5861bbfcc1
In the change in commit 09a05394fe
, I
overlooked two nits in the logic and this broke using CLONE_PTRACE
when PTRACE_O_TRACE* are not being used.
A parent that is itself traced at all but not using PTRACE_O_TRACE*,
using CLONE_PTRACE would have its new child fail to be traced.
A parent that is not itself traced at all that uses CLONE_PTRACE
(which should be a no-op in this case) would confuse the bookkeeping
and lead to a crash at exit time.
This restores the missing checks and fixes both failure modes.
Reported-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Roland McGrath <roland@redhat.com>
323 lines
11 KiB
C
323 lines
11 KiB
C
#ifndef _LINUX_PTRACE_H
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#define _LINUX_PTRACE_H
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/* ptrace.h */
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/* structs and defines to help the user use the ptrace system call. */
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/* has the defines to get at the registers. */
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#define PTRACE_TRACEME 0
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#define PTRACE_PEEKTEXT 1
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#define PTRACE_PEEKDATA 2
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#define PTRACE_PEEKUSR 3
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#define PTRACE_POKETEXT 4
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#define PTRACE_POKEDATA 5
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#define PTRACE_POKEUSR 6
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#define PTRACE_CONT 7
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#define PTRACE_KILL 8
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#define PTRACE_SINGLESTEP 9
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#define PTRACE_ATTACH 16
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#define PTRACE_DETACH 17
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#define PTRACE_SYSCALL 24
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/* 0x4200-0x4300 are reserved for architecture-independent additions. */
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#define PTRACE_SETOPTIONS 0x4200
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#define PTRACE_GETEVENTMSG 0x4201
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#define PTRACE_GETSIGINFO 0x4202
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#define PTRACE_SETSIGINFO 0x4203
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/* options set using PTRACE_SETOPTIONS */
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#define PTRACE_O_TRACESYSGOOD 0x00000001
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#define PTRACE_O_TRACEFORK 0x00000002
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#define PTRACE_O_TRACEVFORK 0x00000004
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#define PTRACE_O_TRACECLONE 0x00000008
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#define PTRACE_O_TRACEEXEC 0x00000010
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#define PTRACE_O_TRACEVFORKDONE 0x00000020
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#define PTRACE_O_TRACEEXIT 0x00000040
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#define PTRACE_O_MASK 0x0000007f
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/* Wait extended result codes for the above trace options. */
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#define PTRACE_EVENT_FORK 1
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#define PTRACE_EVENT_VFORK 2
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#define PTRACE_EVENT_CLONE 3
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#define PTRACE_EVENT_EXEC 4
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#define PTRACE_EVENT_VFORK_DONE 5
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#define PTRACE_EVENT_EXIT 6
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#include <asm/ptrace.h>
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#ifdef __KERNEL__
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/*
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* Ptrace flags
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*
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* The owner ship rules for task->ptrace which holds the ptrace
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* flags is simple. When a task is running it owns it's task->ptrace
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* flags. When the a task is stopped the ptracer owns task->ptrace.
