Reviewed by: Luoqi Chen, Jordan Hubbard

Submitted by:	 "Richard Seaman, Jr." <lists@tar.com>
Obtained from:	linux :-)

Code to allow Linux Threads to run under FreeBSD.

By default not enabled
This code is dependent on the conditional
COMPAT_LINUX_THREADS (suggested by Garret)
This is not yet a 'real' option but will be within some number of hours.

25 files changed, 639 insertions, 46 deletions

diff --git a/bin/ps/keyword.c b/bin/ps/keyword.c
index a0c60b11b9f1..023c55df3ff6 100644
--- a/bin/ps/keyword.c
+++ b/bin/ps/keyword.c
@@ -36,7 +36,7 @@
 static char sccsid[] = "@(#)keyword.c	8.5 (Berkeley) 4/2/94";
 #else
 static const char rcsid[] =
-	"$Id: keyword.c,v 1.19 1998/05/25 05:07:17 steve Exp $";
+	"$Id: keyword.c,v 1.20 1998/09/14 08:32:20 dfr Exp $";
 #endif
 #endif /* not lint */
 
@@ -157,10 +157,12 @@ VAR var[] = {
 	{"ruser", "RUSER", NULL, LJUST|DSIZ, runame, s_runame, USERLEN},
 	{"sess", "SESS", NULL, 0, evar, NULL, 6, EOFF(e_sess), KPTR, "lx"},
 	{"sig", "PENDING", NULL, 0, pvar, NULL, 8, POFF(p_siglist), INT, "x"},
+#ifndef COMPAT_LINUX_THREADS
 	{"sigcatch", "CAUGHT",
 		NULL, 0, pvar, NULL, 8, POFF(p_sigcatch), UINT, "x"},
 	{"sigignore", "IGNORED",
 		NULL, 0, pvar, NULL, 8, POFF(p_sigignore), UINT, "x"},
+#endif /* COMPAT_LINUX_THREADS */
 	{"sigmask", "BLOCKED",
 		NULL, 0, pvar, NULL, 8, POFF(p_sigmask), UINT, "x"},
 	{"sl", "SL", NULL, 0, pvar, NULL, 3, POFF(p_slptime), UINT, "d"},
diff --git a/lib/libc/i386/sys/sigsuspend.S b/lib/libc/i386/sys/sigsuspend.S
index 660eabf85411..f85b2e1929f1 100644
--- a/lib/libc/i386/sys/sigsuspend.S
+++ b/lib/libc/i386/sys/sigsuspend.S
@@ -33,12 +33,12 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id$
+ *	$Id: sigsuspend.S,v 1.6 1997/02/22 14:59:40 peter Exp $
  */
 
 #if defined(SYSLIBC_RCS) && !defined(lint)
 	.text
-	.asciz "$Id$"
+	.asciz "$Id: sigsuspend.S,v 1.6 1997/02/22 14:59:40 peter Exp $"
 #endif /* SYSLIBC_RCS and not lint */
 
 #include "SYS.h"
@@ -50,7 +50,9 @@ err:
 #ifdef _THREAD_SAFE
 ENTRY(_thread_sys_sigsuspend)
 #else
-ENTRY(sigsuspend)
+ENTRY(_sigsuspend)
+	.weak CNAME(sigsuspend)	; 
+	.set CNAME(sigsuspend), CNAME(_sigsuspend) ; 
 #endif
 	movl	4(%esp),%eax		# fetch mask arg
 	movl	(%eax),%eax		# indirect to mask arg
diff --git a/sys/alpha/linux/linux.h b/sys/alpha/linux/linux.h
index 691ed550f336..820028fb5d06 100644
--- a/sys/alpha/linux/linux.h
+++ b/sys/alpha/linux/linux.h
@@ -25,7 +25,7 @@
  * (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: linux.h,v 1.23 1998/10/05 16:37:36 jfieber Exp $
+ *	$Id: linux.h,v 1.24 1998/11/12 00:42:08 jkh Exp $
  */
 
 #ifndef _I386_LINUX_LINUX_H_
@@ -418,6 +418,7 @@ struct trapframe;
 #define LINUX_MAP_PRIVATE	0x0002
 #define LINUX_MAP_FIXED		0x0010
 #define LINUX_MAP_ANON		0x0020
+#define LINUX_MAP_GROWSDOWN     0x0100
 
 /* SystemV ipc defines */
 #define LINUX_SEMOP		1
diff --git a/sys/alpha/linux/linux_dummy.c b/sys/alpha/linux/linux_dummy.c
index 30a0dba49449..6a7ce1e82802 100644
--- a/sys/alpha/linux/linux_dummy.c
+++ b/sys/alpha/linux/linux_dummy.c
@@ -25,7 +25,7 @@
  * (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: linux_dummy.c,v 1.7 1997/10/29 08:17:09 kato Exp $
+ *  $Id: linux_dummy.c,v 1.8 1997/11/06 19:28:52 phk Exp $
  */
 
 #include <sys/param.h>
@@ -212,13 +212,6 @@ linux_sysinfo(struct proc *p, struct linux_sysinfo_args *args)
 }
 
 int
-linux_clone(struct proc *p, struct linux_clone_args *args)
-{
-    printf("Linux-emul(%d): clone() not supported\n", p->p_pid);
-    return ENOSYS;
-}
-
-int
 linux_uname(struct proc *p, struct linux_uname_args *args)
 {
     printf("Linux-emul(%d): uname() not supported\n", p->p_pid);
diff --git a/sys/alpha/linux/linux_sysvec.c b/sys/alpha/linux/linux_sysvec.c
index 188e3d5a5b69..b8639516ef86 100644
--- a/sys/alpha/linux/linux_sysvec.c
+++ b/sys/alpha/linux/linux_sysvec.c
@@ -25,7 +25,7 @@
  * (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: linux_sysvec.c,v 1.39 1998/12/14 18:54:01 dt Exp $
+ *  $Id: linux_sysvec.c,v 1.40 1998/12/16 16:28:57 bde Exp $
  */
 
 /* XXX we use functions that might not exist. */
@@ -50,6 +50,10 @@
 #include <vm/vm_prot.h>
 #include <vm/vm_page.h>
 #include <vm/vm_extern.h>
+#ifdef COMPAT_LINUX_THREADS
+#include <sys/lock.h>             /* needed, for now, by vm_map.h */
+#include <vm/vm_map.h>            /* needed, for now, for VM_STACK defines */
+#endif /* COMPAT_LINUX_THREADS */
 #include <sys/exec.h>
 #include <sys/kernel.h>
 #include <sys/module.h>
@@ -217,7 +221,24 @@ linux_sendsig(sig_t catcher, int sig, int mask, u_long code)
 	 *	and the stack can not be grown. useracc will return FALSE
 	 *	if access is denied.
 	 */
+#ifdef COMPAT_LINUX_THREADS
+#ifdef USE_VM_STACK
+#ifndef USE_VM_STACK_FOR_EXEC
+	if ((((caddr_t)fp > p->p_vmspace->vm_maxsaddr &&
+	      (caddr_t)fp < (caddr_t)USRSTACK &&
+	      grow(p, (int)fp) == FALSE) ||
+	     (((caddr_t)fp <= p->p_vmspace->vm_maxsaddr ||
+	       (caddr_t)fp >= (caddr_t)USRSTACK) &&
+	      grow_stack (p, (int)fp) == FALSE)) ||
+#else
+	if ((grow_stack (p, (int)fp) == FALSE) ||
+#endif
+#else
+#endif /* COMPAT_LINUX_THREADS */
 	if ((grow(p, (int)fp) == FALSE) ||
+#ifdef COMPAT_LINUX_THREADS
+#endif
+#endif /* COMPAT_LINUX_THREADS */
 	    (useracc((caddr_t)fp, sizeof (struct linux_sigframe), B_WRITE) == FALSE)) {
 		/*
 		 * Process has trashed its stack; give it an illegal
diff --git a/sys/alpha/linux/syscalls.master b/sys/alpha/linux/syscalls.master
index 912cb3244597..3b24f1384627 100644
--- a/sys/alpha/linux/syscalls.master
+++ b/sys/alpha/linux/syscalls.master
@@ -1,4 +1,4 @@
-	$Id: syscalls.master,v 1.11 1998/06/09 03:28:14 bde Exp $
+	$Id: syscalls.master,v 1.12 1998/07/10 22:30:08 jkh Exp $
 
