FreeBSD kernel kern code
sysv_sem.c
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1 /*-
2  * Implementation of SVID semaphores
3  *
4  * Author: Daniel Boulet
5  *
6  * This software is provided ``AS IS'' without any warranties of any kind.
7  */
8 /*-
9  * Copyright (c) 2003-2005 McAfee, Inc.
10  * All rights reserved.
11  *
12  * This software was developed for the FreeBSD Project in part by McAfee
13  * Research, the Security Research Division of McAfee, Inc under DARPA/SPAWAR
14  * contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS research
15  * program.
16  *
17  * Redistribution and use in source and binary forms, with or without
18  * modification, are permitted provided that the following conditions
19  * are met:
20  * 1. Redistributions of source code must retain the above copyright
21  * notice, this list of conditions and the following disclaimer.
22  * 2. Redistributions in binary form must reproduce the above copyright
23  * notice, this list of conditions and the following disclaimer in the
24  * documentation and/or other materials provided with the distribution.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  */
38 
39 #include <sys/cdefs.h>
40 __FBSDID("$BSDSUniX$");
41 
42 #include "opt_compat.h"
43 #include "opt_sysvipc.h"
44 
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/sysproto.h>
48 #include <sys/eventhandler.h>
49 #include <sys/kernel.h>
50 #include <sys/proc.h>
51 #include <sys/lock.h>
52 #include <sys/module.h>
53 #include <sys/mutex.h>
54 #include <sys/racct.h>
55 #include <sys/sem.h>
56 #include <sys/syscall.h>
57 #include <sys/syscallsubr.h>
58 #include <sys/sysent.h>
59 #include <sys/sysctl.h>
60 #include <sys/uio.h>
61 #include <sys/malloc.h>
62 #include <sys/jail.h>
63 
64 #include <security/mac/mac_framework.h>
65 
66 FEATURE(sysv_sem, "System V semaphores support");
67 
68 static MALLOC_DEFINE(M_SEM, "sem", "SVID compatible semaphores");
69 
70 #ifdef SEM_DEBUG
71 #define DPRINTF(a) printf a
72 #else
73 #define DPRINTF(a)
74 #endif
75 
76 static int seminit(void);
77 static int sysvsem_modload(struct module *, int, void *);
78 static int semunload(void);
79 static void semexit_myhook(void *arg, struct proc *p);
80 static int sysctl_sema(SYSCTL_HANDLER_ARGS);
81 static int semvalid(int semid, struct semid_kernel *semakptr);
82 
83 #ifndef _SYS_SYSPROTO_H_
84 struct __semctl_args;
85 int __semctl(struct thread *td, struct __semctl_args *uap);
86 struct semget_args;
87 int semget(struct thread *td, struct semget_args *uap);
88 struct semop_args;
89 int semop(struct thread *td, struct semop_args *uap);
90 #endif
91 
92 static struct sem_undo *semu_alloc(struct thread *td);
93 static int semundo_adjust(struct thread *td, struct sem_undo **supptr,
94  int semid, int semseq, int semnum, int adjval);
95 static void semundo_clear(int semid, int semnum);
96 
97 static struct mtx sem_mtx; /* semaphore global lock */
98 static struct mtx sem_undo_mtx;
99 static int semtot = 0;
100 static struct semid_kernel *sema; /* semaphore id pool */
101 static struct mtx *sema_mtx; /* semaphore id pool mutexes*/
102 static struct sem *sem; /* semaphore pool */
103 LIST_HEAD(, sem_undo) semu_list; /* list of active undo structures */
104 LIST_HEAD(, sem_undo) semu_free_list; /* list of free undo structures */
105 static int *semu; /* undo structure pool */
106 static eventhandler_tag semexit_tag;
107 
108 #define SEMUNDO_MTX sem_undo_mtx
109 #define SEMUNDO_LOCK() mtx_lock(&SEMUNDO_MTX);
110 #define SEMUNDO_UNLOCK() mtx_unlock(&SEMUNDO_MTX);
111 #define SEMUNDO_LOCKASSERT(how) mtx_assert(&SEMUNDO_MTX, (how));
112 
113 struct sem {
114  u_short semval; /* semaphore value */
115  pid_t sempid; /* pid of last operation */
116  u_short semncnt; /* # awaiting semval > cval */
117  u_short semzcnt; /* # awaiting semval = 0 */
118 };
119 
120 /*
121  * Undo structure (one per process)
122  */
123 struct sem_undo {
124  LIST_ENTRY(sem_undo) un_next; /* ptr to next active undo structure */
125  struct proc *un_proc; /* owner of this structure */
126  short un_cnt; /* # of active entries */
127  struct undo {
128  short un_adjval; /* adjust on exit values */
129  short un_num; /* semaphore # */
130  int un_id; /* semid */
131  unsigned short un_seq;
132  } un_ent[1]; /* undo entries */
133 };
134 
135 /*
136  * Configuration parameters
137  */
138 #ifndef SEMMNI
139 #define SEMMNI 50 /* # of semaphore identifiers */
140 #endif
141 #ifndef SEMMNS
142 #define SEMMNS 340 /* # of semaphores in system */
143 #endif
144 #ifndef SEMUME
145 #define SEMUME 50 /* max # of undo entries per process */
146 #endif
147 #ifndef SEMMNU
148 #define SEMMNU 150 /* # of undo structures in system */
149 #endif
150 
151 /* shouldn't need tuning */
152 #ifndef SEMMSL
153 #define SEMMSL SEMMNS /* max # of semaphores per id */
154 #endif
155 #ifndef SEMOPM
156 #define SEMOPM 100 /* max # of operations per semop call */
157 #endif
158 
159 #define SEMVMX 32767 /* semaphore maximum value */
160 #define SEMAEM 16384 /* adjust on exit max value */
161 
162 /*
163  * Due to the way semaphore memory is allocated, we have to ensure that
164  * SEMUSZ is properly aligned.
