usr.sbin/sysvipcd/shmd.c

   1 /*
   2  * Copyright (c) 1994 Adam Glass and Charles Hannum.  All rights reserved.
   3  * Copyright (c) 2013 Larisa Grigore <larisagrigore@gmail.com>
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by Adam Glass and Charles
  16  *      Hannum.
  17  * 4. The names of the authors may not be used to endorse or promote products
  18  *    derived from this software without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
  21  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  22  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  23  * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  24  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  25  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  29  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 #include <sys/types.h>
  33 #include <sys/stat.h>
  34 #include <sys/param.h>
  35 #include <sys/vmmeter.h>
  36 #include <sys/wait.h>
  37 #include <sys/queue.h>
  38 #include <sys/mman.h>
  39
  40 #include <err.h>
  41 #include <errno.h>
  42 #include <stdio.h>
  43 #include <stdlib.h>
  44 #include <string.h>
  45 #include <unistd.h>
  46 #include <fcntl.h>
  47 #include <time.h>
  48
  49 #include "limits.h"
  50 #include "perm.h"
  51 #include "utilsd.h"
  52
  53 #include "shmd.h"
  54 #include "sysvipc_hash.h"
  55 #include "sysvipc_sockets.h"
  56
  57 static struct   shminfo shminfo = {
  58 //      0,
  59         SHMMIN,
  60         SHMMNI,
  61         SHMSEG
  62 //      0
  63 };
  64
  65 /* Shared memory.*/
  66 static int shm_last_free, shm_committed, shmalloced;
  67 int shm_nused;
  68 static struct shmid_ds  *shmsegs;
  69
  70 /* Message queues.*/
  71 extern struct msginfo msginfo;
  72
  73 extern struct hashtable *clientshash;
  74
  75 static int
  76 create_sysv_file(struct shmget_msg *msg, size_t size,
  77                 struct shmid_ds *shmseg) {
  78         char filename[FILENAME_MAX];
  79         int fd;
  80         void *addr;
  81         int nsems;
  82         struct semid_pool *sems;
  83         struct msqid_pool *msgq;
  84         key_t key = msg->key;
  85         int i;
  86
  87         errno = 0;
  88
  89         switch(msg->type) {
  90                 case SHMGET:
  91                         sprintf(filename, "%s/%s_%ld", DIRPATH, SHM_NAME, key);
  92                         break;
  93                 case SEMGET:
  94                         sprintf(filename, "%s/%s_%ld", DIRPATH, SEM_NAME, key);
  95                         break;
  96                 case MSGGET:
  97                         sprintf(filename, "%s/%s_%ld", DIRPATH, MSG_NAME, key);
  98                         break;
  99                 case UNDOGET:
 100                         sprintf(filename, "%s/%s_%ld", DIRPATH, UNDO_NAME, key);
 101                         break;
 102                 default:
 103                         return (-EINVAL);
 104         }
 105
 106         fd = open(filename, O_RDWR | O_CREAT, 0666);
 107         if (fd < 0) {
 108                 sysvd_print_err("create sysv file: open\n");
 109                 goto out;
 110         }
 111
 112         ftruncate(fd, size);
 113
 114         switch(msg->type) {
 115                 case SEMGET:
 116                         /* Map the semaphore to initialize it. */
 117                         addr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
 118                         //TODO modify 0 for more sems on a page
 119                         if (!addr) {
 120                                 sysvd_print_err("create sysv file: mmap");
 121                                 goto error;
 122                         }
 123
 124                         /* There is no need for any lock because all clients
 125                          * that try to access this segment are blocked until
 126                          * it becames ~SHMSEG_REMOVED. */
 127                         sems = (struct semid_pool*)addr;
 128                         nsems = (msg->size - sizeof(struct semid_pool)) /
 129                                 sizeof(struct sem);
 130                         sysvd_print("allocate %d sems\n", nsems);
 131
 132                         /* Init lock. */
 133 #ifdef SYSV_RWLOCK
 134                         sysv_rwlock_init(&sems->rwlock);
 135 #else
 136                         sysv_mutex_init(&sems->mutex);
 137 #endif
 138                         /* Credentials are kept in shmid_ds structure. */
 139                         sems->ds.sem_perm.seq = shmseg->shm_perm.seq;
 140                         sems->ds.sem_nsems = nsems;
 141                         sems->ds.sem_otime = 0;
 142                         //sems->ds.sem_ctime = time(NULL);
 143                         //semtot += nsems;
 144                         sems->gen = 0;
 145
 146                         /* Initialize each sem. */
 147                         memset(sems->ds.sem_base, 0, nsems + sizeof(struct sem));
 148
 149 #ifdef SYSV_SEMS
 150                         int l;
 151                         for (l=0; l < nsems; l++)
