PATCH: ptrace support for fork/vfork/clone events [1/3]

PATCH: ptrace support for fork/vfork/clone events [1/3]

[Daniel Jacobowitz]

I think I've answered everyone's concerns about these patches (again). 
Yet another Debian user asked me about their status last night, so I'm
going to submit them again.  I'm actively using the 2.4 backport, and I
find it invaluable when debugging multi-process problems.

These three patches provide an event-mask interface for ptrace clients to   
watch for events in debugged processes.  The supported events right now are
fork, vfork, clone, and execve.  This interface only triggers on the
requested events, which makes it a great deal more practical than using
PTRACE_SYSCALL.

Why is this necessary?  Without it, there are some things GDB can't do.  You
can't step over a call to fork(), because when you do, the child process 
will hit the parent's step breakpoint and exit with SIGTRAP.  You also can't
choose to debug the child instead of the parent, because GDB doesn't have a
chance to attach to it before it continues or exits.

There's no other viable way to do this without kernel support; using a
trampoline is racy (as well as exceedingly complicated from a lightweight
debugger standpoint).

The code is in three parts:
 1. Factor out some common ptrace code; implement PTRACE_O_TRACESYSGOOD
    and PTRACE_SETOPTIONS for every architecture.  This one will let me unify
    a great deal more of the architecture ptrace implementations later.      
 2. Add a new clone flag, CLONE_UNTRACED, and force it in all kernel_thread 
    implementations.  Needed by the next patch.  This one touches every
    architecture and some of them in assembly; I've tried to get them all   
    correct.
    [Why is this needed?  It's needed so that the debugger doesn't get
    triggered on, say, a kernel-started modprobe process or some other
    kernel thread.  That'd confuse the debugger, beyond the other possible  
    security/stability problems.]
 3. Add PTRACE_GETEVENTMSG and four new flags to PTRACE_SETOPTIONS, to allow
    tracing fork, vfork, clone, and exec events.

The patches have been tested on i386, and a 2.4 backport tested on SH, MIPS,
i386, PowerPC, and ARM; I have GDB using this mechanism and have run that
through more stress tests than I really want to remember right now.

Future plans for the unified ptrace handling include READDATA/WRITEDATA for
all architectures (someone else submitted code to do this just recently for
2.4, but mine's a little cleaner, I think) and page-protection based
watchpoints for targets which don't have available hardware watchpoints
(thanks to Klee at Apple for enlightening me on this concept :).
                                                                
The three patches are available at:
  http://crack.them.org/~drow/forks/

or from the BK tree at:
  bk://nevyn.them.org:5000

Here's #1.

# This is a BitKeeper generated patch for the following project:
# Project Name: Linux kernel tree
# This patch format is intended for GNU patch command version 2.5 or higher.
# This patch includes the following deltas:
#	           ChangeSet	1.855   -> 1.856  
#	include/asm-i386/ptrace.h	1.2.1.1 -> 1.4    
#	arch/s390x/kernel/ptrace.c	1.7.1.1 -> 1.9    
#	include/linux/ptrace.h	1.3     -> 1.4    
#	arch/arm/kernel/ptrace.c	1.12.1.2 -> 1.14   
#	arch/sh/kernel/ptrace.c	1.7     -> 1.8    
#	arch/parisc/kernel/ptrace.c	1.4.1.1 -> 1.6    
#	include/asm-s390x/ptrace.h	1.3.1.1 -> 1.5    
#	arch/mips64/kernel/ptrace.c	1.6     -> 1.7    
#	arch/ppc/kernel/ptrace.c	1.10    -> 1.11   
#	arch/i386/kernel/ptrace.c	1.13.1.1 -> 1.15   
#	arch/x86_64/ia32/ptrace32.c	1.2.1.1 -> 1.4    
#	arch/ppc64/kernel/ptrace.c	1.3.1.1 -> 1.5    
#	arch/m68k/kernel/ptrace.c	1.7     -> 1.8    
#	include/asm-x86_64/ptrace.h	1.3.1.1 -> 1.5    
#	arch/x86_64/kernel/ptrace.c	1.3.1.1 -> 1.5    
#	arch/cris/kernel/ptrace.c	1.8     -> 1.9    
#	arch/ppc64/kernel/ptrace32.c	1.5.1.1 -> 1.7    
#	include/asm-arm/ptrace.h	1.2     -> 1.3    
#	include/asm-mips/ptrace.h	1.2     -> 1.3    
#	arch/ia64/ia32/sys_ia32.c	1.24    -> 1.25   
#	include/asm-ia64/ptrace.h	1.4     -> 1.5    
#	include/asm-s390/ptrace.h	1.5.1.1 -> 1.7    
#	include/asm-sh/ptrace.h	1.2     -> 1.3    
#	arch/alpha/kernel/ptrace.c	1.9     -> 1.10   
#	arch/s390/kernel/ptrace.c	1.8.1.1 -> 1.10   
#	include/asm-mips64/ptrace.h	1.1     -> 1.2    
#	arch/sparc64/kernel/ptrace.c	1.16    -> 1.17   
#	arch/ia64/kernel/ptrace.c	1.11.1.1 -> 1.13   
#	arch/sparc/kernel/ptrace.c	1.11    -> 1.12   
#	arch/mips/kernel/ptrace.c	1.8     -> 1.9    
#	     kernel/ptrace.c	1.18    -> 1.19   
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 02/10/31	drow@nevyn.them.org	1.856
# Merge nevyn.them.org:/nevyn/big/kernel/linux-2.5
# into nevyn.them.org:/nevyn/big/kernel/test/linux-2.5-trace1
# --------------------------------------------
#
diff -Nru a/arch/alpha/kernel/ptrace.c b/arch/alpha/kernel/ptrace.c
--- a/arch/alpha/kernel/ptrace.c	Thu Oct 31 14:02:17 2002
+++ b/arch/alpha/kernel/ptrace.c	Thu Oct 31 14:02:17 2002
@@ -383,7 +383,7 @@
 		goto out;
 
 	default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		goto out;
 	}
  out:
@@ -400,7 +400,8 @@
 		return;
 	if (!(current->ptrace & PT_PTRACED))
 		return;
-	current->exit_code = SIGTRAP;
+	current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
+					? 0x80 : 0);
 	current->state = TASK_STOPPED;
 	notify_parent(current, SIGCHLD);
 	schedule();
diff -Nru a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c
--- a/arch/arm/kernel/ptrace.c	Thu Oct 31 14:02:16 2002
+++ b/arch/arm/kernel/ptrace.c	Thu Oct 31 14:02:16 2002
@@ -692,16 +692,8 @@
 			ret = ptrace_setfpregs(child, (void *)data);
 			break;
 
-		case PTRACE_SETOPTIONS:
-			if (data & PTRACE_O_TRACESYSGOOD)
-				child->ptrace |= PT_TRACESYSGOOD;
-			else
-				child->ptrace &= ~PT_TRACESYSGOOD;
-			ret = 0;
-			break;
-
 		default:
-			ret = -EIO;
+			ret = ptrace_request(child, request, addr, data);
 			break;
 	}
 
diff -Nru a/arch/cris/kernel/ptrace.c b/arch/cris/kernel/ptrace.c
--- a/arch/cris/kernel/ptrace.c	Thu Oct 31 14:02:16 2002
+++ b/arch/cris/kernel/ptrace.c	Thu Oct 31 14:02:16 2002
@@ -292,7 +292,7 @@
 		}
 
 		default:
-			ret = -EIO;
+			ret = ptrace_request(child, request, addr, data);
 			break;
 	}
 out_tsk:
@@ -307,10 +307,8 @@
 	if ((current->ptrace & (PT_PTRACED | PT_TRACESYS)) !=
 	    (PT_PTRACED | PT_TRACESYS))
 		return;
-	/* TODO: make a way to distinguish between a syscall stop and SIGTRAP
-	 * delivery like in the i386 port ? 
-	 */
-	current->exit_code = SIGTRAP;
+	current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
+					? 0x80 : 0);
 	current->state = TASK_STOPPED;
 	notify_parent(current, SIGCHLD);
 	schedule();
diff -Nru a/arch/i386/kernel/ptrace.c b/arch/i386/kernel/ptrace.c
--- a/arch/i386/kernel/ptrace.c	Thu Oct 31 14:02:16 2002
+++ b/arch/i386/kernel/ptrace.c	Thu Oct 31 14:02:16 2002
@@ -416,17 +416,8 @@
 		break;
 	}
 
-	case PTRACE_SETOPTIONS: {
-		if (data & PTRACE_O_TRACESYSGOOD)
-			child->ptrace |= PT_TRACESYSGOOD;
-		else
-			child->ptrace &= ~PT_TRACESYSGOOD;
-		ret = 0;
-		break;
-	}
-
 	default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		break;
 	}
 out_tsk:
diff -Nru a/arch/ia64/ia32/sys_ia32.c b/arch/ia64/ia32/sys_ia32.c
--- a/arch/ia64/ia32/sys_ia32.c	Thu Oct 31 14:02:17 2002
+++ b/arch/ia64/ia32/sys_ia32.c	Thu Oct 31 14:02:17 2002
@@ -3076,7 +3076,7 @@
 		break;
 
 	      default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		break;
 
 	}
diff -Nru a/arch/ia64/kernel/ptrace.c b/arch/ia64/kernel/ptrace.c
--- a/arch/ia64/kernel/ptrace.c	Thu Oct 31 14:02:17 2002
+++ b/arch/ia64/kernel/ptrace.c	Thu Oct 31 14:02:17 2002
@@ -1268,16 +1268,8 @@
 		ret = ptrace_setregs(child, (struct pt_all_user_regs*) data);
 		goto out_tsk;
 
-	      case PTRACE_SETOPTIONS:
-		if (data & PTRACE_O_TRACESYSGOOD)
-			child->ptrace |= PT_TRACESYSGOOD;
-		else
-			child->ptrace &= ~PT_TRACESYSGOOD;
-		ret = 0;
-		break;
-
 	      default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		goto out_tsk;
 	}
   out_tsk:
diff -Nru a/arch/m68k/kernel/ptrace.c b/arch/m68k/kernel/ptrace.c
--- a/arch/m68k/kernel/ptrace.c	Thu Oct 31 14:02:16 2002
+++ b/arch/m68k/kernel/ptrace.c	Thu Oct 31 14:02:16 2002
@@ -355,7 +355,7 @@
 		}
 
 		default:
-			ret = -EIO;
+			ret = ptrace_request(child, request, addr, data);
 			break;
 	}
 out_tsk:
@@ -370,7 +370,8 @@
 	if (!current->thread.work.delayed_trace &&
 	    !current->thread.work.syscall_trace)
 		return;
-	current->exit_code = SIGTRAP;
+	current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
+					? 0x80 : 0);
 	current->state = TASK_STOPPED;
 	notify_parent(current, SIGCHLD);
 	schedule();
diff -Nru a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
--- a/arch/mips/kernel/ptrace.c	Thu Oct 31 14:02:17 2002
+++ b/arch/mips/kernel/ptrace.c	Thu Oct 31 14:02:17 2002
@@ -304,16 +304,8 @@
 		res = ptrace_detach(child, data);
 		break;
 
