3 * Copyright (C) 1992 Krishna Balasubramanian
5 * Removed all the remaining kerneld mess
6 * Catch the -EFAULT stuff properly
7 * Use GFP_KERNEL for messages as in 1.2
8 * Fixed up the unchecked user space derefs
9 * Copyright (C) 1998 Alan Cox & Andi Kleen
11 * /proc/sysvipc/msg support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
13 * mostly rewritten, threaded and wake-one semantics added
14 * MSGMAX limit removed, sysctl's added
15 * (c) 1999 Manfred Spraul <manfreds@colorfullife.com>
18 #include <linux/config.h>
19 #include <linux/slab.h>
20 #include <linux/msg.h>
21 #include <linux/spinlock.h>
22 #include <linux/init.h>
23 #include <linux/proc_fs.h>
24 #include <linux/list.h>
25 #include <linux/security.h>
26 #include <linux/sched.h>
27 #include <linux/syscalls.h>
28 #include <linux/audit.h>
29 #include <asm/current.h>
30 #include <asm/uaccess.h>
34 int msg_ctlmax = MSGMAX;
35 int msg_ctlmnb = MSGMNB;
36 int msg_ctlmni = MSGMNI;
38 /* one msg_receiver structure for each sleeping receiver */
40 struct list_head r_list;
41 struct task_struct* r_tsk;
47 struct msg_msg* volatile r_msg;
50 /* one msg_sender for each sleeping sender */
52 struct list_head list;
53 struct task_struct* tsk;
57 #define SEARCH_EQUAL 2
58 #define SEARCH_NOTEQUAL 3
59 #define SEARCH_LESSEQUAL 4
61 static atomic_t msg_bytes = ATOMIC_INIT(0);
62 static atomic_t msg_hdrs = ATOMIC_INIT(0);
64 static struct ipc_ids msg_ids;
66 #define msg_lock(id) ((struct msg_queue*)ipc_lock(&msg_ids,id))
67 #define msg_unlock(msq) ipc_unlock(&(msq)->q_perm)
68 #define msg_rmid(id) ((struct msg_queue*)ipc_rmid(&msg_ids,id))
69 #define msg_checkid(msq, msgid) \
70 ipc_checkid(&msg_ids,&msq->q_perm,msgid)
71 #define msg_buildid(id, seq) \
72 ipc_buildid(&msg_ids, id, seq)
74 static void freeque (struct msg_queue *msq, int id);
75 static int newque (key_t key, int msgflg);
77 static int sysvipc_msg_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data);
80 void __init msg_init (void)
82 ipc_init_ids(&msg_ids,msg_ctlmni);
85 create_proc_read_entry("sysvipc/msg", 0, NULL, sysvipc_msg_read_proc, NULL);
89 static int newque (key_t key, int msgflg)
93 struct msg_queue *msq;
95 msq = ipc_rcu_alloc(sizeof(*msq));
99 msq->q_perm.mode = (msgflg & S_IRWXUGO);
100 msq->q_perm.key = key;
101 msq->q_perm.xid = vx_current_xid();
103 msq->q_perm.security = NULL;
104 retval = security_msg_queue_alloc(msq);
110 id = ipc_addid(&msg_ids, &msq->q_perm, msg_ctlmni);
112 security_msg_queue_free(msq);
117 msq->q_stime = msq->q_rtime = 0;
118 msq->q_ctime = get_seconds();
119 msq->q_cbytes = msq->q_qnum = 0;
120 msq->q_qbytes = msg_ctlmnb;
121 msq->q_lspid = msq->q_lrpid = 0;
122 INIT_LIST_HEAD(&msq->q_messages);
123 INIT_LIST_HEAD(&msq->q_receivers);
124 INIT_LIST_HEAD(&msq->q_senders);
127 return msg_buildid(id,msq->q_perm.seq);
130 static inline void ss_add(struct msg_queue* msq, struct msg_sender* mss)
133 current->state=TASK_INTERRUPTIBLE;
134 list_add_tail(&mss->list,&msq->q_senders);
137 static inline void ss_del(struct msg_sender* mss)
139 if(mss->list.next != NULL)
140 list_del(&mss->list);
143 static void ss_wakeup(struct list_head* h, int kill)
145 struct list_head *tmp;
149 struct msg_sender* mss;
151 mss = list_entry(tmp,struct msg_sender,list);
155 wake_up_process(mss->tsk);
159 static void expunge_all(struct msg_queue* msq, int res)
161 struct list_head *tmp;
163 tmp = msq->q_receivers.next;
164 while (tmp != &msq->q_receivers) {
165 struct msg_receiver* msr;
167 msr = list_entry(tmp,struct msg_receiver,r_list);
170 wake_up_process(msr->r_tsk);
172 msr->r_msg = ERR_PTR(res);
176 * freeque() wakes up waiters on the sender and receiver waiting queue,
177 * removes the message queue from message queue ID
178 * array, and cleans up all the messages associated with this queue.
