diff options
Diffstat (limited to 'winsup/cygserver/sysv_msg.cc')
| -rw-r--r-- | winsup/cygserver/sysv_msg.cc | 1208 |
1 files changed, 1208 insertions, 0 deletions
diff --git a/winsup/cygserver/sysv_msg.cc b/winsup/cygserver/sysv_msg.cc new file mode 100644 index 000000000..9c1049c97 --- /dev/null +++ b/winsup/cygserver/sysv_msg.cc @@ -0,0 +1,1208 @@ +/* + * 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. + */ + +/* + * This file is heavily changed to become part of Cygwin's cygserver. + */ + +#ifdef __OUTSIDE_CYGWIN__ +#include "woutsup.h" +#include <sys/cdefs.h> +#ifndef __FBSDID +#define __FBSDID(s) const char version[] = (s) +#endif +__FBSDID("$FreeBSD: /usr/local/www/cvsroot/FreeBSD/src/sys/kern/sysv_msg.c,v 1.52 2003/11/07 04:47:14 rwatson Exp $"); + +#define _KERNEL 1 +#define __BSD_VISIBLE 1 +#include <sys/types.h> +#include <sys/sysproto.h> +#include <sys/ipc.h> +#include <sys/param.h> +#include <sys/msg.h> +#include <malloc.h> +#include <errno.h> +#include <time.h> +#include "cygserver.h" +#include "process.h" +#include "cygserver_ipc.h" + +#ifdef __CYGWIN__ +#define MSG_DEBUG +#endif /* __CYGWIN__ */ + +#ifdef MSG_DEBUG +#define DPRINTF(a) debug_printf a +#else +#define DPRINTF(a) +#endif + +static void msg_freehdr(struct msg *msghdr); + +#ifndef __CYGWIN__ +int msgctl(struct thread *, struct msgctl_args *); +int msgget(struct thread *, struct msgget_args *); +int msgsnd(struct thread *, struct msgsnd_args *); +int msgrcv(struct thread *, struct msgrcv_args *); + +static sy_call_t *msgcalls[] = { + (sy_call_t *)msgctl, (sy_call_t *)msgget, + (sy_call_t *)msgsnd, (sy_call_t *)msgrcv +}; +#endif /* __CYGWIN__ */ + + +struct msg { + struct msg *msg_next; /* next msg in the chain */ + long msg_type; /* type of this message */ + /* >0 -> type of this message */ + /* 0 -> free header */ + u_short msg_ts; /* size of this message */ + short msg_spot; /* location of start of msg in buffer */ +}; + + +#ifndef MSGSSZ +#define MSGSSZ 8 /* Each segment must be 2^N long */ +#endif +#ifndef MSGSEG +#define MSGSEG 2048 /* must be less than 32767 */ +#endif +#define MSGMAX (MSGSSZ*MSGSEG) +#ifndef MSGMNB +#define MSGMNB 2048 /* max # of bytes in a queue */ +#endif +#ifndef MSGMNI +#define MSGMNI 40 +#endif +#ifndef MSGTQL +#define MSGTQL 40 +#endif + +/* + * Based on the configuration parameters described in an SVR2 (yes, two) + * config(1m) man page. + * + * Each message is broken up and stored in segments that are msgssz bytes + * long. For efficiency reasons, this should be a power of two. Also, + * it doesn't make sense if it is less than 8 or greater than about 256. + * Consequently, msginit in kern/sysv_msg.c checks that msgssz is a power of + * two between 8 and 1024 inclusive (and panic's if it isn't). + */ +struct msginfo msginfo = { + MSGMAX, /* max chars in a message */ + MSGMNB, /* max chars in a queue */ + MSGMNI, /* # of message queue identifiers */ + MSGTQL, /* max messages in system */ + MSGSSZ, /* size of a message segment */ + /* (must be small power of 2 greater than 4) */ + MSGSEG /* number of message segments */ +}; + +/* + * macros to convert between msqid_ds's and msqid's. + * (specific to this implementation) + */ +#define MSQID(ix,ds) ((ix) & 0xffff | (((ds).msg_perm.seq << 16) & 0xffff0000)) +#define MSQID_IX(id) ((id) & 0xffff) +#define MSQID_SEQ(id) (((id) >> 16) & 0xffff) + +/* + * The rest of this file is specific to this particular implementation. + */ + +struct msgmap { + short next; /* next segment in buffer */ + /* -1 -> available */ + /* 0..(MSGSEG-1) -> index of next segment */ +}; + +#define MSG_LOCKED 01000 /* Is this msqid_ds locked? */ + +static int nfree_msgmaps; /* # of free map entries */ +static short free_msgmaps; /* head of linked list of free map entries */ +static struct msg *free_msghdrs;/* list of free msg headers */ +static char *msgpool; /* MSGMAX byte long msg buffer pool */ +static struct msgmap *msgmaps; /* MSGSEG msgmap structures */ +static struct msg *msghdrs; /* MSGTQL msg headers */ +static struct msqid_ds *msqids; /* MSGMNI msqid_ds struct's */ +static struct mtx msq_mtx; /* global mutex for message queues. */ + +#ifdef __CYGWIN__ +static struct msg_info msg_info; +#endif /* __CYGWIN__ */ + +void +msginit() +{ + int i; + + TUNABLE_INT_FETCH("kern.ipc.msgseg", &msginfo.msgseg); + TUNABLE_INT_FETCH("kern.ipc.msgssz", &msginfo.msgssz); + msginfo.msgmax = msginfo.msgseg * msginfo.msgssz; + TUNABLE_INT_FETCH("kern.ipc.msgmni", &msginfo.msgmni); + + msgpool = (char *) sys_malloc(msginfo.msgmax, M_MSG, M_WAITOK); + if (msgpool == NULL) + panic("msgpool is NULL"); + msgmaps = (msgmap *) sys_malloc(sizeof(struct msgmap) * msginfo.msgseg, M_MSG, M_WAITOK); + if (msgmaps == NULL) + panic("msgmaps is NULL"); + msghdrs = (msg *) sys_malloc(sizeof(struct msg) * msginfo.msgtql, M_MSG, M_WAITOK); + if (msghdrs == NULL) + panic("msghdrs is NULL"); + msqids = (msqid_ds *) sys_malloc(sizeof(struct msqid_ds) * msginfo.msgmni, M_MSG, M_WAITOK); + if (msqids == NULL) + panic("msqids is NULL"); + + /* + * 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) { + DPRINTF(("msginfo.msgssz=%d (0x%x)\n", msginfo.msgssz, + msginfo.msgssz)); + panic("msginfo.msgssz not a small power of 2"); + } + + if (msginfo.msgseg > 32767) { + DPRINTF(("msginfo.msgseg=%d\n", msginfo.msgseg)); + panic("msginfo.msgseg > 32767"); + } + + if (msgmaps == NULL) + panic("msgmaps is NULL"); + + for (i = 0; i < msginfo.msgseg; i++) { + 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++) { + 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++) { + msqids[i].msg_qbytes = 0; /* implies entry is available */ + msqids[i].msg_perm.seq = 0; /* reset to a known value */ + msqids[i].msg_perm.mode = 0; + } + mtx_init(&msq_mtx, "msq", NULL, MTX_DEF); +} + +int +msgunload() +{ + struct msqid_ds *msqptr; + int msqid; + + 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; + } +#ifndef __CYGWIN__ + if (msqid != msginfo.msgmni) + return (EBUSY); +#endif /* __CYGWIN__ */ + + sys_free(msgpool, M_MSG); + sys_free(msgmaps, M_MSG); + sys_free(msghdrs, M_MSG); + sys_free(msqids, M_MSG); + mtx_destroy(&msq_mtx); + return (0); +} + + +#ifndef __CYGWIN__ +static int +sysvmsg_modload(struct module *module, int cmd, void *arg) +{ + int error = 0; + + switch (cmd) { + case MOD_LOAD: + msginit(); + break; + case MOD_UNLOAD: + error = msgunload(); + break; + case MOD_SHUTDOWN: + break; + default: + error = EINVAL; + break; + } + return (error); +} + +static moduledata_t sysvmsg_mod = { + "sysvmsg", + &sysvmsg_modload, + NULL +}; + +SYSCALL_MODULE_HELPER(msgsys); +SYSCALL_MODULE_HELPER(msgctl); +SYSCALL_MODULE_HELPER(msgget); +SYSCALL_MODULE_HELPER(msgsnd); +SYSCALL_MODULE_HELPER(msgrcv); + +DECLARE_MODULE(sysvmsg, sysvmsg_mod, + SI_SUB_SYSV_MSG, SI_ORDER_FIRST); +MODULE_VERSION(sysvmsg, 