-	case PTRACE_SETOPTIONS:
-		if (data & PTRACE_O_TRACESYSGOOD)
-			child->ptrace |= PT_TRACESYSGOOD;
-		else
-			child->ptrace &= ~PT_TRACESYSGOOD;
-		res = 0;
-		break;
-
 	default:
-		res = -EIO;
+		res = ptrace_request(child, request, addr, data);
 		goto out;
 	}
 out_tsk:
diff -Nru a/arch/mips64/kernel/ptrace.c b/arch/mips64/kernel/ptrace.c
--- a/arch/mips64/kernel/ptrace.c	Thu Oct 31 14:02:16 2002
+++ b/arch/mips64/kernel/ptrace.c	Thu Oct 31 14:02:16 2002
@@ -275,17 +275,8 @@
 		ret = ptrace_detach(child, data);
 		break;
 
-	case PTRACE_SETOPTIONS: {
-		if (data & PTRACE_O_TRACESYSGOOD)
-			child->ptrace |= PT_TRACESYSGOOD;
-		else
-			child->ptrace &= ~PT_TRACESYSGOOD;
-		ret = 0;
-		break;
-	}
-
 	default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		break;
 	}
 
@@ -535,17 +526,8 @@
 		ret = ptrace_detach(child, data);
 		break;
 
-	case PTRACE_SETOPTIONS: {
-		if (data & PTRACE_O_TRACESYSGOOD)
-			child->ptrace |= PT_TRACESYSGOOD;
-		else
-			child->ptrace &= ~PT_TRACESYSGOOD;
-		ret = 0;
-		break;
-	}
-
 	default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		break;
 	}
 
diff -Nru a/arch/parisc/kernel/ptrace.c b/arch/parisc/kernel/ptrace.c
--- a/arch/parisc/kernel/ptrace.c	Thu Oct 31 14:02:16 2002
+++ b/arch/parisc/kernel/ptrace.c	Thu Oct 31 14:02:16 2002
@@ -385,7 +385,7 @@
 		goto out_tsk;
 
 	default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		goto out_tsk;
 	}
 
@@ -409,7 +409,8 @@
 		return;
 	if (!(current->ptrace & PT_PTRACED))
 		return;
-	current->exit_code = SIGTRAP;
+	current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
+					? 0x80 : 0);
 	current->state = TASK_STOPPED;
 	notify_parent(current, SIGCHLD);
 	schedule();
diff -Nru a/arch/ppc/kernel/ptrace.c b/arch/ppc/kernel/ptrace.c
--- a/arch/ppc/kernel/ptrace.c	Thu Oct 31 14:02:16 2002
+++ b/arch/ppc/kernel/ptrace.c	Thu Oct 31 14:02:16 2002
@@ -339,7 +339,7 @@
 #endif
 
 	default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		break;
 	}
 out_tsk:
@@ -354,7 +354,8 @@
         if (!test_thread_flag(TIF_SYSCALL_TRACE)
 	    || !(current->ptrace & PT_PTRACED))
 		return;
-	current->exit_code = SIGTRAP;
+	current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
+					? 0x80 : 0);
 	current->state = TASK_STOPPED;
 	notify_parent(current, SIGCHLD);
 	schedule();
diff -Nru a/arch/ppc64/kernel/ptrace.c b/arch/ppc64/kernel/ptrace.c
--- a/arch/ppc64/kernel/ptrace.c	Thu Oct 31 14:02:16 2002
+++ b/arch/ppc64/kernel/ptrace.c	Thu Oct 31 14:02:16 2002
@@ -276,7 +276,7 @@
 	}
 
 	default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		break;
 	}
 out_tsk:
@@ -292,7 +292,8 @@
 		return;
 	if (!(current->ptrace & PT_PTRACED))
 		return;
-	current->exit_code = SIGTRAP;
+	current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
+					? 0x80 : 0);
 	current->state = TASK_STOPPED;
 	notify_parent(current, SIGCHLD);
 	schedule();
diff -Nru a/arch/ppc64/kernel/ptrace32.c b/arch/ppc64/kernel/ptrace32.c
--- a/arch/ppc64/kernel/ptrace32.c	Thu Oct 31 14:02:16 2002
+++ b/arch/ppc64/kernel/ptrace32.c	Thu Oct 31 14:02:16 2002
@@ -413,7 +413,7 @@
 
 
 	default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		break;
 	}
 out_tsk:
diff -Nru a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
--- a/arch/s390/kernel/ptrace.c	Thu Oct 31 14:02:17 2002
+++ b/arch/s390/kernel/ptrace.c	Thu Oct 31 14:02:17 2002
@@ -307,15 +307,8 @@
 			copied += sizeof(unsigned long);
 		}
 		return 0;
-
-	case PTRACE_SETOPTIONS:
-		if (data & PTRACE_O_TRACESYSGOOD)
-			child->ptrace |= PT_TRACESYSGOOD;
-		else
-			child->ptrace &= ~PT_TRACESYSGOOD;
-		return 0;
 	}
-	return -EIO;
+	return ptrace_request(child, request, addr, data);
 }
 
 asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
diff -Nru a/arch/s390x/kernel/ptrace.c b/arch/s390x/kernel/ptrace.c
--- a/arch/s390x/kernel/ptrace.c	Thu Oct 31 14:02:16 2002
+++ b/arch/s390x/kernel/ptrace.c	Thu Oct 31 14:02:16 2002
@@ -261,7 +261,7 @@
 		}
 		return 0;
 	}
-	return -EIO;
+	return ptrace_request(child, request, addr, data);
 }
 
 #ifdef CONFIG_S390_SUPPORT
@@ -469,7 +469,7 @@
 		}
 		return 0;
 	}
-	return -EIO;
+	return ptrace_request(child, request, addr, data);
 }
 #endif
 
@@ -538,12 +538,6 @@
 		/* detach a process that was attached. */
 		return ptrace_detach(child, data);
 
-	case PTRACE_SETOPTIONS:
-		if (data & PTRACE_O_TRACESYSGOOD)
-			child->ptrace |= PT_TRACESYSGOOD;
-		else
-			child->ptrace &= ~PT_TRACESYSGOOD;
-		return 0;
 	/* Do requests that differ for 31/64 bit */
 	default:
 #ifdef CONFIG_S390_SUPPORT
@@ -551,8 +545,8 @@
 			return do_ptrace_emu31(child, request, addr, data);
 #endif
 		return do_ptrace_normal(child, request, addr, data);
-		
 	}
+	/* Not reached.  */
 	return -EIO;
 }
 
diff -Nru a/arch/sh/kernel/ptrace.c b/arch/sh/kernel/ptrace.c
--- a/arch/sh/kernel/ptrace.c	Thu Oct 31 14:02:16 2002
+++ b/arch/sh/kernel/ptrace.c	Thu Oct 31 14:02:16 2002
@@ -356,17 +356,8 @@
 		ret = ptrace_detach(child, data);
 		break;
 
-	case PTRACE_SETOPTIONS: {
-		if (data & PTRACE_O_TRACESYSGOOD)
-			child->ptrace |= PT_TRACESYSGOOD;
-		else
-			child->ptrace &= ~PT_TRACESYSGOOD;
-		ret = 0;
-		break;
-	}
-
 	default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		break;
 	}
 out_tsk:
diff -Nru a/arch/sparc/kernel/ptrace.c b/arch/sparc/kernel/ptrace.c
--- a/arch/sparc/kernel/ptrace.c	Thu Oct 31 14:02:17 2002
+++ b/arch/sparc/kernel/ptrace.c	Thu Oct 31 14:02:17 2002
@@ -584,10 +584,15 @@
 
 	/* PTRACE_DUMPCORE unsupported... */
 
-	default:
-		pt_error_return(regs, EIO);
+	default: {
+		int err = ptrace_request(child, request, addr, data);
+		if (err)
+			pt_error_return(regs, -err);
+		else
+			pt_succ_return(regs, 0);
 		goto out_tsk;
 	}
+	}
 out_tsk:
 	if (child)
 		put_task_struct(child);
@@ -604,7 +609,8 @@
 		return;
 	if (!(current->ptrace & PT_PTRACED))
 		return;
-	current->exit_code = SIGTRAP;
+	current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
+					? 0x80 : 0);
 	current->state = TASK_STOPPED;
 	current->thread.flags ^= MAGIC_CONSTANT;
 	notify_parent(current, SIGCHLD);
diff -Nru a/arch/sparc64/kernel/ptrace.c b/arch/sparc64/kernel/ptrace.c
--- a/arch/sparc64/kernel/ptrace.c	Thu Oct 31 14:02:17 2002
+++ b/arch/sparc64/kernel/ptrace.c	Thu Oct 31 14:02:17 2002
@@ -571,10 +571,15 @@
 
 	/* PTRACE_DUMPCORE unsupported... */
 
-	default:
-		pt_error_return(regs, EIO);
+	default: {
+		int err = ptrace_request(child, request, addr, data);
+		if (err)
+			pt_error_return(regs, -err);
+		else
+			pt_succ_return(regs, 0);
 		goto out_tsk;
 	}
+	}
 flush_and_out:
 	{
 		unsigned long va;
@@ -612,7 +617,8 @@
 		return;
 	if (!(current->ptrace & PT_PTRACED))
 		return;
-	current->exit_code = SIGTRAP;
+	current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
+					? 0x80 : 0);
 	current->state = TASK_STOPPED;
 	notify_parent(current, SIGCHLD);
 	schedule();
diff -Nru a/arch/x86_64/ia32/ptrace32.c b/arch/x86_64/ia32/ptrace32.c
--- a/arch/x86_64/ia32/ptrace32.c	Thu Oct 31 14:02:16 2002
+++ b/arch/x86_64/ia32/ptrace32.c	Thu Oct 31 14:02:16 2002
@@ -185,17 +185,6 @@
 	__u32 val;
 
 	switch (request) { 
-	case PTRACE_TRACEME:
-	case PTRACE_ATTACH:
-	case PTRACE_SYSCALL:
-	case PTRACE_CONT:
-	case PTRACE_KILL:
-	case PTRACE_SINGLESTEP:
-	case PTRACE_DETACH:
-	case PTRACE_SETOPTIONS:
-		ret = sys_ptrace(request, pid, addr, data); 
-		return ret;
-
 	case PTRACE_PEEKTEXT:
 	case PTRACE_PEEKDATA:
 	case PTRACE_POKEDATA:
@@ -211,7 +200,8 @@
 		break;
 		
 	default:
-		return -EIO;
+		ret = sys_ptrace(request, pid, addr, data); 
+		return ret;
 	} 
 
 	child = find_target(request, pid, &ret);
diff -Nru a/arch/x86_64/kernel/ptrace.c b/arch/x86_64/kernel/ptrace.c
--- a/arch/x86_64/kernel/ptrace.c	Thu Oct 31 14:02:16 2002
+++ b/arch/x86_64/kernel/ptrace.c	Thu Oct 31 14:02:16 2002
@@ -405,17 +405,8 @@
 		break;
 	}
 
