| 1 | /* |
| 2 | * Copyright (c) 1994 Adam Glass and Charles Hannum. All rights reserved. |
| 3 | * |
| 4 | * Redistribution and use in source and binary forms, with or without |
| 5 | * modification, are permitted provided that the following conditions |
| 6 | * are met: |
| 7 | * 1. Redistributions of source code must retain the above copyright |
| 8 | * notice, this list of conditions and the following disclaimer. |
| 9 | * 2. Redistributions in binary form must reproduce the above copyright |
| 10 | * notice, this list of conditions and the following disclaimer in the |
| 11 | * documentation and/or other materials provided with the distribution. |
| 12 | * 3. All advertising materials mentioning features or use of this software |
| 13 | * must display the following acknowledgement: |
| 14 | * This product includes software developed by Adam Glass and Charles |
| 15 | * Hannum. |
| 16 | * 4. The names of the authors may not be used to endorse or promote products |
| 17 | * derived from this software without specific prior written permission. |
| 18 | * |
| 19 | * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR |
| 20 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 21 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 22 | * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 23 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 24 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 25 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 26 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 27 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 28 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 29 | */ |
| 30 | |
| 31 | #include "opt_compat.h" |
| 32 | #include "opt_sysvipc.h" |
| 33 | |
| 34 | #include <sys/param.h> |
| 35 | #include <sys/systm.h> |
| 36 | #include <sys/sysproto.h> |
| 37 | #include <sys/kernel.h> |
| 38 | #include <sys/sysctl.h> |
| 39 | #include <sys/shm.h> |
| 40 | #include <sys/proc.h> |
| 41 | #include <sys/malloc.h> |
| 42 | #include <sys/mman.h> |
| 43 | #include <sys/stat.h> |
| 44 | #include <sys/sysent.h> |
| 45 | #include <sys/jail.h> |
| 46 | |
| 47 | #include <sys/mplock2.h> |
| 48 | |
| 49 | #include <vm/vm.h> |
| 50 | #include <vm/vm_param.h> |
| 51 | #include <sys/lock.h> |
| 52 | #include <vm/pmap.h> |
| 53 | #include <vm/vm_object.h> |
| 54 | #include <vm/vm_map.h> |
| 55 | #include <vm/vm_page.h> |
| 56 | #include <vm/vm_pager.h> |
| 57 | |
| 58 | static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments"); |
| 59 | |
| 60 | struct oshmctl_args; |
| 61 | static int sys_oshmctl (struct proc *p, struct oshmctl_args *uap); |
| 62 | |
| 63 | static int shmget_allocate_segment (struct proc *p, struct shmget_args *uap, int mode); |
| 64 | static int shmget_existing (struct proc *p, struct shmget_args *uap, int mode, int segnum); |
| 65 | |
| 66 | /* XXX casting to (sy_call_t *) is bogus, as usual. */ |
| 67 | static sy_call_t *shmcalls[] = { |
| 68 | (sy_call_t *)sys_shmat, (sy_call_t *)sys_oshmctl, |
| 69 | (sy_call_t *)sys_shmdt, (sy_call_t *)sys_shmget, |
| 70 | (sy_call_t *)sys_shmctl |
| 71 | }; |
| 72 | |
| 73 | #define SHMSEG_FREE 0x0200 |
| 74 | #define SHMSEG_REMOVED 0x0400 |
| 75 | #define SHMSEG_ALLOCATED 0x0800 |
| 76 | #define SHMSEG_WANTED 0x1000 |
| 77 | |
