/*
* linux/ipc/msg.c
* Copyright (C) 1992 Krishna Balasubramanian
*
* Removed all the remaining kerneld mess
* Catch the -EFAULT stuff properly
* Use GFP_KERNEL for messages as in 1.2
* Fixed up the unchecked user space derefs
* Copyright (C) 1998 Alan Cox & Andi Kleen
*
* /proc/sysvipc/msg support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
*
* mostly rewritten, threaded and wake-one semantics added
* MSGMAX limit removed, sysctl's added
* (c) 1999 Manfred Spraul <manfreds@colorfullife.com>
*/
#include <linux/config.h>
#include <linux/malloc.h>
#include <linux/msg.h>
#include <linux/spinlock.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/list.h>
#include <asm/uaccess.h>
#include "util.h"
/* sysctl: */
int msg_ctlmax = MSGMAX;
int msg_ctlmnb = MSGMNB;
int msg_ctlmni = MSGMNI;
/* one msg_receiver structure for each sleeping receiver */
struct msg_receiver {
struct list_head r_list;
struct task_struct* r_tsk;
int r_mode;
long r_msgtype;
long r_maxsize;
struct msg_msg* volatile r_msg;
};
/* one msg_sender for each sleeping sender */
struct msg_sender {
struct list_head list;
struct task_struct* tsk;
};
struct msg_msgseg {
struct msg_msgseg* next;
/* the next part of the message follows immediately */
};
/* one msg_msg structure for each message */
struct msg_msg {
struct list_head m_list;
long m_type;
int m_ts; /* message text size */
struct msg_msgseg* next;
/* the actual message follows immediately */
};
#define DATALEN_MSG (PAGE_SIZE-sizeof(struct msg_msg))
#define DATALEN_SEG (PAGE_SIZE-sizeof(struct msg_msgseg))
/* one msq_queue structure for each present queue on the system */
struct msg_queue {
struct kern_ipc_perm q_perm;
time_t q_stime; /* last msgsnd time */
time_t q_rtime; /* last msgrcv time */
time_t q_ctime; /* last change time */
unsigned long q_cbytes; /* current number of bytes on queue */
unsigned long q_qnum; /* number of messages in queue */
unsigned long q_qbytes; /* max number of bytes on queue */
pid_t q_lspid; /* pid of last msgsnd */
pid_t q_lrpid; /* last receive pid */
struct list_head q_messages;
struct list_head q_receivers;
struct list_head q_senders;
};
#define SEARCH_ANY 1
#define SEARCH_EQUAL 2
#define SEARCH_NOTEQUAL 3
#define SEARCH_LESSEQUAL 4
static atomic_t msg_bytes = ATOMIC_INIT(0);
static atomic_t msg_hdrs = ATOMIC_INIT(0);
static struct ipc_ids msg_ids;
#define msg_lock(id) ((struct msg_queue*)ipc_lock(&msg_ids,id))
#define msg_unlock(id) ipc_unlock(&msg_ids,id)
#define msg_rmid(id) ((struct msg_queue*)ipc_rmid(&msg_ids,id))
#define msg_checkid(msq, msgid) \
ipc_checkid(&msg_ids,&msq->q_perm,msgid)
#define msg_buildid(id, seq) \
ipc_buildid(&msg_ids, id, seq)
static void freeque (int id);
static int newque (key_t key, int msgflg);
#ifdef CONFIG_PROC_FS
static int sysvipc_msg_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data);
#endif
108 void __init msg_init (void)
{
ipc_init_ids(&msg_ids,msg_ctlmni);
#ifdef CONFIG_PROC_FS
create_proc_read_entry("sysvipc/msg", 0, 0, sysvipc_msg_read_proc, NULL);
#endif
}
117 static int newque (key_t key, int msgflg)
{
int id;
struct msg_queue *msq;
msq = (struct msg_queue *) kmalloc (sizeof (*msq), GFP_KERNEL);
