| 1 | /* $FreeBSD: src/sys/kern/sysv_sem.c,v 1.69 2004/03/17 09:37:13 cperciva Exp $ */ |
| 2 | /* $DragonFly: src/sys/kern/sysv_sem.c,v 1.19 2008/01/06 16:55:51 swildner Exp $ */ |
| 3 | |
| 4 | /* |
| 5 | * Implementation of SVID semaphores |
| 6 | * |
| 7 | * Author: Daniel Boulet |
| 8 | * |
| 9 | * This software is provided ``AS IS'' without any warranties of any kind. |
| 10 | */ |
| 11 | |
| 12 | #include "opt_sysvipc.h" |
| 13 | |
| 14 | #include <sys/param.h> |
| 15 | #include <sys/systm.h> |
| 16 | #include <sys/sysproto.h> |
| 17 | #include <sys/kernel.h> |
| 18 | #include <sys/proc.h> |
| 19 | #include <sys/sem.h> |
| 20 | #include <sys/sysent.h> |
| 21 | #include <sys/sysctl.h> |
| 22 | #include <sys/malloc.h> |
| 23 | #include <sys/jail.h> |
| 24 | |
| 25 | static MALLOC_DEFINE(M_SEM, "sem", "SVID compatible semaphores"); |
| 26 | |
| 27 | static void seminit (void *); |
| 28 | |
| 29 | static struct sem_undo *semu_alloc (struct proc *p); |
| 30 | static int semundo_adjust (struct proc *p, struct sem_undo **supptr, |
| 31 | int semid, int semnum, int adjval); |
| 32 | static void semundo_clear (int semid, int semnum); |
| 33 | |
| 34 | /* XXX casting to (sy_call_t *) is bogus, as usual. */ |
| 35 | static sy_call_t *semcalls[] = { |
| 36 | (sy_call_t *)sys___semctl, (sy_call_t *)sys_semget, |
| 37 | (sy_call_t *)sys_semop |
| 38 | }; |
| 39 | |
| 40 | static int semtot = 0; |
| 41 | static struct semid_ds *sema; /* semaphore id pool */ |
| 42 | static struct sem *sem; /* semaphore pool */ |
| 43 | static struct sem_undo *semu_list; /* list of active undo structures */ |
| 44 | static int *semu; /* undo structure pool */ |
| 45 | |
| 46 | struct sem { |
| 47 | u_short semval; /* semaphore value */ |
| 48 | pid_t sempid; /* pid of last operation */ |
| 49 | u_short semncnt; /* # awaiting semval > cval */ |
| 50 | u_short semzcnt; /* # awaiting semval = 0 */ |
| 51 | }; |
| 52 | |
| 53 | /* |
| 54 | * Undo structure (one per process) |
| 55 | */ |
| 56 | struct sem_undo { |
| 57 | struct sem_undo *un_next; /* ptr to next active undo structure */ |
| 58 | struct proc *un_proc; /* owner of this structure */ |
| 59 | short un_cnt; /* # of active entries */ |
| 60 | struct undo { |
| 61 | short un_adjval; /* adjust on exit values */ |
| 62 | short un_num; /* semaphore # */ |
| 63 | int un_id; /* semid */ |
| 64 | } un_ent[1]; /* undo entries */ |
| 65 | }; |
| 66 | |
| 67 | /* |
| 68 | * Configuration parameters |
| 69 | */ |
| 70 | #ifndef SEMMNI |
| 71 | #define SEMMNI 10 /* # of semaphore identifiers */ |
| 72 | #endif |
| 73 | #ifndef SEMMNS |
| 74 | #define SEMMNS 60 /* # of semaphores in system */ |
| 75 | #endif |
| 76 | #ifndef SEMUME |
| 77 | #define SEMUME 10 /* max # of undo entries per process */ |
| 78 | #endif |
| 79 | #ifndef SEMMNU |
| 80 | #define SEMMNU 30 /* # of undo structures in system */ |
| 81 | #endif |
| 82 | |
| 83 | /* shouldn't need tuning */ |
| 84 | #ifndef SEMMAP |
| 85 | #define SEMMAP 30 /* # of entries in semaphore map */ |
| 86 | #endif |
| 87 | #ifndef SEMMSL |
| 88 | #define SEMMSL SEMMNS /* max # of semaphores per id */ |
| 89 | #endif |
| 90 | #ifndef SEMOPM |
| 91 | #define SEMOPM 100 /* max # of operations per semop call */ |
| 92 | #endif |
| 93 | |
| 94 | #define SEMVMX 32767 /* semaphore maximum value */ |
| 95 | #define SEMAEM 16384 /* adjust on exit max value */ |
| 96 | |
| 97 | /* |
| 98 | * Due to the way semaphore memory is allocated, we have to ensure that |
| 99 | * SEMUSZ is properly aligned. |
| 100 | */ |
| 101 | |
| 102 | #define SEM_ALIGN(bytes) (((bytes) + (sizeof(long) - 1)) & ~(sizeof(long) - 1)) |
| 103 | |
| 104 | /* actual size of an undo structure */ |
| 105 | #define SEMUSZ SEM_ALIGN(offsetof(struct sem_undo, un_ent[SEMUME])) |
| 106 | |
| 107 | /* |
| 108 | * Macro to find a particular sem_undo vector |
| 109 | */ |
| 110 | #define SEMU(ix) ((struct sem_undo *)(((intptr_t)semu)+ix * seminfo.semusz)) |
| 111 | |
| 112 | /* |
| 113 | * semaphore info struct |
| 114 | */ |
| 115 | struct seminfo seminfo = { |
| 116 | SEMMAP, /* # of entries in semaphore map */ |
| 117 | SEMMNI, /* # of semaphore identifiers */ |
| 118 | SEMMNS, /* # of semaphores in system */ |