 152                                 sysv_mutex_init(&sems->ds.sem_base[l].sem_mutex);
 153 #endif
 154
 155                         munmap(addr, size);
 156
 157                         break;
 158                 case MSGGET:
 159                         /* Map the message queue to initialize it. */
 160                         addr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
 161                         if (!addr) {
 162                                 sysvd_print_err("create sysv file: mmap");
 163                                 goto error;
 164                         }
 165
 166                         /* There is no need for any lock because all clients
 167                          * that try to access this segment are blocked until
 168                          * it becames ~SHMSEG_REMOVED. */
 169                         msgq = (struct msqid_pool*)addr; //TODO
 170                         /*sysvd_print("Attention!!! : %ld %ld %ld %ld\n",
 171                                         sizeof(struct msqid_pool),
 172                                         sizeof(msgq->msghdrs),
 173                                         sizeof(msgq->msgmaps),
 174                                         sizeof(msgq->msgpool));*/
 175
 176                         /* Init lock. */
 177 #ifdef SYSV_RWLOCK
 178                         sysv_rwlock_init(&msgq->rwlock);
 179 #else
 180                         sysv_mutex_init(&msgq->mutex);
 181 #endif
 182                         /* In kernel implementation, this was done globally. */
 183                         for (i = 0; i < msginfo.msgseg; i++) {
 184                                 if (i > 0)
 185                                         msgq->msgmaps[i-1].next = i;
 186                                 msgq->msgmaps[i].next = -1;     /* implies entry is available */
 187                         }
 188                         msgq->free_msgmaps = 0;
 189                         msgq->nfree_msgmaps = msginfo.msgseg;
 190
 191                         for (i = 0; i < msginfo.msgtql; i++) {
 192                                 msgq->msghdrs[i].msg_type = 0;
 193                                 if (i > 0)
 194                                         msgq->msghdrs[i-1].msg_next = i;
 195                                 msgq->msghdrs[i].msg_next = -1;
 196                         }
 197                         msgq->free_msghdrs = 0;
 198
 199                         /* Credentials are kept in shmid_ds structure. */
 200                         msgq->ds.msg_perm.seq = shmseg->shm_perm.seq;
 201                         msgq->ds.first.msg_first_index = -1;
 202                         msgq->ds.last.msg_last_index = -1;
 203                         msgq->ds.msg_cbytes = 0;
 204                         msgq->ds.msg_qnum = 0;
 205                         msgq->ds.msg_qbytes = msginfo.msgmnb;
 206                         msgq->ds.msg_lspid = 0;
 207                         msgq->ds.msg_lrpid = 0;
 208                         msgq->ds.msg_stime = 0;
 209                         msgq->ds.msg_rtime = 0;
 210
 211                         munmap(addr, size);
 212
 213                         break;
 214                 default:
 215                         break;
 216         }
 217
 218         unlink(filename);
 219 out:
 220         return (fd);
 221 error:
 222         close(fd);
 223         return (-1);
 224 }
 225
 226 /* Install for the client the file corresponding to fd. */
 227 static int
 228 install_fd_client(pid_t pid, int fd) {
 229         int ret;
 230         struct client *cl = _hash_lookup(clientshash, pid);
 231         if (!cl) {
 232                 sysvd_print_err("no client entry for pid = %d\n", pid);
 233                 return (-1);
 234         }
 235
 236         ret = send_fd(cl->sock, fd);
 237         if (ret < 0) {
 238                 sysvd_print_err("can not send fd to client %d\n", pid);
 239                 return (-1);
 240         }
 241
 242         return (0);
 243 }
 244
 245 static int
 246 shm_find_segment_by_key(key_t key)
 247 {
 248         int i;
 249
 250         for (i = 0; i < shmalloced; i++) {
 251                 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) &&
 252                                 shmsegs[i].shm_perm.key == key)
 253                         return (i);
 254         }
 255         return (-1);
 256 }
 257
 258 static struct shmid_ds *
 259 shm_find_segment_by_shmid(int shmid)
 260 {
 261         int segnum;
 262         struct shmid_ds *shmseg;
 263
 264         segnum = IPCID_TO_IX(shmid);
 265         if (segnum < 0 || segnum >= shmalloced) {
 266                 sysvd_print_err("segnum out of range\n");
 267                 return (NULL);
 268         }
 269
 270         shmseg = &shmsegs[segnum];
 271         if ((shmseg->shm_perm.mode & (SHMSEG_ALLOCATED | SHMSEG_REMOVED))
 272                         != SHMSEG_ALLOCATED ||
 273                         shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid)) {
