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-rw-r--r--sys/kern/sysv_msg.c1038
1 files changed, 1038 insertions, 0 deletions
diff --git a/sys/kern/sysv_msg.c b/sys/kern/sysv_msg.c
new file mode 100644
index 000000000000..f861f53ece52
--- /dev/null
+++ b/sys/kern/sysv_msg.c
@@ -0,0 +1,1038 @@
+/*
+ * Implementation of SVID messages
+ *
+ * Author: Daniel Boulet
+ *
+ * Copyright 1993 Daniel Boulet and RTMX Inc.
+ *
+ * This system call was implemented by Daniel Boulet under contract from RTMX.
+ *
+ * Redistribution and use in source forms, with and without modification,
+ * are permitted provided that this entire comment appears intact.
+ *
+ * Redistribution in binary form may occur without any restrictions.
+ * Obviously, it would be nice if you gave credit where credit is due
+ * but requiring it would be too onerous.
+ *
+ * This software is provided ``AS IS'' without any warranties of any kind.
+ */
+
+#ifdef SYSVMSG
+
+#include "param.h"
+#include "systm.h"
+#include "kernel.h"
+#include "proc.h"
+#include "msg.h"
+#include "malloc.h"
+
+static int msgctl(), msgget(), msgsnd(), msgrcv();
+
+int (*msgcalls[])() = { msgctl, msgget, msgsnd, msgrcv };
+
+int nfree_msgmaps; /* # of free map entries */
+short free_msgmaps; /* head of linked list of free map entries */
+struct msg *free_msghdrs; /* list of free msg headers */
+
+void
+msginit()
+{
+ register int i;
+ vm_offset_t whocares1, whocares2;
+
+ /*
+ * msginfo.msgssz should be a power of two for efficiency reasons.
+ * It is also pretty silly if msginfo.msgssz is less than 8
+ * or greater than about 256 so ...
+ */
+
+ i = 8;
+ while ( i < 1024 && i != msginfo.msgssz ) {
+ i <<= 1;
+ }
+ if ( i != msginfo.msgssz ) {
+ printf("msginfo.msgssz=%d (0x%x)\n",msginfo.msgssz,msginfo.msgssz);
+ panic("msginfo.msgssz not a small power of 2");
+ }
+
+ if ( msginfo.msgseg > 32767 ) {
+ printf("msginfo.msgseg=%d\n",msginfo.msgseg);
+ panic("msginfo.msgseg > 32767");
+ }
+
+ if ( msgmaps == NULL ) {
+ panic("msgmaps is NULL");
+ }
+ for ( i = 0; i < msginfo.msgseg; i += 1 ) {
+ if ( i > 0 ) {
+ msgmaps[i-1].next = i;
+ }
+ msgmaps[i].next = -1; /* implies entry is available */
+ }
+ free_msgmaps = 0;
+ nfree_msgmaps = msginfo.msgseg;
+
+ if ( msghdrs == NULL ) {
+ panic("msghdrs is NULL");
+ }
+ for ( i = 0; i < msginfo.msgtql; i += 1 ) {
+ msghdrs[i].msg_type = 0;
+ if ( i > 0 ) {
+ msghdrs[i-1].msg_next = &msghdrs[i];
+ }
+ msghdrs[i].msg_next = NULL;
+ }
+ free_msghdrs = &msghdrs[0];
+
+ if ( msqids == NULL ) {
+ panic("msqids is NULL");
+ }
+ for ( i = 0; i < msginfo.msgmni; i += 1 ) {
+ msqids[i].msg_qbytes = 0; /* implies entry is available */
+ msqids[i].msg_perm.seq = 0; /* reset to a known value */
+ }
+
+}
+
+TEXT_SET(pseudo_set, msginit);
+
+/*
+ * Entry point for all MSG calls
+ */
+
+struct msgsys_args {
+ u_int which;
+};
+
+int
+msgsys(p, uap, retval)
+ struct caller *p;
+ struct msgsys_args *uap;
+ int *retval;
+{
+ if (uap->which >= sizeof(msgcalls)/sizeof(msgcalls[0]))
+ return (EINVAL);
+ return ((*msgcalls[uap->which])(p, &uap[1], retval));
+}
+
+static
+void
