uipc_shm.c revision 229821
1175164Sjhb/*- 2225344Srwatson * Copyright (c) 2006, 2011 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 * 34225344Srwatson * (1) 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 * 38225344Srwatson * (2) Add support for this file type to fstat(1). 39175164Sjhb * 40225344Srwatson * (3) Resource limits? Does this need its own resource limits or are the 41175164Sjhb * existing limits in mmap(2) sufficient? 42175164Sjhb */ 43175164Sjhb 44175164Sjhb#include <sys/cdefs.h> 45175164Sjhb__FBSDID("$FreeBSD: head/sys/kern/uipc_shm.c 229821 2012-01-08 20:09:26Z alc $"); 46175164Sjhb 47223692Sjonathan#include "opt_capsicum.h" 48223692Sjonathan 49175164Sjhb#include <sys/param.h> 50223692Sjonathan#include <sys/capability.h> 51175164Sjhb#include <sys/fcntl.h> 52175164Sjhb#include <sys/file.h> 53175164Sjhb#include <sys/filedesc.h> 54175164Sjhb#include <sys/fnv_hash.h> 55175164Sjhb#include <sys/kernel.h> 56175164Sjhb#include <sys/lock.h> 57175164Sjhb#include <sys/malloc.h> 58175164Sjhb#include <sys/mman.h> 59175164Sjhb#include <sys/mutex.h> 60224914Skib#include <sys/priv.h> 61175164Sjhb#include <sys/proc.h> 62175164Sjhb#include <sys/refcount.h> 63175164Sjhb#include <sys/resourcevar.h> 64175164Sjhb#include <sys/stat.h> 65175164Sjhb#include <sys/sysctl.h> 66175164Sjhb#include <sys/sysproto.h> 67175164Sjhb#include <sys/systm.h> 68175164Sjhb#include <sys/sx.h> 69175164Sjhb#include <sys/time.h> 70175164Sjhb#include <sys/vnode.h> 71175164Sjhb 72175164Sjhb#include <security/mac/mac_framework.h> 73175164Sjhb 74175164Sjhb#include <vm/vm.h> 75175164Sjhb#include <vm/vm_param.h> 76175164Sjhb#include <vm/pmap.h> 77228533Sjhb#include <vm/vm_extern.h> 78175164Sjhb#include <vm/vm_map.h> 79228509Sjhb#include <vm/vm_kern.h> 80175164Sjhb#include <vm/vm_object.h> 81175164Sjhb#include <vm/vm_page.h> 82229821Salc#include <vm/vm_pageout.h> 83175164Sjhb#include <vm/vm_pager.h> 84175164Sjhb#include <vm/swap_pager.h> 85175164Sjhb 86175164Sjhbstruct shm_mapping { 87175164Sjhb char *sm_path; 88175164Sjhb Fnv32_t sm_fnv; 89175164Sjhb struct shmfd *sm_shmfd; 90175164Sjhb LIST_ENTRY(shm_mapping) sm_link; 91175164Sjhb}; 92175164Sjhb 93175164Sjhbstatic MALLOC_DEFINE(M_SHMFD, "shmfd", "shared memory file descriptor"); 94175164Sjhbstatic LIST_HEAD(, shm_mapping) *shm_dictionary; 95175164Sjhbstatic struct sx shm_dict_lock; 96175164Sjhbstatic struct mtx shm_timestamp_lock; 97175164Sjhbstatic u_long shm_hash; 98175164Sjhb 99175164Sjhb#define SHM_HASH(fnv) (&shm_dictionary[(fnv) & shm_hash]) 100175164Sjhb 101175164Sjhbstatic int shm_access(struct shmfd *shmfd, struct ucred *ucred, int flags); 102175164Sjhbstatic struct shmfd *shm_alloc(struct ucred *ucred, mode_t mode); 103175164Sjhbstatic void shm_dict_init(void *arg); 104175164Sjhbstatic void shm_drop(struct shmfd *shmfd); 105175164Sjhbstatic struct shmfd *shm_hold(struct shmfd *shmfd); 106175164Sjhbstatic void shm_insert(char *path, Fnv32_t fnv, struct shmfd *shmfd); 107175164Sjhbstatic struct shmfd *shm_lookup(char *path, Fnv32_t fnv); 108175164Sjhbstatic int shm_remove(char *path, Fnv32_t fnv, struct ucred *ucred); 109194766Skibstatic int shm_dotruncate(struct shmfd *shmfd, off_t length); 110175164Sjhb 111175164Sjhbstatic fo_rdwr_t shm_read; 112175164Sjhbstatic fo_rdwr_t shm_write; 113175164Sjhbstatic fo_truncate_t shm_truncate; 114175164Sjhbstatic fo_ioctl_t shm_ioctl; 115175164Sjhbstatic fo_poll_t shm_poll; 116175164Sjhbstatic fo_kqfilter_t shm_kqfilter; 117175164Sjhbstatic fo_stat_t shm_stat; 118175164Sjhbstatic fo_close_t shm_close; 119224914Skibstatic fo_chmod_t shm_chmod; 120224914Skibstatic fo_chown_t shm_chown; 121175164Sjhb 122175164Sjhb/* File