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Add support for PTRACE_FORK. NB: This does not (yet) work for vfork(), because: 

1. When we vfork() PL_PPWAIT is set, and that makes us do regular disposition
   of the TRAP signal, and not indirect through the debugger.
2. The parent needs to keep running, so that the debugger can release it.
   Unfortunately, with vfork() we cannot release the parent because it will
   eventually core-dump since the parent and the child cannot run on the
   same address space.
This commit is contained in:
christos 2011-09-02 20:06:29 +00:00
parent bac4b71fcb
commit b4ab627dec
1 changed files with 44 additions and 2 deletions
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46
sys/kern/kern_fork.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: kern_fork.c,v 1.185 2011/08/23 13:01:25 christos Exp $ */
/* $NetBSD: kern_fork.c,v 1.186 2011/09/02 20:06:29 christos Exp $ */
/*-
* Copyright (c) 1999, 2001, 2004, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@ -67,7 +67,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_fork.c,v 1.185 2011/08/23 13:01:25 christos Exp $");
__KERNEL_RCSID(0, "$NetBSD: kern_fork.c,v 1.186 2011/09/02 20:06:29 christos Exp $");
#include "opt_ktrace.h"
@ -92,6 +92,7 @@ __KERNEL_RCSID(0, "$NetBSD: kern_fork.c,v 1.185 2011/08/23 13:01:25 christos Exp
#include <sys/syscallargs.h>
#include <sys/uidinfo.h>
#include <sys/sdt.h>
#include <sys/ptrace.h>
#include <uvm/uvm_extern.h>
@ -218,6 +219,7 @@ fork1(struct lwp *l1, int flags, int exitsig, void *stack, size_t stacksize,
int count;
vaddr_t uaddr;
int tnprocs;
int tracefork;
int error = 0;
p1 = l1->l_proc;
@ -458,6 +460,35 @@ fork1(struct lwp *l1, int flags, int exitsig, void *stack, size_t stacksize,
LIST_INSERT_HEAD(&parent->p_children, p2, p_sibling);
p2->p_exitsig = exitsig; /* signal for parent on exit */
tracefork = (p1->p_slflag & (PSL_TRACEFORK|PSL_TRACED)) ==
(PSL_TRACEFORK|PSL_TRACED);
if (tracefork) {
p2->p_slflag |= PSL_TRACED;
p2->p_opptr = p2->p_pptr;
if (p2->p_pptr != p1->p_pptr) {
struct proc *parent1 = p2->p_pptr;
if (parent1->p_lock < p2->p_lock) {
if (!mutex_tryenter(parent1->p_lock)) {
mutex_exit(p2->p_lock);
mutex_enter(parent1->p_lock);
}
} else if (parent1->p_lock > p2->p_lock) {
mutex_enter(parent1->p_lock);
}
parent1->p_slflag |= PSL_CHTRACED;
proc_reparent(p2, p1->p_pptr);
if (parent1->p_lock != p2->p_lock)
mutex_exit(parent1->p_lock);
}
/*
* Set ptrace status.
*/
p1->p_fpid = p2->p_pid;
p2->p_fpid = p1->p_pid;
}
LIST_INSERT_AFTER(p1, p2, p_pglist);
LIST_INSERT_HEAD(&allproc, p2, p_list);
@ -538,6 +569,17 @@ fork1(struct lwp *l1, int flags, int exitsig, void *stack, size_t stacksize,
while (p2->p_lflag & PL_PPWAIT)
cv_wait(&p1->p_waitcv, proc_lock);
/*
* Let the parent know that we are tracing its child.
*/
if (tracefork) {
ksiginfo_t ksi;
KSI_INIT_EMPTY(&ksi);
ksi.ksi_signo = SIGTRAP;
ksi.ksi_lid = l1->l_lid;
kpsignal(p1, &ksi, NULL);
}
mutex_exit(proc_lock);
/*