1 /* $NetBSD: ptyfs_vfsops.c,v 1.50 2014/04/16 18:55:18 maxv 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 1.50 2014/04/16 18:55:18 maxv 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 mount *, struct lwp *, struct vnode **, 76 dev_t, char); 77 static int ptyfs__makename(struct mount *, struct lwp *, char *, size_t, 78 dev_t, char); 79 static void ptyfs__getvattr(struct mount *, struct lwp *, struct vattr *); 80 static int ptyfs__getmp(struct lwp *, struct mount **); 81 82 /* 83 * ptm glue: When we mount, we make ptm point to us. 84 */ 85 struct ptm_pty *ptyfs_save_ptm; 86 static int ptyfs_count; 87 88 static TAILQ_HEAD(, ptyfsmount) ptyfs_head; 89 90 struct ptm_pty ptm_ptyfspty = { 91 ptyfs__allocvp, 92 ptyfs__makename, 93 ptyfs__getvattr, 94 ptyfs__getmp, 95 }; 96 97 static int 98 ptyfs__getmp(struct lwp *l, struct mount **mpp) 99 { 100 struct cwdinfo *cwdi = l->l_proc->p_cwdi; 101 struct mount *mp; 102 struct ptyfsmount *pmnt; 103 104 TAILQ_FOREACH(pmnt, &ptyfs_head, pmnt_le) { 105 mp = pmnt->pmnt_mp; 106 if (cwdi->cwdi_rdir == NULL) 107 goto ok; 108 109 if (vn_isunder(mp->mnt_vnodecovered, cwdi->cwdi_rdir, l)) 110 goto ok; 111 } 112 *mpp = NULL; 113 return EOPNOTSUPP; 114 ok: 115 *mpp = mp; 116 return 0; 117 } 118 119 static const char * 120 ptyfs__getpath(struct lwp *l, const struct mount *mp) 121 { 122 #define MAXBUF (sizeof(mp->mnt_stat.f_mntonname) + 32) 123 struct cwdinfo *cwdi = l->l_proc->p_cwdi; 124 char *buf; 125 const char *rv; 126 size_t len; 127 char *bp; 128 int error; 129 130 rv = mp->mnt_stat.f_mntonname; 131 if (cwdi->cwdi_rdir == NULL) 132 return rv; 133 134 buf = malloc(MAXBUF, M_TEMP, M_WAITOK); 135 bp = buf + MAXBUF; 136 *--bp = '\0'; 137 error = getcwd_common(mp->mnt_vnodecovered, cwdi->cwdi_rdir, &bp, 138 buf, MAXBUF / 2, 0, l); 139 if (error) { /* Mount point is out of rdir */ 140 rv = NULL; 141 goto out; 142 } 143 144 len = strlen(bp); 145 if (len < sizeof(mp->mnt_stat.f_mntonname)) /* XXX */ 146 rv += strlen(rv) - len; 147 out: 148 free(buf, M_TEMP); 149 return rv; 150 } 151 152 static int 153 ptyfs__makename(struct mount *mp, struct lwp *l, char *tbuf, size_t bufsiz, 154 dev_t dev, char ms) 155 { 156 size_t len; 157 const char *np; 158 159 switch (ms) { 160 case 'p': 161 /* We don't provide access to the master, should we? */ 162 len = snprintf(tbuf, bufsiz, "/dev/null"); 163 break; 164 case 't': 165 /* 166 * We support traditional ptys, so we can get here, 167 * if pty had been opened before PTYFS was mounted, 168 * or was opened through /dev/ptyXX devices. 169 * Return it only outside chroot for more security . 