[src/trunk]: src/sys/arch/usermode/modules/syscallemu Add 'syscallemu' module...

[jmcneill <jmcneill%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/92701df26d9d
branches:  trunk
changeset: 772476:92701df26d9d
user:      jmcneill <jmcneill%NetBSD.org@localhost>
date:      Thu Jan 05 13:26:51 2012 +0000

description:
Add 'syscallemu' module, required by usermode kernel.

This module registers a syscall that takes a user_start and user_end address.
When a process calls SYS_syscallemu, the start and end address are recorded
and the syscall installs a filter on p->p_md.md_syscall. The filter then
uses the specified start and end addresses to determine where the syscall
should be routed (either host by calling the original md_syscall function,
or process by posting SIGILL).

diffstat:

 sys/arch/usermode/modules/syscallemu/Makefile          |   16 +
 sys/arch/usermode/modules/syscallemu/syscallemu.c      |  187 +++++++++++++++++
 sys/arch/usermode/modules/syscallemu/syscallemu.h      |   77 +++++++
 sys/arch/usermode/modules/syscallemu/syscallemu_i386.c |  107 +++++++++
 4 files changed, 387 insertions(+), 0 deletions(-)

diffs (truncated from 403 to 300 lines):

diff -r 5daaa9e9c9dd -r 92701df26d9d sys/arch/usermode/modules/syscallemu/Makefile
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/sys/arch/usermode/modules/syscallemu/Makefile     Thu Jan 05 13:26:51 2012 +0000
@@ -0,0 +1,16 @@
+#      $NetBSD: Makefile,v 1.1 2012/01/05 13:26:51 jmcneill Exp $
+
+NETBSDSRCDIR?= ../../../../..
+
+S?=    ${NETBSDSRCDIR}/sys
+M?=    ${S}/modules
+
+.include "${M}/Makefile.inc"
+.include "${M}/Makefile.assym"
+
+KMOD=  syscallemu
+
+SRCS=  syscallemu.c
+SRCS+= syscallemu_${MACHINE_ARCH}.c
+
+.include <bsd.kmodule.mk>
diff -r 5daaa9e9c9dd -r 92701df26d9d sys/arch/usermode/modules/syscallemu/syscallemu.c
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/sys/arch/usermode/modules/syscallemu/syscallemu.c Thu Jan 05 13:26:51 2012 +0000
@@ -0,0 +1,187 @@
+/* $NetBSD: syscallemu.c,v 1.1 2012/01/05 13:26:51 jmcneill Exp $ */
+
+/*-
+ * Copyright (c) 2012 Jared D. McNeill <jmcneill%invisible.ca@localhost>
+ * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
+ */
+
+#include <sys/cdefs.h>
+__KERNEL_RCSID(0, "$NetBSD: syscallemu.c,v 1.1 2012/01/05 13:26:51 jmcneill Exp $");
+
+#include <sys/param.h>
+#include <sys/proc.h>
+#include <sys/systm.h>
+#include <sys/module.h>
+#include <sys/atomic.h>
+#include <sys/syscallvar.h>
+
+#include "syscallemu.h"
+
+#if !defined(__HAVE_SYSCALL_INTERN)
+#error syscallemu requires __HAVE_SYSCALL_INTERN
+#endif
+
+static specificdata_key_t syscallemu_data_key;
+static unsigned int syscallemu_refcnt;
+
+static const struct syscall_package syscallemu_syscalls[] = {
+       { SYS_syscallemu,       0, (sy_call_t *)sys_syscallemu  },
+       { 0, 0, NULL },
+};
+
+struct syscallemu_data *
+syscallemu_getsce(struct proc *p)
+{
+       return proc_getspecific(p, syscallemu_data_key);
+}
+
+void
+syscallemu_setsce(struct proc *p, struct syscallemu_data *sce)
+{
+       proc_setspecific(p, syscallemu_data_key, sce);
+}
+
+/*
+ * specificdata destructor
+ */
+static void
+syscallemu_dtor(void *priv)
+{
+       struct syscallemu_data *sce = priv;
+
+       kmem_free(sce, sizeof(*sce));
+       atomic_dec_uint(&syscallemu_refcnt);
+}
+
+/*
+ * Allocate private storage for the syscallemu parameters and stash it
+ * in process specificdata. This can only be called once per process.
+ *
+ * Returns EINVAL if the specified start address falls after the end.
+ * Returns EACCESS if syscallemu has already been configured for this process.
+ */
+int
+sys_syscallemu(lwp_t *l, const struct sys_syscallemu_args *uap,
+    register_t *retval)
+{
+       /* {
+               syscallarg(uintptr_t) user_start;
+               syscallarg(uintptr_t) user_end;
+       } */
+       vaddr_t user_start = (vaddr_t)SCARG(uap, user_start);
+       vaddr_t user_end = (vaddr_t)SCARG(uap, user_end);
+       struct syscallemu_data *sce;
+       struct proc *p = l->l_proc;
+
+       if (syscallemu_getsce(p) != NULL)
+               return EACCES;
+       if (user_start >= user_end)
+               return EINVAL;
+
+       sce = kmem_alloc(sizeof(*sce), KM_SLEEP);
+       sce->sce_user_start = user_start;
+       sce->sce_user_end = user_end;