+msg_freehdr(msghdr)
+struct msg *msghdr;
+{
+ while ( msghdr->msg_ts > 0 ) {
+ short next;
+ if ( msghdr->msg_spot < 0 || msghdr->msg_spot >= msginfo.msgseg ) {
+ panic("msghdr->msg_spot out of range");
+ }
+ next = msgmaps[msghdr->msg_spot].next;
+ msgmaps[msghdr->msg_spot].next = free_msgmaps;
+ free_msgmaps = msghdr->msg_spot;
+ nfree_msgmaps += 1;
+ msghdr->msg_spot = next;
+ if ( msghdr->msg_ts >= msginfo.msgssz ) {
+ msghdr->msg_ts -= msginfo.msgssz;
+ } else {
+ msghdr->msg_ts = 0;
+ }
+ }
+ if ( msghdr->msg_spot != -1 ) {
+ panic("msghdr->msg_spot != -1");
+ }
+ msghdr->msg_next = free_msghdrs;
+ free_msghdrs = msghdr;
+}
+
+struct msgctl_args {
+ int msqid;
+ int cmd;
+ struct msqid_ds *user_msqptr;
+};
+
+int
+msgctl(p, uap, retval)
+ struct proc *p;
+ register struct msgctl_args *uap;
+ int *retval;
+{
+ int msqid = uap->msqid;
+ int cmd = uap->cmd;
+ struct msqid_ds *user_msqptr = uap->user_msqptr;
+ struct ucred *cred = p->p_ucred;
+ int i, rval, eval;
+ struct msqid_ds msqbuf;
+ register struct msqid_ds *msqptr;
+
+#ifdef MSG_DEBUG
+ printf("call to msgctl(%d,%d,0x%x)\n",msqid,cmd,user_msqptr);
+#endif
+
+ msqid = IPCID_TO_IX(msqid);
+
+ if ( msqid < 0 || msqid >= msginfo.msgmni ) {
+#ifdef MSG_DEBUG
+ 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
+ printf("no such msqid\n");
+#endif
+ return(EINVAL);
+ }
+ if ( msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid) ) {
+#ifdef MSG_DEBUG
+ printf("wrong sequence number\n");
+#endif
+ return(EINVAL);
+ }
+
+ eval = 0;
+ rval = 0;
+
+ switch (cmd) {
+
+ case IPC_RMID:
+#ifdef MSG_DEBUG
+ printf("IPC_RMID\n");
+#endif
+ {
+ struct msg *msghdr;
+
+ if ( cred->cr_uid != 0
+ && msqptr->msg_perm.cuid != cred->cr_uid
+ && msqptr->msg_perm.uid != cred->cr_uid ) {
+ return(EPERM);
+ }
+ msghdr = msqptr->msg_first;
+
+ /* Free the message headers */
+
+ while ( msghdr != NULL ) {
+ struct msg *msghdr_tmp;
+
+ /* Free the segments of each message */
+
+ msqptr->msg_cbytes -= msghdr->msg_ts;
+ msqptr->msg_qnum -= 1;
+ msghdr_tmp = msghdr;
+ msghdr = msghdr->msg_next;
+ msg_freehdr(msghdr_tmp);
+
+ }
+
+ if ( msqptr->msg_cbytes != 0 ) {
+ panic("msg_cbytes is screwed up");
+ }
+ if ( msqptr->msg_qnum != 0 ) {
+ panic("msg_qnum is screwed up");
+ }
+
+ msqptr->msg_qbytes = 0; /* Mark it as free */
+
+ /* Make sure that anybody who is waiting notices the deletion */
+
+ wakeup( (caddr_t)msqptr );
+ }
+
+ break;
+
+ case IPC_SET:
+#ifdef MSG_DEBUG
+ printf("IPC_SET\n");
+#endif
+ if ( cred->cr_uid != 0
+ && msqptr->msg_perm.cuid != cred->cr_uid
+ && msqptr->msg_perm.uid != cred->cr_uid ) {
+ return(EPERM);
+ }
+ if ( (eval = copyin(user_msqptr, &msqbuf, sizeof(msqbuf))) != 0 ) {
+ return(eval);
+ }
+ if ( msqbuf.msg_qbytes > msqptr->msg_qbytes
+ && cred->cr_uid != 0 ) {
+ return(EPERM);
+ }
+ if ( msqbuf.msg_qbytes > msginfo.msgmnb ) {
+#ifdef MSG_DEBUG
+ printf("can't increase msg_qbytes beyond %d (truncating)\n",msginfo.msgmnb);
+#endif
+ msqbuf.msg_qbytes = msginfo.msgmnb; /* silently restrict qbytes to system limit */
+ }
+ if ( msqbuf.msg_qbytes == 0 ) {
+#ifdef MSG_DEBUG
