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ptyfs_vfsops.c revision 1.30 
      1 /*	$NetBSD: ptyfs_vfsops.c,v 1.30 2007/11/26 19:01:49 pooka 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 1.30 2007/11/26 19:01:49 pooka 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 
     61 #include <fs/ptyfs/ptyfs.h>
     62 #include <miscfs/specfs/specdev.h>
     63 
     64 MALLOC_JUSTDEFINE(M_PTYFSMNT, "ptyfs mount", "ptyfs mount structures");
     65 MALLOC_JUSTDEFINE(M_PTYFSTMP, "ptyfs temp", "ptyfs temporary structures");
     66 
     67 VFS_PROTOS(ptyfs);
     68 
     69 static int ptyfs__allocvp(struct ptm_pty *, struct lwp *, struct vnode **,
     70     dev_t, char);
     71 static int ptyfs__makename(struct ptm_pty *, struct lwp *, char *, size_t,
     72     dev_t, char);
     73 static void ptyfs__getvattr(struct ptm_pty *, struct lwp *, struct vattr *);
     74 
     75 /*
     76  * ptm glue: When we mount, we make ptm point to us.
     77  */
     78 struct ptm_pty *ptyfs_save_ptm;
     79 static int ptyfs_count;
     80 
     81 struct ptm_pty ptm_ptyfspty = {
     82 	ptyfs__allocvp,
     83 	ptyfs__makename,
     84 	ptyfs__getvattr,
     85 	NULL
     86 };
     87 
     88 static const char *
     89 ptyfs__getpath(struct lwp *l, const struct mount *mp)
     90 {
     91 #define MAXBUF (sizeof(mp->mnt_stat.f_mntonname) + 32)
     92 	struct cwdinfo *cwdi = l->l_proc->p_cwdi;
     93 	char *buf;
     94 	const char *rv;
     95 	size_t len;
     96 	char *bp;
     97 	int error;
     98 
     99 	rv = mp->mnt_stat.f_mntonname;
    100 	if (cwdi->cwdi_rdir == NULL)
    101 		return rv;
    102 
    103 	buf = malloc(MAXBUF, M_TEMP, M_WAITOK);
    104 	bp = buf + MAXBUF;
    105 	*--bp = '\0';
    106 	error = getcwd_common(cwdi->cwdi_rdir, rootvnode, &bp,
    107 	    buf, MAXBUF / 2, 0, l);
    108 	if (error)	/* XXX */
    109 		goto out;
    110 
    111 	len = strlen(bp);
    112 	if (len < sizeof(mp->mnt_stat.f_mntonname))	/* XXX */
    113 		rv += len;
    114 out:
    115 	free(buf, M_TEMP);
    116 	return rv;
    117 }
    118 
    119 static int
    120 ptyfs__makename(struct ptm_pty *pt, struct lwp *l, char *tbuf, size_t bufsiz,
    121     dev_t dev, char ms)
    122 {
    123 	struct mount *mp = pt->arg;
    124 	size_t len;
    125 
    126 	switch (ms) {
    127 	case 'p':
    128 		/* We don't provide access to the master, should we? */
    129 		len = snprintf(tbuf, bufsiz, "/dev/null");
    130 		break;
    131 	case 't':
    132 		len = snprintf(tbuf, bufsiz, "%s/%d", ptyfs__getpath(l, mp),
    133 		    minor(dev));
    134 		break;
    135 	default:
    136 		return EINVAL;
    137 	}
    138 
    139 	return len >= bufsiz ? ENOSPC : 0;
    140 }
    141 
    142 
    143 static int
    144 /*ARGSUSED*/
    145 ptyfs__allocvp(struct ptm_pty *pt, struct lwp *l, struct vnode **vpp,
    146     dev_t dev, char ms)
    147 {
    148 	struct mount *mp = pt->arg;
    149 	ptyfstype type;
    150 
    151 	switch (ms) {
    152 	case 'p':
    153 		type = PTYFSptc;
    154 		break;
    155 	case 't':
    156 		type = PTYFSpts;
