ptrace.h

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#ifndef _LINUX_PTRACE_H
#define _LINUX_PTRACE_H

#include <linux/compiler.h>     /* For unlikely.  */
#include <linux/sched.h>        /* For struct task_struct.  */
#include <linux/err.h>          /* for IS_ERR_VALUE */
#include <linux/bug.h>          /* For BUG_ON.  */
#include <uapi/linux/ptrace.h>

/*
 * Ptrace flags
 *
 * The owner ship rules for task->ptrace which holds the ptrace
 * flags is simple.  When a task is running it owns it's task->ptrace
 * flags.  When the a task is stopped the ptracer owns task->ptrace.
 */

#define PT_SEIZED   0x00010000  /* SEIZE used, enable new behavior */
#define PT_PTRACED  0x00000001
#define PT_DTRACE   0x00000002  /* delayed trace (used on m68k, i386) */
#define PT_PTRACE_CAP   0x00000004  /* ptracer can follow suid-exec */

#define PT_OPT_FLAG_SHIFT   3
/* PT_TRACE_* event enable flags */
#define PT_EVENT_FLAG(event)    (1 << (PT_OPT_FLAG_SHIFT + (event)))
#define PT_TRACESYSGOOD     PT_EVENT_FLAG(0)
#define PT_TRACE_FORK       PT_EVENT_FLAG(PTRACE_EVENT_FORK)
#define PT_TRACE_VFORK      PT_EVENT_FLAG(PTRACE_EVENT_VFORK)
#define PT_TRACE_CLONE      PT_EVENT_FLAG(PTRACE_EVENT_CLONE)
#define PT_TRACE_EXEC       PT_EVENT_FLAG(PTRACE_EVENT_EXEC)
#define PT_TRACE_VFORK_DONE PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE)
#define PT_TRACE_EXIT       PT_EVENT_FLAG(PTRACE_EVENT_EXIT)
#define PT_TRACE_SECCOMP    PT_EVENT_FLAG(PTRACE_EVENT_SECCOMP)

/* single stepping state bits (used on ARM and PA-RISC) */
#define PT_SINGLESTEP_BIT   31
#define PT_SINGLESTEP       (1<<PT_SINGLESTEP_BIT)
#define PT_BLOCKSTEP_BIT    30
#define PT_BLOCKSTEP        (1<<PT_BLOCKSTEP_BIT)

extern long arch_ptrace(struct task_struct *child, long request,
            unsigned long addr, unsigned long data);
extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
extern void ptrace_disable(struct task_struct *);
extern int ptrace_check_attach(struct task_struct *task, bool ignore_state);
extern int ptrace_request(struct task_struct *child, long request,
              unsigned long addr, unsigned 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);
extern void exit_ptrace(struct task_struct *tracer);
#define PTRACE_MODE_READ    0x01
#define PTRACE_MODE_ATTACH  0x02
#define PTRACE_MODE_NOAUDIT 0x04
/* Returns true on success, false on denial. */
extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);

static inline int ptrace_reparented(struct task_struct *child)
{
    return !same_thread_group(child->real_parent, child->parent);
}

static inline void ptrace_unlink(struct task_struct *child)
{
    if (unlikely(child->ptrace))
        __ptrace_unlink(child);
}

int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
                unsigned long data);
int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
                unsigned long data);

static inline struct task_struct *ptrace_parent(struct task_struct *task)
{
    if (unlikely(task->ptrace))
        return rcu_dereference(task->parent);
    return NULL;
}

static inline bool ptrace_event_enabled(struct task_struct *task, int event)
{
    return task->ptrace & PT_EVENT_FLAG(event);
}

static inline void ptrace_event(int event, unsigned long message)
{
    if (unlikely(ptrace_event_enabled(current, event))) {
        current->ptrace_message = message;
        ptrace_notify((event << 8) | SIGTRAP);
    } else if (event == PTRACE_EVENT_EXEC) {
        /* legacy EXEC report via SIGTRAP */
        if ((current->ptrace & (PT_PTRACED|PT_SEIZED)) == PT_PTRACED)
            send_sig(SIGTRAP, current, 0);
    }
}

