kern_proc.c revision 1.42
1 /* $NetBSD: kern_proc.c,v 1.42 2000/08/17 14:37:54 thorpej Exp $ */ 2 3 /*- 4 * Copyright (c) 1999 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 9 * NASA Ames Research Center. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the NetBSD 22 * Foundation, Inc. and its contributors. 23 * 4. Neither the name of The NetBSD Foundation nor the names of its 24 * contributors may be used to endorse or promote products derived 25 * from this software without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 37 * POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 /* 41 * Copyright (c) 1982, 1986, 1989, 1991, 1993 42 * The Regents of the University of California. All rights reserved. 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 * @(#)kern_proc.c 8.7 (Berkeley) 2/14/95 73 */ 74 75 #include <sys/param.h> 76 #include <sys/systm.h> 77 #include <sys/map.h> 78 #include <sys/kernel.h> 79 #include <sys/proc.h> 80 #include <sys/resourcevar.h> 81 #include <sys/buf.h> 82 #include <sys/acct.h> 83 #include <sys/wait.h> 84 #include <sys/file.h> 85 #include <ufs/ufs/quota.h> 86 #include <sys/uio.h> 87 #include <sys/malloc.h> 88 #include <sys/pool.h> 89 #include <sys/mbuf.h> 90 #include <sys/ioctl.h> 91 #include <sys/tty.h> 92 #include <sys/signalvar.h> 93 94 /* 95 * Structure associated with user cacheing. 96 */ 97 struct uidinfo { 98 LIST_ENTRY(uidinfo) ui_hash; 99 uid_t ui_uid; 100 long ui_proccnt; 101 }; 102 #define UIHASH(uid) (&uihashtbl[(uid) & uihash]) 103 LIST_HEAD(uihashhead, uidinfo) *uihashtbl; 104 u_long uihash; /* size of hash table - 1 */ 105 106 /* 107 * Other process lists 108 */ 109 struct pidhashhead *pidhashtbl; 110 u_long pidhash; 111 struct pgrphashhead *pgrphashtbl; 112 u_long pgrphash; 113 114 struct proclist allproc; 115 struct proclist zombproc; /* resources have been freed */ 116 117 /* 118 * Process list locking: 119 * 120 * We have two types of locks on the proclists: read locks and write 121 * locks. Read locks can be used in interrupt context, so while we 122 * hold the write lock, we must also block clock interrupts to 123 * lock out any scheduling changes that may happen in interrupt 124 * context. 125 * 126 * The proclist lock locks the following structures: 127 * 128 * allproc 129 * zombproc 130 * pidhashtbl 131 */ 132 struct lock proclist_lock; 133 134 /* 135 * Locking of this proclist is special; it's accessed in a 136 * critical section of process exit, and thus locking it can't 137 * modify interrupt state. We use a simple spin lock for this 138 * proclist. Processes on this proclist are also on zombproc; 139 * we use the p_hash member to linkup to deadproc. 140 */ 141 struct simplelock deadproc_slock; 142 struct proclist deadproc; /* dead, but not yet undead */ 143 144 struct pool proc_pool; 145 struct pool pcred_pool; 146 struct pool plimit_pool; 147 struct pool pgrp_pool; 148 struct pool rusage_pool; 149 150 /* 151 * The process list descriptors, used during pid allocation and 152 * by sysctl. No locking on this data structure is needed since 153 * it is completely static. 154 */ 155 const struct proclist_desc proclists[] = { 156 { &allproc }, 157 { &zombproc }, 158 { NULL }, 159 }; 160 161 static void orphanpg __P((struct pgrp *)); 162 #ifdef DEBUG 163 void pgrpdump __P((void)); 164 #endif 165 166 /* 167 * Initialize global process hashing structures. 