1 /* $NetBSD: ptyfs_subr.c,v 1.5 2005/12/11 12:24:29 christos 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 1.5 2005/12/11 12:24:29 christos 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 92 #include <fs/ptyfs/ptyfs.h> 93 #include <miscfs/specfs/specdev.h> 94 95 static struct lock ptyfs_hashlock; 96 97 static LIST_HEAD(ptyfs_hashhead, ptyfsnode) *ptyfs_used_tbl, *ptyfs_free_tbl; 98 static u_long ptyfs_used_mask, ptyfs_free_mask; /* size of hash table - 1 */ 99 static struct simplelock ptyfs_used_slock, ptyfs_free_slock; 100 101 static void ptyfs_getinfo(struct ptyfsnode *, struct lwp *); 102 103 static void ptyfs_hashins(struct ptyfsnode *); 104 static void ptyfs_hashrem(struct ptyfsnode *); 105 106 static struct vnode *ptyfs_used_get(ptyfstype, int, struct mount *); 107 static struct ptyfsnode *ptyfs_free_get(ptyfstype, int, struct lwp *); 108 109 static void ptyfs_rehash(struct simplelock *, struct ptyfs_hashhead **, 110 u_long *); 111 112 #define PTYHASH(type, pty, mask) (PTYFS_FILENO(type, pty) % (mask + 1)) 113 114 115 static void 116 ptyfs_getinfo(struct ptyfsnode *ptyfs, struct lwp *l) 117 { 118 extern struct ptm_pty *ptyfs_save_ptm, ptm_ptyfspty; 119 120 if (ptyfs->ptyfs_type == PTYFSroot) { 121 ptyfs->ptyfs_mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP| 122 S_IROTH|S_IXOTH; 123 goto out; 124 } else 125 ptyfs->ptyfs_mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP| 126 S_IROTH|S_IWOTH; 127 128 if (ptyfs_save_ptm != NULL && ptyfs_save_ptm != &ptm_ptyfspty) { 129 int error; 130 struct nameidata nd; 131 char ttyname[64]; 132 struct ucred *cred; 133 struct vattr va; 134 /* 135 * We support traditional ptys, so we copy the info 136 * from the inode 137 */ 138 if ((error = (*ptyfs_save_ptm->makename)( 139 ptyfs_save_ptm, ttyname, sizeof(ttyname), 140 ptyfs->ptyfs_pty, ptyfs->ptyfs_type == PTYFSpts ? 't' 141 : 'p')) != 0) 142 goto out; 143 NDINIT(&nd, LOOKUP, NOFOLLOW|LOCKLEAF, UIO_SYSSPACE, ttyname, 144 l); 145 if ((error = namei(&nd)) != 0) 146 goto out; 147 cred = crget(); 148 error = VOP_GETATTR(nd.ni_vp, &va, cred, l); 149 crfree(cred); 150 VOP_UNLOCK(nd.ni_vp, 0); 151 vrele(nd.ni_vp); 152 if (error) 153 goto out; 154 ptyfs->ptyfs_uid = va.va_uid; 155 ptyfs->ptyfs_gid = va.va_gid; 156 ptyfs->ptyfs_mode = va.va_mode; 157 ptyfs->ptyfs_flags = va.va_flags; 158 ptyfs->ptyfs_birthtime = va.va_birthtime; 159 ptyfs->ptyfs_ctime = va.va_ctime; 160 ptyfs->ptyfs_mtime = va.va_mtime; 161 ptyfs->ptyfs_atime = va.va_atime; 162 return; 163 } 164 out: 165 ptyfs->ptyfs_uid = ptyfs->ptyfs_gid = 0; 166 ptyfs->ptyfs_flags |= PTYFS_CHANGE; 167 PTYFS_ITIMES(ptyfs, NULL, NULL, NULL); 168 ptyfs->ptyfs_birthtime = ptyfs->ptyfs_mtime = 169 ptyfs->ptyfs_atime = ptyfs->ptyfs_ctime; 170 ptyfs->ptyfs_flags = 0; 171 } 172 173 174 /* 175 * allocate a ptyfsnode/vnode pair. the vnode is 176 * referenced, and locked. 177 * 178 * the pid, ptyfs_type, and mount point uniquely 179 * identify a ptyfsnode. the mount point is needed 180 * because someone might mount this filesystem 181 * twice. 182 * 183 * all ptyfsnodes are maintained on a singly-linked 184 * list. new nodes are only allocated when they cannot 185 * be found on this list. entries on the list are 186 * removed when the vfs reclaim entry is called. 