+ printf("can't reduce msg_qbytes to 0\n");
+#endif
+ return(EINVAL); /* non-standard errno! */
+ }
+ msqptr->msg_perm.uid = msqbuf.msg_perm.uid; /* change the owner */
+ msqptr->msg_perm.gid = msqbuf.msg_perm.gid; /* change the owner */
+ msqptr->msg_perm.mode = (msqptr->msg_perm.mode & ~0777)
+ | (msqbuf.msg_perm.mode & 0777);
+ msqptr->msg_qbytes = msqbuf.msg_qbytes;
+ msqptr->msg_ctime = time.tv_sec;
+ break;
+
+ case IPC_STAT:
+#ifdef MSG_DEBUG
+ printf("IPC_STAT\n");
+#endif
+ if ( (eval = ipcaccess(&msqptr->msg_perm, IPC_R, cred)) ) {
+#ifdef MSG_DEBUG
+ printf("requester doesn't have read access\n");
+#endif
+ return(eval);
+ }
+ rval = 0;
+ eval = copyout((caddr_t)msqptr, user_msqptr, sizeof(struct msqid_ds));
+ break;
+
+ default:
+#ifdef MSG_DEBUG
+ printf("invalid command %d\n",cmd);
+#endif
+ return(EINVAL);
+ }
+
+ if ( eval == 0 ) {
+ *retval = rval;
+ }
+ return(eval);
+}
+
+struct msgget_args {
+ key_t key;
+ int msgflg;
+};
+
+int
+msgget(p, uap, retval)
+ struct proc *p;
+ register struct msgget_args *uap;
+ int *retval;
+{
+ int msqid, eval;
+ int key = uap->key;
+ int msgflg = uap->msgflg;
+ struct ucred *cred = p->p_ucred;
+ register struct msqid_ds *msqptr = NULL;
+
+#ifdef MSG_DEBUG
+ printf("msgget(0x%x,0%o)\n",key,msgflg);
+#endif
+
+ if ( key == IPC_PRIVATE ) {
+#ifdef MSG_DEBUG
+ printf("private key\n");
+#endif
+ msqid = msginfo.msgmni;
+ } else {
+ for ( msqid = 0; msqid < msginfo.msgmni; msqid += 1 ) {
+ msqptr = &msqids[msqid];
+ if ( msqptr->msg_qbytes != 0 && msqptr->msg_perm.key == key ) {
+ break;
+ }
+ }
+ if ( msqid < msginfo.msgmni ) {
+#ifdef MSG_DEBUG
+ printf("found public key\n");
+#endif
+ if ( (msgflg & IPC_CREAT) && (msgflg & IPC_EXCL) ) {
+#ifdef MSG_DEBUG
+ printf("not exclusive\n");
+#endif
+ return(EEXIST);
+ }
+ if ( (eval = ipcaccess(&msqptr->msg_perm, msgflg & 0700, cred)) ) {
+#ifdef MSG_DEBUG
+ printf("requester doesn't have 0%o access\n",msgflg & 0700);
+#endif
+ return(eval);
+ }
+ } else {
+#ifdef MSG_DEBUG
+ printf("didn't find public key\n");
+#endif
+ }
+ }
+
+ if ( msqid == msginfo.msgmni ) {
+#ifdef MSG_DEBUG
+ printf("need to allocate the msqid_ds\n");
+#endif
+ if ( key == IPC_PRIVATE || (msgflg & IPC_CREAT) ) {
+ for ( msqid = 0; msqid < msginfo.msgmni; msqid += 1 ) {
+ /*
+ * 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 ) {
+#ifdef MSG_DEBUG
+ printf("no more msqid_ds's available\n");
+#endif
+ return(ENOSPC);
+ }
+#ifdef MSG_DEBUG
+ printf("msqid %d is available\n",msqid+1);
+#endif
+ 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);
+ msqptr->msg_perm.seq += 1; /* Make sure that the returned msqid is unique */
+ 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.tv_sec;
+ } else {
+#ifdef MSG_DEBUG
+ printf("didn't find it and wasn't asked to create it\n");
+#endif
+ return(ENOENT);
+ }
+ }
+
+ *retval = IXSEQ_TO_IPCID(msqid,msqptr->msg_perm); /* Construct the unique msqid */
+ return(0);
+}
+
+struct msgsnd_args {
+ int msqid;
+ void *user_msgp;
+ size_t msgsz;
+ int msgflg;
+};
+
+int
+msgsnd(p, uap, retval)
+ struct proc *p;
+ register struct msgsnd_args *uap;