static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
{
    INIT_LIST_HEAD(&child->ptrace_entry);
    INIT_LIST_HEAD(&child->ptraced);
#ifdef CONFIG_HAVE_HW_BREAKPOINT
    atomic_set(&child->ptrace_bp_refcnt, 1);
#endif
    child->jobctl = 0;
    child->ptrace = 0;
    child->parent = child->real_parent;

    if (unlikely(ptrace) && current->ptrace) {
        child->ptrace = current->ptrace;
        __ptrace_link(child, current->parent);

        if (child->ptrace & PT_SEIZED)
            task_set_jobctl_pending(child, JOBCTL_TRAP_STOP);
        else
            sigaddset(&child->pending.signal, SIGSTOP);

        set_tsk_thread_flag(child, TIF_SIGPENDING);
    }
}

static inline void ptrace_release_task(struct task_struct *task)
{
    BUG_ON(!list_empty(&task->ptraced));
    ptrace_unlink(task);
    BUG_ON(!list_empty(&task->ptrace_entry));
}

#ifndef force_successful_syscall_return
/*
 * System call handlers that, upon successful completion, need to return a
 * negative value should call force_successful_syscall_return() right before
 * returning.  On architectures where the syscall convention provides for a
 * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
 * others), this macro can be used to ensure that the error flag will not get
 * set.  On architectures which do not support a separate error flag, the macro
 * is a no-op and the spurious error condition needs to be filtered out by some
 * other means (e.g., in user-level, by passing an extra argument to the
 * syscall handler, or something along those lines).
 */
#define force_successful_syscall_return() do { } while (0)
#endif

#ifndef is_syscall_success
/*
 * On most systems we can tell if a syscall is a success based on if the retval
 * is an error value.  On some systems like ia64 and powerpc they have different
 * indicators of success/failure and must define their own.
 */
#define is_syscall_success(regs) (!IS_ERR_VALUE((unsigned long)(regs_return_value(regs))))
#endif

/*
 * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
 *
 * These do-nothing inlines are used when the arch does not
 * implement single-step.  The kerneldoc comments are here
 * to document the interface for all arch definitions.
 */

#ifndef arch_has_single_step

#define arch_has_single_step()      (0)

static inline void user_enable_single_step(struct task_struct *task)
{
    BUG();          /* This can never be called.  */
}

static inline void user_disable_single_step(struct task_struct *task)
{
}
#else
extern void user_enable_single_step(struct task_struct *);
extern void user_disable_single_step(struct task_struct *);
#endif  /* arch_has_single_step */

#ifndef arch_has_block_step

#define arch_has_block_step()       (0)

static inline void user_enable_block_step(struct task_struct *task)
{
    BUG();          /* This can never be called.  */
}
#else
extern void user_enable_block_step(struct task_struct *);
#endif  /* arch_has_block_step */

#ifdef ARCH_HAS_USER_SINGLE_STEP_INFO
extern void user_single_step_siginfo(struct task_struct *tsk,
                struct pt_regs *regs, siginfo_t *info);
#else
static inline void user_single_step_siginfo(struct task_struct *tsk,
                struct pt_regs *regs, siginfo_t *info)
{
    memset(info, 0, sizeof(*info));
    info->si_signo = SIGTRAP;
}
#endif

#ifndef arch_ptrace_stop_needed

#define arch_ptrace_stop_needed(code, info) (0)
#endif

#ifndef arch_ptrace_stop

#define arch_ptrace_stop(code, info)        do { } while (0)
#endif

#ifndef current_pt_regs
#define current_pt_regs() task_pt_regs(current)
#endif

extern int task_current_syscall(struct task_struct *target, long *callno,
                unsigned long args[6], unsigned int maxargs,
                unsigned long *sp, unsigned long *pc);

#ifdef CONFIG_HAVE_HW_BREAKPOINT
extern int ptrace_get_breakpoints(struct task_struct *tsk);
extern void ptrace_put_breakpoints(struct task_struct *tsk);
#else
static inline void ptrace_put_breakpoints(struct task_struct *tsk) { }
#endif /* CONFIG_HAVE_HW_BREAKPOINT */

#endif