180 * msg_ids.sem and the spinlock for this message queue is hold
181 * before freeque() is called. msg_ids.sem remains locked on exit.
183 static void freeque (struct msg_queue *msq, int id)
185 struct list_head *tmp;
187 expunge_all(msq,-EIDRM);
188 ss_wakeup(&msq->q_senders,1);
192 tmp = msq->q_messages.next;
193 while(tmp != &msq->q_messages) {
194 struct msg_msg* msg = list_entry(tmp,struct msg_msg,m_list);
196 atomic_dec(&msg_hdrs);
199 atomic_sub(msq->q_cbytes, &msg_bytes);
200 security_msg_queue_free(msq);
204 asmlinkage long sys_msgget (key_t key, int msgflg)
206 int id, ret = -EPERM;
207 struct msg_queue *msq;
210 if (key == IPC_PRIVATE)
211 ret = newque(key, msgflg);
212 else if ((id = ipc_findkey(&msg_ids, key)) == -1) { /* key not used */
213 if (!(msgflg & IPC_CREAT))
216 ret = newque(key, msgflg);
217 } else if (msgflg & IPC_CREAT && msgflg & IPC_EXCL) {
223 if (ipcperms(&msq->q_perm, msgflg))
226 int qid = msg_buildid(id, msq->q_perm.seq);
227 ret = security_msg_queue_associate(msq, msgflg);
237 static inline unsigned long copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version)
241 return copy_to_user (buf, in, sizeof(*in));
246 memset(&out,0,sizeof(out));
248 ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm);
250 out.msg_stime = in->msg_stime;
251 out.msg_rtime = in->msg_rtime;
252 out.msg_ctime = in->msg_ctime;
254 if(in->msg_cbytes > USHRT_MAX)
255 out.msg_cbytes = USHRT_MAX;
257 out.msg_cbytes = in->msg_cbytes;
258 out.msg_lcbytes = in->msg_cbytes;
260 if(in->msg_qnum > USHRT_MAX)
261 out.msg_qnum = USHRT_MAX;
263 out.msg_qnum = in->msg_qnum;
265 if(in->msg_qbytes > USHRT_MAX)
266 out.msg_qbytes = USHRT_MAX;
268 out.msg_qbytes = in->msg_qbytes;
269 out.msg_lqbytes = in->msg_qbytes;
271 out.msg_lspid = in->msg_lspid;
272 out.msg_lrpid = in->msg_lrpid;
274 return copy_to_user (buf, &out, sizeof(out));
282 unsigned long qbytes;
288 static inline unsigned long copy_msqid_from_user(struct msq_setbuf *out, void __user *buf, int version)
293 struct msqid64_ds tbuf;
295 if (copy_from_user (&tbuf, buf, sizeof (tbuf)))
298 out->qbytes = tbuf.msg_qbytes;
299 out->uid = tbuf.msg_perm.uid;
300 out->gid = tbuf.msg_perm.gid;
301 out->mode = tbuf.msg_perm.mode;
307 struct msqid_ds tbuf_old;
309 if (copy_from_user (&tbuf_old, buf, sizeof (tbuf_old)))
312 out->uid = tbuf_old.msg_perm.uid;
313 out->gid = tbuf_old.msg_perm.gid;
314 out->mode = tbuf_old.msg_perm.mode;
316 if(tbuf_old.msg_qbytes == 0)
317 out->qbytes = tbuf_old.msg_lqbytes;
319 out->qbytes = tbuf_old.msg_qbytes;
328 asmlinkage long sys_msgctl (int msqid, int cmd, struct msqid_ds __user *buf)
331 struct msg_queue *msq;
332 struct msq_setbuf setbuf;
333 struct kern_ipc_perm *ipcp;
335 if (msqid < 0 || cmd < 0)
338 version = ipc_parse_version(&cmd);
344 struct msginfo msginfo;
348 /* We must not return kernel stack data.
