kern_syscalls.c revision 92547
1254721Semaste/*- 2254721Semaste * Copyright (c) 1999 Assar Westerlund 3254721Semaste * All rights reserved. 4254721Semaste * 5254721Semaste * Redistribution and use in source and binary forms, with or without 6254721Semaste * modification, are permitted provided that the following conditions 7254721Semaste * are met: 8254721Semaste * 1. Redistributions of source code must retain the above copyright 9254721Semaste * notice, this list of conditions and the following disclaimer. 10254721Semaste * 2. Redistributions in binary form must reproduce the above copyright 11254721Semaste * notice, this list of conditions and the following disclaimer in the 12254721Semaste * documentation and/or other materials provided with the distribution. 13254721Semaste * 14254721Semaste * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15254721Semaste * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16254721Semaste * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17254721Semaste * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18254721Semaste * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19254721Semaste * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20254721Semaste * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21254721Semaste * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22254721Semaste * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23254721Semaste * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24254721Semaste * SUCH DAMAGE. 25254721Semaste * 26254721Semaste * $FreeBSD: head/sys/kern/kern_syscalls.c 92547 2002-03-18 07:45:30Z arr $ 27254721Semaste */ 28254721Semaste 29254721Semaste#include <sys/param.h> 30254721Semaste#include <sys/sysproto.h> 31254721Semaste#include <sys/sysent.h> 32254721Semaste#include <sys/syscall.h> 33254721Semaste#include <sys/lock.h> 34254721Semaste#include <sys/mutex.h> 35254721Semaste#include <sys/sx.h> 36254721Semaste#include <sys/module.h> 37254721Semaste 38254721Semaste/* 39254721Semaste * Acts like "nosys" but can be identified in sysent for dynamic call 40254721Semaste * number assignment for a limited number of calls. 41254721Semaste * 42254721Semaste * Place holder for system call slots reserved for loadable modules. 43254721Semaste */ 44254721Semasteint 45254721Semastelkmnosys(struct thread *td, struct nosys_args *args) 46254721Semaste{ 47254721Semaste return(nosys(td, args)); 48254721Semaste} 49254721Semaste 50254721Semasteint 51254721Semastelkmressys(struct thread *td, struct nosys_args *args) 52254721Semaste{ 53254721Semaste return(nosys(td, args)); 54254721Semaste} 55254721Semaste 56254721Semasteint 57254721Semastesyscall_register(int *offset, struct sysent *new_sysent, 58254721Semaste struct sysent *old_sysent) 59254721Semaste{ 60254721Semaste if (*offset == NO_SYSCALL) { 61254721Semaste int i; 62254721Semaste 63254721Semaste for (i = 1; i < SYS_MAXSYSCALL; ++i) 64254721Semaste if (sysent[i].sy_call == (sy_call_t *)lkmnosys) 65254721Semaste break; 66254721Semaste if (i == SYS_MAXSYSCALL) 67254721Semaste return ENFILE; 68254721Semaste *offset = i; 69254721Semaste } else if (*offset < 0 || *offset >= SYS_MAXSYSCALL) 70254721Semaste return EINVAL; 71254721Semaste else if (sysent[*offset].sy_call != (sy_call_t *)lkmnosys && 72254721Semaste sysent[*offset].sy_call != (sy_call_t *)lkmressys) 73254721Semaste return EEXIST; 74254721Semaste 75254721Semaste *old_sysent = sysent[*offset]; 76254721Semaste sysent[*offset] = *new_sysent; 77254721Semaste return 0; 78254721Semaste} 79254721Semaste 80254721Semasteint 81254721Semastesyscall_deregister(int *offset, struct sysent *old_sysent) 82254721Semaste{ 83254721Semaste if (*offset) 84254721Semaste sysent[*offset] = *old_sysent; 85254721Semaste return 0; 86254721Semaste} 87254721Semaste 88254721Semasteint 89254721Semastesyscall_module_handler(struct module *mod, int what, void *arg) 90254721Semaste{ 91254721Semaste struct syscall_module_data *data = (struct syscall_module_data*)arg; 92254721Semaste modspecific_t ms; 93254721Semaste int error; 94254721Semaste 95254721Semaste switch (what) { 96254721Semaste case MOD_LOAD : 97254721Semaste error = syscall_register(data->offset, data->new_sysent, 98254721Semaste &data->old_sysent); 99254721Semaste if (error) 100254721Semaste return error; 101254721Semaste ms.intval = *data->offset; 102254721Semaste MOD_XLOCK; 103254721Semaste module_setspecific(mod, &ms); 104254721Semaste MOD_XUNLOCK; 105254721Semaste if (data->chainevh) 106254721Semaste error = data->chainevh(mod, what, data->chainarg); 107254721Semaste return error; 108254721Semaste 109254721Semaste case MOD_UNLOAD : 110254721Semaste if (data->chainevh) { 111254721Semaste error = data->chainevh(mod, what, data->chainarg); 112254721Semaste if (error) 113254721Semaste return error; 114254721Semaste } 115254721Semaste error = syscall_deregister(data->offset, &data->old_sysent); 116254721Semaste return error; 117254721Semaste } 118254721Semaste 119254721Semaste if (data->chainevh) 120254721Semaste return data->chainevh(mod, what, data->chainarg); 121254721Semaste else 122254721Semaste return 0; 123254721Semaste} 124254721Semaste