1150 lines
27 KiB
C
1150 lines
27 KiB
C
/* $FreeBSD$ */
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/*
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* Implementation of SVID messages
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*
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* Author: Daniel Boulet
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*
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* Copyright 1993 Daniel Boulet and RTMX Inc.
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*
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* This system call was implemented by Daniel Boulet under contract from RTMX.
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*
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* Redistribution and use in source forms, with and without modification,
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* are permitted provided that this entire comment appears intact.
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*
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* Redistribution in binary form may occur without any restrictions.
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* Obviously, it would be nice if you gave credit where credit is due
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* but requiring it would be too onerous.
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*
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* This software is provided ``AS IS'' without any warranties of any kind.
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*/
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#include "opt_sysvipc.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/sysproto.h>
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#include <sys/kernel.h>
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#include <sys/proc.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/msg.h>
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#include <sys/syscall.h>
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#include <sys/sysent.h>
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#include <sys/sysctl.h>
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#include <sys/malloc.h>
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#include <sys/jail.h>
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static MALLOC_DEFINE(M_MSG, "msg", "SVID compatible message queues");
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static void msginit(void);
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static int msgunload(void);
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static int sysvmsg_modload(struct module *, int, void *);
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#ifdef MSG_DEBUG
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#define DPRINTF(a) printf a
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#else
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#define DPRINTF(a)
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#endif
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static void msg_freehdr(struct msg *msghdr);
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/* XXX casting to (sy_call_t *) is bogus, as usual. */
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static sy_call_t *msgcalls[] = {
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(sy_call_t *)msgctl, (sy_call_t *)msgget,
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(sy_call_t *)msgsnd, (sy_call_t *)msgrcv
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};
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struct msg {
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struct msg *msg_next; /* next msg in the chain */
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long msg_type; /* type of this message */
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/* >0 -> type of this message */
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/* 0 -> free header */
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u_short msg_ts; /* size of this message */
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short msg_spot; /* location of start of msg in buffer */
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};
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#ifndef MSGSSZ
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#define MSGSSZ 8 /* Each segment must be 2^N long */
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#endif
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#ifndef MSGSEG
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#define MSGSEG 2048 /* must be less than 32767 */
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#endif
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#define MSGMAX (MSGSSZ*MSGSEG)
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#ifndef MSGMNB
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#define MSGMNB 2048 /* max # of bytes in a queue */
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#endif
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#ifndef MSGMNI
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#define MSGMNI 40
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#endif
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#ifndef MSGTQL
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#define MSGTQL 40
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#endif
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/*
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* Based on the configuration parameters described in an SVR2 (yes, two)
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* config(1m) man page.
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*
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* Each message is broken up and stored in segments that are msgssz bytes
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* long. For efficiency reasons, this should be a power of two. Also,
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* it doesn't make sense if it is less than 8 or greater than about 256.
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* Consequently, msginit in kern/sysv_msg.c checks that msgssz is a power of
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* two between 8 and 1024 inclusive (and panic's if it isn't).
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*/
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struct msginfo msginfo = {
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MSGMAX, /* max chars in a message */
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MSGMNI, /* # of message queue identifiers */
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MSGMNB, /* max chars in a queue */
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MSGTQL, /* max messages in system */
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MSGSSZ, /* size of a message segment */
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/* (must be small power of 2 greater than 4) */
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MSGSEG /* number of message segments */
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};
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/*
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* macros to convert between msqid_ds's and msqid's.
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* (specific to this implementation)
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*/
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#define MSQID(ix,ds) ((ix) & 0xffff | (((ds).msg_perm.seq << 16) & 0xffff0000))
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#define MSQID_IX(id) ((id) & 0xffff)
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#define MSQID_SEQ(id) (((id) >> 16) & 0xffff)
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/*
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* The rest of this file is specific to this particular implementation.
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*/
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struct msgmap {
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short next; /* next segment in buffer */
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/* -1 -> available */
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/* 0..(MSGSEG-1) -> index of next segment */
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};
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#define MSG_LOCKED 01000 /* Is this msqid_ds locked? */
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static int nfree_msgmaps; /* # of free map entries */
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static short free_msgmaps; /* head of linked list of free map entries */
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static struct msg *free_msghdrs;/* list of free msg headers */
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static char *msgpool; /* MSGMAX byte long msg buffer pool */
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static struct msgmap *msgmaps; /* MSGSEG msgmap structures */
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static struct msg *msghdrs; /* MSGTQL msg headers */
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static struct msqid_ds *msqids; /* MSGMNI msqid_ds struct's */
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static struct mtx msq_mtx; /* global mutex for message queues. */
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static void
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msginit()
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{
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register int i;
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TUNABLE_INT_FETCH("kern.ipc.msgseg", &msginfo.msgseg);
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TUNABLE_INT_FETCH("kern.ipc.msgssz", &msginfo.msgssz);
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msginfo.msgmax = msginfo.msgseg * msginfo.msgssz;
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TUNABLE_INT_FETCH("kern.ipc.msgmni", &msginfo.msgmni);
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msgpool = malloc(msginfo.msgmax, M_MSG, 0);
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if (msgpool == NULL)
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panic("msgpool is NULL");
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msgmaps = malloc(sizeof(struct msgmap) * msginfo.msgseg, M_MSG, 0);
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if (msgmaps == NULL)
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panic("msgmaps is NULL");
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msghdrs = malloc(sizeof(struct msg) * msginfo.msgtql, M_MSG, 0);
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if (msghdrs == NULL)
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panic("msghdrs is NULL");
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msqids = malloc(sizeof(struct msqid_ds) * msginfo.msgmni, M_MSG, 0);
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if (msqids == NULL)
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panic("msqids is NULL");
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/*
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* msginfo.msgssz should be a power of two for efficiency reasons.