168 */ 169 void 170 procinit() 171 { 172 const struct proclist_desc *pd; 173 174 for (pd = proclists; pd->pd_list != NULL; pd++) 175 LIST_INIT(pd->pd_list); 176 177 spinlockinit(&proclist_lock, "proclk", 0); 178 179 LIST_INIT(&deadproc); 180 simple_lock_init(&deadproc_slock); 181 182 pidhashtbl = hashinit(maxproc / 4, M_PROC, M_WAITOK, &pidhash); 183 pgrphashtbl = hashinit(maxproc / 4, M_PROC, M_WAITOK, &pgrphash); 184 uihashtbl = hashinit(maxproc / 16, M_PROC, M_WAITOK, &uihash); 185 186 pool_init(&proc_pool, sizeof(struct proc), 0, 0, 0, "procpl", 187 0, pool_page_alloc_nointr, pool_page_free_nointr, M_PROC); 188 pool_init(&pgrp_pool, sizeof(struct pgrp), 0, 0, 0, "pgrppl", 189 0, pool_page_alloc_nointr, pool_page_free_nointr, M_PGRP); 190 pool_init(&pcred_pool, sizeof(struct pcred), 0, 0, 0, "pcredpl", 191 0, pool_page_alloc_nointr, pool_page_free_nointr, M_SUBPROC); 192 pool_init(&plimit_pool, sizeof(struct plimit), 0, 0, 0, "plimitpl", 193 0, pool_page_alloc_nointr, pool_page_free_nointr, M_SUBPROC); 194 pool_init(&rusage_pool, sizeof(struct rusage), 0, 0, 0, "rusgepl", 195 0, pool_page_alloc_nointr, pool_page_free_nointr, M_ZOMBIE); 196 } 197 198 /* 199 * Acquire a read lock on the proclist. 200 */ 201 void 202 proclist_lock_read() 203 { 204 int error; 205 206 error = spinlockmgr(&proclist_lock, LK_SHARED, NULL); 207 #ifdef DIAGNOSTIC 208 if (__predict_false(error != 0)) 209 panic("proclist_lock_read: failed to acquire lock"); 210 #endif 211 } 212 213 /* 214 * Release a read lock on the proclist. 215 */ 216 void 217 proclist_unlock_read() 218 { 219 220 (void) spinlockmgr(&proclist_lock, LK_RELEASE, NULL); 221 } 222 223 /* 224 * Acquire a write lock on the proclist. 225 */ 226 int 227 proclist_lock_write() 228 { 229 int s, error; 230 231 s = splclock(); 232 error = spinlockmgr(&proclist_lock, LK_EXCLUSIVE, NULL); 233 #ifdef DIAGNOSTIC 234 if (__predict_false(error != 0)) 235 panic("proclist_lock: failed to acquire lock"); 236 #endif 237 return (s); 238 } 239 240 /* 241 * Release a write lock on the proclist. 242 */ 243 void 244 proclist_unlock_write(s) 245 int s; 246 { 247 248 (void) spinlockmgr(&proclist_lock, LK_RELEASE, NULL); 249 splx(s); 250 } 251 252 /* 253 * Change the count associated with number of processes 254 * a given user is using. 255 */ 256 int 257 chgproccnt(uid, diff) 258 uid_t uid; 259 int diff; 260 { 261 struct uidinfo *uip; 262 struct uihashhead *uipp; 263 264 uipp = UIHASH(uid); 265 for (uip = uipp->lh_first; uip != 0; uip = uip->ui_hash.le_next) 266 if (uip->ui_uid == uid) 267 break; 268 if (uip) { 269 uip->ui_proccnt += diff; 270 if (uip->ui_proccnt > 0) 271 return (uip->ui_proccnt); 272 if (uip->ui_proccnt < 0) 273 panic("chgproccnt: procs < 0"); 274 LIST_REMOVE(uip, ui_hash); 275 FREE(uip, M_PROC); 276 return (0); 277 } 278 if (diff <= 0) { 279 if (diff == 0) 280 return(0); 281 panic("chgproccnt: lost user"); 282 } 283 MALLOC(uip, struct uidinfo *, sizeof(*uip), M_PROC, M_WAITOK); 284 LIST_INSERT_HEAD(uipp, uip, ui_hash); 285 uip->ui_uid = uid; 286 uip->ui_proccnt = diff; 287 return (diff); 288 } 289 290 /* 291 * Is p an inferior of q? 292 */ 293 int 294 inferior(p, q) 295 struct proc *p; 296 struct proc *q; 297 { 298 299 for (; p != q; p = p->p_pptr) 300 if (p->p_pid == 0) 301 return (0); 302 return (1); 303 } 304 