 274                 sysvd_print("segment most probably removed\n");
 275                 return (NULL);
 276         }
 277         return (shmseg);
 278 }
 279
 280 /* Remove a shared memory segment. */
 281 static void
 282 shm_deallocate_segment(int segnum)
 283 {
 284         size_t size;
 285         struct shmid_ds *shmseg = &shmsegs[segnum];
 286         struct shm_handle *internal =
 287                 (struct shm_handle *)shmseg->shm_internal;
 288 //      int nsems;
 289
 290         sysvd_print("deallocate segment %d\n", segnum);
 291
 292         size = round_page(shmseg->shm_segsz);
 293
 294 #if 0
 295         if (internal->type == SEMGET) {
 296                         nsems = (shmseg->shm_segsz - sizeof(struct semid_pool)) /
 297                                 sizeof(struct sem);
 298                         semtot -= nsems;
 299                         sysvd_print("freed %d sems\n", nsems);
 300         }
 301 #endif
 302
 303         /* Close the corresponding file. */
 304         close(internal->fd);
 305
 306         /* Free other resources. */
 307         free(shmseg->shm_internal);
 308         shmseg->shm_internal = NULL;
 309         shm_committed -= btoc(size);
 310         shm_nused--;
 311
 312         shmseg->shm_perm.mode = SHMSEG_FREE;
 313 }
 314
 315 static void *map_seg(int);
 316 static int munmap_seg(int, void *);
 317
 318 /* In sem and msg case notify the other processes that use it. */
 319 static void
 320 mark_segment_removed(int shmid, int type) {
 321         struct semid_pool *semaptr;
 322         struct msqid_pool *msgq;
 323
 324         switch (type) {
 325                 case SEMGET:
 326                         semaptr = (struct semid_pool *)map_seg(shmid);
 327 #ifdef SYSV_RWLOCK
 328                         sysv_rwlock_wrlock(&semaptr->rwlock);
 329 #else
 330                         sysv_mutex_lock(&semaptr->mutex);
 331 #endif
 332                         semaptr->gen = -1;
 333
 334                         /* It is not necessary to wake waiting threads because
 335                          * if the group of semaphores is acquired by a thread,
 336                          * the smaptr lock is held, so it is impossible to
 337                          * reach this point.
 338                          */
 339 #ifdef SYSV_RWLOCK
 340                         sysv_rwlock_unlock(&semaptr->rwlock);
 341 #else
 342                         sysv_mutex_unlock(&semaptr->mutex);
 343 #endif
 344                         munmap_seg(shmid, semaptr);
 345                         break;
 346                 case MSGGET :
 347                         msgq = (struct msqid_pool*)map_seg(shmid);
 348 #ifdef SYSV_RWLOCK
 349                         sysv_rwlock_wrlock(&msgq->rwlock);
 350 #else
 351                         sysv_mutex_lock(&msgq->mutex);
 352 #endif
 353                         msgq->gen = -1;
 354
 355 #ifdef SYSV_RWLOCK
 356                         sysv_rwlock_unlock(&msgq->rwlock);
 357 #else
 358                         sysv_mutex_unlock(&msgq->mutex);
 359 #endif
 360                         munmap_seg(shmid, msgq);
 361                         break;
 362                 default:
 363                         break;
 364         }
 365 }
 366
 367 /* Get the id of an existing shared memory segment. */
 368 static int
 369 shmget_existing(struct shmget_msg *shmget_msg, int mode,
 370                 int segnum, struct cmsgcred *cred)
 371 {
 372         struct shmid_ds *shmseg;
 373         int error;
 374
 375         shmseg = &shmsegs[segnum];
 376         if (shmseg->shm_perm.mode & SHMSEG_REMOVED) {
 377                 /*
 378                  * This segment is in the process of being allocated.  Wait
 379                  * until it's done, and look the key up again (in case the
 380                  * allocation failed or it was freed).
 381                  */
 382                 //TODO Maybe it will be necessary if the daemon is multithreading
 383                 /*shmseg->shm_perm.mode |= SHMSEG_WANTED;
 384                   error = tsleep((caddr_t)shmseg, PCATCH, "shmget", 0);
 385                   if (error)
 386                   return error;
 387                   return EAGAIN;*/
 388         }
 389         if ((shmget_msg->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
 390                 return (-EEXIST);
 391         error = ipcperm(cred, &shmseg->shm_perm, mode);
 392         if (error)
 393                 return (-error);
 394         if (shmget_msg->size && (shmget_msg->size > shmseg->shm_segsz))
 395                 return (-EINVAL);
 396         return (IXSEQ_TO_IPCID(segnum, shmseg->shm_perm));
 397 }
 398
 399 /* Create a shared memory segment and return the id. */
 400 static int
 401 shmget_allocate_segment(pid_t pid, struct shmget_msg *shmget_msg,
 402                 int mode, struct cmsgcred *cred)
 403 {
 404         int i, segnum, shmid;
 405         size_t size;
 406         struct shmid_ds *shmseg;
 407         struct shm_handle *handle;
 408 #if 0
 409         /* It is possible after a process calls exec().