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*/
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#define PT_PTRACED 0x00000001
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#define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */
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#define PT_TRACESYSGOOD 0x00000004
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#define PT_PTRACE_CAP 0x00000008 /* ptracer can follow suid-exec */
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#define PT_TRACE_FORK 0x00000010
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#define PT_TRACE_VFORK 0x00000020
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#define PT_TRACE_CLONE 0x00000040
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#define PT_TRACE_EXEC 0x00000080
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#define PT_TRACE_VFORK_DONE 0x00000100
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#define PT_TRACE_EXIT 0x00000200
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#define PT_TRACE_MASK 0x000003f4
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/* single stepping state bits (used on ARM and PA-RISC) */
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#define PT_SINGLESTEP_BIT 31
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#define PT_SINGLESTEP (1<<PT_SINGLESTEP_BIT)
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#define PT_BLOCKSTEP_BIT 30
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#define PT_BLOCKSTEP (1<<PT_BLOCKSTEP_BIT)
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#include <linux/compiler.h> /* For unlikely. */
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#include <linux/sched.h> /* For struct task_struct. */
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extern long arch_ptrace(struct task_struct *child, long request, long addr, long data);
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extern struct task_struct *ptrace_get_task_struct(pid_t pid);
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extern int ptrace_traceme(void);
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extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
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extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
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extern int ptrace_attach(struct task_struct *tsk);
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extern int ptrace_detach(struct task_struct *, unsigned int);
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extern void ptrace_disable(struct task_struct *);
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extern int ptrace_check_attach(struct task_struct *task, int kill);
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extern int ptrace_request(struct task_struct *child, long request, long addr, long data);
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extern void ptrace_notify(int exit_code);
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extern void __ptrace_link(struct task_struct *child,
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struct task_struct *new_parent);
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extern void __ptrace_unlink(struct task_struct *child);
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extern void ptrace_untrace(struct task_struct *child);
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#define PTRACE_MODE_READ 1
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#define PTRACE_MODE_ATTACH 2
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/* Returns 0 on success, -errno on denial. */
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extern int __ptrace_may_access(struct task_struct *task, unsigned int mode);
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/* Returns true on success, false on denial. */
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extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
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static inline int ptrace_reparented(struct task_struct *child)
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{
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return child->real_parent != child->parent;
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}
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static inline void ptrace_link(struct task_struct *child,
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struct task_struct *new_parent)
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{
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if (unlikely(child->ptrace))
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__ptrace_link(child, new_parent);
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}
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static inline void ptrace_unlink(struct task_struct *child)
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{
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if (unlikely(child->ptrace))
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__ptrace_unlink(child);
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}
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int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data);
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int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data);
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/**
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* task_ptrace - return %PT_* flags that apply to a task
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* @task: pointer to &task_struct in question
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*
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* Returns the %PT_* flags that apply to @task.
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*/
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static inline int task_ptrace(struct task_struct *task)
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{
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return task->ptrace;
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}
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/**
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* ptrace_event - possibly stop for a ptrace event notification
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* @mask: %PT_* bit to check in @current->ptrace
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* @event: %PTRACE_EVENT_* value to report if @mask is set
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* @message: value for %PTRACE_GETEVENTMSG to return
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*
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* This checks the @mask bit to see if ptrace wants stops for this event.
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* If so we stop, reporting @event and @message to the ptrace parent.
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*
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* Returns nonzero if we did a ptrace notification, zero if not.
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*
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* Called without locks.
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*/
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static inline int ptrace_event(int mask, int event, unsigned long message)
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{
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if (mask && likely(!(current->ptrace & mask)))
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return 0;
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current->ptrace_message = message;
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ptrace_notify((event << 8) | SIGTRAP);
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return 1;
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}
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/**
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* ptrace_init_task - initialize ptrace state for a new child
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* @child: new child task
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* @ptrace: true if child should be ptrace'd by parent's tracer
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*
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* This is called immediately after adding @child to its parent's children
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* list. @ptrace is false in the normal case, and true to ptrace @child.
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*
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* Called with current's siglock and write_lock_irq(&tasklist_lock) held.
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*/
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static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
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{
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INIT_LIST_HEAD(&child->ptrace_entry);
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INIT_LIST_HEAD(&child->ptraced);
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child->parent = child->real_parent;
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child->ptrace = 0;
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if (unlikely(ptrace)) {
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child->ptrace = current->ptrace;
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ptrace_link(child, current->parent);
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}
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}
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/**
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* ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
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* @task: task in %EXIT_DEAD state
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*
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* Called with write_lock(&tasklist_lock) held.
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*/
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static inline void ptrace_release_task(struct task_struct *task)
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{
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BUG_ON(!list_empty(&task->ptraced));
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ptrace_unlink(task);
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BUG_ON(!list_empty(&task->ptrace_entry));
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}
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#ifndef force_successful_syscall_return
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/*
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* System call handlers that, upon successful completion, need to return a
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* negative value should call force_successful_syscall_return() right before
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* returning. On architectures where the syscall convention provides for a
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* separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
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* others), this macro can be used to ensure that the error flag will not get
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* set. On architectures which do not support a separate error flag, the macro
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* is a no-op and the spurious error condition needs to be filtered out by some
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* other means (e.g., in user-level, by passing an extra argument to the
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* syscall handler, or something along those lines).
