1 /* $NetBSD: ptyfs_subr.c,v 1.11 2007/12/08 19:29:44 pooka Exp $ */ 2 3 /* 4 * Copyright (c) 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed 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 * @(#)ptyfs_subr.c 8.6 (Berkeley) 5/14/95 35 */ 36 37 /* 38 * Copyright (c) 1994 Christopher G. Demetriou. All rights reserved. 39 * Copyright (c) 1993 Jan-Simon Pendry 40 * 41 * This code is derived from software contributed to Berkeley by 42 * Jan-Simon Pendry. 43 * 44 * Redistribution and use in source and binary forms, with or without 45 * modification, are permitted provided that the following conditions 46 * are met: 47 * 1. Redistributions of source code must retain the above copyright 48 * notice, this list of conditions and the following disclaimer. 49 * 2. Redistributions in binary form must reproduce the above copyright 50 * notice, this list of conditions and the following disclaimer in the 51 * documentation and/or other materials provided with the distribution. 52 * 3. All advertising materials mentioning features or use of this software 53 * must display the following acknowledgement: 54 * This product includes software developed by the University of 55 * California, Berkeley and its contributors. 56 * 4. Neither the name of the University nor the names of its contributors 57 * may be used to endorse or promote products derived from this software 58 * without specific prior written permission. 59 * 60 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 61 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 62 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 63 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 64 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 65 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 66 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 67 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 68 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 69 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 70 * SUCH DAMAGE. 71 * 72 * @(#)procfs_subr.c 8.6 (Berkeley) 5/14/95 73 */ 74 75 #include <sys/cdefs.h> 76 __KERNEL_RCSID(0, "$NetBSD: ptyfs_subr.c,v 1.11 2007/12/08 19:29:44 pooka Exp $"); 77 78 #include <sys/param.h> 79 #include <sys/systm.h> 80 #include <sys/time.h> 81 #include <sys/kernel.h> 82 #include <sys/vnode.h> 83 #include <sys/malloc.h> 84 #include <sys/stat.h> 85 #include <sys/file.h> 86 #include <sys/namei.h> 87 #include <sys/filedesc.h> 88 #include <sys/select.h> 89 #include <sys/tty.h> 90 #include <sys/pty.h> 91 #include <sys/kauth.h> 92 #include <sys/lwp.h> 93 94 #include <fs/ptyfs/ptyfs.h> 95 #include <miscfs/specfs/specdev.h> 96 97 static struct lock ptyfs_hashlock; 98 99 static LIST_HEAD(ptyfs_hashhead, ptyfsnode) *ptyfs_used_tbl, *ptyfs_free_tbl; 100 static u_long ptyfs_used_mask, ptyfs_free_mask; /* size of hash table - 1 */ 101 static kmutex_t ptyfs_used_slock, ptyfs_free_slock; 102 103 static void ptyfs_getinfo(struct ptyfsnode *, struct lwp *); 104 105 static void