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* It is also pretty silly if msginfo.msgssz is less than 8
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* or greater than about 256 so ...
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*/
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i = 8;
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while (i < 1024 && i != msginfo.msgssz)
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i <<= 1;
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if (i != msginfo.msgssz) {
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DPRINTF(("msginfo.msgssz=%d (0x%x)\n", msginfo.msgssz,
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msginfo.msgssz));
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panic("msginfo.msgssz not a small power of 2");
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}
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if (msginfo.msgseg > 32767) {
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DPRINTF(("msginfo.msgseg=%d\n", msginfo.msgseg));
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panic("msginfo.msgseg > 32767");
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}
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if (msgmaps == NULL)
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panic("msgmaps is NULL");
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for (i = 0; i < msginfo.msgseg; i++) {
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if (i > 0)
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msgmaps[i-1].next = i;
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msgmaps[i].next = -1; /* implies entry is available */
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}
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free_msgmaps = 0;
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nfree_msgmaps = msginfo.msgseg;
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if (msghdrs == NULL)
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panic("msghdrs is NULL");
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for (i = 0; i < msginfo.msgtql; i++) {
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msghdrs[i].msg_type = 0;
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if (i > 0)
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msghdrs[i-1].msg_next = &msghdrs[i];
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msghdrs[i].msg_next = NULL;
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}
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free_msghdrs = &msghdrs[0];
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if (msqids == NULL)
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panic("msqids is NULL");
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for (i = 0; i < msginfo.msgmni; i++) {
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msqids[i].msg_qbytes = 0; /* implies entry is available */
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msqids[i].msg_perm.seq = 0; /* reset to a known value */
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msqids[i].msg_perm.mode = 0;
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}
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mtx_init(&msq_mtx, "msq", NULL, MTX_DEF);
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}
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static int
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msgunload()
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{
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struct msqid_ds *msqptr;
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int msqid;
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for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
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/*
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* Look for an unallocated and unlocked msqid_ds.
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* msqid_ds's can be locked by msgsnd or msgrcv while
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* they are copying the message in/out. We can't
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* re-use the entry until they release it.
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*/
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msqptr = &msqids[msqid];
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if (msqptr->msg_qbytes != 0 ||
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(msqptr->msg_perm.mode & MSG_LOCKED) != 0)
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break;
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}
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if (msqid != msginfo.msgmni)
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return (EBUSY);
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free(msgpool, M_MSG);
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free(msgmaps, M_MSG);
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free(msghdrs, M_MSG);
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free(msqids, M_MSG);
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mtx_destroy(&msq_mtx);
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return (0);
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}
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static int
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sysvmsg_modload(struct module *module, int cmd, void *arg)
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{
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int error = 0;
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switch (cmd) {
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case MOD_LOAD:
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msginit();
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break;
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case MOD_UNLOAD:
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error = msgunload();
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break;
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case MOD_SHUTDOWN:
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break;
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default:
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error = EINVAL;
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break;
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}
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return (error);
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}
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static moduledata_t sysvmsg_mod = {
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"sysvmsg",
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&sysvmsg_modload,
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NULL
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};
