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Implement support for adding syscalls in KLD modules.
Submitted by: Assar Westerlund <assar@sics.se>
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svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=42433
sys
94
sys/kern/kern_syscalls.c
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94
sys/kern/kern_syscalls.c
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/*-
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* Copyright (c) 1999 Assar Westerlund
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: kern_syscalls.c,v 1.1 1999/01/03 06:00:55 root Exp root $
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*/
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/systm.h>
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#include <sys/malloc.h>
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#include <sys/sysproto.h>
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#include <sys/sysent.h>
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#include <sys/syscall.h>
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#include <sys/module.h>
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#include <sys/linker.h>
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#include <sys/proc.h>
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int
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syscall_register(int *offset, struct sysent *new_sysent,
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struct sysent *old_sysent)
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{
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if (*offset == NO_SYSCALL) {
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int i;
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for (i = 1; i < SYS_MAXSYSCALL; ++i)
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if (sysent[i].sy_call == (sy_call_t *)lkmnosys)
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break;
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if (i == SYS_MAXSYSCALL)
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return ENFILE;
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*offset = i;
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} else if (*offset < 0 || *offset >= SYS_MAXSYSCALL)
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return EINVAL;
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else if (sysent[*offset].sy_call != (sy_call_t *)lkmnosys)
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return EEXIST;
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*old_sysent = sysent[*offset];
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sysent[*offset] = *new_sysent;
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return 0;
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}
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int
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syscall_deregister(int *offset, struct sysent *old_sysent)
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{
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if (*offset)
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sysent[*offset] = *old_sysent;
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return 0;
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}
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int
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syscall_module_handler(struct module *mod, int what, void *arg)
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{
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struct syscall_module_data *data = (struct syscall_module_data*)arg;
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int error;
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switch (what) {
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case MOD_LOAD :
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error = syscall_register(data->offset, data->new_sysent,
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&data->old_sysent);
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if (error)
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return error;
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break;
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case MOD_UNLOAD :
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error = syscall_deregister(data->offset, &data->old_sysent);
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if (error)
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return error;
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break;
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}
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if (data->chainevh)
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return data->chainevh(mod, what, data->chainarg);
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else
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return 0;
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}
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@ -30,7 +30,7 @@
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: sysent.h,v 1.18 1998/06/07 17:13:03 dfr Exp $
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* $Id: sysent.h,v 1.19 1998/09/14 05:36:51 jdp Exp $
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*/
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#ifndef _SYS_SYSENT_H_
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@ -76,6 +76,36 @@ struct sysentvec {
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#ifdef KERNEL
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extern struct sysentvec aout_sysvec;
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extern struct sysent sysent[];
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#endif
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#define NO_SYSCALL (-1)
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struct module;
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struct syscall_module_data {
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int (*chainevh)(struct module *, int, void *); /* next handler */
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void *chainarg; /* arg for next event handler */
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int *offset; /* offset into sysent */
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struct sysent *new_sysent; /* new sysent */
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struct sysent old_sysent; /* old sysent */
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};
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#define SYSCALL_MODULE(name, offset, new_sysent, evh, arg) \
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static struct syscall_module_data name##_syscall_mod = { \
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evh, arg, offset, new_sysent \
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}; \
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\
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static moduledata_t name##_mod = { \
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#name, \
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syscall_module_handler, \
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&name##_syscall_mod \
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}; \
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DECLARE_MODULE(name, name##_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE)
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int syscall_register __P((int *offset, struct sysent *new_sysent,
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struct sysent *old_sysent));
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int syscall_deregister __P((int *offset, struct sysent *old_sysent));
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int syscall_module_handler __P((struct module *mod, int what, void *arg));
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#endif /* KERNEL */
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#endif /* !_SYS_SYSENT_H_ */
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