 ;	@(#)syscalls.master	8.1 (Berkeley) 7/19/93
 ; System call name/number master file (or rather, slave, from LINUX).
@@ -171,7 +171,7 @@
 			    caddr_t ptr); }
 118	NOPROTO	LINUX	{ int fsync(int fd); }
 119	STD	LINUX	{ int linux_sigreturn(struct linux_sigcontext *scp); }
-120	STD	LINUX	{ int linux_clone(void); }
+120	STD	LINUX	{ int linux_clone(int flags, void *stack); }
 121	NOPROTO	LINUX	{ int setdomainname(char *name, \
 			    int len); }
 122	STD	LINUX	{ int linux_newuname(struct linux_newuname_t *buf); }
diff --git a/sys/compat/linux/linux_misc.c b/sys/compat/linux/linux_misc.c
index 68fee0f657d6..4b441fd81370 100644
--- a/sys/compat/linux/linux_misc.c
+++ b/sys/compat/linux/linux_misc.c
@@ -25,7 +25,7 @@
  * (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: linux_misc.c,v 1.46 1998/12/04 22:54:50 archie Exp $
+ *  $Id: linux_misc.c,v 1.47 1998/12/10 13:47:18 jkh Exp $
  */
 
 #include <sys/param.h>
@@ -41,6 +41,9 @@
 #include <sys/resourcevar.h>
 #include <sys/stat.h>
 #include <sys/sysctl.h>
+#ifdef COMPAT_LINUX_THREADS
+#include <sys/unistd.h>
+#endif /* COMPAT_LINUX_THREADS */
 #include <sys/vnode.h>
 #include <sys/wait.h>
 #include <sys/time.h>
@@ -560,6 +563,84 @@ linux_fork(struct proc *p, struct linux_fork_args *args)
     return 0;
 }
 
+#ifndef COMPAT_LINUX_THREADS
+int
+linux_clone(struct proc *p, struct linux_clone_args *args)
+{
+    printf("linux_clone(%d): Not enabled\n", p->p_pid);
+    return (EOPNOTSUPP);
+}
+
+#else
+#define CLONE_VM	0x100
+#define CLONE_FS	0x200
+#define CLONE_FILES	0x400
+#define CLONE_SIGHAND	0x800
+#define CLONE_PID	0x1000
+
+int
+linux_clone(struct proc *p, struct linux_clone_args *args)
+{
+    int error, ff = RFPROC;
+    struct proc *p2;
+    int            growable;
+    int            initstacksize;
+    int            maxstacksize;
+    int            exit_signal;
+    vm_map_entry_t entry;
+    vm_map_t       map;
+    vm_offset_t    start;
+    struct rfork_args rf_args;
+
+#ifdef SMP
+    printf("linux_clone(%d): does not work with SMP yet\n", p->p_pid);
+    return (EOPNOTSUPP);
+#endif
+#ifdef DEBUG
+    if (args->flags & CLONE_PID)
+	printf("linux_clone(%d): CLONE_PID not yet supported\n", p->p_pid);
+    printf ("linux_clone(%d): invoked with flags %x and stack %x\n", p->p_pid,
+	     (unsigned int)args->flags, (unsigned int)args->stack);
+#endif
+
+    if (!args->stack)
+        return (EINVAL);
+    exit_signal = args->flags & 0x000000ff;
+    if (exit_signal >= LINUX_NSIG)
+	return EINVAL;
+    exit_signal = linux_to_bsd_signal[exit_signal];
+
+    /* RFTHREAD probably not necessary here, but it shouldn't hurt either */
+    ff |= RFTHREAD;
+
+    if (args->flags & CLONE_VM)
+	ff |= RFMEM;
+    if (args->flags & CLONE_SIGHAND)
+	ff |= RFSIGSHARE;
+    if (!(args->flags & CLONE_FILES))
+	ff |= RFFDG;
+
+    error = 0;
+    start = 0;
+
+    rf_args.flags = ff;
+    if (error = rfork(p, &rf_args))
+	return error;
+
+    p2 = pfind(p->p_retval[0]);
+    if (p2 == 0)
+ 	return ESRCH;
+    
+    p2->p_sigparent = exit_signal;
+    p2->p_md.md_regs->tf_esp = (unsigned int)args->stack;
+
+#ifdef DEBUG
+    printf ("linux_clone(%d): successful rfork to %d\n", p->p_pid, p2->p_pid);
+#endif
+    return 0;
+}
+
+#endif /* COMPAT_LINUX_THREADS */
 /* XXX move */
 struct linux_mmap_argv {
 	linux_caddr_t addr;
@@ -570,6 +651,11 @@ struct linux_mmap_argv {
 	int pos;
 };
 
+#ifdef COMPAT_LINUX_THREADS
+#define STACK_SIZE  (2 * 1024 * 1024)
+#define GUARD_SIZE  (4 * PAGE_SIZE)
+
+#endif /* COMPAT_LINUX_THREADS */
 int
 linux_mmap(struct proc *p, struct linux_mmap_args *args)
 {
@@ -602,8 +688,70 @@ linux_mmap(struct proc *p, struct linux_mmap_args *args)
 	bsd_args.flags |= MAP_FIXED;
     if (linux_args.flags & LINUX_MAP_ANON)
 	bsd_args.flags |= MAP_ANON;
+#ifndef COMPAT_LINUX_THREADS
     bsd_args.addr = linux_args.addr;
     bsd_args.len = linux_args.len;
+#else
+
+#if !defined(USE_VM_STACK) && !defined(USE_VM_STACK_FOR_EXEC)
+    /* Linux Threads will map into the proc stack space, unless
+       we prevent it.  This causes problems if we're not using
+       our VM_STACK options.
+    */
+    if ((unsigned int)linux_args.addr + linux_args.len > (USRSTACK - MAXSSIZ))
+        return (EINVAL);
+#endif
+
+    if (linux_args.flags & LINUX_MAP_GROWSDOWN) {
+
+#ifdef USE_VM_STACK
+        /* USE_VM_STACK is defined (or not) in vm/vm_map.h */
+        bsd_args.flags |= MAP_STACK;      
+#endif
+
+	/* The linux MAP_GROWSDOWN option does not limit auto
+	   growth of the region.  Linux mmap with this option
+	   takes as addr the inital BOS, and as len, the initial
+	   region size.  It can then grow down from addr without
+	   limit.  However, linux threads has an implicit internal
+	   limit to stack size of STACK_SIZE.  Its just not
+	   enforced explicitly in linux.  But, here we impose
+	   a limit of (STACK_SIZE - GUARD_SIZE) on the stack
+	   region, since we can do this with our mmap.
+
+	   Our mmap with MAP_STACK takes addr as the maximum
+	   downsize limit on BOS, and as len the max size of
+	   the region.  It them maps the top SGROWSIZ bytes,
+	   and autgrows the region down, up to the limit
+	   in addr.
+
+	   If we don't use the MAP_STACK option, the effect
+	   of this code is to allocate a stack region of a
+	   fixed size of (STACK_SIZE - GUARD_SIZE).
+	*/
+
+	/* This gives us TOS */
+        bsd_args.addr = linux_args.addr + linux_args.len;
+
+	/* This gives us our maximum stack size */
+	if (linux_args.len > STACK_SIZE - GUARD_SIZE)
+	    bsd_args.len = linux_args.len;
+	else
+	    bsd_args.len  = STACK_SIZE - GUARD_SIZE;
+
+	/* This gives us a new BOS.  If we're using VM_STACK, then
+	   mmap will just map the top SGROWSIZ bytes, and let
+	   the stack grow down to the limit at BOS.  If we're
+	   not using VM_STACK we map the full stack, since we
+	   don't have a way to autogrow it.
+	*/
+	bsd_args.addr -= bsd_args.len;
+
+    } else {
+        bsd_args.addr = linux_args.addr;
+	bsd_args.len  = linux_args.len;
+    }
+#endif /* COMPAT_LINUX_THREADS */
     bsd_args.prot = linux_args.prot | PROT_READ;	/* always required */
     bsd_args.fd = linux_args.fd;
     bsd_args.pos = linux_args.pos;
@@ -830,11 +978,25 @@ linux_waitpid(struct proc *p, struct linux_waitpid_args *args)
 #endif
     tmp.pid = args->pid;
     tmp.status = args->status;
+#ifndef COMPAT_LINUX_THREADS
     tmp.options = args->options;
+#else
+    /* This filters out the linux option _WCLONE.  I don't
+       think we need it, but I could be wrong.  If we need
+       it, we need to fix wait4, since it will give us an
+       error return of EINVAL if we pass in _WCLONE, and
+       of course, it won't do anything with it.
+    */
+    tmp.options = (args->options & (WNOHANG | WUNTRACED));
+#endif /* COMPAT_LINUX_THREADS */
     tmp.rusage = NULL;
 