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SYSCALL_MODULE_HELPER(msgsys);
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SYSCALL_MODULE_HELPER(msgctl);
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SYSCALL_MODULE_HELPER(msgget);
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SYSCALL_MODULE_HELPER(msgsnd);
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SYSCALL_MODULE_HELPER(msgrcv);
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DECLARE_MODULE(sysvmsg, sysvmsg_mod,
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SI_SUB_SYSV_MSG, SI_ORDER_FIRST);
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MODULE_VERSION(sysvmsg, 1);
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/*
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* Entry point for all MSG calls
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*
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* MPSAFE
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*/
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int
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msgsys(td, uap)
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struct thread *td;
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/* XXX actually varargs. */
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struct msgsys_args /* {
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u_int which;
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int a2;
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int a3;
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int a4;
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int a5;
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int a6;
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} */ *uap;
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{
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int error;
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if (!jail_sysvipc_allowed && jailed(td->td_ucred))
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return (ENOSYS);
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if (uap->which >= sizeof(msgcalls)/sizeof(msgcalls[0]))
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return (EINVAL);
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error = (*msgcalls[uap->which])(td, &uap->a2);
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return (error);
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}
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static void
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msg_freehdr(msghdr)
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struct msg *msghdr;
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{
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while (msghdr->msg_ts > 0) {
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short next;
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if (msghdr->msg_spot < 0 || msghdr->msg_spot >= msginfo.msgseg)
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panic("msghdr->msg_spot out of range");
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next = msgmaps[msghdr->msg_spot].next;
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msgmaps[msghdr->msg_spot].next = free_msgmaps;
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free_msgmaps = msghdr->msg_spot;
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nfree_msgmaps++;
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msghdr->msg_spot = next;
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if (msghdr->msg_ts >= msginfo.msgssz)
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msghdr->msg_ts -= msginfo.msgssz;
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else
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msghdr->msg_ts = 0;
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}
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if (msghdr->msg_spot != -1)
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panic("msghdr->msg_spot != -1");
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msghdr->msg_next = free_msghdrs;
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free_msghdrs = msghdr;
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}
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#ifndef _SYS_SYSPROTO_H_
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struct msgctl_args {
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int msqid;
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int cmd;
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struct msqid_ds *buf;
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};
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#endif
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/*
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* MPSAFE
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*/
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int
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msgctl(td, uap)
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struct thread *td;
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register struct msgctl_args *uap;
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{
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int msqid = uap->msqid;
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int cmd = uap->cmd;
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struct msqid_ds *user_msqptr = uap->buf;
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int rval, error;
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struct msqid_ds msqbuf;
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register struct msqid_ds *msqptr;
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DPRINTF(("call to msgctl(%d, %d, 0x%x)\n", msqid, cmd, user_msqptr));
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if (!jail_sysvipc_allowed && jailed(td->td_ucred))
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return (ENOSYS);
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msqid = IPCID_TO_IX(msqid);
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if (msqid < 0 || msqid >= msginfo.msgmni) {
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DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqid,
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msginfo.msgmni));
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return (EINVAL);
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}
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if (cmd == IPC_SET &&
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(error = copyin(user_msqptr, &msqbuf, sizeof(msqbuf))) != 0)
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return (error);
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msqptr = &msqids[msqid];
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mtx_lock(&msq_mtx);