305 /* 306 * Locate a process by number 307 */ 308 struct proc * 309 pfind(pid) 310 pid_t pid; 311 { 312 struct proc *p; 313 314 proclist_lock_read(); 315 for (p = PIDHASH(pid)->lh_first; p != 0; p = p->p_hash.le_next) 316 if (p->p_pid == pid) 317 goto out; 318 out: 319 proclist_unlock_read(); 320 return (p); 321 } 322 323 /* 324 * Locate a process group by number 325 */ 326 struct pgrp * 327 pgfind(pgid) 328 pid_t pgid; 329 { 330 struct pgrp *pgrp; 331 332 for (pgrp = PGRPHASH(pgid)->lh_first; pgrp != 0; pgrp = pgrp->pg_hash.le_next) 333 if (pgrp->pg_id == pgid) 334 return (pgrp); 335 return (NULL); 336 } 337 338 /* 339 * Move p to a new or existing process group (and session) 340 */ 341 int 342 enterpgrp(p, pgid, mksess) 343 struct proc *p; 344 pid_t pgid; 345 int mksess; 346 { 347 struct pgrp *pgrp = pgfind(pgid); 348 349 #ifdef DIAGNOSTIC 350 if (__predict_false(pgrp != NULL && mksess)) /* firewalls */ 351 panic("enterpgrp: setsid into non-empty pgrp"); 352 if (__predict_false(SESS_LEADER(p))) 353 panic("enterpgrp: session leader attempted setpgrp"); 354 #endif 355 if (pgrp == NULL) { 356 pid_t savepid = p->p_pid; 357 struct proc *np; 358 /* 359 * new process group 360 */ 361 #ifdef DIAGNOSTIC 362 if (__predict_false(p->p_pid != pgid)) 363 panic("enterpgrp: new pgrp and pid != pgid"); 364 #endif 365 pgrp = pool_get(&pgrp_pool, PR_WAITOK); 366 if ((np = pfind(savepid)) == NULL || np != p) 367 return (ESRCH); 368 if (mksess) { 369 struct session *sess; 370 371 /* 372 * new session 373 */ 374 MALLOC(sess, struct session *, sizeof(struct session), 375 M_SESSION, M_WAITOK); 376 sess->s_sid = p->p_pid; 377 sess->s_leader = p; 378 sess->s_count = 1; 379 sess->s_ttyvp = NULL; 380 sess->s_ttyp = NULL; 381 memcpy(sess->s_login, p->p_session->s_login, 382 sizeof(sess->s_login)); 383 p->p_flag &= ~P_CONTROLT; 384 pgrp->pg_session = sess; 385 #ifdef DIAGNOSTIC 386 if (__predict_false(p != curproc)) 387 panic("enterpgrp: mksession and p != curproc"); 388 #endif 389 } else { 390 pgrp->pg_session = p->p_session; 391 pgrp->pg_session->s_count++; 392 } 393 pgrp->pg_id = pgid; 394 LIST_INIT(&pgrp->pg_members); 395 LIST_INSERT_HEAD(PGRPHASH(pgid), pgrp, pg_hash); 396 pgrp->pg_jobc = 0; 397 } else if (pgrp == p->p_pgrp) 398 return (0); 399 400 /* 401 * Adjust eligibility of affected pgrps to participate in job control. 402 * Increment eligibility counts before decrementing, otherwise we 403 * could reach 0 spuriously during the first call. 404 */ 405 fixjobc(p, pgrp, 1); 406 fixjobc(p, p->p_pgrp, 0); 407 408 LIST_REMOVE(p, p_pglist); 409 if (p->p_pgrp->pg_members.lh_first == 0) 410 pgdelete(p->p_pgrp); 411 p->p_pgrp = pgrp; 412 LIST_INSERT_HEAD(&pgrp->pg_members, p, p_pglist); 413 return (0); 414 } 415 416 /* 417 * remove process from process group 418 */ 419 int 420 leavepgrp(p) 421 struct proc *p; 422 { 423 424 LIST_REMOVE(p, p_pglist); 425 if (p->p_pgrp->pg_members.lh_first == 0) 426 pgdelete(p->p_pgrp); 427 p->p_pgrp = 0; 428 return (0); 429 } 430 431 /* 432 * delete a process group 433 */ 434 void 435 pgdelete(pgrp) 436 struct pgrp *pgrp; 437 { 438 439 if (pgrp->pg_session->s_ttyp != NULL && 440 pgrp->pg_session->s_ttyp->t_pgrp == pgrp) 441 pgrp->pg_session->s_ttyp->t_pgrp = NULL; 442 LIST_REMOVE(pgrp, pg_hash); 443 if (--pgrp->pg_session->s_count == 0) 444 FREE(pgrp->pg_session, M_SESSION); 445 pool_put(&pgrp_pool, pgrp); 446 } 447 448 /* 449 * Adjust pgrp jobc counters when specified process changes process group. 