1 /*- 2 * Copyright (c) 2002, Jeffrey Roberson <jeff@freebsd.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice unmodified, this list of conditions, and the following 10 * disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include "opt_mac.h" 31 32 #include <sys/param.h> 33 #include <sys/systm.h> 34 #include <sys/kernel.h> 35 #include <sys/kthread.h> 36 #include <sys/lock.h> 37 #include <sys/mount.h> 38 #include <sys/mutex.h> 39 #include <sys/namei.h> 40 #include <sys/proc.h> 41 #include <sys/vnode.h> 42 #include <sys/alq.h> 43 #include <sys/malloc.h> 44 #include <sys/unistd.h> 45 #include <sys/fcntl.h> 46 #include <sys/eventhandler.h> 47 48 #include <security/mac/mac_framework.h> 49 50 /* Async. Logging Queue */ 51 struct alq { 52 int aq_entmax; /* Max entries */ 53 int aq_entlen; /* Entry length */ 54 char *aq_entbuf; /* Buffer for stored entries */ 55 int aq_flags; /* Queue flags */ 56 struct mtx aq_mtx; /* Queue lock */ 57 struct vnode *aq_vp; /* Open vnode handle */ 58 struct ucred *aq_cred; /* Credentials of the opening thread */ 59 struct ale *aq_first; /* First ent */ 60 struct ale *aq_entfree; /* First free ent */ 61 struct ale *aq_entvalid; /* First ent valid for writing */ 62 LIST_ENTRY(alq) aq_act; /* List of active queues */ 63 LIST_ENTRY(alq) aq_link; /* List of all queues */ 64 }; 65 66 #define AQ_WANTED 0x0001 /* Wakeup sleeper when io is done */ 67 #define AQ_ACTIVE 0x0002 /* on the active list */ 68 #define AQ_FLUSHING 0x0004 /* doing IO */ 69 #define AQ_SHUTDOWN 0x0008 /* Queue no longer valid */ 70 71 #define ALQ_LOCK(alq) mtx_lock_spin(&(alq)->aq_mtx) 72 #define ALQ_UNLOCK(alq) mtx_unlock_spin(&(alq)->aq_mtx) 73 74 static MALLOC_DEFINE(M_ALD, "ALD", "ALD"); 75 76 /* 77 * The ald_mtx protects the ald_queues list and the ald_active list. 78 */ 79 static struct mtx ald_mtx; 80 static LIST_HEAD(, alq) ald_queues; 81 static LIST_HEAD(, alq) ald_active; 82 static int ald_shutingdown = 0; 83 struct thread *ald_thread; 84 static struct proc *ald_proc; 85 86 #define ALD_LOCK() mtx_lock(&ald_mtx) 87 #define ALD_UNLOCK() mtx_unlock(&ald_mtx) 88 89 /* Daemon functions */ 90 static int ald_add(struct alq *); 91 static int ald_rem(struct alq *); 92 static void ald_startup(void *); 93 static void ald_daemon(void); 94 static void ald_shutdown(void *, int); 95 static void ald_activate(struct alq *); 96 static void ald_deactivate(struct alq *); 97 98 /* Internal queue functions */ 99 static void alq_shutdown(struct alq *); 100 static int alq_doio(struct alq *); 101 102 103 /* 104 * Add a new queue to the global list. Fail if we're shutting down. 105 */ 106 static int 107 ald_add(struct alq *alq) 108 { 109 int error; 110 111 error = 0; 112 113 ALD_LOCK(); 114 if (ald_shutingdown) { 115 error = EBUSY; 116 goto done; 117 } 118 LIST_INSERT_HEAD(&ald_queues, alq, aq_link); 119 done: 120 ALD_UNLOCK(); 121 return (error); 122 } 123 124 /* 125 * Remove a queue from the global list unless we're shutting down. If so, 126 * the ald will take care of cleaning up it's resources. 