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/*
* Tracing hooks
*
* Copyright (C) 2008-2009 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License v.2.
*
* This file defines hook entry points called by core code where
* user tracing/debugging support might need to do something. These
* entry points are called tracehook_*(). Each hook declared below
* has a detailed kerneldoc comment giving the context (locking et
* al) from which it is called, and the meaning of its return value.
*
* Each function here typically has only one call site, so it is ok
* to have some nontrivial tracehook_*() inlines. In all cases, the
* fast path when no tracing is enabled should be very short.
*
* The purpose of this file and the tracehook_* layer is to consolidate
* the interface that the kernel core and arch code uses to enable any
* user debugging or tracing facility (such as ptrace). The interfaces
* here are carefully documented so that maintainers of core and arch
* code do not need to think about the implementation details of the
* tracing facilities. Likewise, maintainers of the tracing code do not
* need to understand all the calling core or arch code in detail, just
* documented circumstances of each call, such as locking conditions.
*
* If the calling core code changes so that locking is different, then
* it is ok to change the interface documented here. The maintainer of
* core code changing should notify the maintainers of the tracing code
* that they need to work out the change.
*
* Some tracehook_*() inlines take arguments that the current tracing
* implementations might not necessarily use. These function signatures
* are chosen to pass in all the information that is on hand in the
* caller and might conceivably be relevant to a tracer, so that the
* core code won't have to be updated when tracing adds more features.
* If a call site changes so that some of those parameters are no longer
* already on hand without extra work, then the tracehook_* interface
* can change so there is no make-work burden on the core code. The
* maintainer of core code changing should notify the maintainers of the
* tracing code that they need to work out the change.
*/
#ifndef _LINUX_TRACEHOOK_H
#define _LINUX_TRACEHOOK_H 1
#include <linux/sched.h>
#include <linux/ptrace.h>
#include <linux/security.h>
struct linux_binprm;
static inline int ptrace_report_syscall(struct pt_regs *regs)
{
int ptrace = current->ptrace;
if (!(ptrace & PT_PTRACED))
return 0;
ptrace_notify(SIGTRAP | ((ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));
if (current->exit_code) {
send_sig(current->exit_code, current, 1);
current->exit_code = 0;
}
return fatal_signal_pending(current);
}
static inline __must_check int tracehook_report_syscall_entry(
struct pt_regs *regs)
{
return ptrace_report_syscall(regs);
}
static inline void tracehook_report_syscall_exit(struct pt_regs *regs, int step)
{
if (step) {
siginfo_t info;
user_single_step_siginfo(current, regs, &info);
force_sig_info(SIGTRAP, &info, current);
return;
}
ptrace_report_syscall(regs);
}
static inline void tracehook_signal_handler(int sig, siginfo_t *info,
const struct k_sigaction *ka,
struct pt_regs *regs, int stepping)
{
if (stepping)
ptrace_notify(SIGTRAP);
}
#ifdef TIF_NOTIFY_RESUME
static inline void set_notify_resume(struct task_struct *task)
{
if (!test_and_set_tsk_thread_flag(task, TIF_NOTIFY_RESUME))
kick_process(task);
}
static inline void tracehook_notify_resume(struct pt_regs *regs)
{
}
#endif
#endif
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