| 119 | SEMMNU, /* # of undo structures in system */ |
| 120 | SEMMSL, /* max # of semaphores per id */ |
| 121 | SEMOPM, /* max # of operations per semop call */ |
| 122 | SEMUME, /* max # of undo entries per process */ |
| 123 | SEMUSZ, /* size in bytes of undo structure */ |
| 124 | SEMVMX, /* semaphore maximum value */ |
| 125 | SEMAEM /* adjust on exit max value */ |
| 126 | }; |
| 127 | |
| 128 | TUNABLE_INT("kern.ipc.semmap", &seminfo.semmap); |
| 129 | TUNABLE_INT("kern.ipc.semmni", &seminfo.semmni); |
| 130 | TUNABLE_INT("kern.ipc.semmns", &seminfo.semmns); |
| 131 | TUNABLE_INT("kern.ipc.semmnu", &seminfo.semmnu); |
| 132 | TUNABLE_INT("kern.ipc.semmsl", &seminfo.semmsl); |
| 133 | TUNABLE_INT("kern.ipc.semopm", &seminfo.semopm); |
| 134 | TUNABLE_INT("kern.ipc.semume", &seminfo.semume); |
| 135 | TUNABLE_INT("kern.ipc.semusz", &seminfo.semusz); |
| 136 | TUNABLE_INT("kern.ipc.semvmx", &seminfo.semvmx); |
| 137 | TUNABLE_INT("kern.ipc.semaem", &seminfo.semaem); |
| 138 | |
| 139 | SYSCTL_INT(_kern_ipc, OID_AUTO, semmap, CTLFLAG_RW, &seminfo.semmap, 0, ""); |
| 140 | SYSCTL_INT(_kern_ipc, OID_AUTO, semmni, CTLFLAG_RD, &seminfo.semmni, 0, ""); |
| 141 | SYSCTL_INT(_kern_ipc, OID_AUTO, semmns, CTLFLAG_RD, &seminfo.semmns, 0, ""); |
| 142 | SYSCTL_INT(_kern_ipc, OID_AUTO, semmnu, CTLFLAG_RD, &seminfo.semmnu, 0, ""); |
| 143 | SYSCTL_INT(_kern_ipc, OID_AUTO, semmsl, CTLFLAG_RW, &seminfo.semmsl, 0, ""); |
| 144 | SYSCTL_INT(_kern_ipc, OID_AUTO, semopm, CTLFLAG_RD, &seminfo.semopm, 0, ""); |
| 145 | SYSCTL_INT(_kern_ipc, OID_AUTO, semume, CTLFLAG_RD, &seminfo.semume, 0, ""); |
| 146 | SYSCTL_INT(_kern_ipc, OID_AUTO, semusz, CTLFLAG_RD, &seminfo.semusz, 0, ""); |
| 147 | SYSCTL_INT(_kern_ipc, OID_AUTO, semvmx, CTLFLAG_RW, &seminfo.semvmx, 0, ""); |
| 148 | SYSCTL_INT(_kern_ipc, OID_AUTO, semaem, CTLFLAG_RW, &seminfo.semaem, 0, ""); |
| 149 | |
| 150 | #if 0 |
| 151 | RO seminfo.semmap /* SEMMAP unused */ |
| 152 | RO seminfo.semmni |
| 153 | RO seminfo.semmns |
| 154 | RO seminfo.semmnu /* undo entries per system */ |
| 155 | RW seminfo.semmsl |
| 156 | RO seminfo.semopm /* SEMOPM unused */ |
| 157 | RO seminfo.semume |
| 158 | RO seminfo.semusz /* param - derived from SEMUME for per-proc sizeof */ |
| 159 | RO seminfo.semvmx /* SEMVMX unused - user param */ |
| 160 | RO seminfo.semaem /* SEMAEM unused - user param */ |
| 161 | #endif |
| 162 | |
| 163 | static void |
| 164 | seminit(void *dummy) |
| 165 | { |
| 166 | int i; |
| 167 | |
| 168 | sem = kmalloc(sizeof(struct sem) * seminfo.semmns, M_SEM, M_WAITOK); |
| 169 | sema = kmalloc(sizeof(struct semid_ds) * seminfo.semmni, M_SEM, M_WAITOK); |
| 170 | semu = kmalloc(seminfo.semmnu * seminfo.semusz, M_SEM, M_WAITOK); |
| 171 | |
| 172 | for (i = 0; i < seminfo.semmni; i++) { |
| 173 | sema[i].sem_base = 0; |
| 174 | sema[i].sem_perm.mode = 0; |
| 175 | } |
| 176 | for (i = 0; i < seminfo.semmnu; i++) { |
| 177 | struct sem_undo *suptr = SEMU(i); |
| 178 | suptr->un_proc = NULL; |
| 179 | } |
| 180 | semu_list = NULL; |
| 181 | } |
| 182 | SYSINIT(sysv_sem, SI_SUB_SYSV_SEM, SI_ORDER_FIRST, seminit, NULL) |
| 183 | |
| 184 | /* |
| 185 | * Entry point for all SEM calls |
| 186 | * |
| 187 | * semsys_args(int which, a2, a3, ...) (VARARGS) |
| 188 | * |
| 189 | * MPALMOSTSAFE |
| 190 | */ |
| 191 | int |
| 192 | sys_semsys(struct semsys_args *uap) |
| 193 | { |
| 194 | struct thread *td = curthread; |
| 195 | unsigned int which = (unsigned int)uap->which; |
| 196 | int error; |
| 197 | |
| 198 | if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) |
| 199 | return (ENOSYS); |
| 200 | |
| 201 | if (which >= sizeof(semcalls)/sizeof(semcalls[0])) |
| 202 | return (EINVAL); |
| 203 | bcopy(&uap->a2, &uap->which, |
| 204 | sizeof(struct semsys_args) - offsetof(struct semsys_args, a2)); |
| 205 | get_mplock(); |
| 206 | error = (*semcalls[which])(uap); |
| 207 | rel_mplock(); |
| 208 | return (error); |
| 209 | } |
| 210 | |
| 211 | /* |
| 212 | * Allocate a new sem_undo structure for a process |
| 213 | * (returns ptr to structure or NULL if no more room) |
| 214 | */ |
| 215 | |
| 216 | static struct sem_undo * |
| 217 | semu_alloc(struct proc *p) |
| 218 | { |
| 219 | int i; |
| 220 | struct sem_undo *suptr; |