ptyfs_hashins(struct ptyfsnode *); 106 static void ptyfs_hashrem(struct ptyfsnode *); 107 108 static struct vnode *ptyfs_used_get(ptyfstype, int, struct mount *); 109 static struct ptyfsnode *ptyfs_free_get(ptyfstype, int, struct lwp *); 110 111 static void ptyfs_rehash(kmutex_t *, struct ptyfs_hashhead **, 112 u_long *); 113 114 #define PTYHASH(type, pty, mask) (PTYFS_FILENO(type, pty) % (mask + 1)) 115 116 117 static void 118 ptyfs_getinfo(struct ptyfsnode *ptyfs, struct lwp *l) 119 { 120 extern struct ptm_pty *ptyfs_save_ptm, ptm_ptyfspty; 121 122 if (ptyfs->ptyfs_type == PTYFSroot) { 123 ptyfs->ptyfs_mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP| 124 S_IROTH|S_IXOTH; 125 goto out; 126 } else 127 ptyfs->ptyfs_mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP| 128 S_IROTH|S_IWOTH; 129 130 if (ptyfs_save_ptm != NULL && ptyfs_save_ptm != &ptm_ptyfspty) { 131 int error; 132 struct nameidata nd; 133 char ttyname[64]; 134 kauth_cred_t cred; 135 struct vattr va; 136 /* 137 * We support traditional ptys, so we copy the info 138 * from the inode 139 */ 140 if ((error = (*ptyfs_save_ptm->makename)( 141 ptyfs_save_ptm, l, ttyname, sizeof(ttyname), 142 ptyfs->ptyfs_pty, ptyfs->ptyfs_type == PTYFSpts ? 't' 143 : 'p')) != 0) 144 goto out; 145 NDINIT(&nd, LOOKUP, NOFOLLOW|LOCKLEAF, UIO_SYSSPACE, ttyname); 146 if ((error = namei(&nd)) != 0) 147 goto out; 148 cred = kauth_cred_alloc(); 149 error = VOP_GETATTR(nd.ni_vp, &va, cred); 150 kauth_cred_free(cred); 151 VOP_UNLOCK(nd.ni_vp, 0); 152 vrele(nd.ni_vp); 153 if (error) 154 goto out; 155 ptyfs->ptyfs_uid = va.va_uid; 156 ptyfs->ptyfs_gid = va.va_gid; 157 ptyfs->ptyfs_mode = va.va_mode; 158 ptyfs->ptyfs_flags = va.va_flags; 159 ptyfs->ptyfs_birthtime = va.va_birthtime; 160 ptyfs->ptyfs_ctime = va.va_ctime; 161 ptyfs->ptyfs_mtime = va.va_mtime; 162 ptyfs->ptyfs_atime = va.va_atime; 163 return; 164 } 165 out: 166 ptyfs->ptyfs_uid = ptyfs->ptyfs_gid = 0; 167 ptyfs->ptyfs_flags |= PTYFS_CHANGE; 168 PTYFS_ITIMES(ptyfs, NULL, NULL, NULL); 169 ptyfs->ptyfs_birthtime = ptyfs->ptyfs_mtime = 170 ptyfs->ptyfs_atime = ptyfs->ptyfs_ctime; 171 ptyfs->ptyfs_flags = 0; 172 } 173 174 175 /* 176 * allocate a ptyfsnode/vnode pair. the vnode is 177 * referenced, and locked. 178 * 179 * the pid, ptyfs_type, and mount point uniquely 180 * identify a ptyfsnode. the mount point is needed 181 * because someone might mount this filesystem 182 * twice. 183 * 184 * all ptyfsnodes are maintained on a singly-linked 185 * list. new nodes are only allocated when they cannot 186 * be found on this list. entries on the list are 187 * removed when the vfs reclaim entry is called. 188 * 189 * a single lock is kept for the entire list. this is 190 * needed because the getnewvnode() function can block 191 * waiting for a vnode to become free, in which case there 192 * may be more than one ptyess trying to get the same 193 * vnode. this lock is only taken if we are going to 194 * call getnewvnode, since the kernel itself is single-threaded. 