1/* $NetBSD: ptyfs_vfsops.c,v 1.58 2020/03/16 21:20:10 pgoyette 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 1.58 2020/03/16 21:20:10 pgoyette 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 66MODULE(MODULE_CLASS_VFS, ptyfs, NULL); 67 68MALLOC_JUSTDEFINE(M_PTYFSMNT, "ptyfs mount", "ptyfs mount structures"); 69MALLOC_JUSTDEFINE(M_PTYFSTMP, "ptyfs temp", "ptyfs temporary structures"); 70 71VFS_PROTOS(ptyfs); 72 73static int ptyfs__allocvp(struct mount *, struct lwp *, struct vnode **, 74 dev_t, char); 75static int ptyfs__makename(struct mount *, struct lwp *, char *, size_t, 76 dev_t, char); 77static void ptyfs__getvattr(struct mount *, struct lwp *, struct vattr *); 78static int ptyfs__getmp(struct lwp *, struct mount **); 79 80/* 81 * ptm glue: When we mount, we make ptm point to us. 82 */ 83struct ptm_pty *ptyfs_save_ptm; 84static int ptyfs_count; 85 86static TAILQ_HEAD(, ptyfsmount) ptyfs_head; 87 88struct ptm_pty ptm_ptyfspty = { 89 ptyfs__allocvp, 90 ptyfs__makename, 91 ptyfs__getvattr, 92 ptyfs__getmp, 93}; 94 95static int 96ptyfs__getmp(struct lwp *l, struct mount **mpp) 97{ 98 struct cwdinfo *cwdi = l->l_proc->p_cwdi; 99 struct mount *mp; 100 struct ptyfsmount *pmnt; 101 102 TAILQ_FOREACH(pmnt, &ptyfs_head, pmnt_le) { 103 mp = pmnt->pmnt_mp; 104 if (cwdi->cwdi_rdir == NULL) 105 goto ok; 106 107 if (vn_isunder(mp->mnt_vnodecovered, cwdi->cwdi_rdir, l)) 108 goto ok; 109 } 110 *mpp = NULL; 111 return EOPNOTSUPP; 112ok: 113 *mpp = mp; 114 return 0; 115} 116 117static const char * 118ptyfs__getpath(struct lwp *l, const struct mount *mp) 119{ 120#define MAXBUF (sizeof(mp->mnt_stat.f_mntonname) + 32) 121 struct cwdinfo *cwdi = l->l_proc->p_cwdi; 122 char *buf; 123 const char *rv; 124 size_t len; 125 char *bp; 126 int error; 127 128 rv = mp->mnt_stat.f_mntonname; 129 if (cwdi->cwdi_rdir == NULL) 130 return rv; 131 132 buf = malloc(MAXBUF, M_TEMP, M_WAITOK); 133 bp = buf + MAXBUF; 134 *--bp = '\0'; 135 error = getcwd_common(mp->mnt_vnodecovered, cwdi->cwdi_rdir, &bp, 136 buf, MAXBUF / 2, 0, l); 137 if (error) { /* Mount point is out of rdir */ 138 rv = NULL; 139 goto out; 140 } 141 142 len = strlen(bp); 143 if (len < sizeof(mp->mnt_stat.f_mntonname)) /* XXX */ 144 rv += strlen(rv) - len; 145out: 146 free(buf, M_TEMP); 147 return rv; 148} 149 150static int 151ptyfs__makename(struct mount *mp, struct lwp *l, char *tbuf, size_t bufsiz, 152 dev_t dev, char ms) 153{ 154 size_t len; 155 const char *np; 156 int pty = minor(dev); 157 158 switch (ms) { 159 case 'p': 160 /* We don't provide access to the master, should we? */ 161 len = snprintf(tbuf, bufsiz, "/dev/null"); 162 break; 163 case 't': 164 /* 165 * We support traditional ptys, so we can get here, 166 * if pty had been opened before PTYFS was mounted, 167 * or was opened through /dev/ptyXX devices. 