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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_PTRACE_H
3#define _LINUX_PTRACE_H
4
5#include <linux/compiler.h> /* For unlikely. */
6#include <linux/sched.h> /* For struct task_struct. */
7#include <linux/sched/signal.h> /* For send_sig(), same_thread_group(), etc. */
8#include <linux/err.h> /* for IS_ERR_VALUE */
9#include <linux/bug.h> /* For BUG_ON. */
10#include <linux/pid_namespace.h> /* For task_active_pid_ns. */
11#include <uapi/linux/ptrace.h>
12#include <linux/seccomp.h>
13
14/* Add sp to seccomp_data, as seccomp is user API, we don't want to modify it */
15struct syscall_info {
16 __u64 sp;
17 struct seccomp_data data;
18};
19
20extern int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
21 void *buf, int len, unsigned int gup_flags);
22
23/*
24 * Ptrace flags
25 *
26 * The owner ship rules for task->ptrace which holds the ptrace
27 * flags is simple. When a task is running it owns it's task->ptrace
28 * flags. When the a task is stopped the ptracer owns task->ptrace.
29 */
30
31#define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */
32#define PT_PTRACED 0x00000001
33#define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */
34
35#define PT_OPT_FLAG_SHIFT 3
36/* PT_TRACE_* event enable flags */
37#define PT_EVENT_FLAG(event) (1 << (PT_OPT_FLAG_SHIFT + (event)))
38#define PT_TRACESYSGOOD PT_EVENT_FLAG(0)
39#define PT_TRACE_FORK PT_EVENT_FLAG(PTRACE_EVENT_FORK)
40#define PT_TRACE_VFORK PT_EVENT_FLAG(PTRACE_EVENT_VFORK)
41#define PT_TRACE_CLONE PT_EVENT_FLAG(PTRACE_EVENT_CLONE)
42#define PT_TRACE_EXEC PT_EVENT_FLAG(PTRACE_EVENT_EXEC)
43#define PT_TRACE_VFORK_DONE PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE)
44#define PT_TRACE_EXIT PT_EVENT_FLAG(PTRACE_EVENT_EXIT)
45#define PT_TRACE_SECCOMP PT_EVENT_FLAG(PTRACE_EVENT_SECCOMP)
46
47#define PT_EXITKILL (PTRACE_O_EXITKILL << PT_OPT_FLAG_SHIFT)
48#define PT_SUSPEND_SECCOMP (PTRACE_O_SUSPEND_SECCOMP << PT_OPT_FLAG_SHIFT)
49
50/* single stepping state bits (used on ARM and PA-RISC) */
51#define PT_SINGLESTEP_BIT 31
52#define PT_SINGLESTEP (1<<PT_SINGLESTEP_BIT)
53#define PT_BLOCKSTEP_BIT 30
54#define PT_BLOCKSTEP (1<<PT_BLOCKSTEP_BIT)
55
56extern long arch_ptrace(struct task_struct *child, long request,
57 unsigned long addr, unsigned long data);
58extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
59extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
60extern void ptrace_disable(struct task_struct *);
61extern int ptrace_request(struct task_struct *child, long request,
62 unsigned long addr, unsigned long data);
63extern void ptrace_notify(int exit_code);
64extern void __ptrace_link(struct task_struct *child,
65 struct task_struct *new_parent,
66 const struct cred *ptracer_cred);
67extern void __ptrace_unlink(struct task_struct *child);
68extern void exit_ptrace(struct task_struct *tracer, struct list_head *dead);
69#define PTRACE_MODE_READ 0x01
70#define PTRACE_MODE_ATTACH 0x02
71#define PTRACE_MODE_NOAUDIT 0x04
72#define PTRACE_MODE_FSCREDS 0x08
73#define PTRACE_MODE_REALCREDS 0x10
74
75/* shorthands for READ/ATTACH and FSCREDS/REALCREDS combinations */
76#define PTRACE_MODE_READ_FSCREDS (PTRACE_MODE_READ | PTRACE_MODE_FSCREDS)
77#define PTRACE_MODE_READ_REALCREDS (PTRACE_MODE_READ | PTRACE_MODE_REALCREDS)
78#define PTRACE_MODE_ATTACH_FSCREDS (PTRACE_MODE_ATTACH | PTRACE_MODE_FSCREDS)
79#define PTRACE_MODE_ATTACH_REALCREDS (PTRACE_MODE_ATTACH | PTRACE_MODE_REALCREDS)
80
81/**
82 * ptrace_may_access - check whether the caller is permitted to access
83 * a target task.