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if (msqptr->msg_qbytes == 0) {
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DPRINTF(("no such msqid\n"));
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error = EINVAL;
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goto done2;
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}
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if (msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) {
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DPRINTF(("wrong sequence number\n"));
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error = EINVAL;
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goto done2;
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}
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error = 0;
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rval = 0;
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switch (cmd) {
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case IPC_RMID:
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{
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struct msg *msghdr;
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if ((error = ipcperm(td, &msqptr->msg_perm, IPC_M)))
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goto done2;
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/* Free the message headers */
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msghdr = msqptr->msg_first;
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while (msghdr != NULL) {
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struct msg *msghdr_tmp;
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/* Free the segments of each message */
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msqptr->msg_cbytes -= msghdr->msg_ts;
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msqptr->msg_qnum--;
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msghdr_tmp = msghdr;
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msghdr = msghdr->msg_next;
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msg_freehdr(msghdr_tmp);
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}
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if (msqptr->msg_cbytes != 0)
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panic("msg_cbytes is screwed up");
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if (msqptr->msg_qnum != 0)
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panic("msg_qnum is screwed up");
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msqptr->msg_qbytes = 0; /* Mark it as free */
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wakeup(msqptr);
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}
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break;
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case IPC_SET:
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if ((error = ipcperm(td, &msqptr->msg_perm, IPC_M)))
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goto done2;
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if (msqbuf.msg_qbytes > msqptr->msg_qbytes) {
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error = suser(td);
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if (error)
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goto done2;
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}
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if (msqbuf.msg_qbytes > msginfo.msgmnb) {
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DPRINTF(("can't increase msg_qbytes beyond %d"
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"(truncating)\n", msginfo.msgmnb));
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msqbuf.msg_qbytes = msginfo.msgmnb; /* silently restrict qbytes to system limit */
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}
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if (msqbuf.msg_qbytes == 0) {
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DPRINTF(("can't reduce msg_qbytes to 0\n"));
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error = EINVAL; /* non-standard errno! */
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goto done2;
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}
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msqptr->msg_perm.uid = msqbuf.msg_perm.uid; /* change the owner */
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msqptr->msg_perm.gid = msqbuf.msg_perm.gid; /* change the owner */
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msqptr->msg_perm.mode = (msqptr->msg_perm.mode & ~0777) |
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(msqbuf.msg_perm.mode & 0777);
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msqptr->msg_qbytes = msqbuf.msg_qbytes;
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msqptr->msg_ctime = time_second;
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break;
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|
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case IPC_STAT:
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if ((error = ipcperm(td, &msqptr->msg_perm, IPC_R))) {
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DPRINTF(("requester doesn't have read access\n"));
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goto done2;
|
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}
|
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break;
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|
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default:
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DPRINTF(("invalid command %d\n", cmd));
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error = EINVAL;
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goto done2;
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}
|
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|
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if (error == 0)
|
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td->td_retval[0] = rval;
|
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done2:
|
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mtx_unlock(&msq_mtx);
|
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if (cmd == IPC_STAT && error == 0)
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error = copyout(msqptr, user_msqptr, sizeof(struct msqid_ds));
|
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return(error);
|
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}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
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struct msgget_args {
|
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key_t key;
|
|
int msgflg;
|
|
};
|
|
#endif
|
|
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
int
|
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msgget(td, uap)
|
|
