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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _LINUX_PTRACE_H
2#define _LINUX_PTRACE_H
Linus Torvalds1da177e2005-04-16 15:20:36 -07003
David Howells607ca462012-10-13 10:46:48 +01004#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. */
Matthew Dempsky4e523652014-06-06 14:36:42 -07008#include <linux/pid_namespace.h> /* For task_active_pid_ns. */
David Howells607ca462012-10-13 10:46:48 +01009#include <uapi/linux/ptrace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070010
Linus Torvalds1da177e2005-04-16 15:20:36 -070011/*
12 * Ptrace flags
Eric W. Biederman260ea102006-06-23 02:05:18 -070013 *
14 * The owner ship rules for task->ptrace which holds the ptrace
15 * flags is simple. When a task is running it owns it's task->ptrace
16 * flags. When the a task is stopped the ptracer owns task->ptrace.
Linus Torvalds1da177e2005-04-16 15:20:36 -070017 */
18
Tejun Heo3544d722011-06-14 11:20:15 +020019#define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#define PT_PTRACED 0x00000001
21#define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */
Denys Vlasenko86b6c1f2012-03-23 15:02:41 -070022#define PT_PTRACE_CAP 0x00000004 /* ptracer can follow suid-exec */
Tejun Heo643ad832011-06-17 16:50:35 +020023
Denys Vlasenko86b6c1f2012-03-23 15:02:41 -070024#define PT_OPT_FLAG_SHIFT 3
Tejun Heo643ad832011-06-17 16:50:35 +020025/* PT_TRACE_* event enable flags */
Denys Vlasenko86b6c1f2012-03-23 15:02:41 -070026#define PT_EVENT_FLAG(event) (1 << (PT_OPT_FLAG_SHIFT + (event)))
27#define PT_TRACESYSGOOD PT_EVENT_FLAG(0)
Tejun Heo643ad832011-06-17 16:50:35 +020028#define PT_TRACE_FORK PT_EVENT_FLAG(PTRACE_EVENT_FORK)
29#define PT_TRACE_VFORK PT_EVENT_FLAG(PTRACE_EVENT_VFORK)
30#define PT_TRACE_CLONE PT_EVENT_FLAG(PTRACE_EVENT_CLONE)
31#define PT_TRACE_EXEC PT_EVENT_FLAG(PTRACE_EVENT_EXEC)
32#define PT_TRACE_VFORK_DONE PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE)
33#define PT_TRACE_EXIT PT_EVENT_FLAG(PTRACE_EVENT_EXIT)
Will Drewryfb0fadf2012-04-12 16:48:02 -050034#define PT_TRACE_SECCOMP PT_EVENT_FLAG(PTRACE_EVENT_SECCOMP)
Linus Torvalds1da177e2005-04-16 15:20:36 -070035
Oleg Nesterov992fb6e2012-12-17 16:03:07 -080036#define PT_EXITKILL (PTRACE_O_EXITKILL << PT_OPT_FLAG_SHIFT)
Tycho Andersen13c4a902015-06-13 09:02:48 -060037#define PT_SUSPEND_SECCOMP (PTRACE_O_SUSPEND_SECCOMP << PT_OPT_FLAG_SHIFT)
Oleg Nesterov992fb6e2012-12-17 16:03:07 -080038
Linus Torvalds1da177e2005-04-16 15:20:36 -070039/* single stepping state bits (used on ARM and PA-RISC) */
40#define PT_SINGLESTEP_BIT 31
41#define PT_SINGLESTEP (1<<PT_SINGLESTEP_BIT)
42#define PT_BLOCKSTEP_BIT 30
43#define PT_BLOCKSTEP (1<<PT_BLOCKSTEP_BIT)
44
Namhyung Kim9b05a692010-10-27 15:33:47 -070045extern long arch_ptrace(struct task_struct *child, long request,
46 unsigned long addr, unsigned long data);
Linus Torvalds1da177e2005-04-16 15:20:36 -070047extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
48extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
Linus Torvalds1da177e2005-04-16 15:20:36 -070049extern void ptrace_disable(struct task_struct *);
Namhyung Kim4abf9862010-10-27 15:33:45 -070050extern int ptrace_request(struct task_struct *child, long request,
51 unsigned long addr, unsigned long data);
Linus Torvalds1da177e2005-04-16 15:20:36 -070052extern void ptrace_notify(int exit_code);
53extern void __ptrace_link(struct task_struct *child,
54 struct task_struct *new_parent);
55extern void __ptrace_unlink(struct task_struct *child);
Oleg Nesterov7c8bd232014-12-10 15:45:33 -080056extern void exit_ptrace(struct task_struct *tracer, struct list_head *dead);
Eric Paris69f594a2012-01-03 12:25:15 -050057#define PTRACE_MODE_READ 0x01
