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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 | /* * linux/ipc/msg.c * Copyright (C) 1992 Krishna Balasubramanian */ #include <linux/errno.h> #include <linux/sched.h> #include <linux/msg.h> #include <linux/stat.h> #include <linux/malloc.h> #include <asm/segment.h> extern int ipcperms (struct ipc_perm *ipcp, short msgflg); static void freeque (int id); static int newque (key_t key, int msgflg); static int findkey (key_t key); static struct msqid_ds *msgque[MSGMNI]; static int msgbytes = 0; static int msghdrs = 0; static unsigned short msg_seq = 0; static int used_queues = 0; static int max_msqid = 0; static struct wait_queue *msg_lock = NULL; void msg_init (void) { int id; for (id=0; id < MSGMNI; id++) msgque[id] = (struct msqid_ds *) IPC_UNUSED; msgbytes = msghdrs = msg_seq = max_msqid = used_queues = 0; msg_lock = NULL; return; } int sys_msgsnd (int msqid, struct msgbuf *msgp, int msgsz, int msgflg) { int id, err; struct msqid_ds *msq; struct ipc_perm *ipcp; struct msg *msgh; long mtype; if (msgsz > MSGMAX || msgsz < 0 || msqid < 0) return -EINVAL; if (!msgp) return -EFAULT; err = verify_area (VERIFY_READ, msgp->mtext, msgsz); if (err) return err; if ((mtype = get_fs_long (&msgp->mtype)) < 1) return -EINVAL; id = msqid % MSGMNI; msq = msgque [id]; if (msq == IPC_UNUSED || msq == IPC_NOID) return -EINVAL; ipcp = &msq->msg_perm; slept: if (ipcp->seq != (msqid / MSGMNI)) return -EIDRM; if (ipcperms(ipcp, S_IWUGO)) return -EACCES; if (msgsz + msq->msg_cbytes > msq->msg_qbytes) { /* no space in queue */ if (msgflg & IPC_NOWAIT) return -EAGAIN; if (current->signal & ~current->blocked) return -EINTR; interruptible_sleep_on (&msq->wwait); goto slept; } /* allocate message header and text space*/ msgh = (struct msg *) kmalloc (sizeof(*msgh) + msgsz, GFP_USER); if (!msgh) return -ENOMEM; msgh->msg_spot = (char *) (msgh + 1); memcpy_fromfs (msgh->msg_spot, msgp->mtext, msgsz); if (msgque[id] == IPC_UNUSED || msgque[id] == IPC_NOID || ipcp->seq != msqid / MSGMNI) { kfree(msgh); return -EIDRM; } msgh->msg_next = NULL; if (!msq->msg_first) msq->msg_first = msq->msg_last = msgh; else { msq->msg_last->msg_next = msgh; msq->msg_last = msgh; } msgh->msg_ts = msgsz; msgh->msg_type = mtype; msq->msg_cbytes += msgsz; msgbytes += msgsz; msghdrs++; msq->msg_qnum++; msq->msg_lspid = current->pid; msq->msg_stime = CURRENT_TIME; if (msq->rwait) wake_up (&msq->rwait); return msgsz; } int sys_msgrcv (int msqid, struct msgbuf *msgp, int msgsz, long msgtyp, int msgflg) { struct msqid_ds *msq; struct ipc_perm *ipcp; struct msg *tmsg, *leastp = NULL; struct msg *nmsg = NULL; int id, err; if (msqid < 0 || msgsz < 0) return -EINVAL; if (!msgp || !msgp->mtext) return -EFAULT; err = verify_area (VERIFY_WRITE, msgp->mtext, msgsz); if (err) return err; id = msqid % MSGMNI; msq = msgque [id]; if (msq == IPC_NOID || msq == IPC_UNUSED) return -EINVAL; ipcp = &msq->msg_perm; /* * find message of correct type. * msgtyp = 0 => get first. * msgtyp > 0 => get first message of matching type. * msgtyp < 0 => get message with least type must be < abs(msgtype). */ while (!nmsg) { if(ipcp->seq != msqid / MSGMNI) return -EIDRM; if (ipcperms (ipcp, S_IRUGO)) return -EACCES; if (msgtyp == 0) nmsg = msq->msg_first; else if (msgtyp > 0) { if (msgflg & MSG_EXCEPT) { for (tmsg = msq->msg_first; tmsg; tmsg = tmsg->msg_next) if (tmsg->msg_type != msgtyp) break; nmsg = tmsg; } else { for (tmsg = msq->msg_first; tmsg; tmsg = tmsg->msg_next) if (tmsg->msg_type == msgtyp) break; nmsg = tmsg; } } else { for (leastp = tmsg = msq->msg_first; tmsg; tmsg = tmsg->msg_next) if (tmsg->msg_type < leastp->msg_type) leastp = tmsg; if (leastp && leastp->msg_type <= - msgtyp) nmsg = leastp; } if (nmsg) { /* done finding a message */ if ((msgsz < nmsg->msg_ts) && !(msgflg & MSG_NOERROR)) return -E2BIG; msgsz = (msgsz > nmsg->msg_ts)? nmsg->msg_ts : msgsz; if (nmsg == msq->msg_first) msq->msg_first = nmsg->msg_next; else { for (tmsg= msq->msg_first; tmsg; tmsg = tmsg->msg_next) if (tmsg->msg_next == nmsg) break; tmsg->msg_next = nmsg->msg_next; if (nmsg == msq->msg_last) msq->msg_last = tmsg; } if (!(--msq->msg_qnum)) msq->msg_last = msq->msg_first = NULL; msq->msg_rtime = CURRENT_TIME; msq->msg_lrpid = current->pid; msgbytes -= nmsg->msg_ts; msghdrs--; msq->msg_cbytes -= nmsg->msg_ts; if (msq->wwait) wake_up (&msq->wwait); put_fs_long (nmsg->msg_type, &msgp->mtype); memcpy_tofs (msgp->mtext, nmsg->msg_spot, msgsz); kfree(nmsg); return msgsz; } else { /* did not find a message */ if (msgflg & IPC_NOWAIT) return -ENOMSG; if (current->signal & ~current->blocked) return -EINTR; interruptible_sleep_on (&msq->rwait); } } /* end while */ return -1; } static int findkey (key_t key) { int id; struct msqid_ds *msq; for (id=0; id <= max_msqid; id++) { while ((msq = msgque[id]) == IPC_NOID) interruptible_sleep_on (&msg_lock); if (msq == IPC_UNUSED) continue; if (key == msq->msg_perm.key) return id; } return -1; } static int newque (key_t key, int msgflg) { int id; struct msqid_ds *msq; struct ipc_perm *ipcp; for (id=0; id < MSGMNI; id++) if (msgque[id] == IPC_UNUSED) { msgque[id] = (struct msqid_ds *) IPC_NOID; goto found; } return -ENOSPC; found: msq = (struct msqid_ds *) kmalloc (sizeof (*msq), GFP_KERNEL); if (!msq) { msgque[id] = (struct msqid_ds *) IPC_UNUSED; if (msg_lock) wake_up (&msg_lock); return -ENOMEM; } ipcp = &msq->msg_perm; ipcp->mode = (msgflg & S_IRWXUGO); ipcp->key = key; ipcp->cuid = ipcp->uid = current->euid; ipcp->gid = ipcp->cgid = current->egid; ipcp->seq = msg_seq; msq->msg_first = msq->msg_last = NULL; msq->rwait = msq->wwait = NULL; msq->msg_cbytes = msq->msg_qnum = 0; msq->msg_lspid = msq->msg_lrpid = 0; msq->msg_stime = msq->msg_rtime = 0; msq->msg_qbytes = MSGMNB; msq->msg_ctime = CURRENT_TIME; if (id > max_msqid) max_msqid = id; msgque[id] = msq; used_queues++; if (msg_lock) wake_up (&msg_lock); return (int) msg_seq * MSGMNI + id; } int sys_msgget (key_t key, int msgflg) { int id; struct msqid_ds *msq; if (key == IPC_PRIVATE) return newque(key, msgflg); if ((id = findkey (key)) == -1) { /* key not used */ if (!