1 #ifndef _LINUX_PTRACE_H
2 #define _LINUX_PTRACE_H
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>
11 extern int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
12 void *buf, int len, unsigned int gup_flags);
17 * The owner ship rules for task->ptrace which holds the ptrace
18 * flags is simple. When a task is running it owns it's task->ptrace
19 * flags. When the a task is stopped the ptracer owns task->ptrace.
22 #define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */
23 #define PT_PTRACED 0x00000001
24 #define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */
26 #define PT_OPT_FLAG_SHIFT 3
27 /* PT_TRACE_* event enable flags */
28 #define PT_EVENT_FLAG(event) (1 << (PT_OPT_FLAG_SHIFT + (event)))
29 #define PT_TRACESYSGOOD PT_EVENT_FLAG(0)
30 #define PT_TRACE_FORK PT_EVENT_FLAG(PTRACE_EVENT_FORK)
31 #define PT_TRACE_VFORK PT_EVENT_FLAG(PTRACE_EVENT_VFORK)
32 #define PT_TRACE_CLONE PT_EVENT_FLAG(PTRACE_EVENT_CLONE)
33 #define PT_TRACE_EXEC PT_EVENT_FLAG(PTRACE_EVENT_EXEC)
34 #define PT_TRACE_VFORK_DONE PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE)
35 #define PT_TRACE_EXIT PT_EVENT_FLAG(PTRACE_EVENT_EXIT)
36 #define PT_TRACE_SECCOMP PT_EVENT_FLAG(PTRACE_EVENT_SECCOMP)
38 #define PT_EXITKILL (PTRACE_O_EXITKILL << PT_OPT_FLAG_SHIFT)
39 #define PT_SUSPEND_SECCOMP (PTRACE_O_SUSPEND_SECCOMP << PT_OPT_FLAG_SHIFT)
41 extern long arch_ptrace(struct task_struct *child, long request,
42 unsigned long addr, unsigned long data);
43 extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
44 extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
45 extern void ptrace_disable(struct task_struct *);
46 extern int ptrace_request(struct task_struct *child, long request,
47 unsigned long addr, unsigned long data);
48 extern void ptrace_notify(int exit_code);
49 extern void __ptrace_link(struct task_struct *child,
50 struct task_struct *new_parent,
51 const struct cred *ptracer_cred);
52 extern void __ptrace_unlink(struct task_struct *child);
53 extern void exit_ptrace(struct task_struct *tracer, struct list_head *dead);
54 #define PTRACE_MODE_READ 0x01
55 #define PTRACE_MODE_ATTACH 0x02
56 #define PTRACE_MODE_NOAUDIT 0x04
57 #define PTRACE_MODE_FSCREDS 0x08
58 #define PTRACE_MODE_REALCREDS 0x10
59 #define PTRACE_MODE_SCHED 0x20
60 #define PTRACE_MODE_IBPB 0x40
62 /* shorthands for READ/ATTACH and FSCREDS/REALCREDS combinations */
63 #define PTRACE_MODE_READ_FSCREDS (PTRACE_MODE_READ | PTRACE_MODE_FSCREDS)
64 #define PTRACE_MODE_READ_REALCREDS (PTRACE_MODE_READ | PTRACE_MODE_REALCREDS)
65 #define PTRACE_MODE_ATTACH_FSCREDS (PTRACE_MODE_ATTACH | PTRACE_MODE_FSCREDS)
66 #define PTRACE_MODE_ATTACH_REALCREDS (PTRACE_MODE_ATTACH | PTRACE_MODE_REALCREDS)
67 #define PTRACE_MODE_SPEC_IBPB (PTRACE_MODE_ATTACH_REALCREDS | PTRACE_MODE_IBPB)
70 * ptrace_may_access - check whether the caller is permitted to access
73 * @mode: selects type of access and caller credentials
75 * Returns true on success, false on denial.
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).
83 extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
86 * ptrace_may_access - check whether the caller is permitted to access
89 * @mode: selects type of access and caller credentials
91 * Returns true on success, false on denial.
93 * Similar to ptrace_may_access(). Only to be called from context switch
94 * code. Does not call into audit and the regular LSM hooks due to locking
97 extern bool ptrace_may_access_sched(struct task_struct *task, unsigned int mode);
99 static inline int ptrace_reparented(struct task_struct *child)
101 return !same_thread_group(child->real_parent, child->parent);
104 static inline void ptrace_unlink(struct task_struct *child)
106 if (unlikely(child->ptrace))
107 __ptrace_unlink(child);
110 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
112 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
116 * ptrace_parent - return the task that is tracing the given task
117 * @task: task to consider
119 * Returns %NULL if no one is tracing @task, or the &struct task_struct
120 * pointer to its tracer.
122 * Must called under rcu_read_lock(). The pointer returned might be kept
123 * live only by RCU. During exec, this may be called with task_lock() held
124 * on @task, still held from when check_unsafe_exec() was called.
126 static inline struct task_struct *ptrace_parent(struct task_struct *task)
128 if (unlikely(task->ptrace))
129 return rcu_dereference(task->parent);
134 * ptrace_event_enabled - test whether a ptrace event is enabled
135 * @task: ptracee of interest
136 * @event: %PTRACE_EVENT_* to test
138 * Test whether @event is enabled for ptracee @task.
140 * Returns %true if @event is enabled, %false otherwise.
142 static inline bool ptrace_event_enabled(struct task_struct *task, int event)
144 return task->ptrace & PT_EVENT_FLAG(event);
148 * ptrace_event - possibly stop for a ptrace event notification
149 * @event: %PTRACE_EVENT_* value to report
150 * @message: value for %PTRACE_GETEVENTMSG to return
152 * Check whether @event is enabled and, if so, report @event and @message
153 * to the ptrace parent.
155 * Called without locks.
157 static inline void ptrace_event(int event, unsigned long message)
159 if (unlikely(ptrace_event_enabled(current, event))) {
160 current->ptrace_message = message;
161 ptrace_notify((event << 8) | SIGTRAP);
162 } else if (event == PTRACE_EVENT_EXEC) {
163 /* legacy EXEC report via SIGTRAP */
164 if ((current->ptrace & (PT_PTRACED|PT_SEIZED)) == PT_PTRACED)
165 send_sig(SIGTRAP, current, 0);
170 * ptrace_event_pid - possibly stop for a ptrace event notification
171 * @event: %PTRACE_EVENT_* value to report
172 * @pid: process identifier for %PTRACE_GETEVENTMSG to return
174 * Check whether @event is enabled and, if so, report @event and @pid
175 * to the ptrace parent. @pid is reported as the pid_t seen from the
176 * the ptrace parent's pid namespace.
178 * Called without locks.
180 static inline void ptrace_event_pid(int event, struct pid *pid)
183 * FIXME: There's a potential race if a ptracer in a different pid
184 * namespace than parent attaches between computing message below and
185 * when we acquire tasklist_lock in ptrace_stop(). If this happens,
186 * the ptracer will get a bogus pid from PTRACE_GETEVENTMSG.
188 unsigned long message = 0;
189 struct pid_namespace *ns;
192 ns = task_active_pid_ns(rcu_dereference(current->parent));
194 message = pid_nr_ns(pid, ns);
197 ptrace_event(event, message);
201 * ptrace_init_task - initialize ptrace state for a new child
202 * @child: new child task
203 * @ptrace: true if child should be ptrace'd by parent's tracer
205 * This is called immediately after adding @child to its parent's children
206 * list. @ptrace is false in the normal case, and true to ptrace @child.
208 * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
210 static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
212 INIT_LIST_HEAD(&child->ptrace_entry);
213 INIT_LIST_HEAD(&child->ptraced);
216 child->parent = child->real_parent;
218 if (unlikely(ptrace) && current->ptrace) {
219 child->ptrace = current->ptrace;
220 __ptrace_link(child, current->parent, current->ptracer_cred);
222 if (child->ptrace & PT_SEIZED)
223 task_set_jobctl_pending(child, JOBCTL_TRAP_STOP);
225 sigaddset(&child->pending.signal, SIGSTOP);
227 set_tsk_thread_flag(child, TIF_SIGPENDING);
230 child->ptracer_cred = NULL;
234 * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
235 * @task: task in %EXIT_DEAD state
237 * Called with write_lock(&tasklist_lock) held.
239 static inline void ptrace_release_task(struct task_struct *task)
241 BUG_ON(!list_empty(&task->ptraced));
243 BUG_ON(!list_empty(&task->ptrace_entry));
246 #ifndef force_successful_syscall_return
248 * System call handlers that, upon successful completion, need to return a
249 * negative value should call force_successful_syscall_return() right before
250 * returning. On architectures where the syscall convention provides for a
251 * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
252 * others), this macro can be used to ensure that the error flag will not get
253 * set. On architectures which do not support a separate error flag, the macro
254 * is a no-op and the spurious error condition needs to be filtered out by some
255 * other means (e.g., in user-level, by passing an extra argument to the
256 * syscall handler, or something along those lines).
258 #define force_successful_syscall_return() do { } while (0)
261 #ifndef is_syscall_success
263 * On most systems we can tell if a syscall is a success based on if the retval
264 * is an error value. On some systems like ia64 and powerpc they have different
265 * indicators of success/failure and must define their own.
267 #define is_syscall_success(regs) (!IS_ERR_VALUE((unsigned long)(regs_return_value(regs))))
271 * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
273 * These do-nothing inlines are used when the arch does not
274 * implement single-step. The kerneldoc comments are here
275 * to document the interface for all arch definitions.
278 #ifndef arch_has_single_step
280 * arch_has_single_step - does this CPU support user-mode single-step?
282 * If this is defined, then there must be function declarations or
283 * inlines for user_enable_single_step() and user_disable_single_step().
284 * arch_has_single_step() should evaluate to nonzero iff the machine
285 * supports instruction single-step for user mode.
286 * It can be a constant or it can test a CPU feature bit.
288 #define arch_has_single_step() (0)
291 * user_enable_single_step - single-step in user-mode task
292 * @task: either current or a task stopped in %TASK_TRACED
294 * This can only be called when arch_has_single_step() has returned nonzero.
295 * Set @task so that when it returns to user mode, it will trap after the
296 * next single instruction executes. If arch_has_block_step() is defined,
297 * this must clear the effects of user_enable_block_step() too.
299 static inline void user_enable_single_step(struct task_struct *task)
301 BUG(); /* This can never be called. */
305 * user_disable_single_step - cancel user-mode single-step
306 * @task: either current or a task stopped in %TASK_TRACED
308 * Clear @task of the effects of user_enable_single_step() and
309 * user_enable_block_step(). This can be called whether or not either
310 * of those was ever called on @task, and even if arch_has_single_step()
313 static inline void user_disable_single_step(struct task_struct *task)
317 extern void user_enable_single_step(struct task_struct *);
318 extern void user_disable_single_step(struct task_struct *);
319 #endif /* arch_has_single_step */
321 #ifndef arch_has_block_step
323 * arch_has_block_step - does this CPU support user-mode block-step?
325 * If this is defined, then there must be a function declaration or inline
326 * for user_enable_block_step(), and arch_has_single_step() must be defined
327 * too. arch_has_block_step() should evaluate to nonzero iff the machine
328 * supports step-until-branch for user mode. It can be a constant or it
329 * can test a CPU feature bit.
331 #define arch_has_block_step() (0)
334 * user_enable_block_step - step until branch in user-mode task
335 * @task: either current or a task stopped in %TASK_TRACED
337 * This can only be called when arch_has_block_step() has returned nonzero,
338 * and will never be called when single-instruction stepping is being used.
339 * Set @task so that when it returns to user mode, it will trap after the
340 * next branch or trap taken.
342 static inline void user_enable_block_step(struct task_struct *task)
344 BUG(); /* This can never be called. */
347 extern void user_enable_block_step(struct task_struct *);
348 #endif /* arch_has_block_step */
350 #ifdef ARCH_HAS_USER_SINGLE_STEP_INFO
351 extern void user_single_step_siginfo(struct task_struct *tsk,
352 struct pt_regs *regs, siginfo_t *info);
354 static inline void user_single_step_siginfo(struct task_struct *tsk,
355 struct pt_regs *regs, siginfo_t *info)
357 memset(info, 0, sizeof(*info));
358 info->si_signo = SIGTRAP;
362 #ifndef arch_ptrace_stop_needed
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
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.
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.
380 #define arch_ptrace_stop_needed(code, info) (0)
383 #ifndef arch_ptrace_stop
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
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().
397 #define arch_ptrace_stop(code, info) do { } while (0)
400 #ifndef current_pt_regs
401 #define current_pt_regs() task_pt_regs(current)
404 #ifndef ptrace_signal_deliver
405 #define ptrace_signal_deliver() ((void)0)
409 * unlike current_pt_regs(), this one is equal to task_pt_regs(current)
410 * on *all* architectures; the only reason to have a per-arch definition
413 #ifndef signal_pt_regs
414 #define signal_pt_regs() task_pt_regs(current)
417 #ifndef current_user_stack_pointer
418 #define current_user_stack_pointer() user_stack_pointer(current_pt_regs())
421 extern int task_current_syscall(struct task_struct *target, long *callno,
422 unsigned long args[6], unsigned int maxargs,
423 unsigned long *sp, unsigned long *pc);