58#define PTRACE_MODE_ATTACH 0x02
59#define PTRACE_MODE_NOAUDIT 0x04
Jann Horncaaee622016-01-20 15:00:04 -080060#define PTRACE_MODE_FSCREDS 0x08
61#define PTRACE_MODE_REALCREDS 0x10
62
63/* shorthands for READ/ATTACH and FSCREDS/REALCREDS combinations */
64#define PTRACE_MODE_READ_FSCREDS (PTRACE_MODE_READ | PTRACE_MODE_FSCREDS)
65#define PTRACE_MODE_READ_REALCREDS (PTRACE_MODE_READ | PTRACE_MODE_REALCREDS)
66#define PTRACE_MODE_ATTACH_FSCREDS (PTRACE_MODE_ATTACH | PTRACE_MODE_FSCREDS)
67#define PTRACE_MODE_ATTACH_REALCREDS (PTRACE_MODE_ATTACH | PTRACE_MODE_REALCREDS)
68
69/**
70 * ptrace_may_access - check whether the caller is permitted to access
71 * a target task.
72 * @task: target task
73 * @mode: selects type of access and caller credentials
74 *
75 * Returns true on success, false on denial.
76 *
77 * One of the flags PTRACE_MODE_FSCREDS and PTRACE_MODE_REALCREDS must
78 * be set in @mode to specify whether the access was requested through
79 * a filesystem syscall (should use effective capabilities and fsuid
80 * of the caller) or through an explicit syscall such as
81 * process_vm_writev or ptrace (and should use the real credentials).
82 */
Stephen Smalley006ebb42008-05-19 08:32:49 -040083extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
Linus Torvalds1da177e2005-04-16 15:20:36 -070084
Oleg Nesterov53b6f9f2008-04-30 00:53:13 -070085static inline int ptrace_reparented(struct task_struct *child)
86{
Oleg Nesterov0347e172011-06-24 17:34:06 +020087 return !same_thread_group(child->real_parent, child->parent);
Oleg Nesterov53b6f9f2008-04-30 00:53:13 -070088}
Oleg Nesterovc6a47cc2009-12-15 16:47:15 -080089
Linus Torvalds1da177e2005-04-16 15:20:36 -070090static inline void ptrace_unlink(struct task_struct *child)
91{
92 if (unlikely(child->ptrace))
93 __ptrace_unlink(child);
94}
95
Namhyung Kim4abf9862010-10-27 15:33:45 -070096int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
97 unsigned long data);
98int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
99 unsigned long data);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100
Roland McGrath88ac2922008-07-25 19:45:43 -0700101/**
Tejun Heo06d98472011-06-17 16:50:40 +0200102 * ptrace_parent - return the task that is tracing the given task
103 * @task: task to consider
104 *
105 * Returns %NULL if no one is tracing @task, or the &struct task_struct
106 * pointer to its tracer.
107 *
108 * Must called under rcu_read_lock(). The pointer returned might be kept
109 * live only by RCU. During exec, this may be called with task_lock() held
110 * on @task, still held from when check_unsafe_exec() was called.
111 */
112static inline struct task_struct *ptrace_parent(struct task_struct *task)
113{
114 if (unlikely(task->ptrace))
115 return rcu_dereference(task->parent);
116 return NULL;
117}
118
119/**
Tejun Heo643ad832011-06-17 16:50:35 +0200120 * ptrace_event_enabled - test whether a ptrace event is enabled
121 * @task: ptracee of interest
122 * @event: %PTRACE_EVENT_* to test
123 *
124 * Test whether @event is enabled for ptracee @task.
125 *
126 * Returns %true if @event is enabled, %false otherwise.
127 */
128static inline bool ptrace_event_enabled(struct task_struct *task, int event)
129{
130 return task->ptrace & PT_EVENT_FLAG(event);
131}
132
133/**
Roland McGrath88ac2922008-07-25 19:45:43 -0700134 * ptrace_event - possibly stop for a ptrace event notification
Tejun Heo643ad832011-06-17 16:50:35 +0200135 * @event: %PTRACE_EVENT_* value to report
Roland McGrath88ac2922008-07-25 19:45:43 -0700136 * @message: value for %PTRACE_GETEVENTMSG to return
137 *
Tejun Heo643ad832011-06-17 16:50:35 +0200138 * Check whether @event is enabled and, if so, report @event and @message
139 * to the ptrace parent.