descriptor operations. */ 123175164Sjhbstatic struct fileops shm_ops = { 124175164Sjhb .fo_read = shm_read, 125175164Sjhb .fo_write = shm_write, 126175164Sjhb .fo_truncate = shm_truncate, 127175164Sjhb .fo_ioctl = shm_ioctl, 128175164Sjhb .fo_poll = shm_poll, 129175164Sjhb .fo_kqfilter = shm_kqfilter, 130175164Sjhb .fo_stat = shm_stat, 131175164Sjhb .fo_close = shm_close, 132224914Skib .fo_chmod = shm_chmod, 133224914Skib .fo_chown = shm_chown, 134175164Sjhb .fo_flags = DFLAG_PASSABLE 135175164Sjhb}; 136175164Sjhb 137175164SjhbFEATURE(posix_shm, "POSIX shared memory"); 138175164Sjhb 139175164Sjhbstatic int 140175164Sjhbshm_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 141175164Sjhb int flags, struct thread *td) 142175164Sjhb{ 143175164Sjhb 144175164Sjhb return (EOPNOTSUPP); 145175164Sjhb} 146175164Sjhb 147175164Sjhbstatic int 148175164Sjhbshm_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 149175164Sjhb int flags, struct thread *td) 150175164Sjhb{ 151175164Sjhb 152175164Sjhb return (EOPNOTSUPP); 153175164Sjhb} 154175164Sjhb 155175164Sjhbstatic int 156175164Sjhbshm_truncate(struct file *fp, off_t length, struct ucred *active_cred, 157175164Sjhb struct thread *td) 158175164Sjhb{ 159175164Sjhb struct shmfd *shmfd; 160175164Sjhb#ifdef MAC 161175164Sjhb int error; 162175164Sjhb#endif 163175164Sjhb 164175164Sjhb shmfd = fp->f_data; 165175164Sjhb#ifdef MAC 166175164Sjhb error = mac_posixshm_check_truncate(active_cred, fp->f_cred, shmfd); 167175164Sjhb if (error) 168175164Sjhb return (error); 169175164Sjhb#endif 170194766Skib return (shm_dotruncate(shmfd, length)); 171175164Sjhb} 172175164Sjhb 173175164Sjhbstatic int 174175164Sjhbshm_ioctl(struct file *fp, u_long com, void *data, 175175164Sjhb struct ucred *active_cred, struct thread *td) 176175164Sjhb{ 177175164Sjhb 178175164Sjhb return (EOPNOTSUPP); 179175164Sjhb} 180175164Sjhb 181175164Sjhbstatic int 182175164Sjhbshm_poll(struct file *fp, int events, struct ucred *active_cred, 183175164Sjhb struct thread *td) 184175164Sjhb{ 185175164Sjhb 186175164Sjhb return (EOPNOTSUPP); 187175164Sjhb} 188175164Sjhb 189175164Sjhbstatic int 190175164Sjhbshm_kqfilter(struct file *fp, struct knote *kn) 191175164Sjhb{ 192175164Sjhb 193175164Sjhb return (EOPNOTSUPP); 194175164Sjhb} 195175164Sjhb 196175164Sjhbstatic int 197175164Sjhbshm_stat(struct file *fp, struct stat *sb, struct ucred *active_cred, 198175164Sjhb struct thread *td) 199175164Sjhb{ 200175164Sjhb struct shmfd *shmfd; 201175164Sjhb#ifdef MAC 202175164Sjhb int error; 203175164Sjhb#endif 204175164Sjhb 205175164Sjhb shmfd = fp->f_data; 206175164Sjhb 207175164Sjhb#ifdef MAC 208175164Sjhb error = mac_posixshm_check_stat(active_cred, fp->f_cred, shmfd); 209175164Sjhb if (error) 210175164Sjhb return (error); 211175164Sjhb#endif 212175164Sjhb 213175164Sjhb /* 214175164Sjhb * Attempt to return sanish values for fstat() on a memory file 215175164Sjhb * descriptor. 216175164Sjhb */ 217175164Sjhb bzero(sb, sizeof(*sb)); 218175164Sjhb sb->st_blksize = PAGE_SIZE; 219175164Sjhb sb->st_size = shmfd->shm_size; 220175164Sjhb sb->st_blocks = (sb->st_size + sb->st_blksize - 1) / sb->st_blksize; 221224914Skib mtx_lock(&shm_timestamp_lock); 222205792Sed sb->st_atim = shmfd->shm_atime; 223205792Sed sb->st_ctim = shmfd->shm_ctime; 224205792Sed sb->st_mtim = shmfd->shm_mtime; 225224914Skib sb->st_birthtim = shmfd->shm_birthtime; 226224914Skib sb->st_mode = S_IFREG | shmfd->shm_mode; /* XXX */ 227175164Sjhb sb->st_uid = shmfd->shm_uid; 228175164Sjhb sb->st_gid = shmfd->shm_gid; 229224914Skib mtx_unlock(&shm_timestamp_lock); 230175164Sjhb 231175164Sjhb return (0); 232175164Sjhb} 233175164Sjhb 234175164Sjhbstatic int 