uipc_shm.c revision 225344
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 * 43225344Srwatson * (4) 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? 49175164Sjhb */ 50175164Sjhb 51175164Sjhb#include <sys/cdefs.h> 52175164Sjhb__FBSDID("$FreeBSD: head/sys/kern/uipc_shm.c 225344 2011-09-02 17:40:39Z rwatson $"); 53175164Sjhb 54223692Sjonathan#include "opt_capsicum.h" 55223692Sjonathan 56175164Sjhb#include <sys/param.h> 57223692Sjonathan#include <sys/capability.h> 58175164Sjhb#include <sys/fcntl.h> 59175164Sjhb#include <sys/file.h> 60175164Sjhb#include <sys/filedesc.h> 61175164Sjhb#include <sys/fnv_hash.h> 62175164Sjhb#include <sys/kernel.h> 63175164Sjhb#include <sys/lock.h> 64175164Sjhb#include <sys/malloc.h> 65175164Sjhb#include <sys/mman.h> 66175164Sjhb#include <sys/mutex.h> 67224914Skib#include <sys/priv.h> 68175164Sjhb#include <sys/proc.h> 69175164Sjhb#include <sys/refcount.h> 70175164Sjhb#include <sys/resourcevar.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> 78175164Sjhb 79175164Sjhb#include <security/mac/mac_framework.h> 80175164Sjhb 81175164Sjhb#include <vm/vm.h> 82175164Sjhb#include <vm/vm_param.h> 83175164Sjhb#include <vm/pmap.h> 84175164Sjhb#include <vm/vm_map.h> 85175164Sjhb#include <vm/vm_object.h> 86175164Sjhb#include <vm/vm_page.h> 87175164Sjhb#include <vm/vm_pager.h> 88175164Sjhb#include <vm/swap_pager.h> 89175164Sjhb 90175164Sjhbstruct shm_mapping { 91175164Sjhb char *sm_path; 92175164Sjhb Fnv32_t sm_fnv; 93175164Sjhb struct shmfd *sm_shmfd; 94175164Sjhb LIST_ENTRY(shm_mapping) sm_link; 95175164Sjhb}; 96175164Sjhb 97175164Sjhbstatic MALLOC_DEFINE(M_SHMFD, "shmfd", "shared memory file descriptor"); 98175164Sjhbstatic LIST_HEAD(, shm_mapping) *shm_dictionary; 99175164Sjhbstatic struct sx shm_dict_lock; 100175164Sjhbstatic struct mtx shm_timestamp_lock; 101175164Sjhbstatic u_long shm_hash; 102175164Sjhb 103175164Sjhb#define SHM_HASH(fnv) (&shm_dictionary[(fnv) & shm_hash]) 104175164Sjhb 105175164Sjhbstatic int shm_access(struct shmfd *shmfd, struct ucred *ucred, int flags); 106175164Sjhbstatic struct shmfd *shm_alloc(struct ucred *ucred, mode_t mode); 107175164Sjhbstatic void shm_dict_init(void *arg); 108175164Sjhbstatic void shm_drop(struct shmfd *shmfd); 109175164Sjhbstatic struct shmfd *shm_hold(struct shmfd *shmfd); 110175164Sjhbstatic void shm_insert(char *path, Fnv32_t fnv, struct shmfd *shmfd); 111175164Sjhbstatic struct shmfd *shm_lookup(char *path, Fnv32_t fnv); 112175164Sjhbstatic int shm_remove(char *path, Fnv32_t fnv, struct ucred *ucred); 113194766Skibstatic int shm_dotruncate(struct shmfd *shmfd, off_t length); 114175164Sjhb 115175164Sjhbstatic fo_rdwr_t shm_read; 116175164Sjhbstatic fo_rdwr_t shm_write; 117175164Sjhbstatic fo_truncate_t shm_truncate; 118175164Sjhbstatic fo_ioctl_t shm_ioctl; 119175164Sjhbstatic fo_poll_t shm_poll; 120175164Sjhbstatic fo_kqfilter_t shm_kqfilter; 121175164Sjhbstatic fo_stat_t shm_stat; 122175164Sjhbstatic fo_close_t shm_close; 123224914Skibstatic