lkml.org 
[lkml]   [2003]   [Feb]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectPtrace updates: event tracing for vfork finish and process exit [4/5]
This patch adds two new event hooks to ptrace:

PTRACE_EVENT_EXIT, which triggers in do_exit(). This is useful to quickly
find out where a program is making an exit syscall from, etc. - it
triggers before the mm is released, so we can still get backtraces et
cetera.

PTRACE_EVENT_VFORK_DONE triggers in do_fork() after the vfork completion,
i.e. when the child is done with the mm. This is a safe way to figure out
when we can re-insert breakpoints in the parent without the child hitting
them. It's the only safe way, in fact.

# --------------------------------------------
# 03/02/06 drow@nevyn.them.org 1.960
# Add PTRACE_O_TRACEVFORKDONE and PTRACE_O_TRACEEXIT facilities.
# --------------------------------------------
diff -Nru a/include/linux/ptrace.h b/include/linux/ptrace.h
--- a/include/linux/ptrace.h Thu Feb 6 16:57:29 2003
+++ b/include/linux/ptrace.h Thu Feb 6 16:57:29 2003
@@ -35,12 +35,16 @@
#define PTRACE_O_TRACEVFORK 0x00000004
#define PTRACE_O_TRACECLONE 0x00000008
#define PTRACE_O_TRACEEXEC 0x00000010
+#define PTRACE_O_TRACEVFORKDONE 0x00000020
+#define PTRACE_O_TRACEEXIT 0x00000040

/* 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
+#define PTRACE_EVENT_VFORK_DONE 5
+#define PTRACE_EVENT_EXIT 6

#include <asm/ptrace.h>
#include <linux/sched.h>
diff -Nru a/include/linux/sched.h b/include/linux/sched.h
--- a/include/linux/sched.h Thu Feb 6 16:57:29 2003
+++ b/include/linux/sched.h Thu Feb 6 16:57:29 2003
@@ -441,6 +441,8 @@
#define PT_TRACE_VFORK 0x00000020
#define PT_TRACE_CLONE 0x00000040
#define PT_TRACE_EXEC 0x00000080
+#define PT_TRACE_VFORK_DONE 0x00000100
+#define PT_TRACE_EXIT 0x00000200

#if CONFIG_SMP
extern void set_cpus_allowed(task_t *p, unsigned long new_mask);
diff -Nru a/kernel/exit.c b/kernel/exit.c
--- a/kernel/exit.c Thu Feb 6 16:57:29 2003
+++ b/kernel/exit.c Thu Feb 6 16:57:29 2003
@@ -653,6 +653,9 @@

profile_exit_task(tsk);

+ if (unlikely(current->ptrace & PT_TRACE_EXIT))
+ ptrace_notify((PTRACE_EVENT_EXIT << 8) | SIGTRAP);
+
fake_volatile:
acct_process(code);
__exit_mm(tsk);
diff -Nru a/kernel/fork.c b/kernel/fork.c
--- a/kernel/fork.c Thu Feb 6 16:57:29 2003
+++ b/kernel/fork.c Thu Feb 6 16:57:29 2003
@@ -1046,9 +1046,11 @@
ptrace_notify ((trace << 8) | SIGTRAP);
}

- if (clone_flags & CLONE_VFORK)
+ if (clone_flags & CLONE_VFORK) {
wait_for_completion(&vfork);
- else
+ if (unlikely (current->ptrace & PT_TRACE_VFORK_DONE))
+ ptrace_notify ((PTRACE_EVENT_VFORK_DONE << 8) | SIGTRAP);
+ } else
/*
* Let the child process run first, to avoid most of the
* COW overhead when the child exec()s afterwards.
diff -Nru a/kernel/ptrace.c b/kernel/ptrace.c
--- a/kernel/ptrace.c Thu Feb 6 16:57:29 2003
+++ b/kernel/ptrace.c Thu Feb 6 16:57:29 2003
@@ -277,9 +277,20 @@
else
child->ptrace &= ~PT_TRACE_EXEC;

+ if (data & PTRACE_O_TRACEVFORKDONE)
+ child->ptrace |= PT_TRACE_VFORK_DONE;
+ else
+ child->ptrace &= ~PT_TRACE_VFORK_DONE;
+
+ if (data & PTRACE_O_TRACEEXIT)
+ child->ptrace |= PT_TRACE_EXIT;
+ else
+ child->ptrace &= ~PT_TRACE_EXIT;
+
if ((data & (PTRACE_O_TRACESYSGOOD | PTRACE_O_TRACEFORK
| PTRACE_O_TRACEVFORK | PTRACE_O_TRACECLONE
- | PTRACE_O_TRACEEXEC))
+ | PTRACE_O_TRACEEXEC | PTRACE_O_TRACEEXIT
+ | PTRACE_O_TRACEVFORKDONE))
!= data)
return -EINVAL;

--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:33    [from the cache]
©2003-2011 Jasper Spaans