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725db531b8
prototypes for all syscalls. The args structs are still declared in comments as in VOP implementation functions. I don't like the duplication for this, but several more layers of changes are required to get it right. First we need to catch up with 4.4lite2, which uses macros to handle struct padding. Then we need to catch up with NetBSD, which passes the args correctly (as void *). Then we need to handle varargs functions and struct padding better. I think all the details can be hidden in machine-generated functions so that the args structs and verbose macros to reference them don't have to appear in the core sources. Add prototypes. Add bogus casts to hide the evil type puns exposed by the previous steps. &uap[1] was used to get at the args after the first. This worked because only the first arg in *uap was declared. This broke when the machine- genenerated args struct declared all the args (actually it declares extra args in some cases and depends on the user stack having some accessible junk after the last arg, not to mention the user args being on the stack. It isn't possible to declare a correct args struct for a varargs syscall). The msgsys(), semsys() and shmsys() syscall interfaces are BAD because they multiplex several syscalls that have different types of args. There was no reason to duplicate this sysv braindamage but now we're stuck with it. NetBSD has reimplemented the syscalls properly as separate syscalls #220-231. Declare static functions as static in both their prototype and their implementation (the latter is optional, and this misfeature was used). Remove gratuitous #includes. Continue cleaning up new init stuff.
1023 lines
23 KiB
C
1023 lines
23 KiB
C
/* $Id: sysv_msg.c,v 1.8 1995/09/09 18:10:06 davidg Exp $ */
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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 <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/msg.h>
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#include <sys/sysent.h>
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static void msginit __P((void *));
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SYSINIT(sysv_msg, SI_SUB_SYSV_MSG, SI_ORDER_FIRST, msginit, NULL)
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#define MSG_DEBUG
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#undef MSG_DEBUG_OK
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struct msgctl_args;
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static int msgctl __P((struct proc *p, struct msgctl_args *uap, int *retval));
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struct msgget_args;
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static int msgget __P((struct proc *p, struct msgget_args *uap, int *retval));
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struct msgsnd_args;
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static int msgsnd __P((struct proc *p, struct msgsnd_args *uap, int *retval));
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struct msgrcv_args;
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static int msgrcv __P((struct proc *p, struct msgrcv_args *uap, int *retval));
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static void msg_freehdr __P((struct msg *msghdr));
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/* XXX casting to (sy_call_t *) is bogus, as usual. */
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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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int nfree_msgmaps; /* # of free map entries */
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short free_msgmaps; /* head of linked list of free map entries */
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struct msg *free_msghdrs; /* list of free msg headers */
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char *msgpool; /* MSGMAX byte long msg buffer pool */
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struct msgmap *msgmaps; /* MSGSEG msgmap structures */
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struct msg *msghdrs; /* MSGTQL msg headers */
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struct msqid_ds *msqids; /* MSGMNI msqid_ds struct's */
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void
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msginit(dummy)
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void *dummy;
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{
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register int i;
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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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printf("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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printf("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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}
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}
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/*
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* Entry point for all MSG calls
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*/
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int
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msgsys(p, uap, retval)
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struct proc *p;
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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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int *retval;
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{
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if (uap->which >= sizeof(msgcalls)/sizeof(msgcalls[0]))
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return (EINVAL);
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return ((*msgcalls[uap->which])(p, &uap->a2, retval));
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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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struct msgctl_args {
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int msqid;
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int cmd;
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struct msqid_ds *user_msqptr;
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};
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static int
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msgctl(p, uap, retval)
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struct proc *p;
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register struct msgctl_args *uap;
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int *retval;
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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->user_msqptr;
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struct ucred *cred = p->p_ucred;
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int rval, eval;
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struct msqid_ds msqbuf;
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register struct msqid_ds *msqptr;
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#ifdef MSG_DEBUG_OK
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printf("call to msgctl(%d, %d, 0x%x)\n", msqid, cmd, user_msqptr);
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#endif
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msqid = IPCID_TO_IX(msqid);
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if (msqid < 0 || msqid >= msginfo.msgmni) {
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#ifdef MSG_DEBUG_OK
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printf("msqid (%d) out of range (0<=msqid<%d)\n", msqid,
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msginfo.msgmni);
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#endif
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return(EINVAL);
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}
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msqptr = &msqids[msqid];
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if (msqptr->msg_qbytes == 0) {
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#ifdef MSG_DEBUG_OK
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printf("no such msqid\n");
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#endif
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return(EINVAL);
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}
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if (msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) {
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#ifdef MSG_DEBUG_OK
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printf("wrong sequence number\n");
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#endif
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return(EINVAL);
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}
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eval = 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 ((eval = ipcperm(cred, &msqptr->msg_perm, IPC_M)))
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return(eval);
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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((caddr_t)msqptr);
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}
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break;
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case IPC_SET:
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if ((eval = ipcperm(cred, &msqptr->msg_perm, IPC_M)))
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return(eval);
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if ((eval = copyin(user_msqptr, &msqbuf, sizeof(msqbuf))) != 0)
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return(eval);
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if (msqbuf.msg_qbytes > msqptr->msg_qbytes && cred->cr_uid != 0)
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return(EPERM);
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if (msqbuf.msg_qbytes > msginfo.msgmnb) {
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#ifdef MSG_DEBUG_OK
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printf("can't increase msg_qbytes beyond %d (truncating)\n",
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msginfo.msgmnb);
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#endif
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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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#ifdef MSG_DEBUG_OK
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printf("can't reduce msg_qbytes to 0\n");
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#endif
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return(EINVAL); /* non-standard errno! */
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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.tv_sec;
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break;
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case IPC_STAT:
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if ((eval = ipcperm(cred, &msqptr->msg_perm, IPC_R))) {
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#ifdef MSG_DEBUG_OK
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printf("requester doesn't have read access\n");
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#endif
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return(eval);
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}
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eval = copyout((caddr_t)msqptr, user_msqptr,
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sizeof(struct msqid_ds));
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break;
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default:
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#ifdef MSG_DEBUG_OK
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printf("invalid command %d\n", cmd);
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#endif
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return(EINVAL);
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}
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if (eval == 0)
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*retval = rval;
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return(eval);
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}
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struct msgget_args {
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key_t key;
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int msgflg;
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};
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static int
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msgget(p, uap, retval)
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struct proc *p;
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register struct msgget_args *uap;
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int *retval;
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{
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int msqid, eval;
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int key = uap->key;
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int msgflg = uap->msgflg;