168 * Return it only outside chroot for more security . 169 */ 170 if (l->l_proc->p_cwdi->cwdi_rdir == NULL 171 && ptyfs_save_ptm != NULL 172 && ptyfs_next_active(mp, pty) != pty) 173 return (*ptyfs_save_ptm->makename)(mp, l, 174 tbuf, bufsiz, dev, ms); 175 176 np = ptyfs__getpath(l, mp); 177 if (np == NULL) 178 return EOPNOTSUPP; 179 len = snprintf(tbuf, bufsiz, "%s/%llu", np, 180 (unsigned long long)minor(dev)); 181 break; 182 default: 183 return EINVAL; 184 } 185 186 return len >= bufsiz ? ENOSPC : 0; 187} 188 189 190static int 191/*ARGSUSED*/ 192ptyfs__allocvp(struct mount *mp, struct lwp *l, struct vnode **vpp, 193 dev_t dev, char ms) 194{ 195 int error; 196 ptyfstype type; 197 198 switch (ms) { 199 case 'p': 200 type = PTYFSptc; 201 break; 202 case 't': 203 type = PTYFSpts; 204 break; 205 default: 206 return EINVAL; 207 } 208 209 error = ptyfs_allocvp(mp, vpp, type, minor(dev)); 210 if (error) 211 return error; 212 error = vn_lock(*vpp, LK_EXCLUSIVE); 213 if (error) { 214 vrele(*vpp); 215 *vpp = NULL; 216 return error; 217 } 218 if (type == PTYFSptc) 219 ptyfs_set_active(mp, minor(dev)); 220 return 0; 221} 222 223 224static void 225ptyfs__getvattr(struct mount *mp, struct lwp *l, struct vattr *vattr) 226{ 227 struct ptyfsmount *pmnt = VFSTOPTY(mp); 228 vattr_null(vattr); 229 /* get real uid */ 230 vattr->va_uid = kauth_cred_getuid(l->l_cred); 231 vattr->va_gid = pmnt->pmnt_gid; 232 vattr->va_mode = pmnt->pmnt_mode; 233} 234 235 236void 237ptyfs_init(void) 238{ 239 240 TAILQ_INIT(&ptyfs_head); 241 malloc_type_attach(M_PTYFSMNT); 242 malloc_type_attach(M_PTYFSTMP); 243 ptyfs_hashinit(); 244} 245 246void 247ptyfs_reinit(void) 248{ 249 250} 251 252void 253ptyfs_done(void) 254{ 255 256 ptyfs_hashdone(); 257 malloc_type_detach(M_PTYFSTMP); 258 malloc_type_detach(M_PTYFSMNT); 259} 260 261#define OSIZE sizeof(struct { int f; gid_t g; mode_t m; }) 262/* 263 * Mount the Pseudo tty params filesystem 264 */ 265int 266ptyfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len) 267{ 268 struct lwp *l = curlwp; 269 int error = 0; 270 struct ptyfsmount *pmnt; 271 struct ptyfs_args *args = data; 272 273 if (args == NULL) 274 return EINVAL; 275 if (*data_len != sizeof *args) { 276 if (*data_len != OSIZE || args->version >= PTYFS_ARGSVERSION) 277 return EINVAL; 278 } 279 280 if (UIO_MX & (UIO_MX - 1)) { 281 log(LOG_ERR, "ptyfs: invalid directory entry size"); 282 return EINVAL; 283 } 284 285 if (mp->mnt_flag & MNT_GETARGS) { 286 pmnt = VFSTOPTY(mp); 287 if (pmnt == NULL) 288 return EIO; 289 args->mode = pmnt->pmnt_mode; 290 args->gid = pmnt->pmnt_gid; 291 if (args->version >= PTYFS_ARGSVERSION) { 292 args->flags = pmnt->pmnt_flags; 293 *data_len = sizeof *args; 294 } else { 295 *data_len = OSIZE; 296 } 297 return 0; 298 } 299 300#if 0 301 /* Don't allow more than one mount */ 302 if (ptyfs_count) 303 return EBUSY; 304#endif 305 306 if (mp->mnt_flag & MNT_UPDATE) 307 return EOPNOTSUPP; 308 309 if (args->version > PTYFS_ARGSVERSION) 310 return EINVAL; 311 312 pmnt = malloc(sizeof(struct ptyfsmount), M_PTYFSMNT, M_WAITOK); 313 314 mp->mnt_data = pmnt; 315 mutex_init(&pmnt->pmnt_lock, MUTEX_DEFAULT, IPL_NONE); 316 pmnt->pmnt_gid = args->gid; 317 pmnt->pmnt_mode = args->mode; 318 if (args->version >= PTYFS_ARGSVERSION) 319 pmnt->pmnt_flags = args->flags; 320 else 321 pmnt->pmnt_flags = 0; 322 pmnt->pmnt_bitmap_size = 0; 323 pmnt->pmnt_bitmap = NULL; 324 mp->mnt_flag |= MNT_LOCAL; 325 vfs_getnewfsid(mp); 326 327 if ((error = set_statvfs_info(path, UIO_USERSPACE, "ptyfs", 328 UIO_SYSSPACE, mp->mnt_op->vfs_name, mp, l)) != 0) { 329 free(pmnt, M_PTYFSMNT); 330 return error; 331 } 332 333 pmnt->pmnt_mp = mp; 334 TAILQ_INSERT_TAIL(&ptyfs_head, pmnt, pmnt_le); 335 if (ptyfs_count++ == 0) { 336 /* Point pty access to us */ 337 ptyfs_save_ptm = pty_sethandler(&ptm_ptyfspty); 338 } 339 return 0; 340} 341 342/*ARGSUSED*/ 343int 344ptyfs_start(struct mount *mp, int flags) 345{ 346 return 0; 347} 348 349/*ARGSUSED*/ 350int 351ptyfs_unmount(struct mount *mp, int mntflags) 352{ 353 int error; 354 int flags = 0; 355 struct ptyfsmount *pmnt; 356 357 if (mntflags & MNT_FORCE) 358 flags |= FORCECLOSE; 359 360 if ((error = vflush(mp, 0, flags)) != 0) 361 return error; 362 363 ptyfs_count--; 364 if (ptyfs_count == 0) { 365 /* Restore where pty access was pointing */ 366 (void)pty_sethandler(ptyfs_save_ptm); 367 ptyfs_save_ptm = NULL; 368 } 369 TAILQ_FOREACH(pmnt, &ptyfs_head, pmnt_le) { 370 if (pmnt->pmnt_mp == mp) { 371 TAILQ_REMOVE(&ptyfs_head, pmnt, pmnt_le); 372 break; 373 } 374 } 375 376 /* 377 * Finally, throw away the ptyfsmount structure 378 */ 379 if (pmnt->pmnt_bitmap_size > 0) 380 kmem_free(pmnt->pmnt_bitmap, pmnt->pmnt_bitmap_size); 381 mutex_destroy(&pmnt->pmnt_lock); 382 free(mp->mnt_data, M_PTYFSMNT); 383 mp->mnt_data = NULL; 384 385 return 0; 386} 387 388int 389ptyfs_root(struct mount *mp, int lktype, struct vnode **vpp) 390{ 391 int error; 392 393 /* setup "." */ 394 error = ptyfs_allocvp(mp, vpp, PTYFSroot, 0); 395 if (error) 396 return error; 397 error = vn_lock(*vpp, lktype); 398 if (error) { 399 vrele(*vpp); 400 *vpp = NULL; 401 return error; 402 } 403 return 0; 404} 405 406/*ARGSUSED*/ 407int 408ptyfs_sync(struct mount *mp, int waitfor, 409 kauth_cred_t uc) 410{ 411 return 0; 412} 413 414/* 415 * Initialize this vnode / ptynode pair. 416 * Only for the slave side of a pty, caller assures 417 * no other thread will try to load this node. 418 */ 419int 420ptyfs_loadvnode(struct mount *mp, struct vnode *vp, 421 const void *key, size_t key_len, const void **new_key) 422{ 423 struct ptyfskey pkey; 424 struct ptyfsnode *ptyfs; 425 426 KASSERT(key_len == sizeof(pkey)); 