| 221 | struct sem_undo **supptr; |
| 222 | int attempt; |
| 223 | |
| 224 | /* |
| 225 | * Try twice to allocate something. |
| 226 | * (we'll purge any empty structures after the first pass so |
| 227 | * two passes are always enough) |
| 228 | */ |
| 229 | |
| 230 | for (attempt = 0; attempt < 2; attempt++) { |
| 231 | /* |
| 232 | * Look for a free structure. |
| 233 | * Fill it in and return it if we find one. |
| 234 | */ |
| 235 | |
| 236 | for (i = 0; i < seminfo.semmnu; i++) { |
| 237 | suptr = SEMU(i); |
| 238 | if (suptr->un_proc == NULL) { |
| 239 | suptr->un_next = semu_list; |
| 240 | semu_list = suptr; |
| 241 | suptr->un_cnt = 0; |
| 242 | suptr->un_proc = p; |
| 243 | return(suptr); |
| 244 | } |
| 245 | } |
| 246 | |
| 247 | /* |
| 248 | * We didn't find a free one, if this is the first attempt |
| 249 | * then try to free some structures. |
| 250 | */ |
| 251 | |
| 252 | if (attempt == 0) { |
| 253 | /* All the structures are in use - try to free some */ |
| 254 | int did_something = 0; |
| 255 | |
| 256 | supptr = &semu_list; |
| 257 | while ((suptr = *supptr) != NULL) { |
| 258 | if (suptr->un_cnt == 0) { |
| 259 | suptr->un_proc = NULL; |
| 260 | *supptr = suptr->un_next; |
| 261 | did_something = 1; |
| 262 | } else |
| 263 | supptr = &(suptr->un_next); |
| 264 | } |
| 265 | |
| 266 | /* If we didn't free anything then just give-up */ |
| 267 | if (!did_something) |
| 268 | return(NULL); |
| 269 | } else { |
| 270 | /* |
| 271 | * The second pass failed even though we freed |
| 272 | * something after the first pass! |
| 273 | * This is IMPOSSIBLE! |
| 274 | */ |
| 275 | panic("semu_alloc - second attempt failed"); |
| 276 | } |
| 277 | } |
| 278 | return (NULL); |
| 279 | } |
| 280 | |
| 281 | /* |
| 282 | * Adjust a particular entry for a particular proc |
| 283 | */ |
| 284 | |
| 285 | static int |
| 286 | semundo_adjust(struct proc *p, struct sem_undo **supptr, int semid, int semnum, |
| 287 | int adjval) |
| 288 | { |
| 289 | struct sem_undo *suptr; |
| 290 | struct undo *sunptr; |
| 291 | int i; |
| 292 | |
| 293 | /* Look for and remember the sem_undo if the caller doesn't provide |
| 294 | it */ |
| 295 | |
| 296 | suptr = *supptr; |
| 297 | if (suptr == NULL) { |
| 298 | for (suptr = semu_list; suptr != NULL; |
| 299 | suptr = suptr->un_next) { |
| 300 | if (suptr->un_proc == p) { |
| 301 | *supptr = suptr; |
| 302 | break; |
| 303 | } |
| 304 | } |
| 305 | if (suptr == NULL) { |
| 306 | if (adjval == 0) |
| 307 | return(0); |
| 308 | suptr = semu_alloc(p); |
| 309 | if (suptr == NULL) |
| 310 | return(ENOSPC); |
| 311 | *supptr = suptr; |
| 312 | } |
| 313 | } |
| 314 | |
| 315 | /* |
| 316 | * Look for the requested entry and adjust it (delete if adjval becomes |
| 317 | * 0). |
| 318 | */ |
| 319 | sunptr = &suptr->un_ent[0]; |
| 320 | for (i = 0; i < suptr->un_cnt; i++, sunptr++) { |
| 321 | if (sunptr->un_id != semid || sunptr->un_num != semnum) |
| 322 | continue; |
| 323 | if (adjval == 0) |
| 324 | sunptr->un_adjval = 0; |
| 325 | else |
| 326 | sunptr->un_adjval += adjval; |
| 327 | if (sunptr->un_adjval == 0) { |
| 328 | suptr->un_cnt--; |
| 329 | if (i < suptr->un_cnt) |
| 330 | suptr->un_ent[i] = |
| 331 | suptr->un_ent[suptr->un_cnt]; |
| 332 | } |
| 333 | return(0); |
| 334 | } |
| 335 | |
| 336 | /* Didn't find the right entry - create it */ |
| 337 | if (adjval == 0) |
| 338 | return(0); |
| 339 | if (suptr->un_cnt != seminfo.semume) { |
| 340 | sunptr = &suptr->un_ent[suptr->un_cnt]; |
| 341 | suptr->un_cnt++; |
| 342 | sunptr->un_adjval = adjval; |
| 343 | sunptr->un_id = semid; sunptr->un_num = semnum; |
| 344 | } else |
| 345 | return(EINVAL); |
| 346 | return(0); |
| 347 | } |
| 348 | |
| 349 | static void |
| 350 | semundo_clear(int semid, int semnum) |
| 351 | { |
| 352 | struct sem_undo *suptr; |
| 353 | |
| 354 | for (suptr = semu_list; suptr != NULL; suptr = suptr->un_next) { |
| 355 | struct undo *sunptr = &suptr->un_ent[0]; |
| 356 | int i = 0; |
| 357 | |
| 358 | while (i < suptr->un_cnt) { |
| 359 | if (sunptr->un_id == semid) { |
| 360 | if (semnum == -1 || sunptr->un_num == semnum) { |
| 361 | suptr->un_cnt--; |
| 362 | if (i < suptr->un_cnt) { |
| 363 | suptr->un_ent[i] = |
| 364 | suptr->un_ent[suptr->un_cnt]; |