 410          * We don't create another segment but return the old one
 411          * with all information.
 412          * This segment is destroyed only when process dies.
 413          * */
 414         if (shmget_msg->type == UNDOGET) {
 415                 struct client *cl= _hash_lookup(clientshash, pid);
 416                 if (cl->undoid != -1)
 417                         return cl->undoid;
 418         }
 419 #endif
 420         if ((long)shmget_msg->size < shminfo.shmmin)
 421                         //|| (long)shmget_msg->size > shminfo.shmmax)
 422                         /* There is no need to check the max limit,
 423                          * the operating system do this for us.
 424                          */
 425                 return (-EINVAL);
 426         if (shm_nused >= shminfo.shmmni) /* any shmids left? */
 427                 return (-ENOSPC);
 428
 429         /* Compute the size of the segment. */
 430         size = round_page(shmget_msg->size);
 431
 432         /* Find a free entry in the shmsegs vector. */
 433         if (shm_last_free < 0) {
 434                 //      shmrealloc();   /* maybe expand the shmsegs[] array */
 435                 for (i = 0; i < shmalloced; i++) {
 436                         if (shmsegs[i].shm_perm.mode & SHMSEG_FREE)
 437                                 break;
 438                 }
 439                 if (i == shmalloced) {
 440                         sysvd_print("i == shmalloced\n");
 441                         return (-ENOSPC);
 442                 }
 443                 segnum = i;
 444         } else  {
 445                 segnum = shm_last_free;
 446                 shm_last_free = -1;
 447         }
 448         shmseg = &shmsegs[segnum];
 449         /*
 450          * In case we sleep in malloc(), mark the segment present but deleted
 451          * so that noone else tries to create the same key.
 452          */
 453         shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
 454         shmseg->shm_perm.key = shmget_msg->key;
 455         shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff;
 456
 457         /* Create the file for the shared memory segment. */
 458         handle = shmseg->shm_internal = malloc(sizeof(struct shm_handle));
 459         handle->type = shmget_msg->type;
 460         handle->fd = create_sysv_file(shmget_msg, size, shmseg);
 461         if (handle->fd == -1) {
 462                 free(handle);
 463                 handle = NULL;
 464                 shmseg->shm_perm.mode = SHMSEG_FREE;
 465                 shm_last_free = segnum;
 466                 errno = -ENFILE;
 467                 return (-1);
 468         }
 469
 470         LIST_INIT(&handle->attached_list);
 471
 472         if (handle->fd < 0) {
 473                 free(shmseg->shm_internal);
 474                 shmseg->shm_internal = NULL;
 475                 shm_last_free = segnum;
 476                 shmseg->shm_perm.mode = SHMSEG_FREE;
 477                 return (-errno);
 478         }
 479
 480         /* Get the id. */
 481         shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
 482
 483         shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cmcred_euid;
 484         shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cmcred_gid;
 485         shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) |
 486                 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
 487
 488         shmseg->shm_cpid = pid;
 489         shmseg->shm_lpid = shmseg->shm_nattch = 0;
 490         shmseg->shm_atime = shmseg->shm_dtime = 0;
 491         shmseg->shm_ctime = time(NULL);
 492
 493         shmseg->shm_segsz = shmget_msg->size;
 494         shm_committed += btoc(size);
 495         shm_nused++;
 496
 497         if (shmseg->shm_perm.mode & SHMSEG_WANTED) {
 498                 /*
 499                  * Somebody else wanted this key while we were asleep.  Wake
 500                  * them up now.
 501                  */
 502                 shmseg->shm_perm.mode &= ~SHMSEG_WANTED;
 503                 //TODO multithreading
 504                 //wakeup((caddr_t)shmseg);
 505         }
 506         shmseg->shm_perm.mode &= ~SHMSEG_REMOVED;
 507
 508         if (shmget_msg->type == UNDOGET) {
 509                 /* The file is used by daemon when clients terminates
 510                  * and sem_undo resources must be cleaned.