-	case PTRACE_SETOPTIONS: {
-		if (data & PTRACE_O_TRACESYSGOOD)
-			child->ptrace |= PT_TRACESYSGOOD;
-		else
-			child->ptrace &= ~PT_TRACESYSGOOD;
-		ret = 0;
-		break;
-	}
-
 	default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		break;
 	}
 out_tsk:
diff -Nru a/include/asm-arm/ptrace.h b/include/asm-arm/ptrace.h
--- a/include/asm-arm/ptrace.h	Thu Oct 31 14:02:16 2002
+++ b/include/asm-arm/ptrace.h	Thu Oct 31 14:02:16 2002
@@ -6,10 +6,7 @@
 #define PTRACE_GETFPREGS	14
 #define PTRACE_SETFPREGS	15
 
-#define PTRACE_SETOPTIONS	21
-
-/* options set using PTRACE_SETOPTIONS */
-#define PTRACE_O_TRACESYSGOOD	0x00000001
+#define PTRACE_OLDSETOPTIONS	21
 
 #include <asm/proc/ptrace.h>
 
diff -Nru a/include/asm-i386/ptrace.h b/include/asm-i386/ptrace.h
--- a/include/asm-i386/ptrace.h	Thu Oct 31 14:02:16 2002
+++ b/include/asm-i386/ptrace.h	Thu Oct 31 14:02:16 2002
@@ -49,10 +49,7 @@
 #define PTRACE_GETFPXREGS         18
 #define PTRACE_SETFPXREGS         19
 
-#define PTRACE_SETOPTIONS         21
-
-/* options set using PTRACE_SETOPTIONS */
-#define PTRACE_O_TRACESYSGOOD     0x00000001
+#define PTRACE_OLDSETOPTIONS         21
 
 #ifdef __KERNEL__
 #define user_mode(regs) ((VM_MASK & (regs)->eflags) || (3 & (regs)->xcs))
diff -Nru a/include/asm-ia64/ptrace.h b/include/asm-ia64/ptrace.h
--- a/include/asm-ia64/ptrace.h	Thu Oct 31 14:02:17 2002
+++ b/include/asm-ia64/ptrace.h	Thu Oct 31 14:02:17 2002
@@ -287,9 +287,6 @@
 #define PTRACE_GETREGS		18	/* get all registers (pt_all_user_regs) in one shot */
 #define PTRACE_SETREGS		19	/* set all registers (pt_all_user_regs) in one shot */
 
-#define PTRACE_SETOPTIONS	21
-
-/* options set using PTRACE_SETOPTIONS */
-#define PTRACE_O_TRACESYSGOOD	0x00000001
+#define PTRACE_OLDSETOPTIONS	21
 
 #endif /* _ASM_IA64_PTRACE_H */
diff -Nru a/include/asm-mips/ptrace.h b/include/asm-mips/ptrace.h
--- a/include/asm-mips/ptrace.h	Thu Oct 31 14:02:16 2002
+++ b/include/asm-mips/ptrace.h	Thu Oct 31 14:02:16 2002
@@ -59,10 +59,7 @@
 /* #define PTRACE_GETFPXREGS		18 */
 /* #define PTRACE_SETFPXREGS		19 */
 
-#define PTRACE_SETOPTIONS	21
-
-/* options set using PTRACE_SETOPTIONS */
-#define PTRACE_O_TRACESYSGOOD	0x00000001
+#define PTRACE_OLDSETOPTIONS	21
 
 #ifdef _LANGUAGE_ASSEMBLY
 #include <asm/offset.h>
diff -Nru a/include/asm-mips64/ptrace.h b/include/asm-mips64/ptrace.h
--- a/include/asm-mips64/ptrace.h	Thu Oct 31 14:02:17 2002
+++ b/include/asm-mips64/ptrace.h	Thu Oct 31 14:02:17 2002
@@ -64,10 +64,7 @@
 /* #define PTRACE_GETFPXREGS		18 */
 /* #define PTRACE_SETFPXREGS		19 */
 
-#define PTRACE_SETOPTIONS	21
-
-/* options set using PTRACE_SETOPTIONS */
-#define PTRACE_O_TRACESYSGOOD	0x00000001
+#define PTRACE_OLDSETOPTIONS	21
 
 #ifdef _LANGUAGE_ASSEMBLY
 #include <asm/offset.h>
diff -Nru a/include/asm-s390/ptrace.h b/include/asm-s390/ptrace.h
--- a/include/asm-s390/ptrace.h	Thu Oct 31 14:02:17 2002
+++ b/include/asm-s390/ptrace.h	Thu Oct 31 14:02:17 2002
@@ -105,10 +105,7 @@
 
 #define STACK_FRAME_OVERHEAD	96	/* size of minimum stack frame */
 
-#define PTRACE_SETOPTIONS         21
-
-/* options set using PTRACE_SETOPTIONS */
-#define PTRACE_O_TRACESYSGOOD     0x00000001
+#define PTRACE_OLDSETOPTIONS         21
 
 #ifndef __ASSEMBLY__
 #include <linux/config.h>
diff -Nru a/include/asm-s390x/ptrace.h b/include/asm-s390x/ptrace.h
--- a/include/asm-s390x/ptrace.h	Thu Oct 31 14:02:16 2002
+++ b/include/asm-s390x/ptrace.h	Thu Oct 31 14:02:16 2002
@@ -85,10 +85,7 @@
 
 #define STACK_FRAME_OVERHEAD    160      /* size of minimum stack frame */
 
-#define PTRACE_SETOPTIONS         21
-
-/* options set using PTRACE_SETOPTIONS */
-#define PTRACE_O_TRACESYSGOOD     0x00000001
+#define PTRACE_OLDSETOPTIONS         21
 
 #ifndef __ASSEMBLY__
 #include <linux/config.h>
diff -Nru a/include/asm-sh/ptrace.h b/include/asm-sh/ptrace.h
--- a/include/asm-sh/ptrace.h	Thu Oct 31 14:02:17 2002
+++ b/include/asm-sh/ptrace.h	Thu Oct 31 14:02:17 2002
@@ -44,10 +44,7 @@
 #define REG_XDREG14	47
 #define REG_FPSCR	48
 
-#define PTRACE_SETOPTIONS         21
-
-/* options set using PTRACE_SETOPTIONS */
-#define PTRACE_O_TRACESYSGOOD     0x00000001
+#define PTRACE_OLDSETOPTIONS         21
 
 /*
  * This struct defines the way the registers are stored on the
diff -Nru a/include/asm-x86_64/ptrace.h b/include/asm-x86_64/ptrace.h
--- a/include/asm-x86_64/ptrace.h	Thu Oct 31 14:02:16 2002
+++ b/include/asm-x86_64/ptrace.h	Thu Oct 31 14:02:16 2002
@@ -32,10 +32,7 @@
 /* top of stack page */ 
 #define FRAME_SIZE 168
 
-#define PTRACE_SETOPTIONS         21
-
-/* options set using PTRACE_SETOPTIONS */
-#define PTRACE_O_TRACESYSGOOD     0x00000001
+#define PTRACE_OLDSETOPTIONS         21
 
 /* Dummy values for ptrace */ 
 #define FS 1000 
diff -Nru a/include/linux/ptrace.h b/include/linux/ptrace.h
--- a/include/linux/ptrace.h	Thu Oct 31 14:02:16 2002
+++ b/include/linux/ptrace.h	Thu Oct 31 14:02:16 2002
@@ -23,6 +23,12 @@
 
 #define PTRACE_SYSCALL		  24
 
+/* 0x4200-0x4300 are reserved for architecture-independent additions.  */
+#define PTRACE_SETOPTIONS	0x4200
+
+/* options set using PTRACE_SETOPTIONS */
+#define PTRACE_O_TRACESYSGOOD	0x00000001
+
 #include <asm/ptrace.h>
 #include <linux/sched.h>
 
@@ -32,6 +38,7 @@
 extern int ptrace_detach(struct task_struct *, unsigned int);
 extern void ptrace_disable(struct task_struct *);
 extern int ptrace_check_attach(struct task_struct *task, int kill);
+extern int ptrace_request(struct task_struct *child, long request, long addr, long data);
 extern void __ptrace_link(struct task_struct *child,
 				struct task_struct *new_parent);
 extern void __ptrace_unlink(struct task_struct *child);
diff -Nru a/kernel/ptrace.c b/kernel/ptrace.c
--- a/kernel/ptrace.c	Thu Oct 31 14:02:17 2002
+++ b/kernel/ptrace.c	Thu Oct 31 14:02:17 2002
@@ -248,3 +248,35 @@
 	}
 	return copied;
 }
+
+int ptrace_setoptions(struct task_struct *child, long data)
+{
+	if (data & PTRACE_O_TRACESYSGOOD)
+		child->ptrace |= PT_TRACESYSGOOD;
+	else
+		child->ptrace &= ~PT_TRACESYSGOOD;
+
+	if ((data & PTRACE_O_TRACESYSGOOD) != data)
+		return -EINVAL;
+
+	return 0;
+}
+
+int ptrace_request(struct task_struct *child, long request,
+		   long addr, long data)
+{
+	int ret = -EIO;
+
+	switch (request) {
+#ifdef PTRACE_OLDSETOPTIONS
+	case PTRACE_OLDSETOPTIONS:
+#endif
+	case PTRACE_SETOPTIONS:
+		ret = ptrace_setoptions(child, data);
+		break;
+	default:
+		break;
+	}
+
+	return ret;
+}


-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer

Re: PATCH: ptrace support for fork/vfork/clone events [1/3]

[Daniel Jacobowitz]

Here's #2.

# This is a BitKeeper generated patch for the following project:
# Project Name: Linux kernel tree
# This patch format is intended for GNU patch command version 2.5 or higher.
# This patch includes the following deltas:
#	           ChangeSet	1.856   -> 1.857  
#	arch/i386/kernel/process.c	1.32    -> 1.33   
#	arch/alpha/kernel/entry.S	1.15.1.2 -> 1.17   
#	arch/x86_64/kernel/process.c	1.7.1.3 -> 1.9    
#	include/linux/sched.h	1.94.1.15 -> 1.97   
#	arch/sparc/kernel/process.c	1.18    -> 1.19   
#	arch/parisc/kernel/entry.S	1.3.1.1 -> 1.6    
#	arch/mips64/kernel/process.c	1.4     -> 1.5    
#	arch/ppc64/kernel/misc.S	1.28    -> 1.29   
#	arch/mips/kernel/process.c	1.7     -> 1.8    
#	arch/cris/kernel/entry.S	1.12    -> 1.13   
#	arch/sparc64/kernel/process.c	1.35    -> 1.36   
#	arch/ia64/kernel/process.c	1.15.1.3 -> 1.18   
#	arch/m68k/kernel/process.c	1.10    -> 1.11   
#	arch/cris/kernel/entryoffsets.c	1.3     -> 1.4    
#	arch/ppc64/kernel/asm-offsets.c	1.11    -> 1.12   
#	arch/sh/kernel/process.c	1.12    -> 1.13   
#	arch/s390x/kernel/process.c	1.10.1.4 -> 1.12   
#	arch/s390/kernel/process.c	1.12.1.4 -> 1.14   
#	arch/arm/kernel/process.c	1.20    -> 1.21   
#	arch/ppc/kernel/misc.S	1.29    -> 1.30   
#	arch/alpha/kernel/asm-offsets.c	1.6     -> 1.7    
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 02/10/31	drow@nevyn.them.org	1.857
# Merge nevyn.them.org:/nevyn/big/kernel/test/linux-2.5-trace1
# into nevyn.them.org:/nevyn/big/kernel/test/linux-2.5-trace2
# --------------------------------------------
#
diff -Nru a/arch/alpha/kernel/asm-offsets.c b/arch/alpha/kernel/asm-offsets.c
--- a/arch/alpha/kernel/asm-offsets.c	Thu Oct 31 14:02:10 2002
+++ b/arch/alpha/kernel/asm-offsets.c	Thu Oct 31 14:02:10 2002
@@ -22,6 +22,7 @@
 	BLANK();
 	DEFINE(PT_PTRACED, PT_PTRACED);
 	DEFINE(CLONE_VM, CLONE_VM);
+	DEFINE(CLONE_UNTRACED, CLONE_UNTRACED);
 	DEFINE(SIGCHLD, SIGCHLD);
 	BLANK();
 	DEFINE(HAE_CACHE, offsetof(struct alpha_machine_vector, hae_cache));
diff -Nru a/arch/alpha/kernel/entry.S b/arch/alpha/kernel/entry.S
--- a/arch/alpha/kernel/entry.S	Thu Oct 31 14:02:10 2002
+++ b/arch/alpha/kernel/entry.S	Thu Oct 31 14:02:10 2002
@@ -212,7 +212,7 @@
 	stq	$2, 152($30)		/* HAE */
 