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struct ucred *cred = p->p_ucred;
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register struct msqid_ds *msqptr = NULL;
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#ifdef MSG_DEBUG_OK
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printf("msgget(0x%x, 0%o)\n", key, msgflg);
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#endif
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if (key != IPC_PRIVATE) {
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for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
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msqptr = &msqids[msqid];
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if (msqptr->msg_qbytes != 0 &&
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msqptr->msg_perm.key == key)
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break;
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}
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if (msqid < msginfo.msgmni) {
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#ifdef MSG_DEBUG_OK
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printf("found public key\n");
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#endif
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if ((msgflg & IPC_CREAT) && (msgflg & IPC_EXCL)) {
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#ifdef MSG_DEBUG_OK
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printf("not exclusive\n");
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#endif
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return(EEXIST);
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}
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if ((eval = ipcperm(cred, &msqptr->msg_perm, msgflg & 0700 ))) {
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#ifdef MSG_DEBUG_OK
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printf("requester doesn't have 0%o access\n",
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msgflg & 0700);
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#endif
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return(eval);
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}
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goto found;
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}
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}
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#ifdef MSG_DEBUG_OK
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printf("need to allocate the msqid_ds\n");
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#endif
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if (key == IPC_PRIVATE || (msgflg & IPC_CREAT)) {
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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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#ifdef MSG_DEBUG_OK
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printf("no more msqid_ds's available\n");
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#endif
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return(ENOSPC);
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}
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#ifdef MSG_DEBUG_OK
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printf("msqid %d is available\n", msqid);
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#endif
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msqptr->msg_perm.key = key;
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msqptr->msg_perm.cuid = cred->cr_uid;
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msqptr->msg_perm.uid = cred->cr_uid;
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msqptr->msg_perm.cgid = cred->cr_gid;
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msqptr->msg_perm.gid = cred->cr_gid;
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msqptr->msg_perm.mode = (msgflg & 0777);
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/* Make sure that the returned msqid is unique */
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msqptr->msg_perm.seq++;
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msqptr->msg_first = NULL;
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msqptr->msg_last = NULL;
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msqptr->msg_cbytes = 0;
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msqptr->msg_qnum = 0;
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msqptr->msg_qbytes = msginfo.msgmnb;
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msqptr->msg_lspid = 0;
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msqptr->msg_lrpid = 0;
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msqptr->msg_stime = 0;
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msqptr->msg_rtime = 0;
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msqptr->msg_ctime = time.tv_sec;
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} else {
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#ifdef MSG_DEBUG_OK
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printf("didn't find it and wasn't asked to create it\n");
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#endif
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return(ENOENT);
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}
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found:
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/* Construct the unique msqid */
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*retval = IXSEQ_TO_IPCID(msqid, msqptr->msg_perm);
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return(0);
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}
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struct msgsnd_args {
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int msqid;
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void *user_msgp;
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size_t msgsz;
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int msgflg;
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};
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static int
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msgsnd(p, uap, retval)
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struct proc *p;
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register struct msgsnd_args *uap;
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int *retval;
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{
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int msqid = uap->msqid;
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void *user_msgp = uap->user_msgp;
