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: stable/10/sys/kern/uipc_shm.c 325783 2017-11-13 23:21:17Z jamie $"); 46175164Sjhb 47223692Sjonathan#include "opt_capsicum.h" 48269742Srpaulo#include "opt_ktrace.h" 49223692Sjonathan 50175164Sjhb#include <sys/param.h> 51280258Srwatson#include <sys/capsicum.h> 52271399Sjhb#include <sys/conf.h> 53175164Sjhb#include <sys/fcntl.h> 54175164Sjhb#include <sys/file.h> 55175164Sjhb#include <sys/filedesc.h> 56175164Sjhb#include <sys/fnv_hash.h> 57175164Sjhb#include <sys/kernel.h> 58269742Srpaulo#include <sys/uio.h> 59269742Srpaulo#include <sys/signal.h> 60325783Sjamie#include <sys/jail.h> 61269742Srpaulo#include <sys/ktrace.h> 62175164Sjhb#include <sys/lock.h> 63175164Sjhb#include <sys/malloc.h> 64175164Sjhb#include <sys/mman.h> 65175164Sjhb#include <sys/mutex.h> 66224914Skib#include <sys/priv.h> 67175164Sjhb#include <sys/proc.h> 68175164Sjhb#include <sys/refcount.h> 69175164Sjhb#include <sys/resourcevar.h> 70248084Sattilio#include <sys/rwlock.h> 71175164Sjhb#include <sys/stat.h> 72175164Sjhb#include <sys/sysctl.h> 73175164Sjhb#include <sys/sysproto.h> 74175164Sjhb#include <sys/systm.h> 75175164Sjhb#include <sys/sx.h> 76175164Sjhb#include <sys/time.h> 77175164Sjhb#include <sys/vnode.h> 78254603Skib#include <sys/unistd.h> 79175164Sjhb 80175164Sjhb#include <security/mac/mac_framework.h> 81175164Sjhb 82175164Sjhb#include <vm/vm.h> 83175164Sjhb#include <vm/vm_param.h> 84175164Sjhb#include <vm/pmap.h> 85228533Sjhb#include <vm/vm_extern.h> 86175164Sjhb#include <vm/vm_map.h> 87228509Sjhb#include <vm/vm_kern.h> 88175164Sjhb#include <vm/vm_object.h> 89175164Sjhb#include <vm/vm_page.h> 90229821Salc#include <vm/vm_pageout.h> 91175164Sjhb#include <vm/vm_pager.h> 92175164Sjhb#include <vm/swap_pager.h> 93175164Sjhb 94175164Sjhbstruct shm_mapping { 95175164Sjhb char *sm_path; 96175164Sjhb Fnv32_t sm_fnv; 97175164Sjhb struct shmfd *sm_shmfd; 98175164Sjhb LIST_ENTRY(shm_mapping) sm_link; 99175164Sjhb}; 100175164Sjhb 101175164Sjhbstatic MALLOC_DEFINE(M_SHMFD, "shmfd", "shared memory file descriptor"); 102175164Sjhbstatic LIST_HEAD(, shm_mapping) *shm_dictionary; 103175164Sjhbstatic struct sx shm_dict_lock; 104175164Sjhbstatic struct mtx shm_timestamp_lock; 105175164Sjhbstatic u_long shm_hash; 106271399Sjhbstatic struct unrhdr *shm_ino_unr; 107271399Sjhbstatic dev_t shm_dev_ino; 108175164Sjhb 109175164Sjhb#define SHM_HASH(fnv) (&shm_dictionary[(fnv) & shm_hash]) 110175164Sjhb 111175164Sjhbstatic int shm_access(struct shmfd *shmfd, struct ucred *ucred, int flags); 112175164Sjhbstatic struct shmfd *shm_alloc(struct ucred *ucred, mode_t mode); 113271399Sjhbstatic void shm_init(void *arg); 114175164Sjhbstatic void shm_drop(struct shmfd *shmfd); 115175164Sjhbstatic struct shmfd *shm_hold(struct shmfd *shmfd); 116175164Sjhbstatic void shm_insert(char *path, Fnv32_t fnv, struct shmfd *shmfd); 117175164Sjhbstatic struct shmfd *shm_lookup(char *path, Fnv32_t fnv); 118175164Sjhbstatic int shm_remove(char *path, Fnv32_t fnv, struct ucred *ucred); 119194766Skibstatic int shm_dotruncate(struct shmfd *shmfd, off_t length); 120175164Sjhb 121175164Sjhbstatic fo_rdwr_t shm_read; 122175164Sjhbstatic fo_rdwr_t shm_write; 123175164Sjhbstatic fo_truncate_t shm_truncate; 124175164Sjhbstatic fo_ioctl_t shm_ioctl; 125175164Sjhbstatic fo_poll_t shm_poll; 126175164Sjhbstatic fo_kqfilter_t shm_kqfilter; 127175164Sjhbstatic fo_stat_t shm_stat; 128175164Sjhbstatic fo_close_t shm_close; 129224914Skibstatic fo_chmod_t shm_chmod; 130224914Skibstatic fo_chown_t shm_chown; 131254603Skibstatic fo_seek_t shm_seek; 132175164Sjhb 133175164Sjhb/* File descriptor operations. */ 134175164Sjhbstatic struct fileops shm_ops = { 135175164Sjhb .fo_read = shm_read, 136175164Sjhb .fo_write = shm_write, 137175164Sjhb .fo_truncate = shm_truncate, 138175164Sjhb .fo_ioctl = shm_ioctl, 139175164Sjhb .fo_poll = shm_poll, 140175164Sjhb .fo_kqfilter = shm_kqfilter, 141175164Sjhb .fo_stat = shm_stat, 142175164Sjhb .fo_close = shm_close, 143224914Skib .fo_chmod = shm_chmod, 144224914Skib .fo_chown = shm_chown, 145255467Skib .fo_sendfile = vn_sendfile, 146254603Skib .fo_seek = shm_seek, 147254603Skib .fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE 148175164Sjhb}; 149175164Sjhb 150175164SjhbFEATURE(posix_shm, "POSIX shared memory"); 151175164Sjhb 152175164Sjhbstatic int 153254601Skibuiomove_object_page(vm_object_t obj, size_t len, struct uio *uio) 154254601Skib{ 155254601Skib vm_page_t m; 156254601Skib vm_pindex_t idx; 157254601Skib size_t tlen; 158254601Skib int error, offset, rv; 159254601Skib 160254601Skib idx = OFF_TO_IDX(uio->uio_offset); 161254601Skib offset = uio->uio_offset & PAGE_MASK; 162254601Skib tlen = MIN(PAGE_SIZE - offset, len); 163254601Skib 164254601Skib VM_OBJECT_WLOCK(obj); 165254601Skib 166254601Skib /* 167254601Skib * Parallel reads of the page content from disk are prevented 168254601Skib * by exclusive busy. 169254601Skib * 170254601Skib * Although the tmpfs vnode lock is held here, it is 171254601Skib * nonetheless safe to sleep waiting for a free page. The 172254601Skib * pageout daemon does not need to acquire the tmpfs vnode 173254601Skib * lock to page out tobj's pages because tobj is a OBJT_SWAP 174254601Skib * type object. 175254601Skib */ 176254649Skib m = vm_page_grab(obj, idx, VM_ALLOC_NORMAL); 177254601Skib if (m->valid != VM_PAGE_BITS_ALL) { 178254601Skib if (vm_pager_has_page(obj, idx, NULL, NULL)) { 179254601Skib rv = vm_pager_get_pages(obj, &m, 1, 0); 180254601Skib m = vm_page_lookup(obj, idx); 181254601Skib if (m == NULL) { 182254601Skib printf( 183254601Skib "uiomove_object: vm_obj %p idx %jd null lookup rv %d\n", 184254601Skib obj, idx, rv); 185254601Skib VM_OBJECT_WUNLOCK(obj); 186254601Skib return (EIO); 187254601Skib } 188254601Skib if (rv != VM_PAGER_OK) { 189254601Skib printf( 190254601Skib "uiomove_object: vm_obj %p idx %jd valid %x pager error %d\n", 191254601Skib obj, idx, m->valid, rv); 192254601Skib vm_page_lock(m); 193254601Skib vm_page_free(m); 194254601Skib vm_page_unlock(m); 195254601Skib VM_OBJECT_WUNLOCK(obj); 196254601Skib return (EIO); 197254601Skib } 198254601Skib } else 199254601Skib vm_page_zero_invalid(m, TRUE); 200254601Skib } 201254601Skib vm_page_xunbusy(m); 202254601Skib vm_page_lock(m); 203254601Skib vm_page_hold(m); 204270205Skib if (m->queue == PQ_NONE) { 205270205Skib vm_page_deactivate(m); 206270205Skib } else { 207270205Skib /* Requeue to maintain LRU ordering. */ 208270205Skib vm_page_requeue(m); 209270205Skib } 210254601Skib vm_page_unlock(m); 211254601Skib VM_OBJECT_WUNLOCK(obj); 212254601Skib error = uiomove_fromphys(&m, offset, tlen, uio); 213254601Skib if (uio->uio_rw == UIO_WRITE && error == 0) { 214254601Skib VM_OBJECT_WLOCK(obj); 215254601Skib vm_page_dirty(m); 216269495Skib vm_pager_page_unswapped(m); 217254601Skib VM_OBJECT_WUNLOCK(obj); 218254601Skib } 219254601Skib vm_page_lock(m); 220254601Skib vm_page_unhold(m); 221254601Skib vm_page_unlock(m); 222254601Skib 223254601Skib return (error); 224254601Skib} 225254601Skib 226254601Skibint 227254601Skibuiomove_object(vm_object_t obj, off_t obj_size, struct uio *uio) 228254601Skib{ 229254601Skib ssize_t resid; 230254601Skib size_t len; 231254601Skib int error; 232254601Skib 233254601Skib error = 0; 234254601Skib while ((resid = uio->uio_resid) > 0) { 235254601Skib if (obj_size <= uio->uio_offset) 236254601Skib break; 237254601Skib len = MIN(obj_size - uio->uio_offset, resid); 238254601Skib if (len == 0) 239254601Skib break; 240254601Skib error = uiomove_object_page(obj, len, uio); 241254601Skib if (error != 0 || resid == uio->uio_resid) 242254601Skib break; 243254601Skib } 244254601Skib return (error); 245254601Skib} 246254601Skib 247254601Skibstatic int 248254603Skibshm_seek(struct file *fp, off_t offset, int whence, struct thread *td) 249254603Skib{ 250254603Skib struct shmfd *shmfd; 251254603Skib off_t foffset; 252254603Skib int error; 253254603Skib 254254603Skib shmfd = fp->f_data; 255254603Skib foffset = foffset_lock(fp, 0); 256254603Skib error = 0; 257254603Skib switch (whence) { 258254603Skib case L_INCR: 259254603Skib if (foffset < 0 || 260254603Skib (offset > 0 && foffset > OFF_MAX - offset)) { 261254603Skib error = EOVERFLOW; 262254603Skib break; 263254603Skib } 264254603Skib offset += foffset; 265254603Skib break; 266254603Skib case L_XTND: 267254603Skib if (offset > 0 && shmfd->shm_size > OFF_MAX - offset) { 268254603Skib error = EOVERFLOW; 269254603Skib break; 270254603Skib } 271254603Skib offset += shmfd->shm_size; 272254603Skib break; 273254603Skib case L_SET: 274254603Skib break; 275254603Skib default: 276254603Skib error = EINVAL; 277254603Skib } 278254603Skib if (error == 0) { 279254603Skib if (offset < 0 || offset > shmfd->shm_size) 280254603Skib error = EINVAL; 281254603Skib else 282254603Skib *(off_t *)(td->td_retval) = offset; 283254603Skib } 284254603Skib foffset_unlock(fp, offset, error != 0 ? FOF_NOUPDATE : 0); 285254603Skib return (error); 286254603Skib} 287254603Skib 288254603Skibstatic int 289175164Sjhbshm_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 290175164Sjhb int flags, struct thread *td) 291175164Sjhb{ 292254603Skib struct shmfd *shmfd; 293254603Skib void *rl_cookie; 294254603Skib int error; 295175164Sjhb 296254603Skib shmfd = fp->f_data; 297254603Skib#ifdef MAC 298254603Skib error = mac_posixshm_check_read(active_cred, fp->f_cred, shmfd); 299254603Skib if (error) 300254603Skib return (error); 301254603Skib#endif 302302323Sjilles foffset_lock_uio(fp, uio, flags); 303302323Sjilles rl_cookie = rangelock_rlock(&shmfd->shm_rl, uio->uio_offset, 304302323Sjilles uio->uio_offset + uio->uio_resid, &shmfd->shm_mtx); 305254603Skib error = uiomove_object(shmfd->shm_object, shmfd->shm_size, uio); 306254603Skib rangelock_unlock(&shmfd->shm_rl, rl_cookie, &shmfd->shm_mtx); 307254603Skib foffset_unlock_uio(fp, uio, flags); 308254603Skib return (error); 309175164Sjhb} 310175164Sjhb 311175164Sjhbstatic int 312175164Sjhbshm_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 313175164Sjhb int flags, struct thread *td) 314175164Sjhb{ 315254603Skib struct shmfd *shmfd; 316254603Skib void *rl_cookie; 317254603Skib int error; 318175164Sjhb 319254603Skib shmfd = fp->f_data; 320254603Skib#ifdef MAC 321254603Skib error = mac_posixshm_check_write(active_cred, fp->f_cred, shmfd); 322254603Skib if (error) 323254603Skib return (error); 324254603Skib#endif 325254603Skib foffset_lock_uio(fp, uio, flags); 326254603Skib if ((flags & FOF_OFFSET) == 0) { 327254603Skib rl_cookie = rangelock_wlock(&shmfd->shm_rl, 0, OFF_MAX, 328254603Skib &shmfd->shm_mtx); 329254603Skib } else { 330254603Skib rl_cookie = rangelock_wlock(&shmfd->shm_rl, uio->uio_offset, 331254603Skib uio->uio_offset + uio->uio_resid, &shmfd->shm_mtx); 332254603Skib } 333254603Skib 334254603Skib error = uiomove_object(shmfd->shm_object, shmfd->shm_size, uio); 335254603Skib rangelock_unlock(&shmfd->shm_rl, rl_cookie, &shmfd->shm_mtx); 336254603Skib foffset_unlock_uio(fp, uio, flags); 337254603Skib return (error); 338175164Sjhb} 339175164Sjhb 340175164Sjhbstatic int 341175164Sjhbshm_truncate(struct file *fp, off_t length, struct ucred *active_cred, 342175164Sjhb struct thread *td) 343175164Sjhb{ 344175164Sjhb struct shmfd *shmfd; 345175164Sjhb#ifdef MAC 346175164Sjhb int error; 347175164Sjhb#endif 348175164Sjhb 349175164Sjhb shmfd = fp->f_data; 350175164Sjhb#ifdef MAC 351175164Sjhb error = mac_posixshm_check_truncate(active_cred, fp->f_cred, shmfd); 352175164Sjhb if (error) 353175164Sjhb return (error); 354175164Sjhb#endif 355194766Skib return (shm_dotruncate(shmfd, length)); 356175164Sjhb} 357175164Sjhb 358175164Sjhbstatic int 359175164Sjhbshm_ioctl(struct file *fp, u_long com, void *data, 360175164Sjhb struct ucred *active_cred, struct thread *td) 361175164Sjhb{ 362175164Sjhb 363175164Sjhb return (EOPNOTSUPP); 364175164Sjhb} 365175164Sjhb 366175164Sjhbstatic int 367175164Sjhbshm_poll(struct file *fp, int events, struct ucred *active_cred, 368175164Sjhb struct thread *td) 369175164Sjhb{ 370175164Sjhb 371175164Sjhb return (EOPNOTSUPP); 372175164Sjhb} 373175164Sjhb 374175164Sjhbstatic int 375175164Sjhbshm_kqfilter(struct file *fp, struct knote *kn) 376175164Sjhb{ 377175164Sjhb 378175164Sjhb return (EOPNOTSUPP); 379175164Sjhb} 380175164Sjhb 381175164Sjhbstatic int 382175164Sjhbshm_stat(struct file *fp, struct stat *sb, struct ucred *active_cred, 383175164Sjhb struct thread *td) 384175164Sjhb{ 385175164Sjhb struct shmfd *shmfd; 386175164Sjhb#ifdef MAC 387175164Sjhb int error; 388175164Sjhb#endif 389175164Sjhb 390175164Sjhb shmfd = fp->f_data; 391175164Sjhb 392175164Sjhb#ifdef MAC 393175164Sjhb error = mac_posixshm_check_stat(active_cred, fp->f_cred, shmfd); 394175164Sjhb if (error) 395175164Sjhb return (error); 396175164Sjhb#endif 397175164Sjhb 398175164Sjhb /* 399175164Sjhb * Attempt to return sanish values for fstat() on a memory file 400175164Sjhb * descriptor. 401175164Sjhb */ 402175164Sjhb bzero(sb, sizeof(*sb)); 403175164Sjhb sb->st_blksize = PAGE_SIZE; 404175164Sjhb sb->st_size = shmfd->shm_size; 405175164Sjhb sb->st_blocks = (sb->st_size + sb->st_blksize - 1) / sb->st_blksize; 406224914Skib mtx_lock(&shm_timestamp_lock); 407205792Sed sb->st_atim = shmfd->shm_atime; 408205792Sed sb->st_ctim = shmfd->shm_ctime; 409205792Sed sb->st_mtim = shmfd->shm_mtime; 410224914Skib sb->st_birthtim = shmfd->shm_birthtime; 411224914Skib sb->st_mode = S_IFREG | shmfd->shm_mode; /* XXX */ 412175164Sjhb sb->st_uid = shmfd->shm_uid; 413175164Sjhb sb->st_gid = shmfd->shm_gid; 414224914Skib mtx_unlock(&shm_timestamp_lock); 415271399Sjhb sb->st_dev = shm_dev_ino; 416271399Sjhb sb->st_ino = shmfd->shm_ino; 417175164Sjhb 418175164Sjhb return (0); 419175164Sjhb} 420175164Sjhb 421175164Sjhbstatic int 422175164Sjhbshm_close(struct file *fp, struct thread *td) 423175164Sjhb{ 424175164Sjhb struct shmfd *shmfd; 425175164Sjhb 426175164Sjhb shmfd = fp->f_data; 427175164Sjhb fp->f_data = NULL; 428175164Sjhb shm_drop(shmfd); 429175164Sjhb 430175164Sjhb return (0); 431175164Sjhb} 432175164Sjhb 433194766Skibstatic int 434175164Sjhbshm_dotruncate(struct shmfd *shmfd, off_t length) 435175164Sjhb{ 436175164Sjhb vm_object_t object; 437229821Salc vm_page_t m, ma[1]; 438229821Salc vm_pindex_t idx, nobjsize; 439194766Skib vm_ooffset_t delta; 440229821Salc int base, rv; 441175164Sjhb 442321361Salc KASSERT(length >= 0, ("shm_dotruncate: length < 0")); 443175164Sjhb object = shmfd->shm_object; 444248084Sattilio VM_OBJECT_WLOCK(object); 445175164Sjhb if (length == shmfd->shm_size) { 446248084Sattilio VM_OBJECT_WUNLOCK(object); 447194766Skib return (0); 448175164Sjhb } 449175164Sjhb nobjsize = OFF_TO_IDX(length + PAGE_MASK); 450175164Sjhb 451175164Sjhb /* Are we shrinking? If so, trim the end. */ 452175164Sjhb if (length < shmfd->shm_size) { 453228509Sjhb /* 454228509Sjhb * Disallow any requests to shrink the size if this 455228509Sjhb * object is mapped into the kernel. 456228509Sjhb */ 457228509Sjhb if (shmfd->shm_kmappings > 0) { 458248084Sattilio VM_OBJECT_WUNLOCK(object); 459228509Sjhb return (EBUSY); 460228509Sjhb } 461229821Salc 462229821Salc /* 463229821Salc * Zero the truncated part of the last page. 464229821Salc */ 465229821Salc base = length & PAGE_MASK; 466229821Salc if (base != 0) { 467229821Salc idx = OFF_TO_IDX(length); 468229821Salcretry: 469229821Salc m = vm_page_lookup(object, idx); 470229821Salc if (m != NULL) { 471254138Sattilio if (vm_page_sleep_if_busy(m, "shmtrc")) 472229821Salc goto retry; 473229821Salc } else if (vm_pager_has_page(object, idx, NULL, NULL)) { 474229821Salc m = vm_page_alloc(object, idx, VM_ALLOC_NORMAL); 475229821Salc if (m == NULL) { 476248084Sattilio VM_OBJECT_WUNLOCK(object); 477229821Salc VM_WAIT; 478248084Sattilio VM_OBJECT_WLOCK(object); 479229821Salc goto retry; 480229821Salc } else if (m->valid != VM_PAGE_BITS_ALL) { 481229821Salc ma[0] = m; 482229821Salc rv = vm_pager_get_pages(object, ma, 1, 483229821Salc 0); 484229821Salc m = vm_page_lookup(object, idx); 485229821Salc } else 486229821Salc /* A cached page was reactivated. */ 487229821Salc rv = VM_PAGER_OK; 488229821Salc vm_page_lock(m); 489229821Salc if (rv == VM_PAGER_OK) { 490229821Salc vm_page_deactivate(m); 491229821Salc vm_page_unlock(m); 492254138Sattilio vm_page_xunbusy(m); 493229821Salc } else { 494229821Salc vm_page_free(m); 495229821Salc vm_page_unlock(m); 496248084Sattilio VM_OBJECT_WUNLOCK(object); 497229821Salc return (EIO); 498229821Salc } 499229821Salc } 500229821Salc if (m != NULL) { 501229821Salc pmap_zero_page_area(m, base, PAGE_SIZE - base); 502229821Salc KASSERT(m->valid == VM_PAGE_BITS_ALL, 503229821Salc ("shm_dotruncate: page %p is invalid", m)); 504229821Salc vm_page_dirty(m); 505229821Salc vm_pager_page_unswapped(m); 506229821Salc } 507229821Salc } 508321361Salc delta = IDX_TO_OFF(object->size - nobjsize); 509194766Skib 510175164Sjhb /* Toss in memory pages. */ 511175164Sjhb if (nobjsize < object->size) 512175164Sjhb vm_object_page_remove(object, nobjsize, object->size, 513223677Salc 0); 514175164Sjhb 515175164Sjhb /* Toss pages from swap. */ 516175164Sjhb if (object->type == OBJT_SWAP) 517194766Skib swap_pager_freespace(object, nobjsize, delta); 518175164Sjhb 519194766Skib /* Free the swap accounted for shm */ 520216128Strasz swap_release_by_cred(delta, object->cred); 521194766Skib object->charge -= delta; 522194766Skib } else { 523321361Salc /* Try to reserve additional swap space. */ 524321361Salc delta = IDX_TO_OFF(nobjsize - object->size); 525216128Strasz if (!swap_reserve_by_cred(delta, object->cred)) { 526248084Sattilio VM_OBJECT_WUNLOCK(object); 527194766Skib return (ENOMEM); 528194766Skib } 529194766Skib object->charge += delta; 530175164Sjhb } 531175164Sjhb shmfd->shm_size = length; 532175164Sjhb mtx_lock(&shm_timestamp_lock); 533175164Sjhb vfs_timestamp(&shmfd->shm_ctime); 534175164Sjhb shmfd->shm_mtime = shmfd->shm_ctime; 535175164Sjhb mtx_unlock(&shm_timestamp_lock); 536175164Sjhb object->size = nobjsize; 537248084Sattilio VM_OBJECT_WUNLOCK(object); 538194766Skib return (0); 539175164Sjhb} 540175164Sjhb 541175164Sjhb/* 542175164Sjhb * shmfd object management including creation and reference counting 543175164Sjhb * routines. 544175164Sjhb */ 545175164Sjhbstatic struct shmfd * 546175164Sjhbshm_alloc(struct ucred *ucred, mode_t mode) 547175164Sjhb{ 548175164Sjhb struct shmfd *shmfd; 549271399Sjhb int ino; 550175164Sjhb 551175164Sjhb shmfd = malloc(sizeof(*shmfd), M_SHMFD, M_WAITOK | M_ZERO); 552175164Sjhb shmfd->shm_size = 0; 553175164Sjhb shmfd->shm_uid = ucred->cr_uid; 554175164Sjhb shmfd->shm_gid = ucred->cr_gid; 555175164Sjhb shmfd->shm_mode = mode; 556175164Sjhb shmfd->shm_object = vm_pager_allocate(OBJT_DEFAULT, NULL, 557194766Skib shmfd->shm_size, VM_PROT_DEFAULT, 0, ucred); 558175164Sjhb KASSERT(shmfd->shm_object != NULL, ("shm_create: vm_pager_allocate")); 559281778Salc shmfd->shm_object->pg_color = 0; 560248084Sattilio VM_OBJECT_WLOCK(shmfd->shm_object); 561178181Salc vm_object_clear_flag(shmfd->shm_object, OBJ_ONEMAPPING); 562281778Salc vm_object_set_flag(shmfd->shm_object, OBJ_COLORED | OBJ_NOSPLIT); 563248084Sattilio VM_OBJECT_WUNLOCK(shmfd->shm_object); 564175164Sjhb vfs_timestamp(&shmfd->shm_birthtime); 565175164Sjhb shmfd->shm_atime = shmfd->shm_mtime = shmfd->shm_ctime = 566175164Sjhb shmfd->shm_birthtime; 567271399Sjhb ino = alloc_unr(shm_ino_unr); 568271399Sjhb if (ino == -1) 569271399Sjhb shmfd->shm_ino = 0; 570271399Sjhb else 571271399Sjhb shmfd->shm_ino = ino; 572175164Sjhb refcount_init(&shmfd->shm_refs, 1); 573254603Skib mtx_init(&shmfd->shm_mtx, "shmrl", NULL, MTX_DEF); 574254603Skib rangelock_init(&shmfd->shm_rl); 575175164Sjhb#ifdef MAC 576175164Sjhb mac_posixshm_init(shmfd); 577175164Sjhb mac_posixshm_create(ucred, shmfd); 578175164Sjhb#endif 579175164Sjhb 580175164Sjhb return (shmfd); 581175164Sjhb} 582175164Sjhb 583175164Sjhbstatic struct shmfd * 584175164Sjhbshm_hold(struct shmfd *shmfd) 585175164Sjhb{ 586175164Sjhb 587175164Sjhb refcount_acquire(&shmfd->shm_refs); 588175164Sjhb return (shmfd); 589175164Sjhb} 590175164Sjhb 591175164Sjhbstatic void 592175164Sjhbshm_drop(struct shmfd *shmfd) 593175164Sjhb{ 594175164Sjhb 595175164Sjhb if (refcount_release(&shmfd->shm_refs)) { 596175164Sjhb#ifdef MAC 597175164Sjhb mac_posixshm_destroy(shmfd); 598175164Sjhb#endif 599254603Skib rangelock_destroy(&shmfd->shm_rl); 600254603Skib mtx_destroy(&shmfd->shm_mtx); 601175164Sjhb vm_object_deallocate(shmfd->shm_object); 602271399Sjhb if (shmfd->shm_ino != 0) 603271399Sjhb free_unr(shm_ino_unr, shmfd->shm_ino); 604175164Sjhb free(shmfd, M_SHMFD); 605175164Sjhb } 606175164Sjhb} 607175164Sjhb 608175164Sjhb/* 609175164Sjhb * Determine if the credentials have sufficient permissions for a 610175164Sjhb * specified combination of FREAD and FWRITE. 611175164Sjhb */ 612175164Sjhbstatic int 613175164Sjhbshm_access(struct shmfd *shmfd, struct ucred *ucred, int flags) 614175164Sjhb{ 615184413Strasz accmode_t accmode; 616224914Skib int error; 617175164Sjhb 618184413Strasz accmode = 0; 619175164Sjhb if (flags & FREAD) 620184413Strasz accmode |= VREAD; 621175164Sjhb if (flags & FWRITE) 622184413Strasz accmode |= VWRITE; 623224914Skib mtx_lock(&shm_timestamp_lock); 624224914Skib error = vaccess(VREG, shmfd->shm_mode, shmfd->shm_uid, shmfd->shm_gid, 625224914Skib accmode, ucred, NULL); 626224914Skib mtx_unlock(&shm_timestamp_lock); 627224914Skib return (error); 628175164Sjhb} 629175164Sjhb 630175164Sjhb/* 631175164Sjhb * Dictionary management. We maintain an in-kernel dictionary to map 632175164Sjhb * paths to shmfd objects. We use the FNV hash on the path to store 633175164Sjhb * the mappings in a hash table. 634175164Sjhb */ 635175164Sjhbstatic void 636271399Sjhbshm_init(void *arg) 637175164Sjhb{ 638175164Sjhb 639175164Sjhb mtx_init(&shm_timestamp_lock, "shm timestamps", NULL, MTX_DEF); 640175164Sjhb sx_init(&shm_dict_lock, "shm dictionary"); 641175164Sjhb shm_dictionary = hashinit(1024, M_SHMFD, &shm_hash); 642271399Sjhb shm_ino_unr = new_unrhdr(1, INT32_MAX, NULL); 643271399Sjhb KASSERT(shm_ino_unr != NULL, ("shm fake inodes not initialized")); 644271399Sjhb shm_dev_ino = devfs_alloc_cdp_inode(); 645271399Sjhb KASSERT(shm_dev_ino > 0, ("shm dev inode not initialized")); 646175164Sjhb} 647271399SjhbSYSINIT(shm_init, SI_SUB_SYSV_SHM, SI_ORDER_ANY, shm_init, NULL); 648175164Sjhb 649175164Sjhbstatic struct shmfd * 650175164Sjhbshm_lookup(char *path, Fnv32_t fnv) 651175164Sjhb{ 652175164Sjhb struct shm_mapping *map; 653175164Sjhb 654175164Sjhb LIST_FOREACH(map, SHM_HASH(fnv), sm_link) { 655175164Sjhb if (map->sm_fnv != fnv) 656175164Sjhb continue; 657175164Sjhb if (strcmp(map->sm_path, path) == 0) 658175164Sjhb return (map->sm_shmfd); 659175164Sjhb } 660175164Sjhb 661175164Sjhb return (NULL); 662175164Sjhb} 663175164Sjhb 664175164Sjhbstatic void 665175164Sjhbshm_insert(char *path, Fnv32_t fnv, struct shmfd *shmfd) 666175164Sjhb{ 667175164Sjhb struct shm_mapping *map; 668175164Sjhb 669175164Sjhb map = malloc(sizeof(struct shm_mapping), M_SHMFD, M_WAITOK); 670175164Sjhb map->sm_path = path; 671175164Sjhb map->sm_fnv = fnv; 672175164Sjhb map->sm_shmfd = shm_hold(shmfd); 673233760Sjhb shmfd->shm_path = path; 674175164Sjhb LIST_INSERT_HEAD(SHM_HASH(fnv), map, sm_link); 675175164Sjhb} 676175164Sjhb 677175164Sjhbstatic int 678175164Sjhbshm_remove(char *path, Fnv32_t fnv, struct ucred *ucred) 679175164Sjhb{ 680175164Sjhb struct shm_mapping *map; 681175164Sjhb int error; 682175164Sjhb 683175164Sjhb LIST_FOREACH(map, SHM_HASH(fnv), sm_link) { 684175164Sjhb if (map->sm_fnv != fnv) 685175164Sjhb continue; 686175164Sjhb if (strcmp(map->sm_path, path) == 0) { 687175164Sjhb#ifdef MAC 688175164Sjhb error = mac_posixshm_check_unlink(ucred, map->sm_shmfd); 689175164Sjhb if (error) 690175164Sjhb return (error); 691175164Sjhb#endif 692175164Sjhb error = shm_access(map->sm_shmfd, ucred, 693175164Sjhb FREAD | FWRITE); 694175164Sjhb if (error) 695175164Sjhb return (error); 696233760Sjhb map->sm_shmfd->shm_path = NULL; 697175164Sjhb LIST_REMOVE(map, sm_link); 698175164Sjhb shm_drop(map->sm_shmfd); 699175164Sjhb free(map->sm_path, M_SHMFD); 700175164Sjhb free(map, M_SHMFD); 701175164Sjhb return (0); 702175164Sjhb } 703175164Sjhb } 704175164Sjhb 705175164Sjhb return (ENOENT); 706175164Sjhb} 707175164Sjhb 708175164Sjhb/* System calls. */ 709175164Sjhbint 710225617Skmacysys_shm_open(struct thread *td, struct shm_open_args *uap) 711175164Sjhb{ 712175164Sjhb struct filedesc *fdp; 713175164Sjhb struct shmfd *shmfd; 714175164Sjhb struct file *fp; 715175164Sjhb char *path; 716325783Sjamie const char *pr_path; 717325783Sjamie size_t pr_pathlen; 718175164Sjhb Fnv32_t fnv; 719175164Sjhb mode_t cmode; 720175164Sjhb int fd, error; 721175164Sjhb 722223692Sjonathan#ifdef CAPABILITY_MODE 723223692Sjonathan /* 724223692Sjonathan * shm_open(2) is only allowed for anonymous objects. 725223692Sjonathan */ 726223692Sjonathan if (IN_CAPABILITY_MODE(td) && (uap->path != SHM_ANON)) 727223692Sjonathan return (ECAPMODE); 728223692Sjonathan#endif 729223692Sjonathan 730175164Sjhb if ((uap->flags & O_ACCMODE) != O_RDONLY && 731175164Sjhb (uap->flags & O_ACCMODE) != O_RDWR) 732175164Sjhb return (EINVAL); 733175164Sjhb 734261329Srmh if ((uap->flags & ~(O_ACCMODE | O_CREAT | O_EXCL | O_TRUNC | O_CLOEXEC)) != 0) 735175164Sjhb return (EINVAL); 736175164Sjhb 737175164Sjhb fdp = td->td_proc->p_fd; 738175164Sjhb cmode = (uap->mode & ~fdp->fd_cmask) & ACCESSPERMS; 739175164Sjhb 740249233Sjilles error = falloc(td, &fp, &fd, O_CLOEXEC); 741175164Sjhb if (error) 742175164Sjhb return (error); 743175164Sjhb 744175164Sjhb /* A SHM_ANON path pointer creates an anonymous object. */ 745175164Sjhb if (uap->path == SHM_ANON) { 746175164Sjhb /* A read-only anonymous object is pointless. */ 747175164Sjhb if ((uap->flags & O_ACCMODE) == O_RDONLY) { 748321020Sdchagin fdclose(td, fp, fd); 749175164Sjhb fdrop(fp, td); 750175164Sjhb return (EINVAL); 751175164Sjhb } 752175164Sjhb shmfd = shm_alloc(td->td_ucred, cmode); 753175164Sjhb } else { 754175164Sjhb path = malloc(MAXPATHLEN, M_SHMFD, M_WAITOK); 755325783Sjamie pr_path = td->td_ucred->cr_prison->pr_path; 756325783Sjamie 757325783Sjamie /* Construct a full pathname for jailed callers. */ 758325783Sjamie pr_pathlen = strcmp(pr_path, "/") == 0 ? 0 759325783Sjamie : strlcpy(path, pr_path, MAXPATHLEN); 760325783Sjamie error = copyinstr(uap->path, path + pr_pathlen, 761325783Sjamie MAXPATHLEN - pr_pathlen, NULL); 762269742Srpaulo#ifdef KTRACE 763269742Srpaulo if (error == 0 && KTRPOINT(curthread, KTR_NAMEI)) 764269742Srpaulo ktrnamei(path); 765269742Srpaulo#endif 766175164Sjhb /* Require paths to start with a '/' character. */ 767325783Sjamie if (error == 0 && path[pr_pathlen] != '/') 768175164Sjhb error = EINVAL; 769175164Sjhb if (error) { 770321020Sdchagin fdclose(td, fp, fd); 771175164Sjhb fdrop(fp, td); 772175164Sjhb free(path, M_SHMFD); 773175164Sjhb return (error); 774175164Sjhb } 775175164Sjhb 776175164Sjhb fnv = fnv_32_str(path, FNV1_32_INIT); 777175164Sjhb sx_xlock(&shm_dict_lock); 778175164Sjhb shmfd = shm_lookup(path, fnv); 779175164Sjhb if (shmfd == NULL) { 780175164Sjhb /* Object does not yet exist, create it if requested. */ 781175164Sjhb if (uap->flags & O_CREAT) { 782225344Srwatson#ifdef MAC 783225344Srwatson error = mac_posixshm_check_create(td->td_ucred, 784225344Srwatson path); 785225344Srwatson if (error == 0) { 786225344Srwatson#endif 787225344Srwatson shmfd = shm_alloc(td->td_ucred, cmode); 788225344Srwatson shm_insert(path, fnv, shmfd); 789225344Srwatson#ifdef MAC 790225344Srwatson } 791225344Srwatson#endif 792175164Sjhb } else { 793175164Sjhb free(path, M_SHMFD); 794175164Sjhb error = ENOENT; 795175164Sjhb } 796175164Sjhb } else { 797175164Sjhb /* 798175164Sjhb * Object already exists, obtain a new 799175164Sjhb * reference if requested and permitted. 800175164Sjhb */ 801175164Sjhb free(path, M_SHMFD); 802175164Sjhb if ((uap->flags & (O_CREAT | O_EXCL)) == 803175164Sjhb (O_CREAT | O_EXCL)) 804175164Sjhb error = EEXIST; 805175164Sjhb else { 806175164Sjhb#ifdef MAC 807175164Sjhb error = mac_posixshm_check_open(td->td_ucred, 808225344Srwatson shmfd, FFLAGS(uap->flags & O_ACCMODE)); 809175164Sjhb if (error == 0) 810175164Sjhb#endif 811175164Sjhb error = shm_access(shmfd, td->td_ucred, 812175164Sjhb FFLAGS(uap->flags & O_ACCMODE)); 813175164Sjhb } 814175164Sjhb 815175164Sjhb /* 816175164Sjhb * Truncate the file back to zero length if 817175164Sjhb * O_TRUNC was specified and the object was 818175164Sjhb * opened with read/write. 