 	/* Shuffle FLAGS to the front; add CLONE_VM.  */
-	ldi	$1, CLONE_VM
+	ldi	$1, CLONE_VM|CLONE_UNTRACED
 	or	$18, $1, $16
 	bsr	$26, sys_clone
 
diff -Nru a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
--- a/arch/arm/kernel/process.c	Thu Oct 31 14:02:10 2002
+++ b/arch/arm/kernel/process.c	Thu Oct 31 14:02:10 2002
@@ -403,7 +403,7 @@
 	b	sys_exit					\n\
 1:	"
         : "=r" (__ret)
-        : "Ir" (flags), "I" (CLONE_VM), "r" (fn), "r" (arg)
+        : "Ir" (flags), "r" (CLONE_VM | CLONE_UNTRACED), "r" (fn), "r" (arg)
 	: "r0", "r1", "lr");
 	return __ret;
 }
diff -Nru a/arch/cris/kernel/entry.S b/arch/cris/kernel/entry.S
--- a/arch/cris/kernel/entry.S	Thu Oct 31 14:02:10 2002
+++ b/arch/cris/kernel/entry.S	Thu Oct 31 14:02:10 2002
@@ -748,6 +748,7 @@
 	/* r11 is argument 2 to clone, the flags */
 	move.d  $r12, $r11
 	or.w	LCLONE_VM, $r11
+	or.w	LCLONE_UNTRACED, $r11
 
 	/* Save FN for later.  */
 	move.d	$r10, $r12
diff -Nru a/arch/cris/kernel/entryoffsets.c b/arch/cris/kernel/entryoffsets.c
--- a/arch/cris/kernel/entryoffsets.c	Thu Oct 31 14:02:10 2002
+++ b/arch/cris/kernel/entryoffsets.c	Thu Oct 31 14:02:10 2002
@@ -57,5 +57,6 @@
 
 /* linux/sched.h values - doesn't have an #ifdef __ASSEMBLY__ for these.  */
 VAL (LCLONE_VM, CLONE_VM)
+VAL (LCLONE_UNTRACED, CLONE_UNTRACED)
 
 __asm__ (".endif");
diff -Nru a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
--- a/arch/i386/kernel/process.c	Thu Oct 31 14:02:10 2002
+++ b/arch/i386/kernel/process.c	Thu Oct 31 14:02:10 2002
@@ -224,7 +224,7 @@
 	regs.eflags = 0x286;
 
 	/* Ok, create the new process.. */
-	p = do_fork(flags | CLONE_VM, 0, &regs, 0, NULL);
+	p = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL);
 	return IS_ERR(p) ? PTR_ERR(p) : p->pid;
 }
 
diff -Nru a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
--- a/arch/ia64/kernel/process.c	Thu Oct 31 14:02:10 2002
+++ b/arch/ia64/kernel/process.c	Thu Oct 31 14:02:10 2002
@@ -516,7 +516,7 @@
 	struct task_struct *parent = current;
 	int result, tid;
 
-	tid = clone(flags | CLONE_VM, 0);
+	tid = clone(flags | CLONE_VM | CLONE_UNTRACED, 0);
 	if (parent != current) {
 		result = (*fn)(arg);
 		_exit(result);
diff -Nru a/arch/m68k/kernel/process.c b/arch/m68k/kernel/process.c
--- a/arch/m68k/kernel/process.c	Thu Oct 31 14:02:10 2002
+++ b/arch/m68k/kernel/process.c	Thu Oct 31 14:02:10 2002
@@ -152,7 +152,7 @@
 
 	{
 	register long retval __asm__ ("d0");
-	register long clone_arg __asm__ ("d1") = flags | CLONE_VM;
+	register long clone_arg __asm__ ("d1") = flags | CLONE_VM | CLONE_UNTRACED;
 
 	retval = __NR_clone;
 	__asm__ __volatile__
diff -Nru a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
--- a/arch/mips/kernel/process.c	Thu Oct 31 14:02:10 2002
+++ b/arch/mips/kernel/process.c	Thu Oct 31 14:02:10 2002
@@ -176,7 +176,7 @@
 		:"=r" (retval)
 		:"i" (__NR_clone), "i" (__NR_exit),
 		 "r" (arg), "r" (fn),
-		 "r" (flags | CLONE_VM)
+		 "r" (flags | CLONE_VM | CLONE_UNTRACED)
 		 /*
 		  * The called subroutine might have destroyed any of the
 		  * at, result, argument or temporary registers ...
diff -Nru a/arch/mips64/kernel/process.c b/arch/mips64/kernel/process.c
--- a/arch/mips64/kernel/process.c	Thu Oct 31 14:02:10 2002
+++ b/arch/mips64/kernel/process.c	Thu Oct 31 14:02:10 2002
@@ -167,7 +167,7 @@
 		"1:\tmove\t%0, $2"
 		:"=r" (retval)
 		:"i" (__NR_clone), "i" (__NR_exit), "r" (arg), "r" (fn),
-		 "r" (flags | CLONE_VM)
+		 "r" (flags | CLONE_VM | CLONE_UNTRACED)
 
 		 /* The called subroutine might have destroyed any of the
 		  * at, result, argument or temporary registers ...  */
diff -Nru a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
--- a/arch/parisc/kernel/entry.S	Thu Oct 31 14:02:10 2002
+++ b/arch/parisc/kernel/entry.S	Thu Oct 31 14:02:10 2002
@@ -515,6 +515,7 @@
 	 */
 
 #define CLONE_VM 0x100	/* Must agree with <linux/sched.h> */
+#define CLONE_UNTRACED 0x00800000
 
 	.export __kernel_thread, code
 	.import do_fork
@@ -531,7 +532,8 @@
 #endif
 	STREG	%r26, PT_GR26(%r1)  /* Store function & argument for child */
 	STREG	%r25, PT_GR25(%r1)
-	ldo	CLONE_VM(%r0), %r26   /* Force CLONE_VM since only init_mm */
+	ldil	L%CLONE_UNTRACED, %r26
+	ldo	CLONE_VM(%r26), %r26   /* Force CLONE_VM since only init_mm */
 	or	%r26, %r24, %r26      /* will have kernel mappings.	 */
 	copy	%r0, %r25
 #ifdef __LP64__
diff -Nru a/arch/ppc/kernel/misc.S b/arch/ppc/kernel/misc.S
--- a/arch/ppc/kernel/misc.S	Thu Oct 31 14:02:10 2002
+++ b/arch/ppc/kernel/misc.S	Thu Oct 31 14:02:10 2002
@@ -1005,6 +1005,7 @@
 	mr	r30,r3		/* function */
 	mr	r31,r4		/* argument */
 	ori	r3,r5,CLONE_VM	/* flags */
+	oris	r3,r3,CLONE_UNTRACED>>16
 	li	r0,__NR_clone
 	sc
 	cmpi	0,r3,0		/* parent or child? */
diff -Nru a/arch/ppc64/kernel/asm-offsets.c b/arch/ppc64/kernel/asm-offsets.c
--- a/arch/ppc64/kernel/asm-offsets.c	Thu Oct 31 14:02:10 2002
+++ b/arch/ppc64/kernel/asm-offsets.c	Thu Oct 31 14:02:10 2002
@@ -157,6 +157,7 @@
 	DEFINE(_SRR1, STACK_FRAME_OVERHEAD+sizeof(struct pt_regs)+8);
 
 	DEFINE(CLONE_VM, CLONE_VM);
+	DEFINE(CLONE_UNTRACED, CLONE_UNTRACED);
 
 	return 0;
 }
diff -Nru a/arch/ppc64/kernel/misc.S b/arch/ppc64/kernel/misc.S
--- a/arch/ppc64/kernel/misc.S	Thu Oct 31 14:02:10 2002
+++ b/arch/ppc64/kernel/misc.S	Thu Oct 31 14:02:10 2002
@@ -486,6 +486,7 @@
 	/* XXX fix this when we optimise syscall entry to not save volatiles */
 	mr	r6,r3		/* function */
 	ori	r3,r5,CLONE_VM	/* flags */
+	oris	r3,r3,(CLONE_UNTRACED>>16)
 	li	r0,__NR_clone
 	sc
 	cmpi	0,r3,0		/* parent or child? */
diff -Nru a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
--- a/arch/s390/kernel/process.c	Thu Oct 31 14:02:10 2002
+++ b/arch/s390/kernel/process.c	Thu Oct 31 14:02:10 2002
@@ -146,7 +146,7 @@
 	regs.orig_gpr2 = -1;
 
 	/* Ok, create the new process.. */
-	p = do_fork(flags | CLONE_VM, 0, &regs, 0, NULL);
+	p = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL);
 	return IS_ERR(p) ? PTR_ERR(p) : p->pid;
 }
 
diff -Nru a/arch/s390x/kernel/process.c b/arch/s390x/kernel/process.c
--- a/arch/s390x/kernel/process.c	Thu Oct 31 14:02:10 2002
+++ b/arch/s390x/kernel/process.c	Thu Oct 31 14:02:10 2002
@@ -143,7 +143,7 @@
 	regs.orig_gpr2 = -1;
 