123 if (!msq)
124 return -ENOMEM;
id = ipc_addid(&msg_ids, &msq->q_perm, msg_ctlmni);
126 if(id == -1) {
kfree(msq);
128 return -ENOSPC;
}
msq->q_perm.mode = (msgflg & S_IRWXUGO);
msq->q_perm.key = key;
msq->q_stime = msq->q_rtime = 0;
msq->q_ctime = CURRENT_TIME;
msq->q_cbytes = msq->q_qnum = 0;
msq->q_qbytes = msg_ctlmnb;
msq->q_lspid = msq->q_lrpid = 0;
138 INIT_LIST_HEAD(&msq->q_messages);
139 INIT_LIST_HEAD(&msq->q_receivers);
140 INIT_LIST_HEAD(&msq->q_senders);
msg_unlock(id);
143 return msg_buildid(id,msq->q_perm.seq);
}
146 static void free_msg(struct msg_msg* msg)
{
struct msg_msgseg* seg;
seg = msg->next;
kfree(msg);
151 while(seg != NULL) {
struct msg_msgseg* tmp = seg->next;
kfree(seg);
seg = tmp;
}
}
158 static struct msg_msg* load_msg(void* src, int len)
{
struct msg_msg* msg;
struct msg_msgseg** pseg;
int err;
int alen;
alen = len;
166 if(alen > DATALEN_MSG)
alen = DATALEN_MSG;
msg = (struct msg_msg *) kmalloc (sizeof(*msg) + alen, GFP_KERNEL);
170 if(msg==NULL)
171 return ERR_PTR(-ENOMEM);
msg->next = NULL;
175 if (copy_from_user(msg+1, src, alen)) {
err = -EFAULT;
177 goto out_err;
}
len -= alen;
src = ((char*)src)+alen;
pseg = &msg->next;
183 while(len > 0) {
struct msg_msgseg* seg;
alen = len;
186 if(alen > DATALEN_SEG)
alen = DATALEN_SEG;
seg = (struct msg_msgseg *) kmalloc (sizeof(*seg) + alen, GFP_KERNEL);
189 if(seg==NULL) {
err=-ENOMEM;
191 goto out_err;
}
*pseg = seg;
seg->next = NULL;
195 if(copy_from_user (seg+1, src, alen)) {
err = -EFAULT;
197 goto out_err;
}
pseg = &seg->next;
len -= alen;
src = ((char*)src)+alen;
}
203 return msg;
out_err:
free_msg(msg);
207 return ERR_PTR(err);
}
210 static int store_msg(void* dest, struct msg_msg* msg, int len)
{
int alen;
struct msg_msgseg *seg;
alen = len;
216 if(alen > DATALEN_MSG)
alen = DATALEN_MSG;
218 if(copy_to_user (dest, msg+1, alen))
219 return -1;
len -= alen;
dest = ((char*)dest)+alen;
seg = msg->next;
224 while(len > 0) {
alen = len;
226 if(alen > DATALEN_SEG)
alen = DATALEN_SEG;
228 if(copy_to_user (dest, seg+1, alen))
229 return -1;
len -= alen;
dest = ((char*)dest)+alen;
seg=seg->next;
}
234 return 0;
}
237 static inline void ss_add(struct msg_queue* msq, struct msg_sender* mss)
{
mss->tsk=current;
current->state=TASK_INTERRUPTIBLE;
list_add_tail(&mss->list,&msq->q_senders);
}
244 static inline void ss_del(struct msg_sender* mss)
{
246 if(mss->list.next != NULL)
list_del(&mss->list);
}
250 static void ss_wakeup(struct list_head* h, int kill)
{
struct list_head *tmp;
tmp = h->next;
255 while (tmp != h) {
struct msg_sender* mss;
mss = list_entry(tmp,struct msg_sender,list);
tmp = tmp->next;
260 if(kill)
mss->list.next=NULL;
wake_up_process(mss->tsk);
}
}
266 static void expunge_all(struct msg_queue* msq, int res)
{
struct list_head *tmp;
tmp = msq->q_receivers.next;
271 while (tmp != &msq->q_receivers) {
struct msg_receiver* msr;
msr = list_entry(tmp,struct msg_receiver,r_list);
tmp = tmp->next;
msr->r_msg = ERR_PTR(res);
wake_up_process(msr->r_tsk);
}
}
281 static void freeque (int id)
{
struct msg_queue *msq;
struct list_head *tmp;
msq = msg_rmid(id);
expunge_all(msq,-EIDRM);
ss_wakeup(&msq->q_senders,1);
