ptrace: copy_process() should disable stepping
[deliverable/linux.git] / include / linux / ptrace.h
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1#ifndef _LINUX_PTRACE_H
2#define _LINUX_PTRACE_H
3/* ptrace.h */
4/* structs and defines to help the user use the ptrace system call. */
5
6/* has the defines to get at the registers. */
7
8#define PTRACE_TRACEME 0
9#define PTRACE_PEEKTEXT 1
10#define PTRACE_PEEKDATA 2
11#define PTRACE_PEEKUSR 3
12#define PTRACE_POKETEXT 4
13#define PTRACE_POKEDATA 5
14#define PTRACE_POKEUSR 6
15#define PTRACE_CONT 7
16#define PTRACE_KILL 8
17#define PTRACE_SINGLESTEP 9
18
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19#define PTRACE_ATTACH 16
20#define PTRACE_DETACH 17
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21
22#define PTRACE_SYSCALL 24
23
24/* 0x4200-0x4300 are reserved for architecture-independent additions. */
25#define PTRACE_SETOPTIONS 0x4200
26#define PTRACE_GETEVENTMSG 0x4201
27#define PTRACE_GETSIGINFO 0x4202
28#define PTRACE_SETSIGINFO 0x4203
29
30/* options set using PTRACE_SETOPTIONS */
31#define PTRACE_O_TRACESYSGOOD 0x00000001
32#define PTRACE_O_TRACEFORK 0x00000002
33#define PTRACE_O_TRACEVFORK 0x00000004
34#define PTRACE_O_TRACECLONE 0x00000008
35#define PTRACE_O_TRACEEXEC 0x00000010
36#define PTRACE_O_TRACEVFORKDONE 0x00000020
37#define PTRACE_O_TRACEEXIT 0x00000040
38
39#define PTRACE_O_MASK 0x0000007f
40
41/* Wait extended result codes for the above trace options. */
42#define PTRACE_EVENT_FORK 1
43#define PTRACE_EVENT_VFORK 2
44#define PTRACE_EVENT_CLONE 3
45#define PTRACE_EVENT_EXEC 4
46#define PTRACE_EVENT_VFORK_DONE 5
47#define PTRACE_EVENT_EXIT 6
48
49#include <asm/ptrace.h>
50
51#ifdef __KERNEL__
52/*
53 * Ptrace flags
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54 *
55 * The owner ship rules for task->ptrace which holds the ptrace
56 * flags is simple. When a task is running it owns it's task->ptrace
57 * flags. When the a task is stopped the ptracer owns task->ptrace.
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58 */
59
60#define PT_PTRACED 0x00000001
61#define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */
62#define PT_TRACESYSGOOD 0x00000004
63#define PT_PTRACE_CAP 0x00000008 /* ptracer can follow suid-exec */
64#define PT_TRACE_FORK 0x00000010
65#define PT_TRACE_VFORK 0x00000020
66#define PT_TRACE_CLONE 0x00000040
67#define PT_TRACE_EXEC 0x00000080
68#define PT_TRACE_VFORK_DONE 0x00000100
69#define PT_TRACE_EXIT 0x00000200
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70
71#define PT_TRACE_MASK 0x000003f4
72
73/* single stepping state bits (used on ARM and PA-RISC) */
74#define PT_SINGLESTEP_BIT 31
75#define PT_SINGLESTEP (1<<PT_SINGLESTEP_BIT)
76#define PT_BLOCKSTEP_BIT 30
77#define PT_BLOCKSTEP (1<<PT_BLOCKSTEP_BIT)
78
79#include <linux/compiler.h> /* For unlikely. */
80#include <linux/sched.h> /* For struct task_struct. */
81
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82
83extern long arch_ptrace(struct task_struct *child, long request, long addr, long data);
6b9c7ed8 84extern int ptrace_traceme(void);
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85extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
86extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
87extern int ptrace_attach(struct task_struct *tsk);
88extern int ptrace_detach(struct task_struct *, unsigned int);
89extern void ptrace_disable(struct task_struct *);
90extern int ptrace_check_attach(struct task_struct *task, int kill);
91extern int ptrace_request(struct task_struct *child, long request, long addr, long data);
92extern void ptrace_notify(int exit_code);
93extern void __ptrace_link(struct task_struct *child,
94 struct task_struct *new_parent);
95extern void __ptrace_unlink(struct task_struct *child);
39c626ae 96extern void exit_ptrace(struct task_struct *tracer);
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97#define PTRACE_MODE_READ 1
98#define PTRACE_MODE_ATTACH 2
99/* Returns 0 on success, -errno on denial. */
100extern int __ptrace_may_access(struct task_struct *task, unsigned int mode);
101/* Returns true on success, false on denial. */
102extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
1da177e4 103
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104static inline int ptrace_reparented(struct task_struct *child)
105{
106 return child->real_parent != child->parent;
107}
c6a47cc2 108
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109static inline void ptrace_unlink(struct task_struct *child)
110{
111 if (unlikely(child->ptrace))
112 __ptrace_unlink(child);
113}
114
76647323 115int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data);
f284ce72 116int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data);
1da177e4 117
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118/**
119 * task_ptrace - return %PT_* flags that apply to a task
120 * @task: pointer to &task_struct in question
121 *
122 * Returns the %PT_* flags that apply to @task.
