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Split out kernel side of msgctl(2) into two parts: the first that pops data

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from the userland and pushes results back and the second which does
actual processing. Use the latter to eliminate stackgap in the linux wrapper
of that syscall.

MFC after:      2 weeks
This commit is contained in:
Maxim Sobolev 2005-01-26 00:46:36 +00:00
parent 372ef8405c
commit f4b6eb045f
3 changed files with 50 additions and 38 deletions
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27
sys/compat/linux/linux_ipc.c
View File

@ -634,33 +634,26 @@ linux_msgget(struct thread *td, struct linux_msgget_args *args)
int
linux_msgctl(struct thread *td, struct linux_msgctl_args *args)
{
struct msgctl_args /* {
int msqid;
int cmd;
struct msqid_ds *buf;
} */ bsd_args;
int error;
int error, bsd_cmd;
struct l_msqid_ds linux_msqid;
caddr_t sg = stackgap_init();
struct msqid_ds bsd_msqid;
struct msqid_ds *bsd_msqptr;
error = linux_msqid_pullup(args->cmd & LINUX_IPC_64,
&linux_msqid, (caddr_t)PTRIN(args->buf));
if (error != 0)
return (error);
bsd_args.buf = (struct msqid_ds*)stackgap_alloc(&sg,
sizeof(struct l_msqid_ds));
bsd_args.msqid = args->msqid;
bsd_args.cmd = args->cmd & ~LINUX_IPC_64;
if (bsd_args.cmd == LINUX_IPC_SET)
linux_to_bsd_msqid_ds(&linux_msqid, bsd_args.buf);
bsd_cmd = args->cmd & ~LINUX_IPC_64;
if (bsd_cmd == LINUX_IPC_SET)
linux_to_bsd_msqid_ds(&linux_msqid, &bsd_msqid);
error = msgctl(td, &bsd_args);
error = kern_msgctl(td, args->msqid, bsd_cmd, &bsd_msqid, &bsd_msqptr);
if (error != 0)
if (bsd_args.cmd != LINUX_IPC_RMID || error != EINVAL)
if (bsd_cmd != LINUX_IPC_RMID || error != EINVAL)
return (error);
if (bsd_args.cmd == LINUX_IPC_STAT) {
bsd_to_linux_msqid_ds(bsd_args.buf, &linux_msqid);
if (bsd_cmd == LINUX_IPC_STAT) {
bsd_to_linux_msqid_ds(bsd_msqptr, &linux_msqid);
return (linux_msqid_pushdown(args->cmd & LINUX_IPC_64,
&linux_msqid, (caddr_t)PTRIN(args->buf)));
}

