
    390 	ptyfs_vget,
    391 	(void *)eopnotsupp,		/* vfs_fhtovp */
    392 	(void *)eopnotsupp,		/* vfs_vptofp */
    393 	ptyfs_init,
    394 	ptyfs_reinit,
    395 	ptyfs_done,
    396 	NULL,				/* vfs_mountroot */
    397 	(void *)eopnotsupp,
    398 	(void *)eopnotsupp,
    399 	(void *)eopnotsupp,		/* vfs_suspendctl */
    400 	genfs_renamelock_enter,
    401 	genfs_renamelock_exit,
    402 	(void *)eopnotsupp,
    403 	ptyfs_vnodeopv_descs,
    404 	0,
    405 	{ NULL, NULL },
    406 };
    407 
    408 static int
    409 ptyfs_modcmd(modcmd_t cmd, void *arg)
    410 {
    411 
    412 	switch (cmd) {
    413 	case MODULE_CMD_INIT:
    414 		return vfs_attach(&ptyfs_vfsops);
    415 	case MODULE_CMD_FINI:
    416 		return vfs_detach(&ptyfs_vfsops);
    417 	default:
    418 		return ENOTTY;
    419 	}
    420 }
    421