msg_unlock(id);
tmp = msq->q_messages.next;
293 while(tmp != &msq->q_messages) {
struct msg_msg* msg = list_entry(tmp,struct msg_msg,m_list);
tmp = tmp->next;
atomic_dec(&msg_hdrs);
free_msg(msg);
}
atomic_sub(msq->q_cbytes, &msg_bytes);
kfree(msq);
}
303 asmlinkage long sys_msgget (key_t key, int msgflg)
{
int id, ret = -EPERM;
struct msg_queue *msq;
down(&msg_ids.sem);
309 if (key == IPC_PRIVATE)
ret = newque(key, msgflg);
311 else if ((id = ipc_findkey(&msg_ids, key)) == -1) { /* key not used */
312 if (!(msgflg & IPC_CREAT))
ret = -ENOENT;
314 else
ret = newque(key, msgflg);
316 } else if (msgflg & IPC_CREAT && msgflg & IPC_EXCL) {
ret = -EEXIST;
318 } else {
msq = msg_lock(id);
320 if(msq==NULL)
321 BUG();
322 if (ipcperms(&msq->q_perm, msgflg))
ret = -EACCES;
324 else
ret = msg_buildid(id, msq->q_perm.seq);
msg_unlock(id);
}
up(&msg_ids.sem);
329 return ret;
}
332 static inline unsigned long copy_msqid_to_user(void *buf, struct msqid64_ds *in, int version)
{
334 switch(version) {
335 case IPC_64:
336 return copy_to_user (buf, in, sizeof(*in));
337 case IPC_OLD:
{
struct msqid_ds out;
memset(&out,0,sizeof(out));
ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm);
out.msg_stime = in->msg_stime;
out.msg_rtime = in->msg_rtime;
out.msg_ctime = in->msg_ctime;
349 if(in->msg_cbytes > USHRT_MAX)
out.msg_cbytes = USHRT_MAX;
351 else
out.msg_cbytes = in->msg_cbytes;
out.msg_lcbytes = in->msg_cbytes;
355 if(in->msg_qnum > USHRT_MAX)
out.msg_qnum = USHRT_MAX;
357 else
out.msg_qnum = in->msg_qnum;
360 if(in->msg_qbytes > USHRT_MAX)
out.msg_qbytes = USHRT_MAX;
362 else
out.msg_qbytes = in->msg_qbytes;
out.msg_lqbytes = in->msg_qbytes;
out.msg_lspid = in->msg_lspid;
out.msg_lrpid = in->msg_lrpid;
369 return copy_to_user (buf, &out, sizeof(out));
}
371 default:
372 return -EINVAL;
}
}
struct msq_setbuf {
unsigned long qbytes;
uid_t uid;
gid_t gid;
mode_t mode;
};
383 static inline unsigned long copy_msqid_from_user(struct msq_setbuf *out, void *buf, int version)
{
385 switch(version) {
386 case IPC_64:
{
struct msqid64_ds tbuf;
390 if (copy_from_user (&tbuf, buf, sizeof (tbuf)))
391 return -EFAULT;
out->qbytes = tbuf.msg_qbytes;
out->uid = tbuf.msg_perm.uid;
out->gid = tbuf.msg_perm.gid;
out->mode = tbuf.msg_perm.mode;
398 return 0;
}
400 case IPC_OLD:
{
struct msqid_ds tbuf_old;
404 if (copy_from_user (&tbuf_old, buf, sizeof (tbuf_old)))
405 return -EFAULT;
out->uid = tbuf_old.msg_perm.uid;
out->gid = tbuf_old.msg_perm.gid;
out->mode = tbuf_old.msg_perm.mode;
411 if(tbuf_old.msg_qbytes == 0)
out->qbytes = tbuf_old.msg_lqbytes;
413 else
out->qbytes = tbuf_old.msg_qbytes;
416 return 0;
}
418 default:
419 return -EINVAL;
}
}
423 asmlinkage long sys_msgctl (int msqid, int cmd, struct msqid_ds *buf)
{
int err, version;
struct msg_queue *msq;
struct msq_setbuf setbuf;
struct kern_ipc_perm *ipcp;
430 if (msqid < 0 || cmd < 0)
431 return -EINVAL;
version = ipc_parse_version(&cmd);
435 switch (cmd) {
436 case IPC_INFO:
437 case MSG_INFO:
{
struct msginfo msginfo;
int max_id;
441 if (!buf)
442 return -EFAULT;
/* We must not return kernel stack data.
* due to padding, it's not enough
* to set all member fields.
