a.out emulation for dynamic binaries: intercept the right system calls

so that they look in /emul/a.out first. This allows a.out's ld.so to
find its own libraries without interfering with ELF at all.

Many comments from various people. okay deraadt@

3 files changed, 204 insertions, 3 deletions

diff --git a/sys/compat/aout/compat_aout.c b/sys/compat/aout/compat_aout.c
new file mode 100644
index 00000000000..075524cde75
--- /dev/null
+++ b/sys/compat/aout/compat_aout.c
@@ -0,0 +1,195 @@
+/* 	$OpenBSD: compat_aout.c,v 1.1 2003/06/24 22:45:33 espie Exp $ */
+
+/*
+ * Copyright (c) 2003 Marc Espie
+ * 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. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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/param.h>
+#include <sys/syscall.h>
+#include <sys/signalvar.h>
+#include <sys/mount.h>
+#include <sys/syscallargs.h>
+#include <sys/fcntl.h>
+#include <compat/common/compat_util.h>
+
+void aout_compat_setup(struct exec_package *epp);
+
+extern char sigcode[], esigcode[];
+
+struct sysent aout_sysent[SYS_MAXSYSCALL];
+
+struct emul emul_aout = {
+	"native",
+	NULL,
+	sendsig,
+	SYS_syscall,
+	SYS_MAXSYSCALL,
+	NULL,
+#ifdef SYSCALL_DEBUG
+	syscallnames,
+#else
+	NULL,
+#endif
+	0,
+	copyargs,
+	setregs,
+	NULL,
+	sigcode,
+	esigcode,
+};
+
+#ifdef	syscallarg
+#undef	syscallarg
+#endif
+
+#define	syscallarg(x)							\
+	union {								\
+		register_t pad;						\
+		struct { x datum; } le;					\
+		struct {						\
+			int8_t pad[ (sizeof (register_t) < sizeof (x))	\
+				? 0					\
+				: sizeof (register_t) - sizeof (x)];	\
+			x datum;					\
+		} be;							\
+	}
+
+
+struct aout_sys_open_args {
+	syscallarg(char *) path;
+	syscallarg(int) flags;
+	syscallarg(int) mode;
+};
+
+struct aout_sys_link_args {
+	syscallarg(char *) path;
+	syscallarg(char *) link;
+};
+
+struct aout_sys_unlink_args {
+	syscallarg(char *) path;
+};
+
+struct aout_sys_rename_args {
+	syscallarg(char *) from;
+	syscallarg(char *) to;
+};
+
+int aout_sys_open(struct proc *, void *, register_t *);
+int aout_sys_link(struct proc *, void *, register_t *);
+int aout_sys_unlink(struct proc *, void *, register_t *);
+int aout_sys_rename(struct proc *, void *, register_t *);
+
+const char aout_path[] = "/emul/a.out";
+
+#define AOUT_CHECK_ALT_EXIST(p, sgp, path) \
+    CHECK_ALT_EXIST(p, sgp, aout_path, path)
+
+#define  AOUT_CHECK_ALT_CREAT(p, sgp, path) \
+    CHECK_ALT_CREAT(p, sgp, aout_path, path)
+
+/* XXX We just translate enough calls to allow ldconfig and ld.so to work. */
+
+void
+aout_compat_setup(struct exec_package *epp)
+{
+	if (emul_aout.e_sysent == NULL) {
+		memcpy(aout_sysent, sysent, sizeof aout_sysent); 
+		aout_sysent[SYS_open].sy_call = aout_sys_open;
+		aout_sysent[SYS_link].sy_call = aout_sys_link;
+		aout_sysent[SYS_unlink].sy_call = aout_sys_unlink;