     if (error = wait4(p, &tmp))
+#ifndef COMPAT_LINUX_THREADS
 	return error;
+#else
+  	return error;
+#endif /* COMPAT_LINUX_THREADS */
     if (args->status) {
 	if (error = copyin(args->status, &tmpstat, sizeof(int)))
 	    return error;
@@ -867,7 +1029,17 @@ linux_wait4(struct proc *p, struct linux_wait4_args *args)
 #endif
     tmp.pid = args->pid;
     tmp.status = args->status;
+#ifndef COMPAT_LINUX_THREADS
     tmp.options = args->options;
+#else
+    /* This filters out the linux option _WCLONE.  I don't
+       think we need it, but I could be wrong.  If we need
+       it, we need to fix wait4, since it will give us an
+       error return of EINVAL if we pass in _WCLONE, and
+       of course, it won't do anything with it.
+    */
+    tmp.options = (args->options & (WNOHANG | WUNTRACED));
+#endif /* COMPAT_LINUX_THREADS */
     tmp.rusage = args->rusage;
 
     if (error = wait4(p, &tmp))
diff --git a/sys/i386/linux/linux.h b/sys/i386/linux/linux.h
index 691ed550f336..820028fb5d06 100644
--- a/sys/i386/linux/linux.h
+++ b/sys/i386/linux/linux.h
@@ -25,7 +25,7 @@
  * (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: linux.h,v 1.23 1998/10/05 16:37:36 jfieber Exp $
+ *	$Id: linux.h,v 1.24 1998/11/12 00:42:08 jkh Exp $
  */
 
 #ifndef _I386_LINUX_LINUX_H_
@@ -418,6 +418,7 @@ struct trapframe;
 #define LINUX_MAP_PRIVATE	0x0002
 #define LINUX_MAP_FIXED		0x0010
 #define LINUX_MAP_ANON		0x0020
+#define LINUX_MAP_GROWSDOWN     0x0100
 
 /* SystemV ipc defines */
 #define LINUX_SEMOP		1
diff --git a/sys/i386/linux/linux_dummy.c b/sys/i386/linux/linux_dummy.c
index 30a0dba49449..6a7ce1e82802 100644
--- a/sys/i386/linux/linux_dummy.c
+++ b/sys/i386/linux/linux_dummy.c
@@ -25,7 +25,7 @@
  * (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: linux_dummy.c,v 1.7 1997/10/29 08:17:09 kato Exp $
+ *  $Id: linux_dummy.c,v 1.8 1997/11/06 19:28:52 phk Exp $
  */
 
 #include <sys/param.h>
@@ -212,13 +212,6 @@ linux_sysinfo(struct proc *p, struct linux_sysinfo_args *args)
 }
 
 int
-linux_clone(struct proc *p, struct linux_clone_args *args)
-{
-    printf("Linux-emul(%d): clone() not supported\n", p->p_pid);
-    return ENOSYS;
-}
-
-int
 linux_uname(struct proc *p, struct linux_uname_args *args)
 {
     printf("Linux-emul(%d): uname() not supported\n", p->p_pid);
diff --git a/sys/i386/linux/linux_misc.c b/sys/i386/linux/linux_misc.c
index 68fee0f657d6..4b441fd81370 100644
--- a/sys/i386/linux/linux_misc.c
+++ b/sys/i386/linux/linux_misc.c
@@ -25,7 +25,7 @@
  * (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: linux_misc.c,v 1.46 1998/12/04 22:54:50 archie Exp $
+ *  $Id: linux_misc.c,v 1.47 1998/12/10 13:47:18 jkh Exp $
  */
 
 #include <sys/param.h>
@@ -41,6 +41,9 @@
 #include <sys/resourcevar.h>
 #include <sys/stat.h>
 #include <sys/sysctl.h>
+#ifdef COMPAT_LINUX_THREADS
+#include <sys/unistd.h>
+#endif /* COMPAT_LINUX_THREADS */
 #include <sys/vnode.h>
 #include <sys/wait.h>
 #include <sys/time.h>
@@ -560,6 +563,84 @@ linux_fork(struct proc *p, struct linux_fork_args *args)
     return 0;
 }
 
+#ifndef COMPAT_LINUX_THREADS
+int
+linux_clone(struct proc *p, struct linux_clone_args *args)
+{
+    printf("linux_clone(%d): Not enabled\n", p->p_pid);
+    return (EOPNOTSUPP);
+}
+
+#else
+#define CLONE_VM	0x100
+#define CLONE_FS	0x200
+#define CLONE_FILES	0x400
+#define CLONE_SIGHAND	0x800
+#define CLONE_PID	0x1000
+
+int
+linux_clone(struct proc *p, struct linux_clone_args *args)
+{
+    int error, ff = RFPROC;
+    struct proc *p2;
+    int            growable;
+    int            initstacksize;
+    int            maxstacksize;
+    int            exit_signal;
+    vm_map_entry_t entry;
+    vm_map_t       map;
+    vm_offset_t    start;
+    struct rfork_args rf_args;
+
+#ifdef SMP
+    printf("linux_clone(%d): does not work with SMP yet\n", p->p_pid);
+    return (EOPNOTSUPP);
+#endif
+#ifdef DEBUG
+    if (args->flags & CLONE_PID)
+	printf("linux_clone(%d): CLONE_PID not yet supported\n", p->p_pid);
+    printf ("linux_clone(%d): invoked with flags %x and stack %x\n", p->p_pid,
+	     (unsigned int)args->flags, (unsigned int)args->stack);
+#endif
+
+    if (!args->stack)
+        return (EINVAL);
+    exit_signal = args->flags & 0x000000ff;
+    if (exit_signal >= LINUX_NSIG)
+	return EINVAL;
+    exit_signal = linux_to_bsd_signal[exit_signal];
+
+    /* RFTHREAD probably not necessary here, but it shouldn't hurt either */
+    ff |= RFTHREAD;
+
+    if (args->flags & CLONE_VM)
+	ff |= RFMEM;
+    if (args->flags & CLONE_SIGHAND)
+	ff |= RFSIGSHARE;
+    if (!(args->flags & CLONE_FILES))
+	ff |= RFFDG;
+
+    error = 0;
+    start = 0;
+
+    rf_args.flags = ff;
+    if (error = rfork(p, &rf_args))
+	return error;
+
+    p2 = pfind(p->p_retval[0]);
+    if (p2 == 0)
+ 	return ESRCH;
+    
+    p2->p_sigparent = exit_signal;
+    p2->p_md.md_regs->tf_esp = (unsigned int)args->stack;
+
+#ifdef DEBUG
+    printf ("linux_clone(%d): successful rfork to %d\n", p->p_pid, p2->p_pid);
+#endif
+    return 0;
+}
+
+#endif /* COMPAT_LINUX_THREADS */
 /* XXX move */
 struct linux_mmap_argv {
 	linux_caddr_t addr;
@@ -570,6 +651,11 @@ struct linux_mmap_argv {
 	int pos;
 };
 