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size_t msgsz = uap->msgsz;
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int msgflg = uap->msgflg;
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int segs_needed, eval;
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struct ucred *cred = p->p_ucred;
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register struct msqid_ds *msqptr;
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register struct msg *msghdr;
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short next;
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#ifdef MSG_DEBUG_OK
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printf("call to msgsnd(%d, 0x%x, %d, %d)\n", msqid, user_msgp, msgsz,
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msgflg);
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#endif
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msqid = IPCID_TO_IX(msqid);
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if (msqid < 0 || msqid >= msginfo.msgmni) {
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#ifdef MSG_DEBUG_OK
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printf("msqid (%d) out of range (0<=msqid<%d)\n", msqid,
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msginfo.msgmni);
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#endif
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return(EINVAL);
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}
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msqptr = &msqids[msqid];
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if (msqptr->msg_qbytes == 0) {
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#ifdef MSG_DEBUG_OK
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printf("no such message queue id\n");
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#endif
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return(EINVAL);
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}
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if (msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) {
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#ifdef MSG_DEBUG_OK
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printf("wrong sequence number\n");
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#endif
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return(EINVAL);
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}
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|
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if ((eval = ipcperm(cred, &msqptr->msg_perm, IPC_W))) {
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#ifdef MSG_DEBUG_OK
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printf("requester doesn't have write access\n");
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#endif
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return(eval);
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}
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segs_needed = (msgsz + msginfo.msgssz - 1) / msginfo.msgssz;
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#ifdef MSG_DEBUG_OK
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printf("msgsz=%d, msgssz=%d, segs_needed=%d\n", msgsz, msginfo.msgssz,
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segs_needed);
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#endif
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for (;;) {
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int need_more_resources = 0;
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|
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/*
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* check msgsz
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* (inside this loop in case msg_qbytes changes while we sleep)
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*/
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if (msgsz > msqptr->msg_qbytes) {
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#ifdef MSG_DEBUG_OK
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printf("msgsz > msqptr->msg_qbytes\n");
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#endif
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return(EINVAL);
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}
|
|
|
|
if (msqptr->msg_perm.mode & MSG_LOCKED) {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("msqid is locked\n");
|
|
#endif
|
|
need_more_resources = 1;
|
|
}
|
|
if (msgsz + msqptr->msg_cbytes > msqptr->msg_qbytes) {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("msgsz + msg_cbytes > msg_qbytes\n");
|
|
#endif
|
|
need_more_resources = 1;
|
|
}
|
|
if (segs_needed > nfree_msgmaps) {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("segs_needed > nfree_msgmaps\n");
|
|
#endif
|
|
need_more_resources = 1;
|
|
}
|
|
if (free_msghdrs == NULL) {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("no more msghdrs\n");
|
|
#endif
|
|
need_more_resources = 1;
|
|
}
|
|
|
|
if (need_more_resources) {
|
|
int we_own_it;
|
|
|
|
if ((msgflg & IPC_NOWAIT) != 0) {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("need more resources but caller doesn't want to wait\n");
|
|
#endif
|
|
return(EAGAIN);
|
|
}
|
|
|
|
if ((msqptr->msg_perm.mode & MSG_LOCKED) != 0) {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("we don't own the msqid_ds\n");
|
|
#endif
|
|
we_own_it = 0;
|
|
} else {
|
|
/* Force later arrivals to wait for our
|
|
request */
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("we own the msqid_ds\n");
|
|
#endif
|
|
msqptr->msg_perm.mode |= MSG_LOCKED;
|
|
we_own_it = 1;
|
|
}
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("goodnight\n");
|
|
#endif
|
|
eval = tsleep((caddr_t)msqptr, (PZERO - 4) | PCATCH,
|
|
"msgwait", 0);
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("good morning, eval=%d\n", eval);
|
|
#endif
|
|
if (we_own_it)
|
|
msqptr->msg_perm.mode &= ~MSG_LOCKED;
|
|
if (eval != 0) {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("msgsnd: interrupted system call\n");
|
|
#endif
|
|
return(EINTR);
|
|
}
|
|
|
|
/*
|
|
* Make sure that the msq queue still exists
|
|
*/
|
|
|
|
if (msqptr->msg_qbytes == 0) {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("msqid deleted\n");
|
|
#endif
|
|
/* The SVID says to return EIDRM. */
|
|
#ifdef EIDRM
|
|
return(EIDRM);
|
|
#else
|
|
/* Unfortunately, BSD doesn't define that code
|
|
yet! */
|
|
return(EINVAL);
|
|
#endif
|
|
}
|
|
|
|
} else {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("got all the resources that we need\n");
|
|
#endif
|
|
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");
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("allocating segment %d to message\n", next);
|
|
#endif
|
|
free_msgmaps = msgmaps[next].next;
|
|
nfree_msgmaps--;
|
|
msgmaps[next].next = msghdr->msg_spot;
|
|
msghdr->msg_spot = next;
|
|
segs_needed--;
|
|
}
|
|
|
|
/*
|
|
* Copy in the message type
|
|
*/
|
|
|
|
if ((eval = copyin(user_msgp, &msghdr->msg_type,
|
|
sizeof(msghdr->msg_type))) != 0) {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("error %d copying the message type\n", eval);
|
|
#endif
|
|
msg_freehdr(msghdr);
|
|
msqptr->msg_perm.mode &= ~MSG_LOCKED;
|
|
wakeup((caddr_t)msqptr);
|
|
return(eval);
|
|
}
|
|
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((caddr_t)msqptr);
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("mtype (%d) < 1\n", msghdr->msg_type);
|
|
#endif
|
|
return(EINVAL);
|
|
}
|
|
|
|
/*
|
|
* 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");
|
|
if ((eval = copyin(user_msgp, &msgpool[next * msginfo.msgssz],
|
|
tlen)) != 0) {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("error %d copying in message segment\n", eval);
|
|
#endif
|
|
msg_freehdr(msghdr);
|
|
msqptr->msg_perm.mode &= ~MSG_LOCKED;
|
|
wakeup((caddr_t)msqptr);
|
|
return(eval);
|
|
}
|
|
msgsz -= tlen;
|
|
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((caddr_t)msqptr);
|
|
/* The SVID says to return EIDRM. */
|
|
#ifdef EIDRM
|
|
return(EIDRM);
|
|
#else
|
|
/* Unfortunately, BSD doesn't define that code yet! */
|
|
return(EINVAL);
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* 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 = p->p_pid;
|
|
msqptr->msg_stime = time.tv_sec;
|
|
|
|
wakeup((caddr_t)msqptr);
|
|
*retval = 0;
|
|
return(0);
|
|
}
|
|
|
|
struct msgrcv_args {
|
|
int msqid;
|
|
void *msgp;
|
|
size_t msgsz;
|
|
long msgtyp;
|
|
int msgflg;
|
|
};
|
|
|
|
static int
|
|
msgrcv(p, uap, retval)
|
|
struct proc *p;
|
|
register struct msgrcv_args *uap;
|
|
int *retval;
|
|
{
|
|
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;
|
|
struct ucred *cred = p->p_ucred;
|
|
register struct msqid_ds *msqptr;
|
|
register struct msg *msghdr;
|
|
int eval;
|
|
short next;
|
|
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("call to msgrcv(%d, 0x%x, %d, %ld, %d)\n", msqid, user_msgp,
|
|
msgsz, msgtyp, msgflg);
|
|
#endif
|
|
|
|
msqid = IPCID_TO_IX(msqid);
|
|
|
|
if (msqid < 0 || msqid >= msginfo.msgmni) {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("msqid (%d) out of range (0<=msqid<%d)\n", msqid,
|
|
msginfo.msgmni);
|
|
#endif
|
|
return(EINVAL);
|
|
}
|
|
|
|
msqptr = &msqids[msqid];
|
|
if (msqptr->msg_qbytes == 0) {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("no such message queue id\n");
|
|
#endif
|
|
return(EINVAL);
|
|
}
|
|
if (msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("wrong sequence number\n");
|
|
#endif
|
|
return(EINVAL);
|
|
}
|
|
|
|
if ((eval = ipcperm(cred, &msqptr->msg_perm, IPC_R))) {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("requester doesn't have read access\n");
|
|
#endif
|
|
return(eval);
|
|
}
|
|
|
|
msghdr = NULL;
|
|
while (msghdr == NULL) {
|
|
if (msgtyp == 0) {
|
|
msghdr = msqptr->msg_first;
|
|
if (msghdr != NULL) {
|
|
if (msgsz < msghdr->msg_ts &&
|
|
(msgflg & MSG_NOERROR) == 0) {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("first message on the queue is too big (want %d, got %d)\n",
|
|
msgsz, msghdr->msg_ts);
|
|
#endif
|
|
return(E2BIG);
|
|
}
|
|
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) {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("found message type %d, requested %d\n",
|
|
msghdr->msg_type, msgtyp);
|
|
#endif
|
|
if (msgsz < msghdr->msg_ts &&
|
|
(msgflg & MSG_NOERROR) == 0) {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("requested message on the queue is too big (want %d, got %d)\n",
|
|
msgsz, msghdr->msg_ts);
|
|
#endif
|
|
return(E2BIG);
|
|
}
|
|
*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) {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("no appropriate message found (msgtyp=%d)\n",
|
|
msgtyp);
|
|
#endif
|
|
/* The SVID says to return ENOMSG. */
|
|
#ifdef ENOMSG
|
|
return(ENOMSG);
|
|
#else
|
|
/* Unfortunately, BSD doesn't define that code yet! */
|
|
return(EAGAIN);
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Wait for something to happen
|
|
*/
|
|
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("msgrcv: goodnight\n");
|
|
#endif
|
|
eval = tsleep((caddr_t)msqptr, (PZERO - 4) | PCATCH, "msgwait",
|
|
0);
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("msgrcv: good morning (eval=%d)\n", eval);
|
|
#endif
|
|
|
|
if (eval != 0) {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("msgsnd: interrupted system call\n");
|
|
#endif
|
|
return(EINTR);
|
|
}
|
|
|
|
/*
|
|
* Make sure that the msq queue still exists
|
|
*/
|
|
|
|
if (msqptr->msg_qbytes == 0 ||
|
|
msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("msqid deleted\n");
|
|
#endif
|
|
/* The SVID says to return EIDRM. */
|
|
#ifdef EIDRM
|
|
return(EIDRM);
|
|
#else
|
|
/* Unfortunately, BSD doesn't define that code yet! */
|
|
return(EINVAL);
|
|
#endif
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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 = p->p_pid;
|
|
msqptr->msg_rtime = time.tv_sec;
|
|
|
|
/*
|
|
* 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).
|
|
*/
|
|
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("found a message, msgsz=%d, msg_ts=%d\n", msgsz,
|
|
msghdr->msg_ts);
|
|
#endif
|
|
if (msgsz > msghdr->msg_ts)
|
|
msgsz = msghdr->msg_ts;
|
|
|
|
/*
|
|
* Return the type to the user.
|
|
*/
|
|
|
|
eval = copyout((caddr_t)&(msghdr->msg_type), user_msgp,
|
|
sizeof(msghdr->msg_type));
|
|
if (eval != 0) {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("error (%d) copying out message type\n", eval);
|
|
#endif
|
|
msg_freehdr(msghdr);
|
|
wakeup((caddr_t)msqptr);
|
|
return(eval);
|
|
}
|
|
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 > msginfo.msgssz)
|
|
tlen = msginfo.msgssz;
|
|
else
|
|
tlen = msgsz;
|
|
if (next <= -1)
|
|
panic("next too low #3");
|
|
if (next >= msginfo.msgseg)
|
|
panic("next out of range #3");
|
|
eval = copyout((caddr_t)&msgpool[next * msginfo.msgssz],
|
|
user_msgp, tlen);
|
|
if (eval != 0) {
|
|
#ifdef MSG_DEBUG_OK
|
|
printf("error (%d) copying out message segment\n",
|
|
eval);
|
|
#endif
|
|
msg_freehdr(msghdr);
|
|
wakeup((caddr_t)msqptr);
|
|
return(eval);
|
|
}
|
|
user_msgp += tlen;
|
|
next = msgmaps[next].next;
|
|
}
|
|
|
|
/*
|
|
* Done, return the actual number of bytes copied out.
|
|
*/
|
|
|
|
msg_freehdr(msghdr);
|
|
wakeup((caddr_t)msqptr);
|
|
*retval = msgsz;
|
|
return(0);
|
|
}
|