84 * @task: target task
85 * @mode: selects type of access and caller credentials
86 *
87 * Returns true on success, false on denial.
88 *
89 * One of the flags PTRACE_MODE_FSCREDS and PTRACE_MODE_REALCREDS must
90 * be set in @mode to specify whether the access was requested through
91 * a filesystem syscall (should use effective capabilities and fsuid
92 * of the caller) or through an explicit syscall such as
93 * process_vm_writev or ptrace (and should use the real credentials).
94 */
95extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
96
97static inline int ptrace_reparented(struct task_struct *child)
98{
99 return !same_thread_group(child->real_parent, child->parent);
100}
101
102static inline void ptrace_unlink(struct task_struct *child)
103{
104 if (unlikely(child->ptrace))
105 __ptrace_unlink(child);
106}
107
108int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
109 unsigned long data);
110int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
111 unsigned long data);
112
113/**
114 * ptrace_parent - return the task that is tracing the given task
115 * @task: task to consider
116 *
117 * Returns %NULL if no one is tracing @task, or the &struct task_struct
118 * pointer to its tracer.
119 *
120 * Must called under rcu_read_lock(). The pointer returned might be kept
121 * live only by RCU. During exec, this may be called with task_lock() held
122 * on @task, still held from when check_unsafe_exec() was called.
123 */
124static inline struct task_struct *ptrace_parent(struct task_struct *task)
125{
126 if (unlikely(task->ptrace))
127 return rcu_dereference(task->parent);
128 return NULL;
129}
130
131/**
132 * ptrace_event_enabled - test whether a ptrace event is enabled
133 * @task: ptracee of interest
134 * @event: %PTRACE_EVENT_* to test
135 *
136 * Test whether @event is enabled for ptracee @task.
137 *
138 * Returns %true if @event is enabled, %false otherwise.
139 */
140static inline bool ptrace_event_enabled(struct task_struct *task, int event)
141{
142 return task->ptrace & PT_EVENT_FLAG(event);
143}
144
145/**
146 * ptrace_event - possibly stop for a ptrace event notification
147 * @event: %PTRACE_EVENT_* value to report
148 * @message: value for %PTRACE_GETEVENTMSG to return
149 *
150 * Check whether @event is enabled and, if so, report @event and @message
151 * to the ptrace parent.
152 *
153 * Called without locks.
154 */
155static inline void ptrace_event(int event, unsigned long message)
156{
157 if (unlikely(ptrace_event_enabled(current, event))) {
158 current->ptrace_message = message;
159 ptrace_notify((event << 8) | SIGTRAP);
160 } else if (event == PTRACE_EVENT_EXEC) {
161 /* legacy EXEC report via SIGTRAP */
162 if ((current->ptrace & (PT_PTRACED|PT_SEIZED)) == PT_PTRACED)
163 send_sig(SIGTRAP, current, 0);
164 }
165}
166
167/**
168 * ptrace_event_pid - possibly stop for a ptrace event notification
169 * @event: %PTRACE_EVENT_* value to report
170 * @pid: process identifier for %PTRACE_GETEVENTMSG to return
171 *
172 * Check whether @event is enabled and, if so, report @event and @pid
173 * to the ptrace parent. @pid is reported as the pid_t seen from the
174 * ptrace parent's pid namespace.
175 *
176 * Called without locks.
177 */
178static inline void ptrace_event_pid(int event, struct pid *pid)
179{
180 /*
181 * FIXME: There's a potential race if a ptracer in a different pid
182 * namespace than parent attaches between computing message below and
183 * when we acquire tasklist_lock in ptrace_stop(). If this happens,
184 * the ptracer will get a bogus pid from PTRACE_GETEVENTMSG.