| 78 | static int shm_last_free, shm_committed, shmalloced; |
| 79 | int shm_nused; |
| 80 | static struct shmid_ds *shmsegs; |
| 81 | |
| 82 | struct shm_handle { |
| 83 | /* vm_offset_t kva; */ |
| 84 | vm_object_t shm_object; |
| 85 | }; |
| 86 | |
| 87 | struct shmmap_state { |
| 88 | vm_offset_t va; |
| 89 | int shmid; |
| 90 | }; |
| 91 | |
| 92 | static void shm_deallocate_segment (struct shmid_ds *); |
| 93 | static int shm_find_segment_by_key (key_t); |
| 94 | static struct shmid_ds *shm_find_segment_by_shmid (int); |
| 95 | static int shm_delete_mapping (struct vmspace *vm, struct shmmap_state *); |
| 96 | static void shmrealloc (void); |
| 97 | static void shminit (void *); |
| 98 | |
| 99 | /* |
| 100 | * Tuneable values |
| 101 | */ |
| 102 | #ifndef SHMMIN |
| 103 | #define SHMMIN 1 |
| 104 | #endif |
| 105 | #ifndef SHMMNI |
| 106 | #define SHMMNI 512 |
| 107 | #endif |
| 108 | #ifndef SHMSEG |
| 109 | #define SHMSEG 1024 |
| 110 | #endif |
| 111 | |
| 112 | struct shminfo shminfo = { |
| 113 | 0, |
| 114 | SHMMIN, |
| 115 | SHMMNI, |
| 116 | SHMSEG, |
| 117 | 0 |
| 118 | }; |
| 119 | |
| 120 | static int shm_use_phys = 1; |
| 121 | |
| 122 | TUNABLE_LONG("kern.ipc.shmmin", &shminfo.shmmin); |
| 123 | TUNABLE_LONG("kern.ipc.shmmni", &shminfo.shmmni); |
| 124 | TUNABLE_LONG("kern.ipc.shmseg", &shminfo.shmseg); |
| 125 | TUNABLE_LONG("kern.ipc.shmmaxpgs", &shminfo.shmall); |
| 126 | TUNABLE_INT("kern.ipc.shm_use_phys", &shm_use_phys); |
| 127 | |
| 128 | SYSCTL_LONG(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0, |
| 129 | "Max shared memory segment size"); |
| 130 | SYSCTL_LONG(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, |
| 131 | "Min shared memory segment size"); |
| 132 | SYSCTL_LONG(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RD, &shminfo.shmmni, 0, |
| 133 | "Max number of shared memory identifiers"); |
| 134 | SYSCTL_LONG(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RW, &shminfo.shmseg, 0, |
| 135 | "Max shared memory segments per process"); |
| 136 | SYSCTL_LONG(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, |
| 137 | "Max pages of shared memory"); |
| 138 | SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, &shm_use_phys, 0, |
| 139 | "Use phys pager allocation instead of swap pager allocation"); |
| 140 | |
| 141 | static int |
| 142 | shm_find_segment_by_key(key_t key) |
| 143 | { |
| 144 | int i; |
| 145 | |
| 146 | for (i = 0; i < shmalloced; i++) { |
| 147 | if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) && |
| 148 | shmsegs[i].shm_perm.key == key) |
| 149 | return i; |
| 150 | } |
| 151 | return -1; |
| 152 | } |
| 153 | |
| 154 | static struct shmid_ds * |
| 155 | shm_find_segment_by_shmid(int shmid) |
| 156 | { |
| 157 | int segnum; |
| 158 | struct shmid_ds *shmseg; |
| 159 | |
| 160 | segnum = IPCID_TO_IX(shmid); |
| 161 | if (segnum < 0 || segnum >= shmalloced) |
| 162 | return NULL; |
| 163 | shmseg = &shmsegs[segnum]; |
| 164 | if ((shmseg->shm_perm.mode & (SHMSEG_ALLOCATED | SHMSEG_REMOVED)) |
| 165 | != SHMSEG_ALLOCATED || |
| 166 | shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid)) { |
| 167 | return NULL; |
| 168 | } |
| 169 | return shmseg; |
| 170 | } |
| 171 | |
| 172 | static void |
| 173 | shm_deallocate_segment(struct shmid_ds *shmseg) |
| 174 | { |