+#ifdef COMPAT_LINUX_THREADS
+#define STACK_SIZE  (2 * 1024 * 1024)
+#define GUARD_SIZE  (4 * PAGE_SIZE)
+
+#endif /* COMPAT_LINUX_THREADS */
 int
 linux_mmap(struct proc *p, struct linux_mmap_args *args)
 {
@@ -602,8 +688,70 @@ linux_mmap(struct proc *p, struct linux_mmap_args *args)
 	bsd_args.flags |= MAP_FIXED;
     if (linux_args.flags & LINUX_MAP_ANON)
 	bsd_args.flags |= MAP_ANON;
+#ifndef COMPAT_LINUX_THREADS
     bsd_args.addr = linux_args.addr;
     bsd_args.len = linux_args.len;
+#else
+
+#if !defined(USE_VM_STACK) && !defined(USE_VM_STACK_FOR_EXEC)
+    /* Linux Threads will map into the proc stack space, unless
+       we prevent it.  This causes problems if we're not using
+       our VM_STACK options.
+    */
+    if ((unsigned int)linux_args.addr + linux_args.len > (USRSTACK - MAXSSIZ))
+        return (EINVAL);
+#endif
+
+    if (linux_args.flags & LINUX_MAP_GROWSDOWN) {
+
+#ifdef USE_VM_STACK
+        /* USE_VM_STACK is defined (or not) in vm/vm_map.h */
+        bsd_args.flags |= MAP_STACK;      
+#endif
+
+	/* The linux MAP_GROWSDOWN option does not limit auto
+	   growth of the region.  Linux mmap with this option
+	   takes as addr the inital BOS, and as len, the initial
+	   region size.  It can then grow down from addr without
+	   limit.  However, linux threads has an implicit internal
+	   limit to stack size of STACK_SIZE.  Its just not
+	   enforced explicitly in linux.  But, here we impose
+	   a limit of (STACK_SIZE - GUARD_SIZE) on the stack
+	   region, since we can do this with our mmap.
+
+	   Our mmap with MAP_STACK takes addr as the maximum
+	   downsize limit on BOS, and as len the max size of
+	   the region.  It them maps the top SGROWSIZ bytes,
+	   and autgrows the region down, up to the limit
+	   in addr.
+
+	   If we don't use the MAP_STACK option, the effect
+	   of this code is to allocate a stack region of a
+	   fixed size of (STACK_SIZE - GUARD_SIZE).
+	*/
+
+	/* This gives us TOS */
+        bsd_args.addr = linux_args.addr + linux_args.len;
+
+	/* This gives us our maximum stack size */
+	if (linux_args.len > STACK_SIZE - GUARD_SIZE)
+	    bsd_args.len = linux_args.len;
+	else
+	    bsd_args.len  = STACK_SIZE - GUARD_SIZE;
+
+	/* This gives us a new BOS.  If we're using VM_STACK, then
+	   mmap will just map the top SGROWSIZ bytes, and let
+	   the stack grow down to the limit at BOS.  If we're
+	   not using VM_STACK we map the full stack, since we
+	   don't have a way to autogrow it.
+	*/
+	bsd_args.addr -= bsd_args.len;
+
+    } else {
+        bsd_args.addr = linux_args.addr;
+	bsd_args.len  = linux_args.len;
+    }
+#endif /* COMPAT_LINUX_THREADS */
     bsd_args.prot = linux_args.prot | PROT_READ;	/* always required */
     bsd_args.fd = linux_args.fd;
     bsd_args.pos = linux_args.pos;
@@ -830,11 +978,25 @@ linux_waitpid(struct proc *p, struct linux_waitpid_args *args)
 #endif
     tmp.pid = args->pid;
     tmp.status = args->status;
+#ifndef COMPAT_LINUX_THREADS
     tmp.options = args->options;
+#else
+    /* This filters out the linux option _WCLONE.  I don't
+       think we need it, but I could be wrong.  If we need
+       it, we need to fix wait4, since it will give us an
+       error return of EINVAL if we pass in _WCLONE, and
+       of course, it won't do anything with it.
+    */
+    tmp.options = (args->options & (WNOHANG | WUNTRACED));
+#endif /* COMPAT_LINUX_THREADS */
     tmp.rusage = NULL;
 
     if (error = wait4(p, &tmp))
+#ifndef COMPAT_LINUX_THREADS
 	return error;
+#else
+  	return error;
+#endif /* COMPAT_LINUX_THREADS */
     if (args->status) {
 	if (error = copyin(args->status, &tmpstat, sizeof(int)))
 	    return error;
@@ -867,7 +1029,17 @@ linux_wait4(struct proc *p, struct linux_wait4_args *args)
 #endif
     tmp.pid = args->pid;
     tmp.status = args->status;
+#ifndef COMPAT_LINUX_THREADS
     tmp.options = args->options;
+#else
+    /* This filters out the linux option _WCLONE.  I don't
+       think we need it, but I could be wrong.  If we need
+       it, we need to fix wait4, since it will give us an
+       error return of EINVAL if we pass in _WCLONE, and
+       of course, it won't do anything with it.
+    */
+    tmp.options = (args->options & (WNOHANG | WUNTRACED));
+#endif /* COMPAT_LINUX_THREADS */
     tmp.rusage = args->rusage;
 
     if (error = wait4(p, &tmp))
diff --git a/sys/i386/linux/linux_proto.h b/sys/i386/linux/linux_proto.h
index eedb56606a4c..395d907e4ccb 100644
--- a/sys/i386/linux/linux_proto.h
+++ b/sys/i386/linux/linux_proto.h
@@ -2,7 +2,7 @@
  * System call prototypes.
  *
  * DO NOT EDIT-- this file is automatically generated.
- * created from	Id: syscalls.master,v 1.11 1998/06/09 03:28:14 bde Exp 
+ * created from	Id: syscalls.master,v 1.12 1998/07/10 22:30:08 jkh Exp 
  */
 
 #ifndef _LINUX_SYSPROTO_H_
@@ -301,7 +301,8 @@ struct	linux_sigreturn_args {
 	struct linux_sigcontext *	scp;	char scp_[PAD_(struct linux_sigcontext *)];
 };
 struct	linux_clone_args {
-	register_t dummy;
+	int	flags;	char flags_[PAD_(int)];
+	void *	stack;	char stack_[PAD_(void *)];
 };
 struct	linux_newuname_args {
 	struct linux_newuname_t *	buf;	char buf_[PAD_(struct linux_newuname_t *)];
diff --git a/sys/i386/linux/linux_syscall.h b/sys/i386/linux/linux_syscall.h
index c0b714753156..c88cc7c86623 100644
--- a/sys/i386/linux/linux_syscall.h
+++ b/sys/i386/linux/linux_syscall.h
@@ -2,7 +2,7 @@
  * System call numbers.
  *
  * DO NOT EDIT-- this file is automatically generated.
- * created from	Id: syscalls.master,v 1.11 1998/06/09 03:28:14 bde Exp 
+ * created from	Id: syscalls.master,v 1.12 1998/07/10 22:30:08 jkh Exp 
  */
 
 #define	LINUX_SYS_linux_setup	0
diff --git a/sys/i386/linux/linux_sysent.c b/sys/i386/linux/linux_sysent.c
index da9ac246a517..709fffb6d032 100644
--- a/sys/i386/linux/linux_sysent.c
+++ b/sys/i386/linux/linux_sysent.c
@@ -2,7 +2,7 @@
  * System call switch table.
  *
  * DO NOT EDIT-- this file is automatically generated.
- * created from	Id: syscalls.master,v 1.11 1998/06/09 03:28:14 bde Exp 
+ * created from	Id: syscalls.master,v 1.12 1998/07/10 22:30:08 jkh Exp 
  */
 
 #include "opt_compat.h"
@@ -134,7 +134,7 @@ struct sysent linux_sysent[] = {
 	{ 5, (sy_call_t *)linux_ipc },			/* 117 = linux_ipc */
 	{ 1, (sy_call_t *)fsync },			/* 118 = fsync */
 	{ 1, (sy_call_t *)linux_sigreturn },		/* 119 = linux_sigreturn */
-	{ 0, (sy_call_t *)linux_clone },		/* 120 = linux_clone */
+	{ 2, (sy_call_t *)linux_clone },		/* 120 = linux_clone */
 	{ 2, (sy_call_t *)setdomainname },		/* 121 = setdomainname */
 	{ 1, (sy_call_t *)linux_newuname },		/* 122 = linux_newuname */
 	{ 3, (sy_call_t *)linux_modify_ldt },		/* 123 = linux_modify_ldt */
diff --git a/sys/i386/linux/linux_sysvec.c b/sys/i386/linux/linux_sysvec.c
index 188e3d5a5b69..b8639516ef86 100644
--- a/sys/i386/linux/linux_sysvec.c
+++ b/sys/i386/linux/linux_sysvec.c
@@ -25,7 +25,7 @@
  * (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: linux_sysvec.c,v 1.39 1998/12/14 18:54:01 dt Exp $
+ *  $Id: linux_sysvec.c,v 1.40 1998/12/16 16:28:57 bde Exp $
  */
 