| 365 | continue; |
| 366 | } |
| 367 | } |
| 368 | if (semnum != -1) |
| 369 | break; |
| 370 | } |
| 371 | i++, sunptr++; |
| 372 | } |
| 373 | } |
| 374 | } |
| 375 | |
| 376 | /* |
| 377 | * Note that the user-mode half of this passes a union, not a pointer |
| 378 | * |
| 379 | * MPALMOSTSAFE |
| 380 | */ |
| 381 | int |
| 382 | sys___semctl(struct __semctl_args *uap) |
| 383 | { |
| 384 | struct thread *td = curthread; |
| 385 | int semid = uap->semid; |
| 386 | int semnum = uap->semnum; |
| 387 | int cmd = uap->cmd; |
| 388 | union semun *arg = uap->arg; |
| 389 | union semun real_arg; |
| 390 | struct ucred *cred = td->td_ucred; |
| 391 | int i, rval, eval; |
| 392 | struct semid_ds sbuf; |
| 393 | struct semid_ds *semaptr; |
| 394 | |
| 395 | #ifdef SEM_DEBUG |
| 396 | kprintf("call to semctl(%d, %d, %d, 0x%x)\n", semid, semnum, cmd, arg); |
| 397 | #endif |
| 398 | |
| 399 | if (!jail_sysvipc_allowed && cred->cr_prison != NULL) |
| 400 | return (ENOSYS); |
| 401 | |
| 402 | semid = IPCID_TO_IX(semid); |
| 403 | if (semid < 0 || semid >= seminfo.semmni) |
| 404 | return(EINVAL); |
| 405 | |
| 406 | get_mplock(); |
| 407 | semaptr = &sema[semid]; |
| 408 | if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0 || |
| 409 | semaptr->sem_perm.seq != IPCID_TO_SEQ(uap->semid)) { |
| 410 | rel_mplock(); |
| 411 | return(EINVAL); |
| 412 | } |
| 413 | |
| 414 | eval = 0; |
| 415 | rval = 0; |
| 416 | |
| 417 | switch (cmd) { |
| 418 | case IPC_RMID: |
| 419 | if ((eval = ipcperm(td->td_proc, &semaptr->sem_perm, IPC_M)) != 0) |
| 420 | break; |
| 421 | semaptr->sem_perm.cuid = cred->cr_uid; |
| 422 | semaptr->sem_perm.uid = cred->cr_uid; |
| 423 | semtot -= semaptr->sem_nsems; |
| 424 | for (i = semaptr->sem_base - sem; i < semtot; i++) |
| 425 | sem[i] = sem[i + semaptr->sem_nsems]; |
| 426 | for (i = 0; i < seminfo.semmni; i++) { |
| 427 | if ((sema[i].sem_perm.mode & SEM_ALLOC) && |
| 428 | sema[i].sem_base > semaptr->sem_base) |
| 429 | sema[i].sem_base -= semaptr->sem_nsems; |
| 430 | } |
| 431 | semaptr->sem_perm.mode = 0; |
| 432 | semundo_clear(semid, -1); |
| 433 | wakeup((caddr_t)semaptr); |
| 434 | break; |
| 435 | |
| 436 | case IPC_SET: |
| 437 | eval = ipcperm(td->td_proc, &semaptr->sem_perm, IPC_M); |
| 438 | if (eval) |
| 439 | break; |
| 440 | if ((eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0) |
| 441 | break; |
| 442 | if ((eval = copyin(real_arg.buf, (caddr_t)&sbuf, |
| 443 | sizeof(sbuf))) != 0) { |
| 444 | break; |
| 445 | } |
| 446 | semaptr->sem_perm.uid = sbuf.sem_perm.uid; |
| 447 | semaptr->sem_perm.gid = sbuf.sem_perm.gid; |
| 448 | semaptr->sem_perm.mode = (semaptr->sem_perm.mode & ~0777) | |
| 449 | (sbuf.sem_perm.mode & 0777); |
| 450 | semaptr->sem_ctime = time_second; |
| 451 | break; |
| 452 | |
| 453 | case IPC_STAT: |
| 454 | if ((eval = ipcperm(td->td_proc, &semaptr->sem_perm, IPC_R))) |
| 455 | break; |
| 456 | if ((eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0) |
| 457 | break; |
| 458 | eval = copyout(semaptr, real_arg.buf, sizeof(struct semid_ds)); |
| 459 | break; |
| 460 | |
| 461 | case GETNCNT: |
| 462 | eval = ipcperm(td->td_proc, &semaptr->sem_perm, IPC_R); |
| 463 | if (eval) |
| 464 | break; |
| 465 | if (semnum < 0 || semnum >= semaptr->sem_nsems) { |
| 466 | eval = EINVAL; |
| 467 | break; |
| 468 | } |
| 469 | rval = semaptr->sem_base[semnum].semncnt; |
| 470 | break; |
| 471 | |
| 472 | case GETPID: |
| 473 | eval = ipcperm(td->td_proc, &semaptr->sem_perm, IPC_R); |
| 474 | if (eval) |
| 475 | break; |
| 476 | if (semnum < 0 || semnum >= semaptr->sem_nsems) { |
| 477 | eval = EINVAL; |
| 478 | break; |
| 479 | } |
| 480 | rval = semaptr->sem_base[semnum].sempid; |
| 481 | break; |
| 482 | |
| 483 | case GETVAL: |
| 484 | eval = ipcperm(td->td_proc, &semaptr->sem_perm, IPC_R); |
| 485 | if (eval) |
| 486 | break; |
| 487 | if (semnum < 0 || semnum >= semaptr->sem_nsems) { |
| 488 | eval = EINVAL; |
| 489 | break; |
| 490 | } |
| 491 | rval = semaptr->sem_base[semnum].semval; |
| 492 | break; |
| 493 | |
| 494 | case GETALL: |
| 495 | eval = ipcperm(td->td_proc, &semaptr->sem_perm, IPC_R); |
| 496 | if (eval) |
| 497 | break; |
| 498 | if ((eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0) |
