Add support for executing the FreeBSD 1/i386 a.out binaries on amd64.

In particular:
- implement compat shims for old stat(2) variants and ogetdirentries(2);
- implement delivery of signals with ancient stack frame layout and
  corresponding sigreturn(2);
- implement old getpagesize(2);
- provide a user-mode trampoline and LDT call gate for lcall $7,$0;
- port a.out image activator and connect it to the build as a module
  on amd64.

The changes are hidden under COMPAT_43.

MFC after:   1 month

1 files changed, 97 insertions, 3 deletions

diff --git a/sys/compat/freebsd32/freebsd32_misc.c b/sys/compat/freebsd32/freebsd32_misc.c
index e751147..5772c0e 100644
--- a/sys/compat/freebsd32/freebsd32_misc.c
+++ b/sys/compat/freebsd32/freebsd32_misc.c
@@ -1454,6 +1454,29 @@ freebsd32_ftruncate(struct thread *td, struct freebsd32_ftruncate_args *uap)
 	return (ftruncate(td, &ap));
 }
 
+#ifdef COMPAT_43
+int
+ofreebsd32_getdirentries(struct thread *td,
+    struct ofreebsd32_getdirentries_args *uap)
+{
+	struct ogetdirentries_args ap;
+	int error;
+	long loff;
+	int32_t loff_cut;
+
+	ap.fd = uap->fd;
+	ap.buf = uap->buf;
+	ap.count = uap->count;
+	ap.basep = NULL;
+	error = kern_ogetdirentries(td, &ap, &loff);
+	if (error == 0) {
+		loff_cut = loff;
+		error = copyout(&loff_cut, uap->basep, sizeof(int32_t));
+	}
+	return (error);
+}
+#endif
+
 int
 freebsd32_getdirentries(struct thread *td,
     struct freebsd32_getdirentries_args *uap)
@@ -1638,6 +1661,29 @@ copy_stat(struct stat *in, struct stat32 *out)
 	TS_CP(*in, *out, st_birthtim);
 }
 
+#ifdef COMPAT_43
+static void
+copy_ostat(struct stat *in, struct ostat32 *out)
+{
+
+	CP(*in, *out, st_dev);
+	CP(*in, *out, st_ino);
+	CP(*in, *out, st_mode);
+	CP(*in, *out, st_nlink);
+	CP(*in, *out, st_uid);
+	CP(*in, *out, st_gid);
+	CP(*in, *out, st_rdev);
+	CP(*in, *out, st_size);
+	TS_CP(*in, *out, st_atim);
+	TS_CP(*in, *out, st_mtim);
+	TS_CP(*in, *out, st_ctim);
+	CP(*in, *out, st_blksize);
+	CP(*in, *out, st_blocks);
+	CP(*in, *out, st_flags);
+	CP(*in, *out, st_gen);
+}
+#endif
+
 int
 freebsd32_stat(struct thread *td, struct freebsd32_stat_args *uap)
 {
@@ -1653,6 +1699,23 @@ freebsd32_stat(struct thread *td, struct freebsd32_stat_args *uap)
 	return (error);
 }
 
+#ifdef COMPAT_43
+int
+ofreebsd32_stat(struct thread *td, struct ofreebsd32_stat_args *uap)
+{
+	struct stat sb;
+	struct ostat32 sb32;
+	int error;
+
+	error = kern_stat(td, uap->path, UIO_USERSPACE, &sb);
+	if (error)
+		return (error);
+	copy_ostat(&sb, &sb32);
+	error = copyout(&sb32, uap->ub, sizeof (sb32));
+	return (error);
+}
+#endif
+
 int
 freebsd32_fstat(struct thread *td, struct freebsd32_fstat_args *uap)
 {
@@ -1668,6 +1731,23 @@ freebsd32_fstat(struct thread *td, struct freebsd32_fstat_args *uap)
 	return (error);
 }
 
+#ifdef COMPAT_43
+int
+ofreebsd32_fstat(struct thread *td, struct ofreebsd32_fstat_args *uap)
+{
+	struct stat ub;
+	struct ostat32 ub32;
+	int error;
+
+	error = kern_fstat(td, uap->fd, &ub);
+	if (error)
+		return (error);
+	copy_ostat(&ub, &ub32);
+	error = copyout(&ub32, uap->ub, sizeof(ub32));
+	return (error);
+}
+#endif
+
 int
 freebsd32_fstatat(struct thread *td, struct freebsd32_fstatat_args *uap)
 {
@@ -1698,9 +1778,23 @@ freebsd32_lstat(struct thread *td, struct freebsd32_lstat_args *uap)
 	return (error);
 }
 
-/*
- * MPSAFE
- */
+#ifdef COMPAT_43
+int
+ofreebsd32_lstat(struct thread *td, struct ofreebsd32_lstat_args *uap)
+{
+	struct stat sb;
+	struct ostat32 sb32;
+	int error;
+
+	error = kern_lstat(td, uap->path, UIO_USERSPACE, &sb);
+	if (error)
+		return (error);
+	copy_ostat(&sb, &sb32);
+	error = copyout(&sb32, uap->ub, sizeof (sb32));
+	return (error);
+}
+#endif
+
 int
 freebsd32_sysctl(struct thread *td, struct freebsd32_sysctl_args *uap)
 {