 	/* Ok, create the new process.. */
-	p = do_fork(flags | CLONE_VM, 0, &regs, 0, NULL);
+	p = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL);
 	return IS_ERR(p) ? PTR_ERR(p) : p->pid;
 }
 
diff -Nru a/arch/sh/kernel/process.c b/arch/sh/kernel/process.c
--- a/arch/sh/kernel/process.c	Thu Oct 31 14:02:10 2002
+++ b/arch/sh/kernel/process.c	Thu Oct 31 14:02:10 2002
@@ -120,7 +120,7 @@
 {	/* Don't use this in BL=1(cli).  Or else, CPU resets! */
 	register unsigned long __sc0 __asm__ ("r0");
 	register unsigned long __sc3 __asm__ ("r3") = __NR_clone;
-	register unsigned long __sc4 __asm__ ("r4") = (long) flags | CLONE_VM;
+	register unsigned long __sc4 __asm__ ("r4") = (long) flags | CLONE_VM | CLONE_UNTRACED;
 	register unsigned long __sc5 __asm__ ("r5") = 0;
 	register unsigned long __sc8 __asm__ ("r8") = (long) arg;
 	register unsigned long __sc9 __asm__ ("r9") = (long) fn;
diff -Nru a/arch/sparc/kernel/process.c b/arch/sparc/kernel/process.c
--- a/arch/sparc/kernel/process.c	Thu Oct 31 14:02:10 2002
+++ b/arch/sparc/kernel/process.c	Thu Oct 31 14:02:10 2002
@@ -726,7 +726,7 @@
 			   /* Notreached by child. */
 			   "1: mov %%o0, %0\n\t" :
 			   "=r" (retval) :
-			   "i" (__NR_clone), "r" (flags | CLONE_VM),
+			   "i" (__NR_clone), "r" (flags | CLONE_VM | CLONE_UNTRACED),
 			   "i" (__NR_exit),  "r" (fn), "r" (arg) :
 			   "g1", "g2", "g3", "o0", "o1", "memory", "cc");
 	return retval;
diff -Nru a/arch/sparc64/kernel/process.c b/arch/sparc64/kernel/process.c
--- a/arch/sparc64/kernel/process.c	Thu Oct 31 14:02:10 2002
+++ b/arch/sparc64/kernel/process.c	Thu Oct 31 14:02:10 2002
@@ -694,7 +694,7 @@
 			   /* Notreached by child. */
 			   "1:" :
 			   "=r" (retval) :
-			   "i" (__NR_clone), "r" (flags | CLONE_VM),
+			   "i" (__NR_clone), "r" (flags | CLONE_VM | CLONE_UNTRACED),
 			   "i" (__NR_exit),  "r" (fn), "r" (arg) :
 			   "g1", "g2", "g3", "o0", "o1", "memory", "cc");
 	return retval;
diff -Nru a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c
--- a/arch/x86_64/kernel/process.c	Thu Oct 31 14:02:10 2002
+++ b/arch/x86_64/kernel/process.c	Thu Oct 31 14:02:10 2002
@@ -59,7 +59,7 @@
 asmlinkage extern void ret_from_fork(void);
 int sys_arch_prctl(int code, unsigned long addr);
 
-unsigned long kernel_thread_flags = CLONE_VM;
+unsigned long kernel_thread_flags = CLONE_VM | CLONE_UNTRACED;
 
 int hlt_counter;
 
diff -Nru a/include/linux/sched.h b/include/linux/sched.h
--- a/include/linux/sched.h	Thu Oct 31 14:02:10 2002
+++ b/include/linux/sched.h	Thu Oct 31 14:02:10 2002
@@ -51,6 +51,7 @@
 #define CLONE_SETTID	0x00100000	/* write the TID back to userspace */
 #define CLONE_CLEARTID	0x00200000	/* clear the userspace TID */
 #define CLONE_DETACHED	0x00400000	/* parent wants no child-exit signal */
+#define CLONE_UNTRACED  0x00800000	/* set if the tracing process can't force CLONE_PTRACE on this clone */
 
 /*
  * List of flags we want to share for kernel threads,


-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer

Re: PATCH: ptrace support for fork/vfork/clone events [1/3]

[Daniel Jacobowitz]

And the interesting one, #3.

# This is a BitKeeper generated patch for the following project:
# Project Name: Linux kernel tree
# This patch format is intended for GNU patch command version 2.5 or higher.
# This patch includes the following deltas:
#	           ChangeSet	1.857   -> 1.858  
#	include/linux/sched.h	1.95.1.2 -> 1.98   
#	       kernel/fork.c	1.77.1.12 -> 1.81   
#	include/linux/ptrace.h	1.4     -> 1.5    
#	    fs/binfmt_aout.c	1.12.1.1 -> 1.14   
#	     fs/binfmt_elf.c	1.29    -> 1.30   
#	     kernel/ptrace.c	1.19    -> 1.20   
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 02/10/31	drow@nevyn.them.org	1.858
# Merge nevyn.them.org:/nevyn/big/kernel/test/linux-2.5-trace2
# into nevyn.them.org:/nevyn/big/kernel/test/linux-2.5-trace3
# --------------------------------------------
#
diff -Nru a/fs/binfmt_aout.c b/fs/binfmt_aout.c
--- a/fs/binfmt_aout.c	Thu Oct 31 14:02:04 2002
+++ b/fs/binfmt_aout.c	Thu Oct 31 14:02:04 2002
@@ -425,8 +425,12 @@
 	regs->gp = ex.a_gpvalue;
 #endif
 	start_thread(regs, ex.a_entry, current->mm->start_stack);
-	if (current->ptrace & PT_PTRACED)
-		send_sig(SIGTRAP, current, 0);
+	if (unlikely(current->ptrace & PT_PTRACED)) {
+		if (current->ptrace & PT_TRACE_EXEC)
+			ptrace_notify ((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
+		else
+			send_sig(SIGTRAP, current, 0);
+	}
 	return 0;
 }
 
diff -Nru a/fs/binfmt_elf.c b/fs/binfmt_elf.c
--- a/fs/binfmt_elf.c	Thu Oct 31 14:02:04 2002
+++ b/fs/binfmt_elf.c	Thu Oct 31 14:02:04 2002
@@ -792,8 +792,12 @@
 #endif
 
 	start_thread(regs, elf_entry, bprm->p);
-	if (current->ptrace & PT_PTRACED)
-		send_sig(SIGTRAP, current, 0);
+	if (unlikely(current->ptrace & PT_PTRACED)) {
+		if (current->ptrace & PT_TRACE_EXEC)
+			ptrace_notify ((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
+		else
+			send_sig(SIGTRAP, current, 0);
+	}
 	retval = 0;
 out:
 	return retval;
diff -Nru a/include/linux/ptrace.h b/include/linux/ptrace.h
--- a/include/linux/ptrace.h	Thu Oct 31 14:02:04 2002
+++ b/include/linux/ptrace.h	Thu Oct 31 14:02:04 2002
@@ -25,9 +25,20 @@
 
 /* 0x4200-0x4300 are reserved for architecture-independent additions.  */
 #define PTRACE_SETOPTIONS	0x4200
+#define PTRACE_GETEVENTMSG	0x4201
 
 /* options set using PTRACE_SETOPTIONS */
 #define PTRACE_O_TRACESYSGOOD	0x00000001
+#define PTRACE_O_TRACEFORK	0x00000002
+#define PTRACE_O_TRACEVFORK	0x00000004
+#define PTRACE_O_TRACECLONE	0x00000008
+#define PTRACE_O_TRACEEXEC	0x00000010
+
+/* Wait extended result codes for the above trace options.  */
+#define PTRACE_EVENT_FORK	1
+#define PTRACE_EVENT_VFORK	2
+#define PTRACE_EVENT_CLONE	3
+#define PTRACE_EVENT_EXEC	4
 
 #include <asm/ptrace.h>
 #include <linux/sched.h>
@@ -39,6 +50,7 @@
 extern void ptrace_disable(struct task_struct *);
 extern int ptrace_check_attach(struct task_struct *task, int kill);
 extern int ptrace_request(struct task_struct *child, long request, long addr, long data);
+extern void ptrace_notify(int exit_code);
 extern void __ptrace_link(struct task_struct *child,
 				struct task_struct *new_parent);
 extern void __ptrace_unlink(struct task_struct *child);
diff -Nru a/include/linux/sched.h b/include/linux/sched.h
--- a/include/linux/sched.h	Thu Oct 31 14:02:04 2002
+++ b/include/linux/sched.h	Thu Oct 31 14:02:04 2002
@@ -389,6 +389,8 @@
 	void *journal_info;
 	struct dentry *proc_dentry;
 	struct backing_dev_info *backing_dev_info;
+
+	unsigned long ptrace_message;
 };
 
 extern void __put_task_struct(struct task_struct *tsk);
@@ -427,6 +429,10 @@
 #define PT_DTRACE	0x00000002	/* delayed trace (used on m68k, i386) */
 #define PT_TRACESYSGOOD	0x00000004
 #define PT_PTRACE_CAP	0x00000008	/* ptracer can follow suid-exec */
+#define PT_TRACE_FORK	0x00000010
+#define PT_TRACE_VFORK	0x00000020
+#define PT_TRACE_CLONE	0x00000040
+#define PT_TRACE_EXEC	0x00000080
 
 /*
  * Limit the stack by to some sane default: root can always
diff -Nru a/kernel/fork.c b/kernel/fork.c
--- a/kernel/fork.c	Thu Oct 31 14:02:04 2002
+++ b/kernel/fork.c	Thu Oct 31 14:02:04 2002
@@ -943,6 +943,22 @@
 	goto fork_out;
 }
 
+static inline int fork_traceflag (unsigned clone_flags)
+{
+	if (clone_flags & (CLONE_UNTRACED | CLONE_IDLETASK))
+		return 0;
+	else if (clone_flags & CLONE_VFORK) {
+		if (current->ptrace & PT_TRACE_VFORK)
+			return PTRACE_EVENT_VFORK;
+	} else if ((clone_flags & CSIGNAL) != SIGCHLD) {
+		if (current->ptrace & PT_TRACE_CLONE)
+			return PTRACE_EVENT_CLONE;
+	} else if (current->ptrace & PT_TRACE_FORK)
+		return PTRACE_EVENT_FORK;
+
+	return 0;
+}
+
 /*
  *  Ok, this is the main fork-routine.
  *
@@ -956,6 +972,13 @@
 			    int *user_tid)
 {
 	struct task_struct *p;
+	int trace = 0;
+
+	if (unlikely(current->ptrace)) {
+		trace = fork_traceflag (clone_flags);
+		if (trace)
+			clone_flags |= CLONE_PTRACE;
+	}
 
 	p = copy_process(clone_flags, stack_start, regs, stack_size, user_tid);
 	if (!IS_ERR(p)) {
@@ -971,6 +994,12 @@
 
 		wake_up_forked_process(p);		/* do this last */
 		++total_forks;
+
+		if (unlikely (trace)) {
+			current->ptrace_message = (unsigned long) p->pid;
+			ptrace_notify ((trace << 8) | SIGTRAP);
+		}
+
 		if (clone_flags & CLONE_VFORK)
 			wait_for_completion(&vfork);
 		else
diff -Nru a/kernel/ptrace.c b/kernel/ptrace.c
--- a/kernel/ptrace.c	Thu Oct 31 14:02:04 2002
+++ b/kernel/ptrace.c	Thu Oct 31 14:02:04 2002
@@ -249,14 +249,37 @@
 	return copied;
 }
 
-int ptrace_setoptions(struct task_struct *child, long data)
+static int ptrace_setoptions(struct task_struct *child, long data)
 {
 	if (data & PTRACE_O_TRACESYSGOOD)
 		child->ptrace |= PT_TRACESYSGOOD;
 	else
 		child->ptrace &= ~PT_TRACESYSGOOD;
 
