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NetBSD/sys/kern/kern_syscall.c

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/* $NetBSD: kern_syscall.c,v 1.7 2012/05/05 19:37:37 christos Exp $ */
/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software developed for The NetBSD Foundation
* by Andrew Doran.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_syscall.c,v 1.7 2012/05/05 19:37:37 christos Exp $");
#include "opt_modular.h"
/* XXX To get syscall prototypes. */
#define SYSVSHM
#define SYSVSEM
#define SYSVMSG
#include <sys/param.h>
#include <sys/module.h>
#include <sys/sched.h>
#include <sys/syscall.h>
#include <sys/syscallargs.h>
#include <sys/syscallvar.h>
#include <sys/systm.h>
#include <sys/xcall.h>
int
sys_nomodule(struct lwp *l, const void *v, register_t *retval)
{
#ifdef MODULAR
static struct {
u_int al_code;
const char *al_module;
} const autoload[] = {
{ SYS_aio_cancel, "aio" },
{ SYS_aio_error, "aio" },
{ SYS_aio_fsync, "aio" },
{ SYS_aio_read, "aio" },
{ SYS_aio_return, "aio" },
{ SYS___aio_suspend50, "aio" },
{ SYS_aio_write, "aio" },
{ SYS_lio_listio, "aio" },
{ SYS_mq_open, "mqueue" },
{ SYS_mq_close, "mqueue" },
{ SYS_mq_unlink, "mqueue" },
{ SYS_mq_getattr, "mqueue" },
{ SYS_mq_setattr, "mqueue" },
{ SYS_mq_notify, "mqueue" },
{ SYS_mq_send, "mqueue" },
{ SYS_mq_receive, "mqueue" },
{ SYS___mq_timedsend50, "mqueue" },
{ SYS___mq_timedreceive50, "mqueue" },
{ SYS_compat_43_fstat43, "compat" },
{ SYS_compat_43_lstat43, "compat" },
{ SYS_compat_43_oaccept, "compat" },
{ SYS_compat_43_ocreat, "compat" },
{ SYS_compat_43_oftruncate, "compat" },
{ SYS_compat_43_ogetdirentries, "compat" },
{ SYS_compat_43_ogetdtablesize, "compat" },
{ SYS_compat_43_ogethostid, "compat" },
{ SYS_compat_43_ogethostname, "compat" },
{ SYS_compat_43_ogetkerninfo, "compat" },
{ SYS_compat_43_ogetpagesize, "compat" },
{ SYS_compat_43_ogetpeername, "compat" },
{ SYS_compat_43_ogetrlimit, "compat" },
{ SYS_compat_43_ogetsockname, "compat" },
{ SYS_compat_43_okillpg, "compat" },
{ SYS_compat_43_olseek, "compat" },
{ SYS_compat_43_ommap, "compat" },
{ SYS_compat_43_oquota, "compat" },
{ SYS_compat_43_orecv, "compat" },
{ SYS_compat_43_orecvfrom, "compat" },
{ SYS_compat_43_orecvmsg, "compat" },
{ SYS_compat_43_osend, "compat" },
{ SYS_compat_43_osendmsg, "compat" },
{ SYS_compat_43_osethostid, "compat" },
{ SYS_compat_43_osethostname, "compat" },
{ SYS_compat_43_osetrlimit, "compat" },
{ SYS_compat_43_osigblock, "compat" },
{ SYS_compat_43_osigsetmask, "compat" },
{ SYS_compat_43_osigstack, "compat" },
{ SYS_compat_43_osigvec, "compat" },
{ SYS_compat_43_otruncate, "compat" },
{ SYS_compat_43_owait, "compat" },
{ SYS_compat_43_stat43, "compat" },
{ SYS_compat_09_ogetdomainname, "compat" },
{ SYS_compat_09_osetdomainname, "compat" },
{ SYS_compat_09_ouname, "compat" },
#ifndef _LP64
{ SYS_compat_10_omsgsys, "compat" },
{ SYS_compat_10_osemsys, "compat" },
{ SYS_compat_10_oshmsys, "compat" },
#endif
{ SYS_compat_12_fstat12, "compat" },
{ SYS_compat_12_getdirentries, "compat" },
{ SYS_compat_12_lstat12, "compat" },
{ SYS_compat_12_msync, "compat" },
{ SYS_compat_12_oreboot, "compat" },
{ SYS_compat_12_oswapon, "compat" },
{ SYS_compat_12_stat12, "compat" },
{ SYS_compat_13_sigaction13, "compat" },
{ SYS_compat_13_sigaltstack13, "compat" },
{ SYS_compat_13_sigpending13, "compat" },
{ SYS_compat_13_sigprocmask13, "compat" },
{ SYS_compat_13_sigreturn13, "compat" },
{ SYS_compat_13_sigsuspend13, "compat" },
{ SYS_compat_14___semctl, "compat" },
{ SYS_compat_14_msgctl, "compat" },
{ SYS_compat_14_shmctl, "compat" },
{ SYS_compat_16___sigaction14, "compat" },
{ SYS_compat_16___sigreturn14, "compat" },
{ SYS_compat_20_fhstatfs, "compat" },
{ SYS_compat_20_fstatfs, "compat" },
{ SYS_compat_20_getfsstat, "compat" },
{ SYS_compat_20_statfs, "compat" },
{ SYS_compat_30___fhstat30, "compat" },
{ SYS_compat_30___fstat13, "compat" },
{ SYS_compat_30___lstat13, "compat" },
{ SYS_compat_30___stat13, "compat" },
{ SYS_compat_30_fhopen, "compat" },
{ SYS_compat_30_fhstat, "compat" },
{ SYS_compat_30_fhstatvfs1, "compat" },
{ SYS_compat_30_getdents, "compat" },
{ SYS_compat_30_getfh, "compat" },
{ SYS_compat_30_socket, "compat" },
{ SYS_compat_40_mount, "compat" },
{ SYS_compat_50_wait4, "compat" },
{ SYS_compat_50_mknod, "compat" },
{ SYS_compat_50_setitimer, "compat" },
{ SYS_compat_50_getitimer, "compat" },
{ SYS_compat_50_select, "compat" },
{ SYS_compat_50_gettimeofday, "compat" },
{ SYS_compat_50_getrusage, "compat" },
{ SYS_compat_50_settimeofday, "compat" },
{ SYS_compat_50_utimes, "compat" },
{ SYS_compat_50_adjtime, "compat" },
{ SYS_compat_50_lfs_segwait, "compat" },
{ SYS_compat_50_futimes, "compat" },
{ SYS_compat_50_clock_gettime, "compat" },
{ SYS_compat_50_clock_settime, "compat" },
{ SYS_compat_50_clock_getres, "compat" },
{ SYS_compat_50_timer_settime, "compat" },
{ SYS_compat_50_timer_gettime, "compat" },
{ SYS_compat_50_nanosleep, "compat" },
{ SYS_compat_50___sigtimedwait, "compat" },
{ SYS_compat_50_mq_timedsend, "compat" },
{ SYS_compat_50_mq_timedreceive, "compat" },
{ SYS_compat_50_lutimes, "compat" },
{ SYS_compat_50_____semctl13, "compat" },
{ SYS_compat_50___msgctl13, "compat" },
{ SYS_compat_50___shmctl13, "compat" },
{ SYS_compat_50__lwp_park, "compat" },
{ SYS_compat_50_kevent, "compat" },
{ SYS_compat_50_pselect, "compat" },
{ SYS_compat_50_pollts, "compat" },
{ SYS_compat_50___stat30, "compat" },
{ SYS_compat_50___fstat30, "compat" },
{ SYS_compat_50___lstat30, "compat" },
{ SYS_compat_50___ntp_gettime30, "compat" },
{ SYS_compat_50___fhstat40, "compat" },
{ SYS_compat_50_aio_suspend, "compat" },
{ SYS__ksem_init, "ksem" },
{ SYS__ksem_open, "ksem" },
{ SYS__ksem_unlink, "ksem" },
{ SYS__ksem_close, "ksem" },
{ SYS__ksem_post, "ksem" },
{ SYS__ksem_wait, "ksem" },
{ SYS__ksem_trywait, "ksem" },
{ SYS__ksem_getvalue, "ksem" },
{ SYS__ksem_destroy, "ksem" },
{ SYS__ksem_timedwait, "ksem" },
{ SYS_nfssvc, "nfsserver" },
{ SYS_afssys, "openafs" },
};
const struct sysent *sy;
const struct emul *em;
int code, i;
/*
* Restart the syscall if we interrupted a module unload that
* failed. Acquiring kernconfig_lock delays us until any unload
* has been completed or rolled back.
*/
kernconfig_lock();
sy = l->l_sysent;
if (sy->sy_call != sys_nomodule) {
kernconfig_unlock();
return ERESTART;
}
/*
* Try to autoload a module to satisfy the request. If it
* works, retry the request.
*/
em = l->l_proc->p_emul;
if (em == &emul_netbsd) {
code = sy - em->e_sysent;
for (i = 0; i < __arraycount(autoload); i++) {
if (autoload[i].al_code != code) {
continue;
}
if (module_autoload(autoload[i].al_module,
MODULE_CLASS_ANY) != 0 ||
sy->sy_call == sys_nomodule) {
break;
}
kernconfig_unlock();
return ERESTART;
}
}
kernconfig_unlock();
#endif /* MODULAR */
return sys_nosys(l, v, retval);
}
int
syscall_establish(const struct emul *em, const struct syscall_package *sp)
{
struct sysent *sy;
int i;
KASSERT(kernconfig_is_held());
if (em == NULL) {
em = &emul_netbsd;
}
sy = em->e_sysent;
/*
* Ensure that all preconditions are valid, since this is
* an all or nothing deal. Once a system call is entered,
* it can become busy and we could be unable to remove it
* on error.
*/
for (i = 0; sp[i].sp_call != NULL; i++) {
if (sy[sp[i].sp_code].sy_call != sys_nomodule) {
#ifdef DIAGNOSTIC
printf("syscall %d is busy\n", sp[i].sp_code);
#endif
return EBUSY;
}
}
/* Everything looks good, patch them in. */
for (i = 0; sp[i].sp_call != NULL; i++) {
sy[sp[i].sp_code].sy_call = sp[i].sp_call;
}
return 0;
}
int
syscall_disestablish(const struct emul *em, const struct syscall_package *sp)
{
struct sysent *sy;
uint64_t where;
lwp_t *l;
int i;
KASSERT(kernconfig_is_held());
if (em == NULL) {
em = &emul_netbsd;
}
sy = em->e_sysent;
/*
* First, patch the system calls to sys_nomodule to gate further
* activity.
*/
for (i = 0; sp[i].sp_call != NULL; i++) {
KASSERT(sy[sp[i].sp_code].sy_call == sp[i].sp_call);
sy[sp[i].sp_code].sy_call = sys_nomodule;
}
/*
* Run a cross call to cycle through all CPUs. This does two
* things: lock activity provides a barrier and makes our update
* of sy_call visible to all CPUs, and upon return we can be sure
* that we see pertinent values of l_sysent posted by remote CPUs.
*/
where = xc_broadcast(0, (xcfunc_t)nullop, NULL, NULL);
xc_wait(where);
/*
* Now it's safe to check l_sysent. Run through all LWPs and see
* if anyone is still using the system call.
*/
for (i = 0; sp[i].sp_call != NULL; i++) {
mutex_enter(proc_lock);
LIST_FOREACH(l, &alllwp, l_list) {
if (l->l_sysent == &sy[sp[i].sp_code]) {
break;
}
}
mutex_exit(proc_lock);
if (l == NULL) {
continue;
}
/*
* We lose: one or more calls are still in use. Put back
* the old entrypoints and act like nothing happened.
* When we drop kernconfig_lock, any system calls held in
* sys_nomodule() will be restarted.
*/
for (i = 0; sp[i].sp_call != NULL; i++) {
sy[sp[i].sp_code].sy_call = sp[i].sp_call;
}
return EBUSY;
}
return 0;
}
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