 511                  */
 512                 struct client *cl= _hash_lookup(clientshash, pid);
 513                 cl->undoid = shmid;
 514         }
 515
 516         return (shmid);
 517 }
 518
 519 /* Handle a shmget() request. */
 520 int
 521 handle_shmget(pid_t pid, struct shmget_msg *shmget_msg,
 522                 struct cmsgcred *cred ) {
 523         int segnum, mode, error;
 524         struct shmid_ds *shmseg;
 525         struct shm_handle *handle;
 526
 527         //if (!jail_sysvipc_allowed && td->td_cmsgcred->cr_prison != NULL)
 528         //      return (ENOSYS);
 529         mode = shmget_msg->shmflg & ACCESSPERMS;
 530
 531         sysvd_print("ask for key = %ld\n", shmget_msg->key);
 532         shmget_msg->key = (shmget_msg->key & 0x3FFF) |
 533                 (shmget_msg->type << 30);
 534         sysvd_print("ask for key = %ld\n", shmget_msg->key);
 535
 536         if (shmget_msg->key != IPC_PRIVATE) {
 537                 //again:
 538                 segnum = shm_find_segment_by_key(shmget_msg->key);
 539                 if (segnum >= 0) {
 540                         error = shmget_existing(shmget_msg, mode, segnum, cred);
 541                         //TODO if daemon is multithreading
 542                         //if (error == EAGAIN)
 543                         //      goto again;
 544                         goto done;
 545                 }
 546                 if ((shmget_msg->shmflg & IPC_CREAT) == 0) {
 547                         error = -ENOENT;
 548                         goto done_err;
 549                 }
 550         }
 551         error = shmget_allocate_segment(pid, shmget_msg, mode, cred);
 552         sysvd_print("allocate segment = %d\n", error);
 553 done:
 554         /*
 555          * Install to th client the file corresponding to the
 556          * shared memory segment.
 557          * client_fd is the file descriptor added in the client
 558          * files table.
 559          */
 560         shmseg = shm_find_segment_by_shmid(error);
 561         if (shmseg == NULL) {
 562                 sysvd_print_err("can not find segment by shmid\n");
 563                 return (-1);
 564         }
 565
 566         handle = (struct shm_handle *)shmseg->shm_internal;
 567         if (install_fd_client(pid, handle->fd) != 0)
 568                 error = errno;
 569 done_err:
 570         return (error);
 571
 572 }
 573
 574 /* Handle a shmat() request. */
 575 int
 576 handle_shmat(pid_t pid, struct shmat_msg *shmat_msg,
 577                 struct cmsgcred *cred ) {
 578         int error;
 579         int fd;
 580         struct shmid_ds *shmseg;
 581         struct pid_attached *pidatt;
 582         struct shm_handle *handle;
 583         size_t new_size = shmat_msg->size;
 584         struct client *cl;
 585         struct id_attached *idatt;
 586
 587         /*if (!jail_sysvipc_allowed && td->td_cmsgcred->cr_prison != NULL)
 588           return (ENOSYS);
 589
 590 again:*/
 591         shmseg = shm_find_segment_by_shmid(shmat_msg->shmid);
 592         if (shmseg == NULL) {
 593                 sysvd_print_err("shmat error: segment was not found\n");
 594                 error = EINVAL;
 595                 goto done;
 596         }
 597         error = ipcperm(cred, &shmseg->shm_perm,
 598                         (shmat_msg->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
 599         if (error)
 600                 goto done;
 601
 602         handle = shmseg->shm_internal;
 603
 604         if (shmat_msg->size > shmseg->shm_segsz) {
 605                 if (handle->type != UNDOGET) {
 606                         error = EINVAL;
 607                         goto done;
 608                 }
 609
 610                 fd = ((struct shm_handle*)shmseg->shm_internal)->fd;
 611                 ftruncate(fd, round_page(new_size));
 612                 shmseg->shm_segsz = new_size;
 613         }
 614
 615         shmseg->shm_lpid = pid;
 616         shmseg->shm_atime = time(NULL);
 617
 618         if (handle->type != UNDOGET)
 619                 shmseg->shm_nattch++;
 620         else
 621                 shmseg->shm_nattch = 1; /* Only a process calls shmat and
 622                 only once. If it does it for more than once that is because
 623                 it called exec() and reinitialized the undo segment. */
 624
 625         /* Insert the pid in the segment list of attaced pids.
 626          * The list is checked in handle_shmdt so that only
 627          * attached pids can dettached from this segment.
 628          */
 629         sysvd_print("nattch = %d pid = %d\n",
 630                         shmseg->shm_nattch, pid);
 631
 632         pidatt = malloc(sizeof(*pidatt));
 633         pidatt->pid = pid;
 634         LIST_INSERT_HEAD(&handle->attached_list, pidatt, link);
 635
 636         /* Add the segment at the list of attached segments of the client.
