1 /* $NetBSD: ptyfs_subr.c,v 1.9 2007/10/10 20:42:24 ad 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 1.9 2007/10/10 20:42:24 ad 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 l); 147 if ((error = namei(&nd)) != 0) 148 goto out; 149 cred = kauth_cred_alloc(); 150 error = VOP_GETATTR(nd.ni_vp, &va, cred, l); 151 kauth_cred_free(cred); 152 VOP_UNLOCK(nd.ni_vp, 0); 153 vrele(nd.ni_vp); 154 if (error) 155 goto out; 156 ptyfs->ptyfs_uid = va.va_uid; 157 ptyfs->ptyfs_gid = va.va_gid; 158 ptyfs->ptyfs_mode = va.va_mode; 159 ptyfs->ptyfs_flags = va.va_flags; 160 ptyfs->ptyfs_birthtime = va.va_birthtime; 161 ptyfs->ptyfs_ctime = va.va_ctime; 162 ptyfs->ptyfs_mtime = va.va_mtime; 163 ptyfs->ptyfs_atime = va.va_atime; 164 return; 165 } 166 out: 167 ptyfs->ptyfs_uid = ptyfs->ptyfs_gid = 0; 168 ptyfs->ptyfs_flags |= PTYFS_CHANGE; 169 PTYFS_ITIMES(ptyfs, NULL, NULL, NULL); 170 ptyfs->ptyfs_birthtime = ptyfs->ptyfs_mtime = 171 ptyfs->ptyfs_atime = ptyfs->ptyfs_ctime; 172 ptyfs->ptyfs_flags = 0; 173 } 174 175 176 /* 177 * allocate a ptyfsnode/vnode pair. the vnode is 178 * referenced, and locked. 179 * 180 * the pid, ptyfs_type, and mount point uniquely 181 * identify a ptyfsnode. the mount point is needed 182 * because someone might mount this filesystem 183 * twice. 184 * 185 * all ptyfsnodes are maintained on a singly-linked 186 * list. new nodes are only allocated when they cannot 187 * be found on this list. entries on the list are 188 * removed when the vfs reclaim entry is called. 189 * 190 * a single lock is kept for the entire list. this is 191 * needed because the getnewvnode() function can block 192 * waiting for a vnode to become free, in which case there 193 * may be more than one ptyess trying to get the same 194 * vnode. this lock is only taken if we are going to 195 * call getnewvnode, since the kernel itself is single-threaded. 196 * 197 * if an entry is found on the list, then call vget() to 198 * take a reference. this is done because there may be 199 * zero references to it and so it needs to removed from 200 * the vnode free list. 201 */ 202 int 203 ptyfs_allocvp(struct mount *mp, struct vnode **vpp, ptyfstype type, int pty, 204 struct lwp *l) 205 { 206 struct ptyfsnode *ptyfs; 207 struct vnode *vp, *nvp; 208 int error; 209 210 do { 211 if ((*vpp = ptyfs_used_get(type, pty, mp)) != NULL) 212 return 0; 213 } while (lockmgr(&ptyfs_hashlock, LK_EXCLUSIVE|LK_SLEEPFAIL, 0)); 214 215 if ((error = getnewvnode(VT_PTYFS, mp, ptyfs_vnodeop_p, &vp)) != 0) { 216 *vpp = NULL; 217 lockmgr(&ptyfs_hashlock, LK_RELEASE, NULL); 218 return error; 219 } 220 221 vp->v_data = ptyfs = ptyfs_free_get(type, pty, l); 222 ptyfs->ptyfs_vnode = vp; 223 224 switch (type) { 225 case PTYFSroot: /* /pts = dr-xr-xr-x */ 226 vp->v_type = VDIR; 227 vp->v_vflag = VV_ROOT; 228 break; 229 230 case PTYFSpts: /* /pts/N = cxxxxxxxxx */ 231 case PTYFSptc: /* controlling side = cxxxxxxxxx */ 232 vp->v_type = VCHR; 233 if ((nvp = checkalias(vp, PTYFS_MAKEDEV(ptyfs), mp)) != NULL) { 234 /* 235 * Discard unneeded vnode, but save its inode. 236 */ 237 nvp->v_data = vp->v_data; 238 vp->v_data = NULL; 239 /* XXX spec_vnodeops has no locking, do it explicitly */ 240 vp->v_vflag &= ~VV_LOCKSWORK; 241 VOP_UNLOCK(vp, 0); 242 vp->v_op = spec_vnodeop_p; 243 vrele(vp); 244 vgone(vp); 245 lockmgr(&nvp->v_lock, LK_EXCLUSIVE, &nvp->v_interlock); 246 /* 247 * Reinitialize aliased inode. 248 */ 249 vp = nvp; 250 ptyfs->ptyfs_vnode = vp; 251 } 252 break; 253 default: 254 panic("ptyfs_allocvp"); 255 } 256 257 ptyfs_hashins(ptyfs); 258 uvm_vnp_setsize(vp, 0); 259 lockmgr(&ptyfs_hashlock, LK_RELEASE, NULL); 260 261 *vpp = vp; 262 return 0; 263 } 264 265 int 266 ptyfs_freevp(struct vnode *vp) 267 { 268 struct ptyfsnode *ptyfs = VTOPTYFS(vp); 269 270 ptyfs_hashrem(ptyfs); 271 vp->v_data = NULL; 272 return 0; 273 } 274 275 /* 276 * Initialize ptyfsnode hash table. 277 */ 278 void 279 ptyfs_hashinit(void) 280 { 281 lockinit(&ptyfs_hashlock, PINOD, "ptyfs_hashlock", 0, 0); 282 ptyfs_used_tbl = hashinit(desiredvnodes / 4, HASH_LIST, M_UFSMNT, 283 M_WAITOK, &ptyfs_used_mask); 284 ptyfs_free_tbl = hashinit(desiredvnodes / 4, HASH_LIST, M_UFSMNT, 285 M_WAITOK, &ptyfs_free_mask); 286 mutex_init(&ptyfs_used_slock, MUTEX_DEFAULT, IPL_NONE); 287 mutex_init(&ptyfs_free_slock, MUTEX_DEFAULT, IPL_NONE); 288 } 289 290 void 291 ptyfs_hashreinit(void) 292 { 293 ptyfs_rehash(&ptyfs_used_slock, &ptyfs_used_tbl, &ptyfs_used_mask); 294 ptyfs_rehash(&ptyfs_free_slock, &ptyfs_free_tbl, &ptyfs_free_mask); 295 } 296 297 static void 298 ptyfs_rehash(kmutex_t *hlock, struct ptyfs_hashhead **hhead, 299 u_long *hmask) 300 { 301 struct ptyfsnode *pp; 302 struct ptyfs_hashhead *oldhash, *hash; 303 u_long i, oldmask, mask, val; 304 305 hash = hashinit(desiredvnodes / 4, HASH_LIST, M_UFSMNT, M_WAITOK, 306 &mask); 307 308 mutex_enter(hlock); 309 oldhash = *hhead; 310 oldmask = *hmask; 311 *hhead = hash; 312 *hmask = mask; 313 for (i = 0; i <= oldmask; i++) { 314 while ((pp = LIST_FIRST(&oldhash[i])) != NULL) { 315 LIST_REMOVE(pp, ptyfs_hash); 316 val = PTYHASH(pp->ptyfs_type, pp->ptyfs_pty, 317 ptyfs_used_mask); 318 LIST_INSERT_HEAD(&hash[val], pp, ptyfs_hash); 319 } 320 } 321 mutex_exit(hlock); 322 hashdone(oldhash, M_UFSMNT); 323 } 324 325 /* 326 * Free ptyfsnode hash table. 