struct thread *td;
|
|
register struct msgget_args *uap;
|
|
{
|
|
int msqid, error = 0;
|
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int key = uap->key;
|
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int msgflg = uap->msgflg;
|
|
struct ucred *cred = td->td_ucred;
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register struct msqid_ds *msqptr = NULL;
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|
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DPRINTF(("msgget(0x%x, 0%o)\n", key, msgflg));
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|
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if (!jail_sysvipc_allowed && jailed(td->td_ucred))
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return (ENOSYS);
|
|
|
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mtx_lock(&msq_mtx);
|
|
if (key != IPC_PRIVATE) {
|
|
for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
|
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msqptr = &msqids[msqid];
|
|
if (msqptr->msg_qbytes != 0 &&
|
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msqptr->msg_perm.key == key)
|
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break;
|
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}
|
|
if (msqid < msginfo.msgmni) {
|
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DPRINTF(("found public key\n"));
|
|
if ((msgflg & IPC_CREAT) && (msgflg & IPC_EXCL)) {
|
|
DPRINTF(("not exclusive\n"));
|
|
error = EEXIST;
|
|
goto done2;
|
|
}
|
|
if ((error = ipcperm(td, &msqptr->msg_perm, msgflg & 0700 ))) {
|
|
DPRINTF(("requester doesn't have 0%o access\n",
|
|
msgflg & 0700));
|
|
goto done2;
|
|
}
|
|
goto found;
|
|
}
|
|
}
|
|
|
|
DPRINTF(("need to allocate the msqid_ds\n"));
|
|
if (key == IPC_PRIVATE || (msgflg & IPC_CREAT)) {
|
|
for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
|
|
/*
|
|
* Look for an unallocated and unlocked msqid_ds.
|
|
* msqid_ds's can be locked by msgsnd or msgrcv while
|
|
* they are copying the message in/out. We can't
|
|
* re-use the entry until they release it.
|
|
*/
|
|
msqptr = &msqids[msqid];
|
|
if (msqptr->msg_qbytes == 0 &&
|
|
(msqptr->msg_perm.mode & MSG_LOCKED) == 0)
|
|
break;
|
|
}
|
|
if (msqid == msginfo.msgmni) {
|
|
DPRINTF(("no more msqid_ds's available\n"));
|
|
error = ENOSPC;
|
|
goto done2;
|
|
}
|
|
DPRINTF(("msqid %d is available\n", msqid));
|
|
msqptr->msg_perm.key = key;
|
|
msqptr->msg_perm.cuid = cred->cr_uid;
|
|
msqptr->msg_perm.uid = cred->cr_uid;
|
|
msqptr->msg_perm.cgid = cred->cr_gid;
|
|
msqptr->msg_perm.gid = cred->cr_gid;
|
|
msqptr->msg_perm.mode = (msgflg & 0777);
|
|
/* Make sure that the returned msqid is unique */
|
|
msqptr->msg_perm.seq = (msqptr->msg_perm.seq + 1) & 0x7fff;
|
|
msqptr->msg_first = NULL;
|
|
msqptr->msg_last = NULL;
|
|
msqptr->msg_cbytes = 0;
|
|
msqptr->msg_qnum = 0;
|
|
msqptr->msg_qbytes = msginfo.msgmnb;
|
|
msqptr->msg_lspid = 0;
|
|
msqptr->msg_lrpid = 0;
|
|
msqptr->msg_stime = 0;
|
|
msqptr->msg_rtime = 0;
|
|
msqptr->msg_ctime = time_second;
|
|
} else {
|
|
DPRINTF(("didn't find it and wasn't asked to create it\n"));
|
|
error = ENOENT;
|
|
goto done2;
|
|
}
|
|
|
|
found:
|
|
/* Construct the unique msqid */
|
|
td->td_retval[0] = IXSEQ_TO_IPCID(msqid, msqptr->msg_perm);
|
|
done2:
|
|
mtx_unlock(&msq_mtx);
|
|
return (error);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct msgsnd_args {
|
|
int msqid;
|
|
void *msgp;
|
|
size_t msgsz;
|
|
int msgflg;
|
|
};
|
|
#endif
|
|
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
int
|
|
msgsnd(td, uap)
|
|
struct thread *td;
|
|
register struct msgsnd_args *uap;
|
|
{
|
|
int msqid = uap->msqid;
|
|
void *user_msgp = uap->msgp;
|
|
size_t msgsz = uap->msgsz;
|
|
int msgflg = uap->msgflg;
|
|
int segs_needed, error = 0;
|
|
register struct msqid_ds *msqptr;
|
|
register struct msg *msghdr;
|
|
short next;
|
|
|
|
DPRINTF(("call to msgsnd(%d, 0x%x, %d, %d)\n", msqid, user_msgp, msgsz,
|
|
msgflg));
|
|
if (!jail_sysvipc_allowed && jailed(td->td_ucred))
|
|
return (ENOSYS);
|
|
|
|
mtx_lock(&msq_mtx);
|
|
msqid = IPCID_TO_IX(msqid);
|
|
|
|
if (msqid < 0 || msqid >= msginfo.msgmni) {
|
|
DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqid,
|
|
msginfo.msgmni));
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
|
|
msqptr = &msqids[msqid];
|
|
if (msqptr->msg_qbytes == 0) {
|
|
DPRINTF(("no such message queue id\n"));
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
if (msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) {
|
|
DPRINTF(("wrong sequence number\n"));
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
|
|
if ((error = ipcperm(td, &msqptr->msg_perm, IPC_W))) {
|
|
DPRINTF(("requester doesn't have write access\n"));
|
|
goto done2;
|
|
}
|
|
|
|
segs_needed = (msgsz + msginfo.msgssz - 1) / msginfo.msgssz;
|
|
DPRINTF(("msgsz=%d, msgssz=%d, segs_needed=%d\n", msgsz, msginfo.msgssz,
|
|
segs_needed));
|
|
for (;;) {
|
|
int need_more_resources = 0;
|
|
|
|
/*
|
|
* check msgsz
|
|
* (inside this loop in case msg_qbytes changes while we sleep)
|
|
*/
|
|
|
|
if (msgsz > msqptr->msg_qbytes) {
|
|
DPRINTF(("msgsz > msqptr->msg_qbytes\n"));
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
|
|
if (msqptr->msg_perm.mode & MSG_LOCKED) {
|
|
DPRINTF(("msqid is locked\n"));
|
|
need_more_resources = 1;
|
|
}
|
|
if (msgsz + msqptr->msg_cbytes > msqptr->msg_qbytes) {
|
|
DPRINTF(("msgsz + msg_cbytes > msg_qbytes\n"));
|
|
need_more_resources = 1;
|
|
}
|
|
if (segs_needed > nfree_msgmaps) {
|
|
DPRINTF(("segs_needed > nfree_msgmaps\n"));
|
|
need_more_resources = 1;
|
|
}
|
|
if (free_msghdrs == NULL) {
|
|
DPRINTF(("no more msghdrs\n"));
|
|
need_more_resources = 1;
|
|
}
|
|
|
|
if (need_more_resources) {
|
|
int we_own_it;
|
|
|
|
if ((msgflg & IPC_NOWAIT) != 0) {
|
|
DPRINTF(("need more resources but caller "
|
|
"doesn't want to wait\n"));
|
|
error = EAGAIN;
|
|
goto done2;
|
|
}
|
|
|
|
if ((msqptr->msg_perm.mode & MSG_LOCKED) != 0) {
|
|
DPRINTF(("we don't own the msqid_ds\n"));
|
|
we_own_it = 0;
|
|
} else {
|
|
/* Force later arrivals to wait for our
|
|
request */
|
|
DPRINTF(("we own the msqid_ds\n"));
|
|
msqptr->msg_perm.mode |= MSG_LOCKED;
|
|
we_own_it = 1;
|
|
}
|
|
DPRINTF(("goodnight\n"));
|
|
error = msleep(msqptr, &msq_mtx, (PZERO - 4) | PCATCH,
|
|
"msgwait", 0);
|
|
DPRINTF(("good morning, error=%d\n", error));
|
|
if (we_own_it)
|
|
msqptr->msg_perm.mode &= ~MSG_LOCKED;
|
|
if (error != 0) {
|
|
DPRINTF(("msgsnd: interrupted system call\n"));
|
|
error = EINTR;
|
|
goto done2;
|
|
}
|
|
|
|
/*
|
|
* Make sure that the msq queue still exists
|
|
*/
|
|
|
|
if (msqptr->msg_qbytes == 0) {
|
|
DPRINTF(("msqid deleted\n"));
|
|
error = EIDRM;
|
|
goto done2;
|
|
}
|
|
|
|
} else {
|
|
DPRINTF(("got all the resources that we need\n"));
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* We have the resources that we need.
|
|
* Make sure!
