Date: Thu, 7 Jan 1999 13:10:01 -0800 (PST) From: Assar Westerlund <assar@sics.se> To: freebsd-bugs@FreeBSD.ORG Subject: Re: kern/9359: implement support for adding syscalls in KLD modules Message-ID: <199901072110.NAA17484@freefall.freebsd.org>
next in thread | raw e-mail | index | archive | help
The following reply was made to PR kern/9359; it has been noted by GNATS.
From: Assar Westerlund <assar@sics.se>
To: Doug Rabson <dfr@nlsystems.com>
Cc: FreeBSD-gnats-submit@freebsd.org
Subject: Re: kern/9359: implement support for adding syscalls in KLD modules
Date: 07 Jan 1999 22:08:09 +0100
Doug Rabson <dfr@nlsystems.com> writes:
> This looks good on first reading. Could you update the syscall kld
> example in share/examples/kld to use your new mechanism.
Sure, or rather, I added a new one in share/examples/kld/syscall and
removed the misc one. I also made a little modifications to my
previous patches to be able to retrieve the allocated syscall number.
I think some more general way of communicating the results of
dynamically allocating device major numbers and system calls number to
user-land is needed. I'm not sure how it should look like, but the
`-p' option to modload was at least a beginning.
/assar
----------------------------------------------------------------------
Index: share/examples/kld/Makefile
===================================================================
RCS file: /src/fbsd-repository/src/share/examples/kld/Makefile,v
retrieving revision 1.1
diff -u -w -r1.1 Makefile
--- Makefile 1998/12/11 10:44:30 1.1
+++ Makefile 1999/01/07 19:33:33
@@ -65,6 +65,6 @@
# SUCH DAMAGE.
#
-SUBDIR= cdev misc
+SUBDIR= cdev syscall
.include <bsd.subdir.mk>
--- /dev/null Thu Jan 7 21:47:47 1999
+++ share/examples/kld/syscall/Makefile Thu Jan 7 20:34:25 1999
@@ -0,0 +1,9 @@
+# Makefile for sample syscall module
+
+SUBDIR= module test
+
+load: _SUBDIRUSE
+
+unload: _SUBDIRUSE
+
+.include <bsd.subdir.mk>
--- /dev/null Thu Jan 7 21:47:47 1999
+++ share/examples/kld/syscall/module/Makefile Thu Jan 7 21:49:41 1999
@@ -0,0 +1,17 @@
+# Makefile for building the sample syscall module
+
+SRCS = syscall.c
+KMOD = syscall
+KO = ${KMOD}.ko
+KLDMOD = t
+
+KLDLOAD = /sbin/kldload
+KLDUNLOAD = /sbin/kldunload
+
+load: ${KO}
+ ${KLDLOAD} -v ./${KO}
+
+unload: ${KO}
+ ${KLDUNLOAD} -v -n ${KO}
+
+.include <bsd.kmod.mk>
--- /dev/null Thu Jan 7 21:47:47 1999
+++ share/examples/kld/syscall/module/syscall.c Thu Jan 7 21:51:07 1999
@@ -0,0 +1,86 @@
+/*-
+ * Copyright (c) 1999 Assar Westerlund
+ * All rights reserved.
+ *
+ * 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 AUTHOR 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 AUTHOR 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.
+ *
+ * $Id$
+ */
+
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/proc.h>
+#include <sys/module.h>
+#include <sys/sysent.h>
+#include <sys/kernel.h>
+#include <sys/systm.h>
+
+/*
+ * The function for implementing the syscall.
+ */
+
+static int
+hello (struct proc *p, void *arg)
+{
+ printf ("hello kernel\n");
+ return 0;
+}
+
+/*
+ * The `sysent' for the new syscall
+ */
+
+static struct sysent hello_sysent = {
+ 0, /* sy_narg */
+ hello /* sy_call */
+};
+
+/*
+ * The offset in sysent where the syscall is allocated.
+ */
+
+static int offset = NO_SYSCALL;
+
+/*
+ * The function called at load/unload.
+ */
+
+static int
+load (struct module *module, int cmd, void *arg)
+{
+ int error = 0;
+
+ switch (cmd) {
+ case MOD_LOAD :
+ printf ("syscall loaded at %d\n", offset);
+ break;
+ case MOD_UNLOAD :
+ printf ("syscall unloaded from %d\n", offset);
+ break;
+ default :
+ error = EINVAL;
+ break;
+ }
+ return error;
+}
+
+SYSCALL_MODULE(syscall, &offset, &hello_sysent, load, NULL);
--- /dev/null Thu Jan 7 21:47:47 1999
+++ share/examples/kld/syscall/test/call.c Thu Jan 7 21:58:01 1999
@@ -0,0 +1,53 @@
+/*-
+ * Copyright (c) 1999 Assar Westerlund
+ * All rights reserved.
+ *
+ * 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 AUTHOR 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 AUTHOR 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.