427 memcpy(&pkey, key, key_len); 428 429 ptyfs = ptyfs_get_node(pkey.ptk_type, pkey.ptk_pty); 430 KASSERT(memcmp(&ptyfs->ptyfs_key, &pkey, sizeof(pkey)) == 0); 431 432 switch (pkey.ptk_type) { 433 case PTYFSroot: /* /pts = dr-xr-xr-x */ 434 vp->v_type = VDIR; 435 vp->v_vflag = VV_ROOT; 436 break; 437 438 case PTYFSpts: /* /pts/N = cxxxxxxxxx */ 439 case PTYFSptc: /* controlling side = cxxxxxxxxx */ 440 vp->v_type = VCHR; 441 spec_node_init(vp, PTYFS_MAKEDEV(ptyfs)); 442 break; 443 default: 444 panic("ptyfs_loadvnode"); 445 } 446 447 vp->v_tag = VT_PTYFS; 448 vp->v_op = ptyfs_vnodeop_p; 449 vp->v_data = ptyfs; 450 uvm_vnp_setsize(vp, 0); 451 *new_key = &ptyfs->ptyfs_key; 452 return 0; 453} 454 455/* 456 * Kernfs flat namespace lookup. 457 * Currently unsupported. 458 */ 459/*ARGSUSED*/ 460int 461ptyfs_vget(struct mount *mp, ino_t ino, int lktype, 462 struct vnode **vpp) 463{ 464 return EOPNOTSUPP; 465} 466 467extern const struct vnodeopv_desc ptyfs_vnodeop_opv_desc; 468 469const struct vnodeopv_desc * const ptyfs_vnodeopv_descs[] = { 470 &ptyfs_vnodeop_opv_desc, 471 NULL, 472}; 473 474struct vfsops ptyfs_vfsops = { 475 .vfs_name = MOUNT_PTYFS, 476 .vfs_min_mount_data = sizeof (struct ptyfs_args), 477 .vfs_mount = ptyfs_mount, 478 .vfs_start = ptyfs_start, 479 .vfs_unmount = ptyfs_unmount, 480 .vfs_root = ptyfs_root, 481 .vfs_quotactl = (void *)eopnotsupp, 482 .vfs_statvfs = genfs_statvfs, 483 .vfs_sync = ptyfs_sync, 484 .vfs_vget = ptyfs_vget, 485 .vfs_loadvnode = ptyfs_loadvnode, 486 .vfs_fhtovp = (void *)eopnotsupp, 487 .vfs_vptofh = (void *)eopnotsupp, 488 .vfs_init = ptyfs_init, 489 .vfs_reinit = ptyfs_reinit, 490 .vfs_done = ptyfs_done, 491 .vfs_snapshot = (void *)eopnotsupp, 492 .vfs_extattrctl = (void *)eopnotsupp, 493 .vfs_suspendctl = genfs_suspendctl, 494 .vfs_renamelock_enter = genfs_renamelock_enter, 495 .vfs_renamelock_exit = genfs_renamelock_exit, 496 .vfs_fsync = (void *)eopnotsupp, 497 .vfs_opv_descs = ptyfs_vnodeopv_descs 498}; 499 500SYSCTL_SETUP(ptyfs_sysctl_setup, "ptyfs sysctl") 501{ 502 503 sysctl_createv(clog, 0, NULL, NULL, 504 CTLFLAG_PERMANENT, 505 CTLTYPE_NODE, "ptyfs", 506 SYSCTL_DESCR("Pty file system"), 507 NULL, 0, NULL, 0, 508 CTL_VFS, 23, CTL_EOL); 509 /* 510 * XXX the "23" above could be dynamic, thereby eliminating 511 * one more instance of the "number to vfs" mapping problem, 512 * but "23" is the order as taken from sys/mount.h 513 */ 514} 515 516static int 517ptyfs_modcmd(modcmd_t cmd, void *arg) 518{ 519 int error; 520 521 switch (cmd) { 522 case MODULE_CMD_INIT: 523 error = vfs_attach(&ptyfs_vfsops); 524 if (error != 0) 525 break; 526 break; 527 case MODULE_CMD_FINI: 528 error = vfs_detach(&ptyfs_vfsops); 529 if (error != 0) 530 break; 531 break; 532 default: 533 error = ENOTTY; 534 break; 535 } 536 537 return (error); 538} 539