 /* XXX we use functions that might not exist. */
@@ -50,6 +50,10 @@
 #include <vm/vm_prot.h>
 #include <vm/vm_page.h>
 #include <vm/vm_extern.h>
+#ifdef COMPAT_LINUX_THREADS
+#include <sys/lock.h>             /* needed, for now, by vm_map.h */
+#include <vm/vm_map.h>            /* needed, for now, for VM_STACK defines */
+#endif /* COMPAT_LINUX_THREADS */
 #include <sys/exec.h>
 #include <sys/kernel.h>
 #include <sys/module.h>
@@ -217,7 +221,24 @@ linux_sendsig(sig_t catcher, int sig, int mask, u_long code)
 	 *	and the stack can not be grown. useracc will return FALSE
 	 *	if access is denied.
 	 */
+#ifdef COMPAT_LINUX_THREADS
+#ifdef USE_VM_STACK
+#ifndef USE_VM_STACK_FOR_EXEC
+	if ((((caddr_t)fp > p->p_vmspace->vm_maxsaddr &&
+	      (caddr_t)fp < (caddr_t)USRSTACK &&
+	      grow(p, (int)fp) == FALSE) ||
+	     (((caddr_t)fp <= p->p_vmspace->vm_maxsaddr ||
+	       (caddr_t)fp >= (caddr_t)USRSTACK) &&
+	      grow_stack (p, (int)fp) == FALSE)) ||
+#else
+	if ((grow_stack (p, (int)fp) == FALSE) ||
+#endif
+#else
+#endif /* COMPAT_LINUX_THREADS */
 	if ((grow(p, (int)fp) == FALSE) ||
+#ifdef COMPAT_LINUX_THREADS
+#endif
+#endif /* COMPAT_LINUX_THREADS */
 	    (useracc((caddr_t)fp, sizeof (struct linux_sigframe), B_WRITE) == FALSE)) {
 		/*
 		 * Process has trashed its stack; give it an illegal
diff --git a/sys/i386/linux/syscalls.master b/sys/i386/linux/syscalls.master
index 912cb3244597..3b24f1384627 100644
--- a/sys/i386/linux/syscalls.master
+++ b/sys/i386/linux/syscalls.master
@@ -1,4 +1,4 @@
-	$Id: syscalls.master,v 1.11 1998/06/09 03:28:14 bde Exp $
+	$Id: syscalls.master,v 1.12 1998/07/10 22:30:08 jkh Exp $
 
 ;	@(#)syscalls.master	8.1 (Berkeley) 7/19/93
 ; System call name/number master file (or rather, slave, from LINUX).
@@ -171,7 +171,7 @@
 			    caddr_t ptr); }
 118	NOPROTO	LINUX	{ int fsync(int fd); }
 119	STD	LINUX	{ int linux_sigreturn(struct linux_sigcontext *scp); }
-120	STD	LINUX	{ int linux_clone(void); }
+120	STD	LINUX	{ int linux_clone(int flags, void *stack); }
 121	NOPROTO	LINUX	{ int setdomainname(char *name, \
 			    int len); }
 122	STD	LINUX	{ int linux_newuname(struct linux_newuname_t *buf); }
diff --git a/sys/kern/imgact_elf.c b/sys/kern/imgact_elf.c
index 25b7031fe03d..a0a228466784 100644
--- a/sys/kern/imgact_elf.c
+++ b/sys/kern/imgact_elf.c
@@ -26,7 +26,7 @@
  * (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: imgact_elf.c,v 1.42 1998/10/25 17:44:50 phk Exp $
+ *	$Id: imgact_elf.c,v 1.43 1998/12/04 22:54:51 archie Exp $
  */
 
 #include "opt_rlimit.h"
@@ -854,7 +854,11 @@ elf_corehdr(p, vp, cred, numsegs, hdr, hdrsize)
 	status.pr_gregsetsz = sizeof(gregset_t);
 	status.pr_fpregsetsz = sizeof(fpregset_t);
 	status.pr_osreldate = osreldate;
+#ifndef COMPAT_LINUX_THREADS
 	status.pr_cursig = p->p_sigacts->ps_sig;
+#else
+	status.pr_cursig = p->p_sig;
+#endif /* COMPAT_LINUX_THREADS */
 	status.pr_pid = p->p_pid;
 	fill_regs(p, &status.pr_reg);
 
diff --git a/sys/kern/init_main.c b/sys/kern/init_main.c
index fffe109924d8..ae0ad3361b1d 100644
--- a/sys/kern/init_main.c
+++ b/sys/kern/init_main.c
@@ -39,7 +39,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)init_main.c	8.9 (Berkeley) 1/21/94
- * $Id: init_main.c,v 1.98 1998/10/09 23:42:47 peter Exp $
+ * $Id: init_main.c,v 1.99 1998/10/15 17:09:19 peter Exp $
  */
 
 #include "opt_devfs.h"
@@ -83,6 +83,9 @@ static struct session session0;
 static struct pgrp pgrp0;
 struct	proc proc0;
 static struct pcred cred0;
+#ifdef COMPAT_LINUX_THREADS
+static struct procsig procsig0;
+#endif /* COMPAT_LINUX_THREADS */
 static struct filedesc0 filedesc0;
 static struct plimit limit0;
 static struct vmspace vmspace0;
@@ -415,6 +418,12 @@ proc0_init(dummy)
 	p->p_ucred = crget();
 	p->p_ucred->cr_ngroups = 1;	/* group 0 */
 
+#ifdef COMPAT_LINUX_THREADS
+	/* Create procsig. */
+	p->p_procsig = &procsig0;
+	p->p_procsig->ps_refcnt = 2;
+
+#endif /* COMPAT_LINUX_THREADS */
 	/* Create the file descriptor table. */
 	fdp = &filedesc0;
 	p->p_fd = &fdp->fd_fd;
@@ -461,11 +470,20 @@ proc0_init(dummy)
 #endif
 
 	/*
+#ifndef COMPAT_LINUX_THREADS
 	 * We continue to place resource usage info and signal
 	 * actions in the user struct so they're pageable.
 	 */
 	p->p_stats = &p->p_addr->u_stats;
 	p->p_sigacts = &p->p_addr->u_sigacts;
+#else
+	 * We continue to place resource usage info in the user struct so
+	 * it's pageable.
+	 */
+	p->p_stats = &p->p_addr->u_stats;
+
+	p->p_sigacts = &p->p_procsig->ps_sigacts;
+#endif /* COMPAT_LINUX_THREADS */
 
 	/*
 	 * Charge root for one process.
diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c
index fd5e23ef7189..7de0c480ebc7 100644
--- a/sys/kern/kern_exit.c
+++ b/sys/kern/kern_exit.c
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)kern_exit.c	8.7 (Berkeley) 2/12/94
- * $Id: kern_exit.c,v 1.68 1998/11/10 09:16:29 peter Exp $
+ * $Id: kern_exit.c,v 1.69 1998/11/11 10:03:54 truckman Exp $
  */
 