327 */ 328 void 329 ptyfs_hashdone(void) 330 { 331 hashdone(ptyfs_used_tbl, M_UFSMNT); 332 hashdone(ptyfs_free_tbl, M_UFSMNT); 333 } 334 335 /* 336 * Get a ptyfsnode from the free table, or allocate one. 337 * Removes the node from the free table. 338 */ 339 struct ptyfsnode * 340 ptyfs_free_get(ptyfstype type, int pty, struct lwp *l) 341 { 342 struct ptyfs_hashhead *ppp; 343 struct ptyfsnode *pp; 344 345 mutex_enter(&ptyfs_free_slock); 346 ppp = &ptyfs_free_tbl[PTYHASH(type, pty, ptyfs_free_mask)]; 347 LIST_FOREACH(pp, ppp, ptyfs_hash) { 348 if (pty == pp->ptyfs_pty && pp->ptyfs_type == type) { 349 LIST_REMOVE(pp, ptyfs_hash); 350 mutex_exit(&ptyfs_free_slock); 351 return pp; 352 } 353 } 354 mutex_exit(&ptyfs_free_slock); 355 356 MALLOC(pp, void *, sizeof(struct ptyfsnode), M_TEMP, M_WAITOK); 357 pp->ptyfs_pty = pty; 358 pp->ptyfs_type = type; 359 pp->ptyfs_fileno = PTYFS_FILENO(pty, type); 360 ptyfs_getinfo(pp, l); 361 return pp; 362 } 363 364 struct vnode * 365 ptyfs_used_get(ptyfstype type, int pty, struct mount *mp) 366 { 367 struct ptyfs_hashhead *ppp; 368 struct ptyfsnode *pp; 369 struct vnode *vp; 370 371 loop: 372 mutex_enter(&ptyfs_used_slock); 373 ppp = &ptyfs_used_tbl[PTYHASH(type, pty, ptyfs_used_mask)]; 374 LIST_FOREACH(pp, ppp, ptyfs_hash) { 375 vp = PTYFSTOV(pp); 376 if (pty == pp->ptyfs_pty && pp->ptyfs_type == type && 377 vp->v_mount == mp) { 378 simple_lock(&vp->v_interlock); 379 mutex_exit(&ptyfs_used_slock); 380 if (vget(vp, LK_EXCLUSIVE | LK_INTERLOCK)) 381 goto loop; 382 return vp; 383 } 384 } 385 mutex_exit(&ptyfs_used_slock); 386 return NULL; 387 } 388 389 /* 390 * Insert the ptyfsnode into the used table and lock it. 391 */ 392 static void 393 ptyfs_hashins(struct ptyfsnode *pp) 394 { 395 struct ptyfs_hashhead *ppp; 396 397 /* lock the ptyfsnode, then put it on the appropriate hash list */ 398 lockmgr(&pp->ptyfs_vnode->v_lock, LK_EXCLUSIVE, NULL); 399 400 mutex_enter(&ptyfs_used_slock); 401 ppp = &ptyfs_used_tbl[PTYHASH(pp->ptyfs_type, pp->ptyfs_pty, 402 ptyfs_used_mask)]; 403 LIST_INSERT_HEAD(ppp, pp, ptyfs_hash); 404 mutex_exit(&ptyfs_used_slock); 405 } 406 407 /* 408 * Remove the ptyfsnode from the used table, and add it to the free table 409 */ 410 static void 411 ptyfs_hashrem(struct ptyfsnode *pp) 412 { 413 struct ptyfs_hashhead *ppp; 414 415 mutex_enter(&ptyfs_used_slock); 416 LIST_REMOVE(pp, ptyfs_hash); 417 mutex_exit(&ptyfs_used_slock); 418 419 mutex_enter(&ptyfs_free_slock); 420 ppp = &ptyfs_free_tbl[PTYHASH(pp->ptyfs_type, pp->ptyfs_pty, 421 ptyfs_free_mask)]; 422 LIST_INSERT_HEAD(ppp, pp, ptyfs_hash); 423 mutex_exit(&ptyfs_free_slock); 424 } 425