127 */ 128 static int 129 ald_rem(struct alq *alq) 130 { 131 int error; 132 133 error = 0; 134 135 ALD_LOCK(); 136 if (ald_shutingdown) { 137 error = EBUSY; 138 goto done; 139 } 140 LIST_REMOVE(alq, aq_link); 141 done: 142 ALD_UNLOCK(); 143 return (error); 144 } 145 146 /* 147 * Put a queue on the active list. This will schedule it for writing. 148 */ 149 static void 150 ald_activate(struct alq *alq) 151 { 152 LIST_INSERT_HEAD(&ald_active, alq, aq_act); 153 wakeup(&ald_active); 154 } 155 156 static void 157 ald_deactivate(struct alq *alq) 158 { 159 LIST_REMOVE(alq, aq_act); 160 alq->aq_flags &= ~AQ_ACTIVE; 161 } 162 163 static void 164 ald_startup(void *unused) 165 { 166 mtx_init(&ald_mtx, "ALDmtx", NULL, MTX_DEF|MTX_QUIET); 167 LIST_INIT(&ald_queues); 168 LIST_INIT(&ald_active); 169 } 170 171 static void 172 ald_daemon(void) 173 { 174 int needwakeup; 175 struct alq *alq; 176 177 ald_thread = FIRST_THREAD_IN_PROC(ald_proc); 178 179 EVENTHANDLER_REGISTER(shutdown_pre_sync, ald_shutdown, NULL, 180 SHUTDOWN_PRI_FIRST); 181 182 ALD_LOCK(); 183 184 for (;;) { 185 while ((alq = LIST_FIRST(&ald_active)) == NULL) 186 msleep(&ald_active, &ald_mtx, PWAIT, "aldslp", 0); 187 188 ALQ_LOCK(alq); 189 ald_deactivate(alq); 190 ALD_UNLOCK(); 191 needwakeup = alq_doio(alq); 192 ALQ_UNLOCK(alq); 193 if (needwakeup) 194 wakeup(alq); 195 ALD_LOCK(); 196 } 197 } 198 199 static void 200 ald_shutdown(void *arg, int howto) 201 { 202 struct alq *alq; 203 204 ALD_LOCK(); 205 ald_shutingdown = 1; 206 207 while ((alq = LIST_FIRST(&ald_queues)) != NULL) { 208 LIST_REMOVE(alq, aq_link); 209 ALD_UNLOCK(); 210 alq_shutdown(alq); 211 ALD_LOCK(); 212 } 213 ALD_UNLOCK(); 214 } 215 216 static void 217 alq_shutdown(struct alq *alq) 218 { 219 ALQ_LOCK(alq); 220 221 /* Stop any new writers. */ 222 alq->aq_flags |= AQ_SHUTDOWN; 223 224 /* Drain IO */ 225 while (alq->aq_flags & (AQ_FLUSHING|AQ_ACTIVE)) { 226 alq->aq_flags |= AQ_WANTED; 227 msleep_spin(alq, &alq->aq_mtx, "aldclose", 0); 228 } 229 ALQ_UNLOCK(alq); 230 231 vn_close(alq->aq_vp, FWRITE, alq->aq_cred, 232 curthread); 233 crfree(alq->aq_cred); 234 } 235 236 /* 237 * Flush all pending data to disk. This operation will block. 238 */ 239 static int 240 alq_doio(struct alq *alq) 241 { 242 struct thread *td; 243 struct mount *mp; 244 struct vnode *vp; 245 struct uio auio; 246 struct iovec aiov[2]; 247 struct ale *ale; 248 struct ale *alstart; 249 int totlen; 250 int iov; 251 int vfslocked; 252 253 vp = alq->aq_vp; 254 td = curthread; 255 totlen = 0; 256 iov = 0; 257 258 alstart = ale = alq->aq_entvalid; 259 alq->aq_entvalid = NULL; 260 261 bzero(&aiov, sizeof(aiov)); 262 bzero(&auio, sizeof(auio)); 263 264 do { 