349 * due to padding, it's not enough
350 * to set all member fields.
353 err = security_msg_queue_msgctl(NULL, cmd);
357 memset(&msginfo,0,sizeof(msginfo));
358 msginfo.msgmni = msg_ctlmni;
359 msginfo.msgmax = msg_ctlmax;
360 msginfo.msgmnb = msg_ctlmnb;
361 msginfo.msgssz = MSGSSZ;
362 msginfo.msgseg = MSGSEG;
364 if (cmd == MSG_INFO) {
365 msginfo.msgpool = msg_ids.in_use;
366 msginfo.msgmap = atomic_read(&msg_hdrs);
367 msginfo.msgtql = atomic_read(&msg_bytes);
369 msginfo.msgmap = MSGMAP;
370 msginfo.msgpool = MSGPOOL;
371 msginfo.msgtql = MSGTQL;
373 max_id = msg_ids.max_id;
375 if (copy_to_user (buf, &msginfo, sizeof(struct msginfo)))
377 return (max_id < 0) ? 0: max_id;
382 struct msqid64_ds tbuf;
386 if(cmd == MSG_STAT && msqid >= msg_ids.entries->size)
389 memset(&tbuf,0,sizeof(tbuf));
391 msq = msg_lock(msqid);
395 if(cmd == MSG_STAT) {
396 success_return = msg_buildid(msqid, msq->q_perm.seq);
399 if (msg_checkid(msq,msqid))
404 if (ipcperms (&msq->q_perm, S_IRUGO))
407 err = security_msg_queue_msgctl(msq, cmd);
411 kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm);
412 tbuf.msg_stime = msq->q_stime;
413 tbuf.msg_rtime = msq->q_rtime;
414 tbuf.msg_ctime = msq->q_ctime;
415 tbuf.msg_cbytes = msq->q_cbytes;
416 tbuf.msg_qnum = msq->q_qnum;
417 tbuf.msg_qbytes = msq->q_qbytes;
418 tbuf.msg_lspid = msq->q_lspid;
419 tbuf.msg_lrpid = msq->q_lrpid;
421 if (copy_msqid_to_user(buf, &tbuf, version))
423 return success_return;
428 if (copy_msqid_from_user (&setbuf, buf, version))
430 if ((err = audit_ipc_perms(setbuf.qbytes, setbuf.uid, setbuf.gid, setbuf.mode)))
440 msq = msg_lock(msqid);
446 if (msg_checkid(msq,msqid))
450 if (current->euid != ipcp->cuid &&
451 current->euid != ipcp->uid && !capable(CAP_SYS_ADMIN))
452 /* We _could_ check for CAP_CHOWN above, but we don't */
455 err = security_msg_queue_msgctl(msq, cmd);
463 if (setbuf.qbytes > msg_ctlmnb && !capable(CAP_SYS_RESOURCE))
466 msq->q_qbytes = setbuf.qbytes;
468 ipcp->uid = setbuf.uid;
469 ipcp->gid = setbuf.gid;
470 ipcp->mode = (ipcp->mode & ~S_IRWXUGO) |
471 (S_IRWXUGO & setbuf.mode);
472 msq->q_ctime = get_seconds();
473 /* sleeping receivers might be excluded by
474 * stricter permissions.