*/
memset(&msginfo,0,sizeof(msginfo));
msginfo.msgmni = msg_ctlmni;
msginfo.msgmax = msg_ctlmax;
msginfo.msgmnb = msg_ctlmnb;
msginfo.msgssz = MSGSSZ;
msginfo.msgseg = MSGSEG;
down(&msg_ids.sem);
454 if (cmd == MSG_INFO) {
msginfo.msgpool = msg_ids.in_use;
msginfo.msgmap = atomic_read(&msg_hdrs);
msginfo.msgtql = atomic_read(&msg_bytes);
458 } else {
msginfo.msgmap = MSGMAP;
msginfo.msgpool = MSGPOOL;
msginfo.msgtql = MSGTQL;
}
max_id = msg_ids.max_id;
up(&msg_ids.sem);
465 if (copy_to_user (buf, &msginfo, sizeof(struct msginfo)))
466 return -EFAULT;
467 return (max_id < 0) ? 0: max_id;
}
469 case MSG_STAT:
470 case IPC_STAT:
{
struct msqid64_ds tbuf;
int success_return;
474 if (!buf)
475 return -EFAULT;
476 if(cmd == MSG_STAT && msqid > msg_ids.size)
477 return -EINVAL;
memset(&tbuf,0,sizeof(tbuf));
msq = msg_lock(msqid);
482 if (msq == NULL)
483 return -EINVAL;
485 if(cmd == MSG_STAT) {
success_return = msg_buildid(msqid, msq->q_perm.seq);
487 } else {
err = -EIDRM;
489 if (msg_checkid(msq,msqid))
490 goto out_unlock;
success_return = 0;
}
err = -EACCES;
494 if (ipcperms (&msq->q_perm, S_IRUGO))
495 goto out_unlock;
kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm);
tbuf.msg_stime = msq->q_stime;
tbuf.msg_rtime = msq->q_rtime;
tbuf.msg_ctime = msq->q_ctime;
tbuf.msg_cbytes = msq->q_cbytes;
tbuf.msg_qnum = msq->q_qnum;
tbuf.msg_qbytes = msq->q_qbytes;
tbuf.msg_lspid = msq->q_lspid;
tbuf.msg_lrpid = msq->q_lrpid;
msg_unlock(msqid);
507 if (copy_msqid_to_user(buf, &tbuf, version))
508 return -EFAULT;
509 return success_return;
}
511 case IPC_SET:
512 if (!buf)
513 return -EFAULT;
514 if (copy_msqid_from_user (&setbuf, buf, version))
515 return -EFAULT;
516 break;
517 case IPC_RMID:
518 break;
519 default:
520 return -EINVAL;
}
down(&msg_ids.sem);
msq = msg_lock(msqid);
err=-EINVAL;
526 if (msq == NULL)
527 goto out_up;
err = -EIDRM;
530 if (msg_checkid(msq,msqid))
531 goto out_unlock_up;
ipcp = &msq->q_perm;
err = -EPERM;
if (current->euid != ipcp->cuid &&
535 current->euid != ipcp->uid && !capable(CAP_SYS_ADMIN))
/* We _could_ check for CAP_CHOWN above, but we don't */
537 goto out_unlock_up;
539 switch (cmd) {
540 case IPC_SET:
{
542 if (setbuf.qbytes > msg_ctlmnb && !capable(CAP_SYS_RESOURCE))
543 goto out_unlock_up;
msq->q_qbytes = setbuf.qbytes;
ipcp->uid = setbuf.uid;
ipcp->gid = setbuf.gid;
ipcp->mode = (ipcp->mode & ~S_IRWXUGO) |
(S_IRWXUGO & setbuf.mode);
msq->q_ctime = CURRENT_TIME;
/* sleeping receivers might be excluded by
* stricter permissions.
*/
expunge_all(msq,-EAGAIN);
/* sleeping senders might be able to send
* due to a larger queue size.
*/
ss_wakeup(&msq->q_senders,0);
msg_unlock(msqid);
560 break;
}
562 case IPC_RMID:
freeque (msqid);
564 break;
}
err = 0;
out_up:
up(&msg_ids.sem);
569 return err;
out_unlock_up:
msg_unlock(msqid);
572 goto out_up;
out_unlock:
msg_unlock(msqid);
575 return err;
}
578 static int testmsg(struct msg_msg* msg,long type,int mode)
{
580 switch(mode)
{
582 case SEARCH_ANY:
583 return 1;
584 case SEARCH_LESSEQUAL:
585 if(msg->m_type <=type)
586 return 1;
587 break;
588 case SEARCH_EQUAL:
589 if(msg->m_type == type)
590 return 1;
591 break;
592 case SEARCH_NOTEQUAL:
593 if(msg->m_type != type)
594 return 1;
595 break;
}
597 return 0;
}
600 int inline pipelined_send(struct msg_queue* msq, struct msg_msg* msg)
{
struct list_head* tmp;
tmp = msq->q_receivers.next;
605 while (tmp != &msq->q_receivers) {
struct msg_receiver* msr;
msr = list_entry(tmp,struct msg_receiver,r_list);
tmp = tmp->next;
609 if(testmsg(msg,msr->r_msgtype,msr->r_mode)) {
list_del(&msr->r_list);
611 if(msr->r_maxsize < msg->m_ts) {
msr->r_msg = ERR_PTR(-E2BIG);
wake_up_process(msr->r_tsk);
614 } else {
msr->r_msg = msg;
msq->q_lspid = msr->r_tsk->pid;
msq->q_rtime = CURRENT_TIME;
wake_up_process(msr->r_tsk);
619 return 1;
}
}
}
623 return 0;
}
626 asmlinkage long sys_msgsnd (int msqid, struct msgbuf *msgp, size_t msgsz, int msgflg)
{
struct msg_queue *msq;
struct msg_msg *msg;
long mtype;
int err;
633 if (msgsz > msg_ctlmax || (long) msgsz < 0 || msqid < 0)
634 return -EINVAL;
635 if (get_user(mtype, &msgp->mtype))
636 return -EFAULT;
637 if (mtype < 1)
638 return -EINVAL;
msg = load_msg(msgp->mtext, msgsz);
641 if(IS_ERR(msg))
642 return PTR_ERR(msg);
msg->m_type = mtype;
msg->m_ts = msgsz;
msq = msg_lock(msqid);
err=-EINVAL;
649 if(msq==NULL)
650 goto out_free;
retry:
err= -EIDRM;
653 if (msg_checkid(msq,msqid))
654 goto out_unlock_free;
err=-EACCES;
657 if (ipcperms(&msq->q_perm, S_IWUGO))
658 goto out_unlock_free;
if(msgsz + msq->q_cbytes > msq->q_qbytes ||
661 1 + msq->q_qnum > msq->q_qbytes) {
struct msg_sender s;
664 if(msgflg&IPC_NOWAIT) {
err=-EAGAIN;
666 goto out_unlock_free;
}
ss_add(msq, &s);
msg_unlock(msqid);
schedule();
current->state= TASK_RUNNING;
msq = msg_lock(msqid);
err = -EIDRM;
675 if(msq==NULL)
676 goto out_free;
ss_del(&s);
679 if (signal_pending(current)) {
err=-EINTR;
681 goto out_unlock_free;
}
683 goto retry;
}
686 if(!pipelined_send(msq,msg)) {
/* noone is waiting for this message, enqueue it */
list_add_tail(&msg->m_list,&msq->q_messages);
msq->q_cbytes += msgsz;
msq->q_qnum++;
atomic_add(msgsz,&msg_bytes);
atomic_inc(&msg_hdrs);
}
err = 0;
msg = NULL;
msq->q_lspid = current->pid;
msq->q_stime = CURRENT_TIME;
out_unlock_free:
msg_unlock(msqid);
out_free:
703 if(msg!=NULL)
free_msg(msg);
705 return err;
}
708 int inline convert_mode(long* msgtyp, int msgflg)
{
/*
* 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).