|
|
*/
|
|
|
|
if (msqptr->msg_perm.mode & MSG_LOCKED)
|
|
panic("msg_perm.mode & MSG_LOCKED");
|
|
if (segs_needed > nfree_msgmaps)
|
|
panic("segs_needed > nfree_msgmaps");
|
|
if (msgsz + msqptr->msg_cbytes > msqptr->msg_qbytes)
|
|
panic("msgsz + msg_cbytes > msg_qbytes");
|
|
if (free_msghdrs == NULL)
|
|
panic("no more msghdrs");
|
|
|
|
/*
|
|
* Re-lock the msqid_ds in case we page-fault when copying in the
|
|
* message
|
|
*/
|
|
|
|
if ((msqptr->msg_perm.mode & MSG_LOCKED) != 0)
|
|
panic("msqid_ds is already locked");
|
|
msqptr->msg_perm.mode |= MSG_LOCKED;
|
|
|
|
/*
|
|
* Allocate a message header
|
|
*/
|
|
|
|
msghdr = free_msghdrs;
|
|
free_msghdrs = msghdr->msg_next;
|
|
msghdr->msg_spot = -1;
|
|
msghdr->msg_ts = msgsz;
|
|
|
|
/*
|
|
* Allocate space for the message
|
|
*/
|
|
|
|
while (segs_needed > 0) {
|
|
if (nfree_msgmaps <= 0)
|
|
panic("not enough msgmaps");
|
|
if (free_msgmaps == -1)
|
|
panic("nil free_msgmaps");
|
|
next = free_msgmaps;
|
|
if (next <= -1)
|
|
panic("next too low #1");
|
|
if (next >= msginfo.msgseg)
|
|
panic("next out of range #1");
|
|
DPRINTF(("allocating segment %d to message\n", next));
|
|
free_msgmaps = msgmaps[next].next;
|
|
nfree_msgmaps--;
|
|
msgmaps[next].next = msghdr->msg_spot;
|
|
msghdr->msg_spot = next;
|
|
segs_needed--;
|
|
}
|
|
|
|
/*
|
|
* Copy in the message type
|
|
*/
|
|
|
|
mtx_unlock(&msq_mtx);
|
|
if ((error = copyin(user_msgp, &msghdr->msg_type,
|
|
sizeof(msghdr->msg_type))) != 0) {
|
|
mtx_lock(&msq_mtx);
|
|
DPRINTF(("error %d copying the message type\n", error));
|
|
msg_freehdr(msghdr);
|
|
msqptr->msg_perm.mode &= ~MSG_LOCKED;
|
|
wakeup(msqptr);
|
|
goto done2;
|
|
}
|
|
mtx_lock(&msq_mtx);
|
|
user_msgp = (char *)user_msgp + sizeof(msghdr->msg_type);
|
|
|
|
/*
|
|
* Validate the message type
|
|
*/
|
|
|
|
if (msghdr->msg_type < 1) {
|
|
msg_freehdr(msghdr);
|
|
msqptr->msg_perm.mode &= ~MSG_LOCKED;
|
|
wakeup(msqptr);
|
|
DPRINTF(("mtype (%d) < 1\n", msghdr->msg_type));
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
|
|
/*
|
|
* Copy in the message body
|
|
*/
|
|
|
|
next = msghdr->msg_spot;
|
|
while (msgsz > 0) {
|
|
size_t tlen;
|
|
if (msgsz > msginfo.msgssz)
|
|
tlen = msginfo.msgssz;
|
|
else
|
|
tlen = msgsz;
|
|
if (next <= -1)
|
|
panic("next too low #2");
|
|
if (next >= msginfo.msgseg)
|
|
panic("next out of range #2");
|
|
mtx_unlock(&msq_mtx);
|
|
if ((error = copyin(user_msgp, &msgpool[next * msginfo.msgssz],
|
|
tlen)) != 0) {
|
|
mtx_lock(&msq_mtx);
|
|
DPRINTF(("error %d copying in message segment\n",
|
|
error));
|
|
msg_freehdr(msghdr);
|
|
msqptr->msg_perm.mode &= ~MSG_LOCKED;
|
|
wakeup(msqptr);
|
|
goto done2;
|
|
}
|
|
mtx_lock(&msq_mtx);
|
|
msgsz -= tlen;
|
|
user_msgp = (char *)user_msgp + tlen;
|
|
next = msgmaps[next].next;
|
|
}
|
|
if (next != -1)
|
|
panic("didn't use all the msg segments");
|
|
|
|
/*
|
|
* We've got the message. Unlock the msqid_ds.
|
|
*/
|
|
|
|
msqptr->msg_perm.mode &= ~MSG_LOCKED;
|
|
|
|
/*
|
|
* Make sure that the msqid_ds is still allocated.