Roland McGrath88ac2922008-07-25 19:45:43 -0700140 *
Roland McGrath88ac2922008-07-25 19:45:43 -0700141 * Called without locks.
142 */
Tejun Heof3c04b92011-06-17 16:50:36 +0200143static inline void ptrace_event(int event, unsigned long message)
Roland McGrath88ac2922008-07-25 19:45:43 -0700144{
Tejun Heof3c04b92011-06-17 16:50:36 +0200145 if (unlikely(ptrace_event_enabled(current, event))) {
146 current->ptrace_message = message;
147 ptrace_notify((event << 8) | SIGTRAP);
Oleg Nesterovb1845ff2012-03-23 15:02:40 -0700148 } else if (event == PTRACE_EVENT_EXEC) {
Tejun Heof3c04b92011-06-17 16:50:36 +0200149 /* legacy EXEC report via SIGTRAP */
Oleg Nesterovb1845ff2012-03-23 15:02:40 -0700150 if ((current->ptrace & (PT_PTRACED|PT_SEIZED)) == PT_PTRACED)
151 send_sig(SIGTRAP, current, 0);
Tejun Heof3c04b92011-06-17 16:50:36 +0200152 }
Roland McGrath88ac2922008-07-25 19:45:43 -0700153}
154
Roland McGrath09a05392008-07-25 19:45:47 -0700155/**
Matthew Dempsky4e523652014-06-06 14:36:42 -0700156 * ptrace_event_pid - possibly stop for a ptrace event notification
157 * @event: %PTRACE_EVENT_* value to report
158 * @pid: process identifier for %PTRACE_GETEVENTMSG to return
159 *
160 * Check whether @event is enabled and, if so, report @event and @pid
161 * to the ptrace parent. @pid is reported as the pid_t seen from the
162 * the ptrace parent's pid namespace.
163 *
164 * Called without locks.
165 */
166static inline void ptrace_event_pid(int event, struct pid *pid)
167{
168 /*
169 * FIXME: There's a potential race if a ptracer in a different pid
170 * namespace than parent attaches between computing message below and
171 * when we acquire tasklist_lock in ptrace_stop(). If this happens,
172 * the ptracer will get a bogus pid from PTRACE_GETEVENTMSG.
173 */
174 unsigned long message = 0;
175 struct pid_namespace *ns;
176
177 rcu_read_lock();
178 ns = task_active_pid_ns(rcu_dereference(current->parent));
179 if (ns)
180 message = pid_nr_ns(pid, ns);
181 rcu_read_unlock();
182
183 ptrace_event(event, message);
184}
185
186/**
Roland McGrath09a05392008-07-25 19:45:47 -0700187 * ptrace_init_task - initialize ptrace state for a new child
188 * @child: new child task
189 * @ptrace: true if child should be ptrace'd by parent's tracer
190 *
191 * This is called immediately after adding @child to its parent's children
192 * list. @ptrace is false in the normal case, and true to ptrace @child.
193 *
194 * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
195 */
196static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
197{
198 INIT_LIST_HEAD(&child->ptrace_entry);
199 INIT_LIST_HEAD(&child->ptraced);
Oleg Nesterov6634ae12011-07-08 19:13:39 +0200200 child->jobctl = 0;
201 child->ptrace = 0;
202 child->parent = child->real_parent;
203
204 if (unlikely(ptrace) && current->ptrace) {
205 child->ptrace = current->ptrace;
206 __ptrace_link(child, current->parent);
Oleg Nesterovdcace062011-07-08 19:13:54 +0200207
Oleg Nesterovd184d6e2011-07-08 19:14:17 +0200208 if (child->ptrace & PT_SEIZED)
209 task_set_jobctl_pending(child, JOBCTL_TRAP_STOP);
210 else
211 sigaddset(&child->pending.signal, SIGSTOP);
212
Oleg Nesterovdcace062011-07-08 19:13:54 +0200213 set_tsk_thread_flag(child, TIF_SIGPENDING);
Oleg Nesterov6634ae12011-07-08 19:13:39 +0200214 }
Roland McGrath09a05392008-07-25 19:45:47 -0700215}
216
Roland McGrathdae33572008-07-25 19:45:48 -0700217/**
218 * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
219 * @task: task in %EXIT_DEAD state
220 *
221 * Called with write_lock(&tasklist_lock) held.
