1 #ifndef _LINUX_PTRACE_H
2 #define _LINUX_PTRACE_H
3
4 #include <linux/compiler.h> /* For unlikely. */
5 #include <linux/sched.h> /* For struct task_struct. */
6 #include <linux/err.h> /* for IS_ERR_VALUE */
7 #include <linux/bug.h> /* For BUG_ON. */
8 #include <uapi/linux/ptrace.h>
9
10 /*
11 * Ptrace flags
12 *
13 * The owner ship rules for task->ptrace which holds the ptrace
14 * flags is simple. When a task is running it owns it's task->ptrace
15 * flags. When the a task is stopped the ptracer owns task->ptrace.
16 */
17
18 #define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */
19 #define PT_PTRACED 0x00000001
20 #define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */
21 #define PT_PTRACE_CAP 0x00000004 /* ptracer can follow suid-exec */
22
23 #define PT_OPT_FLAG_SHIFT 3
24 /* PT_TRACE_* event enable flags */
25 #define PT_EVENT_FLAG(event) (1 << (PT_OPT_FLAG_SHIFT + (event)))
26 #define PT_TRACESYSGOOD PT_EVENT_FLAG(0)
27 #define PT_TRACE_FORK PT_EVENT_FLAG(PTRACE_EVENT_FORK)
28 #define PT_TRACE_VFORK PT_EVENT_FLAG(PTRACE_EVENT_VFORK)
29 #define PT_TRACE_CLONE PT_EVENT_FLAG(PTRACE_EVENT_CLONE)
30 #define PT_TRACE_EXEC PT_EVENT_FLAG(PTRACE_EVENT_EXEC)
31 #define PT_TRACE_VFORK_DONE PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE)
32 #define PT_TRACE_EXIT PT_EVENT_FLAG(PTRACE_EVENT_EXIT)
33 #define PT_TRACE_SECCOMP PT_EVENT_FLAG(PTRACE_EVENT_SECCOMP)
34
35 #define PT_EXITKILL (PTRACE_O_EXITKILL << PT_OPT_FLAG_SHIFT)
36
37 /* single stepping state bits (used on ARM and PA-RISC) */
38 #define PT_SINGLESTEP_BIT 31
39 #define PT_SINGLESTEP (1<<PT_SINGLESTEP_BIT)
40 #define PT_BLOCKSTEP_BIT 30
41 #define PT_BLOCKSTEP (1<<PT_BLOCKSTEP_BIT)
42
43 extern long arch_ptrace(struct task_struct *child, long request,
44 unsigned long addr, unsigned long data);
45 extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
46 extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
47 extern void ptrace_disable(struct task_struct *);
48 extern int ptrace_request(struct task_struct *child, long request,
49 unsigned long addr, unsigned long data);
50 extern void ptrace_notify(int exit_code);
51 extern void __ptrace_link(struct task_struct *child,
52 struct task_struct *new_parent);
53 extern void __ptrace_unlink(struct task_struct *child);
54 extern void exit_ptrace(struct task_struct *tracer);
55 #define PTRACE_MODE_READ 0x01
56 #define PTRACE_MODE_ATTACH 0x02
57 #define PTRACE_MODE_NOAUDIT 0x04
58 /* Returns true on success, false on denial. */
59 extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
60
ptrace_reparented(struct task_struct * child)61 static inline int ptrace_reparented(struct task_struct *child)
62 {
63 return !same_thread_group(child->real_parent, child->parent);
64 }
65
ptrace_unlink(struct task_struct * child)66 static inline void ptrace_unlink(struct task_struct *child)
67 {
68 if (unlikely(child->ptrace))
69 __ptrace_unlink(child);
70 }
71
72 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
73 unsigned long data);
74 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
75 unsigned long data);
76
77 /**
78 * ptrace_parent - return the task that is tracing the given task
79 * @task: task to consider
80 *
81 * Returns %NULL if no one is tracing @task, or the &struct task_struct
82 * pointer to its tracer.
83 *
84 * Must called under rcu_read_lock(). The pointer returned might be kept
85 * live only by RCU. During exec, this may be called with task_lock() held
86 * on @task, still held from when check_unsafe_exec() was called.
87 */
ptrace_parent(struct task_struct * task)88 static inline struct task_struct *ptrace_parent(struct task_struct *task)
89 {
90 if (unlikely(task->ptrace))
91 return rcu_dereference(task->parent);
92 return NULL;
93 }
94
95 /**
96 * ptrace_event_enabled - test whether a ptrace event is enabled
97 * @task: ptracee of interest
98 * @event: %PTRACE_EVENT_* to test
99 *
100 * Test whether @event is enabled for ptracee @task.
101 *
102 * Returns %true if @event is enabled, %false otherwise.