fo_chmod_t shm_chmod; 124224914Skibstatic fo_chown_t shm_chown; 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, 136224914Skib .fo_chmod = shm_chmod, 137224914Skib .fo_chown = shm_chown, 138175164Sjhb .fo_flags = DFLAG_PASSABLE 139175164Sjhb}; 140175164Sjhb 141175164SjhbFEATURE(posix_shm, "POSIX shared memory"); 142175164Sjhb 143175164Sjhbstatic int 144175164Sjhbshm_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 145175164Sjhb int flags, struct thread *td) 146175164Sjhb{ 147175164Sjhb 148175164Sjhb return (EOPNOTSUPP); 149175164Sjhb} 150175164Sjhb 151175164Sjhbstatic int 152175164Sjhbshm_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 153175164Sjhb int flags, struct thread *td) 154175164Sjhb{ 155175164Sjhb 156175164Sjhb return (EOPNOTSUPP); 157175164Sjhb} 158175164Sjhb 159175164Sjhbstatic int 160175164Sjhbshm_truncate(struct file *fp, off_t length, struct ucred *active_cred, 161175164Sjhb struct thread *td) 162175164Sjhb{ 163175164Sjhb struct shmfd *shmfd; 164175164Sjhb#ifdef MAC 165175164Sjhb int error; 166175164Sjhb#endif 167175164Sjhb 168175164Sjhb shmfd = fp->f_data; 169175164Sjhb#ifdef MAC 170175164Sjhb error = mac_posixshm_check_truncate(active_cred, fp->f_cred, shmfd); 171175164Sjhb if (error) 172175164Sjhb return (error); 173175164Sjhb#endif 174194766Skib return (shm_dotruncate(shmfd, length)); 175175164Sjhb} 176175164Sjhb 177175164Sjhbstatic int 178175164Sjhbshm_ioctl(struct file *fp, u_long com, void *data, 179175164Sjhb struct ucred *active_cred, struct thread *td) 180175164Sjhb{ 181175164Sjhb 182175164Sjhb return (EOPNOTSUPP); 183175164Sjhb} 184175164Sjhb 185175164Sjhbstatic int 186175164Sjhbshm_poll(struct file *fp, int events, struct ucred *active_cred, 187175164Sjhb struct thread *td) 188175164Sjhb{ 189175164Sjhb 190175164Sjhb return (EOPNOTSUPP); 191175164Sjhb} 192175164Sjhb 193175164Sjhbstatic int 194175164Sjhbshm_kqfilter(struct file *fp, struct knote *kn) 195175164Sjhb{ 196175164Sjhb 197175164Sjhb return (EOPNOTSUPP); 198175164Sjhb} 199175164Sjhb 200175164Sjhbstatic int 201175164Sjhbshm_stat(struct file *fp, struct stat *sb, struct ucred *active_cred, 202175164Sjhb struct thread *td) 203175164Sjhb{ 204175164Sjhb struct shmfd *shmfd; 205175164Sjhb#ifdef MAC 206175164Sjhb int error; 207175164Sjhb#endif 208175164Sjhb 209175164Sjhb shmfd = fp->f_data; 210175164Sjhb 211175164Sjhb#ifdef MAC 212175164Sjhb error = mac_posixshm_check_stat(active_cred, fp->f_cred, shmfd); 213175164Sjhb if (error) 214175164Sjhb return (error); 215175164Sjhb#endif 216175164Sjhb 217175164Sjhb /* 218175164Sjhb * Attempt to return sanish values for fstat() on a memory file 219175164Sjhb * descriptor. 