265 if (aiov[iov].iov_base == NULL) 266 aiov[iov].iov_base = ale->ae_data; 267 aiov[iov].iov_len += alq->aq_entlen; 268 totlen += alq->aq_entlen; 269 /* Check to see if we're wrapping the buffer */ 270 if (ale->ae_data + alq->aq_entlen != ale->ae_next->ae_data) 271 iov++; 272 ale->ae_flags &= ~AE_VALID; 273 ale = ale->ae_next; 274 } while (ale->ae_flags & AE_VALID); 275 276 alq->aq_flags |= AQ_FLUSHING; 277 ALQ_UNLOCK(alq); 278 279 if (iov == 2 || aiov[iov].iov_base == NULL) 280 iov--; 281 282 auio.uio_iov = &aiov[0]; 283 auio.uio_offset = 0; 284 auio.uio_segflg = UIO_SYSSPACE; 285 auio.uio_rw = UIO_WRITE; 286 auio.uio_iovcnt = iov + 1; 287 auio.uio_resid = totlen; 288 auio.uio_td = td; 289 290 /* 291 * Do all of the junk required to write now. 292 */ 293 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 294 vn_start_write(vp, &mp, V_WAIT); 295 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 296 /* 297 * XXX: VOP_WRITE error checks are ignored. 298 */ 299 #ifdef MAC 300 if (mac_vnode_check_write(alq->aq_cred, NOCRED, vp) == 0) 301 #endif 302 VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, alq->aq_cred); 303 VOP_UNLOCK(vp, 0); 304 vn_finished_write(mp); 305 VFS_UNLOCK_GIANT(vfslocked); 306 307 ALQ_LOCK(alq); 308 alq->aq_flags &= ~AQ_FLUSHING; 309 310 if (alq->aq_entfree == NULL) 311 alq->aq_entfree = alstart; 312 313 if (alq->aq_flags & AQ_WANTED) { 314 alq->aq_flags &= ~AQ_WANTED; 315 return (1); 316 } 317 318 return(0); 319 } 320 321 static struct kproc_desc ald_kp = { 322 "ALQ Daemon", 323 ald_daemon, 324 &ald_proc 325 }; 326 327 SYSINIT(aldthread, SI_SUB_KTHREAD_IDLE, SI_ORDER_ANY, kproc_start, &ald_kp); 328 SYSINIT(ald, SI_SUB_LOCK, SI_ORDER_ANY, ald_startup, NULL); 329 330 331 /* User visible queue functions */ 332 333 /* 334 * Create the queue data structure, allocate the buffer, and open the file. 335 */ 336 int 337 alq_open(struct alq **alqp, const char *file, struct ucred *cred, int cmode, 338 int size, int count) 339 { 340 struct thread *td; 341 struct nameidata nd; 342 struct ale *ale; 343 struct ale *alp; 344 struct alq *alq; 345 char *bufp; 346 int flags; 347 int error; 348 int i, vfslocked; 349 350 *alqp = NULL; 351 td = curthread; 352 353 NDINIT(&nd, LOOKUP, NOFOLLOW | MPSAFE, UIO_SYSSPACE, file, td); 354 flags = FWRITE | O_NOFOLLOW | O_CREAT; 355 356 error = vn_open_cred(&nd, &flags, cmode, cred, NULL); 357 if (error) 358 return (error); 359 360 vfslocked = NDHASGIANT(&nd); 361 NDFREE(&nd, NDF_ONLY_PNBUF); 362 /* We just unlock so we hold a reference */ 363 VOP_UNLOCK(nd.ni_vp, 0); 364 VFS_UNLOCK_GIANT(vfslocked); 365 366 alq = malloc(sizeof(*alq), M_ALD, M_WAITOK|M_ZERO); 367 alq->aq_entbuf = malloc(count * size, M_ALD, M_WAITOK|M_ZERO); 368 alq->aq_first = malloc(sizeof(*ale) * count, M_ALD, M_WAITOK|M_ZERO); 369 alq->aq_vp = nd.ni_vp; 370 alq->aq_cred = crhold(cred); 