123 */
124static inline int task_ptrace(struct task_struct *task)
125{
126 return task->ptrace;
127}
128
129/**
130 * ptrace_event - possibly stop for a ptrace event notification
131 * @mask: %PT_* bit to check in @current->ptrace
132 * @event: %PTRACE_EVENT_* value to report if @mask is set
133 * @message: value for %PTRACE_GETEVENTMSG to return
134 *
135 * This checks the @mask bit to see if ptrace wants stops for this event.
136 * If so we stop, reporting @event and @message to the ptrace parent.
137 *
138 * Returns nonzero if we did a ptrace notification, zero if not.
139 *
140 * Called without locks.
141 */
142static inline int ptrace_event(int mask, int event, unsigned long message)
143{
144 if (mask && likely(!(current->ptrace & mask)))
145 return 0;
146 current->ptrace_message = message;
147 ptrace_notify((event << 8) | SIGTRAP);
148 return 1;
149}
150
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151/**
152 * ptrace_init_task - initialize ptrace state for a new child
153 * @child: new child task
154 * @ptrace: true if child should be ptrace'd by parent's tracer
155 *
156 * This is called immediately after adding @child to its parent's children
157 * list. @ptrace is false in the normal case, and true to ptrace @child.
158 *
159 * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
160 */
161static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
162{
163 INIT_LIST_HEAD(&child->ptrace_entry);
164 INIT_LIST_HEAD(&child->ptraced);
165 child->parent = child->real_parent;
166 child->ptrace = 0;
c6a47cc2 167 if (unlikely(ptrace) && (current->ptrace & PT_PTRACED)) {
09a05394 168 child->ptrace = current->ptrace;
c6a47cc2 169 __ptrace_link(child, current->parent);
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170 }
171}
172
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173/**
174 * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
175 * @task: task in %EXIT_DEAD state
176 *
177 * Called with write_lock(&tasklist_lock) held.
178 */
179static inline void ptrace_release_task(struct task_struct *task)
180{
181 BUG_ON(!list_empty(&task->ptraced));
182 ptrace_unlink(task);
183 BUG_ON(!list_empty(&task->ptrace_entry));
184}
185
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186#ifndef force_successful_syscall_return
187/*
188 * System call handlers that, upon successful completion, need to return a
189 * negative value should call force_successful_syscall_return() right before
190 * returning. On architectures where the syscall convention provides for a
191 * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
192 * others), this macro can be used to ensure that the error flag will not get
193 * set. On architectures which do not support a separate error flag, the macro
194 * is a no-op and the spurious error condition needs to be filtered out by some
195 * other means (e.g., in user-level, by passing an extra argument to the
196 * syscall handler, or something along those lines).
197 */
198#define force_successful_syscall_return() do { } while (0)
199#endif
200
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201/*
202 * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
203 *
204 * These do-nothing inlines are used when the arch does not
205 * implement single-step. The kerneldoc comments are here
206 * to document the interface for all arch definitions.
207 */
208
209#ifndef arch_has_single_step
210/**
211 * arch_has_single_step - does this CPU support user-mode single-step?
212 *
213 * If this is defined, then there must be function declarations or
214 * inlines for user_enable_single_step() and user_disable_single_step().