187 * 188 * a single lock is kept for the entire list. this is 189 * needed because the getnewvnode() function can block 190 * waiting for a vnode to become free, in which case there 191 * may be more than one ptyess trying to get the same 192 * vnode. this lock is only taken if we are going to 193 * call getnewvnode, since the kernel itself is single-threaded. 194 * 195 * if an entry is found on the list, then call vget() to 196 * take a reference. this is done because there may be 197 * zero references to it and so it needs to removed from 198 * the vnode free list. 199 */ 200 int 201 ptyfs_allocvp(struct mount *mp, struct vnode **vpp, ptyfstype type, int pty, 202 struct lwp *l) 203 { 204 struct ptyfsnode *ptyfs; 205 struct vnode *vp, *nvp; 206 int error; 207 208 do { 209 if ((*vpp = ptyfs_used_get(type, pty, mp)) != NULL) 210 return 0; 211 } while (lockmgr(&ptyfs_hashlock, LK_EXCLUSIVE|LK_SLEEPFAIL, 0)); 212 213 if ((error = getnewvnode(VT_PTYFS, mp, ptyfs_vnodeop_p, &vp)) != 0) { 214 *vpp = NULL; 215 lockmgr(&ptyfs_hashlock, LK_RELEASE, NULL); 216 return error; 217 } 218 219 vp->v_data = ptyfs = ptyfs_free_get(type, pty, l); 220 ptyfs->ptyfs_vnode = vp; 221 222 switch (type) { 223 case PTYFSroot: /* /pts = dr-xr-xr-x */ 224 vp->v_type = VDIR; 225 vp->v_flag = VROOT; 226 break; 227 228 case PTYFSpts: /* /pts/N = cxxxxxxxxx */ 229 case PTYFSptc: /* controlling side = cxxxxxxxxx */ 230 vp->v_type = VCHR; 231 if ((nvp = checkalias(vp, PTYFS_MAKEDEV(ptyfs), mp)) != NULL) { 232 /* 233 * Discard unneeded vnode, but save its inode. 234 */ 235 nvp->v_data = vp->v_data; 236 vp->v_data = NULL; 237 /* XXX spec_vnodeops has no locking, do it explicitly */ 238 VOP_UNLOCK(vp, 0); 239 vp->v_op = spec_vnodeop_p; 240 vp->v_flag &= ~VLOCKSWORK; 241 vrele(vp); 242 vgone(vp); 243 lockmgr(&nvp->v_lock, LK_EXCLUSIVE, &nvp->v_interlock); 244 /* 245 * Reinitialize aliased inode. 246 */ 247 vp = nvp; 248 ptyfs->ptyfs_vnode = vp; 249 } 250 break; 251 default: 252 panic("ptyfs_allocvp"); 253 } 254 255 ptyfs_hashins(ptyfs); 256 uvm_vnp_setsize(vp, 0); 257 lockmgr(&ptyfs_hashlock, LK_RELEASE, NULL); 258 259 *vpp = vp; 260 return 0; 261 } 262 263 int 264 ptyfs_freevp(struct vnode *vp) 265 { 266 struct ptyfsnode *ptyfs = VTOPTYFS(vp); 267 268 ptyfs_hashrem(ptyfs); 269 vp->v_data = NULL; 270 return 0; 271 } 272 273 /* 274 * Initialize ptyfsnode hash table. 275 */ 276 void 277 ptyfs_hashinit(void) 278 { 279 lockinit(&ptyfs_hashlock, PINOD, "ptyfs_hashlock", 0, 0); 280 ptyfs_used_tbl = hashinit(desiredvnodes / 4, HASH_LIST, M_UFSMNT, 281 M_WAITOK, &ptyfs_used_mask); 282 ptyfs_free_tbl = hashinit(desiredvnodes / 4, HASH_LIST, M_UFSMNT, 283 M_WAITOK, &ptyfs_free_mask); 284 simple_lock_init(&ptyfs_used_slock); 285 simple_lock_init(&ptyfs_free_slock); 286 } 287 288 void 289 ptyfs_hashreinit(void) 290 { 291 ptyfs_rehash(&ptyfs_used_slock, &ptyfs_used_tbl, &ptyfs_used_mask); 292 ptyfs_rehash(&ptyfs_free_slock, &ptyfs_free_tbl, &ptyfs_free_mask); 293 } 294 295 static void 296 ptyfs_rehash(struct simplelock *hlock, struct ptyfs_hashhead **hhead, 297 u_long *hmask) 298 { 299 struct ptyfsnode *pp; 300 struct ptyfs_hashhead *oldhash, *hash; 301 u_long