(msgflg & IPC_CREAT)) return -ENOENT; return newque(key, msgflg); } if (msgflg & IPC_CREAT && msgflg & IPC_EXCL) return -EEXIST; msq = msgque[id]; if (msq == IPC_UNUSED || msq == IPC_NOID) return -EIDRM; if (ipcperms(&msq->msg_perm, msgflg)) return -EACCES; return msq->msg_perm.seq * MSGMNI +id; } static void freeque (int id) { struct msqid_ds *msq = msgque[id]; struct msg *msgp, *msgh; msq->msg_perm.seq++; msg_seq++; msgbytes -= msq->msg_cbytes; if (id == max_msqid) while (max_msqid && (msgque[--max_msqid] == IPC_UNUSED)); msgque[id] = (struct msqid_ds *) IPC_UNUSED; used_queues--; while (msq->rwait || msq->wwait) { if (msq->rwait) wake_up (&msq->rwait); if (msq->wwait) wake_up (&msq->wwait); schedule(); } for (msgp = msq->msg_first; msgp; msgp = msgh ) { msgh = msgp->msg_next; msghdrs--; kfree(msgp); } kfree(msq); } int sys_msgctl (int msqid, int cmd, struct msqid_ds *buf) { int id, err; struct msqid_ds *msq, tbuf; struct ipc_perm *ipcp; if (msqid < 0 || cmd < 0) return -EINVAL; switch (cmd) { case IPC_INFO: case MSG_INFO: if (!buf) return -EFAULT; { struct msginfo msginfo; msginfo.msgmni = MSGMNI; msginfo.msgmax = MSGMAX; msginfo.msgmnb = MSGMNB; msginfo.msgmap = MSGMAP; msginfo.msgpool = MSGPOOL; msginfo.msgtql = MSGTQL; msginfo.msgssz = MSGSSZ; msginfo.msgseg = MSGSEG; if (cmd == MSG_INFO) { msginfo.msgpool = used_queues; msginfo.msgmap = msghdrs; msginfo.msgtql = msgbytes; } err = verify_area (VERIFY_WRITE, buf, sizeof (struct msginfo)); if (err) return err; memcpy_tofs (buf, &msginfo, sizeof(struct msginfo)); return max_msqid; } case MSG_STAT: if (!buf) return -EFAULT; err = verify_area (VERIFY_WRITE, buf, sizeof (*msq)); if (err) return err; if (msqid > max_msqid) return -EINVAL; msq = msgque[msqid]; if (msq == IPC_UNUSED || msq == IPC_NOID) return -EINVAL; if (ipcperms (&msq->msg_perm, S_IRUGO)) return -EACCES; id = msqid + msq->msg_perm.seq * MSGMNI; memcpy_tofs (buf, msq, sizeof(*msq)); return id; case IPC_SET: if (!buf) return -EFAULT; memcpy_fromfs (&tbuf, buf, sizeof (*buf)); break; case IPC_STAT: if (!buf) return -EFAULT; err = verify_area (VERIFY_WRITE, buf, sizeof(*msq)); if (err) return err; break; } id = msqid % MSGMNI; msq = msgque [id]; if (msq == IPC_UNUSED || msq == IPC_NOID) return -EINVAL; ipcp = &msq->msg_perm; if (ipcp->seq != msqid / MSGMNI) return -EIDRM; switch (cmd) { case IPC_STAT: if (ipcperms (ipcp, S_IRUGO)) return -EACCES; memcpy_tofs (buf, msq, sizeof (*msq)); return 0; break; case IPC_RMID: case IPC_SET: if (!suser() && current->euid != ipcp->cuid && current->euid != ipcp->uid) return -EPERM; if (cmd == IPC_RMID) { freeque (id); return 0; } if (tbuf.msg_qbytes > MSGMNB && !suser()) return -EPERM; msq->msg_qbytes = tbuf.msg_qbytes; ipcp->uid = tbuf.msg_perm.uid; ipcp->gid = tbuf.msg_perm.gid; ipcp->mode = (ipcp->mode & ~S_IRWXUGO) | (S_IRWXUGO & tbuf.msg_perm.mode); msq->msg_ctime = CURRENT_TIME; break; default: return -EINVAL; break; } return 0; } |