220175164Sjhb */ 221175164Sjhb bzero(sb, sizeof(*sb)); 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; 225224914Skib mtx_lock(&shm_timestamp_lock); 226205792Sed sb->st_atim = shmfd->shm_atime; 227205792Sed sb->st_ctim = shmfd->shm_ctime; 228205792Sed sb->st_mtim = shmfd->shm_mtime; 229224914Skib sb->st_birthtim = shmfd->shm_birthtime; 230224914Skib sb->st_mode = S_IFREG | shmfd->shm_mode; /* XXX */ 231175164Sjhb sb->st_uid = shmfd->shm_uid; 232175164Sjhb sb->st_gid = shmfd->shm_gid; 233224914Skib mtx_unlock(&shm_timestamp_lock); 234175164Sjhb 235175164Sjhb return (0); 236175164Sjhb} 237175164Sjhb 238175164Sjhbstatic int 239175164Sjhbshm_close(struct file *fp, struct thread *td) 240175164Sjhb{ 241175164Sjhb struct shmfd *shmfd; 242175164Sjhb 243175164Sjhb shmfd = fp->f_data; 244175164Sjhb fp->f_data = NULL; 245175164Sjhb shm_drop(shmfd); 246175164Sjhb 247175164Sjhb return (0); 248175164Sjhb} 249175164Sjhb 250194766Skibstatic int 251175164Sjhbshm_dotruncate(struct shmfd *shmfd, off_t length) 252175164Sjhb{ 253175164Sjhb vm_object_t object; 254175164Sjhb vm_page_t m; 255175164Sjhb vm_pindex_t nobjsize; 256194766Skib vm_ooffset_t delta; 257175164Sjhb 258175164Sjhb object = shmfd->shm_object; 259175164Sjhb VM_OBJECT_LOCK(object); 260175164Sjhb if (length == shmfd->shm_size) { 261175164Sjhb VM_OBJECT_UNLOCK(object); 262194766Skib return (0); 263175164Sjhb } 264175164Sjhb nobjsize = OFF_TO_IDX(length + PAGE_MASK); 265175164Sjhb 266175164Sjhb /* Are we shrinking? If so, trim the end. */ 267175164Sjhb if (length < shmfd->shm_size) { 268194766Skib delta = ptoa(object->size - nobjsize); 269194766Skib 270175164Sjhb /* Toss in memory pages. */ 271175164Sjhb if (nobjsize < object->size) 272175164Sjhb vm_object_page_remove(object, nobjsize, object->size, 273223677Salc 0); 274175164Sjhb 275175164Sjhb /* Toss pages from swap. */ 276175164Sjhb if (object->type == OBJT_SWAP) 277194766Skib swap_pager_freespace(object, nobjsize, delta); 278175164Sjhb 279194766Skib /* Free the swap accounted for shm */ 280216128Strasz swap_release_by_cred(delta, object->cred); 281194766Skib object->charge -= delta; 282194766Skib 283175164Sjhb /* 284175164Sjhb * If the last page is partially mapped, then zero out 285175164Sjhb * the garbage at the end of the page. See comments 286193303Salc * in vnode_pager_setsize() for more details. 287175164Sjhb * 288175164Sjhb * XXXJHB: This handles in memory pages, but what about 289175164Sjhb * a page swapped out to disk? 290175164Sjhb */ 291175164Sjhb if ((length & PAGE_MASK) && 292175164Sjhb (m = vm_page_lookup(object, OFF_TO_IDX(length))) != NULL && 293175164Sjhb m->valid != 0) { 294175164Sjhb int base = (int)length & PAGE_MASK; 295175164Sjhb int size = PAGE_SIZE - base; 296175164Sjhb 297175164Sjhb pmap_zero_page_area(m, base, size); 298193303Salc 299193303Salc /* 300193303Salc * Update the valid bits to reflect the blocks that 301193303Salc * have been zeroed. Some of these valid bits may 302193303Salc * have already been set. 303193303Salc */ 304193303Salc vm_page_set_valid(m, base, size); 305193303Salc 306193303Salc /* 307193303Salc * Round "base" to the next block boundary so that the 308193303Salc * dirty bit for a partially zeroed block is not 309193303Salc * cleared. 