| 175 | struct shm_handle *shm_handle; |
| 176 | size_t size; |
| 177 | |
| 178 | shm_handle = shmseg->shm_internal; |
| 179 | vm_object_deallocate(shm_handle->shm_object); |
| 180 | kfree((caddr_t)shm_handle, M_SHM); |
| 181 | shmseg->shm_internal = NULL; |
| 182 | size = round_page(shmseg->shm_segsz); |
| 183 | shm_committed -= btoc(size); |
| 184 | shm_nused--; |
| 185 | shmseg->shm_perm.mode = SHMSEG_FREE; |
| 186 | } |
| 187 | |
| 188 | static int |
| 189 | shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s) |
| 190 | { |
| 191 | struct shmid_ds *shmseg; |
| 192 | int segnum, result; |
| 193 | size_t size; |
| 194 | |
| 195 | segnum = IPCID_TO_IX(shmmap_s->shmid); |
| 196 | shmseg = &shmsegs[segnum]; |
| 197 | size = round_page(shmseg->shm_segsz); |
| 198 | result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size); |
| 199 | if (result != KERN_SUCCESS) |
| 200 | return EINVAL; |
| 201 | shmmap_s->shmid = -1; |
| 202 | shmseg->shm_dtime = time_second; |
| 203 | if ((--shmseg->shm_nattch <= 0) && |
| 204 | (shmseg->shm_perm.mode & SHMSEG_REMOVED)) { |
| 205 | shm_deallocate_segment(shmseg); |
| 206 | shm_last_free = segnum; |
| 207 | } |
| 208 | return 0; |
| 209 | } |
| 210 | |
| 211 | /* |
| 212 | * MPALMOSTSAFE |
| 213 | */ |
| 214 | int |
| 215 | sys_shmdt(struct shmdt_args *uap) |
| 216 | { |
| 217 | struct thread *td = curthread; |
| 218 | struct proc *p = td->td_proc; |
| 219 | struct shmmap_state *shmmap_s; |
| 220 | long i; |
| 221 | int error; |
| 222 | |
| 223 | if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) |
| 224 | return (ENOSYS); |
| 225 | |
| 226 | get_mplock(); |
| 227 | shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; |
| 228 | if (shmmap_s == NULL) { |
| 229 | error = EINVAL; |
| 230 | goto done; |
| 231 | } |
| 232 | for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) { |
| 233 | if (shmmap_s->shmid != -1 && |
| 234 | shmmap_s->va == (vm_offset_t)uap->shmaddr) |
| 235 | break; |
| 236 | } |
| 237 | if (i == shminfo.shmseg) |
| 238 | error = EINVAL; |
| 239 | else |
| 240 | error = shm_delete_mapping(p->p_vmspace, shmmap_s); |
| 241 | done: |
| 242 | rel_mplock(); |
| 243 | return (error); |
| 244 | } |
| 245 | |
| 246 | /* |
| 247 | * MPALMOSTSAFE |
| 248 | */ |
| 249 | int |
| 250 | sys_shmat(struct shmat_args *uap) |
| 251 | { |
| 252 | struct thread *td = curthread; |
| 253 | struct proc *p = td->td_proc; |
| 254 | int error, flags; |
| 255 | long i; |
| 256 | struct shmid_ds *shmseg; |
| 257 | struct shmmap_state *shmmap_s = NULL; |
| 258 | struct shm_handle *shm_handle; |
| 259 | vm_offset_t attach_va; |
| 260 | vm_prot_t prot; |
| 261 | vm_size_t size; |
| 262 | int rv; |
| 263 | |
| 264 | if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) |
| 265 | return (ENOSYS); |
| 266 | |
| 267 | get_mplock(); |
| 268 | again: |
| 269 | shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; |
| 270 | if (shmmap_s == NULL) { |
| 271 | size = shminfo.shmseg * sizeof(struct shmmap_state); |
| 272 | shmmap_s = kmalloc(size, M_SHM, M_WAITOK); |
| 273 | for (i = 0; i < shminfo.shmseg; i++) |
| 274 | shmmap_s[i].shmid = -1; |
| 275 | if (p->p_vmspace->vm_shm != NULL) { |
| 276 | kfree(shmmap_s, M_SHM); |
| 277 | goto again; |
| 278 | } |
| 279 | p->p_vmspace->vm_shm = (caddr_t)shmmap_s; |
| 280 | } |