|
|
*/
|
|
|
|
if (msqptr->msg_qbytes == 0) {
|
|
msg_freehdr(msghdr);
|
|
wakeup(msqptr);
|
|
error = EIDRM;
|
|
goto done2;
|
|
}
|
|
|
|
/*
|
|
* Put the message into the queue
|
|
*/
|
|
|
|
if (msqptr->msg_first == NULL) {
|
|
msqptr->msg_first = msghdr;
|
|
msqptr->msg_last = msghdr;
|
|
} else {
|
|
msqptr->msg_last->msg_next = msghdr;
|
|
msqptr->msg_last = msghdr;
|
|
}
|
|
msqptr->msg_last->msg_next = NULL;
|
|
|
|
msqptr->msg_cbytes += msghdr->msg_ts;
|
|
msqptr->msg_qnum++;
|
|
msqptr->msg_lspid = td->td_proc->p_pid;
|
|
msqptr->msg_stime = time_second;
|
|
|
|
wakeup(msqptr);
|
|
td->td_retval[0] = 0;
|
|
done2:
|
|
mtx_unlock(&msq_mtx);
|
|
return (error);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct msgrcv_args {
|
|
int msqid;
|
|
void *msgp;
|
|
size_t msgsz;
|
|
long msgtyp;
|
|
int msgflg;
|
|
};
|
|
#endif
|
|
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
int
|
|
msgrcv(td, uap)
|
|
struct thread *td;
|
|
register struct msgrcv_args *uap;
|
|
{
|
|
int msqid = uap->msqid;
|
|
void *user_msgp = uap->msgp;
|
|
size_t msgsz = uap->msgsz;
|
|
long msgtyp = uap->msgtyp;
|
|
int msgflg = uap->msgflg;
|
|
size_t len;
|
|
register struct msqid_ds *msqptr;
|
|
register struct msg *msghdr;
|
|
int error = 0;
|
|
short next;
|
|
|
|
DPRINTF(("call to msgrcv(%d, 0x%x, %d, %ld, %d)\n", msqid, user_msgp,
|
|
msgsz, msgtyp, msgflg));
|
|
|
|
if (!jail_sysvipc_allowed && jailed(td->td_ucred))
|
|
return (ENOSYS);
|
|
|
|
msqid = IPCID_TO_IX(msqid);
|
|
|
|
if (msqid < 0 || msqid >= msginfo.msgmni) {
|
|
DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqid,
|
|
msginfo.msgmni));
|
|
return (EINVAL);
|
|
}
|
|
|
|
msqptr = &msqids[msqid];
|
|
mtx_lock(&msq_mtx);
|
|
if (msqptr->msg_qbytes == 0) {
|
|
DPRINTF(("no such message queue id\n"));
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
if (msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) {
|
|
DPRINTF(("wrong sequence number\n"));
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
|
|
if ((error = ipcperm(td, &msqptr->msg_perm, IPC_R))) {
|
|
DPRINTF(("requester doesn't have read access\n"));
|
|
goto done2;
|
|
}
|
|
|
|
msghdr = NULL;
|
|
while (msghdr == NULL) {
|
|
if (msgtyp == 0) {
|
|
msghdr = msqptr->msg_first;
|
|
if (msghdr != NULL) {
|
|
if (msgsz < msghdr->msg_ts &&
|
|
(msgflg & MSG_NOERROR) == 0) {
|
|
DPRINTF(("first message on the queue "
|
|
"is too big (want %d, got %d)\n",
|
|
msgsz, msghdr->msg_ts));
|
|
error = E2BIG;
|
|
goto done2;
|
|
}
|
|
if (msqptr->msg_first == msqptr->msg_last) {
|
|
msqptr->msg_first = NULL;
|
|
msqptr->msg_last = NULL;
|
|
} else {
|
|
msqptr->msg_first = msghdr->msg_next;
|
|
if (msqptr->msg_first == NULL)
|
|
panic("msg_first/last screwed up #1");
|
|
}
|
|
}
|
|
} else {
|
|
struct msg *previous;
|
|
struct msg **prev;
|
|
|
|
previous = NULL;
|
|
prev = &(msqptr->msg_first);
|
|
while ((msghdr = *prev) != NULL) {
|
|
/*
|
|
* Is this message's type an exact match or is
|
|
* this message's type less than or equal to
|
|
* the absolute value of a negative msgtyp?
|
|
* Note that the second half of this test can
|
|
* NEVER be true if msgtyp is positive since
|
|
* msg_type is always positive!
|
|
*/
|
|
|
|
if (msgtyp == msghdr->msg_type ||
|
|
msghdr->msg_type <= -msgtyp) {
|
|
DPRINTF(("found message type %d, "
|
|
"requested %d\n",
|
|
msghdr->msg_type, msgtyp));
|
|
if (msgsz < msghdr->msg_ts &&
|
|
(msgflg & MSG_NOERROR) == 0) {
|
|
DPRINTF(("requested message "
|
|
"on the queue is too big "
|
|
"(want %d, got %d)\n",
|
|
msgsz, msghdr->msg_ts));
|
|
error = E2BIG;
|
|
goto done2;
|
|
}
|
|
*prev = msghdr->msg_next;
|
|
if (msghdr == msqptr->msg_last) {
|
|
if (previous == NULL) {
|
|
if (prev !=
|
|
&msqptr->msg_first)
|
|
panic("msg_first/last screwed up #2");
|
|
msqptr->msg_first =
|
|
NULL;
|
|
msqptr->msg_last =
|
|
NULL;
|
|
} else {
|
|
if (prev ==
|
|
&msqptr->msg_first)
|
|
panic("msg_first/last screwed up #3");
|
|
msqptr->msg_last =
|
|
previous;
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
previous = msghdr;
|
|
prev = &(msghdr->msg_next);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* We've either extracted the msghdr for the appropriate
|
|
* message or there isn't one.
|
|
* If there is one then bail out of this loop.
|
|
*/
|
|
|
|
if (msghdr != NULL)
|
|
break;
|
|
|
|
/*
|
|
* Hmph! No message found. Does the user want to wait?
