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 1.3 1999/01/17 18:58:04 peter Exp $ 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 /* 41 * Acts like "nosys" but can be identified in sysent for dynamic call 42 * number assignment for a limited number of calls. 43 * 44 * Place holder for system call slots reserved for loadable modules. 45 */ 46 int 47 lkmnosys(struct proc *p, struct nosys_args *args) 48 { 49 return(nosys(p, args)); 50 } 51 52 int 53 syscall_register(int *offset, struct sysent *new_sysent, 54 struct sysent *old_sysent) 55 { 56 if (*offset == NO_SYSCALL) { 57 int i; 58 59 for (i = 1; i < SYS_MAXSYSCALL; ++i) 60 if (sysent[i].sy_call == (sy_call_t *)lkmnosys) 61 break; 62 if (i == SYS_MAXSYSCALL) 63 return ENFILE; 64 *offset = i; 65 } else if (*offset < 0 || *offset >= SYS_MAXSYSCALL) 66 return EINVAL; 67 else if (sysent[*offset].sy_call != (sy_call_t *)lkmnosys) 68 return EEXIST; 69 70 *old_sysent = sysent[*offset]; 71 sysent[*offset] = *new_sysent; 72 return 0; 73 } 74 75 int 76 syscall_deregister(int *offset, struct sysent *old_sysent) 77 { 78 if (*offset) 79 sysent[*offset] = *old_sysent; 80 return 0; 81 } 82 83 int 84 syscall_module_handler(struct module *mod, int what, void *arg) 85 { 86 struct syscall_module_data *data = (struct syscall_module_data*)arg; 87 modspecific_t ms; 88 int error; 89 90 switch (what) { 91 case MOD_LOAD : 92 error = syscall_register(data->offset, data->new_sysent, 93 &data->old_sysent); 94 if (error) 95 return error; 96 ms.intval = *data->offset; 97 module_setspecific(mod, &ms); 98 if (data->chainevh) 99 error = data->chainevh(mod, what, data->chainarg); 100 return error; 101 102 case MOD_UNLOAD : 103 if (data->chainevh) { 104 error = data->chainevh(mod, what, data->chainarg); 105 if (error) 106 return error; 107 } 108 error = syscall_deregister(data->offset, &data->old_sysent); 109 return error; 110 } 111 112 if (data->chainevh) 113 return data->chainevh(mod, what, data->chainarg); 114 else 115 return 0; 116 } 117