235175164Sjhbshm_close(struct file *fp, struct thread *td) 236175164Sjhb{ 237175164Sjhb struct shmfd *shmfd; 238175164Sjhb 239175164Sjhb shmfd = fp->f_data; 240175164Sjhb fp->f_data = NULL; 241175164Sjhb shm_drop(shmfd); 242175164Sjhb 243175164Sjhb return (0); 244175164Sjhb} 245175164Sjhb 246194766Skibstatic int 247175164Sjhbshm_dotruncate(struct shmfd *shmfd, off_t length) 248175164Sjhb{ 249175164Sjhb vm_object_t object; 250229821Salc vm_page_t m, ma[1]; 251229821Salc vm_pindex_t idx, nobjsize; 252194766Skib vm_ooffset_t delta; 253229821Salc int base, rv; 254175164Sjhb 255175164Sjhb object = shmfd->shm_object; 256175164Sjhb VM_OBJECT_LOCK(object); 257175164Sjhb if (length == shmfd->shm_size) { 258175164Sjhb VM_OBJECT_UNLOCK(object); 259194766Skib return (0); 260175164Sjhb } 261175164Sjhb nobjsize = OFF_TO_IDX(length + PAGE_MASK); 262175164Sjhb 263175164Sjhb /* Are we shrinking? If so, trim the end. */ 264175164Sjhb if (length < shmfd->shm_size) { 265228509Sjhb /* 266228509Sjhb * Disallow any requests to shrink the size if this 267228509Sjhb * object is mapped into the kernel. 268228509Sjhb */ 269228509Sjhb if (shmfd->shm_kmappings > 0) { 270228509Sjhb VM_OBJECT_UNLOCK(object); 271228509Sjhb return (EBUSY); 272228509Sjhb } 273229821Salc 274229821Salc /* 275229821Salc * Zero the truncated part of the last page. 276229821Salc */ 277229821Salc base = length & PAGE_MASK; 278229821Salc if (base != 0) { 279229821Salc idx = OFF_TO_IDX(length); 280229821Salcretry: 281229821Salc m = vm_page_lookup(object, idx); 282229821Salc if (m != NULL) { 283229821Salc if ((m->oflags & VPO_BUSY) != 0 || 284229821Salc m->busy != 0) { 285229821Salc vm_page_sleep(m, "shmtrc"); 286229821Salc goto retry; 287229821Salc } 288229821Salc } else if (vm_pager_has_page(object, idx, NULL, NULL)) { 289229821Salc m = vm_page_alloc(object, idx, VM_ALLOC_NORMAL); 290229821Salc if (m == NULL) { 291229821Salc VM_OBJECT_UNLOCK(object); 292229821Salc VM_WAIT; 293229821Salc VM_OBJECT_LOCK(object); 294229821Salc goto retry; 295229821Salc } else if (m->valid != VM_PAGE_BITS_ALL) { 296229821Salc ma[0] = m; 297229821Salc rv = vm_pager_get_pages(object, ma, 1, 298229821Salc 0); 299229821Salc m = vm_page_lookup(object, idx); 300229821Salc } else 301229821Salc /* A cached page was reactivated. */ 302229821Salc rv = VM_PAGER_OK; 303229821Salc vm_page_lock(m); 304229821Salc if (rv == VM_PAGER_OK) { 305229821Salc vm_page_deactivate(m); 306229821Salc vm_page_unlock(m); 307229821Salc vm_page_wakeup(m); 308229821Salc } else { 309229821Salc vm_page_free(m); 310229821Salc vm_page_unlock(m); 311229821Salc VM_OBJECT_UNLOCK(object); 312229821Salc return (EIO); 313229821Salc } 314229821Salc } 315229821Salc if (m != NULL) { 316229821Salc pmap_zero_page_area(m, base, PAGE_SIZE - base); 317229821Salc KASSERT(m->valid == VM_PAGE_BITS_ALL, 318229821Salc ("shm_dotruncate: page %p is invalid", m)); 319229821Salc vm_page_dirty(m); 320229821Salc vm_pager_page_unswapped(m); 321229821Salc } 322229821Salc } 323194766Skib delta = ptoa(object->size - nobjsize); 324194766Skib 325175164Sjhb /* Toss in memory pages. */ 326175164Sjhb if (nobjsize < object->size) 327175164Sjhb vm_object_page_remove(object, nobjsize, object->size, 328223677Salc 0); 329175164Sjhb 330175164Sjhb /* Toss pages from swap. */ 331175164Sjhb if (object->type == OBJT_SWAP) 332194766Skib swap_pager_freespace(object, nobjsize, delta); 333175164Sjhb 334194766Skib /* Free the swap accounted for shm */ 335216128Strasz swap_release_by_cred(delta, object->cred); 336194766Skib object->charge -= delta; 337194766Skib } else { 338194766Skib /* Attempt to reserve the swap */ 339194766Skib delta = ptoa(nobjsize - object->size); 340216128Strasz if (!swap_reserve_by_cred(delta, object->cred)) { 341194766Skib VM_OBJECT_UNLOCK(object); 342194766Skib return (ENOMEM); 343194766Skib } 344194766Skib object->charge += delta; 345175164Sjhb } 346175164Sjhb shmfd->shm_size = length; 347175164Sjhb mtx_lock(&shm_timestamp_lock); 348175164Sjhb vfs_timestamp(&shmfd->shm_ctime); 349175164Sjhb shmfd->shm_mtime = shmfd->shm_ctime; 350175164Sjhb mtx_unlock(&shm_timestamp_lock); 351175164Sjhb object->size = nobjsize; 352175164Sjhb VM_OBJECT_UNLOCK(object); 353194766Skib return (0); 354175164Sjhb} 355175164Sjhb 356175164Sjhb/* 357175164Sjhb * shmfd object management including creation and reference counting 358175164Sjhb * routines. 359175164Sjhb */ 360175164Sjhbstatic struct shmfd * 361175164Sjhbshm_alloc(struct ucred *ucred, mode_t mode) 362175164Sjhb{ 363175164Sjhb struct shmfd *shmfd; 364175164Sjhb 365175164Sjhb shmfd = malloc(sizeof(*shmfd), M_SHMFD, M_WAITOK | M_ZERO); 366175164Sjhb shmfd->shm_size = 0; 367175164Sjhb shmfd->shm_uid = ucred->cr_uid; 368175164Sjhb shmfd->shm_gid = ucred->cr_gid; 369175164Sjhb shmfd->shm_mode = mode; 370175164Sjhb shmfd->shm_object = vm_pager_allocate(OBJT_DEFAULT, NULL, 371194766Skib shmfd->shm_size, VM_PROT_DEFAULT, 0, ucred); 372175164Sjhb KASSERT(shmfd->shm_object != NULL, ("shm_create: vm_pager_allocate")); 373178181Salc VM_OBJECT_LOCK(shmfd->shm_object); 374178181Salc vm_object_clear_flag(shmfd->shm_object, OBJ_ONEMAPPING); 375178181Salc vm_object_set_flag(shmfd->shm_object, OBJ_NOSPLIT); 376178181Salc VM_OBJECT_UNLOCK(shmfd->shm_object); 377175164Sjhb vfs_timestamp(&shmfd->shm_birthtime); 378175164Sjhb shmfd->shm_atime = shmfd->shm_mtime = shmfd->shm_ctime = 379175164Sjhb shmfd->shm_birthtime; 380175164Sjhb refcount_init(&shmfd->shm_refs, 1); 381175164Sjhb#ifdef MAC 382175164Sjhb mac_posixshm_init(shmfd); 383175164Sjhb mac_posixshm_create(ucred, shmfd); 384175164Sjhb#endif 385175164Sjhb 386175164Sjhb return (shmfd); 387175164Sjhb} 388175164Sjhb 389175164Sjhbstatic struct shmfd * 390175164Sjhbshm_hold(struct shmfd *shmfd) 391175164Sjhb{ 392175164Sjhb 393175164Sjhb refcount_acquire(&shmfd->shm_refs); 394175164Sjhb return (shmfd); 395175164Sjhb} 396175164Sjhb 397175164Sjhbstatic void 398175164Sjhbshm_drop(struct shmfd *shmfd) 399175164Sjhb{ 400175164Sjhb 401175164Sjhb if (refcount_release(&shmfd->shm_refs)) { 402175164Sjhb#ifdef MAC 403175164Sjhb mac_posixshm_destroy(shmfd); 404175164Sjhb#endif 405175164Sjhb vm_object_deallocate(shmfd->shm_object); 406175164Sjhb free(shmfd, M_SHMFD); 407175164Sjhb } 408175164Sjhb} 409175164Sjhb 410175164Sjhb/* 411175164Sjhb * Determine if the credentials have sufficient permissions for a 412175164Sjhb * specified combination of FREAD and FWRITE. 413175164Sjhb */ 414175164Sjhbstatic int 415175164Sjhbshm_access(struct shmfd *shmfd, struct ucred *ucred, int flags) 416175164Sjhb{ 417184413Strasz accmode_t accmode; 418224914Skib int error; 419175164Sjhb 420184413Strasz accmode = 0; 421175164Sjhb if (flags & FREAD) 422184413Strasz accmode |= VREAD; 423175164Sjhb if (flags & FWRITE) 424184413Strasz accmode |= VWRITE; 425224914Skib mtx_lock(&shm_timestamp_lock); 426224914Skib error = vaccess(VREG, shmfd->shm_mode, shmfd->shm_uid, shmfd->shm_gid, 427224914Skib accmode, ucred, NULL); 428224914Skib mtx_unlock(&shm_timestamp_lock); 429224914Skib return (error); 430175164Sjhb} 431175164Sjhb 432175164Sjhb/* 433175164Sjhb * Dictionary management. We maintain an in-kernel dictionary to map 434175164Sjhb * paths to shmfd objects. We use the FNV hash on the path to store 435175164Sjhb * the mappings in a hash table. 