+ int *retval;
+{
+ int msqid = uap->msqid;
+ void *user_msgp = uap->user_msgp;
+ size_t msgsz = uap->msgsz;
+ int msgflg = uap->msgflg;
+ int segs_needed, eval;
+ struct ucred *cred = p->p_ucred;
+ register struct msqid_ds *msqptr;
+ register struct msg *msghdr;
+ short next;
+
+#ifdef MSG_DEBUG
+ printf("call to msgsnd(%d,0x%x,%d,%d)\n",msqid,user_msgp,msgsz,msgflg);
+#endif
+
+ msqid = IPCID_TO_IX(msqid);
+
+ if ( msqid < 0 || msqid >= msginfo.msgmni ) {
+#ifdef MSG_DEBUG
+ 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
+ printf("no such message queue id\n");
+#endif
+ return(EINVAL);
+ }
+ if ( msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid) ) {
+#ifdef MSG_DEBUG
+ printf("wrong sequence number\n");
+#endif
+ return(EINVAL);
+ }
+
+ if ( (eval = ipcaccess(&msqptr->msg_perm, IPC_W, cred)) ) {
+#ifdef MSG_DEBUG
+ printf("requester doesn't have write access\n");
+#endif
+ return(eval);
+ }
+
+ segs_needed = (msgsz + msginfo.msgssz - 1) / msginfo.msgssz;
+#ifdef MSG_DEBUG
+ printf("msgsz=%d, msgssz=%d, segs_needed=%d\n",msgsz,msginfo.msgssz,segs_needed);
+#endif
+ while ( 1 ) {
+ int need_more_resources = 0;
+
+ /*
+ * check msgsz
+ * (inside this loop in case msg_qbytes changes while we sleep)
+ */
+
+ if ( msgsz > msqptr->msg_qbytes ) {
+#ifdef MSG_DEBUG
+ printf("msgsz > msqptr->msg_qbytes\n");
+#endif
+ return(EINVAL);
+ }
+
+ if ( msqptr->msg_perm.mode & MSG_LOCKED ) {
+#ifdef MSG_DEBUG
+ printf("msqid is locked\n");
+#endif
+ need_more_resources = 1;
+ }
+ if ( msgsz + msqptr->msg_cbytes > msqptr->msg_qbytes ) {
+#ifdef MSG_DEBUG
+ printf("msgsz + msg_cbytes > msg_qbytes\n");
+#endif
+ need_more_resources = 1;
+ }
+ if ( segs_needed > nfree_msgmaps ) {
+#ifdef MSG_DEBUG
+ printf("segs_needed > nfree_msgmaps\n");
+#endif
+ need_more_resources = 1;
+ }
+ if ( free_msghdrs == NULL ) {
+#ifdef MSG_DEBUG
+ 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
+ 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
+ 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
+ printf("we own the msqid_ds\n");
+#endif
+ msqptr->msg_perm.mode |= MSG_LOCKED;
+ we_own_it = 1;
+ }
+#ifdef MSG_DEBUG
+ printf("goodnight\n");
+#endif
+ eval = tsleep( (caddr_t)msqptr, (PZERO - 4) | PCATCH, "msg wait", 0 );
+#ifdef MSG_DEBUG
+ printf("good morning, eval=%d\n",eval);
+#endif
+ if ( we_own_it ) {
+ msqptr->msg_perm.mode &= ~MSG_LOCKED;
+ }
+ if ( eval != 0 ) {
+#ifdef MSG_DEBUG
+ 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
+ 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
+ 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"); /* bug somewhere */
+ }
+ if ( segs_needed > nfree_msgmaps ) {
+ panic("segs_needed > nfree_msgmaps"); /* bug somewhere */
+ }
+ if ( msgsz + msqptr->msg_cbytes > msqptr->msg_qbytes ) {
+ panic("msgsz + msg_cbytes > msg_qbytes"); /* bug somewhere */
+ }
+ if ( free_msghdrs == NULL ) {
+ panic("no more msghdrs"); /* bug somewhere */
+ }
+
+ /*
+ * 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
+ printf("allocating segment %d to message\n",next);
+#endif
+ free_msgmaps = msgmaps[next].next;
+ nfree_msgmaps -= 1;
+ msgmaps[next].next = msghdr->msg_spot;
+ msghdr->msg_spot = next;
+ segs_needed -= 1;
+ }
+
+ /*
+ * Copy in the message type
+ */
+
+ if ( (eval = copyin(user_msgp,&msghdr->msg_type,sizeof(msghdr->msg_type))) != 0 ) {
+#ifdef MSG_DEBUG
+ printf("error %d copying the message type\n",eval);
+#endif
+ msg_freehdr(msghdr);
+ msqptr->msg_perm.mode &= ~MSG_LOCKED;
+ wakeup( (caddr_t)msqptr ); /* Somebody might care - we should check! */
+ 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 ); /* Somebody might care - we should check! */
+#ifdef MSG_DEBUG
+ 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
+ printf("error %d copying in message segment\n",eval);
+#endif
+ msg_freehdr(msghdr);
+ msqptr->msg_perm.mode &= ~MSG_LOCKED;
+ wakeup( (caddr_t)msqptr ); /* Somebody might care - we should check! */
+ 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 ); /* Somebody might care - we should check! */
+ /* 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 += 1;
+ msqptr->msg_lspid = p->p_pid;
+ msqptr->msg_stime = time.tv_sec;
+
+ wakeup( (caddr_t)msqptr ); /* Somebody might care - we should check! */
+ *retval = 0;
+ return(0);
+}
+
+struct msgrcv_args {
+ int msqid;
+ void *msgp;
+ size_t msgsz;
+ long msgtyp;
+ int msgflg;
+};
+
+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
+ 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
+ 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
+ printf("no such message queue id\n");
+#endif
+ return(EINVAL);
+ }
+ if ( msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid) ) {
+#ifdef MSG_DEBUG
+ printf("wrong sequence number\n");
+#endif
+ return(EINVAL);
+ }
+
+ if ( (eval = ipcaccess(&msqptr->msg_perm, IPC_R, cred)) ) {
+#ifdef MSG_DEBUG
+ 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
+ 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
+ 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
+ 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
+ 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
+ printf("msgrcv: goodnight\n");
+#endif
+ eval = tsleep( (caddr_t)msqptr, (PZERO - 4) | PCATCH, "msg wait", 0 );
+#ifdef MSG_DEBUG
+ printf("msgrcv: good morning (eval=%d)\n",eval);
+#endif
+
+ if ( eval != 0 ) {
+#ifdef MSG_DEBUG
+ 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
+ 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 -= 1;
+ 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
+ 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
+ printf("error (%d) copying out message type\n",eval);
+#endif
+ msg_freehdr(msghdr);
+ wakeup( (caddr_t)msqptr ); /* Somebody might care - we should check! */
+ 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
+ printf("error (%d) copying out message segment\n",eval);
+#endif
+ msg_freehdr(msghdr);
+ wakeup( (caddr_t)msqptr ); /* Somebody might care - we should check! */
+ 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 ); /* Somebody might care - we should check! */
+ *retval = msgsz;
+ return(0);
+}
+#endif
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-25 15:41:29 +0000