819175164Sjhb */ 820175164Sjhb if (error == 0 && 821175164Sjhb (uap->flags & (O_ACCMODE | O_TRUNC)) == 822175164Sjhb (O_RDWR | O_TRUNC)) { 823175164Sjhb#ifdef MAC 824175164Sjhb error = mac_posixshm_check_truncate( 825175164Sjhb td->td_ucred, fp->f_cred, shmfd); 826175164Sjhb if (error == 0) 827175164Sjhb#endif 828175164Sjhb shm_dotruncate(shmfd, 0); 829175164Sjhb } 830175164Sjhb if (error == 0) 831175164Sjhb shm_hold(shmfd); 832175164Sjhb } 833175164Sjhb sx_xunlock(&shm_dict_lock); 834175164Sjhb 835175164Sjhb if (error) { 836321020Sdchagin fdclose(td, fp, fd); 837175164Sjhb fdrop(fp, td); 838175164Sjhb return (error); 839175164Sjhb } 840175164Sjhb } 841175164Sjhb 842175164Sjhb finit(fp, FFLAGS(uap->flags & O_ACCMODE), DTYPE_SHM, shmfd, &shm_ops); 843175164Sjhb 844175164Sjhb td->td_retval[0] = fd; 845175164Sjhb fdrop(fp, td); 846175164Sjhb 847175164Sjhb return (0); 848175164Sjhb} 849175164Sjhb 850175164Sjhbint 851225617Skmacysys_shm_unlink(struct thread *td, struct shm_unlink_args *uap) 852175164Sjhb{ 853175164Sjhb char *path; 854325783Sjamie const char *pr_path; 855325783Sjamie size_t pr_pathlen; 856175164Sjhb Fnv32_t fnv; 857175164Sjhb int error; 858175164Sjhb 859175164Sjhb path = malloc(MAXPATHLEN, M_TEMP, M_WAITOK); 860325783Sjamie pr_path = td->td_ucred->cr_prison->pr_path; 861325783Sjamie pr_pathlen = strcmp(pr_path, "/") == 0 ? 0 862325783Sjamie : strlcpy(path, pr_path, MAXPATHLEN); 863325783Sjamie error = copyinstr(uap->path, path + pr_pathlen, MAXPATHLEN - pr_pathlen, 864325783Sjamie NULL); 865175164Sjhb if (error) { 866175164Sjhb free(path, M_TEMP); 867175164Sjhb return (error); 868175164Sjhb } 869269742Srpaulo#ifdef KTRACE 870269742Srpaulo if (KTRPOINT(curthread, KTR_NAMEI)) 871269742Srpaulo ktrnamei(path); 872269742Srpaulo#endif 873175164Sjhb fnv = fnv_32_str(path, FNV1_32_INIT); 874175164Sjhb sx_xlock(&shm_dict_lock); 875175164Sjhb error = shm_remove(path, fnv, td->td_ucred); 876175164Sjhb sx_xunlock(&shm_dict_lock); 877175164Sjhb free(path, M_TEMP); 878175164Sjhb 879175164Sjhb return (error); 880175164Sjhb} 881175164Sjhb 882175164Sjhb/* 883175164Sjhb * mmap() helper to validate mmap() requests against shm object state 884175164Sjhb * and give mmap() the vm_object to use for the mapping. 885175164Sjhb */ 886175164Sjhbint 887175164Sjhbshm_mmap(struct shmfd *shmfd, vm_size_t objsize, vm_ooffset_t foff, 888175164Sjhb vm_object_t *obj) 889175164Sjhb{ 890175164Sjhb 891175164Sjhb /* 892175164Sjhb * XXXRW: This validation is probably insufficient, and subject to 893175164Sjhb * sign errors. It should be fixed. 894175164Sjhb */ 895185533Skan if (foff >= shmfd->shm_size || 896185533Skan foff + objsize > round_page(shmfd->shm_size)) 897175164Sjhb return (EINVAL); 898175164Sjhb 899175164Sjhb mtx_lock(&shm_timestamp_lock); 900175164Sjhb vfs_timestamp(&shmfd->shm_atime); 901175164Sjhb mtx_unlock(&shm_timestamp_lock); 902175164Sjhb vm_object_reference(shmfd->shm_object); 903175164Sjhb *obj = shmfd->shm_object; 904175164Sjhb return (0); 905175164Sjhb} 906224914Skib 907224914Skibstatic int 908224914Skibshm_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, 909224914Skib struct thread *td) 910224914Skib{ 911224914Skib struct shmfd *shmfd; 912224914Skib int error; 913224914Skib 914224914Skib error = 0; 915224914Skib shmfd = fp->f_data; 916224914Skib mtx_lock(&shm_timestamp_lock); 917224914Skib /* 918224914Skib * SUSv4 says that x bits of permission need not be affected. 919224914Skib * Be consistent with our shm_open there. 920224914Skib */ 921224914Skib#ifdef MAC 922224914Skib error = mac_posixshm_check_setmode(active_cred, shmfd, mode); 923224914Skib if (error != 0) 924224914Skib goto out; 925224914Skib#endif 926224914Skib error = vaccess(VREG, shmfd->shm_mode, shmfd->shm_uid, 927224914Skib shmfd->shm_gid, VADMIN, active_cred, NULL); 928224914Skib if (error != 0) 929224914Skib goto out; 930224914Skib shmfd->shm_mode = mode & ACCESSPERMS; 931224914Skibout: 932224914Skib mtx_unlock(&shm_timestamp_lock); 933224914Skib return (error); 934224914Skib} 935224914Skib 936224914Skibstatic int 937224914Skibshm_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred, 938224914Skib struct thread *td) 939224914Skib{ 940224914Skib struct shmfd *shmfd; 941224914Skib int error; 942224914Skib 943224935Skib error = 0; 944224914Skib shmfd = fp->f_data; 945224914Skib mtx_lock(&shm_timestamp_lock); 946224914Skib#ifdef MAC 947224914Skib error = mac_posixshm_check_setowner(active_cred, shmfd, uid, gid); 948224914Skib if (error != 0) 949224914Skib goto out; 950224914Skib#endif 951224914Skib if (uid == (uid_t)-1) 952224914Skib uid = shmfd->shm_uid; 953224914Skib if (gid == (gid_t)-1) 954224914Skib gid = shmfd->shm_gid; 955224914Skib if (((uid != shmfd->shm_uid && uid != active_cred->cr_uid) || 956224914Skib (gid != shmfd->shm_gid && !groupmember(gid, active_cred))) && 957224914Skib (error = priv_check_cred(active_cred, PRIV_VFS_CHOWN, 0))) 958224914Skib goto out; 959224914Skib shmfd->shm_uid = uid; 960224914Skib shmfd->shm_gid = gid; 961224914Skibout: 962224914Skib mtx_unlock(&shm_timestamp_lock); 963224914Skib return (error); 964224914Skib} 965228509Sjhb 966228509Sjhb/* 967228509Sjhb * Helper routines to allow the backing object of a shared memory file 968228509Sjhb * descriptor to be mapped in the kernel. 