| 499 | break; |
| 500 | for (i = 0; i < semaptr->sem_nsems; i++) { |
| 501 | eval = copyout(&semaptr->sem_base[i].semval, |
| 502 | &real_arg.array[i], |
| 503 | sizeof(real_arg.array[0])); |
| 504 | if (eval) |
| 505 | break; |
| 506 | } |
| 507 | break; |
| 508 | |
| 509 | case GETZCNT: |
| 510 | eval = ipcperm(td->td_proc, &semaptr->sem_perm, IPC_R); |
| 511 | if (eval) |
| 512 | break; |
| 513 | if (semnum < 0 || semnum >= semaptr->sem_nsems) { |
| 514 | eval = EINVAL; |
| 515 | break; |
| 516 | } |
| 517 | rval = semaptr->sem_base[semnum].semzcnt; |
| 518 | break; |
| 519 | |
| 520 | case SETVAL: |
| 521 | eval = ipcperm(td->td_proc, &semaptr->sem_perm, IPC_W); |
| 522 | if (eval) |
| 523 | break; |
| 524 | if (semnum < 0 || semnum >= semaptr->sem_nsems) { |
| 525 | eval = EINVAL; |
| 526 | break; |
| 527 | } |
| 528 | if ((eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0) |
| 529 | break; |
| 530 | semaptr->sem_base[semnum].semval = real_arg.val; |
| 531 | semundo_clear(semid, semnum); |
| 532 | wakeup((caddr_t)semaptr); |
| 533 | break; |
| 534 | |
| 535 | case SETALL: |
| 536 | eval = ipcperm(td->td_proc, &semaptr->sem_perm, IPC_W); |
| 537 | if (eval) |
| 538 | break; |
| 539 | if ((eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0) |
| 540 | break; |
| 541 | for (i = 0; i < semaptr->sem_nsems; i++) { |
| 542 | eval = copyin(&real_arg.array[i], |
| 543 | (caddr_t)&semaptr->sem_base[i].semval, |
| 544 | sizeof(real_arg.array[0])); |
| 545 | if (eval != 0) |
| 546 | break; |
| 547 | } |
| 548 | semundo_clear(semid, -1); |
| 549 | wakeup((caddr_t)semaptr); |
| 550 | break; |
| 551 | |
| 552 | default: |
| 553 | eval = EINVAL; |
| 554 | break; |
| 555 | } |
| 556 | rel_mplock(); |
| 557 | |
| 558 | if (eval == 0) |
| 559 | uap->sysmsg_result = rval; |
| 560 | return(eval); |
| 561 | } |
| 562 | |
| 563 | /* |
| 564 | * MPALMOSTSAFE |
| 565 | */ |
| 566 | int |
| 567 | sys_semget(struct semget_args *uap) |
| 568 | { |
| 569 | struct thread *td = curthread; |
| 570 | int semid, eval; |
| 571 | int key = uap->key; |
| 572 | int nsems = uap->nsems; |
| 573 | int semflg = uap->semflg; |
| 574 | struct ucred *cred = td->td_ucred; |
| 575 | |
| 576 | #ifdef SEM_DEBUG |
| 577 | kprintf("semget(0x%x, %d, 0%o)\n", key, nsems, semflg); |
| 578 | #endif |
| 579 | |
| 580 | if (!jail_sysvipc_allowed && cred->cr_prison != NULL) |
| 581 | return (ENOSYS); |
| 582 | |
| 583 | get_mplock(); |
| 584 | eval = 0; |
| 585 | |
| 586 | if (key != IPC_PRIVATE) { |
| 587 | for (semid = 0; semid < seminfo.semmni; semid++) { |
| 588 | if ((sema[semid].sem_perm.mode & SEM_ALLOC) && |
| 589 | sema[semid].sem_perm.key == key) |
| 590 | break; |
| 591 | } |
| 592 | if (semid < seminfo.semmni) { |
| 593 | #ifdef SEM_DEBUG |
| 594 | kprintf("found public key\n"); |
| 595 | #endif |
| 596 | if ((eval = ipcperm(td->td_proc, |
| 597 | &sema[semid].sem_perm, |
| 598 | semflg & 0700))) { |
| 599 | goto done; |
| 600 | } |
| 601 | if (nsems > 0 && sema[semid].sem_nsems < nsems) { |
| 602 | #ifdef SEM_DEBUG |
| 603 | kprintf("too small\n"); |
| 604 | #endif |
| 605 | eval = EINVAL; |
| 606 | goto done; |
| 607 | } |
| 608 | if ((semflg & IPC_CREAT) && (semflg & IPC_EXCL)) { |
| 609 | #ifdef SEM_DEBUG |
| 610 | kprintf("not exclusive\n"); |
| 611 | #endif |
| 612 | eval = EEXIST; |
| 613 | goto done; |
| 614 | } |
| 615 | goto done; |
| 616 | } |
| 617 | } |
| 618 | |
| 619 | #ifdef SEM_DEBUG |
| 620 | kprintf("need to allocate the semid_ds\n"); |
| 621 | #endif |
| 622 | if (key == IPC_PRIVATE || (semflg & IPC_CREAT)) { |
| 623 | if (nsems <= 0 || nsems > seminfo.semmsl) { |
| 624 | #ifdef SEM_DEBUG |
| 625 | kprintf("nsems out of range (0<%d<=%d)\n", nsems, |
| 626 | seminfo.semmsl); |
| 627 | #endif |
| 628 | eval = EINVAL; |
| 629 | goto done; |
| 630 | } |
| 631 | if (nsems > seminfo.semmns - semtot) { |
| 632 | #ifdef SEM_DEBUG |
| 633 | kprintf("not enough semaphores left (need %d, got %d)\n", |
| 634 | nsems, seminfo.semmns - semtot); |
| 635 | #endif |
| 636 | eval = ENOSPC; |
| 637 | goto done; |
| 638 | } |
| 639 | for (semid = 0; semid < seminfo.semmni; semid++) { |
| 640 | if ((sema[semid].sem_perm.mode & SEM_ALLOC) == 0) |
| 641 | break; |