+ *
+ * $Id$
+ */
+
+#include <stdio.h>
+#include <sys/syscall.h>
+
+static void usage (void);
+
+static void
+usage (void)
+{
+ fprintf (stderr, "call syscall-number\n");
+ exit (1);
+}
+
+int
+main(int argc, char **argv)
+{
+ char *endptr;
+ int syscall_num;
+
+ if (argc != 2)
+ usage ();
+ syscall_num = strtol (argv[1], &endptr, 0);
+ if (syscall_num == 0 && argv[1] == endptr)
+ errx (1, "Bad number `%s'", argv[1]);
+ return syscall (syscall_num);
+}
--- /dev/null Thu Jan 7 21:47:47 1999
+++ share/examples/kld/syscall/test/Makefile Thu Jan 7 21:57:42 1999
@@ -0,0 +1,6 @@
+# Makefile for simple caller of syscall
+
+PROG = call
+NOMAN = noman
+
+.include <bsd.prog.mk>
Index: sys/sys/sysent.h
===================================================================
RCS file: /src/fbsd-repository/src/sys/sys/sysent.h,v
retrieving revision 1.19
diff -u -w -u -w -r1.19 sysent.h
--- sysent.h 1998/09/14 05:36:51 1.19
+++ sysent.h 1999/01/07 20:37:28
@@ -76,6 +76,36 @@
#ifdef KERNEL
extern struct sysentvec aout_sysvec;
extern struct sysent sysent[];
-#endif
+
+#define NO_SYSCALL (-1)
+
+struct module;
+
+struct syscall_module_data {
+ int (*chainevh)(struct module *, int, void *); /* next handler */
+ void *chainarg; /* arg for next event handler */
+ int *offset; /* offset into sysent */
+ struct sysent *new_sysent; /* new sysent */
+ struct sysent old_sysent; /* old sysent */
+};
+
+#define SYSCALL_MODULE(name, offset, new_sysent, evh, arg) \
+static struct syscall_module_data name##_syscall_mod = { \
+ evh, arg, offset, new_sysent \
+}; \
+ \
+static moduledata_t name##_mod = { \
+ #name, \
+ syscall_module_handler, \
+ &name##_syscall_mod \
+}; \
+DECLARE_MODULE(name, name##_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE)
+
+int syscall_register __P((int *offset, struct sysent *new_sysent,
+ struct sysent *old_sysent));
+int syscall_deregister __P((int *offset, struct sysent *old_sysent));
+int syscall_module_handler __P((struct module *mod, int what, void *arg));
+
+#endif /* KERNEL */
#endif /* !_SYS_SYSENT_H_ */
Index: sys/conf/files
===================================================================
RCS file: /src/fbsd-repository/src/sys/conf/files,v
retrieving revision 1.185
diff -u -w -u -w -r1.185 files
--- files 1998/12/28 16:31:26 1.185
+++ files 1999/01/07 19:39:39
@@ -289,6 +289,7 @@
kern/kern_sig.c standard
kern/kern_subr.c standard
kern/kern_synch.c standard
+kern/kern_syscalls.c standard
kern/kern_sysctl.c standard
kern/kern_time.c standard
kern/kern_timeout.c standard
--- /dev/null Thu Jan 7 21:47:47 1999
+++ sys/kern/kern_syscalls.c Thu Jan 7 21:37:53 1999
@@ -0,0 +1,94 @@
+/*-
+ * Copyright (c) 1999 Assar Westerlund
+ * All rights reserved.
+ *
+ * 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 AUTHOR 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 AUTHOR 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.
+ *
+ * $Id: kern_syscalls.c,v 1.1 1999/01/03 06:00:55 root Exp root $
+ */
+
+#include <sys/param.h>
+#include <sys/kernel.h>
+#include <sys/systm.h>
+#include <sys/malloc.h>
+#include <sys/sysproto.h>
+#include <sys/sysent.h>
+#include <sys/syscall.h>
+#include <sys/module.h>
+#include <sys/linker.h>
+#include <sys/proc.h>
+
+int
+syscall_register(int *offset, struct sysent *new_sysent,
+ struct sysent *old_sysent)
+{
+ if (*offset == NO_SYSCALL) {
+ int i;
+
+ for (i = 1; i < SYS_MAXSYSCALL; ++i)
+ if (sysent[i].sy_call == (sy_call_t *)lkmnosys)
+ break;
+ if (i == SYS_MAXSYSCALL)
+ return ENFILE;
+ *offset = i;
+ } else if (*offset < 0 || *offset >= SYS_MAXSYSCALL)
+ return EINVAL;
+ else if (sysent[*offset].sy_call != (sy_call_t *)lkmnosys)
+ return EEXIST;
+
+ *old_sysent = sysent[*offset];
+ sysent[*offset] = *new_sysent;
+ return 0;
+}
+
+int
+syscall_deregister(int *offset, struct sysent *old_sysent)
+{
+ if (*offset)
+ sysent[*offset] = *old_sysent;
+ return 0;
+}
+
+int
+syscall_module_handler(struct module *mod, int what, void *arg)
+{
+ struct syscall_module_data *data = (struct syscall_module_data*)arg;
+ int error;
+
+ switch (what) {
+ case MOD_LOAD :
+ error = syscall_register(data->offset, data->new_sysent,
+ &data->old_sysent);
+ if (error)
+ return error;
+ break;
+ case MOD_UNLOAD :
+ error = syscall_deregister(data->offset, &data->old_sysent);
+ if (error)
+ return error;
+ break;
+ }
+ if (data->chainevh)
+ return data->chainevh(mod, what, data->chainarg);
+ else
+ return 0;
+}
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-bugs" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199901072110.NAA17484>