+		aout_sysent[SYS_rename].sy_call = aout_sys_rename;
+		emul_aout.e_sysent = aout_sysent;
+	}
+	epp->ep_emul = &emul_aout;
+}
+
+int
+aout_sys_open(p, v, retval)
+	struct proc *p;
+	void *v;
+	register_t *retval;
+{
+	struct aout_sys_open_args /* {
+		syscallarg(char *) path;
+		syscallarg(int) flags;
+		syscallarg(int) mode;
+	} */ *uap = v;
+	caddr_t sg = stackgap_init(p->p_emul);
+
+	if (SCARG(uap, flags) & O_CREAT)
+		AOUT_CHECK_ALT_CREAT(p, &sg, SCARG(uap, path));
+	else
+		AOUT_CHECK_ALT_EXIST(p, &sg, SCARG(uap, path));
+	return sys_open(p, uap, retval);
+}
+
+int
+aout_sys_link(p, v, retval)
+	struct proc *p;
+	void *v;
+	register_t *retval;
+{
+	struct aout_sys_link_args /* {
+		syscallarg(char *) path;
+		syscallarg(char *) link;
+	} */ *uap = v;
+	caddr_t sg = stackgap_init(p->p_emul);
+
+	AOUT_CHECK_ALT_EXIST(p, &sg, SCARG(uap, path));
+	AOUT_CHECK_ALT_CREAT(p, &sg, SCARG(uap, link));
+	return sys_link(p, uap, retval);
+}
+
+int
+aout_sys_unlink(p, v, retval)
+	struct proc *p;
+	void *v;
+	register_t *retval;
+{
+	struct aout_sys_unlink_args /* {
+		syscallarg(char *) path;
+	} */ *uap = v;
+	caddr_t sg = stackgap_init(p->p_emul);
+
+	AOUT_CHECK_ALT_EXIST(p, &sg, SCARG(uap, path));
+	return sys_unlink(p, uap, retval);
+}
+
+
+int
+aout_sys_rename(p, v, retval)
+	struct proc *p;
+	void *v;
+	register_t *retval;
+{
+	struct aout_sys_rename_args /* {
+		syscallarg(char *) from;
+		syscallarg(char *) to;
+	} */ *uap = v;
+	caddr_t sg = stackgap_init(p->p_emul);
+
+	AOUT_CHECK_ALT_EXIST(p, &sg, SCARG(uap, from));
+	AOUT_CHECK_ALT_CREAT(p, &sg, SCARG(uap, to));
+	return sys_rename(p, uap, retval);
+}
diff --git a/sys/compat/aout/files.aout b/sys/compat/aout/files.aout
new file mode 100644
index 00000000000..131b526ea60
--- /dev/null
+++ b/sys/compat/aout/files.aout
@@ -0,0 +1,6 @@
+#	$OpenBSD: files.aout,v 1.1 2003/06/24 22:45:33 espie Exp $
+#
+# machine-independent a.out compat code.
+# Included by ports that need it.
+
+file	compat/aout/compat_aout.c		compat_aout
diff --git a/sys/compat/common/Makefile b/sys/compat/common/Makefile
index 558d5d3898c..49e3098dc34 100644
--- a/sys/compat/common/Makefile
+++ b/sys/compat/common/Makefile
@@ -1,4 +1,4 @@
-#	$OpenBSD: Makefile,v 1.13 2003/01/30 03:29:49 millert Exp $
+#	$OpenBSD: Makefile,v 1.14 2003/06/24 22:45:33 espie Exp $
 #	$NetBSD: Makefile,v 1.8 1996/05/18 15:52:19 christos Exp $
 
 LIB=	compat
@@ -9,8 +9,8 @@ MACHINE_ARCH=	${XMACHINE_ARCH}
 
 .PATH:	${COMPATDIR}
 
-SRCS=	compat_exec.c compat_util.c compat_dir.c compat_vm.c kern_exit_43.c \
-	kern_ipc_23.c kern_info_09.c kern_info_43.c \
+SRCS=	compat_exec.c compat_util.c compat_dir.c compat_vm.c \
+	kern_exit_43.c kern_ipc_23.c kern_info_09.c kern_info_43.c \
 	kern_resource_43.c kern_sig_43.c tty_43.c uipc_syscalls_43.c \
 	vfs_syscalls_25.c vfs_syscalls_43.c vm_43.c