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/types.h>
  35 #include <sys/param.h>
  36 #include <sys/vmmeter.h>
  37 #include <sys/wait.h>
  38 #include <sys/queue.h>
  39 #include <sys/mman.h>
  40
  41 #include <err.h>
  42 #include <errno.h>
  43 #include <stdio.h>
  44 #include <stdlib.h>
  45 #include <string.h>
  46 #include <unistd.h>
  47 #include <fcntl.h>
  48 #include <time.h>
  49
  50 #include "limits.h"
  51 #include "perm.h"
  52 #include "utilsd.h"
  53
  54 #include "shmd.h"
  55 #include "sysvipc_hash.h"
  56 #include "sysvipc_sockets.h"
  57
  58 static struct   shminfo shminfo = {
  59 //      0,
  60         SHMMIN,
  61         SHMMNI,
  62         SHMSEG
  63 //      0
  64 };
  65
  66 /* Shared memory.*/
  67 static int shm_last_free, shm_committed, shmalloced;
  68 int shm_nused;
  69 static struct shmid_ds  *shmsegs;
  70
  71 /* Message queues.*/
  72 extern struct msginfo msginfo;
  73
  74 extern struct hashtable *clientshash;
  75
  76 static int
  77 create_sysv_file(struct shmget_msg *msg, size_t size,
  78                 struct shmid_ds *shmseg) {
  79         char filename[FILENAME_MAX];
  80         int fd;
  81         void *addr;
  82         int nsems;
  83         struct semid_pool *sems;
  84         struct msqid_pool *msgq;
  85         key_t key = msg->key;
  86         int i;
  87
  88         errno = 0;
  89
  90         switch(msg->type) {
  91                 case SHMGET:
  92                         sprintf(filename, "%s/%s_%ld", DIRPATH, SHM_NAME, key);
  93                         break;
  94                 case SEMGET:
  95                         sprintf(filename, "%s/%s_%ld", DIRPATH, SEM_NAME, key);
  96                         break;
  97                 case MSGGET:
  98                         sprintf(filename, "%s/%s_%ld", DIRPATH, MSG_NAME, key);
  99                         break;
 100                 case UNDOGET:
 101                         sprintf(filename, "%s/%s_%ld", DIRPATH, UNDO_NAME, key);
 102                         break;
 103                 default:
 104                         return (-EINVAL);
 105         }
 106
 107         fd = open(filename, O_RDWR | O_CREAT, 0666);
 108         if (fd < 0) {
 109                 sysvd_print_err("create sysv file: open\n");
 110                 goto out;
 111         }
 112
 113         ftruncate(fd, size);
 114
 115         switch(msg->type) {
 116                 case SEMGET:
 117                         /* Map the semaphore to initialize it. */
 118                         addr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
 119                         //TODO modify 0 for more sems on a page
 120                         if (!addr) {
 121                                 sysvd_print_err("create sysv file: mmap");
 122                                 goto error;
 123                         }
 124
 125                         /* There is no need for any lock because all clients
 126                          * that try to access this segment are blocked until
 127                          * it becames ~SHMSEG_REMOVED. */
 128                         sems = (struct semid_pool*)addr;
 129                         nsems = (msg->size - sizeof(struct semid_pool)) /
 130                                 sizeof(struct sem);
 131                         sysvd_print("alocate %d sems\n", nsems);
 132
 133                         /* Init lock. */
 134 #ifdef SYSV_RWLOCK
 135                         sysv_rwlock_init(&sems->rwlock);
 136 #else
 137                         sysv_mutex_init(&sems->mutex);
 138 #endif
 139                         /* Credentials are kept in shmid_ds structure. */
 140                         sems->ds.sem_perm.seq = shmseg->shm_perm.seq;
 141                         sems->ds.sem_nsems = nsems;
 142                         sems->ds.sem_otime = 0;
 143                         //sems->ds.sem_ctime = time(NULL);
 144                         //semtot += nsems;
 145                         sems->gen = 0;;
 146
 147                         /* Initialize each sem. */
 148                         memset(sems->ds.sem_base, 0, nsems + sizeof(struct sem));
 149
 150 #ifdef SYSV_SEMS
 151                         int l;
 152                         for (l=0; l < nsems; l++)
 153                                 sysv_mutex_init(&sems->ds.sem_base[l].sem_mutex);
 154 #endif
 155
 156                         munmap(addr, size);
 157
 158                         break;
 159                 case MSGGET:
 160                         /* Map the message queue to initialize it. */
 161                         addr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
 162                         if (!addr) {
 163                                 sysvd_print_err("create sysv file: mmap");
 164                                 goto error;
 165                         }
 166
 167                         /* There is no need for any lock because all clients
 168                          * that try to access this segment are blocked until
 169                          * it becames ~SHMSEG_REMOVED. */
 170                         msgq = (struct msqid_pool*)addr; //TODO
 171                         /*sysvd_print("Attention!!! : %ld %ld %ld %ld\n",
 172                                         sizeof(struct msqid_pool),
 173                                         sizeof(msgq->msghdrs),
 174                                         sizeof(msgq->msgmaps),
 175                                         sizeof(msgq->msgpool));*/
 176
 177                         /* Init lock. */
 178 #ifdef SYSV_RWLOCK
 179                         sysv_rwlock_init(&msgq->rwlock);
 180 #else
 181                         sysv_mutex_init(&msgq->mutex);
 182 #endif
 183                         /* In kernel implementation, this was done globally. */
 184                         for (i = 0; i < msginfo.msgseg; i++) {
 185                                 if (i > 0)
 186                                         msgq->msgmaps[i-1].next = i;
 187                                 msgq->msgmaps[i].next = -1;     /* implies entry is available */
 188                         }
 189                         msgq->free_msgmaps = 0;
 190                         msgq->nfree_msgmaps = msginfo.msgseg;
 191
 192                         for (i = 0; i < msginfo.msgtql; i++) {
 193                                 msgq->msghdrs[i].msg_type = 0;
 194                                 if (i > 0)
 195                                         msgq->msghdrs[i-1].msg_next = i;
 196                                 msgq->msghdrs[i].msg_next = -1;
 197                         }
 198                         msgq->free_msghdrs = 0;
 199
 200                         /* Credentials are kept in shmid_ds structure. */
 201                         msgq->ds.msg_perm.seq = shmseg->shm_perm.seq;
 202                         msgq->ds.first.msg_first_index = -1;
 203                         msgq->ds.last.msg_last_index = -1;
 204                         msgq->ds.msg_cbytes = 0;
 205                         msgq->ds.msg_qnum = 0;
 206                         msgq->ds.msg_qbytes = msginfo.msgmnb;
 207                         msgq->ds.msg_lspid = 0;
 208                         msgq->ds.msg_lrpid = 0;
 209                         msgq->ds.msg_stime = 0;
 210                         msgq->ds.msg_rtime = 0;
 211
 212                         munmap(addr, size);
 213
 214                         break;
 215                 default:
 216                         break;
 217         }
 218
 219         unlink(filename);
 220 out:
 221         return (fd);
 222 error:
 223         close(fd);
 224         return (-1);
 225 }
 226
 227 /* Install for the client the file corresponding to fd. */
 228 static int
 229 install_fd_client(pid_t pid, int fd) {
 230         int ret;
 231         struct client *cl = _hash_lookup(clientshash, pid);
 232         if (!cl) {
 233                 sysvd_print_err("no client entry for pid = %d\n", pid);
 234                 return (-1);
 235         }
 236
 237         ret = send_fd(cl->sock, fd);
 238         if (ret < 0) {
 239                 sysvd_print_err("can not send fd to client %d\n", pid);
 240                 return (-1);
 241         }
 242
 243         return (0);
 244 }
 245
 246 static int
 247 shm_find_segment_by_key(key_t key)
 248 {
 249         int i;
 250
 251         for (i = 0; i < shmalloced; i++) {
 252                 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) &&
 253                                 shmsegs[i].shm_perm.key == key)
 254                         return (i);
 255         }
 256         return (-1);
 257 }
 258
 259 static struct shmid_ds *
 260 shm_find_segment_by_shmid(int shmid)
 261 {
 262         int segnum;
 263         struct shmid_ds *shmseg;
 264
 265         segnum = IPCID_TO_IX(shmid);
 266         if (segnum < 0 || segnum >= shmalloced) {
 267                 sysvd_print_err("segnum out of range\n");
 268                 return (NULL);
 269         }
 270
 271         shmseg = &shmsegs[segnum];
 272         if ((shmseg->shm_perm.mode & (SHMSEG_ALLOCATED | SHMSEG_REMOVED))
 273                         != SHMSEG_ALLOCATED ||
 274                         shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid)) {
 275                 sysvd_print("segment most probably removed\n");
 276                 return (NULL);
 277         }
 278         return (shmseg);
 279 }
 280
 281 /* Remove a shared memory segment. */
 282 static void
 283 shm_deallocate_segment(int segnum)
 284 {
 285         size_t size;
 286         struct shmid_ds *shmseg = &shmsegs[segnum];
 287         struct shm_handle *internal =
 288                 (struct shm_handle *)shmseg->shm_internal;
 289 //      int nsems;
 290
 291         sysvd_print("deallocate segment %d\n", segnum);
 292
 293         size = round_page(shmseg->shm_segsz);
 294
 295 #if 0
 296         if (internal->type == SEMGET) {
 297                         nsems = (shmseg->shm_segsz - sizeof(struct semid_pool)) /
 298                                 sizeof(struct sem);
 299                         semtot -= nsems;
 300                         sysvd_print("freed %d sems\n", nsems);
 301         }
 302 #endif
 303
 304         /* Close the corresponding file. */
 305         close(internal->fd);
 306
 307         /* Free other resources. */
 308         free(shmseg->shm_internal);
 309         shmseg->shm_internal = NULL;
 310         shm_committed -= btoc(size);
 311         shm_nused--;
 312
 313         shmseg->shm_perm.mode = SHMSEG_FREE;
 314 }
 315
 316 static void *map_seg(int);
 317 static int munmap_seg(int, void *);
 318
 319 /* In sem and msg case notify the other processes that use it. */
 320 static void
 321 mark_segment_removed(int shmid, int type) {
 322         struct semid_pool *semaptr;
 323         struct msqid_pool *msgq;
 324
 325         switch (type) {
 326                 case SEMGET:
 327                         semaptr = (struct semid_pool *)map_seg(shmid);
 328 #ifdef SYSV_RWLOCK
 329                         sysv_rwlock_wrlock(&semaptr->rwlock);
 330 #else
 331                         sysv_mutex_lock(&semaptr->mutex);
 332 #endif
 333                         semaptr->gen = -1;
 334
 335                         /* It is not necessary to wake waiting threads because
 336                          * if the group of semaphores is acquired by a thread,
 337                          * the smaptr lock is held, so it is impossible to
 338                          * reach this point.
 339                          */
 340 #ifdef SYSV_RWLOCK
 341                         sysv_rwlock_unlock(&semaptr->rwlock);
 342 #else
 343                         sysv_mutex_unlock(&semaptr->mutex);
 344 #endif
 345                         munmap_seg(shmid, semaptr);
 346                         break;
 347                 case MSGGET :
 348                         msgq = (struct msqid_pool*)map_seg(shmid);
 349 #ifdef SYSV_RWLOCK
 350                         sysv_rwlock_wrlock(&msgq->rwlock);
 351 #else
 352                         sysv_mutex_lock(&msgq->mutex);
 353 #endif
 354                         msgq->gen = -1;
 355
 356 #ifdef SYSV_RWLOCK
 357                         sysv_rwlock_unlock(&msgq->rwlock);
 358 #else
 359                         sysv_mutex_unlock(&msgq->mutex);
 360 #endif
 361                         munmap_seg(shmid, msgq);
 362                         break;
 363                 default:
 364                         break;
 365         }
 366 }
 367
 368 /* Get the id of an existing shared memory segment. */
 369 static int
 370 shmget_existing(struct shmget_msg *shmget_msg, int mode,
 371                 int segnum, struct cmsgcred *cred)
 372 {
 373         struct shmid_ds *shmseg;
 374         int error;
 375
 376         shmseg = &shmsegs[segnum];
 377         if (shmseg->shm_perm.mode & SHMSEG_REMOVED) {
 378                 /*
 379                  * This segment is in the process of being allocated.  Wait
 380                  * until it's done, and look the key up again (in case the
 381                  * allocation failed or it was freed).
 382                  */
 383                 //TODO Maybe it will be necessary if the daemon is multithreading
 384                 /*shmseg->shm_perm.mode |= SHMSEG_WANTED;
 385                   error = tsleep((caddr_t)shmseg, PCATCH, "shmget", 0);
 386                   if (error)
 387                   return error;
 388                   return EAGAIN;*/
 389         }
 390         if ((shmget_msg->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
 391                 return (-EEXIST);
 392         error = ipcperm(cred, &shmseg->shm_perm, mode);
 393         if (error)
 394                 return (-error);
 395         if (shmget_msg->size && (shmget_msg->size > shmseg->shm_segsz))
 396                 return (-EINVAL);
 397         return (IXSEQ_TO_IPCID(segnum, shmseg->shm_perm));
 398 }
 399
 400 /* Create a shared memory segment and return the id. */
 401 static int
 402 shmget_allocate_segment(pid_t pid, struct shmget_msg *shmget_msg,
 403                 int mode, struct cmsgcred *cred)
 404 {
 405         int i, segnum, shmid;
 406         size_t size;
 407         struct shmid_ds *shmseg;
 408         struct shm_handle *handle;
 409 #if 0
 410         /* It is possible after a process calls exec().
 411          * We don't create another segment but return the old one
 412          * with all information.
 413          * This segment is destroyed only when process dies.
 414          * */
 415         if (shmget_msg->type == UNDOGET) {
 416                 struct client *cl= _hash_lookup(clientshash, pid);
 417                 if (cl->undoid != -1)
 418                         return cl->undoid;
 419         }
 420 #endif
 421         if ((long)shmget_msg->size < shminfo.shmmin)
 422                         //|| (long)shmget_msg->size > shminfo.shmmax)
 423                         /* There is no need to check the max limit,
 424                          * the operating system do this for us.
 425                          */
 426                 return (-EINVAL);
 427         if (shm_nused >= shminfo.shmmni) /* any shmids left? */
 428                 return (-ENOSPC);
 429
 430         /* Compute the size of the segment. */
 431         size = round_page(shmget_msg->size);
 432
 433         /* Find a free entry in the shmsegs vector. */
 434         if (shm_last_free < 0) {
 435                 //      shmrealloc();   /* maybe expand the shmsegs[] array */
 436                 for (i = 0; i < shmalloced; i++) {
 437                         if (shmsegs[i].shm_perm.mode & SHMSEG_FREE)
 438                                 break;
 439                 }
 440                 if (i == shmalloced) {
 441                         sysvd_print("i == shmalloced\n");
 442                         return (-ENOSPC);
 443                 }
 444                 segnum = i;
 445         } else  {
 446                 segnum = shm_last_free;
 447                 shm_last_free = -1;
 448         }
 449         shmseg = &shmsegs[segnum];
 450         /*
 451          * In case we sleep in malloc(), mark the segment present but deleted
 452          * so that noone else tries to create the same key.
 453          */
 454         shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
 455         shmseg->shm_perm.key = shmget_msg->key;
 456         shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff;
 457
 458         /* Create the file for the shared memory segment. */
 459         handle = shmseg->shm_internal = malloc(sizeof(struct shm_handle));
 460         handle->type = shmget_msg->type;
 461         handle->fd = create_sysv_file(shmget_msg, size, shmseg);
 462         if (handle->fd == -1) {
 463                 free(handle);
 464                 handle = NULL;
 465                 shmseg->shm_perm.mode = SHMSEG_FREE;
 466                 shm_last_free = segnum;
 467                 errno = -ENFILE;
 468                 return (-1);
 469         }
 470
 471         LIST_INIT(&handle->attached_list);
 472
 473         if (handle->fd < 0) {
 474                 free(shmseg->shm_internal);
 475                 shmseg->shm_internal = NULL;
 476                 shm_last_free = segnum;
 477                 shmseg->shm_perm.mode = SHMSEG_FREE;
 478                 return (-errno);
 479         }
 480
 481         /* Get the id. */
 482         shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
 483
 484         shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cmcred_euid;
 485         shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cmcred_gid;
 486         shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) |
 487                 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
 488
 489         shmseg->shm_cpid = pid;
 490         shmseg->shm_lpid = shmseg->shm_nattch = 0;
 491         shmseg->shm_atime = shmseg->shm_dtime = 0;
 492         shmseg->shm_ctime = time(NULL);
 493
 494         shmseg->shm_segsz = shmget_msg->size;
 495         shm_committed += btoc(size);
 496         shm_nused++;
 497
 498         if (shmseg->shm_perm.mode & SHMSEG_WANTED) {
 499                 /*
 500                  * Somebody else wanted this key while we were asleep.  Wake
 501                  * them up now.
 502                  */
 503                 shmseg->shm_perm.mode &= ~SHMSEG_WANTED;
 504                 //TODO multithreading
 505                 //wakeup((caddr_t)shmseg);
 506         }
 507         shmseg->shm_perm.mode &= ~SHMSEG_REMOVED;
 508
 509         if (shmget_msg->type == UNDOGET) {
 510                 /* The file is used by daemon when clients terminates
 511                  * and sem_undo resources must be cleaned.
 512                  */
 513                 struct client *cl= _hash_lookup(clientshash, pid);
 514                 cl->undoid = shmid;
 515         }
 516
 517         return (shmid);
 518 }
 519
 520 /* Handle a shmget() request. */
 521 int
 522 handle_shmget(pid_t pid, struct shmget_msg *shmget_msg,
 523                 struct cmsgcred *cred ) {
 524         int segnum, mode, error;
 525         struct shmid_ds *shmseg;
 526         struct shm_handle *handle;
 527
 528         //if (!jail_sysvipc_allowed && td->td_cmsgcred->cr_prison != NULL)
 529         //      return (ENOSYS);
 530         mode = shmget_msg->shmflg & ACCESSPERMS;
 531
 532         sysvd_print("ask for key = %ld\n", shmget_msg->key);
 533         shmget_msg->key = (shmget_msg->key & 0x3FFF) |
 534                 (shmget_msg->type << 30);
 535         sysvd_print("ask for key = %ld\n", shmget_msg->key);
 536
 537         if (shmget_msg->key != IPC_PRIVATE) {
 538                 //again:
 539                 segnum = shm_find_segment_by_key(shmget_msg->key);
 540                 if (segnum >= 0) {
 541                         error = shmget_existing(shmget_msg, mode, segnum, cred);
 542                         //TODO if daemon is multithreading
 543                         //if (error == EAGAIN)
 544                         //      goto again;
 545                         goto done;
 546                 }
 547                 if ((shmget_msg->shmflg & IPC_CREAT) == 0) {
 548                         error = -ENOENT;
 549                         goto done_err;
 550                 }
 551         }
 552         error = shmget_allocate_segment(pid, shmget_msg, mode, cred);
 553         sysvd_print("allocate segment = %d\n", error);
 554 done:
 555         /*
 556          * Install to th client the file corresponding to the
 557          * shared memory segment.
 558          * client_fd is the file descriptor added in the client
 559          * files table.
 560          */
 561         shmseg = shm_find_segment_by_shmid(error);
 562         if (shmseg == NULL) {
 563                 sysvd_print_err("can not find segment by shmid\n");
 564                 return (-1);
 565         }
 566
 567         handle = (struct shm_handle *)shmseg->shm_internal;
 568         if (install_fd_client(pid, handle->fd) != 0)
 569                 error = errno;
 570 done_err:
 571         return (error);
 572
 573 }
 574
 575 /* Handle a shmat() request. */
 576 int
 577 handle_shmat(pid_t pid, struct shmat_msg *shmat_msg,
 578                 struct cmsgcred *cred ) {
 579         int error;
 580         int fd;
 581         struct shmid_ds *shmseg;
 582         struct pid_attached *pidatt;
 583         struct shm_handle *handle;
 584         size_t new_size = shmat_msg->size;
 585         struct client *cl;
 586         struct id_attached *idatt;
 587
 588         /*if (!jail_sysvipc_allowed && td->td_cmsgcred->cr_prison != NULL)
 589           return (ENOSYS);
 590
 591 again:*/
 592         shmseg = shm_find_segment_by_shmid(shmat_msg->shmid);
 593         if (shmseg == NULL) {
 594                 sysvd_print_err("shmat error: segment was not found\n");
 595                 error = EINVAL;
 596                 goto done;
 597         }
 598         error = ipcperm(cred, &shmseg->shm_perm,
 599                         (shmat_msg->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
 600         if (error)
 601                 goto done;
 602
 603         handle = shmseg->shm_internal;
 604
 605         if (shmat_msg->size > shmseg->shm_segsz) {
 606                 if (handle->type != UNDOGET) {
 607                         error = EINVAL;
 608                         goto done;
 609                 }
 610
 611                 fd = ((struct shm_handle*)shmseg->shm_internal)->fd;
 612                 ftruncate(fd, round_page(new_size));
 613                 shmseg->shm_segsz = new_size;
 614         }
 615
 616         shmseg->shm_lpid = pid;
 617         shmseg->shm_atime = time(NULL);
 618
 619         if (handle->type != UNDOGET)
 620                 shmseg->shm_nattch++;
 621         else
 622                 shmseg->shm_nattch = 1; /* Only a process calls shmat and
 623                 only once. If it does it for more than once that is because
 624                 it called exec() and reinitialized the undo segment. */
 625
 626         /* Insert the pid in the segment list of attaced pids.
 627          * The list is checked in handle_shmdt so that only
 628          * attached pids can dettached from this segment.
 629          */
 630         sysvd_print("nattch = %d pid = %d\n",
 631                         shmseg->shm_nattch, pid);
 632
 633         pidatt = malloc(sizeof(*pidatt));
 634         pidatt->pid = pid;
 635         LIST_INSERT_HEAD(&handle->attached_list, pidatt, link);
 636
 637         /* Add the segment at the list of attached segments of the client.
 638          * It is used when the process finishes its execution. The daemon
 639          * walks through the list to dettach the segments.
 640          */
 641         idatt = malloc(sizeof(*idatt));
 642         idatt->shmid = shmat_msg->shmid;
 643         cl = _hash_lookup(clientshash, pid);
 644         LIST_INSERT_HEAD(&cl->ids_attached, idatt, link);
 645
 646         return (0);
 647 done:
 648         return (error);
 649 }
 650
 651 /* Handle a shmdt() request. */
 652 int
 653 handle_shmdt(pid_t pid, int shmid) {
 654         struct shmid_ds *shmseg;
 655         int segnum;
 656         struct shm_handle *handle;
 657         struct pid_attached *pidatt;
 658         struct id_attached *idatt;
 659         struct client *cl;
 660
 661         sysvd_print("shmdt pid %d shmid %d\n", pid, shmid);
 662         /*if (!jail_sysvipc_allowed && td->td_cmsgcred->cr_prison != NULL)
 663           return (ENOSYS);
 664         */
 665
 666         segnum = IPCID_TO_IX(shmid);
 667         shmseg = &shmsegs[segnum];
 668         handle = shmseg->shm_internal;
 669
 670         /* Check if pid is attached. */
 671         LIST_FOREACH(pidatt, &handle->attached_list, link)
 672                 if (pidatt->pid == pid)
 673                         break;
 674         if (!pidatt) {
 675                 sysvd_print_err("process %d is not attached to %d (1)\n",
 676                                 pid, shmid);
 677                 return (EINVAL);
 678         }
 679         LIST_REMOVE(pidatt, link);
 680
 681         /* Remove the segment from the list of attached segments of the pid.*/
 682         cl = _hash_lookup(clientshash, pid);
 683         LIST_FOREACH(idatt, &cl->ids_attached, link)
 684                 if (idatt->shmid == shmid)
 685                         break;
 686         if (!idatt) {
 687                 sysvd_print_err("process %d is not attached to %d (2)\n",
 688                                 pid, shmid);
 689                 return (EINVAL);
 690         }
 691         LIST_REMOVE(idatt, link);
 692
 693         shmseg->shm_dtime = time(NULL);
 694
 695         /* If no other process attaced remove the segment. */
 696         if ((--shmseg->shm_nattch <= 0) &&
 697                         (shmseg->shm_perm.mode & SHMSEG_REMOVED)) {
 698                 shm_deallocate_segment(segnum);
 699                 shm_last_free = segnum;
 700         }
 701
 702         return (0);
 703 }
 704
 705 /* Handle a shmctl() request. */
 706 int
 707 handle_shmctl(struct shmctl_msg *shmctl_msg,
 708                 struct cmsgcred *cred ) {
 709         int error = 0;
 710         struct shmid_ds *shmseg, *inbuf;
 711
 712         /*      if (!jail_sysvipc_allowed && td->td_cmsgcred->cr_prison != NULL)
 713                 return (ENOSYS);
 714                 */
 715         shmseg = shm_find_segment_by_shmid(shmctl_msg->shmid);
 716
 717         if (shmseg == NULL) {
 718                 error = EINVAL;
 719                 goto done;
 720         }
 721
 722         switch (shmctl_msg->cmd) {
 723                 case IPC_STAT:
 724                         sysvd_print("IPC STAT\n");
 725                         error = ipcperm(cred, &shmseg->shm_perm, IPC_R);
 726                         if (error) {
 727                                 sysvd_print("IPC_STAT not allowed\n");
 728                                 break;
 729                         }
 730                         shmctl_msg->buf = *shmseg;
 731                         break;
 732                 case IPC_SET:
 733                         sysvd_print("IPC SET\n");
 734                         error = ipcperm(cred, &shmseg->shm_perm, IPC_M);
 735                         if (error) {
 736                                 sysvd_print("IPC_SET not allowed\n");
 737                                 break;
 738                         }
 739                         inbuf = &shmctl_msg->buf;
 740
 741                         shmseg->shm_perm.uid = inbuf->shm_perm.uid;
 742                         shmseg->shm_perm.gid = inbuf->shm_perm.gid;
 743                         shmseg->shm_perm.mode =
 744                                 (shmseg->shm_perm.mode & ~ACCESSPERMS) |
 745                                 (inbuf->shm_perm.mode & ACCESSPERMS);
 746                         shmseg->shm_ctime = time(NULL);
 747                         break;
 748                 case IPC_RMID:
 749                         sysvd_print("IPC RMID shmid = %d\n",
 750                                         shmctl_msg->shmid);
 751                         error = ipcperm(cred, &shmseg->shm_perm, IPC_M);
 752                         if (error) {
 753                                 sysvd_print("IPC_RMID not allowed\n");
 754                                 break;
 755                         }
 756                         shmseg->shm_perm.key = IPC_PRIVATE;
 757                         shmseg->shm_perm.mode |= SHMSEG_REMOVED;
 758                         if (shmseg->shm_nattch <= 0) {
 759                                 shm_deallocate_segment(IPCID_TO_IX(shmctl_msg->shmid));
 760                                 shm_last_free = IPCID_TO_IX(shmctl_msg->shmid);
 761                         }
 762                         else {
 763                                 /* In sem and msg cases, other process must be
 764                                  * noticed about the removal. */
 765                                 struct shm_handle *internal =
 766                                         (struct shm_handle *)shmseg->shm_internal;
 767                                 mark_segment_removed(shmctl_msg->shmid,
 768                                                 internal->type);
 769                         }
 770                         break;
 771 #if 0
 772                 case SHM_LOCK:
 773                 case SHM_UNLOCK:
 774 #endif
 775                 default:
 776                         error = EINVAL;
 777                         break;
 778         }
 779 done:
 780         return (error);
 781
 782 }
 783
 784 /* Function used by daemon to map a sysv resource. */
 785 static void *
 786 map_seg(int shmid) {
 787         struct shmid_ds *shmseg;
 788         struct shm_handle *internal;
 789
 790         int fd;
 791         size_t size;
 792         void *addr;
 793
 794         shmseg = shm_find_segment_by_shmid(shmid);
 795         if (!shmseg) {
 796                 sysvd_print_err("map_seg error:"
 797                                 "semid %d not found\n", shmid);
 798                 return (NULL);
 799         }
 800
 801         internal = (struct shm_handle *)shmseg->shm_internal;
 802         if (!internal) {
 803                 sysvd_print_err("map_seg error: internal for"
 804                                 "semid %d not found\n", shmid);
 805                 return (NULL);
 806         }
 807
 808         fd = internal->fd;
 809
 810         size = round_page(shmseg->shm_segsz);
 811
 812         addr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
 813         if (!addr) {
 814                 sysvd_print_err("map_seg: error mmap semid = %d\n", shmid);
 815                 return (NULL);
 816         }
 817
 818         return (addr);
 819 }
 820
 821 /* Function used by daemon to munmap a sysv resource. */
 822 static int
 823 munmap_seg(int shmid, void *addr) {
 824         struct shmid_ds *shmseg;
 825         struct shm_handle *internal;
 826
 827         size_t size;
 828
 829         shmseg = shm_find_segment_by_shmid(shmid);
 830         if (!shmseg) {
 831                 sysvd_print_err("munmap_seg error:"
 832                                 "semid %d not found\n", shmid);
 833                 return (-1);
 834         }
 835
 836         internal = (struct shm_handle *)shmseg->shm_internal;
 837         if (!internal) {
 838                 sysvd_print_err("munmap_seg error: internal for"
 839                                 "semid %d not found\n", shmid);
 840                 return (-1);
 841         }
 842
 843         size = round_page(shmseg->shm_segsz);
 844         munmap(addr, size);
 845
 846         return (0);
 847 }
 848
 849 void
 850 shminit(void) {
 851         int i;
 852
 853         shmalloced = shminfo.shmmni;
 854         shmsegs = malloc(shmalloced * sizeof(shmsegs[0]));
 855         for (i = 0; i < shmalloced; i++) {
 856                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
 857                 shmsegs[i].shm_perm.seq = 0;
 858         }
 859         shm_last_free = 0;
 860         shm_nused = 0;
 861         shm_committed = 0;
 862
 863         /*
 864          * msginfo.msgssz should be a power of two for efficiency reasons.
 865          * It is also pretty silly if msginfo.msgssz is less than 8
 866          * or greater than about 256 so ...
 867          */
 868         i = 8;
 869         while (i < 1024 && i != msginfo.msgssz)
 870                 i <<= 1;
 871         if (i != msginfo.msgssz) {
 872                 sysvd_print_err("msginfo.msgssz=%d (0x%x)\n", msginfo.msgssz,
 873                     msginfo.msgssz);
 874                 sysvd_print_err("msginfo.msgssz not a small power of 2");
 875                 exit(-1);
 876         }
 877         msginfo.msgmax = msginfo.msgseg * msginfo.msgssz;
 878 }
 879
 880 /*static void
 881 shmfree(void) {
 882         free(shmsegs);
 883 }*/
 884
 885 int
 886 semexit(int undoid) {
 887         struct sem_undo *suptr;
 888         struct sem *semptr;
 889         struct shmid_ds *undoseg;
 890
 891         if (undoid < 0) {
 892                 return (-1);
 893         }
 894
 895         undoseg = shm_find_segment_by_shmid(undoid);
 896         /* The UNDO segment must be mapped by only one segment. */
 897         if (undoseg->shm_nattch != 1) {
 898                 sysvd_print_err("undo segment mapped by more"
 899                                 "than one process\n");
 900                 exit(-1);
 901         }
 902
 903         suptr = (struct sem_undo *)map_seg(undoid);
 904         if (suptr == NULL) {
 905                 sysvd_print_err("no %d undo segment found\n", undoid);
 906                 return (-1);
 907         }
 908
 909         /* No locking mechanism is required because only the
 910          * client and the daemon can access the UNDO segment.