969228509Sjhb */ 970228509Sjhbint 971228509Sjhbshm_map(struct file *fp, size_t size, off_t offset, void **memp) 972228509Sjhb{ 973228509Sjhb struct shmfd *shmfd; 974228509Sjhb vm_offset_t kva, ofs; 975228509Sjhb vm_object_t obj; 976228509Sjhb int rv; 977228509Sjhb 978228509Sjhb if (fp->f_type != DTYPE_SHM) 979228509Sjhb return (EINVAL); 980228509Sjhb shmfd = fp->f_data; 981228509Sjhb obj = shmfd->shm_object; 982248084Sattilio VM_OBJECT_WLOCK(obj); 983228509Sjhb /* 984228509Sjhb * XXXRW: This validation is probably insufficient, and subject to 985228509Sjhb * sign errors. It should be fixed. 986228509Sjhb */ 987228509Sjhb if (offset >= shmfd->shm_size || 988228509Sjhb offset + size > round_page(shmfd->shm_size)) { 989248084Sattilio VM_OBJECT_WUNLOCK(obj); 990228509Sjhb return (EINVAL); 991228509Sjhb } 992228509Sjhb 993228509Sjhb shmfd->shm_kmappings++; 994228509Sjhb vm_object_reference_locked(obj); 995248084Sattilio VM_OBJECT_WUNLOCK(obj); 996228509Sjhb 997228509Sjhb /* Map the object into the kernel_map and wire it. */ 998228509Sjhb kva = vm_map_min(kernel_map); 999228509Sjhb ofs = offset & PAGE_MASK; 1000228509Sjhb offset = trunc_page(offset); 1001228509Sjhb size = round_page(size + ofs); 1002255426Sjhb rv = vm_map_find(kernel_map, obj, offset, &kva, size, 0, 1003253620Sjhb VMFS_OPTIMAL_SPACE, VM_PROT_READ | VM_PROT_WRITE, 1004228509Sjhb VM_PROT_READ | VM_PROT_WRITE, 0); 1005228509Sjhb if (rv == KERN_SUCCESS) { 1006228509Sjhb rv = vm_map_wire(kernel_map, kva, kva + size, 1007228509Sjhb VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES); 1008228509Sjhb if (rv == KERN_SUCCESS) { 1009228509Sjhb *memp = (void *)(kva + ofs); 1010228509Sjhb return (0); 1011228509Sjhb } 1012228509Sjhb vm_map_remove(kernel_map, kva, kva + size); 1013228509Sjhb } else 1014228509Sjhb vm_object_deallocate(obj); 1015228509Sjhb 1016228509Sjhb /* On failure, drop our mapping reference. */ 1017248084Sattilio VM_OBJECT_WLOCK(obj); 1018228509Sjhb shmfd->shm_kmappings--; 1019248084Sattilio VM_OBJECT_WUNLOCK(obj); 1020228509Sjhb 1021228533Sjhb return (vm_mmap_to_errno(rv)); 1022228509Sjhb} 1023228509Sjhb 1024228509Sjhb/* 1025228509Sjhb * We require the caller to unmap the entire entry. This allows us to 1026228509Sjhb * safely decrement shm_kmappings when a mapping is removed. 1027228509Sjhb */ 1028228509Sjhbint 1029228509Sjhbshm_unmap(struct file *fp, void *mem, size_t size) 1030228509Sjhb{ 1031228509Sjhb struct shmfd *shmfd; 1032228509Sjhb vm_map_entry_t entry; 1033228509Sjhb vm_offset_t kva, ofs; 1034228509Sjhb vm_object_t obj; 1035228509Sjhb vm_pindex_t pindex; 1036228509Sjhb vm_prot_t prot; 1037228509Sjhb boolean_t wired; 1038228509Sjhb vm_map_t map; 1039228509Sjhb int rv; 1040228509Sjhb 1041228509Sjhb if (fp->f_type != DTYPE_SHM) 1042228509Sjhb return (EINVAL); 1043228509Sjhb shmfd = fp->f_data; 1044228509Sjhb kva = (vm_offset_t)mem; 1045228509Sjhb ofs = kva & PAGE_MASK; 1046228509Sjhb kva = trunc_page(kva); 1047228509Sjhb size = round_page(size + ofs); 1048228509Sjhb map = kernel_map; 1049228509Sjhb rv = vm_map_lookup(&map, kva, VM_PROT_READ | VM_PROT_WRITE, &entry, 1050228509Sjhb &obj, &pindex, &prot, &wired); 1051228509Sjhb if (rv != KERN_SUCCESS) 1052228509Sjhb return (EINVAL); 1053228509Sjhb if (entry->start != kva || entry->end != kva + size) { 1054228509Sjhb vm_map_lookup_done(map, entry); 1055228509Sjhb return (EINVAL); 1056228509Sjhb } 1057228509Sjhb vm_map_lookup_done(map, entry); 1058228509Sjhb if (obj != shmfd->shm_object) 1059228509Sjhb return (EINVAL); 1060228509Sjhb vm_map_remove(map, kva, kva + size); 1061248084Sattilio VM_OBJECT_WLOCK(obj); 1062228509Sjhb KASSERT(shmfd->shm_kmappings > 0, ("shm_unmap: object not mapped")); 1063228509Sjhb shmfd->shm_kmappings--; 1064248084Sattilio VM_OBJECT_WUNLOCK(obj); 1065228509Sjhb return (0); 1066228509Sjhb} 1067233760Sjhb 1068233760Sjhbvoid 1069233760Sjhbshm_path(struct shmfd *shmfd, char *path, size_t size) 1070233760Sjhb{ 1071325783Sjamie const char *shm_path, *pr_path; 1072325783Sjamie size_t pr_pathlen; 1073233760Sjhb 1074233760Sjhb if (shmfd->shm_path == NULL) 1075233760Sjhb return; 1076233760Sjhb sx_slock(&shm_dict_lock); 1077325783Sjamie shm_path = shmfd->shm_path; 1078325783Sjamie if (shm_path != NULL) { 1079325783Sjamie pr_path = curthread->td_ucred->cr_prison->pr_path; 1080325783Sjamie if (strcmp(pr_path, "/") != 0) { 1081325783Sjamie /* Return the jail-rooted pathname. */ 1082325783Sjamie pr_pathlen = strlen(pr_path); 1083325783Sjamie if (strncmp(shm_path, pr_path, pr_pathlen) == 0 && 1084325783Sjamie shm_path[pr_pathlen] == '/') 1085325783Sjamie shm_path += pr_pathlen; 1086325783Sjamie } 1087325783Sjamie strlcpy(path, shm_path, size); 1088325783Sjamie } 1089233760Sjhb sx_sunlock(&shm_dict_lock); 1090233760Sjhb} 1091