| 642 | } |
| 643 | if (semid == seminfo.semmni) { |
| 644 | #ifdef SEM_DEBUG |
| 645 | kprintf("no more semid_ds's available\n"); |
| 646 | #endif |
| 647 | eval = ENOSPC; |
| 648 | goto done; |
| 649 | } |
| 650 | #ifdef SEM_DEBUG |
| 651 | kprintf("semid %d is available\n", semid); |
| 652 | #endif |
| 653 | sema[semid].sem_perm.key = key; |
| 654 | sema[semid].sem_perm.cuid = cred->cr_uid; |
| 655 | sema[semid].sem_perm.uid = cred->cr_uid; |
| 656 | sema[semid].sem_perm.cgid = cred->cr_gid; |
| 657 | sema[semid].sem_perm.gid = cred->cr_gid; |
| 658 | sema[semid].sem_perm.mode = (semflg & 0777) | SEM_ALLOC; |
| 659 | sema[semid].sem_perm.seq = |
| 660 | (sema[semid].sem_perm.seq + 1) & 0x7fff; |
| 661 | sema[semid].sem_nsems = nsems; |
| 662 | sema[semid].sem_otime = 0; |
| 663 | sema[semid].sem_ctime = time_second; |
| 664 | sema[semid].sem_base = &sem[semtot]; |
| 665 | semtot += nsems; |
| 666 | bzero(sema[semid].sem_base, |
| 667 | sizeof(sema[semid].sem_base[0])*nsems); |
| 668 | #ifdef SEM_DEBUG |
| 669 | kprintf("sembase = 0x%x, next = 0x%x\n", sema[semid].sem_base, |
| 670 | &sem[semtot]); |
| 671 | #endif |
| 672 | } else { |
| 673 | #ifdef SEM_DEBUG |
| 674 | kprintf("didn't find it and wasn't asked to create it\n"); |
| 675 | #endif |
| 676 | eval = ENOENT; |
| 677 | } |
| 678 | |
| 679 | done: |
| 680 | if (eval == 0) { |
| 681 | uap->sysmsg_result = IXSEQ_TO_IPCID(semid, |
| 682 | sema[semid].sem_perm); |
| 683 | } |
| 684 | rel_mplock(); |
| 685 | return(eval); |
| 686 | } |
| 687 | |
| 688 | /* |
| 689 | * MPALMOSTSAFE |
| 690 | */ |
| 691 | int |
| 692 | sys_semop(struct semop_args *uap) |
| 693 | { |
| 694 | struct thread *td = curthread; |
| 695 | int semid = uap->semid; |
| 696 | u_int nsops = uap->nsops; |
| 697 | struct sembuf sops[MAX_SOPS]; |
| 698 | struct semid_ds *semaptr; |
| 699 | struct sembuf *sopptr; |
| 700 | struct sem *semptr; |
| 701 | struct sem_undo *suptr = NULL; |
| 702 | int i, j, eval; |
| 703 | int do_wakeup, do_undos; |
| 704 | |
| 705 | #ifdef SEM_DEBUG |
| 706 | kprintf("call to semop(%d, 0x%x, %u)\n", semid, sops, nsops); |
| 707 | #endif |
| 708 | |
| 709 | if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) |
| 710 | return (ENOSYS); |
| 711 | |
| 712 | get_mplock(); |
| 713 | semid = IPCID_TO_IX(semid); /* Convert back to zero origin */ |
| 714 | |
| 715 | if (semid < 0 || semid >= seminfo.semmni) { |
| 716 | eval = EINVAL; |
| 717 | goto done; |
| 718 | } |
| 719 | |
| 720 | semaptr = &sema[semid]; |
| 721 | if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0) { |
| 722 | eval = EINVAL; |
| 723 | goto done; |
| 724 | } |
| 725 | if (semaptr->sem_perm.seq != IPCID_TO_SEQ(uap->semid)) { |
| 726 | eval = EINVAL; |
| 727 | goto done; |
| 728 | } |
| 729 | |
| 730 | if ((eval = ipcperm(td->td_proc, &semaptr->sem_perm, IPC_W))) { |
| 731 | #ifdef SEM_DEBUG |
| 732 | kprintf("eval = %d from ipaccess\n", eval); |
| 733 | #endif |
| 734 | goto done; |
| 735 | } |
| 736 | |
| 737 | if (nsops > MAX_SOPS) { |
| 738 | #ifdef SEM_DEBUG |
| 739 | kprintf("too many sops (max=%d, nsops=%u)\n", MAX_SOPS, nsops); |
| 740 | #endif |
| 741 | eval = E2BIG; |
| 742 | goto done; |
| 743 | } |
| 744 | |
| 745 | if ((eval = copyin(uap->sops, &sops, nsops * sizeof(sops[0]))) != 0) { |
| 746 | #ifdef SEM_DEBUG |
| 747 | kprintf("eval = %d from copyin(%08x, %08x, %u)\n", eval, |
| 748 | uap->sops, &sops, nsops * sizeof(sops[0])); |
| 749 | #endif |
| 750 | goto done; |
| 751 | } |
| 752 | |
| 753 | /* |
| 754 | * Loop trying to satisfy the vector of requests. |
| 755 | * If we reach a point where we must wait, any requests already |
| 756 | * performed are rolled back and we go to sleep until some other |
| 757 | * process wakes us up. At this point, we start all over again. |
| 758 | * |
| 759 | * This ensures that from the perspective of other tasks, a set |
| 760 | * of requests is atomic (never partially satisfied). |
| 761 | */ |
| 762 | do_undos = 0; |
| 763 | |
| 764 | for (;;) { |
| 765 | do_wakeup = 0; |
| 766 | |
| 767 | for (i = 0; i < nsops; i++) { |
| 768 | sopptr = &sops[i]; |
| 769 | |
| 770 | if (sopptr->sem_num >= semaptr->sem_nsems) { |
| 771 | eval = EFBIG; |
| 772 | goto done; |
| 773 | } |
| 774 | |
| 775 | semptr = &semaptr->sem_base[sopptr->sem_num]; |
| 776 | |
| 777 | #ifdef SEM_DEBUG |
| 778 | kprintf("semop: semaptr=%x, sem_base=%x, semptr=%x, sem[%d]=%d : op=%d, flag=%s\n", |
| 779 | semaptr, semaptr->sem_base, semptr, |
| 780 | sopptr->sem_num, semptr->semval, sopptr->sem_op, |
| 781 | (sopptr->sem_flg & IPC_NOWAIT) ? "nowait" : "wait"); |
| 782 | #endif |
| 783 | |
| 784 | if (sopptr->sem_op < 0) { |
| 785 | if (semptr->semval + sopptr->sem_op < 0) { |
| 786 | #ifdef SEM_DEBUG |
| 787 | kprintf("semop: can't do it now\n"); |
| 788 | #endif |
| 789 | break; |
| 790 | } else { |
| 791 | semptr->semval += sopptr->sem_op; |
| 792 | if (semptr->semval == 0 && |
| 793 | semptr->semzcnt > 0) |
| 794 | do_wakeup = 1; |
| 795 | } |
| 796 | if (sopptr->sem_flg & SEM_UNDO) |
| 797 | do_undos = 1; |
| 798 | } else if (sopptr->sem_op == 0) { |
| 799 | if (semptr->semval > 0) { |
| 800 | #ifdef SEM_DEBUG |
| 801 | kprintf("semop: not zero now\n"); |
| 802 | #endif |
| 803 | break; |
| 804 | } |
| 805 | } else { |
| 806 | if (semptr->semncnt > 0) |
| 807 | do_wakeup = 1; |
| 808 | semptr->semval += sopptr->sem_op; |
| 809 | if (sopptr->sem_flg & SEM_UNDO) |
| 810 | do_undos = 1; |
| 811 | } |
| 812 | } |
| 813 | |
| 814 | /* |
| 815 | * Did we get through the entire vector? |
| 816 | */ |
| 817 | if (i >= nsops) |
| 818 | goto donex; |
| 819 | |
| 820 | /* |
| 821 | * No ... rollback anything that we've already done |
| 822 | */ |
| 823 | #ifdef SEM_DEBUG |
| 824 | kprintf("semop: rollback 0 through %d\n", i-1); |
| 825 | #endif |
| 826 | for (j = 0; j < i; j++) |
| 827 | semaptr->sem_base[sops[j].sem_num].semval -= |
| 828 | sops[j].sem_op; |
| 829 | |
| 830 | /* |
| 831 | * If the request that we couldn't satisfy has the |
| 832 | * NOWAIT flag set then return with EAGAIN. |
| 833 | */ |
| 834 | if (sopptr->sem_flg & IPC_NOWAIT) { |
| 835 | eval = EAGAIN; |
| 836 | goto done; |
| 837 | } |
| 838 | |
| 839 | if (sopptr->sem_op == 0) |
| 840 | semptr->semzcnt++; |
| 841 | else |
| 842 | semptr->semncnt++; |
| 843 | |
| 844 | #ifdef SEM_DEBUG |
| 845 | kprintf("semop: good night!\n"); |
| 846 | #endif |
| 847 | eval = tsleep((caddr_t)semaptr, PCATCH, "semwait", 0); |
| 848 | #ifdef SEM_DEBUG |
| 849 | kprintf("semop: good morning (eval=%d)!\n", eval); |
| 850 | #endif |
| 851 | |
| 852 | suptr = NULL; /* sem_undo may have been reallocated */ |
| 853 | |
| 854 | /* return code is checked below, after sem[nz]cnt-- */ |
| 855 | |
| 856 | /* |
| 857 | * Make sure that the semaphore still exists |
| 858 | */ |
| 859 | if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0 || |
| 860 | semaptr->sem_perm.seq != IPCID_TO_SEQ(uap->semid)) { |
| 861 | eval = EIDRM; |
| 862 | goto done; |
| 863 | } |
| 864 | |
| 865 | /* |
| 866 | * The semaphore is still alive. Readjust the count of |
| 867 | * waiting processes. |
| 868 | */ |
| 869 | if (sopptr->sem_op == 0) |
| 870 | semptr->semzcnt--; |
| 871 | else |
| 872 | semptr->semncnt--; |
| 873 | |
| 874 | /* |
| 875 | * Is it really morning, or was our sleep interrupted? |
| 876 | * (Delayed check of tsleep() return code because we |
| 877 | * need to decrement sem[nz]cnt either way.) |
| 878 | */ |
| 879 | if (eval) { |
| 880 | eval = EINTR; |
| 881 | goto done; |
| 882 | } |
| 883 | #ifdef SEM_DEBUG |
| 884 | kprintf("semop: good morning!\n"); |
| 885 | #endif |
| 886 | } |
| 887 | |
| 888 | donex: |
| 889 | /* |
| 890 | * Process any SEM_UNDO requests. |
| 891 | */ |
| 892 | if (do_undos) { |
| 893 | for (i = 0; i < nsops; i++) { |
| 894 | /* |
| 895 | * We only need to deal with SEM_UNDO's for non-zero |
| 896 | * op's. |
| 897 | */ |
| 898 | int adjval; |
| 899 | |
| 900 | if ((sops[i].sem_flg & SEM_UNDO) == 0) |
| 901 | continue; |
| 902 | adjval = sops[i].sem_op; |
| 903 | if (adjval == 0) |
| 904 | continue; |
| 905 | eval = semundo_adjust(td->td_proc, &suptr, semid, |
| 906 | sops[i].sem_num, -adjval); |
| 907 | if (eval == 0) |
| 908 | continue; |
| 909 | |
| 910 | /* |
| 911 | * Oh-Oh! We ran out of either sem_undo's or undo's. |
| 912 | * Rollback the adjustments to this point and then |
| 913 | * rollback the semaphore ups and down so we can return |
| 914 | * with an error with all structures restored. We |