| 281 | shmseg = shm_find_segment_by_shmid(uap->shmid); |
| 282 | if (shmseg == NULL) { |
| 283 | error = EINVAL; |
| 284 | goto done; |
| 285 | } |
| 286 | error = ipcperm(p, &shmseg->shm_perm, |
| 287 | (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); |
| 288 | if (error) |
| 289 | goto done; |
| 290 | for (i = 0; i < shminfo.shmseg; i++) { |
| 291 | if (shmmap_s->shmid == -1) |
| 292 | break; |
| 293 | shmmap_s++; |
| 294 | } |
| 295 | if (i >= shminfo.shmseg) { |
| 296 | error = EMFILE; |
| 297 | goto done; |
| 298 | } |
| 299 | size = round_page(shmseg->shm_segsz); |
| 300 | #ifdef VM_PROT_READ_IS_EXEC |
| 301 | prot = VM_PROT_READ | VM_PROT_EXECUTE; |
| 302 | #else |
| 303 | prot = VM_PROT_READ; |
| 304 | #endif |
| 305 | if ((uap->shmflg & SHM_RDONLY) == 0) |
| 306 | prot |= VM_PROT_WRITE; |
| 307 | flags = MAP_ANON | MAP_SHARED; |
| 308 | if (uap->shmaddr) { |
| 309 | flags |= MAP_FIXED; |
| 310 | if (uap->shmflg & SHM_RND) { |
| 311 | attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1); |
| 312 | } else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0) { |
| 313 | attach_va = (vm_offset_t)uap->shmaddr; |
| 314 | } else { |
| 315 | error = EINVAL; |
| 316 | goto done; |
| 317 | } |
| 318 | } else { |
| 319 | /* |
| 320 | * This is just a hint to vm_map_find() about where to put it. |
| 321 | */ |
| 322 | attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr + maxtsiz + maxdsiz); |
| 323 | } |
| 324 | |
| 325 | shm_handle = shmseg->shm_internal; |
| 326 | vm_object_hold(shm_handle->shm_object); |
| 327 | vm_object_chain_wait(shm_handle->shm_object); |
| 328 | vm_object_reference_locked(shm_handle->shm_object); |
| 329 | rv = vm_map_find(&p->p_vmspace->vm_map, |
| 330 | shm_handle->shm_object, 0, |
| 331 | &attach_va, |
| 332 | size, PAGE_SIZE, |
| 333 | ((flags & MAP_FIXED) ? 0 : 1), |
| 334 | VM_MAPTYPE_NORMAL, |
| 335 | prot, prot, |
| 336 | 0); |
| 337 | vm_object_drop(shm_handle->shm_object); |
| 338 | if (rv != KERN_SUCCESS) { |
| 339 | vm_object_deallocate(shm_handle->shm_object); |
| 340 | error = ENOMEM; |
| 341 | goto done; |
| 342 | } |
| 343 | vm_map_inherit(&p->p_vmspace->vm_map, |
| 344 | attach_va, attach_va + size, VM_INHERIT_SHARE); |
| 345 | |
| 346 | KKASSERT(shmmap_s->shmid == -1); |
| 347 | shmmap_s->va = attach_va; |
| 348 | shmmap_s->shmid = uap->shmid; |
| 349 | shmseg->shm_lpid = p->p_pid; |
| 350 | shmseg->shm_atime = time_second; |
| 351 | shmseg->shm_nattch++; |
| 352 | uap->sysmsg_resultp = (void *)attach_va; |
| 353 | error = 0; |
| 354 | done: |
| 355 | rel_mplock(); |
| 356 | return error; |
| 357 | } |
| 358 | |
| 359 | struct oshmid_ds { |
| 360 | struct ipc_perm shm_perm; /* operation perms */ |
| 361 | int shm_segsz; /* size of segment (bytes) */ |
| 362 | ushort shm_cpid; /* pid, creator */ |
| 363 | ushort shm_lpid; /* pid, last operation */ |
| 364 | short shm_nattch; /* no. of current attaches */ |
| 365 | time_t shm_atime; /* last attach time */ |
| 366 | time_t shm_dtime; /* last detach time */ |
| 367 | time_t shm_ctime; /* last change time */ |
| 368 | void *shm_handle; /* internal handle for shm segment */ |
| 369 | }; |
| 370 | |
| 371 | struct oshmctl_args { |
| 372 | struct sysmsg sysmsg; |
| 373 | int shmid; |
| 374 | int cmd; |
| 375 | struct oshmid_ds *ubuf; |
| 376 | }; |
| 377 | |