 #include "opt_compat.h"
@@ -181,7 +181,9 @@ exit1(p, rv)
 	 */
 	p->p_flag &= ~(P_TRACED | P_PPWAIT);
 	p->p_flag |= P_WEXIT;
+#ifndef COMPAT_LINUX_THREADS
 	p->p_sigignore = ~0;
+#endif /* COMPAT_LINUX_THREADS */
 	p->p_siglist = 0;
 	if (timevalisset(&p->p_realtimer.it_value))
 		untimeout(realitexpire, (caddr_t)p, p->p_ithandle);
@@ -282,6 +284,9 @@ exit1(p, rv)
 		LIST_REMOVE(q, p_sibling);
 		LIST_INSERT_HEAD(&initproc->p_children, q, p_sibling);
 		q->p_pptr = initproc;
+#ifdef COMPAT_LINUX_THREADS
+		q->p_sigparent = 0;
+#endif /* COMPAT_LINUX_THREADS */
 		/*
 		 * Traced processes are killed
 		 * since their existence means someone is screwing up.
@@ -306,7 +311,11 @@ exit1(p, rv)
 	 * flag set, notify process 1 instead (and hope it will handle
 	 * this situation).
 	 */
+#ifndef COMPAT_LINUX_THREADS
 	if (p->p_pptr->p_flag & P_NOCLDWAIT) {
+#else
+	if (p->p_pptr->p_procsig->ps_flag & P_NOCLDWAIT) {
+#endif /* COMPAT_LINUX_THREADS */
 		struct proc *pp = p->p_pptr;
 		proc_reparent(p, initproc);
 		/*
@@ -318,7 +327,15 @@ exit1(p, rv)
 			wakeup((caddr_t)pp);
 	}
 
+#ifndef COMPAT_LINUX_THREADS
 	psignal(p->p_pptr, SIGCHLD);
+#else
+	if (p->p_sigparent && p->p_pptr != initproc) {
+	        psignal(p->p_pptr, p->p_sigparent);
+	} else {
+	        psignal(p->p_pptr, SIGCHLD);
+	}
+#endif /* COMPAT_LINUX_THREADS */
 	wakeup((caddr_t)p->p_pptr);
 #if defined(tahoe)
 	/* move this to cpu_exit */
@@ -421,6 +438,14 @@ loop:
 		if (uap->pid != WAIT_ANY &&
 		    p->p_pid != uap->pid && p->p_pgid != -uap->pid)
 			continue;
+#ifdef COMPAT_LINUX_THREADS
+		#if 0
+		if ((p->p_sigparent != 0) ^ ((uap->options & WLINUXCLONE) != 0)) {
+			continue;
+		}
+		#endif
+
+#endif /* COMPAT_LINUX_THREADS */
 		nfound++;
 		if (p->p_stat == SZOMB) {
 			/* charge childs scheduling cpu usage to parent */
@@ -488,6 +513,14 @@ loop:
 			LIST_REMOVE(p, p_list);	/* off zombproc */
 			LIST_REMOVE(p, p_sibling);
 
+#ifdef COMPAT_LINUX_THREADS
+			if (--p->p_procsig->ps_refcnt == 0) {
+			        free(p->p_procsig, M_TEMP);
+				p->p_procsig = NULL;
+				p->p_sigacts = NULL;
+			}
+
+#endif /* COMPAT_LINUX_THREADS */
 			/*
 			 * Give machine-dependent layer a chance
 			 * to free anything that cpu_exit couldn't
@@ -543,6 +576,11 @@ proc_reparent(child, parent)
 	LIST_REMOVE(child, p_sibling);
 	LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
 	child->p_pptr = parent;
+#ifdef COMPAT_LINUX_THREADS
+	#if 0
+	child->p_sigparent = 0;
+	#endif
+#endif /* COMPAT_LINUX_THREADS */
 }
 
 /*
diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index a1f6c859fe89..ef38e011908e 100644
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)kern_fork.c	8.6 (Berkeley) 4/8/94
- * $Id: kern_fork.c,v 1.51 1998/01/22 17:29:46 dyson Exp $
+ * $Id: kern_fork.c,v 1.52 1998/11/09 15:07:41 truckman Exp $
  */
 
 #include "opt_ktrace.h"
@@ -62,6 +62,10 @@
 #include <vm/vm_extern.h>
 #include <vm/vm_zone.h>
 
+#ifdef COMPAT_LINUX_THREADS
+#include <machine/frame.h>
+
+#endif /* COMPAT_LINUX_THREADS */
 #ifdef SMP
 static int	fast_vfork = 0;	/* Doesn't work on SMP yet. */
 #else
@@ -325,6 +329,24 @@ again:
 	p2->p_cred->p_refcnt = 1;
 	crhold(p1->p_ucred);
 
+#ifdef COMPAT_LINUX_THREADS
+	if (flags & RFSIGSHARE) {
+		p2->p_procsig->ps_refcnt++;
+	} else {
+		p2->p_procsig = malloc(sizeof(struct procsig), M_TEMP, M_WAITOK);
+		p2->p_procsig->ps_refcnt = 1;
+		p2->p_procsig->ps_posix  = 0;
+		bcopy(&p1->p_procsig->ps_begincopy, &p2->p_procsig->ps_begincopy,
+			(unsigned)&p1->p_procsig->ps_endcopy -
+			(unsigned)&p1->p_procsig->ps_begincopy);
+	}
+	if (flags & RFLINUXTHPN) {
+	        p2->p_sigparent = SIGUSR1;
+	}
+	p2->p_sigacts = &p2->p_procsig->ps_sigacts;
+	if((flags & RFTHREAD) != 0 && (flags & RFPOSIXSIG) != 0)
+	        p2->p_procsig->ps_posix = 1;
+#endif /* COMPAT_LINUX_THREADS */
 	/* bump references to the text vnode (for procfs) */
 	p2->p_textvp = p1->p_textvp;
 	if (p2->p_textvp)
diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index 41b4e0918866..dd4a4318ae3d 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)kern_sig.c	8.7 (Berkeley) 4/18/94
- * $Id: kern_sig.c,v 1.49 1998/11/11 10:03:55 truckman Exp $
+ * $Id: kern_sig.c,v 1.50 1998/12/02 01:53:48 eivind Exp $
  */
 