*/
716 if(*msgtyp==0)
717 return SEARCH_ANY;
718 if(*msgtyp<0) {
*msgtyp=-(*msgtyp);
720 return SEARCH_LESSEQUAL;
}
722 if(msgflg & MSG_EXCEPT)
723 return SEARCH_NOTEQUAL;
724 return SEARCH_EQUAL;
}
727 asmlinkage long sys_msgrcv (int msqid, struct msgbuf *msgp, size_t msgsz,
long msgtyp, int msgflg)
{
struct msg_queue *msq;
struct msg_receiver msr_d;
struct list_head* tmp;
struct msg_msg* msg, *found_msg;
int err;
int mode;
737 if (msqid < 0 || (long) msgsz < 0)
738 return -EINVAL;
mode = convert_mode(&msgtyp,msgflg);
msq = msg_lock(msqid);
742 if(msq==NULL)
743 return -EINVAL;
retry:
err=-EACCES;
746 if (ipcperms (&msq->q_perm, S_IRUGO))
747 goto out_unlock;
tmp = msq->q_messages.next;
found_msg=NULL;
751 while (tmp != &msq->q_messages) {
msg = list_entry(tmp,struct msg_msg,m_list);
753 if(testmsg(msg,msgtyp,mode)) {
found_msg = msg;
755 if(mode == SEARCH_LESSEQUAL && msg->m_type != 1) {
found_msg=msg;
msgtyp=msg->m_type-1;
758 } else {
found_msg=msg;
760 break;
}
}
tmp = tmp->next;
}
765 if(found_msg) {
msg=found_msg;
767 if ((msgsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
err=-E2BIG;
769 goto out_unlock;
}
list_del(&msg->m_list);
msq->q_qnum--;
msq->q_rtime = CURRENT_TIME;
msq->q_lrpid = current->pid;
msq->q_cbytes -= msg->m_ts;
atomic_sub(msg->m_ts,&msg_bytes);
atomic_dec(&msg_hdrs);
ss_wakeup(&msq->q_senders,0);
msg_unlock(msqid);
out_success:
msgsz = (msgsz > msg->m_ts) ? msg->m_ts : msgsz;
if (put_user (msg->m_type, &msgp->mtype) ||
783 store_msg(msgp->mtext, msg, msgsz)) {
msgsz = -EFAULT;
}
free_msg(msg);
787 return msgsz;
788 } else
{
struct msg_queue *t;
/* no message waiting. Prepare for pipelined
* receive.
*/
794 if (msgflg & IPC_NOWAIT) {
err=-ENOMSG;
796 goto out_unlock;
}
list_add_tail(&msr_d.r_list,&msq->q_receivers);
msr_d.r_tsk = current;
msr_d.r_msgtype = msgtyp;
msr_d.r_mode = mode;
802 if(msgflg & MSG_NOERROR)
msr_d.r_maxsize = INT_MAX;
804 else
msr_d.r_maxsize = msgsz;
msr_d.r_msg = ERR_PTR(-EAGAIN);
current->state = TASK_INTERRUPTIBLE;
msg_unlock(msqid);
schedule();
current->state = TASK_RUNNING;
msg = (struct msg_msg*) msr_d.r_msg;
814 if(!IS_ERR(msg))
815 goto out_success;
t = msg_lock(msqid);
818 if(t==NULL)
msqid=-1;
msg = (struct msg_msg*)msr_d.r_msg;
821 if(!IS_ERR(msg)) {
/* our message arived while we waited for
* the spinlock. Process it.
*/
825 if(msqid!=-1)
msg_unlock(msqid);
827 goto out_success;
}
err = PTR_ERR(msg);
830 if(err == -EAGAIN) {
831 if(msqid==-1)
832 BUG();
list_del(&msr_d.r_list);
834 if (signal_pending(current))
err=-EINTR;
836 else
837 goto retry;
}
}
out_unlock:
841 if(msqid!=-1)
msg_unlock(msqid);
843 return err;
}
#ifdef CONFIG_PROC_FS
847 static int sysvipc_msg_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data)
{
off_t pos = 0;
off_t begin = 0;
int i, len = 0;
down(&msg_ids.sem);
len += sprintf(buffer, " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n");
856 for(i = 0; i <= msg_ids.max_id; i++) {
struct msg_queue * msq;
msq = msg_lock(i);
859 if(msq != NULL) {
len += sprintf(buffer + len, "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n",
msq->q_perm.key,
msg_buildid(i,msq->q_perm.seq),
msq->q_perm.mode,
msq->q_cbytes,
msq->q_qnum,
msq->q_lspid,
msq->q_lrpid,
msq->q_perm.uid,
msq->q_perm.gid,
msq->q_perm.cuid,
msq->q_perm.cgid,
msq->q_stime,
msq->q_rtime,
msq->q_ctime);
msg_unlock(i);
pos += len;
878 if(pos < offset) {
len = 0;
begin = pos;
}
882 if(pos > offset + length)
883 goto done;
}
}
*eof = 1;
done:
up(&msg_ids.sem);
*start = buffer + (offset - begin);
len -= (offset - begin);
892 if(len > length)
len = length;
894 if(len < 0)
len = 0;
896 return len;
}
#endif