| 378 | /* |
| 379 | * MPALMOSTSAFE |
| 380 | */ |
| 381 | static int |
| 382 | sys_oshmctl(struct proc *p, struct oshmctl_args *uap) |
| 383 | { |
| 384 | #ifdef COMPAT_43 |
| 385 | struct thread *td = curthread; |
| 386 | struct shmid_ds *shmseg; |
| 387 | struct oshmid_ds outbuf; |
| 388 | int error; |
| 389 | |
| 390 | if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) |
| 391 | return (ENOSYS); |
| 392 | |
| 393 | get_mplock(); |
| 394 | shmseg = shm_find_segment_by_shmid(uap->shmid); |
| 395 | if (shmseg == NULL) { |
| 396 | error = EINVAL; |
| 397 | goto done; |
| 398 | } |
| 399 | |
| 400 | switch (uap->cmd) { |
| 401 | case IPC_STAT: |
| 402 | error = ipcperm(p, &shmseg->shm_perm, IPC_R); |
| 403 | if (error) |
| 404 | break; |
| 405 | outbuf.shm_perm = shmseg->shm_perm; |
| 406 | outbuf.shm_segsz = shmseg->shm_segsz; |
| 407 | outbuf.shm_cpid = shmseg->shm_cpid; |
| 408 | outbuf.shm_lpid = shmseg->shm_lpid; |
| 409 | outbuf.shm_nattch = shmseg->shm_nattch; |
| 410 | outbuf.shm_atime = shmseg->shm_atime; |
| 411 | outbuf.shm_dtime = shmseg->shm_dtime; |
| 412 | outbuf.shm_ctime = shmseg->shm_ctime; |
| 413 | outbuf.shm_handle = shmseg->shm_internal; |
| 414 | error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf)); |
| 415 | break; |
| 416 | default: |
| 417 | /* XXX casting to (sy_call_t *) is bogus, as usual. */ |
| 418 | error = sys_shmctl((struct shmctl_args *)uap); |
| 419 | } |
| 420 | done: |
| 421 | rel_mplock(); |
| 422 | return error; |
| 423 | #else |
| 424 | return EINVAL; |
| 425 | #endif |
| 426 | } |
| 427 | |
| 428 | /* |
| 429 | * MPALMOSTSAFE |
| 430 | */ |
| 431 | int |
| 432 | sys_shmctl(struct shmctl_args *uap) |
| 433 | { |
| 434 | struct thread *td = curthread; |
| 435 | struct proc *p = td->td_proc; |
| 436 | int error; |
| 437 | struct shmid_ds inbuf; |
| 438 | struct shmid_ds *shmseg; |
| 439 | |
| 440 | if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) |
| 441 | return (ENOSYS); |
| 442 | |
| 443 | get_mplock(); |
| 444 | shmseg = shm_find_segment_by_shmid(uap->shmid); |
| 445 | if (shmseg == NULL) { |
| 446 | error = EINVAL; |
| 447 | goto done; |
| 448 | } |
| 449 | |
| 450 | switch (uap->cmd) { |
| 451 | case IPC_STAT: |
| 452 | error = ipcperm(p, &shmseg->shm_perm, IPC_R); |
| 453 | if (error == 0) |
| 454 | error = copyout(shmseg, uap->buf, sizeof(inbuf)); |
| 455 | break; |
| 456 | case IPC_SET: |
| 457 | error = ipcperm(p, &shmseg->shm_perm, IPC_M); |
| 458 | if (error == 0) |
| 459 | error = copyin(uap->buf, &inbuf, sizeof(inbuf)); |
| 460 | if (error == 0) { |
| 461 | shmseg->shm_perm.uid = inbuf.shm_perm.uid; |
| 462 | shmseg->shm_perm.gid = inbuf.shm_perm.gid; |
| 463 | shmseg->shm_perm.mode = |
| 464 | (shmseg->shm_perm.mode & ~ACCESSPERMS) | |
| 465 | (inbuf.shm_perm.mode & ACCESSPERMS); |
| 466 | shmseg->shm_ctime = time_second; |
| 467 | } |
| 468 | break; |
| 469 | case IPC_RMID: |
| 470 | error = ipcperm(p, &shmseg->shm_perm, IPC_M); |
| 471 | if (error == 0) { |
| 472 | shmseg->shm_perm.key = IPC_PRIVATE; |
| 473 | shmseg->shm_perm.mode |= SHMSEG_REMOVED; |
| 474 | if (shmseg->shm_nattch <= 0) { |
| 475 | shm_deallocate_segment(shmseg); |
| 476 | shm_last_free = IPCID_TO_IX(uap->shmid); |
| 477 | } |
| 478 | } |
| 479 | break; |
| 480 | #if 0 |
| 481 | case SHM_LOCK: |
| 482 | case SHM_UNLOCK: |