170 */ 171 if (l->l_proc->p_cwdi->cwdi_rdir == NULL 172 && ptyfs_save_ptm != NULL 173 && ptyfs_used_get(PTYFSptc, minor(dev), mp, 0) == NULL) 174 return (*ptyfs_save_ptm->makename)(mp, l, 175 tbuf, bufsiz, dev, ms); 176 177 np = ptyfs__getpath(l, mp); 178 if (np == NULL) 179 return EOPNOTSUPP; 180 len = snprintf(tbuf, bufsiz, "%s/%llu", np, 181 (unsigned long long)minor(dev)); 182 break; 183 default: 184 return EINVAL; 185 } 186 187 return len >= bufsiz ? ENOSPC : 0; 188 } 189 190 191 static int 192 /*ARGSUSED*/ 193 ptyfs__allocvp(struct mount *mp, struct lwp *l, struct vnode **vpp, 194 dev_t dev, char ms) 195 { 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 return ptyfs_allocvp(mp, vpp, type, minor(dev), l); 210 } 211 212 213 static void 214 ptyfs__getvattr(struct mount *mp, struct lwp *l, struct vattr *vattr) 215 { 216 struct ptyfsmount *pmnt = VFSTOPTY(mp); 217 vattr_null(vattr); 218 /* get real uid */ 219 vattr->va_uid = kauth_cred_getuid(l->l_cred); 220 vattr->va_gid = pmnt->pmnt_gid; 221 vattr->va_mode = pmnt->pmnt_mode; 222 } 223 224 225 void 226 ptyfs_init(void) 227 { 228 229 TAILQ_INIT(&ptyfs_head); 230 malloc_type_attach(M_PTYFSMNT); 231 malloc_type_attach(M_PTYFSTMP); 232 ptyfs_hashinit(); 233 } 234 235 void 236 ptyfs_reinit(void) 237 { 238 ptyfs_hashreinit(); 239 } 240 241 void 242 ptyfs_done(void) 243 { 244 245 ptyfs_hashdone(); 246 malloc_type_detach(M_PTYFSTMP); 247 malloc_type_detach(M_PTYFSMNT); 248 } 249 250 #define OSIZE sizeof(struct { int f; gid_t g; mode_t m; }) 251 /* 252 * Mount the Pseudo tty params filesystem 253 */ 254 int 255 ptyfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len) 256 { 257 struct lwp *l = curlwp; 258 int error = 0; 259 struct ptyfsmount *pmnt; 260 struct ptyfs_args *args = data; 261 262 if (args == NULL) 263 return EINVAL; 264 if (*data_len != sizeof *args && *data_len != OSIZE) 265 return EINVAL; 266 267 if (UIO_MX & (UIO_MX - 1)) { 268 log(LOG_ERR, "ptyfs: invalid directory entry size"); 269 return EINVAL; 270 } 271 272 if (mp->mnt_flag & MNT_GETARGS) { 273 pmnt = VFSTOPTY(mp); 274 if (pmnt == NULL) 275 return EIO; 276 args->mode = pmnt->pmnt_mode; 277 args->gid = pmnt->pmnt_gid; 278 if (args->version >= PTYFS_ARGSVERSION) { 279 args->flags = pmnt->pmnt_flags; 280 *data_len = sizeof *args; 281 } else { 282 *data_len = OSIZE; 283 } 284 return 0; 285 } 286 287 #if 0 288 /* Don't allow more than one mount */ 289 if (ptyfs_count) 290 return EBUSY; 291 #endif 292 293 if (mp->mnt_flag & MNT_UPDATE) 294 return EOPNOTSUPP; 295 296 if (args->version > PTYFS_ARGSVERSION) 297 return EINVAL; 298 299 pmnt = malloc(sizeof(struct ptyfsmount), M_PTYFSMNT, M_WAITOK); 300 301 mp->mnt_data = pmnt; 302 pmnt->pmnt_gid = args->gid; 303 pmnt->pmnt_mode = args->mode; 304 if (args->version >= PTYFS_ARGSVERSION) 305 pmnt->pmnt_flags = args->flags; 306 else 307 pmnt->pmnt_flags = 0; 308 mp->mnt_flag |= MNT_LOCAL; 309 vfs_getnewfsid(mp); 310 311 if ((error = set_statvfs_info(path, UIO_USERSPACE, "ptyfs", 312 UIO_SYSSPACE, mp->mnt_op->vfs_name, mp, l)) != 0) { 313 free(pmnt, M_PTYFSMNT); 314 return error; 315 } 316 317 pmnt->pmnt_mp = mp; 318 TAILQ_INSERT_TAIL(&ptyfs_head, pmnt, pmnt_le); 319 if (ptyfs_count++ == 0) { 320 /* Point pty access to us */ 321 ptyfs_save_ptm = pty_sethandler(&ptm_ptyfspty); 322 } 323 return 0; 324 } 325 326 /*ARGSUSED*/ 327 int 328 ptyfs_start(struct mount *mp, int flags) 329 { 330 return 0; 331 } 332 333 /*ARGSUSED*/ 334 int 335 ptyfs_unmount(struct