215 * arch_has_single_step() should evaluate to nonzero iff the machine
216 * supports instruction single-step for user mode.
217 * It can be a constant or it can test a CPU feature bit.
218 */
219#define arch_has_single_step() (0)
220
221/**
222 * user_enable_single_step - single-step in user-mode task
223 * @task: either current or a task stopped in %TASK_TRACED
224 *
225 * This can only be called when arch_has_single_step() has returned nonzero.
226 * Set @task so that when it returns to user mode, it will trap after the
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227 * next single instruction executes. If arch_has_block_step() is defined,
228 * this must clear the effects of user_enable_block_step() too.
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229 */
230static inline void user_enable_single_step(struct task_struct *task)
231{
232 BUG(); /* This can never be called. */
233}
234
235/**
236 * user_disable_single_step - cancel user-mode single-step
237 * @task: either current or a task stopped in %TASK_TRACED
238 *
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239 * Clear @task of the effects of user_enable_single_step() and
240 * user_enable_block_step(). This can be called whether or not either
241 * of those was ever called on @task, and even if arch_has_single_step()
242 * returned zero.
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243 */
244static inline void user_disable_single_step(struct task_struct *task)
245{
246}
247#endif /* arch_has_single_step */
248
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249#ifndef arch_has_block_step
250/**
251 * arch_has_block_step - does this CPU support user-mode block-step?
252 *
253 * If this is defined, then there must be a function declaration or inline
254 * for user_enable_block_step(), and arch_has_single_step() must be defined
255 * too. arch_has_block_step() should evaluate to nonzero iff the machine
256 * supports step-until-branch for user mode. It can be a constant or it
257 * can test a CPU feature bit.
258 */
5b88abbf 259#define arch_has_block_step() (0)
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260
261/**
262 * user_enable_block_step - step until branch in user-mode task
263 * @task: either current or a task stopped in %TASK_TRACED
264 *
265 * This can only be called when arch_has_block_step() has returned nonzero,
266 * and will never be called when single-instruction stepping is being used.
267 * Set @task so that when it returns to user mode, it will trap after the
268 * next branch or trap taken.
269 */
270static inline void user_enable_block_step(struct task_struct *task)
271{
272 BUG(); /* This can never be called. */
273}
274#endif /* arch_has_block_step */
275
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276#ifndef arch_ptrace_stop_needed
277/**
278 * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
279 * @code: current->exit_code value ptrace will stop with
280 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
281 *
282 * This is called with the siglock held, to decide whether or not it's
283 * necessary to release the siglock and call arch_ptrace_stop() with the
284 * same @code and @info arguments. It can be defined to a constant if
285 * arch_ptrace_stop() is never required, or always is. On machines where
286 * this makes sense, it should be defined to a quick test to optimize out
287 * calling arch_ptrace_stop() when it would be superfluous. For example,
288 * if the thread has not been back to user mode since the last stop, the
289 * thread state might indicate that nothing needs to be done.
290 */
291#define arch_ptrace_stop_needed(code, info) (0)
292#endif
293
294#ifndef arch_ptrace_stop
295/**
296 * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
297 * @code: current->exit_code value ptrace will stop with
298 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
299 *
300 * This is called with no locks held when arch_ptrace_stop_needed() has
301 * just returned nonzero. It is allowed to block, e.g. for user memory
302 * access. The arch can have machine-specific work to be done before
303 * ptrace stops. On ia64, register backing store gets written back to user
304 * memory here. Since this can be costly (requires dropping the siglock),
305 * we only do it when the arch requires it for this particular stop, as
306 * indicated by arch_ptrace_stop_needed().
307 */
308#define arch_ptrace_stop(code, info) do { } while (0)
309#endif
310
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311#ifndef arch_ptrace_untrace
312/*
313 * Do machine-specific work before untracing child.
314 *
315 * This is called for a normal detach as well as from ptrace_exit()
316 * when the tracing task dies.
317 *
318 * Called with write_lock(&tasklist_lock) held.
319 */
320#define arch_ptrace_untrace(task) do { } while (0)
321#endif
322
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323extern int task_current_syscall(struct task_struct *target, long *callno,
324 unsigned long args[6], unsigned int maxargs,
325 unsigned long *sp, unsigned long *pc);
326
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327#endif
328
329#endif
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