436175164Sjhb */ 437175164Sjhbstatic void 438175164Sjhbshm_dict_init(void *arg) 439175164Sjhb{ 440175164Sjhb 441175164Sjhb mtx_init(&shm_timestamp_lock, "shm timestamps", NULL, MTX_DEF); 442175164Sjhb sx_init(&shm_dict_lock, "shm dictionary"); 443175164Sjhb shm_dictionary = hashinit(1024, M_SHMFD, &shm_hash); 444175164Sjhb} 445175164SjhbSYSINIT(shm_dict_init, SI_SUB_SYSV_SHM, SI_ORDER_ANY, shm_dict_init, NULL); 446175164Sjhb 447175164Sjhbstatic struct shmfd * 448175164Sjhbshm_lookup(char *path, Fnv32_t fnv) 449175164Sjhb{ 450175164Sjhb struct shm_mapping *map; 451175164Sjhb 452175164Sjhb LIST_FOREACH(map, SHM_HASH(fnv), sm_link) { 453175164Sjhb if (map->sm_fnv != fnv) 454175164Sjhb continue; 455175164Sjhb if (strcmp(map->sm_path, path) == 0) 456175164Sjhb return (map->sm_shmfd); 457175164Sjhb } 458175164Sjhb 459175164Sjhb return (NULL); 460175164Sjhb} 461175164Sjhb 462175164Sjhbstatic void 463175164Sjhbshm_insert(char *path, Fnv32_t fnv, struct shmfd *shmfd) 464175164Sjhb{ 465175164Sjhb struct shm_mapping *map; 466175164Sjhb 467175164Sjhb map = malloc(sizeof(struct shm_mapping), M_SHMFD, M_WAITOK); 468175164Sjhb map->sm_path = path; 469175164Sjhb map->sm_fnv = fnv; 470175164Sjhb map->sm_shmfd = shm_hold(shmfd); 471175164Sjhb LIST_INSERT_HEAD(SHM_HASH(fnv), map, sm_link); 472175164Sjhb} 473175164Sjhb 474175164Sjhbstatic int 475175164Sjhbshm_remove(char *path, Fnv32_t fnv, struct ucred *ucred) 476175164Sjhb{ 477175164Sjhb struct shm_mapping *map; 478175164Sjhb int error; 479175164Sjhb 480175164Sjhb LIST_FOREACH(map, SHM_HASH(fnv), sm_link) { 481175164Sjhb if (map->sm_fnv != fnv) 482175164Sjhb continue; 483175164Sjhb if (strcmp(map->sm_path, path) == 0) { 484175164Sjhb#ifdef MAC 485175164Sjhb error = mac_posixshm_check_unlink(ucred, map->sm_shmfd); 486175164Sjhb if (error) 487175164Sjhb return (error); 488175164Sjhb#endif 489175164Sjhb error = shm_access(map->sm_shmfd, ucred, 490175164Sjhb FREAD | FWRITE); 491175164Sjhb if (error) 492175164Sjhb return (error); 493175164Sjhb LIST_REMOVE(map, sm_link); 494175164Sjhb shm_drop(map->sm_shmfd); 495175164Sjhb free(map->sm_path, M_SHMFD); 496175164Sjhb free(map, M_SHMFD); 497175164Sjhb return (0); 498175164Sjhb } 499175164Sjhb } 500175164Sjhb 501175164Sjhb return (ENOENT); 502175164Sjhb} 503175164Sjhb 504175164Sjhb/* System calls. */ 505175164Sjhbint 506225617Skmacysys_shm_open(struct thread *td, struct shm_open_args *uap) 507175164Sjhb{ 508175164Sjhb struct filedesc *fdp; 509175164Sjhb struct shmfd *shmfd; 510175164Sjhb struct file *fp; 511175164Sjhb char *path; 512175164Sjhb Fnv32_t fnv; 513175164Sjhb mode_t cmode; 514175164Sjhb int fd, error; 515175164Sjhb 516223692Sjonathan#ifdef CAPABILITY_MODE 517223692Sjonathan /* 518223692Sjonathan * shm_open(2) is only allowed for anonymous objects. 519223692Sjonathan */ 520223692Sjonathan if (IN_CAPABILITY_MODE(td) && (uap->path != SHM_ANON)) 521223692Sjonathan return (ECAPMODE); 522223692Sjonathan#endif 523223692Sjonathan 524175164Sjhb if ((uap->flags & O_ACCMODE) != O_RDONLY && 525175164Sjhb (uap->flags & O_ACCMODE) != O_RDWR) 526175164Sjhb return (EINVAL); 527175164Sjhb 528175164Sjhb if ((uap->flags & ~(O_ACCMODE | O_CREAT | O_EXCL | O_TRUNC)) != 0) 529175164Sjhb return (EINVAL); 530175164Sjhb 531175164Sjhb fdp = td->td_proc->p_fd; 532175164Sjhb cmode = (uap->mode & ~fdp->fd_cmask) & ACCESSPERMS; 533175164Sjhb 534220245Skib error = falloc(td, &fp, &fd, 0); 535175164Sjhb if (error) 536175164Sjhb return (error); 537175164Sjhb 538175164Sjhb /* A SHM_ANON path pointer creates an anonymous object. */ 539175164Sjhb if (uap->path == SHM_ANON) { 540175164Sjhb /* A read-only anonymous object is pointless. */ 541175164Sjhb if ((uap->flags & O_ACCMODE) == O_RDONLY) { 542175164Sjhb