+       sce->sce_md_syscall = md_syscallemu(p);
+       KASSERT(sce->sce_md_syscall != NULL);
+
+       atomic_inc_uint(&syscallemu_refcnt);
+       syscallemu_setsce(p, sce);
+
+#ifdef DEBUG
+       printf("syscallemu: enabled for pid %d\n", p->p_pid);
+#endif
+
+       return 0;
+}
+
+/*
+ * Initialize the syscallemu module
+ */
+static int
+syscallemu_init(void)
+{
+       int error;
+
+       syscallemu_refcnt = 0;
+
+       /* XXX workaround for kern/45781 */
+       if (emul_netbsd.e_sysent[SYS_syscallemu].sy_call == sys_nosys) {
+               printf("syscallemu: applying workaround for kern/45781\n");
+               emul_netbsd.e_sysent[SYS_syscallemu].sy_call = sys_nomodule;
+       }
+       emul_netbsd.e_sysent[SYS_syscallemu].sy_narg =
+           sizeof(struct sys_syscallemu_args) / sizeof(register_t);
+       emul_netbsd.e_sysent[SYS_syscallemu].sy_argsize =
+           sizeof(struct sys_syscallemu_args);
+
+       error = proc_specific_key_create(&syscallemu_data_key, syscallemu_dtor);
+       if (error) {
+               printf("syscallemu: couldn't create proc specific key (%d)\n",
+                   error);
+               return error;
+       }
+
+       error = syscall_establish(NULL, syscallemu_syscalls);
+       if (error) {
+               printf("syscallemu: couldn't establish syscalls\n");
+               proc_specific_key_delete(syscallemu_data_key);
+               return ENXIO;
+       }
+
+       return 0;
+}
+
+/*
+ * Finalize the syscallemu module
+ */
+static int
+syscallemu_fini(void)
+{
+       if (syscallemu_refcnt > 0)
+               return EBUSY;
+
+       syscall_disestablish(NULL, syscallemu_syscalls);
+       proc_specific_key_delete(syscallemu_data_key);
+       return 0;
+}
+
+/*
+ * Module glue
+ */
+MODULE(MODULE_CLASS_MISC, syscallemu, NULL);
+
+static int
+syscallemu_modcmd(modcmd_t cmd, void *arg)
+{
+       switch (cmd) {
+       case MODULE_CMD_INIT:
+               return syscallemu_init();       
+       case MODULE_CMD_FINI:
+               return syscallemu_fini();
+       case MODULE_CMD_AUTOUNLOAD:
+               return EBUSY;
+       default:
+               return ENOTTY;
+       }
+}
diff -r 5daaa9e9c9dd -r 92701df26d9d sys/arch/usermode/modules/syscallemu/syscallemu.h
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/sys/arch/usermode/modules/syscallemu/syscallemu.h Thu Jan 05 13:26:51 2012 +0000
@@ -0,0 +1,77 @@
+/* $NetBSD: syscallemu.h,v 1.1 2012/01/05 13:26:51 jmcneill Exp $ */
+
+/*-
+ * Copyright (c) 2012 Jared D. McNeill <jmcneill%invisible.ca@localhost>
+ * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
+ */
+
+#ifndef _HAVE_SYSCALLEMU_H
+#define _HAVE_SYSCALLEMU_H
+
+#include <sys/cdefs.h>
+#include <sys/syscall.h>
+#include <sys/syscallargs.h>
+
+struct proc;
+
+/*
+ * Process specific syscallemu configuration
+ */
+struct syscallemu_data { 
+       vaddr_t         sce_user_start;
+       vaddr_t         sce_user_end;
+       void            *sce_md_syscall;
+};
+
+/*
+ * Get process specific syscallemu data
+ */
+struct syscallemu_data *       syscallemu_getsce(struct proc *);
+
+/*
+ * Set process specific syscallemu data
+ */
+void   syscallemu_setsce(struct proc *, struct syscallemu_data *);
+
+/*
+ * MD specific syscallemu syscall setup (in syscallemu_${MACHINE_ARCH}.c)
+ */
+void * md_syscallemu(struct proc *);
+
+/* syscall: "syscallemu" ret: "int" args: "uintptr_t" "uintptr_t" */
+#define        SYS_syscallemu          511
+
+struct sys_syscallemu_args {
+       syscallarg(uintptr_t)   user_start;
+       syscallarg(uintptr_t)   user_end;
+};
+check_syscall_args(sys_syscallemu);
+
+int    sys_syscallemu(struct lwp *, const struct sys_syscallemu_args *,
+                      register_t *);
+
+__CTASSERT(SYS_syscallemu >= SYS_MAXSYSCALL);
+__CTASSERT(SYS_syscallemu < SYS_NSYSENT);
+
+#endif /* !_HAVE_SYSCALLEMU_H */
diff -r 5daaa9e9c9dd -r 92701df26d9d sys/arch/usermode/modules/syscallemu/syscallemu_i386.c
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/sys/arch/usermode/modules/syscallemu/syscallemu_i386.c    Thu Jan 05 13:26:51 2012 +0000
@@ -0,0 +1,107 @@
+/* $NetBSD: syscallemu_i386.c,v 1.1 2012/01/05 13:26:51 jmcneill Exp $ */
+
+/*-
+ * Copyright (c) 2011 Reinoud Zandijk <reinoud%NetBSD.org@localhost>