310193303Salc */ 311193303Salc base = roundup2(base, DEV_BSIZE); 312193303Salc 313193303Salc vm_page_clear_dirty(m, base, PAGE_SIZE - base); 314176075Salc } else if ((length & PAGE_MASK) && 315176075Salc __predict_false(object->cache != NULL)) { 316176075Salc vm_page_cache_free(object, OFF_TO_IDX(length), 317176075Salc nobjsize); 318175164Sjhb } 319194766Skib } else { 320194766Skib 321194766Skib /* Attempt to reserve the swap */ 322194766Skib delta = ptoa(nobjsize - object->size); 323216128Strasz if (!swap_reserve_by_cred(delta, object->cred)) { 324194766Skib VM_OBJECT_UNLOCK(object); 325194766Skib return (ENOMEM); 326194766Skib } 327194766Skib object->charge += delta; 328175164Sjhb } 329175164Sjhb shmfd->shm_size = length; 330175164Sjhb mtx_lock(&shm_timestamp_lock); 331175164Sjhb vfs_timestamp(&shmfd->shm_ctime); 332175164Sjhb shmfd->shm_mtime = shmfd->shm_ctime; 333175164Sjhb mtx_unlock(&shm_timestamp_lock); 334175164Sjhb object->size = nobjsize; 335175164Sjhb VM_OBJECT_UNLOCK(object); 336194766Skib return (0); 337175164Sjhb} 338175164Sjhb 339175164Sjhb/* 340175164Sjhb * shmfd object management including creation and reference counting 341175164Sjhb * routines. 342175164Sjhb */ 343175164Sjhbstatic struct shmfd * 344175164Sjhbshm_alloc(struct ucred *ucred, mode_t mode) 345175164Sjhb{ 346175164Sjhb struct shmfd *shmfd; 347175164Sjhb 348175164Sjhb shmfd = malloc(sizeof(*shmfd), M_SHMFD, M_WAITOK | M_ZERO); 349175164Sjhb shmfd->shm_size = 0; 350175164Sjhb shmfd->shm_uid = ucred->cr_uid; 351175164Sjhb shmfd->shm_gid = ucred->cr_gid; 352175164Sjhb shmfd->shm_mode = mode; 353175164Sjhb shmfd->shm_object = vm_pager_allocate(OBJT_DEFAULT, NULL, 354194766Skib shmfd->shm_size, VM_PROT_DEFAULT, 0, ucred); 355175164Sjhb KASSERT(shmfd->shm_object != NULL, ("shm_create: vm_pager_allocate")); 356178181Salc VM_OBJECT_LOCK(shmfd->shm_object); 357178181Salc vm_object_clear_flag(shmfd->shm_object, OBJ_ONEMAPPING); 358178181Salc vm_object_set_flag(shmfd->shm_object, OBJ_NOSPLIT); 359178181Salc VM_OBJECT_UNLOCK(shmfd->shm_object); 360175164Sjhb vfs_timestamp(&shmfd->shm_birthtime); 361175164Sjhb shmfd->shm_atime = shmfd->shm_mtime = shmfd->shm_ctime = 362175164Sjhb shmfd->shm_birthtime; 363175164Sjhb refcount_init(&shmfd->shm_refs, 1); 364175164Sjhb#ifdef MAC 365175164Sjhb mac_posixshm_init(shmfd); 366175164Sjhb mac_posixshm_create(ucred, shmfd); 367175164Sjhb#endif 368175164Sjhb 369175164Sjhb return (shmfd); 370175164Sjhb} 371175164Sjhb 372175164Sjhbstatic struct shmfd * 373175164Sjhbshm_hold(struct shmfd *shmfd) 374175164Sjhb{ 375175164Sjhb 376175164Sjhb refcount_acquire(&shmfd->shm_refs); 377175164Sjhb return (shmfd); 378175164Sjhb} 379175164Sjhb 380175164Sjhbstatic void 381175164Sjhbshm_drop(struct shmfd *shmfd) 382175164Sjhb{ 383175164Sjhb 384175164Sjhb if (refcount_release(&shmfd->shm_refs)) { 385175164Sjhb#ifdef MAC 386175164Sjhb mac_posixshm_destroy(shmfd); 387175164Sjhb#endif 388175164Sjhb vm_object_deallocate(shmfd->shm_object); 389175164Sjhb free(shmfd, M_SHMFD); 390175164Sjhb } 391175164Sjhb} 392175164Sjhb 393175164Sjhb/* 394175164Sjhb * Determine if the credentials have sufficient permissions for a 395175164Sjhb * specified combination of FREAD and FWRITE. 396175164Sjhb */ 397175164Sjhbstatic int 398175164Sjhbshm_access(struct shmfd *shmfd, struct ucred *ucred, int flags) 399175164Sjhb{ 400184413Strasz accmode_t accmode; 401224914Skib int error; 402175164Sjhb 403184413Strasz accmode = 0; 404175164Sjhb if (flags & FREAD) 405184413Strasz accmode |= VREAD; 406175164Sjhb if (flags & FWRITE) 407184413Strasz accmode |= VWRITE; 408224914Skib mtx_lock(&shm_timestamp_lock); 409224914Skib error = vaccess(VREG, shmfd->shm_mode, shmfd->shm_uid, shmfd->shm_gid, 410224914Skib accmode, ucred, NULL); 411224914Skib mtx_unlock(&shm_timestamp_lock); 412224914Skib return (error); 413175164Sjhb} 414175164Sjhb 415175164Sjhb/* 416175164Sjhb * Dictionary management. We maintain an in-kernel dictionary to map 417175164Sjhb * paths to shmfd objects. We use the FNV hash on the path to store 418175164Sjhb * the mappings in a hash table. 419175164Sjhb */ 420175164Sjhbstatic void 421175164Sjhbshm_dict_init(void *arg) 422175164Sjhb{ 423175164Sjhb 424175164Sjhb mtx_init(&shm_timestamp_lock, "shm timestamps", NULL, MTX_DEF); 425175164Sjhb sx_init(&shm_dict_lock, "shm dictionary"); 426175164Sjhb shm_dictionary = hashinit(1024, M_SHMFD, &shm_hash); 427175164Sjhb} 428175164SjhbSYSINIT(shm_dict_init, SI_SUB_SYSV_SHM, SI_ORDER_ANY, shm_dict_init, NULL); 429175164Sjhb 430175164Sjhbstatic struct shmfd * 431175164Sjhbshm_lookup(char *path, Fnv32_t fnv) 432175164Sjhb{ 433175164Sjhb struct shm_mapping *map; 434175164Sjhb 435175164Sjhb LIST_FOREACH(map, SHM_HASH(fnv), sm_link) { 436175164Sjhb if (map->sm_fnv != fnv) 437175164Sjhb continue; 438175164Sjhb if (strcmp(map->sm_path, path) == 0) 439175164Sjhb return (map->sm_shmfd); 440175164Sjhb } 441175164Sjhb 442175164Sjhb return (NULL); 443175164Sjhb} 444175164Sjhb 445175164Sjhbstatic void 446175164Sjhbshm_insert(char *path, Fnv32_t fnv, struct shmfd *shmfd) 447175164Sjhb{ 448175164Sjhb struct shm_mapping *map; 449175164Sjhb 450175164Sjhb map = malloc(sizeof(struct shm_mapping), M_SHMFD, M_WAITOK); 451175164Sjhb map->sm_path = path; 452175164Sjhb map->sm_fnv = fnv; 453175164Sjhb map->sm_shmfd = shm_hold(shmfd); 454175164Sjhb LIST_INSERT_HEAD(SHM_HASH(fnv), map, sm_link); 455175164Sjhb} 456175164Sjhb 457175164Sjhbstatic int 458175164Sjhbshm_remove(char *path, Fnv32_t fnv, struct ucred *ucred) 459175164Sjhb{ 460175164Sjhb struct shm_mapping *map; 461175164Sjhb int error; 462175164Sjhb 463175164Sjhb LIST_FOREACH(map, SHM_HASH(fnv), sm_link) { 464175164Sjhb if (map->sm_fnv != fnv) 465175164Sjhb continue; 466175164Sjhb if (strcmp(map->sm_path, path) == 0) { 467175164Sjhb#ifdef MAC 468175164Sjhb error = mac_posixshm_check_unlink(ucred, map->sm_shmfd); 469175164Sjhb if (error) 470175164Sjhb return (error); 471175164Sjhb#endif 472175164Sjhb error = shm_access(map->sm_shmfd, ucred, 473175164Sjhb FREAD | FWRITE); 474175164Sjhb if (error) 475175164Sjhb return (error); 476175164Sjhb LIST_REMOVE(map, sm_link); 477175164Sjhb shm_drop(map->sm_shmfd); 478175164Sjhb free(map->sm_path, M_SHMFD); 479175164Sjhb free(map, M_SHMFD); 480175164Sjhb return (0); 481175164Sjhb } 482175164Sjhb } 483175164Sjhb 484175164Sjhb return (ENOENT); 485175164Sjhb} 486175164Sjhb 487175164Sjhb/* System calls. */ 488175164Sjhbint 489175164Sjhbshm_open(struct thread *td, struct shm_open_args *uap) 490175164Sjhb{ 491175164Sjhb struct filedesc *fdp; 492175164Sjhb struct shmfd *shmfd; 493175164Sjhb struct file *fp; 494175164Sjhb char *path; 495175164Sjhb Fnv32_t fnv; 496175164Sjhb mode_t cmode; 497175164Sjhb int fd, error; 498175164Sjhb 499223692Sjonathan#ifdef CAPABILITY_MODE 500223692Sjonathan /* 501223692Sjonathan * shm_open(2) is only allowed for anonymous objects. 502223692Sjonathan */ 503223692Sjonathan if (IN_CAPABILITY_MODE(td) && (uap->path != SHM_ANON)) 504223692Sjonathan return (ECAPMODE); 505223692Sjonathan#endif 506223692Sjonathan 507175164Sjhb if ((uap->flags & O_ACCMODE) != O_RDONLY && 508175164Sjhb (uap->flags & O_ACCMODE) != O_RDWR) 509175164Sjhb return (EINVAL); 510175164Sjhb 511175164Sjhb if ((uap->flags & ~(O_ACCMODE | O_CREAT | O_EXCL | O_TRUNC)) != 0) 512175164Sjhb return (EINVAL); 513175164Sjhb 514175164Sjhb fdp = td->td_proc->p_fd; 515175164Sjhb cmode = (uap->mode & ~fdp->fd_cmask) & ACCESSPERMS; 516175164Sjhb 517220245Skib error = falloc(td, &fp, &fd, 0); 518175164Sjhb if (error) 519175164Sjhb return (error); 520175164Sjhb 521175164Sjhb /* A SHM_ANON path pointer creates an anonymous object. */ 522175164Sjhb if (uap->path == SHM_ANON) { 523175164Sjhb /* A read-only anonymous object is pointless. */ 524175164Sjhb if ((uap->flags & O_ACCMODE) == O_RDONLY) { 525175164Sjhb fdclose(fdp, fp, fd, td); 526175164Sjhb fdrop(fp, td); 527175164Sjhb return (EINVAL); 528175164Sjhb } 529175164Sjhb shmfd = shm_alloc(td->td_ucred, cmode); 530175164Sjhb } else { 531175164Sjhb path = malloc(MAXPATHLEN, M_SHMFD, M_WAITOK); 532175164Sjhb error = copyinstr(uap->path, path, MAXPATHLEN, NULL); 533175164Sjhb 534175164Sjhb /* Require paths to start with a '/' character. */ 535175164Sjhb if (error == 0 && path[0] != '/') 536175164Sjhb error = EINVAL; 537175164Sjhb if (error) { 538175164Sjhb fdclose(fdp, fp, fd, td); 539175164Sjhb fdrop(fp, td); 540175164Sjhb free(path, M_SHMFD); 541175164Sjhb return (error); 542175164Sjhb } 543175164Sjhb 544175164Sjhb fnv = fnv_32_str(path, FNV1_32_INIT); 545175164Sjhb sx_xlock(&shm_dict_lock); 546175164Sjhb shmfd = shm_lookup(path, fnv); 547175164Sjhb if (shmfd == NULL) { 548175164Sjhb /* Object does not yet exist, create it if requested. */ 549175164Sjhb if (uap->flags & O_CREAT) { 550225344Srwatson#ifdef MAC 551225344Srwatson error = mac_posixshm_check_create(td->td_ucred, 552225344Srwatson path); 553225344Srwatson if (error == 0) { 554225344Srwatson#endif 555225344Srwatson shmfd = shm_alloc(td->td_ucred, cmode); 556225344Srwatson shm_insert(path, fnv, shmfd); 557225344Srwatson#ifdef MAC 558225344Srwatson } 559225344Srwatson#endif 560175164Sjhb } else { 561175164Sjhb free(path, M_SHMFD); 562175164Sjhb error = ENOENT; 563175164Sjhb } 564175164Sjhb } else { 565175164Sjhb /* 566175164Sjhb * Object already exists, obtain a new 567175164Sjhb * reference if requested and permitted. 568175164Sjhb */ 569175164Sjhb free(path, M_SHMFD); 570175164Sjhb if ((uap->flags & (O_CREAT | O_EXCL)) == 571175164Sjhb (O_CREAT | O_EXCL)) 572175164Sjhb error = EEXIST; 573175164Sjhb else { 574175164Sjhb#ifdef MAC 575175164Sjhb error = mac_posixshm_check_open(td->td_ucred, 576225344Srwatson shmfd, FFLAGS(uap->flags & O_ACCMODE)); 577175164Sjhb if (error == 0) 578175164Sjhb#endif 579175164Sjhb error = shm_access(shmfd, td->td_ucred, 580175164Sjhb FFLAGS(uap->flags & O_ACCMODE)); 581175164Sjhb } 582175164Sjhb 583175164Sjhb /* 584175164Sjhb * Truncate the file back to zero length if 585175164Sjhb * O_TRUNC was specified and the object was 586175164Sjhb * opened with read/write. 587175164Sjhb */ 588175164Sjhb if (error == 0 && 589175164Sjhb (uap->flags & (O_ACCMODE | O_TRUNC)) == 590175164Sjhb (O_RDWR | O_TRUNC)) { 591175164Sjhb#ifdef MAC 592175164Sjhb error = mac_posixshm_check_truncate( 593175164Sjhb td->td_ucred, fp->f_cred, shmfd); 594175164Sjhb if (error == 0) 595175164Sjhb#endif 596175164Sjhb shm_dotruncate(shmfd, 0); 597175164Sjhb } 598175164Sjhb if (error == 0) 599175164Sjhb shm_hold(shmfd); 600175164Sjhb } 601175164Sjhb sx_xunlock(&shm_dict_lock); 602175164Sjhb 603175164Sjhb if (error) { 604175164Sjhb fdclose(fdp, fp, fd, td); 605175164Sjhb fdrop(fp, td); 606175164Sjhb return (error); 607175164Sjhb } 608175164Sjhb } 609175164Sjhb 610175164Sjhb finit(fp, FFLAGS(uap->flags & O_ACCMODE), DTYPE_SHM, shmfd, &shm_ops); 611175164Sjhb 612175164Sjhb FILEDESC_XLOCK(fdp); 613175164Sjhb if (fdp->fd_ofiles[fd] == fp) 614175164Sjhb fdp->fd_ofileflags[fd] |= UF_EXCLOSE; 615175164Sjhb FILEDESC_XUNLOCK(fdp); 616175164Sjhb td->td_retval[0] = fd; 617175164Sjhb fdrop(fp, td); 618175164Sjhb 619175164Sjhb return (0); 620175164Sjhb} 621175164Sjhb 622175164Sjhbint 623175164Sjhbshm_unlink(struct thread *td, struct shm_unlink_args *uap) 624175164Sjhb{ 625175164Sjhb char *path; 626175164Sjhb Fnv32_t fnv; 627175164Sjhb int error; 628175164Sjhb 629175164Sjhb path = malloc(MAXPATHLEN, M_TEMP, M_WAITOK); 630175164Sjhb error = copyinstr(uap->path, path, MAXPATHLEN, NULL); 631175164Sjhb if (error) { 632175164Sjhb free(path, M_TEMP); 633175164Sjhb return (error); 634175164Sjhb } 635175164Sjhb 636175164Sjhb fnv = fnv_32_str(path, FNV1_32_INIT); 637175164Sjhb sx_xlock(&shm_dict_lock); 638175164Sjhb error = shm_remove(path, fnv, td->td_ucred); 639175164Sjhb sx_xunlock(&shm_dict_lock); 640175164Sjhb free(path, M_TEMP); 641175164Sjhb 642175164Sjhb return (error); 643175164Sjhb} 644175164Sjhb 645175164Sjhb/* 646175164Sjhb * mmap() helper to validate mmap() requests against shm object state 647175164Sjhb * and give mmap() the vm_object to use for the mapping. 648175164Sjhb */ 649175164Sjhbint 650175164Sjhbshm_mmap(struct shmfd *shmfd, vm_size_t objsize, vm_ooffset_t foff, 651175164Sjhb vm_object_t *obj) 652175164Sjhb{ 653175164Sjhb 654175164Sjhb /* 655175164Sjhb * XXXRW: This validation is probably insufficient, and subject to 656175164Sjhb * sign errors. It should be fixed. 657175164Sjhb */ 658185533Skan if (foff >= shmfd->shm_size || 659185533Skan foff + objsize > round_page(shmfd->shm_size)) 660175164Sjhb return (EINVAL); 661175164Sjhb 662175164Sjhb mtx_lock(&shm_timestamp_lock); 663175164Sjhb vfs_timestamp(&shmfd->shm_atime); 664175164Sjhb mtx_unlock(&shm_timestamp_lock); 665175164Sjhb vm_object_reference(shmfd->shm_object); 666175164Sjhb *obj = shmfd->shm_object; 667175164Sjhb return (0); 668175164Sjhb} 669224914Skib 670224914Skibstatic int 671224914Skibshm_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, 672224914Skib struct thread *td) 673224914Skib{ 674224914Skib struct shmfd *shmfd; 675224914Skib int error; 676224914Skib 677224914Skib error = 0; 678224914Skib shmfd = fp->f_data; 679224914Skib mtx_lock(&shm_timestamp_lock); 680224914Skib /* 681224914Skib * SUSv4 says that x bits of permission need not be affected. 682224914Skib * Be consistent with our shm_open there. 683224914Skib */ 684224914Skib#ifdef MAC 685224914Skib error = mac_posixshm_check_setmode(active_cred, shmfd, mode); 686224914Skib if (error != 0) 687224914Skib goto out; 688224914Skib#endif 689224914Skib error = vaccess(VREG, shmfd->shm_mode, shmfd->shm_uid, 690224914Skib shmfd->shm_gid, VADMIN, active_cred, NULL); 691224914Skib if (error != 0) 692224914Skib goto out; 693224914Skib shmfd->shm_mode = mode & ACCESSPERMS; 694224914Skibout: 695224914Skib mtx_unlock(&shm_timestamp_lock); 696224914Skib return (error); 697224914Skib} 698224914Skib 699224914Skibstatic int 700224914Skibshm_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred, 701224914Skib struct thread *td) 702224914Skib{ 703224914Skib struct shmfd *shmfd; 704224914Skib int error; 705224914Skib 706224935Skib error = 0; 707224914Skib shmfd = fp->f_data; 708224914Skib mtx_lock(&shm_timestamp_lock); 709224914Skib#ifdef MAC 710224914Skib error = mac_posixshm_check_setowner(active_cred, shmfd, uid, gid); 711224914Skib if (error != 0) 712224914Skib goto out; 713224914Skib#endif 714224914Skib if (uid == (uid_t)-1) 715224914Skib uid = shmfd->shm_uid; 716224914Skib if (gid == (gid_t)-1) 717224914Skib gid = shmfd->shm_gid; 718224914Skib if (((uid != shmfd->shm_uid && uid != active_cred->cr_uid) || 719224914Skib (gid != shmfd->shm_gid && !groupmember(gid, active_cred))) && 720224914Skib (error = priv_check_cred(active_cred, PRIV_VFS_CHOWN, 0))) 721224914Skib goto out; 722224914Skib shmfd->shm_uid = uid; 723224914Skib shmfd->shm_gid = gid; 724224914Skibout: 725224914Skib mtx_unlock(&shm_timestamp_lock); 726224914Skib return (error); 727224914Skib} 728