fdclose(fdp, fp, fd, td); 543175164Sjhb fdrop(fp, td); 544175164Sjhb return (EINVAL); 545175164Sjhb } 546175164Sjhb shmfd = shm_alloc(td->td_ucred, cmode); 547175164Sjhb } else { 548175164Sjhb path = malloc(MAXPATHLEN, M_SHMFD, M_WAITOK); 549175164Sjhb error = copyinstr(uap->path, path, MAXPATHLEN, NULL); 550175164Sjhb 551175164Sjhb /* Require paths to start with a '/' character. */ 552175164Sjhb if (error == 0 && path[0] != '/') 553175164Sjhb error = EINVAL; 554175164Sjhb if (error) { 555175164Sjhb fdclose(fdp, fp, fd, td); 556175164Sjhb fdrop(fp, td); 557175164Sjhb free(path, M_SHMFD); 558175164Sjhb return (error); 559175164Sjhb } 560175164Sjhb 561175164Sjhb fnv = fnv_32_str(path, FNV1_32_INIT); 562175164Sjhb sx_xlock(&shm_dict_lock); 563175164Sjhb shmfd = shm_lookup(path, fnv); 564175164Sjhb if (shmfd == NULL) { 565175164Sjhb /* Object does not yet exist, create it if requested. */ 566175164Sjhb if (uap->flags & O_CREAT) { 567225344Srwatson#ifdef MAC 568225344Srwatson error = mac_posixshm_check_create(td->td_ucred, 569225344Srwatson path); 570225344Srwatson if (error == 0) { 571225344Srwatson#endif 572225344Srwatson shmfd = shm_alloc(td->td_ucred, cmode); 573225344Srwatson shm_insert(path, fnv, shmfd); 574225344Srwatson#ifdef MAC 575225344Srwatson } 576225344Srwatson#endif 577175164Sjhb } else { 578175164Sjhb free(path, M_SHMFD); 579175164Sjhb error = ENOENT; 580175164Sjhb } 581175164Sjhb } else { 582175164Sjhb /* 583175164Sjhb * Object already exists, obtain a new 584175164Sjhb * reference if requested and permitted. 585175164Sjhb */ 586175164Sjhb free(path, M_SHMFD); 587175164Sjhb if ((uap->flags & (O_CREAT | O_EXCL)) == 588175164Sjhb (O_CREAT | O_EXCL)) 589175164Sjhb error = EEXIST; 590175164Sjhb else { 591175164Sjhb#ifdef MAC 592175164Sjhb error = mac_posixshm_check_open(td->td_ucred, 593225344Srwatson shmfd, FFLAGS(uap->flags & O_ACCMODE)); 594175164Sjhb if (error == 0) 595175164Sjhb#endif 596175164Sjhb error = shm_access(shmfd, td->td_ucred, 597175164Sjhb FFLAGS(uap->flags & O_ACCMODE)); 598175164Sjhb } 599175164Sjhb 600175164Sjhb /* 601175164Sjhb * Truncate the file back to zero length if 602175164Sjhb * O_TRUNC was specified and the object was 603175164Sjhb * opened with read/write. 604175164Sjhb */ 605175164Sjhb if (error == 0 && 606175164Sjhb (uap->flags & (O_ACCMODE | O_TRUNC)) == 607175164Sjhb (O_RDWR | O_TRUNC)) { 608175164Sjhb#ifdef MAC 609175164Sjhb error = mac_posixshm_check_truncate( 610175164Sjhb td->td_ucred, fp->f_cred, shmfd); 611175164Sjhb if (error == 0) 612175164Sjhb#endif 613175164Sjhb shm_dotruncate(shmfd, 0); 614175164Sjhb } 615175164Sjhb if (error == 0) 616175164Sjhb shm_hold(shmfd); 617175164Sjhb } 618175164Sjhb sx_xunlock(&shm_dict_lock); 619175164Sjhb 620175164Sjhb if (error) { 621175164Sjhb fdclose(fdp, fp, fd, td); 622175164Sjhb fdrop(fp, td); 623175164Sjhb return (error); 624175164Sjhb } 625175164Sjhb } 626175164Sjhb 627175164Sjhb finit(fp, FFLAGS(uap->flags & O_ACCMODE), DTYPE_SHM, shmfd, &shm_ops); 628175164Sjhb 629175164Sjhb FILEDESC_XLOCK(fdp); 630175164Sjhb if (fdp->fd_ofiles[fd] == fp) 631175164Sjhb fdp->fd_ofileflags[fd] |= UF_EXCLOSE; 632175164Sjhb FILEDESC_XUNLOCK(fdp); 633175164Sjhb td->td_retval[0] = fd; 634175164Sjhb fdrop(fp, td); 635175164Sjhb 636175164Sjhb return (0); 637175164Sjhb} 638175164Sjhb 639175164Sjhbint 640225617Skmacysys_shm_unlink(struct thread *td, struct shm_unlink_args *uap) 641175164Sjhb{ 642175164Sjhb char *path; 643175164Sjhb Fnv32_t fnv; 644175164Sjhb int error; 645175164Sjhb 646175164Sjhb path = malloc(MAXPATHLEN, M_TEMP, M_WAITOK); 647175164Sjhb error = copyinstr(uap->path, path, MAXPATHLEN, NULL); 648175164Sjhb if (error) { 649175164Sjhb free(path, M_TEMP); 650175164Sjhb return (error); 651175164Sjhb } 652175164Sjhb 653175164Sjhb fnv = fnv_32_str(path, FNV1_32_INIT); 654175164Sjhb sx_xlock(&shm_dict_lock); 655175164Sjhb error = shm_remove(path, fnv, td->td_ucred); 656175164Sjhb sx_xunlock(&shm_dict_lock); 657175164Sjhb free(path, M_TEMP); 658175164Sjhb 659175164Sjhb return (error); 660175164Sjhb} 661175164Sjhb 662175164Sjhb/* 663175164Sjhb * mmap() helper to validate mmap() requests against shm object state 664175164Sjhb * and give mmap() the vm_object to use for the mapping. 665175164Sjhb */ 666175164Sjhbint 667175164Sjhbshm_mmap(struct shmfd *shmfd, vm_size_t objsize, vm_ooffset_t foff, 668175164Sjhb vm_object_t *obj) 669175164Sjhb{ 670175164Sjhb 671175164Sjhb /* 672175164Sjhb * XXXRW: This validation is probably insufficient, and subject to 673175164Sjhb * sign errors. It should be fixed. 674175164Sjhb */ 675185533Skan if (foff >= shmfd->shm_size || 676185533Skan foff + objsize > round_page(shmfd->shm_size)) 677175164Sjhb return (EINVAL); 678175164Sjhb 679175164Sjhb mtx_lock(&shm_timestamp_lock); 680175164Sjhb vfs_timestamp(&shmfd->shm_atime); 681175164Sjhb mtx_unlock(&shm_timestamp_lock); 682175164Sjhb vm_object_reference(shmfd->shm_object); 683175164Sjhb *obj = shmfd->shm_object; 684175164Sjhb return (0); 685175164Sjhb} 686224914Skib 687224914Skibstatic int 688224914Skibshm_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, 689224914Skib struct thread *td) 690224914Skib{ 691224914Skib struct shmfd *shmfd; 692224914Skib int error; 693224914Skib 694224914Skib error = 0; 695224914Skib shmfd = fp->f_data; 696224914Skib mtx_lock(&shm_timestamp_lock); 697224914Skib /* 698224914Skib * SUSv4 says that x bits of permission need not be affected. 699224914Skib * Be consistent with our shm_open there. 700224914Skib */ 701224914Skib#ifdef MAC 702224914Skib error = mac_posixshm_check_setmode(active_cred, shmfd, mode); 703224914Skib if (error != 0) 704224914Skib goto out; 705224914Skib#endif 706224914Skib error = vaccess(VREG, shmfd->shm_mode, shmfd->shm_uid, 707224914Skib shmfd->shm_gid, VADMIN, active_cred, NULL); 708224914Skib if (error != 0) 709224914Skib goto out; 710224914Skib shmfd->shm_mode = mode & ACCESSPERMS; 711224914Skibout: 712224914Skib mtx_unlock(&shm_timestamp_lock); 713224914Skib return (error); 714224914Skib} 715224914Skib 716224914Skibstatic int 717224914Skibshm_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred, 718224914Skib struct thread *td) 719224914Skib{ 720224914Skib struct shmfd *shmfd; 721224914Skib int error; 722224914Skib 723224935Skib error = 0; 724224914Skib shmfd = fp->f_data; 725224914Skib mtx_lock(&shm_timestamp_lock); 726224914Skib#ifdef MAC 727224914Skib error = mac_posixshm_check_setowner(active_cred, shmfd, uid, gid); 728224914Skib if (error != 0) 729224914Skib goto out; 730224914Skib#endif 731224914Skib if (uid == (uid_t)-1) 732224914Skib uid = shmfd->shm_uid; 733224914Skib if (gid == (gid_t)-1) 734224914Skib gid = shmfd->shm_gid; 735224914Skib if (((uid != shmfd->shm_uid && uid != active_cred->cr_uid) || 736224914Skib (gid != shmfd->shm_gid && !groupmember(gid, active_cred))) && 737224914Skib (error = priv_check_cred(active_cred, PRIV_VFS_CHOWN, 0))) 738224914Skib goto out; 739224914Skib shmfd->shm_uid = uid; 740224914Skib shmfd->shm_gid = gid; 741224914Skibout: 742224914Skib mtx_unlock(&shm_timestamp_lock); 743224914Skib return (error); 744224914Skib} 745228509Sjhb 746228509Sjhb/* 747228509Sjhb * Helper routines to allow the backing object of a shared memory file 748228509Sjhb * descriptor to be mapped in the kernel. 749228509Sjhb */ 750228509Sjhbint 751228509Sjhbshm_map(struct file *fp, size_t size, off_t offset, void **memp) 752228509Sjhb{ 753228509Sjhb struct shmfd *shmfd; 754228509Sjhb vm_offset_t kva, ofs; 755228509Sjhb vm_object_t obj; 756228509Sjhb int rv; 757228509Sjhb 758228509Sjhb if (fp->f_type != DTYPE_SHM) 759228509Sjhb return (EINVAL); 760228509Sjhb shmfd = fp->f_data; 761228509Sjhb obj = shmfd->shm_object; 762228509Sjhb VM_OBJECT_LOCK(obj); 763228509Sjhb /* 764228509Sjhb * XXXRW: This validation is probably insufficient, and subject to 765228509Sjhb * sign errors. It should be fixed. 766228509Sjhb */ 767228509Sjhb if (offset >= shmfd->shm_size || 768228509Sjhb offset + size > round_page(shmfd->shm_size)) { 769228509Sjhb VM_OBJECT_UNLOCK(obj); 770228509Sjhb return (EINVAL); 771228509Sjhb } 772228509Sjhb 773228509Sjhb shmfd->shm_kmappings++; 774228509Sjhb vm_object_reference_locked(obj); 775228509Sjhb VM_OBJECT_UNLOCK(obj); 776228509Sjhb 777228509Sjhb /* Map the object into the kernel_map and wire it. */ 778228509Sjhb kva = vm_map_min(kernel_map); 779228509Sjhb ofs = offset & PAGE_MASK; 780228509Sjhb offset = trunc_page(offset); 781228509Sjhb size = round_page(size + ofs); 782228509Sjhb rv = vm_map_find(kernel_map, obj, offset, &kva, size, 783228509Sjhb VMFS_ALIGNED_SPACE, VM_PROT_READ | VM_PROT_WRITE, 784228509Sjhb VM_PROT_READ | VM_PROT_WRITE, 0); 785228509Sjhb if (rv == KERN_SUCCESS) { 786228509Sjhb rv = vm_map_wire(kernel_map, kva, kva + size, 787228509Sjhb VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES); 788228509Sjhb if (rv == KERN_SUCCESS) { 789228509Sjhb *memp = (void *)(kva + ofs); 790228509Sjhb return (0); 791228509Sjhb } 792228509Sjhb vm_map_remove(kernel_map, kva, kva + size); 793228509Sjhb } else 794228509Sjhb vm_object_deallocate(obj); 795228509Sjhb 796228509Sjhb /* On failure, drop our mapping reference. */ 797228509Sjhb VM_OBJECT_LOCK(obj); 798228509Sjhb shmfd->shm_kmappings--; 799228509Sjhb VM_OBJECT_UNLOCK(obj); 800228509Sjhb 801228533Sjhb return (vm_mmap_to_errno(rv)); 802228509Sjhb} 803228509Sjhb 804228509Sjhb/* 805228509Sjhb * We require the caller to unmap the entire entry. This allows us to 806228509Sjhb * safely decrement shm_kmappings when a mapping is removed. 807228509Sjhb */ 808228509Sjhbint 809228509Sjhbshm_unmap(struct file *fp, void *mem, size_t size) 810228509Sjhb{ 811228509Sjhb struct shmfd *shmfd; 812228509Sjhb vm_map_entry_t entry; 813228509Sjhb vm_offset_t kva, ofs; 814228509Sjhb vm_object_t obj; 815228509Sjhb vm_pindex_t pindex; 816228509Sjhb vm_prot_t prot; 817228509Sjhb boolean_t wired; 818228509Sjhb vm_map_t map; 819228509Sjhb int rv; 820228509Sjhb 821228509Sjhb if (fp->f_type != DTYPE_SHM) 822228509Sjhb return (EINVAL); 823228509Sjhb shmfd = fp->f_data; 824228509Sjhb kva = (vm_offset_t)mem; 825228509Sjhb ofs = kva & PAGE_MASK; 826228509Sjhb kva = trunc_page(kva); 827228509Sjhb size = round_page(size + ofs); 828228509Sjhb map = kernel_map; 829228509Sjhb rv = vm_map_lookup(&map, kva, VM_PROT_READ | VM_PROT_WRITE, &entry, 830228509Sjhb &obj, &pindex, &prot, &wired); 831228509Sjhb if (rv != KERN_SUCCESS) 832228509Sjhb return (EINVAL); 833228509Sjhb if (entry->start != kva || entry->end != kva + size) { 834228509Sjhb vm_map_lookup_done(map, entry); 835228509Sjhb return (EINVAL); 836228509Sjhb } 837228509Sjhb vm_map_lookup_done(map, entry); 838228509Sjhb if (obj != shmfd->shm_object) 839228509Sjhb return (EINVAL); 840228509Sjhb vm_map_remove(map, kva, kva + size); 841228509Sjhb VM_OBJECT_LOCK(obj); 842228509Sjhb KASSERT(shmfd->shm_kmappings > 0, ("shm_unmap: object not mapped")); 843228509Sjhb shmfd->shm_kmappings--; 844228509Sjhb VM_OBJECT_UNLOCK(obj); 845228509Sjhb return (0); 846228509Sjhb} 847