195 * 196 * if an entry is found on the list, then call vget() to 197 * take a reference. this is done because there may be 198 * zero references to it and so it needs to removed from 199 * the vnode free list. 200 */ 201 int 202 ptyfs_allocvp(struct mount *mp, struct vnode **vpp, ptyfstype type, int pty, 203 struct lwp *l) 204 { 205 struct ptyfsnode *ptyfs; 206 struct vnode *vp, *nvp; 207 int error; 208 209 do { 210 if ((*vpp = ptyfs_used_get(type, pty, mp)) != NULL) 211 return 0; 212 } while (lockmgr(&ptyfs_hashlock, LK_EXCLUSIVE|LK_SLEEPFAIL, 0)); 213 214 if ((error = getnewvnode(VT_PTYFS, mp, ptyfs_vnodeop_p, &vp)) != 0) { 215 *vpp = NULL; 216 lockmgr(&ptyfs_hashlock, LK_RELEASE, NULL); 217 return error; 218 } 219 220 vp->v_data = ptyfs = ptyfs_free_get(type, pty, l); 221 ptyfs->ptyfs_vnode = vp; 222 223 switch (type) { 224 case PTYFSroot: /* /pts = dr-xr-xr-x */ 225 vp->v_type = VDIR; 226 vp->v_vflag = VV_ROOT; 227 break; 228 229 case PTYFSpts: /* /pts/N = cxxxxxxxxx */ 230 case PTYFSptc: /* controlling side = cxxxxxxxxx */ 231 vp->v_type = VCHR; 232 if ((nvp = checkalias(vp, PTYFS_MAKEDEV(ptyfs), mp)) != NULL) { 233 /* 234 * Discard unneeded vnode, but save its inode. 235 */ 236 nvp->v_data = vp->v_data; 237 vp->v_data = NULL; 238 /* XXX spec_vnodeops has no locking, do it explicitly */ 239 vp->v_vflag &= ~VV_LOCKSWORK; 240 VOP_UNLOCK(vp, 0); 241 vp->v_op = spec_vnodeop_p; 242 vrele(vp); 243 vgone(vp); 244 lockmgr(&nvp->v_lock, LK_EXCLUSIVE, &nvp->v_interlock); 245 /* 246 * Reinitialize aliased inode. 247 */ 248 vp = nvp; 249 ptyfs->ptyfs_vnode = vp; 250 } 251 break; 252 default: 253 panic("ptyfs_allocvp"); 254 } 255 256 ptyfs_hashins(ptyfs); 257 uvm_vnp_setsize(vp, 0); 258 lockmgr(&ptyfs_hashlock, LK_RELEASE, NULL); 259 260 *vpp = vp; 261 return 0; 262 } 263 264 int 265 ptyfs_freevp(struct vnode *vp) 266 { 267 struct ptyfsnode *ptyfs = VTOPTYFS(vp); 268 269 ptyfs_hashrem(ptyfs); 270 vp->v_data = NULL; 271 return 0; 272 } 273 274 /* 275 * Initialize ptyfsnode hash table. 276 */ 277 void 278 ptyfs_hashinit(void) 279 { 280 lockinit(&ptyfs_hashlock, PINOD, "ptyfs_hashlock", 0, 0); 281 ptyfs_used_tbl = hashinit(desiredvnodes / 4, HASH_LIST, M_UFSMNT, 282 M_WAITOK, &ptyfs_used_mask); 283 ptyfs_free_tbl = hashinit(desiredvnodes / 4, HASH_LIST, M_UFSMNT, 284 M_WAITOK, &ptyfs_free_mask); 285 mutex_init(&ptyfs_used_slock, MUTEX_DEFAULT, IPL_NONE); 286 mutex_init(&ptyfs_free_slock, MUTEX_DEFAULT, IPL_NONE); 287 } 288 289 void 290 ptyfs_hashreinit(void) 291 { 292 ptyfs_rehash(&ptyfs_used_slock, &ptyfs_used_tbl, &ptyfs_used_mask); 293 ptyfs_rehash(&ptyfs_free_slock, &ptyfs_free_tbl, &ptyfs_free_mask); 294 } 295 296 static void 297 ptyfs_rehash(kmutex_t *hlock, struct ptyfs_hashhead **hhead, 298 u_long *hmask) 299 { 300 struct ptyfsnode *pp; 301 struct ptyfs_hashhead *oldhash, *hash; 302 u_long i, oldmask, mask, val; 303 304 hash = hashinit(desiredvnodes / 4, HASH_LIST, M_UFSMNT, M_WAITOK, 305 &mask); 306 307 mutex_enter(hlock); 308 oldhash = *hhead; 309 oldmask = *hmask; 310 *hhead = hash; 311 *hmask = mask; 312 for (i = 0; i <= oldmask; i++) { 313 while ((pp = LIST_FIRST(&oldhash[i])) != NULL) { 314 LIST_REMOVE(pp, ptyfs_hash); 315 val = PTYHASH(pp->ptyfs_type, pp->ptyfs_pty, 316 ptyfs_used_mask); 317 LIST_INSERT_HEAD(&hash[val], pp, ptyfs_hash); 318 } 319 } 320 mutex_exit(hlock); 321 hashdone(oldhash, M_UFSMNT); 322 } 323 324 /* 325 * Free ptyfsnode hash table. 