Messages in this thread Patch in this message |  | | Date | Thu, 6 Feb 2003 17:42:54 -0500 | From | Daniel Jacobowitz <> | Subject | Ptrace updates: event tracing for vfork finish and process exit [4/5] |
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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/
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