103 */
ptrace_event_enabled(struct task_struct * task,int event)104 static inline bool ptrace_event_enabled(struct task_struct *task, int event)
105 {
106 return task->ptrace & PT_EVENT_FLAG(event);
107 }
108
109 /**
110 * ptrace_event - possibly stop for a ptrace event notification
111 * @event: %PTRACE_EVENT_* value to report
112 * @message: value for %PTRACE_GETEVENTMSG to return
113 *
114 * Check whether @event is enabled and, if so, report @event and @message
115 * to the ptrace parent.
116 *
117 * Called without locks.
118 */
ptrace_event(int event,unsigned long message)119 static inline void ptrace_event(int event, unsigned long message)
120 {
121 if (unlikely(ptrace_event_enabled(current, event))) {
122 current->ptrace_message = message;
123 ptrace_notify((event << 8) | SIGTRAP);
124 } else if (event == PTRACE_EVENT_EXEC) {
125 /* legacy EXEC report via SIGTRAP */
126 if ((current->ptrace & (PT_PTRACED|PT_SEIZED)) == PT_PTRACED)
127 send_sig(SIGTRAP, current, 0);
128 }
129 }
130
131 /**
132 * ptrace_init_task - initialize ptrace state for a new child
133 * @child: new child task
134 * @ptrace: true if child should be ptrace'd by parent's tracer
135 *
136 * This is called immediately after adding @child to its parent's children
137 * list. @ptrace is false in the normal case, and true to ptrace @child.
138 *
139 * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
140 */
ptrace_init_task(struct task_struct * child,bool ptrace)141 static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
142 {
143 INIT_LIST_HEAD(&child->ptrace_entry);
144 INIT_LIST_HEAD(&child->ptraced);
145 #ifdef CONFIG_HAVE_HW_BREAKPOINT
146 atomic_set(&child->ptrace_bp_refcnt, 1);
147 #endif
148 child->jobctl = 0;
149 child->ptrace = 0;
150 child->parent = child->real_parent;
151
152 if (unlikely(ptrace) && current->ptrace) {
153 child->ptrace = current->ptrace;
154 __ptrace_link(child, current->parent);
155
156 if (child->ptrace & PT_SEIZED)
157 task_set_jobctl_pending(child, JOBCTL_TRAP_STOP);
158 else
159 sigaddset(&child->pending.signal, SIGSTOP);
160
161 set_tsk_thread_flag(child, TIF_SIGPENDING);
162 }
163 }
164
165 /**
166 * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
167 * @task: task in %EXIT_DEAD state
168 *
169 * Called with write_lock(&tasklist_lock) held.
170 */
ptrace_release_task(struct task_struct * task)171 static inline void ptrace_release_task(struct task_struct *task)
172 {
173 BUG_ON(!list_empty(&task->ptraced));
174 ptrace_unlink(task);
175 BUG_ON(!list_empty(&task->ptrace_entry));
176 }
177
178 #ifndef force_successful_syscall_return
179 /*
180 * System call handlers that, upon successful completion, need to return a
181 * negative value should call force_successful_syscall_return() right before
182 * returning. On architectures where the syscall convention provides for a
183 * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
184 * others), this macro can be used to ensure that the error flag will not get
185 * set. On architectures which do not support a separate error flag, the macro
186 * is a no-op and the spurious error condition needs to be filtered out by some
187 * other means (e.g., in user-level, by passing an extra argument to the
188 * syscall handler, or something along those lines).
189 */
190 #define force_successful_syscall_return() do { } while (0)
191 #endif
192
193 #ifndef is_syscall_success
194 /*
195 * On most systems we can tell if a syscall is a success based on if the retval
196 * is an error value. On some systems like ia64 and powerpc they have different
197 * indicators of success/failure and must define their own.
198 */
199 #define is_syscall_success(regs) (!IS_ERR_VALUE((unsigned long)(regs_return_value(regs))))
200 #endif
201
202 /*
203 * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
204 *
205 * These do-nothing inlines are used when the arch does not
206 * implement single-step. The kerneldoc comments are here
207 * to document the interface for all arch definitions.
208 */
209
210 #ifndef arch_has_single_step
211 /**
212 * arch_has_single_step - does this CPU support user-mode single-step?
213 *
214 * If this is defined, then there must be function declarations or
215 * inlines for user_enable_single_step() and user_disable_single_step().
216 * arch_has_single_step() should evaluate to nonzero iff the machine
217 * supports instruction single-step for user mode.
218 * It can be a constant or it can test a CPU feature bit.
219 */
220 #define arch_has_single_step() (0)
221
222 /**
223 * user_enable_single_step - single-step in user-mode task
224 * @task: either current or a task stopped in %TASK_TRACED
225 *
226 * This can only be called when arch_has_single_step() has returned nonzero.
227 * Set @task so that when it returns to user mode, it will trap after the
228 * next single instruction executes. If arch_has_block_step() is defined,
229 * this must clear the effects of user_enable_block_step() too.