450 * We count the number of processes in each process group that "qualify" 451 * the group for terminal job control (those with a parent in a different 452 * process group of the same session). If that count reaches zero, the 453 * process group becomes orphaned. Check both the specified process' 454 * process group and that of its children. 455 * entering == 0 => p is leaving specified group. 456 * entering == 1 => p is entering specified group. 457 */ 458 void 459 fixjobc(p, pgrp, entering) 460 struct proc *p; 461 struct pgrp *pgrp; 462 int entering; 463 { 464 struct pgrp *hispgrp; 465 struct session *mysession = pgrp->pg_session; 466 467 /* 468 * Check p's parent to see whether p qualifies its own process 469 * group; if so, adjust count for p's process group. 470 */ 471 if ((hispgrp = p->p_pptr->p_pgrp) != pgrp && 472 hispgrp->pg_session == mysession) { 473 if (entering) 474 pgrp->pg_jobc++; 475 else if (--pgrp->pg_jobc == 0) 476 orphanpg(pgrp); 477 } 478 479 /* 480 * Check this process' children to see whether they qualify 481 * their process groups; if so, adjust counts for children's 482 * process groups. 483 */ 484 for (p = p->p_children.lh_first; p != 0; p = p->p_sibling.le_next) { 485 if ((hispgrp = p->p_pgrp) != pgrp && 486 hispgrp->pg_session == mysession && 487 P_ZOMBIE(p) == 0) { 488 if (entering) 489 hispgrp->pg_jobc++; 490 else if (--hispgrp->pg_jobc == 0) 491 orphanpg(hispgrp); 492 } 493 } 494 } 495 496 /* 497 * A process group has become orphaned; 498 * if there are any stopped processes in the group, 499 * hang-up all process in that group. 500 */ 501 static void 502 orphanpg(pg) 503 struct pgrp *pg; 504 { 505 struct proc *p; 506 507 for (p = pg->pg_members.lh_first; p != 0; p = p->p_pglist.le_next) { 508 if (p->p_stat == SSTOP) { 509 for (p = pg->pg_members.lh_first; p != 0; 510 p = p->p_pglist.le_next) { 511 psignal(p, SIGHUP); 512 psignal(p, SIGCONT); 513 } 514 return; 515 } 516 } 517 } 518 519 /* mark process as suid/sgid, reset some values do defaults */ 520 void 521 p_sugid(p) 522 struct proc *p; 523 { 524 struct plimit *newlim; 525 526 p->p_flag |= P_SUGID; 527 /* reset what needs to be reset in plimit */ 528 if (p->p_limit->pl_corename != defcorename) { 529 if (p->p_limit->p_refcnt > 1 && 530 (p->p_limit->p_lflags & PL_SHAREMOD) == 0) { 531 newlim = limcopy(p->p_limit); 532 limfree(p->p_limit); 533 p->p_limit = newlim; 534 } else { 535 free(p->p_limit->pl_corename, M_TEMP); 536 } 537 p->p_limit->pl_corename = defcorename; 538 } 539 } 540 541 542 #ifdef DEBUG 543 void 544 pgrpdump() 545 { 546 struct pgrp *pgrp; 547 struct proc *p; 548 int i; 549 550 for (i = 0; i <= pgrphash; i++) { 551 if ((pgrp = pgrphashtbl[i].lh_first) != NULL) { 552 printf("\tindx %d\n", i); 553 for (; pgrp != 0; pgrp = pgrp->pg_hash.le_next) { 554 printf("\tpgrp %p, pgid %d, sess %p, sesscnt %d, mem %p\n", 555 pgrp, pgrp->pg_id, pgrp->pg_session, 556 pgrp->pg_session->s_count, 557 pgrp->pg_members.lh_first); 558 for (p = pgrp->pg_members.lh_first; p != 0; 559 p = p->p_pglist.le_next) { 560 printf("\t\tpid %d addr %p pgrp %p\n", 561 p->p_pid, p, p->p_pgrp); 562 } 563 } 564 } 565 } 566 } 567 #endif /* DEBUG */ 568
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