-	if ((data & PTRACE_O_TRACESYSGOOD) != data)
+	if (data & PTRACE_O_TRACEFORK)
+		child->ptrace |= PT_TRACE_FORK;
+	else
+		child->ptrace &= ~PT_TRACE_FORK;
+
+	if (data & PTRACE_O_TRACEVFORK)
+		child->ptrace |= PT_TRACE_VFORK;
+	else
+		child->ptrace &= ~PT_TRACE_VFORK;
+
+	if (data & PTRACE_O_TRACECLONE)
+		child->ptrace |= PT_TRACE_CLONE;
+	else
+		child->ptrace &= ~PT_TRACE_CLONE;
+
+	if (data & PTRACE_O_TRACEEXEC)
+		child->ptrace |= PT_TRACE_EXEC;
+	else
+		child->ptrace &= ~PT_TRACE_EXEC;
+
+	if ((data & (PTRACE_O_TRACESYSGOOD | PTRACE_O_TRACEFORK
+		    | PTRACE_O_TRACEVFORK | PTRACE_O_TRACECLONE
+		    | PTRACE_O_TRACEEXEC))
+	    != data)
 		return -EINVAL;
 
 	return 0;
@@ -274,9 +297,23 @@
 	case PTRACE_SETOPTIONS:
 		ret = ptrace_setoptions(child, data);
 		break;
+	case PTRACE_GETEVENTMSG:
+		ret = put_user(child->ptrace_message, (unsigned long *) data);
+		break;
 	default:
 		break;
 	}
 
 	return ret;
+}
+
+void ptrace_notify(int exit_code)
+{
+	BUG_ON (!(current->ptrace & PT_PTRACED));
+
+	/* Let the debugger run.  */
+	current->exit_code = exit_code;
+	set_current_state(TASK_STOPPED);
+	notify_parent(current, SIGCHLD);
+	schedule();
 }


-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer

PATCH: ptrace support for fork/vfork/clone events [1/3]

[Daniel Jacobowitz]

I've submitted this a couple of times and gotten no feedback, but I'm a
sucker for pain, so here it is again - I'd really like to see this patch in
2.6.

Why?  Without it, there are some things GDB can't do.  You can't step over a
call to fork(), because when you do, the child process will hit the
parent's step breakpoint and exit with SIGTRAP.  You also can't choose to
debug the child instead of the parent, because GDB doesn't have a chance to
attach to it.

The code is in three parts:
 1. Factor out some common ptrace code; implement PTRACE_O_TRACESYSGOOD
    and PTRACE_SETOPTIONS for every architecture.  This one will let me unify
    a great deal more of the architecture ptrace implementations later.
 2. Add a new clone flag, CLONE_UNTRACED, and force it in all kernel_thread
    implementations.  Needed by the next patch.  This one touches every
    architecture and some of them in assembly; I've tried to get them all
    correct.
 3. Add PTRACE_GETEVENTMSG and four new flags to PTRACE_SETOPTIONS, to allow
    tracing fork, vfork, clone, and exec events.

The patches have been tested on i386, and a 2.4 backport tested on SH, MIPS,
i386, PowerPC, and ARM; I have GDB using this mechanism and have run that
through more stress tests than I really want to remember on the weekend.

The three patches are available at:
  http://crack.them.org/~drow/forks/

or from the BK tree at:
  bk://nevyn.them.org:5000

Here's the first one.

# This is a BitKeeper generated patch for the following project:
# Project Name: Linux kernel tree
# This patch format is intended for GNU patch command version 2.5 or higher.
# This patch includes the following deltas:
#	           ChangeSet	1.808   -> 1.809  
#	include/asm-i386/ptrace.h	1.2.1.1 -> 1.4    
#	arch/s390x/kernel/ptrace.c	1.7.1.1 -> 1.9    
#	include/linux/ptrace.h	1.3     -> 1.4    
#	arch/arm/kernel/ptrace.c	1.12.1.2 -> 1.14   
#	arch/sh/kernel/ptrace.c	1.7     -> 1.8    
#	arch/parisc/kernel/ptrace.c	1.4     -> 1.5    
#	include/asm-s390x/ptrace.h	1.3.1.1 -> 1.5    
#	arch/mips64/kernel/ptrace.c	1.6     -> 1.7    
#	arch/ppc/kernel/ptrace.c	1.10    -> 1.11   
#	arch/i386/kernel/ptrace.c	1.13    -> 1.14   
#	arch/x86_64/ia32/ptrace32.c	1.2.1.1 -> 1.4    
#	arch/ppc64/kernel/ptrace.c	1.3.1.1 -> 1.5    
#	arch/m68k/kernel/ptrace.c	1.7     -> 1.8    
#	include/asm-x86_64/ptrace.h	1.3.1.1 -> 1.5    
#	arch/x86_64/kernel/ptrace.c	1.3.1.1 -> 1.5    
#	arch/cris/kernel/ptrace.c	1.8     -> 1.9    
#	arch/ppc64/kernel/ptrace32.c	1.5.1.1 -> 1.7    
#	include/asm-arm/ptrace.h	1.2     -> 1.3    
#	include/asm-mips/ptrace.h	1.2     -> 1.3    
#	arch/ia64/ia32/sys_ia32.c	1.23    -> 1.24   
#	include/asm-ia64/ptrace.h	1.4     -> 1.5    
#	include/asm-s390/ptrace.h	1.5.1.1 -> 1.7    
#	include/asm-sh/ptrace.h	1.2     -> 1.3    
#	arch/alpha/kernel/ptrace.c	1.9     -> 1.10   
#	arch/s390/kernel/ptrace.c	1.8.1.1 -> 1.10   
#	include/asm-mips64/ptrace.h	1.1     -> 1.2    
#	arch/sparc64/kernel/ptrace.c	1.16    -> 1.17   
#	arch/ia64/kernel/ptrace.c	1.11.1.1 -> 1.13   
#	arch/sparc/kernel/ptrace.c	1.11    -> 1.12   
#	arch/mips/kernel/ptrace.c	1.8     -> 1.9    
#	     kernel/ptrace.c	1.18    -> 1.19   
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 02/10/26	drow@nevyn.them.org	1.809
# Merge kernel.org changes
# --------------------------------------------
#
diff -Nru a/arch/alpha/kernel/ptrace.c b/arch/alpha/kernel/ptrace.c
--- a/arch/alpha/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
+++ b/arch/alpha/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
@@ -383,7 +383,7 @@
 		goto out;
 
 	default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		goto out;
 	}
  out:
@@ -400,7 +400,8 @@
 		return;
 	if (!(current->ptrace & PT_PTRACED))
 		return;
-	current->exit_code = SIGTRAP;
+	current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
+					? 0x80 : 0);
 	current->state = TASK_STOPPED;
 	notify_parent(current, SIGCHLD);
 	schedule();
diff -Nru a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c
--- a/arch/arm/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
+++ b/arch/arm/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
@@ -692,16 +692,8 @@
 			ret = ptrace_setfpregs(child, (void *)data);
 			break;
 
-		case PTRACE_SETOPTIONS:
-			if (data & PTRACE_O_TRACESYSGOOD)
-				child->ptrace |= PT_TRACESYSGOOD;
-			else
-				child->ptrace &= ~PT_TRACESYSGOOD;
-			ret = 0;
-			break;
-
 		default:
-			ret = -EIO;
+			ret = ptrace_request(child, request, addr, data);
 			break;
 	}
 
diff -Nru a/arch/cris/kernel/ptrace.c b/arch/cris/kernel/ptrace.c
--- a/arch/cris/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
+++ b/arch/cris/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
@@ -292,7 +292,7 @@
 		}
 
 		default:
-			ret = -EIO;
+			ret = ptrace_request(child, request, addr, data);
 			break;
 	}
 out_tsk:
@@ -307,10 +307,8 @@
 	if ((current->ptrace & (PT_PTRACED | PT_TRACESYS)) !=
 	    (PT_PTRACED | PT_TRACESYS))
 		return;
-	/* TODO: make a way to distinguish between a syscall stop and SIGTRAP
-	 * delivery like in the i386 port ? 
-	 */
-	current->exit_code = SIGTRAP;
+	current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
+					? 0x80 : 0);
 	current->state = TASK_STOPPED;
 	notify_parent(current, SIGCHLD);
 	schedule();
diff -Nru a/arch/i386/kernel/ptrace.c b/arch/i386/kernel/ptrace.c
--- a/arch/i386/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
+++ b/arch/i386/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
@@ -425,17 +425,8 @@
 		break;
 	}
 
-	case PTRACE_SETOPTIONS: {
-		if (data & PTRACE_O_TRACESYSGOOD)
-			child->ptrace |= PT_TRACESYSGOOD;
-		else
-			child->ptrace &= ~PT_TRACESYSGOOD;
-		ret = 0;
-		break;
-	}
-
 	default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		break;
 	}
 out_tsk:
diff -Nru a/arch/ia64/ia32/sys_ia32.c b/arch/ia64/ia32/sys_ia32.c
--- a/arch/ia64/ia32/sys_ia32.c	Sat Oct 26 20:09:49 2002
+++ b/arch/ia64/ia32/sys_ia32.c	Sat Oct 26 20:09:49 2002
@@ -3090,7 +3090,7 @@
 		break;
 
 	      default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		break;
 
 	}
diff -Nru a/arch/ia64/kernel/ptrace.c b/arch/ia64/kernel/ptrace.c
--- a/arch/ia64/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
+++ b/arch/ia64/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
@@ -1268,16 +1268,8 @@
 		ret = ptrace_setregs(child, (struct pt_all_user_regs*) data);
 		goto out_tsk;
 
-	      case PTRACE_SETOPTIONS:
-		if (data & PTRACE_O_TRACESYSGOOD)
-			child->ptrace |= PT_TRACESYSGOOD;
-		else
-			child->ptrace &= ~PT_TRACESYSGOOD;
-		ret = 0;
-		break;
-
 	      default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		goto out_tsk;
 	}
   out_tsk:
diff -Nru a/arch/m68k/kernel/ptrace.c b/arch/m68k/kernel/ptrace.c
--- a/arch/m68k/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
+++ b/arch/m68k/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
@@ -355,7 +355,7 @@
 		}
 
 		default:
-			ret = -EIO;
+			ret = ptrace_request(child, request, addr, data);
 			break;
 	}
 out_tsk:
@@ -370,7 +370,8 @@
 	if (!current->thread.work.delayed_trace &&
 	    !current->thread.work.syscall_trace)
 		return;
-	current->exit_code = SIGTRAP;
+	current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
+					? 0x80 : 0);
 	current->state = TASK_STOPPED;
 	notify_parent(current, SIGCHLD);
 	schedule();
diff -Nru a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
--- a/arch/mips/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
+++ b/arch/mips/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
@@ -304,16 +304,8 @@
 		res = ptrace_detach(child, data);
 		break;
 
-	case PTRACE_SETOPTIONS:
-		if (data & PTRACE_O_TRACESYSGOOD)
-			child->ptrace |= PT_TRACESYSGOOD;
-		else
-			child->ptrace &= ~PT_TRACESYSGOOD;
-		res = 0;
-		break;
-
 	default:
-		res = -EIO;
+		res = ptrace_request(child, request, addr, data);
 		goto out;
 	}
 out_tsk:
diff -Nru a/arch/mips64/kernel/ptrace.c b/arch/mips64/kernel/ptrace.c
--- a/arch/mips64/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
+++ b/arch/mips64/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
@@ -275,17 +275,8 @@
 		ret = ptrace_detach(child, data);
 		break;
 