476 expunge_all(msq,-EAGAIN);
477 /* sleeping senders might be able to send
478 * due to a larger queue size.
480 ss_wakeup(&msq->q_senders,0);
485 freeque (msq, msqid);
500 static int testmsg(struct msg_msg* msg,long type,int mode)
506 case SEARCH_LESSEQUAL:
507 if(msg->m_type <=type)
511 if(msg->m_type == type)
514 case SEARCH_NOTEQUAL:
515 if(msg->m_type != type)
522 static inline int pipelined_send(struct msg_queue* msq, struct msg_msg* msg)
524 struct list_head* tmp;
526 tmp = msq->q_receivers.next;
527 while (tmp != &msq->q_receivers) {
528 struct msg_receiver* msr;
529 msr = list_entry(tmp,struct msg_receiver,r_list);
531 if(testmsg(msg,msr->r_msgtype,msr->r_mode) &&
532 !security_msg_queue_msgrcv(msq, msg, msr->r_tsk, msr->r_msgtype, msr->r_mode)) {
533 list_del(&msr->r_list);
534 if(msr->r_maxsize < msg->m_ts) {
536 wake_up_process(msr->r_tsk);
538 msr->r_msg = ERR_PTR(-E2BIG);
541 msq->q_lrpid = msr->r_tsk->pid;
542 msq->q_rtime = get_seconds();
543 wake_up_process(msr->r_tsk);
553 asmlinkage long sys_msgsnd (int msqid, struct msgbuf __user *msgp, size_t msgsz, int msgflg)
555 struct msg_queue *msq;
560 if (msgsz > msg_ctlmax || (long) msgsz < 0 || msqid < 0)
562 if (get_user(mtype, &msgp->mtype))
567 msg = load_msg(msgp->mtext, msgsz);
574 msq = msg_lock(msqid);
580 if (msg_checkid(msq,msqid))
581 goto out_unlock_free;
587 if (ipcperms(&msq->q_perm, S_IWUGO))
588 goto out_unlock_free;
590 err = security_msg_queue_msgsnd(msq, msg, msgflg);
592 goto out_unlock_free;
594 if(msgsz + msq->q_cbytes <= msq->q_qbytes &&
595 1 + msq->q_qnum <= msq->q_qbytes) {
599 /* queue full, wait: */
600 if(msgflg&IPC_NOWAIT) {
602 goto out_unlock_free;
609 ipc_lock_by_ptr(&msq->q_perm);
611 if (msq->q_perm.deleted) {
613 goto out_unlock_free;
617 if (signal_pending(current)) {
619 goto out_unlock_free;
623 msq->q_lspid = current->tgid;
624 msq->q_stime = get_seconds();
626 if(!pipelined_send(msq,msg)) {
627 /* noone is waiting for this message, enqueue it */
628 list_add_tail(&msg->m_list,&msq->q_messages);
629 msq->q_cbytes += msgsz;
631 atomic_add(msgsz,&msg_bytes);
632 atomic_inc(&msg_hdrs);
646 static inline int convert_mode(long* msgtyp, int msgflg)
649 * find message of correct type.
650 * msgtyp = 0 => get first.
651 * msgtyp > 0 => get first message of matching type.
652 * msgtyp < 0 => get message with least type must be < abs(msgtype).