326 */ 327 void 328 ptyfs_hashdone(void) 329 { 330 hashdone(ptyfs_used_tbl, M_UFSMNT); 331 hashdone(ptyfs_free_tbl, M_UFSMNT); 332 } 333 334 /* 335 * Get a ptyfsnode from the free table, or allocate one. 336 * Removes the node from the free table. 337 */ 338 struct ptyfsnode * 339 ptyfs_free_get(ptyfstype type, int pty, struct lwp *l) 340 { 341 struct ptyfs_hashhead *ppp; 342 struct ptyfsnode *pp; 343 344 mutex_enter(&ptyfs_free_slock); 345 ppp = &ptyfs_free_tbl[PTYHASH(type, pty, ptyfs_free_mask)]; 346 LIST_FOREACH(pp, ppp, ptyfs_hash) { 347 if (pty == pp->ptyfs_pty && pp->ptyfs_type == type) { 348 LIST_REMOVE(pp, ptyfs_hash); 349 mutex_exit(&ptyfs_free_slock); 350 return pp; 351 } 352 } 353 mutex_exit(&ptyfs_free_slock); 354 355 MALLOC(pp, void *, sizeof(struct ptyfsnode), M_TEMP, M_WAITOK); 356 pp->ptyfs_pty = pty; 357 pp->ptyfs_type = type; 358 pp->ptyfs_fileno = PTYFS_FILENO(pty, type); 359 ptyfs_getinfo(pp, l); 360 return pp; 361 } 362 363 struct vnode * 364 ptyfs_used_get(ptyfstype type, int pty, struct mount *mp) 365 { 366 struct ptyfs_hashhead *ppp; 367 struct ptyfsnode *pp; 368 struct vnode *vp; 369 370 loop: 371 mutex_enter(&ptyfs_used_slock); 372 ppp = &ptyfs_used_tbl[PTYHASH(type, pty, ptyfs_used_mask)]; 373 LIST_FOREACH(pp, ppp, ptyfs_hash) { 374 vp = PTYFSTOV(pp); 375 if (pty == pp->ptyfs_pty && pp->ptyfs_type == type && 376 vp->v_mount == mp) { 377 simple_lock(&vp->v_interlock); 378 mutex_exit(&ptyfs_used_slock); 379 if (vget(vp, LK_EXCLUSIVE | LK_INTERLOCK)) 380 goto loop; 381 return vp; 382 } 383 } 384 mutex_exit(&ptyfs_used_slock); 385 return NULL; 386 } 387 388 /* 389 * Insert the ptyfsnode into the used table and lock it. 390 */ 391 static void 392 ptyfs_hashins(struct ptyfsnode *pp) 393 { 394 struct ptyfs_hashhead *ppp; 395 396 /* lock the ptyfsnode, then put it on the appropriate hash list */ 397 lockmgr(&pp->ptyfs_vnode->v_lock, LK_EXCLUSIVE, NULL); 398 399 mutex_enter(&ptyfs_used_slock); 400 ppp = &ptyfs_used_tbl[PTYHASH(pp->ptyfs_type, pp->ptyfs_pty, 401 ptyfs_used_mask)]; 402 LIST_INSERT_HEAD(ppp, pp, ptyfs_hash); 403 mutex_exit(&ptyfs_used_slock); 404 } 405 406 /* 407 * Remove the ptyfsnode from the used table, and add it to the free table 408 */ 409 static void 410 ptyfs_hashrem(struct ptyfsnode *pp) 411 { 412 struct ptyfs_hashhead *ppp; 413 414 mutex_enter(&ptyfs_used_slock); 415 LIST_REMOVE(pp, ptyfs_hash); 416 mutex_exit(&ptyfs_used_slock); 417 418 mutex_enter(&ptyfs_free_slock); 419 ppp = &ptyfs_free_tbl[PTYHASH(pp->ptyfs_type, pp->ptyfs_pty, 420 ptyfs_free_mask)]; 421 LIST_INSERT_HEAD(ppp, pp, ptyfs_hash); 422 mutex_exit(&ptyfs_free_slock); 423 } 424