185 */
186 unsigned long message = 0;
187 struct pid_namespace *ns;
188
189 rcu_read_lock();
190 ns = task_active_pid_ns(rcu_dereference(current->parent));
191 if (ns)
192 message = pid_nr_ns(pid, ns);
193 rcu_read_unlock();
194
195 ptrace_event(event, message);
196}
197
198/**
199 * ptrace_init_task - initialize ptrace state for a new child
200 * @child: new child task
201 * @ptrace: true if child should be ptrace'd by parent's tracer
202 *
203 * This is called immediately after adding @child to its parent's children
204 * list. @ptrace is false in the normal case, and true to ptrace @child.
205 *
206 * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
207 */
208static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
209{
210 INIT_LIST_HEAD(&child->ptrace_entry);
211 INIT_LIST_HEAD(&child->ptraced);
212 child->jobctl = 0;
213 child->ptrace = 0;
214 child->parent = child->real_parent;
215
216 if (unlikely(ptrace) && current->ptrace) {
217 child->ptrace = current->ptrace;
218 __ptrace_link(child, current->parent, current->ptracer_cred);
219
220 if (child->ptrace & PT_SEIZED)
221 task_set_jobctl_pending(child, JOBCTL_TRAP_STOP);
222 else
223 sigaddset(&child->pending.signal, SIGSTOP);
224 }
225 else
226 child->ptracer_cred = NULL;
227}
228
229/**
230 * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
231 * @task: task in %EXIT_DEAD state
232 *
233 * Called with write_lock(&tasklist_lock) held.
234 */
235static inline void ptrace_release_task(struct task_struct *task)
236{
237 BUG_ON(!list_empty(&task->ptraced));
238 ptrace_unlink(task);
239 BUG_ON(!list_empty(&task->ptrace_entry));
240}
241
242#ifndef force_successful_syscall_return
243/*
244 * System call handlers that, upon successful completion, need to return a
245 * negative value should call force_successful_syscall_return() right before
246 * returning. On architectures where the syscall convention provides for a
247 * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
248 * others), this macro can be used to ensure that the error flag will not get
249 * set. On architectures which do not support a separate error flag, the macro
250 * is a no-op and the spurious error condition needs to be filtered out by some
251 * other means (e.g., in user-level, by passing an extra argument to the
252 * syscall handler, or something along those lines).
253 */
254#define force_successful_syscall_return() do { } while (0)
255#endif
256
257#ifndef is_syscall_success
258/*
259 * On most systems we can tell if a syscall is a success based on if the retval
260 * is an error value. On some systems like ia64 and powerpc they have different
261 * indicators of success/failure and must define their own.
262 */
263#define is_syscall_success(regs) (!IS_ERR_VALUE((unsigned long)(regs_return_value(regs))))
264#endif
265
266/*
267 * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
268 *
269 * These do-nothing inlines are used when the arch does not
270 * implement single-step. The kerneldoc comments are here
271 * to document the interface for all arch definitions.
272 */
273
274#ifndef arch_has_single_step
275/**
276 * arch_has_single_step - does this CPU support user-mode single-step?
277 *
278 * If this is defined, then there must be function declarations or
279 * inlines for user_enable_single_step() and user_disable_single_step().
280 * arch_has_single_step() should evaluate to nonzero iff the machine
281 * supports instruction single-step for user mode.
282 * It can be a constant or it can test a CPU feature bit.
283 */
284#define arch_has_single_step() (0)
285
286/**
287 * user_enable_single_step - single-step in user-mode task
288 * @task: either current or a task stopped in %TASK_TRACED
289 *
290 * This can only be called when arch_has_single_step() has returned nonzero.
291 * Set @task so that when it returns to user mode, it will trap after the
292 * next single instruction executes. If arch_has_block_step() is defined,
293 * this must clear the effects of user_enable_block_step() too.
294 */
295static inline void user_enable_single_step(struct task_struct *task)
296{
297 BUG(); /* This can never be called. */
298}
299
300/**
301 * user_disable_single_step - cancel user-mode single-step
302 * @task: either current or a task stopped in %TASK_TRACED
303 *
304 * Clear @task of the effects of user_enable_single_step() and
305 * user_enable_block_step(). This can be called whether or not either
306 * of those was ever called on @task, and even if arch_has_single_step()
307 * returned zero.
308 */
309static inline void user_disable_single_step(struct task_struct *task)
310{
311}
312#else
313extern void user_enable_single_step(struct task_struct *);
314extern void user_disable_single_step(struct task_struct *);
315#endif /* arch_has_single_step */
316
317#ifndef arch_has_block_step
318/**
319 * arch_has_block_step - does this CPU support user-mode block-step?
320 *
321 * If this is defined, then there must be a function declaration or inline
322 * for user_enable_block_step(), and arch_has_single_step() must be defined
323 * too. arch_has_block_step() should evaluate to nonzero iff the machine
324 * supports step-until-branch for user mode. It can be a constant or it
325 * can test a CPU feature bit.
326 */
327#define arch_has_block_step() (0)
328
329/**
330 * user_enable_block_step - step until branch in user-mode task
331 * @task: either current or a task stopped in %TASK_TRACED
332 *
333 * This can only be called when arch_has_block_step() has returned nonzero,
334 * and will never be called when single-instruction stepping is being used.
335 * Set @task so that when it returns to user mode, it will trap after the
336 * next branch or trap taken.
337 */
338static inline void user_enable_block_step(struct task_struct *task)
339{
340 BUG(); /* This can never be called. */
341}
342#else
343extern void user_enable_block_step(struct task_struct *);
344#endif /* arch_has_block_step */
345
346#ifdef ARCH_HAS_USER_SINGLE_STEP_REPORT
347extern void user_single_step_report(struct pt_regs *regs);
348#else
349static inline void user_single_step_report(struct pt_regs *regs)
350{
351 kernel_siginfo_t info;
352 clear_siginfo(&info);
353 info.si_signo = SIGTRAP;
354 info.si_errno = 0;
355 info.si_code = SI_USER;
356 info.si_pid = 0;
357 info.si_uid = 0;
358 force_sig_info(&info);
359}
360#endif
361
362#ifndef arch_ptrace_stop_needed
363/**
364 * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
365 * @code: current->exit_code value ptrace will stop with
366 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
367 *
368 * This is called with the siglock held, to decide whether or not it's
369 * necessary to release the siglock and call arch_ptrace_stop() with the
370 * same @code and @info arguments. It can be defined to a constant if
371 * arch_ptrace_stop() is never required, or always is. On machines where
372 * this makes sense, it should be defined to a quick test to optimize out
373 * calling arch_ptrace_stop() when it would be superfluous. For example,
374 * if the thread has not been back to user mode since the last stop, the
375 * thread state might indicate that nothing needs to be done.
376 *
377 * This is guaranteed to be invoked once before a task stops for ptrace and
378 * may include arch-specific operations necessary prior to a ptrace stop.
379 */
380#define arch_ptrace_stop_needed(code, info) (0)
381#endif
382
383#ifndef arch_ptrace_stop
384/**
385 * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
386 * @code: current->exit_code value ptrace will stop with
387 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
388 *
389 * This is called with no locks held when arch_ptrace_stop_needed() has
390 * just returned nonzero. It is allowed to block, e.g. for user memory
391 * access. The arch can have machine-specific work to be done before
392 * ptrace stops. On ia64, register backing store gets written back to user
393 * memory here. Since this can be costly (requires dropping the siglock),
394 * we only do it when the arch requires it for this particular stop, as
395 * indicated by arch_ptrace_stop_needed().
396 */
397#define arch_ptrace_stop(code, info) do { } while (0)
398#endif
399
400#ifndef current_pt_regs
401#define current_pt_regs() task_pt_regs(current)
402#endif
403
404/*
405 * unlike current_pt_regs(), this one is equal to task_pt_regs(current)
406 * on *all* architectures; the only reason to have a per-arch definition
407 * is optimisation.
408 */
409#ifndef signal_pt_regs
410#define signal_pt_regs() task_pt_regs(current)
411#endif
412
413#ifndef current_user_stack_pointer
414#define current_user_stack_pointer() user_stack_pointer(current_pt_regs())
415#endif
416
417extern int task_current_syscall(struct task_struct *target, struct syscall_info *info);
418
419extern void sigaction_compat_abi(struct k_sigaction *act, struct k_sigaction *oact);
420#endif
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 <linux/pid_namespace.h> /* For task_active_pid_ns. */
9#include <uapi/linux/ptrace.h>
10
11/*
12 * Ptrace flags
13 *
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.
17 */
18
19#define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */
20#define PT_PTRACED 0x00000001
21#define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */
22#define PT_PTRACE_CAP 0x00000004 /* ptracer can follow suid-exec */
23
24#define PT_OPT_FLAG_SHIFT 3
25/* PT_TRACE_* event enable flags */
26#define PT_EVENT_FLAG(event) (1 << (PT_OPT_FLAG_SHIFT + (event)))
27#define PT_TRACESYSGOOD PT_EVENT_FLAG(0)
28#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)
34#define PT_TRACE_SECCOMP PT_EVENT_FLAG(PTRACE_EVENT_SECCOMP)
35
36#define PT_EXITKILL (PTRACE_O_EXITKILL << PT_OPT_FLAG_SHIFT)
37#define PT_SUSPEND_SECCOMP (PTRACE_O_SUSPEND_SECCOMP << PT_OPT_FLAG_SHIFT)
38
39/* 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
45extern long arch_ptrace(struct task_struct *child, long request,
46 unsigned long addr, unsigned long data);
47extern 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);
49extern void ptrace_disable(struct task_struct *);
50extern int ptrace_request(struct task_struct *child, long request,
51 unsigned long addr, unsigned long data);
52extern 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);
56extern void exit_ptrace(struct task_struct *tracer, struct list_head *dead);
57#define PTRACE_MODE_READ 0x01
58#define PTRACE_MODE_ATTACH 0x02
59#define PTRACE_MODE_NOAUDIT 0x04
60#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 */
83extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
84
85static inline int ptrace_reparented(struct task_struct *child)
86{
87 return !same_thread_group(child->real_parent, child->parent);
88}
89
90static inline void ptrace_unlink(struct task_struct *child)
91{
92 if (unlikely(child->ptrace))
93 __ptrace_unlink(child);
94}
95
96int 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);
100
101/**
102 * 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/**
120 * 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/**
134 * ptrace_event - possibly stop for a ptrace event notification
135 * @event: %PTRACE_EVENT_* value to report
136 * @message: value for %PTRACE_GETEVENTMSG to return
137 *
138 * Check whether @event is enabled and, if so, report @event and @message
139 * to the ptrace parent.
140 *
141 * Called without locks.
142 */
143static inline void ptrace_event(int event, unsigned long message)
144{
145 if (unlikely(ptrace_event_enabled(current, event))) {
146 current->ptrace_message = message;
147 ptrace_notify((event << 8) | SIGTRAP);
148 } else if (event == PTRACE_EVENT_EXEC) {
149 /* legacy EXEC report via SIGTRAP */
150 if ((current->ptrace & (PT_PTRACED|PT_SEIZED)) == PT_PTRACED)
151 send_sig(SIGTRAP, current, 0);
152 }
153}
154
155/**
156 * 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/**
187 * 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);
200 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);
207
208 if (child->ptrace & PT_SEIZED)
209 task_set_jobctl_pending(child, JOBCTL_TRAP_STOP);
210 else
211 sigaddset(&child->pending.signal, SIGSTOP);
212
213 set_tsk_thread_flag(child, TIF_SIGPENDING);
214 }
215}
216
217/**
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
230#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
245#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
254/*
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
280 * next single instruction executes. If arch_has_block_step() is defined,
281 * this must clear the effects of user_enable_block_step() too.
282 */
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 *
292 * 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.
296 */
297static inline void user_disable_single_step(struct task_struct *task)
298{
299}
300#else
301extern void user_enable_single_step(struct task_struct *);
302extern void user_disable_single_step(struct task_struct *);
303#endif /* arch_has_single_step */
304
305#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 */
315#define arch_has_block_step() (0)
316
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}
330#else
331extern void user_enable_block_step(struct task_struct *);
332#endif /* arch_has_block_step */
333
334#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
346#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.
360 *
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.
363 */
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
384#ifndef current_pt_regs
385#define current_pt_regs() task_pt_regs(current)
386#endif
387
388#ifndef ptrace_signal_deliver
389#define ptrace_signal_deliver() ((void)0)
390#endif
391
392/*
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
401#ifndef current_user_stack_pointer
402#define current_user_stack_pointer() user_stack_pointer(current_pt_regs())
403#endif
404
405extern 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
409#endif