230 */
user_enable_single_step(struct task_struct * task)231 static inline void user_enable_single_step(struct task_struct *task)
232 {
233 BUG(); /* This can never be called. */
234 }
235
236 /**
237 * user_disable_single_step - cancel user-mode single-step
238 * @task: either current or a task stopped in %TASK_TRACED
239 *
240 * Clear @task of the effects of user_enable_single_step() and
241 * user_enable_block_step(). This can be called whether or not either
242 * of those was ever called on @task, and even if arch_has_single_step()
243 * returned zero.
244 */
user_disable_single_step(struct task_struct * task)245 static inline void user_disable_single_step(struct task_struct *task)
246 {
247 }
248 #else
249 extern void user_enable_single_step(struct task_struct *);
250 extern void user_disable_single_step(struct task_struct *);
251 #endif /* arch_has_single_step */
252
253 #ifndef arch_has_block_step
254 /**
255 * arch_has_block_step - does this CPU support user-mode block-step?
256 *
257 * If this is defined, then there must be a function declaration or inline
258 * for user_enable_block_step(), and arch_has_single_step() must be defined
259 * too. arch_has_block_step() should evaluate to nonzero iff the machine
260 * supports step-until-branch for user mode. It can be a constant or it
261 * can test a CPU feature bit.
262 */
263 #define arch_has_block_step() (0)
264
265 /**
266 * user_enable_block_step - step until branch in user-mode task
267 * @task: either current or a task stopped in %TASK_TRACED
268 *
269 * This can only be called when arch_has_block_step() has returned nonzero,
270 * and will never be called when single-instruction stepping is being used.
271 * Set @task so that when it returns to user mode, it will trap after the
272 * next branch or trap taken.
273 */
user_enable_block_step(struct task_struct * task)274 static inline void user_enable_block_step(struct task_struct *task)
275 {
276 BUG(); /* This can never be called. */
277 }
278 #else
279 extern void user_enable_block_step(struct task_struct *);
280 #endif /* arch_has_block_step */
281
282 #ifdef ARCH_HAS_USER_SINGLE_STEP_INFO
283 extern void user_single_step_siginfo(struct task_struct *tsk,
284 struct pt_regs *regs, siginfo_t *info);
285 #else
user_single_step_siginfo(struct task_struct * tsk,struct pt_regs * regs,siginfo_t * info)286 static inline void user_single_step_siginfo(struct task_struct *tsk,
287 struct pt_regs *regs, siginfo_t *info)
288 {
289 memset(info, 0, sizeof(*info));
290 info->si_signo = SIGTRAP;
291 }
292 #endif
293
294 #ifndef arch_ptrace_stop_needed
295 /**
296 * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
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 the siglock held, to decide whether or not it's
301 * necessary to release the siglock and call arch_ptrace_stop() with the
302 * same @code and @info arguments. It can be defined to a constant if
303 * arch_ptrace_stop() is never required, or always is. On machines where
304 * this makes sense, it should be defined to a quick test to optimize out
305 * calling arch_ptrace_stop() when it would be superfluous. For example,
306 * if the thread has not been back to user mode since the last stop, the
307 * thread state might indicate that nothing needs to be done.
308 */
309 #define arch_ptrace_stop_needed(code, info) (0)
310 #endif
311
312 #ifndef arch_ptrace_stop
313 /**
314 * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
315 * @code: current->exit_code value ptrace will stop with
316 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
317 *
318 * This is called with no locks held when arch_ptrace_stop_needed() has
319 * just returned nonzero. It is allowed to block, e.g. for user memory
320 * access. The arch can have machine-specific work to be done before
321 * ptrace stops. On ia64, register backing store gets written back to user
322 * memory here. Since this can be costly (requires dropping the siglock),
323 * we only do it when the arch requires it for this particular stop, as
324 * indicated by arch_ptrace_stop_needed().
325 */
326 #define arch_ptrace_stop(code, info) do { } while (0)
327 #endif
328
329 #ifndef current_pt_regs
330 #define current_pt_regs() task_pt_regs(current)
331 #endif
332
333 #ifndef ptrace_signal_deliver
334 #define ptrace_signal_deliver() ((void)0)
335 #endif
336
337 /*
338 * unlike current_pt_regs(), this one is equal to task_pt_regs(current)
339 * on *all* architectures; the only reason to have a per-arch definition
340 * is optimisation.
341 */
342 #ifndef signal_pt_regs
343 #define signal_pt_regs() task_pt_regs(current)
344 #endif
345
346 #ifndef current_user_stack_pointer
347 #define current_user_stack_pointer() user_stack_pointer(current_pt_regs())
348 #endif
349
350 extern int task_current_syscall(struct task_struct *target, long *callno,
351 unsigned long args[6], unsigned int maxargs,
352 unsigned long *sp, unsigned long *pc);
353
354 #ifdef CONFIG_HAVE_HW_BREAKPOINT
355 extern int ptrace_get_breakpoints(struct task_struct *tsk);
356 extern void ptrace_put_breakpoints(struct task_struct *tsk);
357 #else
ptrace_put_breakpoints(struct task_struct * tsk)358 static inline void ptrace_put_breakpoints(struct task_struct *tsk) { }
359 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
360
361 #endif
362