 #include "opt_compat.h"
@@ -135,9 +135,17 @@ sigaction(p, uap)
 			sa->sa_flags |= SA_RESETHAND;
 		if ((ps->ps_signodefer & bit) != 0)
 			sa->sa_flags |= SA_NODEFER;
+#ifndef COMPAT_LINUX_THREADS
 		if (signum == SIGCHLD && p->p_flag & P_NOCLDSTOP)
+#else
+		if (signum == SIGCHLD && p->p_procsig->ps_flag & P_NOCLDSTOP)
+#endif /* COMPAT_LINUX_THREADS */
 			sa->sa_flags |= SA_NOCLDSTOP;
+#ifndef COMPAT_LINUX_THREADS
 		if (signum == SIGCHLD && p->p_flag & P_NOCLDWAIT)
+#else
+		if (signum == SIGCHLD && p->p_procsig->ps_flag & P_NOCLDWAIT)
+#endif /* COMPAT_LINUX_THREADS */
 			sa->sa_flags |= SA_NOCLDWAIT;
 		if ((error = copyout((caddr_t)sa, (caddr_t)uap->osa,
 		    sizeof (vec))))
@@ -195,9 +203,15 @@ setsigvec(p, signum, sa)
 #endif
 	if (signum == SIGCHLD) {
 		if (sa->sa_flags & SA_NOCLDSTOP)
+#ifndef COMPAT_LINUX_THREADS
 			p->p_flag |= P_NOCLDSTOP;
 		else
 			p->p_flag &= ~P_NOCLDSTOP;
+#else
+			p->p_procsig->ps_flag |= P_NOCLDSTOP;
+		else
+			p->p_procsig->ps_flag &= ~P_NOCLDSTOP;
+#endif /* COMPAT_LINUX_THREADS */
 		if (sa->sa_flags & SA_NOCLDWAIT) {
 			/*
 			 * Paranoia: since SA_NOCLDWAIT is implemented by
@@ -206,11 +220,21 @@ setsigvec(p, signum, sa)
 			 * forbidden to set SA_NOCLDWAIT.
 			 */
 			if (p->p_pid == 1)
+#ifndef COMPAT_LINUX_THREADS
 				p->p_flag &= ~P_NOCLDWAIT;
 			else
 				p->p_flag |= P_NOCLDWAIT;
+#else
+				p->p_procsig->ps_flag &= ~P_NOCLDWAIT;
+			else
+				p->p_procsig->ps_flag |= P_NOCLDWAIT;
+#endif /* COMPAT_LINUX_THREADS */
 		} else
+#ifndef COMPAT_LINUX_THREADS
 			p->p_flag &= ~P_NOCLDWAIT;
+#else
+			p->p_procsig->ps_flag &= ~P_NOCLDWAIT;
+#endif /* COMPAT_LINUX_THREADS */
 	}
 	/*
 	 * Set bit in p_sigignore for signals that are set to SIG_IGN,
@@ -385,7 +409,11 @@ osigvec(p, uap)
 		if ((ps->ps_signodefer & bit) != 0)
 			sv->sv_flags |= SV_NODEFER;
 #ifndef COMPAT_SUNOS
+#ifndef COMPAT_LINUX_THREADS
 		if (signum == SIGCHLD && p->p_flag & P_NOCLDSTOP)
+#else
+		if (signum == SIGCHLD && p->p_procsig->ps_flag & P_NOCLDSTOP)
+#endif /* COMPAT_LINUX_THREADS */
 			sv->sv_flags |= SV_NOCLDSTOP;
 #endif
 		if ((error = copyout((caddr_t)sv, (caddr_t)uap->osv,
@@ -470,8 +498,12 @@ sigsuspend(p, uap)
 	 * save it here and mark the sigacts structure
 	 * to indicate this.
 	 */
+#ifndef COMPAT_LINUX_THREADS
 	ps->ps_oldmask = p->p_sigmask;
 	ps->ps_flags |= SAS_OLDMASK;
+#else
+	p->p_oldsigmask = p->p_sigmask;
+#endif /* COMPAT_LINUX_THREADS */
 	p->p_sigmask = uap->mask &~ sigcantmask;
 	while (tsleep((caddr_t) ps, PPAUSE|PCATCH, "pause", 0) == 0)
 		/* void */;
@@ -730,8 +762,13 @@ trapsignal(p, signum, code)
 			ps->ps_sigact[signum] = SIG_DFL;
 		}
 	} else {
+#ifndef COMPAT_LINUX_THREADS
 		ps->ps_code = code;	/* XXX for core dump/debugger */
 		ps->ps_sig = signum;	/* XXX to verify code */
+#else
+		p->p_code = code;	/* XXX for core dump/debugger */
+		p->p_sig = signum;	/* XXX to verify code */
+#endif /* COMPAT_LINUX_THREADS */
 		psignal(p, signum);
 	}
 }
@@ -780,7 +817,11 @@ psignal(p, signum)
 		 * and if it is set to SIG_IGN,
 		 * action will be SIG_DFL here.)
 		 */
+#ifndef COMPAT_LINUX_THREADS
 		if (p->p_sigignore & mask)
+#else
+		if ((p->p_sigignore & mask) || (p->p_flag & P_WEXIT))
+#endif /* COMPAT_LINUX_THREADS */
 			return;
 		if (p->p_sigmask & mask)
 			action = SIG_HOLD;
@@ -862,7 +903,11 @@ psignal(p, signum)
 				goto out;
 			p->p_siglist &= ~mask;
 			p->p_xstat = signum;
+#ifndef COMPAT_LINUX_THREADS
 			if ((p->p_pptr->p_flag & P_NOCLDSTOP) == 0)
+#else
+			if ((p->p_pptr->p_procsig->ps_flag & P_NOCLDSTOP) == 0)
+#endif /* COMPAT_LINUX_THREADS */
 				psignal(p->p_pptr, SIGCHLD);
 			stop(p);
 			goto out;
@@ -1069,7 +1114,11 @@ issignal(p)
 					break;	/* == ignore */
 				p->p_xstat = signum;
 				stop(p);
+#ifndef COMPAT_LINUX_THREADS
 				if ((p->p_pptr->p_flag & P_NOCLDSTOP) == 0)
+#else
+				if ((p->p_pptr->p_procsig->ps_flag & P_NOCLDSTOP) == 0)
+#endif /* COMPAT_LINUX_THREADS */
 					psignal(p->p_pptr, SIGCHLD);
 				mi_switch();
 				break;
@@ -1144,8 +1193,13 @@ postsig(signum)
 #ifdef KTRACE
 	if (KTRPOINT(p, KTR_PSIG))
 		ktrpsig(p->p_tracep,
+#ifndef COMPAT_LINUX_THREADS
 		    signum, action, ps->ps_flags & SAS_OLDMASK ?
 		    ps->ps_oldmask : p->p_sigmask, 0);
+#else
+		    signum, action, p->p_oldsigmask ?
+		    p->p_oldsigmask : p->p_sigmask, 0);
+#endif /* COMPAT_LINUX_THREADS */
 #endif
 	STOPEVENT(p, S_SIG, signum);
 
@@ -1174,9 +1228,15 @@ postsig(signum)
 		 * restored after the signal processing is completed.
 		 */
 		(void) splhigh();
+#ifndef COMPAT_LINUX_THREADS
 		if (ps->ps_flags & SAS_OLDMASK) {
 			returnmask = ps->ps_oldmask;
 			ps->ps_flags &= ~SAS_OLDMASK;
+#else
+		if (p->p_oldsigmask) {
+			returnmask = p->p_oldsigmask;
+			p->p_oldsigmask = 0;
+#endif /* COMPAT_LINUX_THREADS */
 		} else
 			returnmask = p->p_sigmask;
 		p->p_sigmask |= ps->ps_catchmask[signum] |
@@ -1192,12 +1252,22 @@ postsig(signum)
 		}
 		(void) spl0();
 		p->p_stats->p_ru.ru_nsignals++;
+#ifndef COMPAT_LINUX_THREADS
 		if (ps->ps_sig != signum) {
+#else
+		if (p->p_sig != signum) {
+#endif /* COMPAT_LINUX_THREADS */
 			code = 0;
 		} else {
+#ifndef COMPAT_LINUX_THREADS
 			code = ps->ps_code;
 			ps->ps_code = 0;
 			ps->ps_sig = 0;
+#else
+			code = p->p_code;
+			p->p_code = 0;
+			p->p_sig = 0;
+#endif /* COMPAT_LINUX_THREADS */
 		}
 		(*p->p_sysent->sv_sendsig)(action, signum, returnmask, code);
 	}
@@ -1232,7 +1302,11 @@ sigexit(p, signum)
 
 	p->p_acflag |= AXSIG;
 	if (sigprop[signum] & SA_CORE) {
+#ifndef COMPAT_LINUX_THREADS
 		p->p_sigacts->ps_sig = signum;
+#else
+		p->p_sig = signum;
+#endif /* COMPAT_LINUX_THREADS */
 		/*
 		 * Log signals which would cause core dumps
 		 * (Log as LOG_INFO to appease those who don't want
diff --git a/sys/sys/proc.h b/sys/sys/proc.h
index 7ee6020b0000..d4fd1e2403e2 100644
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)proc.h	8.15 (Berkeley) 5/19/95
- * $Id: proc.h,v 1.61 1998/11/11 10:56:05 truckman Exp $
+ * $Id: proc.h,v 1.62 1998/11/13 17:53:55 dg Exp $
  */
 
 #ifndef _SYS_PROC_H_
@@ -47,6 +47,9 @@
 #include <sys/rtprio.h>			/* For struct rtprio. */
 #include <sys/select.h>			/* For struct selinfo. */
 #include <sys/signal.h>
+#ifdef COMPAT_LINUX_THREADS
+#include <sys/signalvar.h>
+#endif /* COMPAT_LINUX_THREADS */
 #ifndef KERNEL
 #include <sys/time.h>			/* For structs itimerval, timeval. */
 #endif
@@ -78,6 +81,19 @@ struct	pgrp {
 	int	pg_jobc;	/* # procs qualifying pgrp for job control */
 };
 
+#ifdef COMPAT_LINUX_THREADS
+struct	procsig {
+#define ps_begincopy ps_sigignore
+	sigset_t ps_sigignore;	/* Signals being ignored. */
+	sigset_t ps_sigcatch;	/* Signals being caught by user. */
+        int      ps_flag;
+	struct	 sigacts ps_sigacts;
+#define ps_endcopy ps_refcnt
+	int	 ps_refcnt;
+        int      ps_posix;
+};
+
+#endif /* COMPAT_LINUX_THREADS */
 /*
  * Description of a process.
  *
@@ -164,17 +180,34 @@ struct	proc {
 	char	p_pad3[2];		/* padding for alignment */
 	register_t p_retval[2];		/* syscall aux returns */
 	struct	sigiolst p_sigiolst;	/* list of sigio sources */
+#ifdef COMPAT_LINUX_THREADS
+	int	p_sigparent;		/* signal to parent on exit */
+	sigset_t p_oldsigmask;		/* saved mask from before sigpause */
+	int	p_sig;			/* for core dump/debugger XXX */
+        u_long	p_code;	  	        /* for core dump/debugger XXX */
+#endif /* COMPAT_LINUX_THREADS */
 