165  */
166 
167 #define SEM_ALIGN(bytes) (((bytes) + (sizeof(long) - 1)) & ~(sizeof(long) - 1))
168 
169 /* actual size of an undo structure */
170 #define SEMUSZ SEM_ALIGN(offsetof(struct sem_undo, un_ent[SEMUME]))
171 
172 /*
173  * Macro to find a particular sem_undo vector
174  */
175 #define SEMU(ix) \
176  ((struct sem_undo *)(((intptr_t)semu)+ix * seminfo.semusz))
177 
178 /*
179  * semaphore info struct
180  */
181 struct seminfo seminfo = {
182  SEMMNI, /* # of semaphore identifiers */
183  SEMMNS, /* # of semaphores in system */
184  SEMMNU, /* # of undo structures in system */
185  SEMMSL, /* max # of semaphores per id */
186  SEMOPM, /* max # of operations per semop call */
187  SEMUME, /* max # of undo entries per process */
188  SEMUSZ, /* size in bytes of undo structure */
189  SEMVMX, /* semaphore maximum value */
190  SEMAEM /* adjust on exit max value */
191 };
192 
193 SYSCTL_INT(_kern_ipc, OID_AUTO, semmni, CTLFLAG_RDTUN, &seminfo.semmni, 0,
194  "Number of semaphore identifiers");
195 SYSCTL_INT(_kern_ipc, OID_AUTO, semmns, CTLFLAG_RDTUN, &seminfo.semmns, 0,
196  "Maximum number of semaphores in the system");
197 SYSCTL_INT(_kern_ipc, OID_AUTO, semmnu, CTLFLAG_RDTUN, &seminfo.semmnu, 0,
198  "Maximum number of undo structures in the system");
199 SYSCTL_INT(_kern_ipc, OID_AUTO, semmsl, CTLFLAG_RW, &seminfo.semmsl, 0,
200  "Max semaphores per id");
201 SYSCTL_INT(_kern_ipc, OID_AUTO, semopm, CTLFLAG_RDTUN, &seminfo.semopm, 0,
202  "Max operations per semop call");
203 SYSCTL_INT(_kern_ipc, OID_AUTO, semume, CTLFLAG_RDTUN, &seminfo.semume, 0,
204  "Max undo entries per process");
205 SYSCTL_INT(_kern_ipc, OID_AUTO, semusz, CTLFLAG_RDTUN, &seminfo.semusz, 0,
206  "Size in bytes of undo structure");
207 SYSCTL_INT(_kern_ipc, OID_AUTO, semvmx, CTLFLAG_RW, &seminfo.semvmx, 0,
208  "Semaphore maximum value");
209 SYSCTL_INT(_kern_ipc, OID_AUTO, semaem, CTLFLAG_RW, &seminfo.semaem, 0,
210  "Adjust on exit max value");
211 SYSCTL_PROC(_kern_ipc, OID_AUTO, sema, CTLTYPE_OPAQUE | CTLFLAG_RD,
212  NULL, 0, sysctl_sema, "", "Semaphore id pool");
213 
214 static struct syscall_helper_data sem_syscalls[] = {
215  SYSCALL_INIT_HELPER(__semctl),
216  SYSCALL_INIT_HELPER(semget),
217  SYSCALL_INIT_HELPER(semop),
218 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
219  defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
220  SYSCALL_INIT_HELPER(semsys),
221  SYSCALL_INIT_HELPER_COMPAT(freebsd7___semctl),
222 #endif
223  SYSCALL_INIT_LAST
224 };
225 
226 #ifdef COMPAT_32BIT
227 #include <compat/compat32bit/compat32bit.h>
228 #include <compat/compat32bit/compat32bit_ipc.h>
229 #include <compat/compat32bit/compat32bit_proto.h>
230 #include <compat/compat32bit/compat32bit_signal.h>
231 #include <compat/compat32bit/compat32bit_syscall.h>
232 #include <compat/compat32bit/compat32bit_util.h>
233 
234 static struct syscall_helper_data sem32_syscalls[] = {
235  SYSCALL32_INIT_HELPER(compat32bit_semctl),
236  SYSCALL32_INIT_HELPER_COMPAT(semget),
237  SYSCALL32_INIT_HELPER_COMPAT(semop),
238  SYSCALL32_INIT_HELPER(compat32bit_semsys),
239 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
240  defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
241  SYSCALL32_INIT_HELPER(freebsd7_compat32bit_semctl),
242 #endif
243  SYSCALL_INIT_LAST
244 };
245 #endif
246 
247 static int
248 seminit(void)
249 {
250  int i, error;
251 
252  TUNABLE_INT_FETCH("kern.ipc.semmni", &seminfo.semmni);
253  TUNABLE_INT_FETCH("kern.ipc.semmns", &seminfo.semmns);
254  TUNABLE_INT_FETCH("kern.ipc.semmnu", &seminfo.semmnu);
255  TUNABLE_INT_FETCH("kern.ipc.semmsl", &seminfo.semmsl);
256  TUNABLE_INT_FETCH("kern.ipc.semopm", &seminfo.semopm);
257  TUNABLE_INT_FETCH("kern.ipc.semume", &seminfo.semume);
258  TUNABLE_INT_FETCH("kern.ipc.semusz", &seminfo.semusz);
259  TUNABLE_INT_FETCH("kern.ipc.semvmx", &seminfo.semvmx);
260  TUNABLE_INT_FETCH("kern.ipc.semaem", &seminfo.semaem);
261 
262  sem = malloc(sizeof(struct sem) * seminfo.semmns, M_SEM, M_WAITOK);
263  sema = malloc(sizeof(struct semid_kernel) * seminfo.semmni, M_SEM,
264  M_WAITOK);
265  sema_mtx = malloc(sizeof(struct mtx) * seminfo.semmni, M_SEM,
266  M_WAITOK | M_ZERO);
267  semu = malloc(seminfo.semmnu * seminfo.semusz, M_SEM, M_WAITOK);
268 
269  for (i = 0; i < seminfo.semmni; i++) {
270  sema[i].u.sem_base = 0;
271  sema[i].u.sem_perm.mode = 0;
272  sema[i].u.sem_perm.seq = 0;
273 #ifdef MAC
274  mac_sysvsem_init(&sema[i]);
275 #endif
276  }
277  for (i = 0; i < seminfo.semmni; i++)
278  mtx_init(&sema_mtx[i], "semid", NULL, MTX_DEF);
279  LIST_INIT(&semu_free_list);
280  for (i = 0; i < seminfo.semmnu; i++) {
281  struct sem_undo *suptr = SEMU(i);
282  suptr->un_proc = NULL;
283  LIST_INSERT_HEAD(&semu_free_list, suptr, un_next);
284  }
285  LIST_INIT(&semu_list);
286  mtx_init(&sem_mtx, "sem", NULL, MTX_DEF);
287  mtx_init(&sem_undo_mtx, "semu", NULL, MTX_DEF);
288  semexit_tag = EVENTHANDLER_REGISTER(process_exit, semexit_myhook, NULL,
289  EVENTHANDLER_PRI_ANY);
290 
291  error = syscall_helper_register(sem_syscalls);
292  if (error != 0)
293  return (error);
294 #ifdef COMPAT_32BIT
295  error = syscall32_helper_register(sem32_syscalls);
296  if (error != 0)
297  return (error);
298 #endif
299  return (0);
300 }
301 
302 static int
303 semunload(void)
304 {
305  int i;
306 
307  /* XXXKIB */
308  if (semtot != 0)
309  return (EBUSY);
310 
311 #ifdef COMPAT_32BIT
312  syscall32_helper_unregister(sem32_syscalls);
313 #endif
314  syscall_helper_unregister(sem_syscalls);
315  EVENTHANDLER_DEREGISTER(process_exit, semexit_tag);
316 #ifdef MAC
317  for (i = 0; i < seminfo.semmni; i++)
318  mac_sysvsem_destroy(&sema[i]);
319 #endif
320  free(sem, M_SEM);
321  free(sema, M_SEM);
322  free(semu, M_SEM);
323  for (i = 0; i < seminfo.semmni; i++)
324  mtx_destroy(&sema_mtx[i]);
325  free(sema_mtx, M_SEM);
326  mtx_destroy(&sem_mtx);
327  mtx_destroy(&sem_undo_mtx);
328  return (0);
329 }
330 
331 static int
332 sysvsem_modload(struct module *module, int cmd, void *arg)
333 {
334  int error = 0;
335 
336  switch (cmd) {
337  case MOD_LOAD:
338  error = seminit();
339  if (error != 0)
340  semunload();
341  break;
342  case MOD_UNLOAD:
343  error = semunload();
344  break;
345  case MOD_SHUTDOWN:
346  break;
347  default:
348  error = EINVAL;
349  break;
350  }
351  return (error);
352 }
353 
354 static moduledata_t sysvsem_mod = {
355  "sysvsem",
356  &sysvsem_modload,
357  NULL
358 };
359 
360 DECLARE_MODULE(sysvsem, sysvsem_mod, SI_SUB_SYSV_SEM, SI_ORDER_FIRST);
361 MODULE_VERSION(sysvsem, 1);
362 
363 /*
364  * Allocate a new sem_undo structure for a process
365  * (returns ptr to structure or NULL if no more room)
366  */
367 
368 static struct sem_undo *
369 semu_alloc(struct thread *td)
370 {
371  struct sem_undo *suptr;
372 
373  SEMUNDO_LOCKASSERT(MA_OWNED);
374  if ((suptr = LIST_FIRST(&semu_free_list)) == NULL)
375  return (NULL);
376  LIST_REMOVE(suptr, un_next);
377  LIST_INSERT_HEAD(&semu_list, suptr, un_next);
378  suptr->un_cnt = 0;
379  suptr->un_proc = td->td_proc;
380  return (suptr);
381 }
382 
383 static int
384 semu_try_free(struct sem_undo *suptr)
385 {
386 
387  SEMUNDO_LOCKASSERT(MA_OWNED);
388 
389  if (suptr->un_cnt != 0)
390  return (0);
391  LIST_REMOVE(suptr, un_next);
392  LIST_INSERT_HEAD(&semu_free_list, suptr, un_next);
393  return (1);
394 }
395 
396 /*
397  * Adjust a particular entry for a particular proc
398  */
399 
400 static int
401 semundo_adjust(struct thread *td, struct sem_undo **supptr, int semid,
402  int semseq, int semnum, int adjval)
403 {
404  struct proc *p = td->td_proc;
405  struct sem_undo *suptr;
406  struct undo *sunptr;
407  int i;
408 
409  SEMUNDO_LOCKASSERT(MA_OWNED);
410  /* Look for and remember the sem_undo if the caller doesn't provide
411  it */
412 
413  suptr = *supptr;
414  if (suptr == NULL) {
415  LIST_FOREACH(suptr, &semu_list, un_next) {
416  if (suptr->un_proc == p) {
417  *supptr = suptr;
418  break;
419  }
420  }
421  if (suptr == NULL) {
422  if (adjval == 0)
423  return(0);
424  suptr = semu_alloc(td);
425  if (suptr == NULL)
426  return (ENOSPC);
427  *supptr = suptr;
428  }
429  }
430 
431  /*
432  * Look for the requested entry and adjust it (delete if adjval becomes
433  * 0).
434  */
435  sunptr = &suptr->un_ent[0];
436  for (i = 0; i < suptr->un_cnt; i++, sunptr++) {
437  if (sunptr->un_id != semid || sunptr->un_num != semnum)
438  continue;
439  if (adjval != 0) {
440  adjval += sunptr->un_adjval;
441  if (adjval > seminfo.semaem || adjval < -seminfo.semaem)
442  return (ERANGE);
443  }
444  sunptr->un_adjval = adjval;
445  if (sunptr->un_adjval == 0) {
446  suptr->un_cnt--;
447  if (i < suptr->un_cnt)
448  suptr->un_ent[i] =
449  suptr->un_ent[suptr->un_cnt];
450  if (suptr->un_cnt == 0)
451  semu_try_free(suptr);
452  }
453  return (0);
454  }
455 
456  /* Didn't find the right entry - create it */
457  if (adjval == 0)
458  return (0);
459  if (adjval > seminfo.semaem || adjval < -seminfo.semaem)
460  return (ERANGE);
461  if (suptr->un_cnt != seminfo.semume) {
462  sunptr = &suptr->un_ent[suptr->un_cnt];
463  suptr->un_cnt++;
464  sunptr->un_adjval = adjval;
465  sunptr->un_id = semid;
466  sunptr->un_num = semnum;
467  sunptr->un_seq = semseq;
468  } else
469  return (EINVAL);
470  return (0);
471 }
472 
473 static void
474 semundo_clear(int semid, int semnum)
475 {
476  struct sem_undo *suptr, *suptr1;
477  struct undo *sunptr;
478  int i;
479 
480  SEMUNDO_LOCKASSERT(MA_OWNED);
481  LIST_FOREACH_SAFE(suptr, &semu_list, un_next, suptr1) {
482  sunptr = &suptr->un_ent[0];
483  for (i = 0; i < suptr->un_cnt; i++, sunptr++) {
484  if (sunptr->un_id != semid)
485  continue;
486  if (semnum == -1 || sunptr->un_num == semnum) {
487  suptr->un_cnt--;
488  if (i < suptr->un_cnt) {
489  suptr->un_ent[i] =
490  suptr->un_ent[suptr->un_cnt];
491  continue;
492  }
493  semu_try_free(suptr);
494  }
495  if (semnum != -1)
496  break;
497  }
498  }
499 }
500 
501 static int
502 semvalid(int semid, struct semid_kernel *semakptr)
503 {
504 
505  return ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0 ||
506  semakptr->u.sem_perm.seq != IPCID_TO_SEQ(semid) ? EINVAL : 0);
507 }
508 
509 /*
510  * Note that the user-mode half of this passes a union, not a pointer.
511  */
512 #ifndef _SYS_SYSPROTO_H_
513 struct __semctl_args {
514  int semid;
515  int semnum;
516  int cmd;
517  union semun *arg;
518 };
519 #endif
520 int
521 sys___semctl(struct thread *td, struct __semctl_args *uap)
522 {
523  struct semid_ds dsbuf;
524  union semun arg, semun;
525  register_t rval;
526  int error;
527 
528  switch (uap->cmd) {
529  case SEM_STAT:
530  case IPC_SET:
531  case IPC_STAT:
532  case GETALL:
533  case SETVAL:
534  case SETALL:
535  error = copyin(uap->arg, &arg, sizeof(arg));
536  if (error)
537  return (error);
538  break;
539  }
540 
541  switch (uap->cmd) {
542  case SEM_STAT:
543  case IPC_STAT:
544  semun.buf = &dsbuf;
545  break;
546  case IPC_SET:
547  error = copyin(arg.buf, &dsbuf, sizeof(dsbuf));
548  if (error)
549  return (error);
550  semun.buf = &dsbuf;
551  break;
552  case GETALL:
553  case SETALL:
554  semun.array = arg.array;
555  break;
556  case SETVAL:
557  semun.val = arg.val;
558  break;
559  }
560 
561  error = kern_semctl(td, uap->semid, uap->semnum, uap->cmd, &semun,
562  &rval);
563  if (error)
564  return (error);
565 
566  switch (uap->cmd) {
567  case SEM_STAT:
568  case IPC_STAT:
569  error = copyout(&dsbuf, arg.buf, sizeof(dsbuf));
570  break;
571  }
572 
573  if (error == 0)
574  td->td_retval[0] = rval;
575  return (error);
576 }
577 
578 int
579 kern_semctl(struct thread *td, int semid, int semnum, int cmd,
580  union semun *arg, register_t *rval)
581 {
582  u_short *array;
583  struct ucred *cred = td->td_ucred;
584  int i, error;
585  struct semid_ds *sbuf;
586  struct semid_kernel *semakptr;
587  struct mtx *sema_mtxp;
588  u_short usval, count;
589  int semidx;
590 
591  DPRINTF(("call to semctl(%d, %d, %d, 0x%p)\n",
592  semid, semnum, cmd, arg));
593  if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
594  return (ENOSYS);
595 
596  array = NULL;
597 
598  switch(cmd) {
599  case SEM_STAT:
600  /*
601  * For this command we assume semid is an array index
602  * rather than an IPC id.
603  */
604  if (semid < 0 || semid >= seminfo.semmni)
605  return (EINVAL);
606  semakptr = &sema[semid];
607  sema_mtxp = &sema_mtx[semid];
608  mtx_lock(sema_mtxp);
609  if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0) {
610  error = EINVAL;
611  goto done2;
612  }
613  if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
614  goto done2;
615 #ifdef MAC
616  error = mac_sysvsem_check_semctl(cred, semakptr, cmd);
617  if (error != 0)
618  goto done2;
619 #endif
620  bcopy(&semakptr->u, arg->buf, sizeof(struct semid_ds));
621  *rval = IXSEQ_TO_IPCID(semid, semakptr->u.sem_perm);
622  mtx_unlock(sema_mtxp);
623  return (0);
624  }
625 
626  semidx = IPCID_TO_IX(semid);
627  if (semidx < 0 || semidx >= seminfo.semmni)
628  return (EINVAL);
629 
630  semakptr = &sema[semidx];
631  sema_mtxp = &sema_mtx[semidx];
632  if (cmd == IPC_RMID)
633  mtx_lock(&sem_mtx);
634  mtx_lock(sema_mtxp);
635 #ifdef MAC
636  error = mac_sysvsem_check_semctl(cred, semakptr, cmd);
637  if (error != 0)
638  goto done2;
639 #endif
640 
641  error = 0;
642  *rval = 0;
643 
644  switch (cmd) {
645  case IPC_RMID:
646  if ((error = semvalid(semid, semakptr)) != 0)
647  goto done2;
648  if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_M)))
649  goto done2;
650  semakptr->u.sem_perm.cuid = cred->cr_uid;
651  semakptr->u.sem_perm.uid = cred->cr_uid;
652  semakptr->u.sem_perm.mode = 0;
653  racct_sub_cred(semakptr->cred, RACCT_NSEM, semakptr->u.sem_nsems);
654  crfree(semakptr->cred);
655  semakptr->cred = NULL;
656  SEMUNDO_LOCK();
657  semundo_clear(semidx, -1);
658  SEMUNDO_UNLOCK();
659 #ifdef MAC
660  mac_sysvsem_cleanup(semakptr);
661 #endif
662  wakeup(semakptr);
663  for (i = 0; i < seminfo.semmni; i++) {
664  if ((sema[i].u.sem_perm.mode & SEM_ALLOC) &&
665  sema[i].u.sem_base > semakptr->u.sem_base)
666  mtx_lock_flags(&sema_mtx[i], LOP_DUPOK);
667  }
668  for (i = semakptr->u.sem_base - sem; i < semtot; i++)
669  sem[i] = sem[i + semakptr->u.sem_nsems];
670  for (i = 0; i < seminfo.semmni; i++) {
671  if ((sema[i].u.sem_perm.mode & SEM_ALLOC) &&
672  sema[i].u.sem_base > semakptr->u.sem_base) {
673  sema[i].u.sem_base -= semakptr->u.sem_nsems;
674  mtx_unlock(&sema_mtx[i]);
675  }
676  }
677  semtot -= semakptr->u.sem_nsems;
678  break;
679 
680  case IPC_SET:
681  if ((error = semvalid(semid, semakptr)) != 0)
682  goto done2;
683  if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_M)))
684  goto done2;
685  sbuf = arg->buf;
686  semakptr->u.sem_perm.uid = sbuf->sem_perm.uid;
687  semakptr->u.sem_perm.gid = sbuf->sem_perm.gid;
688  semakptr->u.sem_perm.mode = (semakptr->u.sem_perm.mode &
689  ~0777) | (sbuf->sem_perm.mode & 0777);
690  semakptr->u.sem_ctime = time_second;
691  break;
692 
693  case IPC_STAT:
694  if ((error = semvalid(semid, semakptr)) != 0)
695  goto done2;
696  if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
697  goto done2;
698  bcopy(&semakptr->u, arg->buf, sizeof(struct semid_ds));
699  break;
700 
701  case GETNCNT:
702  if ((error = semvalid(semid, semakptr)) != 0)
703  goto done2;
704  if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
705  goto done2;
706  if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
707  error = EINVAL;
708  goto done2;
709  }
710  *rval = semakptr->u.sem_base[semnum].semncnt;
711  break;
712 
713  case GETPID:
714  if ((error = semvalid(semid, semakptr)) != 0)
715  goto done2;
716  if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
717  goto done2;
718  if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
719  error = EINVAL;
720  goto done2;
721  }
722  *rval = semakptr->u.sem_base[semnum].sempid;
723  break;
724 
725  case GETVAL:
726  if ((error = semvalid(semid, semakptr)) != 0)
727  goto done2;
728  if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
729  goto done2;
730  if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
731  error = EINVAL;
732  goto done2;
733  }
734  *rval = semakptr->u.sem_base[semnum].semval;
735  break;
736 
737  case GETALL:
738  /*
739  * Unfortunately, callers of this function don't know
740  * in advance how many semaphores are in this set.
741  * While we could just allocate the maximum size array
742  * and pass the actual size back to the caller, that
743  * won't work for SETALL since we can't copyin() more
744  * data than the user specified as we may return a
745  * spurious EFAULT.
746  *
747  * Note that the number of semaphores in a set is
748  * fixed for the life of that set. The only way that
749  * the 'count' could change while are blocked in
750  * malloc() is if this semaphore set were destroyed
751  * and a new one created with the same index.
752  * However, semvalid() will catch that due to the
753  * sequence number unless exactly 0x8000 (or a
754  * multiple thereof) semaphore sets for the same index
755  * are created and destroyed while we are in malloc!
756  *
757  */
758  count = semakptr->u.sem_nsems;
759  mtx_unlock(sema_mtxp);
760  array = malloc(sizeof(*array) * count, M_TEMP, M_WAITOK);
761  mtx_lock(sema_mtxp);
762  if ((error = semvalid(semid, semakptr)) != 0)
763  goto done2;
764  KASSERT(count == semakptr->u.sem_nsems, ("nsems changed"));
765  if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
766  goto done2;
767  for (i = 0; i < semakptr->u.sem_nsems; i++)
768  array[i] = semakptr->u.sem_base[i].semval;
769  mtx_unlock(sema_mtxp);
770  error = copyout(array, arg->array, count * sizeof(*array));
771  mtx_lock(sema_mtxp);
772  break;
773 
774  case GETZCNT:
775  if ((error = semvalid(semid, semakptr)) != 0)
776  goto done2;
777  if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
778  goto done2;
779  if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
780  error = EINVAL;
781  goto done2;
782  }
783  *rval = semakptr->u.sem_base[semnum].semzcnt;
784  break;
785 
786  case SETVAL:
787  if ((error = semvalid(semid, semakptr)) != 0)
788  goto done2;
789  if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_W)))
790  goto done2;
791  if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
792  error = EINVAL;
793  goto done2;
794  }
795  if (arg->val < 0 || arg->val > seminfo.semvmx) {
796  error = ERANGE;
797  goto done2;
798  }
799  semakptr->u.sem_base[semnum].semval = arg->val;
800  SEMUNDO_LOCK();
801  semundo_clear(semidx, semnum);
802  SEMUNDO_UNLOCK();
803  wakeup(semakptr);
804  break;
805 
806  case SETALL:
807  /*
808  * See comment on GETALL for why 'count' shouldn't change
809  * and why we require a userland buffer.
810  */
811  count = semakptr->u.sem_nsems;
812  mtx_unlock(sema_mtxp);
813  array = malloc(sizeof(*array) * count, M_TEMP, M_WAITOK);
814  error = copyin(arg->array, array, count * sizeof(*array));
815  mtx_lock(sema_mtxp);
816  if (error)
817  break;
818  if ((error = semvalid(semid, semakptr)) != 0)
819  goto done2;
820  KASSERT(count == semakptr->u.sem_nsems, ("nsems changed"));
821  if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_W)))
822  goto done2;
823  for (i = 0; i < semakptr->u.sem_nsems; i++) {
824  usval = array[i];
825  if (usval > seminfo.semvmx) {
826  error = ERANGE;
827  break;
828  }
829  semakptr->u.sem_base[i].semval = usval;
830  }
831  SEMUNDO_LOCK();
832  semundo_clear(semidx, -1);
833  SEMUNDO_UNLOCK();
834  wakeup(semakptr);
835  break;
836 
837  default:
838  error = EINVAL;
839  break;
840  }
841 
842 done2:
843  mtx_unlock(sema_mtxp);
844  if (cmd == IPC_RMID)
845  mtx_unlock(&sem_mtx);
846  if (array != NULL)
847  free(array, M_TEMP);
848  return(error);
849 }
850 
851 #ifndef _SYS_SYSPROTO_H_
852 struct semget_args {
853  key_t key;
854  int nsems;
855  int semflg;
856 };
857 #endif
858 int
859 sys_semget(struct thread *td, struct semget_args *uap)
860 {
861  int semid, error = 0;
862  int key = uap->key;
863  int nsems = uap->nsems;
864  int semflg = uap->semflg;
865  struct ucred *cred = td->td_ucred;
866 
867  DPRINTF(("semget(0x%x, %d, 0%o)\n", key, nsems, semflg));
868  if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
869  return (ENOSYS);
870 
871  mtx_lock(&sem_mtx);
872  if (key != IPC_PRIVATE) {
873  for (semid = 0; semid < seminfo.semmni; semid++) {
874  if ((sema[semid].u.sem_perm.mode & SEM_ALLOC) &&
875  sema[semid].u.sem_perm.key == key)
876  break;
877  }
878  if (semid < seminfo.semmni) {
879  DPRINTF(("found public key\n"));
880  if ((error = ipcperm(td, &sema[semid].u.sem_perm,
881  semflg & 0700))) {
882  goto done2;
883  }
884  if (nsems > 0 && sema[semid].u.sem_nsems < nsems) {
885  DPRINTF(("too small\n"));
886  error = EINVAL;
887  goto done2;
888  }
889  if ((semflg & IPC_CREAT) && (semflg & IPC_EXCL)) {
890  DPRINTF(("not exclusive\n"));
891  error = EEXIST;
892  goto done2;
893  }
894 #ifdef MAC
895  error = mac_sysvsem_check_semget(cred, &sema[semid]);
896  if (error != 0)
897  goto done2;
898 #endif
899  goto found;
900  }
901  }
902 
903  DPRINTF(("need to allocate the semid_kernel\n"));
904  if (key == IPC_PRIVATE || (semflg & IPC_CREAT)) {
905  if (nsems <= 0 || nsems > seminfo.semmsl) {
906  DPRINTF(("nsems out of range (0<%d<=%d)\n", nsems,
907  seminfo.semmsl));
908  error = EINVAL;
909  goto done2;
910  }
911  if (nsems > seminfo.semmns - semtot) {
912  DPRINTF((
913  "not enough semaphores left (need %d, got %d)\n",
914  nsems, seminfo.semmns - semtot));
915  error = ENOSPC;
916  goto done2;
917  }
918  for (semid = 0; semid < seminfo.semmni; semid++) {
919  if ((sema[semid].u.sem_perm.mode & SEM_ALLOC) == 0)
920  break;
921  }
922  if (semid == seminfo.semmni) {
923  DPRINTF(("no more semid_kernel's available\n"));
924  error = ENOSPC;
925  goto done2;
926  }
927 #ifdef RACCT
928  PROC_LOCK(td->td_proc);
929  error = racct_add(td->td_proc, RACCT_NSEM, nsems);
930  PROC_UNLOCK(td->td_proc);
931  if (error != 0) {
932  error = ENOSPC;
933  goto done2;
934  }
935 #endif
936  DPRINTF(("semid %d is available\n", semid));
937  mtx_lock(&sema_mtx[semid]);
938  KASSERT((sema[semid].u.sem_perm.mode & SEM_ALLOC) == 0,
939  ("Lost semaphore %d", semid));
940  sema[semid].u.sem_perm.key = key;
941  sema[semid].u.sem_perm.cuid = cred->cr_uid;
942  sema[semid].u.sem_perm.uid = cred->cr_uid;
943  sema[semid].u.sem_perm.cgid = cred->cr_gid;
944  sema[semid].u.sem_perm.gid = cred->cr_gid;
945  sema[semid].u.sem_perm.mode = (semflg & 0777) | SEM_ALLOC;
946  sema[semid].cred = crhold(cred);
947  sema[semid].u.sem_perm.seq =
948  (sema[semid].u.sem_perm.seq + 1) & 0x7fff;
949  sema[semid].u.sem_nsems = nsems;
950  sema[semid].u.sem_otime = 0;
951  sema[semid].u.sem_ctime = time_second;
952  sema[semid].u.sem_base = &sem[semtot];
953  semtot += nsems;
954  bzero(sema[semid].u.sem_base,
955  sizeof(sema[semid].u.sem_base[0])*nsems);
956 #ifdef MAC
957  mac_sysvsem_create(cred, &sema[semid]);
958 #endif
959  mtx_unlock(&sema_mtx[semid]);
960  DPRINTF(("sembase = %p, next = %p\n",
961  sema[semid].u.sem_base, &sem[semtot]));
962  } else {
963  DPRINTF(("didn't find it and wasn't asked to create it\n"));
964  error = ENOENT;
965  goto done2;
966  }
967 
968 found:
969  td->td_retval[0] = IXSEQ_TO_IPCID(semid, sema[semid].u.sem_perm);
970 done2:
971  mtx_unlock(&sem_mtx);
972  return (error);
973 }
974 
975 #ifndef _SYS_SYSPROTO_H_
976 struct semop_args {
977  int semid;
978  struct sembuf *sops;
979  size_t nsops;
980 };
981 #endif
982 int
983 sys_semop(struct thread *td, struct semop_args *uap)
984 {
985 #define SMALL_SOPS 8
986  struct sembuf small_sops[SMALL_SOPS];
987  int semid = uap->semid;
988  size_t nsops = uap->nsops;
989  struct sembuf *sops;
990  struct semid_kernel *semakptr;
991  struct sembuf *sopptr = 0;
992  struct sem *semptr = 0;
993  struct sem_undo *suptr;
994  struct mtx *sema_mtxp;
995  size_t i, j, k;
996  int error;
997  int do_wakeup, do_undos;
998  unsigned short seq;
999 
1000 #ifdef SEM_DEBUG
1001  sops = NULL;
1002 #endif
1003  DPRINTF(("call to semop(%d, %p, %u)\n", semid, sops, nsops));
1004 
1005  if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
1006  return (ENOSYS);
1007 
1008  semid = IPCID_TO_IX(semid); /* Convert back to zero origin */
1009 
1010  if (semid < 0 || semid >= seminfo.semmni)
1011  return (EINVAL);
1012 
1013  /* Allocate memory for sem_ops */
1014  if (nsops <= SMALL_SOPS)
1015  sops = small_sops;
1016  else if (nsops > seminfo.semopm) {
1017  DPRINTF(("too many sops (max=%d, nsops=%d)\n", seminfo.semopm,
1018  nsops));
1019  return (E2BIG);
1020  } else {
1021 #ifdef RACCT
1022  PROC_LOCK(td->td_proc);
1023  if (nsops > racct_get_available(td->td_proc, RACCT_NSEMOP)) {
1024  PROC_UNLOCK(td->td_proc);
1025  return (E2BIG);
1026  }
1027  PROC_UNLOCK(td->td_proc);
1028 #endif
1029 
1030  sops = malloc(nsops * sizeof(*sops), M_TEMP, M_WAITOK);
1031  }
1032  if ((error = copyin(uap->sops, sops, nsops * sizeof(sops[0]))) != 0) {
1033  DPRINTF(("error = %d from copyin(%p, %p, %d)\n", error,
1034  uap->sops, sops, nsops * sizeof(sops[0])));
1035  if (sops != small_sops)
1036  free(sops, M_SEM);
1037  return (error);
1038  }
1039 
1040  semakptr = &sema[semid];
1041  sema_mtxp = &sema_mtx[semid];
1042  mtx_lock(sema_mtxp);
1043  if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0) {
1044  error = EINVAL;
1045  goto done2;
1046  }
1047  seq = semakptr->u.sem_perm.seq;
1048  if (seq != IPCID_TO_SEQ(uap->semid)) {
1049  error = EINVAL;
1050  goto done2;
1051  }
1052  /*
1053  * Initial pass thru sops to see what permissions are needed.
1054  * Also perform any checks that don't need repeating on each
1055  * attempt to satisfy the request vector.
1056  */
1057  j = 0; /* permission needed */
1058  do_undos = 0;
1059  for (i = 0; i < nsops; i++) {
1060  sopptr = &sops[i];
1061  if (sopptr->sem_num >= semakptr->u.sem_nsems) {
1062  error = EFBIG;
1063  goto done2;
1064  }
1065  if (sopptr->sem_flg & SEM_UNDO && sopptr->sem_op != 0)
1066  do_undos = 1;
1067  j |= (sopptr->sem_op == 0) ? SEM_R : SEM_A;
1068  }
1069 
1070  if ((error = ipcperm(td, &semakptr->u.sem_perm, j))) {
1071  DPRINTF(("error = %d from ipaccess\n", error));
1072  goto done2;
1073  }
1074 #ifdef MAC
1075  error = mac_sysvsem_check_semop(td->td_ucred, semakptr, j);
1076  if (error != 0)
1077  goto done2;
1078 #endif
1079 
1080  /*
1081  * Loop trying to satisfy the vector of requests.
1082  * If we reach a point where we must wait, any requests already
1083  * performed are rolled back and we go to sleep until some other
1084  * process wakes us up. At this point, we start all over again.
1085  *
1086  * This ensures that from the perspective of other tasks, a set
1087  * of requests is atomic (never partially satisfied).
1088  */
1089  for (;;) {
1090  do_wakeup = 0;
1091  error = 0; /* error return if necessary */
1092 
1093  for (i = 0; i < nsops; i++) {
1094  sopptr = &sops[i];
1095  semptr = &semakptr->u.sem_base[sopptr->sem_num];
1096 
1097  DPRINTF((
1098  "semop: semakptr=%p, sem_base=%p, "
1099  "semptr=%p, sem[%d]=%d : op=%d, flag=%s\n",
1100  semakptr, semakptr->u.sem_base, semptr,
1101  sopptr->sem_num, semptr->semval, sopptr->sem_op,
1102  (sopptr->sem_flg & IPC_NOWAIT) ?
1103  "nowait" : "wait"));
1104 
1105  if (sopptr->sem_op < 0) {
1106  if (semptr->semval + sopptr->sem_op < 0) {
1107  DPRINTF(("semop: can't do it now\n"));
1108  break;
1109  } else {
1110  semptr->semval += sopptr->sem_op;
1111  if (semptr->semval == 0 &&
1112  semptr->semzcnt > 0)
1113  do_wakeup = 1;
1114  }
1115  } else if (sopptr->sem_op == 0) {
1116  if (semptr->semval != 0) {
1117  DPRINTF(("semop: not zero now\n"));
1118  break;
1119  }
1120  } else if (semptr->semval + sopptr->sem_op >
1121  seminfo.semvmx) {
1122  error = ERANGE;
1123  break;
1124  } else {
1125  if (semptr->semncnt > 0)
1126  do_wakeup = 1;
1127  semptr->semval += sopptr->sem_op;
1128  }
1129  }
1130 
1131  /*
1132  * Did we get through the entire vector?
1133  */
1134  if (i >= nsops)
1135  goto done;
1136 
1137  /*
1138  * No ... rollback anything that we've already done
1139  */
1140  DPRINTF(("semop: rollback 0 through %d\n", i-1));
1141  for (j = 0; j < i; j++)
1142  semakptr->u.sem_base[sops[j].sem_num].semval -=
1143  sops[j].sem_op;
1144 
1145  /* If we detected an error, return it */
1146  if (error != 0)
1147  goto done2;
1148 
1149  /*
1150  * If the request that we couldn't satisfy has the
1151  * NOWAIT flag set then return with EAGAIN.
1152  */
1153  if (sopptr->sem_flg & IPC_NOWAIT) {
1154  error = EAGAIN;
1155  goto done2;
1156  }
1157 
1158  if (sopptr->sem_op == 0)
1159  semptr->semzcnt++;
1160  else
1161  semptr->semncnt++;
1162 
1163  DPRINTF(("semop: good night!\n"));
1164  error = msleep(semakptr, sema_mtxp, (PZERO - 4) | PCATCH,
1165  "semwait", 0);
1166  DPRINTF(("semop: good morning (error=%d)!\n", error));
1167  /* return code is checked below, after sem[nz]cnt-- */
1168 
1169  /*
1170  * Make sure that the semaphore still exists
1171  */
1172  seq = semakptr->u.sem_perm.seq;
1173  if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0 ||
1174  seq != IPCID_TO_SEQ(uap->semid)) {
1175  error = EIDRM;
1176  goto done2;
1177  }
1178 
1179  /*
1180  * Renew the semaphore's pointer after wakeup since
1181  * during msleep sem_base may have been modified and semptr
1182  * is not valid any more
1183  */
1184  semptr = &semakptr->u.sem_base[sopptr->sem_num];
1185 
1186  /*
1187  * The semaphore is still alive. Readjust the count of
1188  * waiting processes.
1189  */
1190  if (sopptr->sem_op == 0)
1191  semptr->semzcnt--;
1192  else
1193  semptr->semncnt--;
1194 
1195  /*
1196  * Is it really morning, or was our sleep interrupted?
1197  * (Delayed check of msleep() return code because we
1198  * need to decrement sem[nz]cnt either way.)
1199  */
1200  if (error != 0) {
1201  error = EINTR;
1202  goto done2;
1203  }
1204  DPRINTF(("semop: good morning!\n"));
1205  }
1206 
1207 done:
1208  /*
1209  * Process any SEM_UNDO requests.
1210  */
1211  if (do_undos) {
1212  SEMUNDO_LOCK();
1213  suptr = NULL;
1214  for (i = 0; i < nsops; i++) {
1215  /*
1216  * We only need to deal with SEM_UNDO's for non-zero
1217  * op's.
1218  */
1219  int adjval;
1220 
1221  if ((sops[i].sem_flg & SEM_UNDO) == 0)
1222  continue;
1223  adjval = sops[i].sem_op;
1224  if (adjval == 0)
1225  continue;
1226  error = semundo_adjust(td, &suptr, semid, seq,
1227  sops[i].sem_num, -adjval);
1228  if (error == 0)
1229  continue;
1230 
1231  /*
1232  * Oh-Oh! We ran out of either sem_undo's or undo's.
1233  * Rollback the adjustments to this point and then
1234  * rollback the semaphore ups and down so we can return
1235  * with an error with all structures restored. We
1236  * rollback the undo's in the exact reverse order that
1237  * we applied them. This guarantees that we won't run
1238  * out of space as we roll things back out.
1239  */
1240  for (j = 0; j < i; j++) {
1241  k = i - j - 1;
1242  if ((sops[k].sem_flg & SEM_UNDO) == 0)
1243  continue;
1244  adjval = sops[k].sem_op;
1245  if (adjval == 0)
1246  continue;
1247  if (semundo_adjust(td, &suptr, semid, seq,
1248  sops[k].sem_num, adjval) != 0)
1249  panic("semop - can't undo undos");
1250  }
1251 
1252  for (j = 0; j < nsops; j++)
1253  semakptr->u.sem_base[sops[j].sem_num].semval -=
1254  sops[j].sem_op;
1255 
1256  DPRINTF(("error = %d from semundo_adjust\n", error));
1257  SEMUNDO_UNLOCK();
1258  goto done2;
1259  } /* loop through the sops */
1260  SEMUNDO_UNLOCK();
1261  } /* if (do_undos) */
1262 
1263  /* We're definitely done - set the sempid's and time */
1264  for (i = 0; i < nsops; i++) {
1265  sopptr = &sops[i];
1266  semptr = &semakptr->u.sem_base[sopptr->sem_num];
1267  semptr->sempid = td->td_proc->p_pid;
1268  }
1269  semakptr->u.sem_otime = time_second;
1270 
1271  /*
1272  * Do a wakeup if any semaphore was up'd whilst something was
1273  * sleeping on it.
1274  */
1275  if (do_wakeup) {
1276  DPRINTF(("semop: doing wakeup\n"));
1277  wakeup(semakptr);
1278  DPRINTF(("semop: back from wakeup\n"));
1279  }
1280  DPRINTF(("semop: done\n"));
1281  td->td_retval[0] = 0;
1282 done2:
1283  mtx_unlock(sema_mtxp);
1284  if (sops != small_sops)
1285  free(sops, M_SEM);
1286  return (error);
1287 }
1288 
1289 /*
1290  * Go through the undo structures for this process and apply the adjustments to
1291  * semaphores.
1292  */
1293 static void
1294 semexit_myhook(void *arg, struct proc *p)
1295 {
1296  struct sem_undo *suptr;
1297  struct semid_kernel *semakptr;
1298  struct mtx *sema_mtxp;
1299  int semid, semnum, adjval, ix;
1300  unsigned short seq;
1301 
1302  /*
1303  * Go through the chain of undo vectors looking for one
1304  * associated with this process.
1305  */
1306  SEMUNDO_LOCK();
1307  LIST_FOREACH(suptr, &semu_list, un_next) {
1308  if (suptr->un_proc == p)
1309  break;
1310  }
1311  if (suptr == NULL) {
1312  SEMUNDO_UNLOCK();
1313  return;
1314  }
1315  LIST_REMOVE(suptr, un_next);
1316 
1317  DPRINTF(("proc @%p has undo structure with %d entries\n", p,
1318  suptr->un_cnt));
1319 
1320  /*
1321  * If there are any active undo elements then process them.
1322  */
1323  if (suptr->un_cnt > 0) {
1324  SEMUNDO_UNLOCK();
1325  for (ix = 0; ix < suptr->un_cnt; ix++) {
1326  semid = suptr->un_ent[ix].un_id;
1327  semnum = suptr->un_ent[ix].un_num;
1328  adjval = suptr->un_ent[ix].un_adjval;
1329  seq = suptr->un_ent[ix].un_seq;
1330  semakptr = &sema[semid];
1331  sema_mtxp = &sema_mtx[semid];
1332 
1333  mtx_lock(sema_mtxp);
1334  if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0 ||
1335  (semakptr->u.sem_perm.seq != seq)) {
1336  mtx_unlock(sema_mtxp);
1337  continue;
1338  }
1339  if (semnum >= semakptr->u.sem_nsems)
1340  panic("semexit - semnum out of range");
1341 
1342  DPRINTF((
1343  "semexit: %p id=%d num=%d(adj=%d) ; sem=%d\n",
1344  suptr->un_proc, suptr->un_ent[ix].un_id,
1345  suptr->un_ent[ix].un_num,
1346  suptr->un_ent[ix].un_adjval,
1347  semakptr->u.sem_base[semnum].semval));
1348 
1349  if (adjval < 0 && semakptr->u.sem_base[semnum].semval <
1350  -adjval)
1351  semakptr->u.sem_base[semnum].semval = 0;
1352  else
1353  semakptr->u.sem_base[semnum].semval += adjval;
1354 
1355  wakeup(semakptr);
1356  DPRINTF(("semexit: back from wakeup\n"));
1357  mtx_unlock(sema_mtxp);
1358  }
1359  SEMUNDO_LOCK();
1360  }
1361 
1362  /*
1363  * Deallocate the undo vector.
1364  */
1365  DPRINTF(("removing vector\n"));
1366  suptr->un_proc = NULL;
1367  suptr->un_cnt = 0;
1368  LIST_INSERT_HEAD(&semu_free_list, suptr, un_next);
1369  SEMUNDO_UNLOCK();
1370 }
1371 
1372 static int
1373 sysctl_sema(SYSCTL_HANDLER_ARGS)
1374 {
1375 
1376  return (SYSCTL_OUT(req, sema,
1377  sizeof(struct semid_kernel) * seminfo.semmni));
1378 }
1379 
1380 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
1381  defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
1382 
1383 /* XXX casting to (sy_call_t *) is bogus, as usual. */
1384 static sy_call_t *semcalls[] = {
1385  (sy_call_t *)freebsd7___semctl, (sy_call_t *)sys_semget,
1386  (sy_call_t *)sys_semop
1387 };
1388 
1389 /*
1390  * Entry point for all SEM calls.
1391  */
1392 int
1393 sys_semsys(td, uap)
1394  struct thread *td;
1395  /* XXX actually varargs. */
1396  struct semsys_args /* {
1397  int which;
1398  int a2;
1399  int a3;
1400  int a4;
1401  int a5;
1402  } */ *uap;
1403 {
1404  int error;
1405 
1406  if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
1407  return (ENOSYS);
1408  if (uap->which < 0 ||
1409  uap->which >= sizeof(semcalls)/sizeof(semcalls[0]))
1410  return (EINVAL);
1411  error = (*semcalls[uap->which])(td, &uap->a2);
1412  return (error);
1413 }
1414 
1415 #ifndef CP
1416 #define CP(src, dst, fld) do { (dst).fld = (src).fld; } while (0)
1417 #endif
1418 
1419 #ifndef _SYS_SYSPROTO_H_
1420 struct freebsd7___semctl_args {
1421  int semid;
1422  int semnum;
1423  int cmd;
1424  union semun_old *arg;
1425 };
1426 #endif
1427 int
1428 freebsd7___semctl(struct thread *td, struct freebsd7___semctl_args *uap)
1429 {
1430  struct semid_ds_old dsold;
1431  struct semid_ds dsbuf;
1432  union semun_old arg;
1433  union semun semun;
1434  register_t rval;
1435  int error;
1436 
1437  switch (uap->cmd) {
1438  case SEM_STAT:
1439  case IPC_SET:
1440  case IPC_STAT:
1441  case GETALL:
1442  case SETVAL:
1443  case SETALL:
1444  error = copyin(uap->arg, &arg, sizeof(arg));
1445  if (error)
1446  return (error);
1447  break;
1448  }
1449 
1450  switch (uap->cmd) {
1451  case SEM_STAT:
1452  case IPC_STAT:
1453  semun.buf = &dsbuf;
1454  break;
1455  case IPC_SET:
1456  error = copyin(arg.buf, &dsold, sizeof(dsold));
1457  if (error)
1458  return (error);
1459  ipcperm_old2new(&dsold.sem_perm, &dsbuf.sem_perm);
1460  CP(dsold, dsbuf, sem_base);
1461  CP(dsold, dsbuf, sem_nsems);
1462  CP(dsold, dsbuf, sem_otime);
1463  CP(dsold, dsbuf, sem_ctime);
1464  semun.buf = &dsbuf;
1465  break;
1466  case GETALL:
1467  case SETALL:
1468  semun.array = arg.array;
1469  break;
1470  case SETVAL:
1471  semun.val = arg.val;
1472  break;
1473  }
1474 
1475  error = kern_semctl(td, uap->semid, uap->semnum, uap->cmd, &semun,
1476  &rval);
1477  if (error)
1478  return (error);
1479 
1480  switch (uap->cmd) {
1481  case SEM_STAT:
1482  case IPC_STAT:
1483  bzero(&dsold, sizeof(dsold));
1484  ipcperm_new2old(&dsbuf.sem_perm, &dsold.sem_perm);
1485  CP(dsbuf, dsold, sem_base);
1486  CP(dsbuf, dsold, sem_nsems);
1487  CP(dsbuf, dsold, sem_otime);
1488  CP(dsbuf, dsold, sem_ctime);
1489  error = copyout(&dsold, arg.buf, sizeof(dsold));
1490  break;
1491  }
1492 
1493  if (error == 0)
1494  td->td_retval[0] = rval;
1495  return (error);
1496 }
1497 
1498 #endif /* COMPAT_FREEBSD{4,5,6,7} */
1499 
1500 #ifdef COMPAT_32BIT
1501 
1502 int
1503 compat32bit_semsys(struct thread *td, struct compat32bit_semsys_args *uap)
1504 {
1505 
1506 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
1507  defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
1508  switch (uap->which) {
1509  case 0:
1510  return (freebsd7_compat32bit_semctl(td,
1511  (struct freebsd7_compat32bit_semctl_args *)&uap->a2));
1512  default:
1513  return (sys_semsys(td, (struct semsys_args *)uap));
1514  }
1515 #else
1516  return (nosys(td, NULL));
1517 #endif
1518 }
1519 
1520 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
1521  defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
1522 int
1523 freebsd7_compat32bit_semctl(struct thread *td,
1524  struct freebsd7_compat32bit_semctl_args *uap)
1525 {
1526  struct semid_ds32_old dsbuf32;
1527  struct semid_ds dsbuf;
1528  union semun semun;
1529  union semun32 arg;
1530  register_t rval;
1531  int error;
1532 
1533  switch (uap->cmd) {
1534  case SEM_STAT:
1535  case IPC_SET:
1536  case IPC_STAT:
1537  case GETALL:
1538  case SETVAL:
1539  case SETALL:
1540  error = copyin(uap->arg, &arg, sizeof(arg));
1541  if (error)
1542  return (error);
1543  break;
1544  }
1545 
1546  switch (uap->cmd) {
1547  case SEM_STAT:
1548  case IPC_STAT:
1549  semun.buf = &dsbuf;
1550  break;
1551  case IPC_SET:
1552  error = copyin(PTRIN(arg.buf), &dsbuf32, sizeof(dsbuf32));
1553  if (error)
1554  return (error);
1555  compat32bit_ipcperm_old_in(&dsbuf32.sem_perm, &dsbuf.sem_perm);
1556  PTRIN_CP(dsbuf32, dsbuf, sem_base);
1557  CP(dsbuf32, dsbuf, sem_nsems);
1558  CP(dsbuf32, dsbuf, sem_otime);
1559  CP(dsbuf32, dsbuf, sem_ctime);
1560  semun.buf = &dsbuf;
1561  break;
1562  case GETALL:
1563  case SETALL:
1564  semun.array = PTRIN(arg.array);
1565  break;
1566  case SETVAL:
1567  semun.val = arg.val;
1568  break;
1569  }
1570 
1571  error = kern_semctl(td, uap->semid, uap->semnum, uap->cmd, &semun,
1572  &rval);
1573  if (error)
1574  return (error);
1575 
1576  switch (uap->cmd) {
1577  case SEM_STAT:
1578  case IPC_STAT:
1579  bzero(&dsbuf32, sizeof(dsbuf32));
1580  compat32bit_ipcperm_old_out(&dsbuf.sem_perm, &dsbuf32.sem_perm);
1581  PTROUT_CP(dsbuf, dsbuf32, sem_base);
1582  CP(dsbuf, dsbuf32, sem_nsems);
1583  CP(dsbuf, dsbuf32, sem_otime);
1584  CP(dsbuf, dsbuf32, sem_ctime);
1585  error = copyout(&dsbuf32, PTRIN(arg.buf), sizeof(dsbuf32));
1586  break;
1587  }
1588 
1589  if (error == 0)
1590  td->td_retval[0] = rval;
1591  return (error);
1592 }
1593 #endif
1594 
1595 int
1596 compat32bit_semctl(struct thread *td, struct compat32bit_semctl_args *uap)
1597 {
1598  struct semid_ds32 dsbuf32;
1599  struct semid_ds dsbuf;
1600  union semun semun;
1601  union semun32 arg;
1602  register_t rval;
1603  int error;
1604 
1605  switch (uap->cmd) {
1606  case SEM_STAT:
1607  case IPC_SET:
1608  case IPC_STAT:
1609  case GETALL:
1610  case SETVAL:
1611  case SETALL:
1612  error = copyin(uap->arg, &arg, sizeof(arg));
1613  if (error)
1614  return (error);
1615  break;
1616  }
1617 
1618  switch (uap->cmd) {
1619  case SEM_STAT:
1620  case IPC_STAT:
1621  semun.buf = &dsbuf;
1622  break;
1623  case IPC_SET:
1624  error = copyin(PTRIN(arg.buf), &dsbuf32, sizeof(dsbuf32));
1625  if (error)
1626  return (error);
1627  compat32bit_ipcperm_in(&dsbuf32.sem_perm, &dsbuf.sem_perm);
1628  PTRIN_CP(dsbuf32, dsbuf, sem_base);
1629  CP(dsbuf32, dsbuf, sem_nsems);
1630  CP(dsbuf32, dsbuf, sem_otime);
1631  CP(dsbuf32, dsbuf, sem_ctime);
1632  semun.buf = &dsbuf;
1633  break;
1634  case GETALL:
1635  case SETALL:
1636  semun.array = PTRIN(arg.array);
1637  break;
1638  case SETVAL:
1639  semun.val = arg.val;
1640  break;
1641  }
1642 
1643  error = kern_semctl(td, uap->semid, uap->semnum, uap->cmd, &semun,
1644  &rval);
1645  if (error)
1646  return (error);
1647 
1648  switch (uap->cmd) {
1649  case SEM_STAT:
1650  case IPC_STAT:
1651  bzero(&dsbuf32, sizeof(dsbuf32));
1652  compat32bit_ipcperm_out(&dsbuf.sem_perm, &dsbuf32.sem_perm);
1653  PTROUT_CP(dsbuf, dsbuf32, sem_base);
1654  CP(dsbuf, dsbuf32, sem_nsems);
1655  CP(dsbuf, dsbuf32, sem_otime);
1656  CP(dsbuf, dsbuf32, sem_ctime);
1657  error = copyout(&dsbuf32, PTRIN(arg.buf), sizeof(dsbuf32));
1658  break;
1659  }
1660 
1661  if (error == 0)
1662  td->td_retval[0] = rval;
1663  return (error);
1664 }
1665 
1666 #endif /* COMPAT_32BIT */
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Definition: kern_jail.c:2502
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Definition: sysv_sem.c:148
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