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

6 files changed, 124 insertions, 17 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)
 {
diff --git a/sys/compat/freebsd32/syscalls.master b/sys/compat/freebsd32/syscalls.master
index 8a4cadf..da42133 100644
--- a/sys/compat/freebsd32/syscalls.master
+++ b/sys/compat/freebsd32/syscalls.master
@@ -117,9 +117,11 @@
 35	AUE_FCHFLAGS	NOPROTO	{ int fchflags(int fd, int flags); }
 36	AUE_SYNC	NOPROTO	{ int sync(void); }
 37	AUE_KILL	NOPROTO	{ int kill(int pid, int signum); }
-38	AUE_STAT	UNIMPL	ostat
+38	AUE_STAT	COMPAT	{ int freebsd32_stat(char *path, \
+				    struct ostat32 *ub); }
 39	AUE_GETPPID	NOPROTO	{ pid_t getppid(void); }
-40	AUE_LSTAT	UNIMPL	olstat
+40	AUE_LSTAT	COMPAT	{ int freebsd32_lstat(char *path, \
+				    struct ostat *ub); }
 41	AUE_DUP		NOPROTO	{ int dup(u_int fd); }
 42	AUE_PIPE	NOPROTO	{ int pipe(void); }
 43	AUE_GETEGID	NOPROTO	{ gid_t getegid(void); }
@@ -153,9 +155,11 @@
 60	AUE_UMASK	NOPROTO	{ int umask(int newmask); } umask \
 				    umask_args int
 61	AUE_CHROOT	NOPROTO	{ int chroot(char *path); }
-62	AUE_FSTAT	OBSOL	ofstat
+62	AUE_FSTAT	COMPAT	{ int freebsd32_fstat(int fd, \
+				    struct ostat32 *ub); }
 63	AUE_NULL	OBSOL	ogetkerninfo
-64	AUE_NULL	OBSOL	ogetpagesize
+64	AUE_NULL	COMPAT	{ int freebsd32_getpagesize( \
+				    int32_t dummy); }
 65	AUE_MSYNC	NOPROTO	{ int msync(void *addr, size_t len, \
 				    int flags); }
 66	AUE_VFORK	NOPROTO	{ int vfork(void); }
@@ -210,7 +214,8 @@
 100	AUE_GETPRIORITY	NOPROTO	{ int getpriority(int which, int who); }
 101	AUE_NULL	OBSOL	osend
 102	AUE_NULL	OBSOL	orecv
-103	AUE_NULL	OBSOL	osigreturn
+103	AUE_NULL	COMPAT	{ int freebsd32_sigreturn( \
+				    struct ia32_sigcontext3 *sigcntxp); }
 104	AUE_BIND	NOPROTO	{ int bind(int s, caddr_t name, \
 				    int namelen); }
 105	AUE_SETSOCKOPT	NOPROTO	{ int setsockopt(int s, int level, \
@@ -292,7 +297,8 @@
 ; 155 is initialized by the NFS code, if present.
 ; XXX this is a problem!!!
 155	AUE_NFS_SVC	UNIMPL	nfssvc
-156	AUE_GETDIRENTRIES	OBSOL	ogetdirentries
+156	AUE_GETDIRENTRIES COMPAT { int freebsd32_getdirentries(int fd, \
+				    char *buf, u_int count, uint32_t *basep); }
 157	AUE_STATFS	COMPAT4	{ int freebsd32_statfs(char *path, \
 				    struct statfs32 *buf); }
 158	AUE_FSTATFS	COMPAT4	{ int freebsd32_fstatfs(int fd, \
diff --git a/sys/compat/ia32/ia32_genassym.c b/sys/compat/ia32/ia32_genassym.c
index 84fb648..5462a8b 100644
--- a/sys/compat/ia32/ia32_genassym.c
+++ b/sys/compat/ia32/ia32_genassym.c
@@ -13,6 +13,9 @@ __FBSDID("$FreeBSD$");
 