|
|
*/
|
|
|
|
if ((msgflg & IPC_NOWAIT) != 0) {
|
|
DPRINTF(("no appropriate message found (msgtyp=%d)\n",
|
|
msgtyp));
|
|
/* The SVID says to return ENOMSG. */
|
|
error = ENOMSG;
|
|
goto done2;
|
|
}
|
|
|
|
/*
|
|
* Wait for something to happen
|
|
*/
|
|
|
|
DPRINTF(("msgrcv: goodnight\n"));
|
|
error = msleep(msqptr, &msq_mtx, (PZERO - 4) | PCATCH,
|
|
"msgwait", 0);
|
|
DPRINTF(("msgrcv: good morning (error=%d)\n", error));
|
|
|
|
if (error != 0) {
|
|
DPRINTF(("msgsnd: interrupted system call\n"));
|
|
error = EINTR;
|
|
goto done2;
|
|
}
|
|
|
|
/*
|
|
* Make sure that the msq queue still exists
|
|
*/
|
|
|
|
if (msqptr->msg_qbytes == 0 ||
|
|
msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) {
|
|
DPRINTF(("msqid deleted\n"));
|
|
error = EIDRM;
|
|
goto done2;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Return the message to the user.
|
|
*
|
|
* First, do the bookkeeping (before we risk being interrupted).
|
|
*/
|
|
|
|
msqptr->msg_cbytes -= msghdr->msg_ts;
|
|
msqptr->msg_qnum--;
|
|
msqptr->msg_lrpid = td->td_proc->p_pid;
|
|
msqptr->msg_rtime = time_second;
|
|
|
|
/*
|
|
* Make msgsz the actual amount that we'll be returning.
|
|
* Note that this effectively truncates the message if it is too long
|
|
* (since msgsz is never increased).
|
|
*/
|
|
|
|
DPRINTF(("found a message, msgsz=%d, msg_ts=%d\n", msgsz,
|
|
msghdr->msg_ts));
|
|
if (msgsz > msghdr->msg_ts)
|
|
msgsz = msghdr->msg_ts;
|
|
|
|
/*
|
|
* Return the type to the user.
|
|
*/
|
|
|
|
mtx_unlock(&msq_mtx);
|
|
error = copyout(&(msghdr->msg_type), user_msgp,
|
|
sizeof(msghdr->msg_type));
|
|
mtx_lock(&msq_mtx);
|
|
if (error != 0) {
|
|
DPRINTF(("error (%d) copying out message type\n", error));
|
|
msg_freehdr(msghdr);
|
|
wakeup(msqptr);
|
|
goto done2;
|
|
}
|
|
user_msgp = (char *)user_msgp + sizeof(msghdr->msg_type);
|
|
|
|
/*
|
|
* Return the segments to the user
|
|
*/
|
|
|
|
next = msghdr->msg_spot;
|
|
for (len = 0; len < msgsz; len += msginfo.msgssz) {
|
|
size_t tlen;
|
|
|
|
if (msgsz - len > msginfo.msgssz)
|
|
tlen = msginfo.msgssz;
|
|
else
|
|
tlen = msgsz - len;
|
|
if (next <= -1)
|
|
panic("next too low #3");
|
|
if (next >= msginfo.msgseg)
|
|
panic("next out of range #3");
|
|
mtx_unlock(&msq_mtx);
|
|
error = copyout(&msgpool[next * msginfo.msgssz],
|
|
user_msgp, tlen);
|
|
mtx_lock(&msq_mtx);
|
|
if (error != 0) {
|
|
DPRINTF(("error (%d) copying out message segment\n",
|
|
error));
|
|
msg_freehdr(msghdr);
|
|
wakeup(msqptr);
|
|
goto done2;
|
|
}
|
|
user_msgp = (char *)user_msgp + tlen;
|
|
next = msgmaps[next].next;
|
|
}
|
|
|
|
/*
|
|
* Done, return the actual number of bytes copied out.
|
|
*/
|
|
|
|
msg_freehdr(msghdr);
|
|
wakeup(msqptr);
|
|
td->td_retval[0] = msgsz;
|
|
done2:
|
|
mtx_unlock(&msq_mtx);
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
sysctl_msqids(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
|
|
return (SYSCTL_OUT(req, msqids,
|
|
sizeof(struct msqid_ds) * msginfo.msgmni));
|
|
}
|
|
|
|
SYSCTL_DECL(_kern_ipc);
|
|
SYSCTL_INT(_kern_ipc, OID_AUTO, msgmax, CTLFLAG_RD, &msginfo.msgmax, 0, "");
|
|
SYSCTL_INT(_kern_ipc, OID_AUTO, msgmni, CTLFLAG_RD, &msginfo.msgmni, 0, "");
|
|
SYSCTL_INT(_kern_ipc, OID_AUTO, msgmnb, CTLFLAG_RD, &msginfo.msgmnb, 0, "");
|
|
SYSCTL_INT(_kern_ipc, OID_AUTO, msgtql, CTLFLAG_RD, &msginfo.msgtql, 0, "");
|
|
SYSCTL_INT(_kern_ipc, OID_AUTO, msgssz, CTLFLAG_RD, &msginfo.msgssz, 0, "");
|
|
SYSCTL_INT(_kern_ipc, OID_AUTO, msgseg, CTLFLAG_RD, &msginfo.msgseg, 0, "");
|
|
SYSCTL_PROC(_kern_ipc, OID_AUTO, msqids, CTLFLAG_RD,
|
|
NULL, 0, sysctl_msqids, "", "Message queue IDs");
|