 /* End area that is zeroed on creation. */
 #define	p_endzero	p_startcopy
 
 /* The following fields are all copied upon creation in fork. */
+#ifndef COMPAT_LINUX_THREADS
 #define	p_startcopy	p_sigmask
-
+#else
+#define	p_startcopy	p_procsig
+#endif /* COMPAT_LINUX_THREADS */
+
+#ifdef COMPAT_LINUX_THREADS
+	struct	procsig *p_procsig;
+#define p_sigignore p_procsig->ps_sigignore
+#define p_sigcatch p_procsig->ps_sigcatch
+#endif /* COMPAT_LINUX_THREADS */
 	sigset_t p_sigmask;	/* Current signal mask. */
+#ifndef COMPAT_LINUX_THREADS
 	sigset_t p_sigignore;	/* Signals being ignored. */
 	sigset_t p_sigcatch;	/* Signals being caught by user. */
 
+#endif /* COMPAT_LINUX_THREADS */
 	u_char	p_priority;	/* Process priority. */
 	u_char	p_usrpri;	/* User-priority based on p_cpu and p_nice. */
 	char	p_nice;		/* Process "nice" value. */
@@ -349,7 +382,11 @@ void	wakeup_one __P((void *chan));
 void	cpu_exit __P((struct proc *)) __dead2;
 void	exit1 __P((struct proc *, int)) __dead2;
 void	cpu_fork __P((struct proc *, struct proc *));
+#ifndef COMPAT_LINUX_THREADS
 int		fork1 __P((struct proc *, int));
+#else
+int	fork1 __P((struct proc *, int));
+#endif /* COMPAT_LINUX_THREADS */
 int	trace_req __P((struct proc *));
 void	cpu_wait __P((struct proc *));
 int	cpu_coredump __P((struct proc *, struct vnode *, struct ucred *));
diff --git a/sys/sys/signalvar.h b/sys/sys/signalvar.h
index 1ca6bedb2e76..a97f950b5477 100644
--- a/sys/sys/signalvar.h
+++ b/sys/sys/signalvar.h
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)signalvar.h	8.6 (Berkeley) 2/19/95
- * $Id: signalvar.h,v 1.19 1998/09/14 05:36:51 jdp Exp $
+ * $Id: signalvar.h,v 1.20 1998/11/11 10:04:13 truckman Exp $
  */
 
 #ifndef	_SYS_SIGNALVAR_H_		/* tmp for user.h */
@@ -55,11 +55,15 @@ struct	sigacts {
 	sigset_t ps_sigintr;		/* signals that interrupt syscalls */
 	sigset_t ps_sigreset;		/* signals that reset when caught */
 	sigset_t ps_signodefer;		/* signals not masked while handled */
+#ifndef COMPAT_LINUX_THREADS
 	sigset_t ps_oldmask;		/* saved mask from before sigpause */
+#endif /* COMPAT_LINUX_THREADS */
 	int	ps_flags;		/* signal flags, below */
 	struct	sigaltstack ps_sigstk;	/* sp & on stack state variable */
+#ifndef COMPAT_LINUX_THREADS
 	int	ps_sig;			/* for core dump/debugger XXX */
 	u_long	ps_code;		/* for core dump/debugger XXX */
+#endif /* COMPAT_LINUX_THREADS */
 	sigset_t ps_usertramp;		/* SunOS compat; libc sigtramp XXX */
 };
 
diff --git a/sys/sys/unistd.h b/sys/sys/unistd.h
index b96572d6f8e1..17b2028a99a4 100644
--- a/sys/sys/unistd.h
+++ b/sys/sys/unistd.h
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)unistd.h	8.2 (Berkeley) 1/7/94
- * $Id: unistd.h,v 1.16 1998/03/08 17:25:38 dufault Exp $
+ * $Id: unistd.h,v 1.17 1998/03/28 11:51:01 dufault Exp $
  */
 
 #ifndef _SYS_UNISTD_H_
@@ -186,6 +186,9 @@
 #define RFCENVG		(1<<11) /* UNIMPL zero plan9 `env space' */
 #define RFCFDG		(1<<12) /* zero fd table */
 #define RFTHREAD	(1<<13)	/* enable kernel thread support */
+#define RFSIGSHARE	(1<<14)	/* share signal handlers */
+#define RFPOSIXSIG      (1<<15) /* UNIMPL posix thread signal delivery */
+#define RFLINUXTHPN     (1<<16) /* do linux clone exit parent notification */
 #define RFPPWAIT	(1<<31) /* parent sleeps until child exits (vfork) */
 
 #endif /* !_POSIX_SOURCE */
diff --git a/sys/sys/user.h b/sys/sys/user.h
index 9a34940977b2..f97891cbfb2a 100644
--- a/sys/sys/user.h
+++ b/sys/sys/user.h
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)user.h	8.2 (Berkeley) 9/23/93
- * $Id: user.h,v 1.15 1998/03/28 10:33:24 bde Exp $
+ * $Id: user.h,v 1.16 1998/07/15 20:18:00 dfr Exp $
  */
 
 #ifndef _SYS_USER_H_
@@ -102,7 +102,9 @@ void fill_eproc __P((struct proc *, struct eproc *));
 struct	user {
 	struct	pcb u_pcb;
 
+#ifndef COMPAT_LINUX_THREADS
 	struct	sigacts u_sigacts;	/* p_sigacts points here (use it!) */
+#endif /* COMPAT_LINUX_THREADS */
 	struct	pstats u_stats;		/* p_stats points here (use it!) */
 
 	/*
@@ -127,8 +129,13 @@ struct	user {
 #define	U_tsize	u_kproc.kp_eproc.e_vm.vm_tsize
 #define	U_dsize	u_kproc.kp_eproc.e_vm.vm_dsize
 #define	U_ssize	u_kproc.kp_eproc.e_vm.vm_ssize
+#ifndef COMPAT_LINUX_THREADS
 #define	U_sig	u_sigacts.ps_sig
 #define	U_code	u_sigacts.ps_code
+#else
+#define	U_sig	u_kproc.kp_proc.p_sig
+#define	U_code	u_kproc.kp_proc.p_code
+#endif /* COMPAT_LINUX_THREADS */
 
 #ifndef KERNEL
 #define	u_ar0	U_ar0
diff --git a/sys/vm/vm_glue.c b/sys/vm/vm_glue.c
index e73862d9fa9c..33131499a007 100644
--- a/sys/vm/vm_glue.c
+++ b/sys/vm/vm_glue.c
@@ -59,7 +59,7 @@
  * any improvements or extensions that they make and grant Carnegie the
  * rights to redistribute these changes.
  *
- * $Id: vm_glue.c,v 1.76 1998/09/29 17:33:59 abial Exp $
+ * $Id: vm_glue.c,v 1.77 1998/10/13 08:24:43 dg Exp $
  */
 
 #include "opt_rlimit.h"
@@ -230,13 +230,20 @@ vm_fork(p1, p2, flags)
 	up = p2->p_addr;
 
 	/*
+#ifndef COMPAT_LINUX_THREADS
 	 * p_stats and p_sigacts currently point at fields in the user struct
 	 * but not at &u, instead at p_addr. Copy p_sigacts and parts of
+#else
+	 * p_stats currently points at fields in the user struct
+	 * but not at &u, instead at p_addr. Copy parts of
+#endif /* COMPAT_LINUX_THREADS */
 	 * p_stats; zero the rest of p_stats (statistics).
 	 */
 	p2->p_stats = &up->u_stats;
+#ifndef COMPAT_LINUX_THREADS
 	p2->p_sigacts = &up->u_sigacts;
 	up->u_sigacts = *p1->p_sigacts;
+#endif /* COMPAT_LINUX_THREADS */
 	bzero(&up->u_stats.pstat_startzero,
 	    (unsigned) ((caddr_t) &up->u_stats.pstat_endzero -
 		(caddr_t) &up->u_stats.pstat_startzero));