58
sys/kern/sysv_msg.c
View File

@ -64,6 +64,7 @@ __FBSDID("$FreeBSD$");
#include <sys/module.h>
#include <sys/msg.h>
#include <sys/syscall.h>
#include <sys/syscallsubr.h>
#include <sys/sysent.h>
#include <sys/sysctl.h>
#include <sys/malloc.h>
@ -395,27 +396,43 @@ msgctl(td, uap)
{
int msqid = uap->msqid;
int cmd = uap->cmd;
struct msqid_ds *user_msqptr = uap->buf;
int rval, error;
struct msqid_ds msqbuf;
struct msqid_ds *msqptr;
int error;
DPRINTF(("call to msgctl(%d, %d, 0x%x)\n", msqid, cmd, uap->buf));
if (cmd == IPC_SET &&
(error = copyin(uap->buf, &msqbuf, sizeof(msqbuf))) != 0)
return (error);
error = kern_msgctl(td, msqid, cmd, &msqbuf, &msqptr);
if (cmd == IPC_STAT && error == 0)
error = copyout(msqptr, uap->buf, sizeof(struct msqid_ds));
return (error);
}
int
kern_msgctl(td, msqid, cmd, msqbuf, msqptr)
struct thread *td;
int msqid;
int cmd;
struct msqid_ds *msqbuf;
struct msqid_ds **msqptr;
{
int rval, error, msqix;
register struct msqid_kernel *msqkptr;
DPRINTF(("call to msgctl(%d, %d, 0x%x)\n", msqid, cmd, user_msqptr));
if (!jail_sysvipc_allowed && jailed(td->td_ucred))
return (ENOSYS);
msqid = IPCID_TO_IX(msqid);
msqix = IPCID_TO_IX(msqid);
if (msqid < 0 || msqid >= msginfo.msgmni) {
DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqid,
if (msqix < 0 || msqix >= msginfo.msgmni) {
DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix,
msginfo.msgmni));
return (EINVAL);
}
if (cmd == IPC_SET &&
(error = copyin(user_msqptr, &msqbuf, sizeof(msqbuf))) != 0)
return (error);
msqkptr = &msqids[msqid];
msqkptr = &msqids[msqix];
mtx_lock(&msq_mtx);
if (msqkptr->u.msg_qbytes == 0) {
@ -423,7 +440,7 @@ msgctl(td, uap)
error = EINVAL;
goto done2;
}
if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) {
if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
DPRINTF(("wrong sequence number\n"));
error = EINVAL;
goto done2;
@ -500,26 +517,26 @@ msgctl(td, uap)
case IPC_SET:
if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_M)))
goto done2;
if (msqbuf.msg_qbytes > msqkptr->u.msg_qbytes) {
if (msqbuf->msg_qbytes > msqkptr->u.msg_qbytes) {
error = suser(td);
if (error)
goto done2;
}
if (msqbuf.msg_qbytes > msginfo.msgmnb) {
if (msqbuf->msg_qbytes > 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 */
msqbuf->msg_qbytes = msginfo.msgmnb; /* silently restrict qbytes to system limit */
}
if (msqbuf.msg_qbytes == 0) {
if (msqbuf->msg_qbytes == 0) {
DPRINTF(("can't reduce msg_qbytes to 0\n"));
error = EINVAL; /* non-standard errno! */
goto done2;
}
msqkptr->u.msg_perm.uid = msqbuf.msg_perm.uid; /* change the owner */
msqkptr->u.msg_perm.gid = msqbuf.msg_perm.gid; /* change the owner */
msqkptr->u.msg_perm.uid = msqbuf->msg_perm.uid; /* change the owner */
msqkptr->u.msg_perm.gid = msqbuf->msg_perm.gid; /* change the owner */
msqkptr->u.msg_perm.mode = (msqkptr->u.msg_perm.mode & ~0777) |
(msqbuf.msg_perm.mode & 0777);
msqkptr->u.msg_qbytes = msqbuf.msg_qbytes;
(msqbuf->msg_perm.mode & 0777);
msqkptr->u.msg_qbytes = msqbuf->msg_qbytes;
msqkptr->u.msg_ctime = time_second;
break;
@ -528,6 +545,7 @@ msgctl(td, uap)
DPRINTF(("requester doesn't have read access\n"));
goto done2;
}
*msqptr = &(msqkptr->u);
break;
default:
@ -540,8 +558,6 @@ msgctl(td, uap)
td->td_retval[0] = rval;
done2:
mtx_unlock(&msq_mtx);
if (cmd == IPC_STAT && error == 0)
error = copyout(&(msqkptr->u), user_msqptr, sizeof(struct msqid_ds));
return(error);
}

3
sys/sys/syscallsubr.h
View File

@ -39,6 +39,7 @@ struct rlimit;
struct rusage;
struct sockaddr;
struct itimerval;
struct msqid_ds;
int kern___getcwd(struct thread *td, u_char *buf, enum uio_seg bufseg,
u_int buflen);
@ -72,6 +73,8 @@ int kern_mkfifo(struct thread *td, char *path, enum uio_seg pathseg,
int mode);
int kern_mknod(struct thread *td, char *path, enum uio_seg pathseg,
int mode, int dev);
int kern_msgctl(struct thread *, int, int, struct msqid_ds *,
struct msqid_ds **);
int kern_nanosleep(struct thread *td, struct timespec *rqt,
struct timespec *rmt);
int kern_open(struct thread *td, char *path, enum uio_seg pathseg,