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*/
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#define force_successful_syscall_return() do { } while (0)
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#endif
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/*
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* <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
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*
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* These do-nothing inlines are used when the arch does not
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* implement single-step. The kerneldoc comments are here
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* to document the interface for all arch definitions.
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*/
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#ifndef arch_has_single_step
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/**
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* arch_has_single_step - does this CPU support user-mode single-step?
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*
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* If this is defined, then there must be function declarations or
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* inlines for user_enable_single_step() and user_disable_single_step().
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* arch_has_single_step() should evaluate to nonzero iff the machine
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* supports instruction single-step for user mode.
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* It can be a constant or it can test a CPU feature bit.
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*/
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#define arch_has_single_step() (0)
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/**
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* user_enable_single_step - single-step in user-mode task
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* @task: either current or a task stopped in %TASK_TRACED
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*
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* This can only be called when arch_has_single_step() has returned nonzero.
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* Set @task so that when it returns to user mode, it will trap after the
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* next single instruction executes. If arch_has_block_step() is defined,
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* this must clear the effects of user_enable_block_step() too.
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*/
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static inline void user_enable_single_step(struct task_struct *task)
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{
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BUG(); /* This can never be called. */
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}
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/**
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* user_disable_single_step - cancel user-mode single-step
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* @task: either current or a task stopped in %TASK_TRACED
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*
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* Clear @task of the effects of user_enable_single_step() and
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* user_enable_block_step(). This can be called whether or not either
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* of those was ever called on @task, and even if arch_has_single_step()
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* returned zero.
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*/
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static inline void user_disable_single_step(struct task_struct *task)
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{
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}
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#endif /* arch_has_single_step */
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#ifndef arch_has_block_step
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/**
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* arch_has_block_step - does this CPU support user-mode block-step?
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*
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* If this is defined, then there must be a function declaration or inline
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* for user_enable_block_step(), and arch_has_single_step() must be defined
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* too. arch_has_block_step() should evaluate to nonzero iff the machine
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* supports step-until-branch for user mode. It can be a constant or it
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* can test a CPU feature bit.
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*/
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#define arch_has_block_step() (0)
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/**
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* user_enable_block_step - step until branch in user-mode task
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* @task: either current or a task stopped in %TASK_TRACED
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*
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* This can only be called when arch_has_block_step() has returned nonzero,
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* and will never be called when single-instruction stepping is being used.
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* Set @task so that when it returns to user mode, it will trap after the
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* next branch or trap taken.
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*/
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static inline void user_enable_block_step(struct task_struct *task)
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{
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BUG(); /* This can never be called. */
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}
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#endif /* arch_has_block_step */
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#ifndef arch_ptrace_stop_needed
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/**
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* arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
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* @code: current->exit_code value ptrace will stop with
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* @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
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*
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* This is called with the siglock held, to decide whether or not it's
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* necessary to release the siglock and call arch_ptrace_stop() with the
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* same @code and @info arguments. It can be defined to a constant if
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* arch_ptrace_stop() is never required, or always is. On machines where
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* this makes sense, it should be defined to a quick test to optimize out
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* calling arch_ptrace_stop() when it would be superfluous. For example,
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* if the thread has not been back to user mode since the last stop, the
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* thread state might indicate that nothing needs to be done.
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*/
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#define arch_ptrace_stop_needed(code, info) (0)
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#endif
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#ifndef arch_ptrace_stop
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/**
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* arch_ptrace_stop - Do machine-specific work before stopping for ptrace
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* @code: current->exit_code value ptrace will stop with
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* @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
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*
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* This is called with no locks held when arch_ptrace_stop_needed() has
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* just returned nonzero. It is allowed to block, e.g. for user memory
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* access. The arch can have machine-specific work to be done before
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* ptrace stops. On ia64, register backing store gets written back to user
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* memory here. Since this can be costly (requires dropping the siglock),
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* we only do it when the arch requires it for this particular stop, as
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* indicated by arch_ptrace_stop_needed().
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*/
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#define arch_ptrace_stop(code, info) do { } while (0)
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#endif
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extern int task_current_syscall(struct task_struct *target, long *callno,
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unsigned long args[6], unsigned int maxargs,
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unsigned long *sp, unsigned long *pc);
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#endif
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#endif
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