1 /*- 2 * Copyright (c) 1999 Assar Westerlund 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $Id: kern_syscalls.c,v 1.1 1999/01/03 06:00:55 root Exp root $ 27 */ 28 29 #include <sys/param.h> 30 #include <sys/kernel.h> 31 #include <sys/systm.h> 32 #include <sys/malloc.h> 33 #include <sys/sysproto.h> 34 #include <sys/sysent.h> 35 #include <sys/syscall.h> 36 #include <sys/module.h> 37 #include <sys/linker.h> 38 #include <sys/proc.h> 39 40 int 41 syscall_register(int *offset, struct sysent *new_sysent, 42 struct sysent *old_sysent) 43 { 44 if (*offset == NO_SYSCALL) { 45 int i; 46 47 for (i = 1; i < SYS_MAXSYSCALL; ++i) 48 if (sysent[i].sy_call == (sy_call_t *)lkmnosys) 49 break; 50 if (i == SYS_MAXSYSCALL) 51 return ENFILE; 52 *offset = i; 53 } else if (*offset < 0 || *offset >= SYS_MAXSYSCALL) 54 return EINVAL; 55 else if (sysent[*offset].sy_call != (sy_call_t *)lkmnosys) 56 return EEXIST; 57 58 *old_sysent = sysent[*offset]; 59 sysent[*offset] = *new_sysent; 60 return 0; 61 } 62 63 int 64 syscall_deregister(int *offset, struct sysent *old_sysent) 65 { 66 if (*offset) 67 sysent[*offset] = *old_sysent; 68 return 0; 69 } 70 71 int 72 syscall_module_handler(struct module *mod, int what, void *arg) 73 { 74 struct syscall_module_data *data = (struct syscall_module_data*)arg; 75 int error; 76 77 switch (what) { 78 case MOD_LOAD : 79 error = syscall_register(data->offset, data->new_sysent, 80 &data->old_sysent); 81 if (error) 82 return error; 83 break; 84 case MOD_UNLOAD : 85 error = syscall_deregister(data->offset, &data->old_sysent); 86 if (error) 87 return error; 88 break; 89 } 90 if (data->chainevh) 91 return data->chainevh(mod, what, data->chainarg); 92 else 93 return 0; 94 } 95