mount *mp, int mntflags) 336 { 337 int error; 338 int flags = 0; 339 struct ptyfsmount *pmnt; 340 341 if (mntflags & MNT_FORCE) 342 flags |= FORCECLOSE; 343 344 if ((error = vflush(mp, 0, flags)) != 0) 345 return error; 346 347 ptyfs_count--; 348 if (ptyfs_count == 0) { 349 /* Restore where pty access was pointing */ 350 (void)pty_sethandler(ptyfs_save_ptm); 351 ptyfs_save_ptm = NULL; 352 } 353 TAILQ_FOREACH(pmnt, &ptyfs_head, pmnt_le) { 354 if (pmnt->pmnt_mp == mp) { 355 TAILQ_REMOVE(&ptyfs_head, pmnt, pmnt_le); 356 break; 357 } 358 } 359 360 /* 361 * Finally, throw away the ptyfsmount structure 362 */ 363 free(mp->mnt_data, M_PTYFSMNT); 364 mp->mnt_data = NULL; 365 366 return 0; 367 } 368 369 int 370 ptyfs_root(struct mount *mp, struct vnode **vpp) 371 { 372 /* setup "." */ 373 return ptyfs_allocvp(mp, vpp, PTYFSroot, 0, NULL); 374 } 375 376 /*ARGSUSED*/ 377 int 378 ptyfs_sync(struct mount *mp, int waitfor, 379 kauth_cred_t uc) 380 { 381 return 0; 382 } 383 384 /* 385 * Kernfs flat namespace lookup. 386 * Currently unsupported. 387 */ 388 /*ARGSUSED*/ 389 int 390 ptyfs_vget(struct mount *mp, ino_t ino, 391 struct vnode **vpp) 392 { 393 return EOPNOTSUPP; 394 } 395 396 extern const struct vnodeopv_desc ptyfs_vnodeop_opv_desc; 397 398 const struct vnodeopv_desc * const ptyfs_vnodeopv_descs[] = { 399 &ptyfs_vnodeop_opv_desc, 400 NULL, 401 }; 402 403 struct vfsops ptyfs_vfsops = { 404 .vfs_name = MOUNT_PTYFS, 405 .vfs_min_mount_data = sizeof (struct ptyfs_args), 406 .vfs_mount = ptyfs_mount, 407 .vfs_start = ptyfs_start, 408 .vfs_unmount = ptyfs_unmount, 409 .vfs_root = ptyfs_root, 410 .vfs_quotactl = (void *)eopnotsupp, 411 .vfs_statvfs = genfs_statvfs, 412 .vfs_sync = ptyfs_sync, 413 .vfs_vget = ptyfs_vget, 414 .vfs_fhtovp = (void *)eopnotsupp, 415 .vfs_vptofh = (void *)eopnotsupp, 416 .vfs_init = ptyfs_init, 417 .vfs_reinit = ptyfs_reinit, 418 .vfs_done = ptyfs_done, 419 .vfs_snapshot = (void *)eopnotsupp, 420 .vfs_extattrctl = (void *)eopnotsupp, 421 .vfs_suspendctl = (void *)eopnotsupp, 422 .vfs_renamelock_enter = genfs_renamelock_enter, 423 .vfs_renamelock_exit = genfs_renamelock_exit, 424 .vfs_fsync = (void *)eopnotsupp, 425 .vfs_opv_descs = ptyfs_vnodeopv_descs 426 }; 427 428 static int 429 ptyfs_modcmd(modcmd_t cmd, void *arg) 430 { 431 int error; 432 433 switch (cmd) { 434 case MODULE_CMD_INIT: 435 error = vfs_attach(&ptyfs_vfsops); 436 if (error != 0) 437 break; 438 sysctl_createv(&ptyfs_sysctl_log, 0, NULL, NULL, 439 CTLFLAG_PERMANENT, 440 CTLTYPE_NODE, "ptyfs", 441 SYSCTL_DESCR("Pty file system"), 442 NULL, 0, NULL, 0, 443 CTL_VFS, 23, CTL_EOL); 444 /* 445 * XXX the "23" above could be dynamic, thereby eliminating 446 * one more instance of the "number to vfs" mapping problem, 447 * but "23" is the order as taken from sys/mount.h 448 */ 449 break; 450 case MODULE_CMD_FINI: 451 error = vfs_detach(&ptyfs_vfsops); 452 if (error != 0) 453 break; 454 sysctl_teardown(&ptyfs_sysctl_log); 455 break; 456 default: 457 error = ENOTTY; 458 break; 459 } 460 461 return (error); 462 } 463