| 483 | #endif |
| 484 | default: |
| 485 | error = EINVAL; |
| 486 | break; |
| 487 | } |
| 488 | done: |
| 489 | rel_mplock(); |
| 490 | return error; |
| 491 | } |
| 492 | |
| 493 | static int |
| 494 | shmget_existing(struct proc *p, struct shmget_args *uap, int mode, int segnum) |
| 495 | { |
| 496 | struct shmid_ds *shmseg; |
| 497 | int error; |
| 498 | |
| 499 | shmseg = &shmsegs[segnum]; |
| 500 | if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { |
| 501 | /* |
| 502 | * This segment is in the process of being allocated. Wait |
| 503 | * until it's done, and look the key up again (in case the |
| 504 | * allocation failed or it was freed). |
| 505 | */ |
| 506 | shmseg->shm_perm.mode |= SHMSEG_WANTED; |
| 507 | error = tsleep((caddr_t)shmseg, PCATCH, "shmget", 0); |
| 508 | if (error) |
| 509 | return error; |
| 510 | return EAGAIN; |
| 511 | } |
| 512 | if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL)) |
| 513 | return EEXIST; |
| 514 | error = ipcperm(p, &shmseg->shm_perm, mode); |
| 515 | if (error) |
| 516 | return error; |
| 517 | if (uap->size && uap->size > shmseg->shm_segsz) |
| 518 | return EINVAL; |
| 519 | uap->sysmsg_result = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); |
| 520 | return 0; |
| 521 | } |
| 522 | |
| 523 | static int |
| 524 | shmget_allocate_segment(struct proc *p, struct shmget_args *uap, int mode) |
| 525 | { |
| 526 | int i, segnum, shmid; |
| 527 | size_t size; |
| 528 | struct ucred *cred = p->p_ucred; |
| 529 | struct shmid_ds *shmseg; |
| 530 | struct shm_handle *shm_handle; |
| 531 | |
| 532 | if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax) |
| 533 | return EINVAL; |
| 534 | if (shm_nused >= shminfo.shmmni) /* any shmids left? */ |
| 535 | return ENOSPC; |
| 536 | size = round_page(uap->size); |
| 537 | if (shm_committed + btoc(size) > shminfo.shmall) |
| 538 | return ENOMEM; |
| 539 | if (shm_last_free < 0) { |
| 540 | shmrealloc(); /* maybe expand the shmsegs[] array */ |
| 541 | for (i = 0; i < shmalloced; i++) { |
| 542 | if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) |
| 543 | break; |
| 544 | } |
| 545 | if (i == shmalloced) |
| 546 | return ENOSPC; |
| 547 | segnum = i; |
| 548 | } else { |
| 549 | segnum = shm_last_free; |
| 550 | shm_last_free = -1; |
| 551 | } |
| 552 | shmseg = &shmsegs[segnum]; |
| 553 | /* |
| 554 | * In case we sleep in malloc(), mark the segment present but deleted |
| 555 | * so that noone else tries to create the same key. |
| 556 | */ |
| 557 | shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; |
| 558 | shmseg->shm_perm.key = uap->key; |
| 559 | shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff; |
| 560 | shm_handle = kmalloc(sizeof(struct shm_handle), M_SHM, M_WAITOK); |
| 561 | shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); |
| 562 | |
| 563 | /* |
| 564 | * We make sure that we have allocated a pager before we need |
| 565 | * to. |
| 566 | */ |
| 567 | if (shm_use_phys) { |
| 568 | shm_handle->shm_object = |
| 569 | phys_pager_alloc(NULL, size, VM_PROT_DEFAULT, 0); |
| 570 | } else { |
| 571 | shm_handle->shm_object = |
| 572 | swap_pager_alloc(NULL, size, VM_PROT_DEFAULT, 0); |
| 573 | } |
| 574 | vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING); |