    157 		break;
    158 	default:
    159 		return EINVAL;
    160 	}
    161 
    162 	return ptyfs_allocvp(mp, vpp, type, minor(dev), l);
    163 }
    164 
    165 
    166 static void
    167 ptyfs__getvattr(struct ptm_pty *pt, struct lwp *l, struct vattr *vattr)
    168 {
    169 	struct mount *mp = pt->arg;
    170 	struct ptyfsmount *pmnt = VFSTOPTY(mp);
    171 	VATTR_NULL(vattr);
    172 	/* get real uid */
    173 	vattr->va_uid = kauth_cred_getuid(l->l_cred);
    174 	vattr->va_gid = pmnt->pmnt_gid;
    175 	vattr->va_mode = pmnt->pmnt_mode;
    176 }
    177 
    178 
    179 void
    180 ptyfs_init(void)
    181 {
    182 
    183 	malloc_type_attach(M_PTYFSMNT);
    184 	malloc_type_attach(M_PTYFSTMP);
    185 	ptyfs_hashinit();
    186 }
    187 
    188 void
    189 ptyfs_reinit(void)
    190 {
    191 	ptyfs_hashreinit();
    192 }
    193 
    194 void
    195 ptyfs_done(void)
    196 {
    197 
    198 	ptyfs_hashdone();
    199 	malloc_type_detach(M_PTYFSTMP);
    200 	malloc_type_detach(M_PTYFSMNT);
    201 }
    202 
    203 /*
    204  * Mount the Pseudo tty params filesystem
    205  */
    206 int
    207 ptyfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
    208 {
    209 	struct lwp *l = curlwp;
    210 	int error = 0;
    211 	struct ptyfsmount *pmnt;
    212 	struct ptyfs_args *args = data;
    213 
    214 	if (*data_len < sizeof *args)
    215 		return EINVAL;
    216 
    217 	if (UIO_MX & (UIO_MX - 1)) {
    218 		log(LOG_ERR, "ptyfs: invalid directory entry size");
    219 		return EINVAL;
    220 	}
    221 
    222 	if (mp->mnt_flag & MNT_GETARGS) {
    223 		pmnt = VFSTOPTY(mp);
    224 		if (pmnt == NULL)
    225 			return EIO;
    226 		args->version = PTYFS_ARGSVERSION;
    227 		args->mode = pmnt->pmnt_mode;
    228 		args->gid = pmnt->pmnt_gid;
    229 		*data_len = sizeof *args;
    230 		return 0;
    231 	}
    232 
    233 	/* Don't allow more than one mount */
    234 	if (ptyfs_count)
    235 		return EBUSY;
    236 
    237 	if (mp->mnt_flag & MNT_UPDATE)
    238 		return EOPNOTSUPP;
    239 
    240 	if (args->version != PTYFS_ARGSVERSION)
    241 		return EINVAL;
    242 
    243 	pmnt = malloc(sizeof(struct ptyfsmount), M_PTYFSMNT, M_WAITOK);
    244 
    245 	mp->mnt_data = pmnt;
    246 	pmnt->pmnt_gid = args->gid;
    247 	pmnt->pmnt_mode = args->mode;
    248 	mp->mnt_flag |= MNT_LOCAL;
    249 	vfs_getnewfsid(mp);
    250 
    251 	if ((error = set_statvfs_info(path, UIO_USERSPACE, "ptyfs",
    252 	    UIO_SYSSPACE, mp->mnt_op->vfs_name, mp, l)) != 0) {
    253 		free(pmnt, M_UFSMNT);
    254 		return error;
    255 	}
    256 
    257 	/* Point pty access to us */
    258 
    259 	ptm_ptyfspty.arg = mp;
    260 	ptyfs_save_ptm = pty_sethandler(&ptm_ptyfspty);
    261 	ptyfs_count++;
    262 	return 0;
    263 }
    264 
    265 /*ARGSUSED*/
    266 int
    267 ptyfs_start(struct mount *mp, int flags)
    268 {
    269 	return 0;
    270 }
    271 
    272 /*ARGSUSED*/
    273 int
    274 ptyfs_unmount(struct mount *mp, int mntflags)
    275 {
    276 	int error;
    277 	int flags = 0;
    278 