-	case PTRACE_SETOPTIONS: {
-		if (data & PTRACE_O_TRACESYSGOOD)
-			child->ptrace |= PT_TRACESYSGOOD;
-		else
-			child->ptrace &= ~PT_TRACESYSGOOD;
-		ret = 0;
-		break;
-	}
-
 	default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		break;
 	}
 
@@ -535,17 +526,8 @@
 		ret = ptrace_detach(child, data);
 		break;
 
-	case PTRACE_SETOPTIONS: {
-		if (data & PTRACE_O_TRACESYSGOOD)
-			child->ptrace |= PT_TRACESYSGOOD;
-		else
-			child->ptrace &= ~PT_TRACESYSGOOD;
-		ret = 0;
-		break;
-	}
-
 	default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		break;
 	}
 
diff -Nru a/arch/parisc/kernel/ptrace.c b/arch/parisc/kernel/ptrace.c
--- a/arch/parisc/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
+++ b/arch/parisc/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
@@ -244,7 +244,7 @@
 		goto out_tsk;
 
 	default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		goto out_tsk;
 	}
 
@@ -269,7 +269,8 @@
 	if ((current->ptrace & (PT_PTRACED|PT_TRACESYS)) !=
 			(PT_PTRACED|PT_TRACESYS))
 		return;
-	current->exit_code = SIGTRAP;
+	current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
+					? 0x80 : 0);
 	current->state = TASK_STOPPED;
 	notify_parent(current, SIGCHLD);
 	schedule();
diff -Nru a/arch/ppc/kernel/ptrace.c b/arch/ppc/kernel/ptrace.c
--- a/arch/ppc/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
+++ b/arch/ppc/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
@@ -339,7 +339,7 @@
 #endif
 
 	default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		break;
 	}
 out_tsk:
@@ -354,7 +354,8 @@
         if (!test_thread_flag(TIF_SYSCALL_TRACE)
 	    || !(current->ptrace & PT_PTRACED))
 		return;
-	current->exit_code = SIGTRAP;
+	current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
+					? 0x80 : 0);
 	current->state = TASK_STOPPED;
 	notify_parent(current, SIGCHLD);
 	schedule();
diff -Nru a/arch/ppc64/kernel/ptrace.c b/arch/ppc64/kernel/ptrace.c
--- a/arch/ppc64/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
+++ b/arch/ppc64/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
@@ -276,7 +276,7 @@
 	}
 
 	default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		break;
 	}
 out_tsk:
@@ -292,7 +292,8 @@
 		return;
 	if (!(current->ptrace & PT_PTRACED))
 		return;
-	current->exit_code = SIGTRAP;
+	current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
+					? 0x80 : 0);
 	current->state = TASK_STOPPED;
 	notify_parent(current, SIGCHLD);
 	schedule();
diff -Nru a/arch/ppc64/kernel/ptrace32.c b/arch/ppc64/kernel/ptrace32.c
--- a/arch/ppc64/kernel/ptrace32.c	Sat Oct 26 20:09:49 2002
+++ b/arch/ppc64/kernel/ptrace32.c	Sat Oct 26 20:09:49 2002
@@ -413,7 +413,7 @@
 
 
 	default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		break;
 	}
 out_tsk:
diff -Nru a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
--- a/arch/s390/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
+++ b/arch/s390/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
@@ -307,15 +307,8 @@
 			copied += sizeof(unsigned long);
 		}
 		return 0;
-
-	case PTRACE_SETOPTIONS:
-		if (data & PTRACE_O_TRACESYSGOOD)
-			child->ptrace |= PT_TRACESYSGOOD;
-		else
-			child->ptrace &= ~PT_TRACESYSGOOD;
-		return 0;
 	}
-	return -EIO;
+	return ptrace_request(child, request, addr, data);
 }
 
 asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
diff -Nru a/arch/s390x/kernel/ptrace.c b/arch/s390x/kernel/ptrace.c
--- a/arch/s390x/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
+++ b/arch/s390x/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
@@ -261,7 +261,7 @@
 		}
 		return 0;
 	}
-	return -EIO;
+	return ptrace_request(child, request, addr, data);
 }
 
 #ifdef CONFIG_S390_SUPPORT
@@ -469,7 +469,7 @@
 		}
 		return 0;
 	}
-	return -EIO;
+	return ptrace_request(child, request, addr, data);
 }
 #endif
 
@@ -538,12 +538,6 @@
 		/* detach a process that was attached. */
 		return ptrace_detach(child, data);
 
-	case PTRACE_SETOPTIONS:
-		if (data & PTRACE_O_TRACESYSGOOD)
-			child->ptrace |= PT_TRACESYSGOOD;
-		else
-			child->ptrace &= ~PT_TRACESYSGOOD;
-		return 0;
 	/* Do requests that differ for 31/64 bit */
 	default:
 #ifdef CONFIG_S390_SUPPORT
@@ -551,8 +545,8 @@
 			return do_ptrace_emu31(child, request, addr, data);
 #endif
 		return do_ptrace_normal(child, request, addr, data);
-		
 	}
+	/* Not reached.  */
 	return -EIO;
 }
 
diff -Nru a/arch/sh/kernel/ptrace.c b/arch/sh/kernel/ptrace.c
--- a/arch/sh/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
+++ b/arch/sh/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
@@ -356,17 +356,8 @@
 		ret = ptrace_detach(child, data);
 		break;
 
-	case PTRACE_SETOPTIONS: {
-		if (data & PTRACE_O_TRACESYSGOOD)
-			child->ptrace |= PT_TRACESYSGOOD;
-		else
-			child->ptrace &= ~PT_TRACESYSGOOD;
-		ret = 0;
-		break;
-	}
-
 	default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		break;
 	}
 out_tsk:
diff -Nru a/arch/sparc/kernel/ptrace.c b/arch/sparc/kernel/ptrace.c
--- a/arch/sparc/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
+++ b/arch/sparc/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
@@ -584,10 +584,15 @@
 
 	/* PTRACE_DUMPCORE unsupported... */
 
-	default:
-		pt_error_return(regs, EIO);
+	default: {
+		int err = ptrace_request(child, request, addr, data);
+		if (err)
+			pt_error_return(regs, -err);
+		else
+			pt_succ_return(regs, 0);
 		goto out_tsk;
 	}
+	}
 out_tsk:
 	if (child)
 		put_task_struct(child);
@@ -604,7 +609,8 @@
 		return;
 	if (!(current->ptrace & PT_PTRACED))
 		return;
-	current->exit_code = SIGTRAP;
+	current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
+					? 0x80 : 0);
 	current->state = TASK_STOPPED;
 	current->thread.flags ^= MAGIC_CONSTANT;
 	notify_parent(current, SIGCHLD);
diff -Nru a/arch/sparc64/kernel/ptrace.c b/arch/sparc64/kernel/ptrace.c
--- a/arch/sparc64/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
+++ b/arch/sparc64/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
@@ -571,10 +571,15 @@
 
 	/* PTRACE_DUMPCORE unsupported... */
 
-	default:
-		pt_error_return(regs, EIO);
+	default: {
+		int err = ptrace_request(child, request, addr, data);
+		if (err)
+			pt_error_return(regs, -err);
+		else
+			pt_succ_return(regs, 0);
 		goto out_tsk;
 	}
+	}
 flush_and_out:
 	{
 		unsigned long va;
@@ -612,7 +617,8 @@
 		return;
 	if (!(current->ptrace & PT_PTRACED))
 		return;
-	current->exit_code = SIGTRAP;
+	current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
+					? 0x80 : 0);
 	current->state = TASK_STOPPED;
 	notify_parent(current, SIGCHLD);
 	schedule();
diff -Nru a/arch/x86_64/ia32/ptrace32.c b/arch/x86_64/ia32/ptrace32.c
--- a/arch/x86_64/ia32/ptrace32.c	Sat Oct 26 20:09:49 2002
+++ b/arch/x86_64/ia32/ptrace32.c	Sat Oct 26 20:09:49 2002
@@ -185,17 +185,6 @@
 	__u32 val;
 
 	switch (request) { 
-	case PTRACE_TRACEME:
-	case PTRACE_ATTACH:
-	case PTRACE_SYSCALL:
-	case PTRACE_CONT:
-	case PTRACE_KILL:
-	case PTRACE_SINGLESTEP:
-	case PTRACE_DETACH:
-	case PTRACE_SETOPTIONS:
-		ret = sys_ptrace(request, pid, addr, data); 
-		return ret;
-
 	case PTRACE_PEEKTEXT:
 	case PTRACE_PEEKDATA:
 	case PTRACE_POKEDATA:
@@ -211,7 +200,8 @@
 		break;
 		
 	default:
-		return -EIO;
+		ret = sys_ptrace(request, pid, addr, data); 
+		return ret;
 	} 
 
 	child = find_target(request, pid, &ret);
diff -Nru a/arch/x86_64/kernel/ptrace.c b/arch/x86_64/kernel/ptrace.c
--- a/arch/x86_64/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
+++ b/arch/x86_64/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
@@ -405,17 +405,8 @@
 		break;
 	}
 
-	case PTRACE_SETOPTIONS: {
-		if (data & PTRACE_O_TRACESYSGOOD)
-			child->ptrace |= PT_TRACESYSGOOD;
-		else
-			child->ptrace &= ~PT_TRACESYSGOOD;
-		ret = 0;
-		break;
-	}
-
 	default:
-		ret = -EIO;
+		ret = ptrace_request(child, request, addr, data);
 		break;
 	}
 out_tsk:
diff -Nru a/include/asm-arm/ptrace.h b/include/asm-arm/ptrace.h
--- a/include/asm-arm/ptrace.h	Sat Oct 26 20:09:49 2002
+++ b/include/asm-arm/ptrace.h	Sat Oct 26 20:09:49 2002
@@ -6,10 +6,7 @@
 #define PTRACE_GETFPREGS	14
 #define PTRACE_SETFPREGS	15
 
-#define PTRACE_SETOPTIONS	21
-
-/* options set using PTRACE_SETOPTIONS */
-#define PTRACE_O_TRACESYSGOOD	0x00000001
+#define PTRACE_OLDSETOPTIONS	21
 
 #include <asm/proc/ptrace.h>
 
diff -Nru a/include/asm-i386/ptrace.h b/include/asm-i386/ptrace.h
--- a/include/asm-i386/ptrace.h	Sat Oct 26 20:09:49 2002
+++ b/include/asm-i386/ptrace.h	Sat Oct 26 20:09:49 2002
@@ -49,10 +49,7 @@
 #define PTRACE_GETFPXREGS         18
 #define PTRACE_SETFPXREGS         19
 
-#define PTRACE_SETOPTIONS         21
-
-/* options set using PTRACE_SETOPTIONS */
-#define PTRACE_O_TRACESYSGOOD     0x00000001
+#define PTRACE_OLDSETOPTIONS         21
 
