uipc_shm.c revision 185533
1175164Sjhb/*- 2175164Sjhb * Copyright (c) 2006 Robert N. M. Watson 3175164Sjhb * All rights reserved. 4175164Sjhb * 5175164Sjhb * Redistribution and use in source and binary forms, with or without 6175164Sjhb * modification, are permitted provided that the following conditions 7175164Sjhb * are met: 8175164Sjhb * 1. Redistributions of source code must retain the above copyright 9175164Sjhb * notice, this list of conditions and the following disclaimer. 10175164Sjhb * 2. Redistributions in binary form must reproduce the above copyright 11175164Sjhb * notice, this list of conditions and the following disclaimer in the 12175164Sjhb * documentation and/or other materials provided with the distribution. 13175164Sjhb * 14175164Sjhb * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15175164Sjhb * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16175164Sjhb * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17175164Sjhb * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18175164Sjhb * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19175164Sjhb * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20175164Sjhb * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21175164Sjhb * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22175164Sjhb * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23175164Sjhb * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24175164Sjhb * SUCH DAMAGE. 25175164Sjhb */ 26175164Sjhb 27175164Sjhb/* 28175164Sjhb * Support for shared swap-backed anonymous memory objects via 29175164Sjhb * shm_open(2) and shm_unlink(2). While most of the implementation is 30175164Sjhb * here, vm_mmap.c contains mapping logic changes. 31175164Sjhb * 32175164Sjhb * TODO: 33175164Sjhb * 34175164Sjhb * (2) Need to export data to a userland tool via a sysctl. Should ipcs(1) 35175164Sjhb * and ipcrm(1) be expanded or should new tools to manage both POSIX 36175164Sjhb * kernel semaphores and POSIX shared memory be written? 37175164Sjhb * 38175164Sjhb * (3) Add support for this file type to fstat(1). 39175164Sjhb * 40175164Sjhb * (4) Resource limits? Does this need its own resource limits or are the 41175164Sjhb * existing limits in mmap(2) sufficient? 42175164Sjhb * 43175164Sjhb * (5) Partial page truncation. vnode_pager_setsize() will zero any parts 44175164Sjhb * of a partially mapped page as a result of ftruncate(2)/truncate(2). 45175164Sjhb * We can do the same (with the same pmap evil), but do we need to 46175164Sjhb * worry about the bits on disk if the page is swapped out or will the 47175164Sjhb * swapper zero the parts of a page that are invalid if the page is 48175164Sjhb * swapped back in for us? 49180059Sjhb * 50180059Sjhb * (6) Add MAC support in mac_biba(4) and mac_mls(4). 51180059Sjhb * 52180059Sjhb * (7) Add a MAC check_create() hook for creating new named objects. 53175164Sjhb */ 54175164Sjhb 55175164Sjhb#include <sys/cdefs.h> 56175164Sjhb__FBSDID("$FreeBSD: head/sys/kern/uipc_shm.c 185533 2008-12-01 22:33:50Z kan $"); 57175164Sjhb 58175164Sjhb#include "opt_mac.h" 59175164Sjhb 60175164Sjhb#include <sys/param.h> 61175164Sjhb#include <sys/fcntl.h> 62175164Sjhb#include <sys/file.h> 63175164Sjhb#include <sys/filedesc.h> 64175164Sjhb#include <sys/fnv_hash.h> 65175164Sjhb#include <sys/kernel.h> 66175164Sjhb#include <sys/lock.h> 67175164Sjhb#include <sys/malloc.h> 68175164Sjhb#include <sys/mman.h> 69175164Sjhb#include <sys/mutex.h> 70175164Sjhb#include <sys/proc.h> 71175164Sjhb#include <sys/refcount.h> 72175164Sjhb#include <sys/resourcevar.h> 73175164Sjhb#include <sys/stat.h> 74175164Sjhb#include <sys/sysctl.h> 75175164Sjhb#include <sys/sysproto.h> 76175164Sjhb#include <sys/systm.h> 77175164Sjhb#include <sys/sx.h> 78175164Sjhb#include <sys/time.h> 79175164Sjhb#include <sys/vnode.h> 80175164Sjhb 81175164Sjhb#include <security/mac/mac_framework.h> 82175164Sjhb 83175164Sjhb#include <vm/vm.h> 84175164Sjhb#include <vm/vm_param.h> 85175164Sjhb#include <vm/pmap.h> 86175164Sjhb#include <vm/vm_map.h> 87175164Sjhb#include <vm/vm_object.h> 88175164Sjhb#include <vm/vm_page.h> 89175164Sjhb#include <vm/vm_pager.h> 90175164Sjhb#include <vm/swap_pager.h> 91175164Sjhb 92175164Sjhbstruct shm_mapping { 93175164Sjhb char *sm_path; 94175164Sjhb Fnv32_t sm_fnv; 95175164Sjhb struct shmfd *sm_shmfd; 96175164Sjhb LIST_ENTRY(shm_mapping) sm_link; 97175164Sjhb}; 98175164Sjhb 99175164Sjhbstatic MALLOC_DEFINE(M_SHMFD, "shmfd", "shared memory file descriptor"); 100175164Sjhbstatic LIST_HEAD(, shm_mapping) *shm_dictionary; 101175164Sjhbstatic struct sx shm_dict_lock; 102175164Sjhbstatic struct mtx shm_timestamp_lock; 103175164Sjhbstatic u_long shm_hash; 104175164Sjhb 105175164Sjhb#define SHM_HASH(fnv) (&shm_dictionary[(fnv) & shm_hash]) 106175164Sjhb 107175164Sjhbstatic int shm_access(struct shmfd *shmfd, struct ucred *ucred, int flags); 108175164Sjhbstatic struct shmfd *shm_alloc(struct ucred *ucred, mode_t mode); 109175164Sjhbstatic void shm_dict_init(void *arg); 110175164Sjhbstatic void shm_drop(struct shmfd *shmfd); 111175164Sjhbstatic struct shmfd *shm_hold(struct shmfd *shmfd); 112175164Sjhbstatic void shm_insert(char *path, Fnv32_t fnv, struct shmfd *shmfd); 113175164Sjhbstatic struct shmfd *shm_lookup(char *path, Fnv32_t fnv); 114175164Sjhbstatic int shm_remove(char *path, Fnv32_t fnv, struct ucred *ucred); 115175164Sjhbstatic void shm_dotruncate(struct shmfd *shmfd, off_t length); 116175164Sjhb 117175164Sjhbstatic fo_rdwr_t shm_read; 118175164Sjhbstatic fo_rdwr_t shm_write; 119175164Sjhbstatic fo_truncate_t shm_truncate; 120175164Sjhbstatic fo_ioctl_t shm_ioctl; 121175164Sjhbstatic fo_poll_t shm_poll; 122175164Sjhbstatic fo_kqfilter_t shm_kqfilter; 123175164Sjhbstatic fo_stat_t shm_stat; 124175164Sjhbstatic fo_close_t shm_close; 125175164Sjhb 126175164Sjhb/* File descriptor operations. */ 127175164Sjhbstatic struct fileops shm_ops = { 128175164Sjhb .fo_read = shm_read, 129175164Sjhb .fo_write = shm_write, 130175164Sjhb .fo_truncate = shm_truncate, 131175164Sjhb .fo_ioctl = shm_ioctl, 132175164Sjhb .fo_poll = shm_poll, 133175164Sjhb .fo_kqfilter = shm_kqfilter, 134175164Sjhb .fo_stat = shm_stat, 135175164Sjhb .fo_close = shm_close, 136175164Sjhb .fo_flags = DFLAG_PASSABLE 137175164Sjhb}; 138175164Sjhb 139175164SjhbFEATURE(posix_shm, "POSIX shared memory"); 140175164Sjhb 141175164Sjhbstatic int 142175164Sjhbshm_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 143175164Sjhb int flags, struct thread *td) 144175164Sjhb{ 145175164Sjhb 146175164Sjhb return (EOPNOTSUPP); 147175164Sjhb} 148175164Sjhb 149175164Sjhbstatic int 150175164Sjhbshm_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 151175164Sjhb int flags, struct thread *td) 152175164Sjhb{ 153175164Sjhb 154175164Sjhb return (EOPNOTSUPP); 155175164Sjhb} 156175164Sjhb 157175164Sjhbstatic int 158175164Sjhbshm_truncate(struct file *fp, off_t length, struct ucred *active_cred, 159175164Sjhb struct thread *td) 160175164Sjhb{ 161175164Sjhb struct shmfd *shmfd; 162175164Sjhb#ifdef MAC 163175164Sjhb int error; 164175164Sjhb#endif 165175164Sjhb 166175164Sjhb shmfd = fp->f_data; 167175164Sjhb#ifdef MAC 168175164Sjhb error = mac_posixshm_check_truncate(active_cred, fp->f_cred, shmfd); 169175164Sjhb if (error) 170175164Sjhb return (error); 171175164Sjhb#endif 172175164Sjhb shm_dotruncate(shmfd, length); 173175164Sjhb return (0); 174175164Sjhb} 175175164Sjhb 176175164Sjhbstatic int 177175164Sjhbshm_ioctl(struct file *fp, u_long com, void *data, 178175164Sjhb struct ucred *active_cred, struct thread *td) 179175164Sjhb{ 180175164Sjhb 181175164Sjhb return (EOPNOTSUPP); 182175164Sjhb} 183175164Sjhb 184175164Sjhbstatic int 185175164Sjhbshm_poll(struct file *fp, int events, struct ucred *active_cred, 186175164Sjhb struct thread *td) 187175164Sjhb{ 188175164Sjhb 189175164Sjhb return (EOPNOTSUPP); 190175164Sjhb} 191175164Sjhb 192175164Sjhbstatic int 193175164Sjhbshm_kqfilter(struct file *fp, struct knote *kn) 194175164Sjhb{ 195175164Sjhb 196175164Sjhb return (EOPNOTSUPP); 197175164Sjhb} 198175164Sjhb 199175164Sjhbstatic int 200175164Sjhbshm_stat(struct file *fp, struct stat *sb, struct ucred *active_cred, 201175164Sjhb struct thread *td) 202175164Sjhb{ 203175164Sjhb struct shmfd *shmfd; 204175164Sjhb#ifdef MAC 205175164Sjhb int error; 206175164Sjhb#endif 207175164Sjhb 208175164Sjhb shmfd = fp->f_data; 209175164Sjhb 210175164Sjhb#ifdef MAC 211175164Sjhb error = mac_posixshm_check_stat(active_cred, fp->f_cred, shmfd); 212175164Sjhb if (error) 213175164Sjhb return (error); 214175164Sjhb#endif 215175164Sjhb 216175164Sjhb /* 217175164Sjhb * Attempt to return sanish values for fstat() on a memory file 218175164Sjhb * descriptor. 219175164Sjhb */ 220175164Sjhb bzero(sb, sizeof(*sb)); 221175164Sjhb sb->st_mode = S_IFREG | shmfd->shm_mode; /* XXX */ 222175164Sjhb sb->st_blksize = PAGE_SIZE; 223175164Sjhb sb->st_size = shmfd->shm_size; 224175164Sjhb sb->st_blocks = (sb->st_size + sb->st_blksize - 1) / sb->st_blksize; 225175164Sjhb sb->st_atimespec = shmfd->shm_atime; 226175164Sjhb sb->st_ctimespec = shmfd->shm_ctime; 227175164Sjhb sb->st_mtimespec = shmfd->shm_mtime; 228175164Sjhb sb->st_birthtimespec = shmfd->shm_birthtime; 229175164Sjhb sb->st_uid = shmfd->shm_uid; 230175164Sjhb sb->st_gid = shmfd->shm_gid; 231175164Sjhb 232175164Sjhb return (0); 233175164Sjhb} 234175164Sjhb 235175164Sjhbstatic int 236175164Sjhbshm_close(struct file *fp, struct thread *td) 237175164Sjhb{ 238175164Sjhb struct shmfd *shmfd; 239175164Sjhb 240175164Sjhb shmfd = fp->f_data; 241175164Sjhb fp->f_data = NULL; 242175164Sjhb shm_drop(shmfd); 243175164Sjhb 244175164Sjhb return (0); 245175164Sjhb} 246175164Sjhb 247175164Sjhbstatic void 248175164Sjhbshm_dotruncate(struct shmfd *shmfd, off_t length) 249175164Sjhb{ 250175164Sjhb vm_object_t object; 251175164Sjhb vm_page_t m; 252175164Sjhb vm_pindex_t nobjsize; 253175164Sjhb 254175164Sjhb object = shmfd->shm_object; 255175164Sjhb VM_OBJECT_LOCK(object); 256175164Sjhb if (length == shmfd->shm_size) { 257175164Sjhb VM_OBJECT_UNLOCK(object); 258175164Sjhb return; 259175164Sjhb } 260175164Sjhb nobjsize = OFF_TO_IDX(length + PAGE_MASK); 261175164Sjhb 262175164Sjhb /* Are we shrinking? If so, trim the end. */ 263175164Sjhb if (length < shmfd->shm_size) { 264175164Sjhb /* Toss in memory pages. */ 265175164Sjhb if (nobjsize < object->size) 266175164Sjhb vm_object_page_remove(object, nobjsize, object->size, 267175164Sjhb FALSE); 268175164Sjhb 269175164Sjhb /* Toss pages from swap. */ 270175164Sjhb if (object->type == OBJT_SWAP) 271175164Sjhb swap_pager_freespace(object, nobjsize, 272175164Sjhb object->size - nobjsize); 273175164Sjhb 274175164Sjhb /* 275175164Sjhb * If the last page is partially mapped, then zero out 276175164Sjhb * the garbage at the end of the page. See comments 277175164Sjhb * in vnode_page_setsize() for more details. 278175164Sjhb * 279175164Sjhb * XXXJHB: This handles in memory pages, but what about 280175164Sjhb * a page swapped out to disk? 281175164Sjhb */ 282175164Sjhb if ((length & PAGE_MASK) && 283175164Sjhb (m = vm_page_lookup(object, OFF_TO_IDX(length))) != NULL && 284175164Sjhb m->valid != 0) { 285175164Sjhb int base = (int)length & PAGE_MASK; 286175164Sjhb int size = PAGE_SIZE - base; 287175164Sjhb 288175164Sjhb pmap_zero_page_area(m, base, size); 289175164Sjhb vm_page_lock_queues(); 290175164Sjhb vm_page_set_validclean(m, base, size); 291175164Sjhb if (m->dirty != 0) 292175164Sjhb m->dirty = VM_PAGE_BITS_ALL; 293175164Sjhb vm_page_unlock_queues(); 294176075Salc } else if ((length & PAGE_MASK) && 295176075Salc __predict_false(object->cache != NULL)) { 296176075Salc vm_page_cache_free(object, OFF_TO_IDX(length), 297176075Salc nobjsize); 298175164Sjhb } 299175164Sjhb } 300175164Sjhb shmfd->shm_size = length; 301175164Sjhb mtx_lock(&shm_timestamp_lock); 302175164Sjhb vfs_timestamp(&shmfd->shm_ctime); 303175164Sjhb shmfd->shm_mtime = shmfd->shm_ctime; 304175164Sjhb mtx_unlock(&shm_timestamp_lock); 305175164Sjhb object->size = nobjsize; 306175164Sjhb VM_OBJECT_UNLOCK(object); 307175164Sjhb} 308175164Sjhb 309175164Sjhb/* 310175164Sjhb * shmfd object management including creation and reference counting 311175164Sjhb * routines. 312175164Sjhb */ 313175164Sjhbstatic struct shmfd * 314175164Sjhbshm_alloc(struct ucred *ucred, mode_t mode) 315175164Sjhb{ 316175164Sjhb struct shmfd *shmfd; 317175164Sjhb 318175164Sjhb shmfd = malloc(sizeof(*shmfd), M_SHMFD, M_WAITOK | M_ZERO); 319175164Sjhb shmfd->shm_size = 0; 320175164Sjhb shmfd->shm_uid = ucred->cr_uid; 321175164Sjhb shmfd->shm_gid = ucred->cr_gid; 322175164Sjhb shmfd->shm_mode = mode; 323175164Sjhb shmfd->shm_object = vm_pager_allocate(OBJT_DEFAULT, NULL, 324175164Sjhb shmfd->shm_size, VM_PROT_DEFAULT, 0); 325175164Sjhb KASSERT(shmfd->shm_object != NULL, ("shm_create: vm_pager_allocate")); 326178181Salc VM_OBJECT_LOCK(shmfd->shm_object); 327178181Salc vm_object_clear_flag(shmfd->shm_object, OBJ_ONEMAPPING); 328178181Salc vm_object_set_flag(shmfd->shm_object, OBJ_NOSPLIT); 329178181Salc VM_OBJECT_UNLOCK(shmfd->shm_object); 330175164Sjhb vfs_timestamp(&shmfd->shm_birthtime); 331175164Sjhb shmfd->shm_atime = shmfd->shm_mtime = shmfd->shm_ctime = 332175164Sjhb shmfd->shm_birthtime; 333175164Sjhb refcount_init(&shmfd->shm_refs, 1); 334175164Sjhb#ifdef MAC 335175164Sjhb mac_posixshm_init(shmfd); 336175164Sjhb mac_posixshm_create(ucred, shmfd); 337175164Sjhb#endif 338175164Sjhb 339175164Sjhb return (shmfd); 340175164Sjhb} 341175164Sjhb 342175164Sjhbstatic struct shmfd * 343175164Sjhbshm_hold(struct shmfd *shmfd) 344175164Sjhb{ 345175164Sjhb 346175164Sjhb refcount_acquire(&shmfd->shm_refs); 347175164Sjhb return (shmfd); 348175164Sjhb} 349175164Sjhb 350175164Sjhbstatic void 351175164Sjhbshm_drop(struct shmfd *shmfd) 352175164Sjhb{ 353175164Sjhb 354175164Sjhb if (refcount_release(&shmfd->shm_refs)) { 355175164Sjhb#ifdef MAC 356175164Sjhb mac_posixshm_destroy(shmfd); 357175164Sjhb#endif 358175164Sjhb vm_object_deallocate(shmfd->shm_object); 359175164Sjhb free(shmfd, M_SHMFD); 360175164Sjhb } 361175164Sjhb} 362175164Sjhb 363175164Sjhb/* 364175164Sjhb * Determine if the credentials have sufficient permissions for a 365175164Sjhb * specified combination of FREAD and FWRITE. 366175164Sjhb */ 367175164Sjhbstatic int 368175164Sjhbshm_access(struct shmfd *shmfd, struct ucred *ucred, int flags) 369175164Sjhb{ 370184413Strasz accmode_t accmode; 371175164Sjhb 372184413Strasz accmode = 0; 373175164Sjhb if (flags & FREAD) 374184413Strasz accmode |= VREAD; 375175164Sjhb if (flags & FWRITE) 376184413Strasz accmode |= VWRITE; 377175164Sjhb return (vaccess(VREG, shmfd->shm_mode, shmfd->shm_uid, shmfd->shm_gid, 378184413Strasz accmode, ucred, NULL)); 379175164Sjhb} 380175164Sjhb 381175164Sjhb/* 382175164Sjhb * Dictionary management. We maintain an in-kernel dictionary to map 383175164Sjhb * paths to shmfd objects. We use the FNV hash on the path to store 384175164Sjhb * the mappings in a hash table. 385175164Sjhb */ 386175164Sjhbstatic void 387175164Sjhbshm_dict_init(void *arg) 388175164Sjhb{ 389175164Sjhb 390175164Sjhb mtx_init(&shm_timestamp_lock, "shm timestamps", NULL, MTX_DEF); 391175164Sjhb sx_init(&shm_dict_lock, "shm dictionary"); 392175164Sjhb shm_dictionary = hashinit(1024, M_SHMFD, &shm_hash); 393175164Sjhb} 394175164SjhbSYSINIT(shm_dict_init, SI_SUB_SYSV_SHM, SI_ORDER_ANY, shm_dict_init, NULL); 395175164Sjhb 396175164Sjhbstatic struct shmfd * 397175164Sjhbshm_lookup(char *path, Fnv32_t fnv) 398175164Sjhb{ 399175164Sjhb struct shm_mapping *map; 400175164Sjhb 401175164Sjhb LIST_FOREACH(map, SHM_HASH(fnv), sm_link) { 402175164Sjhb if (map->sm_fnv != fnv) 403175164Sjhb continue; 404175164Sjhb if (strcmp(map->sm_path, path) == 0) 405175164Sjhb return (map->sm_shmfd); 406175164Sjhb } 407175164Sjhb 408175164Sjhb return (NULL); 409175164Sjhb} 410175164Sjhb 411175164Sjhbstatic void 412175164Sjhbshm_insert(char *path, Fnv32_t fnv, struct shmfd *shmfd) 413175164Sjhb{ 414175164Sjhb struct shm_mapping *map; 415175164Sjhb 416175164Sjhb map = malloc(sizeof(struct shm_mapping), M_SHMFD, M_WAITOK); 417175164Sjhb map->sm_path = path; 418175164Sjhb map->sm_fnv = fnv; 419175164Sjhb map->sm_shmfd = shm_hold(shmfd); 420175164Sjhb LIST_INSERT_HEAD(SHM_HASH(fnv), map, sm_link); 421175164Sjhb} 422175164Sjhb 423175164Sjhbstatic int 424175164Sjhbshm_remove(char *path, Fnv32_t fnv, struct ucred *ucred) 425175164Sjhb{ 426175164Sjhb struct shm_mapping *map; 427175164Sjhb int error; 428175164Sjhb 429175164Sjhb LIST_FOREACH(map, SHM_HASH(fnv), sm_link) { 430175164Sjhb if (map->sm_fnv != fnv) 431175164Sjhb continue; 432175164Sjhb if (strcmp(map->sm_path, path) == 0) { 433175164Sjhb#ifdef MAC 434175164Sjhb error = mac_posixshm_check_unlink(ucred, map->sm_shmfd); 435175164Sjhb if (error) 436175164Sjhb return (error); 437175164Sjhb#endif 438175164Sjhb error = shm_access(map->sm_shmfd, ucred, 439175164Sjhb FREAD | FWRITE); 440175164Sjhb if (error) 441175164Sjhb return (error); 442175164Sjhb LIST_REMOVE(map, sm_link); 443175164Sjhb shm_drop(map->sm_shmfd); 444175164Sjhb free(map->sm_path, M_SHMFD); 445175164Sjhb free(map, M_SHMFD); 446175164Sjhb return (0); 447175164Sjhb } 448175164Sjhb } 449175164Sjhb 450175164Sjhb return (ENOENT); 451175164Sjhb} 452175164Sjhb 453175164Sjhb/* System calls. */ 454175164Sjhbint 455175164Sjhbshm_open(struct thread *td, struct shm_open_args *uap) 456175164Sjhb{ 457175164Sjhb struct filedesc *fdp; 458175164Sjhb struct shmfd *shmfd; 459175164Sjhb struct file *fp; 460175164Sjhb char *path; 461175164Sjhb Fnv32_t fnv; 462175164Sjhb mode_t cmode; 463175164Sjhb int fd, error; 464175164Sjhb 465175164Sjhb if ((uap->flags & O_ACCMODE) != O_RDONLY && 466175164Sjhb (uap->flags & O_ACCMODE) != O_RDWR) 467175164Sjhb return (EINVAL); 468175164Sjhb 469175164Sjhb if ((uap->flags & ~(O_ACCMODE | O_CREAT | O_EXCL | O_TRUNC)) != 0) 470175164Sjhb return (EINVAL); 471175164Sjhb 472175164Sjhb fdp = td->td_proc->p_fd; 473175164Sjhb cmode = (uap->mode & ~fdp->fd_cmask) & ACCESSPERMS; 474175164Sjhb 475175164Sjhb error = falloc(td, &fp, &fd); 476175164Sjhb if (error) 477175164Sjhb return (error); 478175164Sjhb 479175164Sjhb /* A SHM_ANON path pointer creates an anonymous object. */ 480175164Sjhb if (uap->path == SHM_ANON) { 481175164Sjhb /* A read-only anonymous object is pointless. */ 482175164Sjhb if ((uap->flags & O_ACCMODE) == O_RDONLY) { 483175164Sjhb fdclose(fdp, fp, fd, td); 484175164Sjhb fdrop(fp, td); 485175164Sjhb return (EINVAL); 486175164Sjhb } 487175164Sjhb shmfd = shm_alloc(td->td_ucred, cmode); 488175164Sjhb } else { 489175164Sjhb path = malloc(MAXPATHLEN, M_SHMFD, M_WAITOK); 490175164Sjhb error = copyinstr(uap->path, path, MAXPATHLEN, NULL); 491175164Sjhb 492175164Sjhb /* Require paths to start with a '/' character. */ 493175164Sjhb if (error == 0 && path[0] != '/') 494175164Sjhb error = EINVAL; 495175164Sjhb if (error) { 496175164Sjhb fdclose(fdp, fp, fd, td); 497175164Sjhb fdrop(fp, td); 498175164Sjhb free(path, M_SHMFD); 499175164Sjhb return (error); 500175164Sjhb } 501175164Sjhb 502175164Sjhb fnv = fnv_32_str(path, FNV1_32_INIT); 503175164Sjhb sx_xlock(&shm_dict_lock); 504175164Sjhb shmfd = shm_lookup(path, fnv); 505175164Sjhb if (shmfd == NULL) { 506175164Sjhb /* Object does not yet exist, create it if requested. */ 507175164Sjhb if (uap->flags & O_CREAT) { 508175164Sjhb shmfd = shm_alloc(td->td_ucred, cmode); 509175164Sjhb shm_insert(path, fnv, shmfd); 510175164Sjhb } else { 511175164Sjhb free(path, M_SHMFD); 512175164Sjhb error = ENOENT; 513175164Sjhb } 514175164Sjhb } else { 515175164Sjhb /* 516175164Sjhb * Object already exists, obtain a new 517175164Sjhb * reference if requested and permitted. 518175164Sjhb */ 519175164Sjhb free(path, M_SHMFD); 520175164Sjhb if ((uap->flags & (O_CREAT | O_EXCL)) == 521175164Sjhb (O_CREAT | O_EXCL)) 522175164Sjhb error = EEXIST; 523175164Sjhb else { 524175164Sjhb#ifdef MAC 525175164Sjhb error = mac_posixshm_check_open(td->td_ucred, 526175164Sjhb shmfd); 527175164Sjhb if (error == 0) 528175164Sjhb#endif 529175164Sjhb error = shm_access(shmfd, td->td_ucred, 530175164Sjhb FFLAGS(uap->flags & O_ACCMODE)); 531175164Sjhb } 532175164Sjhb 533175164Sjhb /* 534175164Sjhb * Truncate the file back to zero length if 535175164Sjhb * O_TRUNC was specified and the object was 536175164Sjhb * opened with read/write. 537175164Sjhb */ 538175164Sjhb if (error == 0 && 539175164Sjhb (uap->flags & (O_ACCMODE | O_TRUNC)) == 540175164Sjhb (O_RDWR | O_TRUNC)) { 541175164Sjhb#ifdef MAC 542175164Sjhb error = mac_posixshm_check_truncate( 543175164Sjhb td->td_ucred, fp->f_cred, shmfd); 544175164Sjhb if (error == 0) 545175164Sjhb#endif 546175164Sjhb shm_dotruncate(shmfd, 0); 547175164Sjhb } 548175164Sjhb if (error == 0) 549175164Sjhb shm_hold(shmfd); 550175164Sjhb } 551175164Sjhb sx_xunlock(&shm_dict_lock); 552175164Sjhb 553175164Sjhb if (error) { 554175164Sjhb fdclose(fdp, fp, fd, td); 555175164Sjhb fdrop(fp, td); 556175164Sjhb return (error); 557175164Sjhb } 558175164Sjhb } 559175164Sjhb 560175164Sjhb finit(fp, FFLAGS(uap->flags & O_ACCMODE), DTYPE_SHM, shmfd, &shm_ops); 561175164Sjhb 562175164Sjhb FILEDESC_XLOCK(fdp); 563175164Sjhb if (fdp->fd_ofiles[fd] == fp) 564175164Sjhb fdp->fd_ofileflags[fd] |= UF_EXCLOSE; 565175164Sjhb FILEDESC_XUNLOCK(fdp); 566175164Sjhb td->td_retval[0] = fd; 567175164Sjhb fdrop(fp, td); 568175164Sjhb 569175164Sjhb return (0); 570175164Sjhb} 571175164Sjhb 572175164Sjhbint 573175164Sjhbshm_unlink(struct thread *td, struct shm_unlink_args *uap) 574175164Sjhb{ 575175164Sjhb char *path; 576175164Sjhb Fnv32_t fnv; 577175164Sjhb int error; 578175164Sjhb 579175164Sjhb path = malloc(MAXPATHLEN, M_TEMP, M_WAITOK); 580175164Sjhb error = copyinstr(uap->path, path, MAXPATHLEN, NULL); 581175164Sjhb if (error) { 582175164Sjhb free(path, M_TEMP); 583175164Sjhb return (error); 584175164Sjhb } 585175164Sjhb 586175164Sjhb fnv = fnv_32_str(path, FNV1_32_INIT); 587175164Sjhb sx_xlock(&shm_dict_lock); 588175164Sjhb error = shm_remove(path, fnv, td->td_ucred); 589175164Sjhb sx_xunlock(&shm_dict_lock); 590175164Sjhb free(path, M_TEMP); 591175164Sjhb 592175164Sjhb return (error); 593175164Sjhb} 594175164Sjhb 595175164Sjhb/* 596175164Sjhb * mmap() helper to validate mmap() requests against shm object state 597175164Sjhb * and give mmap() the vm_object to use for the mapping. 598175164Sjhb */ 599175164Sjhbint 600175164Sjhbshm_mmap(struct shmfd *shmfd, vm_size_t objsize, vm_ooffset_t foff, 601175164Sjhb vm_object_t *obj) 602175164Sjhb{ 603175164Sjhb 604175164Sjhb /* 605175164Sjhb * XXXRW: This validation is probably insufficient, and subject to 606175164Sjhb * sign errors. It should be fixed. 607175164Sjhb */ 608185533Skan if (foff >= shmfd->shm_size || 609185533Skan foff + objsize > round_page(shmfd->shm_size)) 610175164Sjhb return (EINVAL); 611175164Sjhb 612175164Sjhb mtx_lock(&shm_timestamp_lock); 613175164Sjhb vfs_timestamp(&shmfd->shm_atime); 614175164Sjhb mtx_unlock(&shm_timestamp_lock); 615175164Sjhb vm_object_reference(shmfd->shm_object); 616175164Sjhb *obj = shmfd->shm_object; 617175164Sjhb return (0); 618175164Sjhb} 619