 ASSYM(IA32_SIGF_HANDLER, offsetof(struct ia32_sigframe, sf_ah));
 ASSYM(IA32_SIGF_UC, offsetof(struct ia32_sigframe, sf_uc));
+#ifdef COMPAT_43
+ASSYM(IA32_SIGF_SC, offsetof(struct ia32_sigframe3, sf_siginfo.si_sc));
+#endif
 ASSYM(IA32_UC_GS, offsetof(struct ia32_ucontext, uc_mcontext.mc_gs));
 ASSYM(IA32_UC_FS, offsetof(struct ia32_ucontext, uc_mcontext.mc_fs));
 ASSYM(IA32_UC_ES, offsetof(struct ia32_ucontext, uc_mcontext.mc_es));
diff --git a/sys/compat/ia32/ia32_signal.h b/sys/compat/ia32/ia32_signal.h
index 757e384..0c54caf 100644
--- a/sys/compat/ia32/ia32_signal.h
+++ b/sys/compat/ia32/ia32_signal.h
@@ -112,7 +112,7 @@ struct ia32_ucontext4 {
 };
 #endif
 
-#ifdef COMPAT_FREEBSD3
+#ifdef COMPAT_43
 struct ia32_sigcontext3 {
 	u_int32_t	sc_onstack;
 	u_int32_t	sc_mask;
@@ -165,7 +165,7 @@ struct ia32_sigframe {
 	struct siginfo32	sf_si;		/* = *sf_siginfo (SA_SIGINFO case) */
 };
 
-#ifdef COMPAT_FREEBSD3
+#ifdef COMPAT_43
 struct ia32_siginfo3 {
 	struct ia32_sigcontext3 si_sc;
 	int			si_signo;
@@ -186,10 +186,15 @@ struct ksiginfo;
 struct image_params;
 extern char ia32_sigcode[];
 extern char freebsd4_ia32_sigcode[];
+extern char ia32_osigcode[];
+extern char lcall_tramp;
 extern int sz_ia32_sigcode;
 extern int sz_freebsd4_ia32_sigcode;
-extern void ia32_sendsig(sig_t, struct ksiginfo *, sigset_t *);
-extern void ia32_setregs(struct thread *td, struct image_params *imgp,
+extern int sz_ia32_osigcode;
+extern int sz_lcall_tramp;
+void ia32_sendsig(sig_t, struct ksiginfo *, sigset_t *);
+void ia32_setregs(struct thread *td, struct image_params *imgp,
     u_long stack);
+int setup_lcall_gate(void);
 
 #endif
diff --git a/sys/compat/ia32/ia32_sysvec.c b/sys/compat/ia32/ia32_sysvec.c
index a7790ef..c7edac4 100644
--- a/sys/compat/ia32/ia32_sysvec.c
+++ b/sys/compat/ia32/ia32_sysvec.c
@@ -95,14 +95,12 @@ CTASSERT(sizeof(struct ia32_sigframe4) == 408);
 
 extern const char *freebsd32_syscallnames[];
 
-static void ia32_fixlimit(struct rlimit *rl, int which);
-
 SYSCTL_NODE(_compat, OID_AUTO, ia32, CTLFLAG_RW, 0, "ia32 mode");
 
 static u_long	ia32_maxdsiz = IA32_MAXDSIZ;
 SYSCTL_ULONG(_compat_ia32, OID_AUTO, maxdsiz, CTLFLAG_RW, &ia32_maxdsiz, 0, "");
 TUNABLE_ULONG("compat.ia32.maxdsiz", &ia32_maxdsiz);
-static u_long	ia32_maxssiz = IA32_MAXSSIZ;
+u_long	ia32_maxssiz = IA32_MAXSSIZ;
 SYSCTL_ULONG(_compat_ia32, OID_AUTO, maxssiz, CTLFLAG_RW, &ia32_maxssiz, 0, "");
 TUNABLE_ULONG("compat.ia32.maxssiz", &ia32_maxssiz);
 static u_long	ia32_maxvmem = IA32_MAXVMEM;
@@ -206,7 +204,7 @@ elf32_dump_thread(struct thread *td __unused, void *dst __unused,
 {
 }
 
-static void
+void
 ia32_fixlimit(struct rlimit *rl, int which)
 {
 
diff --git a/sys/compat/ia32/ia32_util.h b/sys/compat/ia32/ia32_util.h
index 4355daa..f153492 100644
--- a/sys/compat/ia32/ia32_util.h
+++ b/sys/compat/ia32/ia32_util.h
@@ -58,5 +58,6 @@
 struct syscall_args;
 int ia32_fetch_syscall_args(struct thread *td, struct syscall_args *sa);
 void ia32_set_syscall_retval(struct thread *, int);
+void ia32_fixlimit(struct rlimit *rl, int which);
 
 #endif