 911          * At this moment the client is disconnected so only
 912          * the daemon can modify this segment.
 913          */
 914         while (suptr->un_cnt) {
 915                 struct semid_pool *semaptr;
 916                 int semid;
 917                 int semnum;
 918                 int adjval;
 919                 int ix;
 920
 921                 ix = suptr->un_cnt - 1;
 922                 semid = suptr->un_ent[ix].un_id;
 923                 semnum = suptr->un_ent[ix].un_num;
 924                 adjval = suptr->un_ent[ix].un_adjval;
 925
 926                 semaptr = (struct semid_pool *)map_seg(semid);
 927                 if (!semaptr) {
 928                         return (-1);
 929                 }
 930
 931                 /* Was it removed? */
 932                 if (semaptr->gen == -1 ||
 933                         semaptr->ds.sem_perm.seq != IPCID_TO_SEQ(semid) ||
 934                         (semaptr->ds.sem_perm.mode & SHMSEG_ALLOCATED) == 0) {
 935                         --suptr->un_cnt;
 936                         sysvd_print_err("semexit - semid not allocated\n");
 937                         continue;
 938                 }
 939                 if (semnum >= semaptr->ds.sem_nsems) {
 940                         --suptr->un_cnt;
 941                         sysvd_print_err("semexit - semnum out of range\n");
 942                         continue;
 943                 }
 944
 945 #ifdef SYSV_RWLOCK
 946 #ifdef SYSV_SEMS
 947                 sysv_rwlock_rdlock(&semaptr->rwlock);
 948 #else
 949                 sysv_rwlock_wrlock(&semaptr->rwlock);
 950 #endif //SYSV_SEMS
 951 #else
 952                 sysv_mutex_lock(&semaptr->mutex);
 953                 /* Nobody can remove the semaphore beteen the check and the
 954                  * lock acquisition because it must first send a IPC_RMID
 955                  * to me and I will process that after finishing this function.
 956                  */
 957 #endif //SYSV_RWLOCK
 958                 semptr = &semaptr->ds.sem_base[semnum];
 959 #ifdef SYSV_SEMS
 960                 sysv_mutex_lock(&semptr->sem_mutex);
 961 #endif
 962                 if (ix == suptr->un_cnt - 1 &&
 963                     semid == suptr->un_ent[ix].un_id &&
 964                     semnum == suptr->un_ent[ix].un_num &&
 965                     adjval == suptr->un_ent[ix].un_adjval) {
 966                         --suptr->un_cnt;
 967
 968                         if (adjval < 0) {
 969                                 if (semptr->semval < -adjval)
 970                                         semptr->semval = 0;
 971                                 else
 972                                         semptr->semval += adjval;
 973                         } else {
 974                                 semptr->semval += adjval;
 975                         }
 976                         /* TODO multithreaded daemon:
 977                          * Check again if the semaphore was removed and do
 978                          * not wake anyone if it was.*/
 979                         umtx_wakeup((int *)&semptr->semval, 0);
 980                 }
 981 #ifdef SYSV_SEMS
 982                 sysv_mutex_unlock(&semptr->sem_mutex);
 983 #endif
 984
 985 #ifdef SYSV_RWLOCK
 986                 sysv_rwlock_unlock(&semaptr->rwlock);
 987 #else
 988                 sysv_mutex_unlock(&semaptr->mutex);
 989 #endif
 990                 munmap_seg(semid, semaptr);
 991         }
 992
 993         munmap_seg(undoid, suptr);
 994         return (0);
 995 }
 996
 997 void
 998 shmexit(struct client *cl) {
 999         struct id_attached *idatt;
1000
1001         while (!LIST_EMPTY(&cl->ids_attached)) {
1002                 idatt = LIST_FIRST(&cl->ids_attached);
1003                 handle_shmdt(cl->pid, idatt->shmid);
1004         }
1005 }