371 alq->aq_entmax = count; 372 alq->aq_entlen = size; 373 alq->aq_entfree = alq->aq_first; 374 375 mtx_init(&alq->aq_mtx, "ALD Queue", NULL, MTX_SPIN|MTX_QUIET); 376 377 bufp = alq->aq_entbuf; 378 ale = alq->aq_first; 379 alp = NULL; 380 381 /* Match up entries with buffers */ 382 for (i = 0; i < count; i++) { 383 if (alp) 384 alp->ae_next = ale; 385 ale->ae_data = bufp; 386 alp = ale; 387 ale++; 388 bufp += size; 389 } 390 391 alp->ae_next = alq->aq_first; 392 393 if ((error = ald_add(alq)) != 0) 394 return (error); 395 *alqp = alq; 396 397 return (0); 398 } 399 400 /* 401 * Copy a new entry into the queue. If the operation would block either 402 * wait or return an error depending on the value of waitok. 403 */ 404 int 405 alq_write(struct alq *alq, void *data, int waitok) 406 { 407 struct ale *ale; 408 409 if ((ale = alq_get(alq, waitok)) == NULL) 410 return (EWOULDBLOCK); 411 412 bcopy(data, ale->ae_data, alq->aq_entlen); 413 alq_post(alq, ale); 414 415 return (0); 416 } 417 418 struct ale * 419 alq_get(struct alq *alq, int waitok) 420 { 421 struct ale *ale; 422 struct ale *aln; 423 424 ale = NULL; 425 426 ALQ_LOCK(alq); 427 428 /* Loop until we get an entry or we're shutting down */ 429 while ((alq->aq_flags & AQ_SHUTDOWN) == 0 && 430 (ale = alq->aq_entfree) == NULL && 431 (waitok & ALQ_WAITOK)) { 432 alq->aq_flags |= AQ_WANTED; 433 msleep_spin(alq, &alq->aq_mtx, "alqget", 0); 434 } 435 436 if (ale != NULL) { 437 aln = ale->ae_next; 438 if ((aln->ae_flags & AE_VALID) == 0) 439 alq->aq_entfree = aln; 440 else 441 alq->aq_entfree = NULL; 442 } else 443 ALQ_UNLOCK(alq); 444 445 446 return (ale); 447 } 448 449 void 450 alq_post(struct alq *alq, struct ale *ale) 451 { 452 int activate; 453 454 ale->ae_flags |= AE_VALID; 455 456 if (alq->aq_entvalid == NULL) 457 alq->aq_entvalid = ale; 458 459 if ((alq->aq_flags & AQ_ACTIVE) == 0) { 460 alq->aq_flags |= AQ_ACTIVE; 461 activate = 1; 462 } else 463 activate = 0; 464 465 ALQ_UNLOCK(alq); 466 if (activate) { 467 ALD_LOCK(); 468 ald_activate(alq); 469 ALD_UNLOCK(); 470 } 471 } 472 473 void 474 alq_flush(struct alq *alq) 475 { 476 int needwakeup = 0; 477 478 ALD_LOCK(); 479 ALQ_LOCK(alq); 480 if (alq->aq_flags & AQ_ACTIVE) { 481 ald_deactivate(alq); 482 ALD_UNLOCK(); 483 needwakeup = alq_doio(alq); 484 } else 485 ALD_UNLOCK(); 486 ALQ_UNLOCK(alq); 487 488 if (needwakeup) 489 wakeup(alq); 490 } 491 492 /* 493 * Flush remaining data, close the file and free all resources. 494 */ 495 void 496 alq_close(struct alq *alq) 497 { 498 /* 499 * If we're already shuting down someone else will flush and close 500 * the vnode. 501 */ 502 if (ald_rem(alq) != 0) 503 return; 504 505 /* 506 * Drain all pending IO. 507 */ 508 alq_shutdown(alq); 509 510 mtx_destroy(&alq->aq_mtx); 511 free(alq->aq_first, M_ALD); 512 free(alq->aq_entbuf, M_ALD); 513 free(alq, M_ALD); 514 } 515