i, oldmask, mask, val; 302 303 hash = hashinit(desiredvnodes / 4, HASH_LIST, M_UFSMNT, M_WAITOK, 304 &mask); 305 306 simple_lock(hlock); 307 oldhash = *hhead; 308 oldmask = *hmask; 309 *hhead = hash; 310 *hmask = mask; 311 for (i = 0; i <= oldmask; i++) { 312 while ((pp = LIST_FIRST(&oldhash[i])) != NULL) { 313 LIST_REMOVE(pp, ptyfs_hash); 314 val = PTYHASH(pp->ptyfs_type, pp->ptyfs_pty, 315 ptyfs_used_mask); 316 LIST_INSERT_HEAD(&hash[val], pp, ptyfs_hash); 317 } 318 } 319 simple_unlock(hlock); 320 hashdone(oldhash, M_UFSMNT); 321 } 322 323 /* 324 * Free ptyfsnode hash table. 325 */ 326 void 327 ptyfs_hashdone(void) 328 { 329 hashdone(ptyfs_used_tbl, M_UFSMNT); 330 hashdone(ptyfs_free_tbl, M_UFSMNT); 331 } 332 333 /* 334 * Get a ptyfsnode from the free table, or allocate one. 335 * Removes the node from the free table. 336 */ 337 struct ptyfsnode * 338 ptyfs_free_get(ptyfstype type, int pty, struct lwp *l) 339 { 340 struct ptyfs_hashhead *ppp; 341 struct ptyfsnode *pp; 342 343 simple_lock(&ptyfs_free_slock); 344 ppp = &ptyfs_free_tbl[PTYHASH(type, pty, ptyfs_free_mask)]; 345 LIST_FOREACH(pp, ppp, ptyfs_hash) { 346 if (pty == pp->ptyfs_pty && pp->ptyfs_type == type) { 347 LIST_REMOVE(pp, ptyfs_hash); 348 simple_unlock(&ptyfs_free_slock); 349 return pp; 350 } 351 } 352 simple_unlock(&ptyfs_free_slock); 353 354 MALLOC(pp, void *, sizeof(struct ptyfsnode), M_TEMP, M_WAITOK); 355 pp->ptyfs_pty = pty; 356 pp->ptyfs_type = type; 357 pp->ptyfs_fileno = PTYFS_FILENO(pty, type); 358 ptyfs_getinfo(pp, l); 359 return pp; 360 } 361 362 struct vnode * 363 ptyfs_used_get(ptyfstype type, int pty, struct mount *mp) 364 { 365 struct ptyfs_hashhead *ppp; 366 struct ptyfsnode *pp; 367 struct vnode *vp; 368 369 loop: 370 simple_lock(&ptyfs_used_slock); 371 ppp = &ptyfs_used_tbl[PTYHASH(type, pty, ptyfs_used_mask)]; 372 LIST_FOREACH(pp, ppp, ptyfs_hash) { 373 vp = PTYFSTOV(pp); 374 if (pty == pp->ptyfs_pty && pp->ptyfs_type == type && 375 vp->v_mount == mp) { 376 simple_lock(&vp->v_interlock); 377 simple_unlock(&ptyfs_used_slock); 378 if (vget(vp, LK_EXCLUSIVE | LK_INTERLOCK)) 379 goto loop; 380 return vp; 381 } 382 } 383 simple_unlock(&ptyfs_used_slock); 384 return NULL; 385 } 386 387 /* 388 * Insert the ptyfsnode into the used table and lock it. 389 */ 390 static void 391 ptyfs_hashins(struct ptyfsnode *pp) 392 { 393 struct ptyfs_hashhead *ppp; 394 395 /* lock the ptyfsnode, then put it on the appropriate hash list */ 396 lockmgr(&pp->ptyfs_vnode->v_lock, LK_EXCLUSIVE, NULL); 397 398 simple_lock(&ptyfs_used_slock); 399 ppp = &ptyfs_used_tbl[PTYHASH(pp->ptyfs_type, pp->ptyfs_pty, 400 ptyfs_used_mask)]; 401 LIST_INSERT_HEAD(ppp, pp, ptyfs_hash); 402 simple_unlock(&ptyfs_used_slock); 403 } 404 405 /* 406 * Remove the ptyfsnode from the used table, and add it to the free table 407 */ 408 static void 409 ptyfs_hashrem(struct ptyfsnode *pp) 410 { 411 struct ptyfs_hashhead *ppp; 412 413 simple_lock(&ptyfs_used_slock); 414 LIST_REMOVE(pp, ptyfs_hash); 415 simple_unlock(&ptyfs_used_slock); 416 417 simple_lock(&ptyfs_free_slock); 418 ppp = &ptyfs_free_tbl[PTYHASH(pp->ptyfs_type, pp->ptyfs_pty, 419 ptyfs_free_mask)]; 420 LIST_INSERT_HEAD(ppp, pp, ptyfs_hash); 421 simple_unlock(&ptyfs_free_slock); 422 } 423