222 */
223static inline void ptrace_release_task(struct task_struct *task)
224{
225 BUG_ON(!list_empty(&task->ptraced));
226 ptrace_unlink(task);
227 BUG_ON(!list_empty(&task->ptrace_entry));
228}
229
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230#ifndef force_successful_syscall_return
231/*
232 * System call handlers that, upon successful completion, need to return a
233 * negative value should call force_successful_syscall_return() right before
234 * returning. On architectures where the syscall convention provides for a
235 * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
236 * others), this macro can be used to ensure that the error flag will not get
237 * set. On architectures which do not support a separate error flag, the macro
238 * is a no-op and the spurious error condition needs to be filtered out by some
239 * other means (e.g., in user-level, by passing an extra argument to the
240 * syscall handler, or something along those lines).
241 */
242#define force_successful_syscall_return() do { } while (0)
243#endif
244
Eric Parisd7e75282012-01-03 14:23:06 -0500245#ifndef is_syscall_success
246/*
247 * On most systems we can tell if a syscall is a success based on if the retval
248 * is an error value. On some systems like ia64 and powerpc they have different
249 * indicators of success/failure and must define their own.
250 */
251#define is_syscall_success(regs) (!IS_ERR_VALUE((unsigned long)(regs_return_value(regs))))
252#endif
253
Roland McGrathfb7fa8f2008-01-30 13:30:47 +0100254/*
255 * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
256 *
257 * These do-nothing inlines are used when the arch does not
258 * implement single-step. The kerneldoc comments are here
259 * to document the interface for all arch definitions.
260 */
261
262#ifndef arch_has_single_step
263/**
264 * arch_has_single_step - does this CPU support user-mode single-step?
265 *
266 * If this is defined, then there must be function declarations or
267 * inlines for user_enable_single_step() and user_disable_single_step().
268 * arch_has_single_step() should evaluate to nonzero iff the machine
269 * supports instruction single-step for user mode.
270 * It can be a constant or it can test a CPU feature bit.
271 */
272#define arch_has_single_step() (0)
273
274/**
275 * user_enable_single_step - single-step in user-mode task
276 * @task: either current or a task stopped in %TASK_TRACED
277 *
278 * This can only be called when arch_has_single_step() has returned nonzero.
279 * Set @task so that when it returns to user mode, it will trap after the
Roland McGrathdc802c22008-01-30 13:30:53 +0100280 * next single instruction executes. If arch_has_block_step() is defined,
281 * this must clear the effects of user_enable_block_step() too.
Roland McGrathfb7fa8f2008-01-30 13:30:47 +0100282 */
283static inline void user_enable_single_step(struct task_struct *task)
284{
285 BUG(); /* This can never be called. */
286}
287
288/**
289 * user_disable_single_step - cancel user-mode single-step
290 * @task: either current or a task stopped in %TASK_TRACED
291 *
Roland McGrathdc802c22008-01-30 13:30:53 +0100292 * Clear @task of the effects of user_enable_single_step() and
293 * user_enable_block_step(). This can be called whether or not either
294 * of those was ever called on @task, and even if arch_has_single_step()
295 * returned zero.
Roland McGrathfb7fa8f2008-01-30 13:30:47 +0100296 */
297static inline void user_disable_single_step(struct task_struct *task)
298{
299}
Christoph Hellwigdacbe412010-03-10 15:22:46 -0800300#else
301extern void user_enable_single_step(struct task_struct *);
302extern void user_disable_single_step(struct task_struct *);
Roland McGrathfb7fa8f2008-01-30 13:30:47 +0100303#endif /* arch_has_single_step */
304
Roland McGrathdc802c22008-01-30 13:30:53 +0100305#ifndef arch_has_block_step
306/**
307 * arch_has_block_step - does this CPU support user-mode block-step?
308 *
309 * If this is defined, then there must be a function declaration or inline
310 * for user_enable_block_step(), and arch_has_single_step() must be defined
311 * too. arch_has_block_step() should evaluate to nonzero iff the machine
312 * supports step-until-branch for user mode. It can be a constant or it
313 * can test a CPU feature bit.