 #ifdef __KERNEL__
 #define user_mode(regs) ((VM_MASK & (regs)->eflags) || (3 & (regs)->xcs))
diff -Nru a/include/asm-ia64/ptrace.h b/include/asm-ia64/ptrace.h
--- a/include/asm-ia64/ptrace.h	Sat Oct 26 20:09:49 2002
+++ b/include/asm-ia64/ptrace.h	Sat Oct 26 20:09:49 2002
@@ -287,9 +287,6 @@
 #define PTRACE_GETREGS		18	/* get all registers (pt_all_user_regs) in one shot */
 #define PTRACE_SETREGS		19	/* set all registers (pt_all_user_regs) in one shot */
 
-#define PTRACE_SETOPTIONS	21
-
-/* options set using PTRACE_SETOPTIONS */
-#define PTRACE_O_TRACESYSGOOD	0x00000001
+#define PTRACE_OLDSETOPTIONS	21
 
 #endif /* _ASM_IA64_PTRACE_H */
diff -Nru a/include/asm-mips/ptrace.h b/include/asm-mips/ptrace.h
--- a/include/asm-mips/ptrace.h	Sat Oct 26 20:09:49 2002
+++ b/include/asm-mips/ptrace.h	Sat Oct 26 20:09:49 2002
@@ -59,10 +59,7 @@
 /* #define PTRACE_GETFPXREGS		18 */
 /* #define PTRACE_SETFPXREGS		19 */
 
-#define PTRACE_SETOPTIONS	21
-
-/* options set using PTRACE_SETOPTIONS */
-#define PTRACE_O_TRACESYSGOOD	0x00000001
+#define PTRACE_OLDSETOPTIONS	21
 
 #ifdef _LANGUAGE_ASSEMBLY
 #include <asm/offset.h>
diff -Nru a/include/asm-mips64/ptrace.h b/include/asm-mips64/ptrace.h
--- a/include/asm-mips64/ptrace.h	Sat Oct 26 20:09:49 2002
+++ b/include/asm-mips64/ptrace.h	Sat Oct 26 20:09:49 2002
@@ -64,10 +64,7 @@
 /* #define PTRACE_GETFPXREGS		18 */
 /* #define PTRACE_SETFPXREGS		19 */
 
-#define PTRACE_SETOPTIONS	21
-
-/* options set using PTRACE_SETOPTIONS */
-#define PTRACE_O_TRACESYSGOOD	0x00000001
+#define PTRACE_OLDSETOPTIONS	21
 
 #ifdef _LANGUAGE_ASSEMBLY
 #include <asm/offset.h>
diff -Nru a/include/asm-s390/ptrace.h b/include/asm-s390/ptrace.h
--- a/include/asm-s390/ptrace.h	Sat Oct 26 20:09:49 2002
+++ b/include/asm-s390/ptrace.h	Sat Oct 26 20:09:49 2002
@@ -105,10 +105,7 @@
 
 #define STACK_FRAME_OVERHEAD	96	/* size of minimum stack frame */
 
-#define PTRACE_SETOPTIONS         21
-
-/* options set using PTRACE_SETOPTIONS */
-#define PTRACE_O_TRACESYSGOOD     0x00000001
+#define PTRACE_OLDSETOPTIONS         21
 
 #ifndef __ASSEMBLY__
 #include <linux/config.h>
diff -Nru a/include/asm-s390x/ptrace.h b/include/asm-s390x/ptrace.h
--- a/include/asm-s390x/ptrace.h	Sat Oct 26 20:09:49 2002
+++ b/include/asm-s390x/ptrace.h	Sat Oct 26 20:09:49 2002
@@ -85,10 +85,7 @@
 
 #define STACK_FRAME_OVERHEAD    160      /* size of minimum stack frame */
 
-#define PTRACE_SETOPTIONS         21
-
-/* options set using PTRACE_SETOPTIONS */
-#define PTRACE_O_TRACESYSGOOD     0x00000001
+#define PTRACE_OLDSETOPTIONS         21
 
 #ifndef __ASSEMBLY__
 #include <linux/config.h>
diff -Nru a/include/asm-sh/ptrace.h b/include/asm-sh/ptrace.h
--- a/include/asm-sh/ptrace.h	Sat Oct 26 20:09:49 2002
+++ b/include/asm-sh/ptrace.h	Sat Oct 26 20:09:49 2002
@@ -44,10 +44,7 @@
 #define REG_XDREG14	47
 #define REG_FPSCR	48
 
-#define PTRACE_SETOPTIONS         21
-
-/* options set using PTRACE_SETOPTIONS */
-#define PTRACE_O_TRACESYSGOOD     0x00000001
+#define PTRACE_OLDSETOPTIONS         21
 
 /*
  * This struct defines the way the registers are stored on the
diff -Nru a/include/asm-x86_64/ptrace.h b/include/asm-x86_64/ptrace.h
--- a/include/asm-x86_64/ptrace.h	Sat Oct 26 20:09:49 2002
+++ b/include/asm-x86_64/ptrace.h	Sat Oct 26 20:09:49 2002
@@ -32,10 +32,7 @@
 /* top of stack page */ 
 #define FRAME_SIZE 168
 
-#define PTRACE_SETOPTIONS         21
-
-/* options set using PTRACE_SETOPTIONS */
-#define PTRACE_O_TRACESYSGOOD     0x00000001
+#define PTRACE_OLDSETOPTIONS         21
 
 /* Dummy values for ptrace */ 
 #define FS 1000 
diff -Nru a/include/linux/ptrace.h b/include/linux/ptrace.h
--- a/include/linux/ptrace.h	Sat Oct 26 20:09:49 2002
+++ b/include/linux/ptrace.h	Sat Oct 26 20:09:49 2002
@@ -23,6 +23,12 @@
 
 #define PTRACE_SYSCALL		  24
 
+/* 0x4200-0x4300 are reserved for architecture-independent additions.  */
+#define PTRACE_SETOPTIONS	0x4200
+
+/* options set using PTRACE_SETOPTIONS */
+#define PTRACE_O_TRACESYSGOOD	0x00000001
+
 #include <asm/ptrace.h>
 #include <linux/sched.h>
 
@@ -32,6 +38,7 @@
 extern int ptrace_detach(struct task_struct *, unsigned int);
 extern void ptrace_disable(struct task_struct *);
 extern int ptrace_check_attach(struct task_struct *task, int kill);
+extern int ptrace_request(struct task_struct *child, long request, long addr, long data);
 extern void __ptrace_link(struct task_struct *child,
 				struct task_struct *new_parent);
 extern void __ptrace_unlink(struct task_struct *child);
diff -Nru a/kernel/ptrace.c b/kernel/ptrace.c
--- a/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
+++ b/kernel/ptrace.c	Sat Oct 26 20:09:49 2002
@@ -248,3 +248,35 @@
 	}
 	return copied;
 }
+
+int ptrace_setoptions(struct task_struct *child, long data)
+{
+	if (data & PTRACE_O_TRACESYSGOOD)
+		child->ptrace |= PT_TRACESYSGOOD;
+	else
+		child->ptrace &= ~PT_TRACESYSGOOD;
+
+	if ((data & PTRACE_O_TRACESYSGOOD) != data)
+		return -EINVAL;
+
+	return 0;
+}
+
+int ptrace_request(struct task_struct *child, long request,
+		   long addr, long data)
+{
+	int ret = -EIO;
+
+	switch (request) {
+#ifdef PTRACE_OLDSETOPTIONS
+	case PTRACE_OLDSETOPTIONS:
+#endif
+	case PTRACE_SETOPTIONS:
+		ret = ptrace_setoptions(child, data);
+		break;
+	default:
+		break;
+	}
+
+	return ret;
+}


-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer

Re: PATCH: ptrace support for fork/vfork/clone events [1/3]

[Alan Cox]

> I've submitted this a couple of times and gotten no feedback, but I'm a
> sucker for pain, so here it is again - I'd really like to see this patch in
> 2.6.

I've been ignoring this because it doesn't appear to agree with what other
people tell me. For example why can't you do the fork trace by building
a trampoline ?

Re: PATCH: ptrace support for fork/vfork/clone events [1/3]

[Daniel Jacobowitz]

On Sun, Oct 27, 2002 at 01:53:17PM -0500, Alan Cox wrote:
> > I've submitted this a couple of times and gotten no feedback, but I'm a
> > sucker for pain, so here it is again - I'd really like to see this patch in
> > 2.6.
> 
> I've been ignoring this because it doesn't appear to agree with what other
> people tell me. For example why can't you do the fork trace by building
> a trampoline ?

This is what strace used to do.  You'll notice that Red Hat's doesn't
any more - not sure if that's in a release yet, Roland was working on
it.  I'm not sure exactly how it works now, but the gist of the problem
was that it's unreliable.  I believe the exact problem he was addressing
was that while strace held the process stopped and figured out the
child's PID, the child got a signal.  It leaves the trampoline and goes
off to handle the signal; strace loses track of it, and it either exits
(confusing the tracer) or longjmps (completely escaping the tracer).

The trampolines are platform-specific, too, which is a real nuisance. 
Some of them are still wrong in the strace source.

Another advantage of ptrace reporting this is that we can stop on these
events without having to manage breakpoints on the syscall points in
libc, which is good when people inline-asm a clone() for some reason;
which does still happen.  GDB can't use PTRACE_SYSCALL to find forks,
it's a substantial slowdown for minimal benefit.

I can probably come up with some more reasons if you want :)

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer

Re: PATCH: ptrace support for fork/vfork/clone events [1/3]

[Daniel Jacobowitz]

On Sun, Oct 27, 2002 at 02:03:11PM -0500, Daniel Jacobowitz wrote:
> On Sun, Oct 27, 2002 at 01:53:17PM -0500, Alan Cox wrote:
> > > I've submitted this a couple of times and gotten no feedback, but I'm a
> > > sucker for pain, so here it is again - I'd really like to see this patch in
> > > 2.6.
> > 
> > I've been ignoring this because it doesn't appear to agree with what other
> > people tell me. For example why can't you do the fork trace by building
> > a trampoline ?
> 
> This is what strace used to do.  You'll notice that Red Hat's doesn't
> any more - not sure if that's in a release yet, Roland was working on
> it.  I'm not sure exactly how it works now, but the gist of the problem
> was that it's unreliable.  I believe the exact problem he was addressing
> was that while strace held the process stopped and figured out the
> child's PID, the child got a signal.  It leaves the trampoline and goes
> off to handle the signal; strace loses track of it, and it either exits
> (confusing the tracer) or longjmps (completely escaping the tracer).
> 
> The trampolines are platform-specific, too, which is a real nuisance. 
> Some of them are still wrong in the strace source.
> 
> Another advantage of ptrace reporting this is that we can stop on these
> events without having to manage breakpoints on the syscall points in
> libc, which is good when people inline-asm a clone() for some reason;
> which does still happen.  GDB can't use PTRACE_SYSCALL to find forks,
> it's a substantial slowdown for minimal benefit.
> 
> I can probably come up with some more reasons if you want :)

Alan, did I manage to convince you this was necessary?

Meanwhile, updated patches to tonight's BK tree are at:
  http://crack.them.org/~drow/forks/
and
  bk://nevyn.them.org:5000

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer