strace improvement patch

Below is a patch to make "strace -f" work (again) for clone()/clone2() system calls. Most of the patch is from Roland's (?) patch shipped with the strace-4.8-8 RPM (strace-4.4-clone-fixes.patch). The only changes I made are:

* defs.h: declare pid2tcb() to avoid pointer-truncation on 64-bit platforms.
* process.c: define internal_clone() if either SYS_clone or SYS_clone2 is defined.
* util.c (arg_setup) [IA64]: Make it work for syscall-stubs that have a non-empty local register partition.
(set_arg0) [IA64]: Fix it so it actually works.
(set_arg1) [IA64]: Ditto.
(setbpt): Treat SYS_clone2 like SYS_clone.

Also, I'd recommend to use gcc-3.2 for compiling strace. I encountered some strange bugs with gcc-2.96, though I did not try to track them down. With gcc-3.2, those bugs went away and strace now seems to work quite nicely (once again, that is). Oh, I only tested on 2.5.xx, though I think it should work fine on 2.4.xx as well.

Is there any reason not to integrate Roland's patch into strace? IMHO, the new approach of using CLONE_PTRACE to trace clone()/fork() is infinitely better than the old code-patching approach.

	--david

Index: defs.h
=================================RCS file: /cvsroot/strace/strace/defs.h,v retrieving revision 1.34

diff -u -r1.34 defs.h
@@ -371,6 +371,7 @@
 extern int set_personality P((int personality));
 extern char *xlookup P((struct xlat *, int));
 extern struct tcb *alloctcb P((int));
+extern struct tcb *pid2tcb P((int pid));
 extern void droptcb P((struct tcb *));
 
 extern void set_sortby P((char *));

Index: process.c
=================================RCS file: /cvsroot/strace/strace/process.c,v retrieving revision 1.44

Index: strace.c
=================================RCS file: /cvsroot/strace/strace/strace.c,v retrieving revision 1.38

Index: syscall.c
=================================RCS file: /cvsroot/strace/strace/syscall.c,v retrieving revision 1.43

diff -u -r1.43 syscall.c
@@ -896,16 +896,16 @@
 			if (upeek (pid, PT_R15, &scno) < 0)
 				return -1;
 		}
+		if (tcp->flags & TCB_WAITEXECVE) {
+			tcp->flags &= ~TCB_WAITEXECVE;
+			return 0;
+		}
 	} else {
 		/* syscall in progress */
 		if (upeek (pid, PT_R8, &r8) < 0)
 			return -1;
 		if (upeek (pid, PT_R10, &r10) < 0)
 			return -1;
-	}
-	if (tcp->flags & TCB_WAITEXECVE) {
-		tcp->flags &= ~TCB_WAITEXECVE;
-		return 0;
 	}
 
 #elif defined (ARM)

Index: util.c
=================================RCS file: /cvsroot/strace/strace/util.c,v retrieving revision 1.31