| 575 | vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT); |
| 576 | |
| 577 | shmseg->shm_internal = shm_handle; |
| 578 | shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; |
| 579 | shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; |
| 580 | shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | |
| 581 | (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; |
| 582 | shmseg->shm_segsz = uap->size; |
| 583 | shmseg->shm_cpid = p->p_pid; |
| 584 | shmseg->shm_lpid = shmseg->shm_nattch = 0; |
| 585 | shmseg->shm_atime = shmseg->shm_dtime = 0; |
| 586 | shmseg->shm_ctime = time_second; |
| 587 | shm_committed += btoc(size); |
| 588 | shm_nused++; |
| 589 | |
| 590 | /* |
| 591 | * If a physical mapping is desired and we have a ton of free pages |
| 592 | * we pre-allocate the pages here in order to avoid on-the-fly |
| 593 | * allocation later. This has a big effect on database warm-up |
| 594 | * times since DFly supports concurrent page faults coming from the |
| 595 | * same VM object for pages which already exist. |
| 596 | * |
| 597 | * This can hang the kernel for a while so only do it if shm_use_phys |
| 598 | * is set to 2 or higher. |
| 599 | */ |
| 600 | if (shm_use_phys > 1) { |
| 601 | vm_pindex_t pi, pmax; |
| 602 | vm_page_t m; |
| 603 | |
| 604 | pmax = round_page(shmseg->shm_segsz) >> PAGE_SHIFT; |
| 605 | vm_object_hold(shm_handle->shm_object); |
| 606 | if (pmax > vmstats.v_free_count) |
| 607 | pmax = vmstats.v_free_count; |
| 608 | for (pi = 0; pi < pmax; ++pi) { |
| 609 | m = vm_page_grab(shm_handle->shm_object, pi, |
| 610 | VM_ALLOC_SYSTEM | VM_ALLOC_NULL_OK | |
| 611 | VM_ALLOC_ZERO); |
| 612 | if (m == NULL) |
| 613 | break; |
| 614 | vm_pager_get_page(shm_handle->shm_object, &m, 1); |
| 615 | vm_page_activate(m); |
| 616 | vm_page_wakeup(m); |
| 617 | lwkt_yield(); |
| 618 | } |
| 619 | vm_object_drop(shm_handle->shm_object); |
| 620 | } |
| 621 | |
| 622 | if (shmseg->shm_perm.mode & SHMSEG_WANTED) { |
| 623 | /* |
| 624 | * Somebody else wanted this key while we were asleep. Wake |
| 625 | * them up now. |
| 626 | */ |
| 627 | shmseg->shm_perm.mode &= ~SHMSEG_WANTED; |
| 628 | wakeup((caddr_t)shmseg); |
| 629 | } |
| 630 | uap->sysmsg_result = shmid; |
| 631 | return 0; |
| 632 | } |
| 633 | |
| 634 | /* |
| 635 | * MPALMOSTSAFE |
| 636 | */ |
| 637 | int |
| 638 | sys_shmget(struct shmget_args *uap) |
| 639 | { |
| 640 | struct thread *td = curthread; |
| 641 | struct proc *p = td->td_proc; |
| 642 | int segnum, mode, error; |
| 643 | |
| 644 | if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) |
| 645 | return (ENOSYS); |
| 646 | |
| 647 | mode = uap->shmflg & ACCESSPERMS; |
| 648 | get_mplock(); |
| 649 | |
| 650 | if (uap->key != IPC_PRIVATE) { |
| 651 | again: |
| 652 | segnum = shm_find_segment_by_key(uap->key); |
| 653 | if (segnum >= 0) { |
| 654 | error = shmget_existing(p, uap, mode, segnum); |
| 655 | if (error == EAGAIN) |
| 656 | goto again; |
| 657 | goto done; |
| 658 | } |
| 659 | if ((uap->shmflg & IPC_CREAT) == 0) { |
| 660 | error = ENOENT; |
| 661 | goto done; |
| 662 | } |
| 663 | } |
| 664 | error = shmget_allocate_segment(p, uap, mode); |
| 665 | done: |
| 666 | rel_mplock(); |
| 667 | return (error); |
| 668 | } |
| 669 | |
| 670 | /* |
| 671 | * shmsys_args(int which, int a2, ...) (VARARGS) |
| 672 | * |