| 915 | * rollback the undo's in the exact reverse order that |
| 916 | * we applied them. This guarantees that we won't run |
| 917 | * out of space as we roll things back out. |
| 918 | */ |
| 919 | for (j = i - 1; j >= 0; j--) { |
| 920 | if ((sops[j].sem_flg & SEM_UNDO) == 0) |
| 921 | continue; |
| 922 | adjval = sops[j].sem_op; |
| 923 | if (adjval == 0) |
| 924 | continue; |
| 925 | if (semundo_adjust(td->td_proc, &suptr, semid, |
| 926 | sops[j].sem_num, adjval) != 0) |
| 927 | panic("semop - can't undo undos"); |
| 928 | } |
| 929 | |
| 930 | for (j = 0; j < nsops; j++) |
| 931 | semaptr->sem_base[sops[j].sem_num].semval -= |
| 932 | sops[j].sem_op; |
| 933 | |
| 934 | #ifdef SEM_DEBUG |
| 935 | kprintf("eval = %d from semundo_adjust\n", eval); |
| 936 | #endif |
| 937 | goto done; |
| 938 | } /* loop through the sops */ |
| 939 | } /* if (do_undos) */ |
| 940 | |
| 941 | /* We're definitely done - set the sempid's */ |
| 942 | for (i = 0; i < nsops; i++) { |
| 943 | sopptr = &sops[i]; |
| 944 | semptr = &semaptr->sem_base[sopptr->sem_num]; |
| 945 | semptr->sempid = td->td_proc->p_pid; |
| 946 | } |
| 947 | |
| 948 | /* Do a wakeup if any semaphore was up'd. */ |
| 949 | if (do_wakeup) { |
| 950 | #ifdef SEM_DEBUG |
| 951 | kprintf("semop: doing wakeup\n"); |
| 952 | #endif |
| 953 | wakeup((caddr_t)semaptr); |
| 954 | #ifdef SEM_DEBUG |
| 955 | kprintf("semop: back from wakeup\n"); |
| 956 | #endif |
| 957 | } |
| 958 | #ifdef SEM_DEBUG |
| 959 | kprintf("semop: done\n"); |
| 960 | #endif |
| 961 | uap->sysmsg_result = 0; |
| 962 | eval = 0; |
| 963 | done: |
| 964 | rel_mplock(); |
| 965 | return(eval); |
| 966 | } |
| 967 | |
| 968 | /* |
| 969 | * Go through the undo structures for this process and apply the adjustments to |
| 970 | * semaphores. |
| 971 | */ |
| 972 | void |
| 973 | semexit(struct proc *p) |
| 974 | { |
| 975 | struct sem_undo *suptr; |
| 976 | struct sem_undo **supptr; |
| 977 | int did_something; |
| 978 | |
| 979 | did_something = 0; |
| 980 | |
| 981 | /* |
| 982 | * Go through the chain of undo vectors looking for one |
| 983 | * associated with this process. |
| 984 | */ |
| 985 | |
| 986 | for (supptr = &semu_list; (suptr = *supptr) != NULL; |
| 987 | supptr = &suptr->un_next) { |
| 988 | if (suptr->un_proc == p) |
| 989 | break; |
| 990 | } |
| 991 | |
| 992 | if (suptr == NULL) |
| 993 | return; |
| 994 | |
| 995 | #ifdef SEM_DEBUG |
| 996 | kprintf("proc @%08x has undo structure with %d entries\n", p, |
| 997 | suptr->un_cnt); |
| 998 | #endif |
| 999 | |
| 1000 | /* |
| 1001 | * If there are any active undo elements then process them. |
| 1002 | */ |
| 1003 | if (suptr->un_cnt > 0) { |
| 1004 | int ix; |
| 1005 | |
| 1006 | for (ix = 0; ix < suptr->un_cnt; ix++) { |
| 1007 | int semid = suptr->un_ent[ix].un_id; |
| 1008 | int semnum = suptr->un_ent[ix].un_num; |
| 1009 | int adjval = suptr->un_ent[ix].un_adjval; |
| 1010 | struct semid_ds *semaptr; |
| 1011 | |
| 1012 | semaptr = &sema[semid]; |
| 1013 | if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0) |
| 1014 | panic("semexit - semid not allocated"); |
| 1015 | if (semnum >= semaptr->sem_nsems) |
| 1016 | panic("semexit - semnum out of range"); |
| 1017 | |
| 1018 | #ifdef SEM_DEBUG |
| 1019 | kprintf("semexit: %08x id=%d num=%d(adj=%d) ; sem=%d\n", |
| 1020 | suptr->un_proc, suptr->un_ent[ix].un_id, |
| 1021 | suptr->un_ent[ix].un_num, |
| 1022 | suptr->un_ent[ix].un_adjval, |
| 1023 | semaptr->sem_base[semnum].semval); |
| 1024 | #endif |
| 1025 | |
| 1026 | if (adjval < 0) { |
| 1027 | if (semaptr->sem_base[semnum].semval < -adjval) |
| 1028 | semaptr->sem_base[semnum].semval = 0; |
| 1029 | else |
| 1030 | semaptr->sem_base[semnum].semval += |
| 1031 | adjval; |
| 1032 | } else |
| 1033 | semaptr->sem_base[semnum].semval += adjval; |
| 1034 | |
| 1035 | wakeup((caddr_t)semaptr); |
| 1036 | #ifdef SEM_DEBUG |
| 1037 | kprintf("semexit: back from wakeup\n"); |
| 1038 | #endif |
| 1039 | } |
| 1040 | } |
| 1041 | |
| 1042 | /* |
| 1043 | * Deallocate the undo vector. |
| 1044 | */ |
| 1045 | #ifdef SEM_DEBUG |
| 1046 | kprintf("removing vector\n"); |
| 1047 | #endif |
| 1048 | suptr->un_proc = NULL; |
| 1049 | *supptr = suptr->un_next; |
| 1050 | } |