1); + +/* + * Entry point for all MSG calls + * + * MPSAFE + */ +int +msgsys(thread *td, struct msgsys_args *uap) +{ + int error; + + if (!jail_sysvipc_allowed && jailed(td->td_ucred)) + return (ENOSYS); + if (uap->which < 0 || + (unsigned) uap->which >= sizeof(msgcalls)/sizeof(msgcalls[0])) + return (EINVAL); + error = (*msgcalls[uap->which])(td, &uap->a2); + return (error); +} +#endif + +static void +msg_freehdr(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++; + 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; +} + +#ifndef _SYS_SYSPROTO_H_ +struct msgctl_args { + int msqid; + int cmd; + struct msqid_ds *buf; +}; +#endif + +/* + * MPSAFE + */ +int +msgctl(struct thread *td, struct msgctl_args *uap) +{ + int msqid = uap->msqid; + int cmd = uap->cmd; + struct msqid_ds *user_msqptr = uap->buf; + int rval, error; + struct msqid_ds msqbuf; + register struct msqid_ds *msqptr; + + DPRINTF(("call to msgctl(%d, %d, 0x%x)\n", msqid, cmd, user_msqptr)); + + if (!jail_sysvipc_allowed && jailed(td->td_ucred)) + return (ENOSYS); + +#ifdef __CYGWIN__ + if (cmd == IPC_INFO) { + if (!msqid) { + error = copyout(&msginfo, user_msqptr, + sizeof(struct msginfo)); + td->td_retval[0] = error ? -1 : 0; + return (error); + } + if (msqid > msginfo.msgmni) + msqid = msginfo.msgmni; + error = copyout(msqids, user_msqptr, + msqid * sizeof(struct msqid_ds)); + td->td_retval[0] = error ? -1 : 0; + return (error); + } else if (cmd == MSG_INFO) { + mtx_lock(&msq_mtx); + error = copyout(&msg_info, user_msqptr, + sizeof(struct msg_info)); + td->td_retval[0] = error ? -1 : 0; + mtx_unlock(&msq_mtx); + return (error); + } +#endif /* __CYGWIN__ */ + 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); + } + if (cmd == IPC_SET && + (error = copyin(user_msqptr, &msqbuf, sizeof(msqbuf))) != 0) + return (error); + + msqptr = &msqids[msqid]; + + mtx_lock(&msq_mtx); + if (msqptr->msg_qbytes == 0) { + DPRINTF(("no such msqid\n")); + error = EINVAL; + goto done2; + } + if (msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) { + DPRINTF(("wrong sequence number\n")); + error = EINVAL; + goto done2; + } + + error = 0; + rval = 0; + + switch (cmd) { + + case IPC_RMID: + { + struct msg *msghdr; + if ((error = ipcperm(td, &msqptr->msg_perm, IPC_M))) + goto done2; + /* Free the message headers */ + msghdr = msqptr->msg_first; + while (msghdr != NULL) { + struct msg *msghdr_tmp; + + /* Free the segments of each message */ + msqptr->msg_cbytes -= msghdr->msg_ts; + msqptr->msg_qnum--; + 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 */ +#ifdef __CYGWIN__ + msg_info.msg_ids--; +#endif /* __CYGWIN__ */ + + wakeup(msqptr); + } + + break; + + case IPC_SET: + if ((error = ipcperm(td, &msqptr->msg_perm, IPC_M))) + goto done2; + if (msqbuf.msg_qbytes > msqptr->msg_qbytes) { + error = suser(td); + if (error) + goto done2; + } + if (msqbuf.msg_qbytes > (unsigned long) msginfo.msgmnb) { + DPRINTF(("can't increase msg_qbytes beyond %d" + "(truncating)\n", msginfo.msgmnb)); + msqbuf.msg_qbytes = msginfo.msgmnb; /* silently restrict qbytes to system limit */ + } + if (msqbuf.msg_qbytes == 0) { + DPRINTF(("can't reduce msg_qbytes to 0\n")); + error = EINVAL; /* non-standard errno! */ + goto done2; + } + 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 (NULL); + break; + + case IPC_STAT: + if ((error = ipcperm(td, &msqptr->msg_perm, IPC_R))) { + DPRINTF(("requester doesn't have read access\n")); + goto done2; + } + break; + + default: + DPRINTF(("invalid command %d\n", cmd)); + error = EINVAL; + goto done2; + } + + if (error == 0) + td->td_retval[0] = rval; +done2: + mtx_unlock(&msq_mtx); + if (cmd == IPC_STAT && error == 0) + error = copyout(msqptr, user_msqptr, sizeof(struct msqid_ds)); + return(error); +} + +#ifndef _SYS_SYSPROTO_H_ +struct msgget_args { + key_t key; + int msgflg; +}; +#endif + +/* + * MPSAFE + */ +int +msgget(struct thread *td, struct msgget_args *uap) +{ + int msqid, error = 0; + key_t key = uap->key; + unsigned msgflg = uap->msgflg; + register struct msqid_ds *msqptr = NULL; + + DPRINTF(("msgget(0x%x, 0%o)\n", key, msgflg)); + + if (!jail_sysvipc_allowed && jailed(td->td_ucred)) + return (ENOSYS); + + mtx_lock(&msq_mtx); + if (key != IPC_PRIVATE) { + for (msqid = 0; msqid < msginfo.msgmni; msqid++) { + msqptr = &msqids[msqid]; + if (msqptr->msg_qbytes != 0 && + msqptr->msg_perm.key == key) + break; + } + if (msqid < msginfo.msgmni) { + 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; +#ifdef __CYGWIN__ + msqptr->msg_perm.cuid = td->ipcblk->uid; + msqptr->msg_perm.uid = td->ipcblk->uid; + msqptr->msg_perm.cgid = td->ipcblk->gid; + msqptr->msg_perm.gid = td->ipcblk->gid; +#else + 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; +#endif /* __CYGWIN__ */ + 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 (NULL); +#ifdef __CYGWIN__ + msg_info.msg_ids++; +#endif /* __CYGWIN__ */ + } 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; + const void *msgp; + size_t msgsz; + int msgflg; +}; +#endif + +/* + * MPSAFE + */ +int +msgsnd(struct thread *td, struct msgsnd_args *uap) +{ + int msqid = uap->msqid; + const 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")); +#ifdef __CYGWIN__ + if (error != EIDRM) +#endif /* __CYGWIN__ */ + 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 = (const 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 > (unsigned long) 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 = (const 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 (NULL); + +#ifdef __CYGWIN__ + msg_info.msg_num++; + msg_info.msg_tot += uap->msgsz; +#endif /* __CYGWIN__ */ + + 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(struct thread *td, 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")); +#ifdef __CYGWIN__ + if (error != EIDRM) +#endif /* __CYGWIN__ */ + 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 (NULL); + + /* + * 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 > (unsigned long) 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. + */ + +#ifdef __CYGWIN__ + msg_info.msg_num--; + msg_info.msg_tot -= msgsz; +#endif /* __CYGWIN__ */ + + msg_freehdr(msghdr); + wakeup(msqptr); + td->td_retval[0] = msgsz; +done2: + mtx_unlock(&msq_mtx); + return (error); +} + +#ifndef __CYGWIN__ +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_RDTUN, &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_RDTUN, &msginfo.msgssz, 0, ""); +SYSCTL_INT(_kern_ipc, OID_AUTO, msgseg, CTLFLAG_RDTUN, &msginfo.msgseg, 0, ""); +SYSCTL_PROC(_kern_ipc, OID_AUTO, msqids, CTLFLAG_RD, + NULL, 0, sysctl_msqids, "", "Message queue IDs"); +#endif /* __CYGWIN__ */ +#endif /* __OUTSIDE_CYGWIN__ */ |