| 673 | * MPALMOSTSAFE |
| 674 | */ |
| 675 | int |
| 676 | sys_shmsys(struct shmsys_args *uap) |
| 677 | { |
| 678 | struct thread *td = curthread; |
| 679 | unsigned int which = (unsigned int)uap->which; |
| 680 | int error; |
| 681 | |
| 682 | if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) |
| 683 | return (ENOSYS); |
| 684 | |
| 685 | if (which >= NELEM(shmcalls)) |
| 686 | return EINVAL; |
| 687 | get_mplock(); |
| 688 | bcopy(&uap->a2, &uap->which, |
| 689 | sizeof(struct shmsys_args) - offsetof(struct shmsys_args, a2)); |
| 690 | error = ((*shmcalls[which])(uap)); |
| 691 | rel_mplock(); |
| 692 | |
| 693 | return(error); |
| 694 | } |
| 695 | |
| 696 | void |
| 697 | shmfork(struct proc *p1, struct proc *p2) |
| 698 | { |
| 699 | struct shmmap_state *shmmap_s; |
| 700 | size_t size; |
| 701 | int i; |
| 702 | |
| 703 | get_mplock(); |
| 704 | size = shminfo.shmseg * sizeof(struct shmmap_state); |
| 705 | shmmap_s = kmalloc(size, M_SHM, M_WAITOK); |
| 706 | bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size); |
| 707 | p2->p_vmspace->vm_shm = (caddr_t)shmmap_s; |
| 708 | for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) { |
| 709 | if (shmmap_s->shmid != -1) |
| 710 | shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++; |
| 711 | } |
| 712 | rel_mplock(); |
| 713 | } |
| 714 | |
| 715 | void |
| 716 | shmexit(struct vmspace *vm) |
| 717 | { |
| 718 | struct shmmap_state *base, *shm; |
| 719 | int i; |
| 720 | |
| 721 | if ((base = (struct shmmap_state *)vm->vm_shm) != NULL) { |
| 722 | vm->vm_shm = NULL; |
| 723 | get_mplock(); |
| 724 | for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) { |
| 725 | if (shm->shmid != -1) |
| 726 | shm_delete_mapping(vm, shm); |
| 727 | } |
| 728 | kfree(base, M_SHM); |
| 729 | rel_mplock(); |
| 730 | } |
| 731 | } |
| 732 | |
| 733 | static void |
| 734 | shmrealloc(void) |
| 735 | { |
| 736 | int i; |
| 737 | struct shmid_ds *newsegs; |
| 738 | |
| 739 | if (shmalloced >= shminfo.shmmni) |
| 740 | return; |
| 741 | |
| 742 | newsegs = kmalloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK); |
| 743 | for (i = 0; i < shmalloced; i++) |
| 744 | bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0])); |
| 745 | for (; i < shminfo.shmmni; i++) { |
| 746 | shmsegs[i].shm_perm.mode = SHMSEG_FREE; |
| 747 | shmsegs[i].shm_perm.seq = 0; |
| 748 | } |
| 749 | kfree(shmsegs, M_SHM); |
| 750 | shmsegs = newsegs; |
| 751 | shmalloced = shminfo.shmmni; |
| 752 | } |
| 753 | |
| 754 | static void |
| 755 | shminit(void *dummy) |
| 756 | { |
| 757 | int i; |
| 758 | |
| 759 | /* |
| 760 | * If not overridden by a tunable set the maximum shm to |
| 761 | * 2/3 of main memory. |
| 762 | */ |
| 763 | if (shminfo.shmall == 0) |
| 764 | shminfo.shmall = (size_t)vmstats.v_page_count * 2 / 3; |
| 765 | |
| 766 | shminfo.shmmax = shminfo.shmall * PAGE_SIZE; |
| 767 | shmalloced = shminfo.shmmni; |
| 768 | shmsegs = kmalloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK); |
| 769 | for (i = 0; i < shmalloced; i++) { |
| 770 | shmsegs[i].shm_perm.mode = SHMSEG_FREE; |
| 771 | shmsegs[i].shm_perm.seq = 0; |
| 772 | } |
| 773 | shm_last_free = 0; |
| 774 | shm_nused = 0; |
| 775 | shm_committed = 0; |
| 776 | } |
| 777 | SYSINIT(sysv_shm, SI_SUB_SYSV_SHM, SI_ORDER_FIRST, shminit, NULL); |