658 return SEARCH_LESSEQUAL;
660 if(msgflg & MSG_EXCEPT)
661 return SEARCH_NOTEQUAL;
665 asmlinkage long sys_msgrcv (int msqid, struct msgbuf __user *msgp, size_t msgsz,
666 long msgtyp, int msgflg)
668 struct msg_queue *msq;
672 if (msqid < 0 || (long) msgsz < 0)
674 mode = convert_mode(&msgtyp,msgflg);
676 msq = msg_lock(msqid);
680 msg = ERR_PTR(-EIDRM);
681 if (msg_checkid(msq,msqid))
685 struct msg_receiver msr_d;
686 struct list_head* tmp;
688 msg = ERR_PTR(-EACCES);
689 if (ipcperms (&msq->q_perm, S_IRUGO))
692 msg = ERR_PTR(-EAGAIN);
693 tmp = msq->q_messages.next;
694 while (tmp != &msq->q_messages) {
695 struct msg_msg *walk_msg;
696 walk_msg = list_entry(tmp,struct msg_msg,m_list);
697 if(testmsg(walk_msg,msgtyp,mode) &&
698 !security_msg_queue_msgrcv(msq, walk_msg, current, msgtyp, mode)) {
700 if(mode == SEARCH_LESSEQUAL && walk_msg->m_type != 1) {
702 msgtyp=walk_msg->m_type-1;
711 /* Found a suitable message. Unlink it from the queue. */
712 if ((msgsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
713 msg = ERR_PTR(-E2BIG);
716 list_del(&msg->m_list);
718 msq->q_rtime = get_seconds();
719 msq->q_lrpid = current->tgid;
720 msq->q_cbytes -= msg->m_ts;
721 atomic_sub(msg->m_ts,&msg_bytes);
722 atomic_dec(&msg_hdrs);
723 ss_wakeup(&msq->q_senders,0);
727 /* No message waiting. Wait for a message */
728 if (msgflg & IPC_NOWAIT) {
729 msg = ERR_PTR(-ENOMSG);
732 list_add_tail(&msr_d.r_list,&msq->q_receivers);
733 msr_d.r_tsk = current;
734 msr_d.r_msgtype = msgtyp;
736 if(msgflg & MSG_NOERROR)
737 msr_d.r_maxsize = INT_MAX;
739 msr_d.r_maxsize = msgsz;
740 msr_d.r_msg = ERR_PTR(-EAGAIN);
741 current->state = TASK_INTERRUPTIBLE;
746 /* Lockless receive, part 1:
747 * Disable preemption. We don't hold a reference to the queue
748 * and getting a reference would defeat the idea of a lockless
749 * operation, thus the code relies on rcu to guarantee the
751 * Prior to destruction, expunge_all(-EIRDM) changes r_msg.
752 * Thus if r_msg is -EAGAIN, then the queue not yet destroyed.
753 * rcu_read_lock() prevents preemption between reading r_msg
754 * and the spin_lock() inside ipc_lock_by_ptr().
758 /* Lockless receive, part 2:
759 * Wait until pipelined_send or expunge_all are outside of
760 * wake_up_process(). There is a race with exit(), see
761 * ipc/mqueue.c for the details.
763 msg = (struct msg_msg*) msr_d.r_msg;
764 while (msg == NULL) {
766 msg = (struct msg_msg*) msr_d.r_msg;
769 /* Lockless receive, part 3:
770 * If there is a message or an error then accept it without
773 if(msg != ERR_PTR(-EAGAIN)) {
778 /* Lockless receive, part 3:
779 * Acquire the queue spinlock.
781 ipc_lock_by_ptr(&msq->q_perm);
784 /* Lockless receive, part 4:
785 * Repeat test after acquiring the spinlock.
787 msg = (struct msg_msg*)msr_d.r_msg;
788 if(msg != ERR_PTR(-EAGAIN))
791 list_del(&msr_d.r_list);
792 if (signal_pending(current)) {
793 msg = ERR_PTR(-ERESTARTNOHAND);
802 msgsz = (msgsz > msg->m_ts) ? msg->m_ts : msgsz;
803 if (put_user (msg->m_type, &msgp->mtype) ||
804 store_msg(msgp->mtext, msg, msgsz)) {
811 #ifdef CONFIG_PROC_FS
812 static int sysvipc_msg_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data)
819 len += sprintf(buffer, " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n");
821 for(i = 0; i <= msg_ids.max_id; i++) {
822 struct msg_queue * msq;
825 if (!vx_check(msq->q_perm.xid, VX_IDENT)) {
829 len += sprintf(buffer + len, "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n",
831 msg_buildid(i,msq->q_perm.seq),
851 if(pos > offset + length)
859 *start = buffer + (offset - begin);
860 len -= (offset - begin);