    279 	if (mntflags & MNT_FORCE)
    280 		flags |= FORCECLOSE;
    281 
    282 	if ((error = vflush(mp, 0, flags)) != 0)
    283 		return (error);
    284 
    285 	/* Restore where pty access was pointing */
    286 	(void)pty_sethandler(ptyfs_save_ptm);
    287 	ptyfs_save_ptm = NULL;
    288 	ptm_ptyfspty.arg = NULL;
    289 
    290 	/*
    291 	 * Finally, throw away the ptyfsmount structure
    292 	 */
    293 	free(mp->mnt_data, M_UFSMNT);
    294 	mp->mnt_data = 0;
    295 	ptyfs_count--;
    296 
    297 	return 0;
    298 }
    299 
    300 int
    301 ptyfs_root(struct mount *mp, struct vnode **vpp)
    302 {
    303 	/* setup "." */
    304 	return ptyfs_allocvp(mp, vpp, PTYFSroot, 0, NULL);
    305 }
    306 
    307 /*ARGSUSED*/
    308 int
    309 ptyfs_statvfs(struct mount *mp, struct statvfs *sbp)
    310 {
    311 	sbp->f_bsize = DEV_BSIZE;
    312 	sbp->f_frsize = DEV_BSIZE;
    313 	sbp->f_iosize = DEV_BSIZE;
    314 	sbp->f_blocks = 2;		/* 1K to keep df happy */
    315 	sbp->f_bfree = 0;
    316 	sbp->f_bavail = 0;
    317 	sbp->f_bresvd = 0;
    318 	sbp->f_files = 1024;	/* XXX lie */
    319 	sbp->f_ffree = 128;	/* XXX lie */
    320 	sbp->f_favail = 128;	/* XXX lie */
    321 	sbp->f_fresvd = 0;
    322 	sbp->f_namemax = MAXNAMLEN;
    323 	copy_statvfs_info(sbp, mp);
    324 	return 0;
    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 SYSCTL_SETUP(sysctl_vfs_ptyfs_setup, "sysctl vfs.ptyfs subtree setup")
    348 {
    349 
    350 	sysctl_createv(clog, 0, NULL, NULL,
    351 		       CTLFLAG_PERMANENT,
    352 		       CTLTYPE_NODE, "vfs", NULL,
    353 		       NULL, 0, NULL, 0,
    354 		       CTL_VFS, CTL_EOL);
    355 	sysctl_createv(clog, 0, NULL, NULL,
    356 		       CTLFLAG_PERMANENT,
    357 		       CTLTYPE_NODE, "ptyfs",
    358 		       SYSCTL_DESCR("Pty file system"),
    359 		       NULL, 0, NULL, 0,
    360 		       CTL_VFS, 23, CTL_EOL);
    361 	/*
    362 	 * XXX the "23" above could be dynamic, thereby eliminating
    363 	 * one more instance of the "number to vfs" mapping problem,
    364 	 * but "23" is the order as taken from sys/mount.h
    365 	 */
    366 }
    367 
    368 
    369 extern const struct vnodeopv_desc ptyfs_vnodeop_opv_desc;
    370 
    371 const struct vnodeopv_desc * const ptyfs_vnodeopv_descs[] = {
    372 	&ptyfs_vnodeop_opv_desc,
    373 	NULL,
    374 };
    375 
    376 struct vfsops ptyfs_vfsops = {
    377 	MOUNT_PTYFS,
    378 	sizeof (struct ptyfs_args),
    379 	ptyfs_mount,
    380 	ptyfs_start,
    381 	ptyfs_unmount,
    382 	ptyfs_root,
    383 	(void *)eopnotsupp,		/* vfs_quotactl */
    384 	ptyfs_statvfs,
    385 	ptyfs_sync,
    386 	ptyfs_vget,
    387 	(void *)eopnotsupp,		/* vfs_fhtovp */
    388 	(void *)eopnotsupp,		/* vfs_vptofp */
    389 	ptyfs_init,
    390 	ptyfs_reinit,
    391 	ptyfs_done,
    392 	NULL,				/* vfs_mountroot */
    393 	(void *)eopnotsupp,
    394 	(void *)eopnotsupp,
    395 	(void *)eopnotsupp,		/* vfs_suspendctl */
    396 	ptyfs_vnodeopv_descs,
    397 	0,
    398 	{ NULL, NULL },
    399 };
    400 VFS_ATTACH(ptyfs_vfsops);
    401