314 */
Roland McGrath5b88abb2008-01-30 13:30:53 +0100315#define arch_has_block_step() (0)
Roland McGrathdc802c22008-01-30 13:30:53 +0100316
317/**
318 * user_enable_block_step - step until branch in user-mode task
319 * @task: either current or a task stopped in %TASK_TRACED
320 *
321 * This can only be called when arch_has_block_step() has returned nonzero,
322 * and will never be called when single-instruction stepping is being used.
323 * Set @task so that when it returns to user mode, it will trap after the
324 * next branch or trap taken.
325 */
326static inline void user_enable_block_step(struct task_struct *task)
327{
328 BUG(); /* This can never be called. */
329}
Christoph Hellwigdacbe412010-03-10 15:22:46 -0800330#else
331extern void user_enable_block_step(struct task_struct *);
Roland McGrathdc802c22008-01-30 13:30:53 +0100332#endif /* arch_has_block_step */
333
Oleg Nesterov85ec7fd2009-12-15 16:47:17 -0800334#ifdef ARCH_HAS_USER_SINGLE_STEP_INFO
335extern void user_single_step_siginfo(struct task_struct *tsk,
336 struct pt_regs *regs, siginfo_t *info);
337#else
338static inline void user_single_step_siginfo(struct task_struct *tsk,
339 struct pt_regs *regs, siginfo_t *info)
340{
341 memset(info, 0, sizeof(*info));
342 info->si_signo = SIGTRAP;
343}
344#endif
345
Roland McGrath1a669c22008-02-06 01:37:37 -0800346#ifndef arch_ptrace_stop_needed
347/**
348 * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
349 * @code: current->exit_code value ptrace will stop with
350 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
351 *
352 * This is called with the siglock held, to decide whether or not it's
353 * necessary to release the siglock and call arch_ptrace_stop() with the
354 * same @code and @info arguments. It can be defined to a constant if
355 * arch_ptrace_stop() is never required, or always is. On machines where
356 * this makes sense, it should be defined to a quick test to optimize out
357 * calling arch_ptrace_stop() when it would be superfluous. For example,
358 * if the thread has not been back to user mode since the last stop, the
359 * thread state might indicate that nothing needs to be done.
Tejun Heob9cd18d2014-07-03 15:43:15 -0400360 *
361 * This is guaranteed to be invoked once before a task stops for ptrace and
362 * may include arch-specific operations necessary prior to a ptrace stop.
Roland McGrath1a669c22008-02-06 01:37:37 -0800363 */
364#define arch_ptrace_stop_needed(code, info) (0)
365#endif
366
367#ifndef arch_ptrace_stop
368/**
369 * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
370 * @code: current->exit_code value ptrace will stop with
371 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
372 *
373 * This is called with no locks held when arch_ptrace_stop_needed() has
374 * just returned nonzero. It is allowed to block, e.g. for user memory
375 * access. The arch can have machine-specific work to be done before
376 * ptrace stops. On ia64, register backing store gets written back to user
377 * memory here. Since this can be costly (requires dropping the siglock),
378 * we only do it when the arch requires it for this particular stop, as
379 * indicated by arch_ptrace_stop_needed().
380 */
381#define arch_ptrace_stop(code, info) do { } while (0)
382#endif
383
Al Viroa3460a52012-09-30 13:12:36 -0400384#ifndef current_pt_regs
385#define current_pt_regs() task_pt_regs(current)
386#endif
387
Al Viro4f4202f2012-11-05 12:59:15 -0500388#ifndef ptrace_signal_deliver
Al Virob7f95912012-11-05 13:06:22 -0500389#define ptrace_signal_deliver() ((void)0)
Al Viro4f4202f2012-11-05 12:59:15 -0500390#endif
391
Al Viro22062a92012-11-05 13:00:27 -0500392/*
393 * unlike current_pt_regs(), this one is equal to task_pt_regs(current)
394 * on *all* architectures; the only reason to have a per-arch definition
395 * is optimisation.
396 */
397#ifndef signal_pt_regs
398#define signal_pt_regs() task_pt_regs(current)
399#endif
400
Al Viro1ca97bb2012-11-18 12:50:10 -0500401#ifndef current_user_stack_pointer
402#define current_user_stack_pointer() user_stack_pointer(current_pt_regs())
403#endif
404
Roland McGrathbbc69862008-07-25 19:45:59 -0700405extern int task_current_syscall(struct task_struct *target, long *callno,
406 unsigned long args[6], unsigned int maxargs,
407 unsigned long *sp, unsigned long *pc);
408
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409#endif