 637          * It is used when the process finishes its execution. The daemon
 638          * walks through the list to dettach the segments.
 639          */
 640         idatt = malloc(sizeof(*idatt));
 641         idatt->shmid = shmat_msg->shmid;
 642         cl = _hash_lookup(clientshash, pid);
 643         LIST_INSERT_HEAD(&cl->ids_attached, idatt, link);
 644
 645         return (0);
 646 done:
 647         return (error);
 648 }
 649
 650 /* Handle a shmdt() request. */
 651 int
 652 handle_shmdt(pid_t pid, int shmid) {
 653         struct shmid_ds *shmseg;
 654         int segnum;
 655         struct shm_handle *handle;
 656         struct pid_attached *pidatt;
 657         struct id_attached *idatt;
 658         struct client *cl;
 659
 660         sysvd_print("shmdt pid %d shmid %d\n", pid, shmid);
 661         /*if (!jail_sysvipc_allowed && td->td_cmsgcred->cr_prison != NULL)
 662           return (ENOSYS);
 663         */
 664
 665         segnum = IPCID_TO_IX(shmid);
 666         shmseg = &shmsegs[segnum];
 667         handle = shmseg->shm_internal;
 668
 669         /* Check if pid is attached. */
 670         LIST_FOREACH(pidatt, &handle->attached_list, link)
 671                 if (pidatt->pid == pid)
 672                         break;
 673         if (!pidatt) {
 674                 sysvd_print_err("process %d is not attached to %d (1)\n",
 675                                 pid, shmid);
 676                 return (EINVAL);
 677         }
 678         LIST_REMOVE(pidatt, link);
 679
 680         /* Remove the segment from the list of attached segments of the pid.*/
 681         cl = _hash_lookup(clientshash, pid);
 682         LIST_FOREACH(idatt, &cl->ids_attached, link)
 683                 if (idatt->shmid == shmid)
 684                         break;
 685         if (!idatt) {
 686                 sysvd_print_err("process %d is not attached to %d (2)\n",
 687                                 pid, shmid);
 688                 return (EINVAL);
 689         }
 690         LIST_REMOVE(idatt, link);
 691
 692         shmseg->shm_dtime = time(NULL);
 693
 694         /* If no other process attaced remove the segment. */
 695         if ((--shmseg->shm_nattch <= 0) &&
 696                         (shmseg->shm_perm.mode & SHMSEG_REMOVED)) {
 697                 shm_deallocate_segment(segnum);
 698                 shm_last_free = segnum;
 699         }
 700
 701         return (0);
 702 }
 703
 704 /* Handle a shmctl() request. */
 705 int
 706 handle_shmctl(struct shmctl_msg *shmctl_msg,
 707                 struct cmsgcred *cred ) {
 708         int error = 0;
 709         struct shmid_ds *shmseg, *inbuf;
 710
 711         /*      if (!jail_sysvipc_allowed && td->td_cmsgcred->cr_prison != NULL)
 712                 return (ENOSYS);
 713                 */
 714         shmseg = shm_find_segment_by_shmid(shmctl_msg->shmid);
 715
 716         if (shmseg == NULL) {
 717                 error = EINVAL;
 718                 goto done;
 719         }
 720
 721         switch (shmctl_msg->cmd) {
 722                 case IPC_STAT:
 723                         sysvd_print("IPC STAT\n");
 724                         error = ipcperm(cred, &shmseg->shm_perm, IPC_R);
 725                         if (error) {
 726                                 sysvd_print("IPC_STAT not allowed\n");
 727                                 break;
 728                         }
 729                         shmctl_msg->buf = *shmseg;
 730                         break;
 731                 case IPC_SET:
 732                         sysvd_print("IPC SET\n");
 733                         error = ipcperm(cred, &shmseg->shm_perm, IPC_M);
 734                         if (error) {
 735                                 sysvd_print("IPC_SET not allowed\n");
 736                                 break;
 737                         }
 738                         inbuf = &shmctl_msg->buf;
 739
 740                         shmseg->shm_perm.uid = inbuf->shm_perm.uid;
 741                         shmseg->shm_perm.gid = inbuf->shm_perm.gid;
 742                         shmseg->shm_perm.mode =
 743                                 (shmseg->shm_perm.mode & ~ACCESSPERMS) |
 744                                 (inbuf->shm_perm.mode & ACCESSPERMS);
 745                         shmseg->shm_ctime = time(NULL);
 746                         break;
 747                 case IPC_RMID:
 748                         sysvd_print("IPC RMID shmid = %d\n",
 749                                         shmctl_msg->shmid);
 750                         error = ipcperm(cred, &shmseg->shm_perm, IPC_M);
 751                         if (error) {
 752                                 sysvd_print("IPC_RMID not allowed\n");
 753                                 break;
 754                         }
 755                         shmseg->shm_perm.key = IPC_PRIVATE;
 756                         shmseg->shm_perm.mode |= SHMSEG_REMOVED;
 757                         if (shmseg->shm_nattch <= 0) {
 758                                 shm_deallocate_segment(IPCID_TO_IX(shmctl_msg->shmid));
 759                                 shm_last_free = IPCID_TO_IX(shmctl_msg->shmid);
 760                         }
 761                         else {
 762                                 /* In sem and msg cases, other process must be
 763                                  * noticed about the removal. */
 764                                 struct shm_handle *internal =
 765                                         (struct shm_handle *)shmseg->shm_internal;
 766                                 mark_segment_removed(shmctl_msg->shmid,
 767                                                 internal->type);
 768                         }
 769                         break;
 770 #if 0
 771                 case SHM_LOCK:
 772                 case SHM_UNLOCK:
 773 #endif
 774                 default:
 775                         error = EINVAL;
 776                         break;
 777         }
 778 done:
 779         return (error);
 780
 781 }
 782
 783 /* Function used by daemon to map a sysv resource. */
 784 static void *
 785 map_seg(int shmid) {
 786         struct shmid_ds *shmseg;
 787         struct shm_handle *internal;
 788
 789         int fd;
 790         size_t size;
 791         void *addr;
 792
 793         shmseg = shm_find_segment_by_shmid(shmid);
 794         if (!shmseg) {
 795                 sysvd_print_err("map_seg error:"
 796                                 "semid %d not found\n", shmid);
 797                 return (NULL);
 798         }
 799
 800         internal = (struct shm_handle *)shmseg->shm_internal;
 801         if (!internal) {
 802                 sysvd_print_err("map_seg error: internal for"
 803                                 "semid %d not found\n", shmid);
 804                 return (NULL);
 805         }
 806
 807         fd = internal->fd;
 808
 809         size = round_page(shmseg->shm_segsz);
 810
 811         addr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
 812         if (!addr) {
 813                 sysvd_print_err("map_seg: error mmap semid = %d\n", shmid);
 814                 return (NULL);
 815         }
 816
 817         return (addr);
 818 }
 819
 820 /* Function used by daemon to munmap a sysv resource. */
 821 static int
 822 munmap_seg(int shmid, void *addr) {
 823         struct shmid_ds *shmseg;
 824         struct shm_handle *internal;
 825
 826         size_t size;
 827
 828         shmseg = shm_find_segment_by_shmid(shmid);
 829         if (!shmseg) {
 830                 sysvd_print_err("munmap_seg error:"
 831                                 "semid %d not found\n", shmid);
 832                 return (-1);
 833         }
 834
 835         internal = (struct shm_handle *)shmseg->shm_internal;
 836         if (!internal) {
 837                 sysvd_print_err("munmap_seg error: internal for"
 838                                 "semid %d not found\n", shmid);
 839                 return (-1);
 840         }
 841
 842         size = round_page(shmseg->shm_segsz);
 843         munmap(addr, size);
 844
 845         return (0);
 846 }
 847
 848 void
 849 shminit(void) {
 850         int i;
 851
 852         shmalloced = shminfo.shmmni;
 853         shmsegs = malloc(shmalloced * sizeof(shmsegs[0]));
 854         for (i = 0; i < shmalloced; i++) {
 855                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
 856                 shmsegs[i].shm_perm.seq = 0;
 857         }
 858         shm_last_free = 0;
 859         shm_nused = 0;
 860         shm_committed = 0;
 861
 862         /*
 863          * msginfo.msgssz should be a power of two for efficiency reasons.
 864          * It is also pretty silly if msginfo.msgssz is less than 8
 865          * or greater than about 256 so ...
 866          */
 867         i = 8;
 868         while (i < 1024 && i != msginfo.msgssz)
 869                 i <<= 1;
 870         if (i != msginfo.msgssz) {
 871                 sysvd_print_err("msginfo.msgssz=%d (0x%x)\n", msginfo.msgssz,
 872                     msginfo.msgssz);
 873                 sysvd_print_err("msginfo.msgssz not a small power of 2");
 874                 exit(-1);
 875         }
 876         msginfo.msgmax = msginfo.msgseg * msginfo.msgssz;
 877 }
 878
 879 /*static void
 880 shmfree(void) {
 881         free(shmsegs);
 882 }*/
 883
 884 int
 885 semexit(int undoid) {
 886         struct sem_undo *suptr;
 887         struct sem *semptr;
 888         struct shmid_ds *undoseg;
 889
 890         if (undoid < 0) {
 891                 return (-1);
 892         }
 893
 894         undoseg = shm_find_segment_by_shmid(undoid);
 895         /* The UNDO segment must be mapped by only one segment. */
 896         if (undoseg->shm_nattch != 1) {
 897                 sysvd_print_err("undo segment mapped by more"
 898                                 "than one process\n");
 899                 exit(-1);
 900         }
 901
 902         suptr = (struct sem_undo *)map_seg(undoid);
 903         if (suptr == NULL) {
 904                 sysvd_print_err("no %d undo segment found\n", undoid);
 905                 return (-1);
 906         }
 907
 908         /* No locking mechanism is required because only the
 909          * client and the daemon can access the UNDO segment.
 910          * At this moment the client is disconnected so only
 911          * the daemon can modify this segment.
 912          */
 913         while (suptr->un_cnt) {
 914                 struct semid_pool *semaptr;
 915                 int semid;
 916                 int semnum;
 917                 int adjval;
 918                 int ix;
 919
 920                 ix = suptr->un_cnt - 1;
 921                 semid = suptr->un_ent[ix].un_id;
 922                 semnum = suptr->un_ent[ix].un_num;
 923                 adjval = suptr->un_ent[ix].un_adjval;
 924
 925                 semaptr = (struct semid_pool *)map_seg(semid);
 926                 if (!semaptr) {
 927                         return (-1);
 928                 }
 929
 930                 /* Was it removed? */
 931                 if (semaptr->gen == -1 ||
 932                         semaptr->ds.sem_perm.seq != IPCID_TO_SEQ(semid) ||
 933                         (semaptr->ds.sem_perm.mode & SHMSEG_ALLOCATED) == 0) {
 934                         --suptr->un_cnt;
 935                         sysvd_print_err("semexit - semid not allocated\n");
 936                         continue;
 937                 }
 938                 if (semnum >= semaptr->ds.sem_nsems) {
 939                         --suptr->un_cnt;
 940                         sysvd_print_err("semexit - semnum out of range\n");
 941                         continue;
 942                 }
 943
 944 #ifdef SYSV_RWLOCK
 945 #ifdef SYSV_SEMS
 946                 sysv_rwlock_rdlock(&semaptr->rwlock);
 947 #else
 948                 sysv_rwlock_wrlock(&semaptr->rwlock);
 949 #endif //SYSV_SEMS
 950 #else
 951                 sysv_mutex_lock(&semaptr->mutex);
 952                 /* Nobody can remove the semaphore beteen the check and the
 953                  * lock acquisition because it must first send a IPC_RMID
 954                  * to me and I will process that after finishing this function.
 955                  */
 956 #endif //SYSV_RWLOCK
 957                 semptr = &semaptr->ds.sem_base[semnum];
 958 #ifdef SYSV_SEMS
 959                 sysv_mutex_lock(&semptr->sem_mutex);
 960 #endif
 961                 if (ix == suptr->un_cnt - 1 &&
 962                     semid == suptr->un_ent[ix].un_id &&
 963                     semnum == suptr->un_ent[ix].un_num &&
 964                     adjval == suptr->un_ent[ix].un_adjval) {
 965                         --suptr->un_cnt;
 966
 967                         if (adjval < 0) {
 968                                 if (semptr->semval < -adjval)
 969                                         semptr->semval = 0;
 970                                 else
 971                                         semptr->semval += adjval;
 972                         } else {
 973                                 semptr->semval += adjval;
 974                         }
 975                         /* TODO multithreaded daemon:
 976                          * Check again if the semaphore was removed and do
 977                          * not wake anyone if it was.*/
 978                         umtx_wakeup((int *)&semptr->semval, 0);
 979                 }
 980 #ifdef SYSV_SEMS
 981                 sysv_mutex_unlock(&semptr->sem_mutex);
 982 #endif
 983
 984 #ifdef SYSV_RWLOCK
 985                 sysv_rwlock_unlock(&semaptr->rwlock);
 986 #else
 987                 sysv_mutex_unlock(&semaptr->mutex);
 988 #endif
 989                 munmap_seg(semid, semaptr);
 990         }
 991
 992         munmap_seg(undoid, suptr);
 993         return (0);
 994 }
 995
 996 void
 997 shmexit(struct client *cl) {
 998         struct id_attached *idatt;
 999
1000         while (!LIST_EMPTY(&cl->ids_attached)) {
1001                 idatt = LIST_FIRST(&cl->ids_attached);
1002                 handle_shmdt(cl->pid, idatt->shmid);
1003         }
1004 }