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, int write);
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)
40 /* single stepping state bits (used on ARM and PA-RISC) */
41 #define PT_SINGLESTEP_BIT 31
42 #define PT_SINGLESTEP (1<<PT_SINGLESTEP_BIT)
43 #define PT_BLOCKSTEP_BIT 30
44 #define PT_BLOCKSTEP (1<<PT_BLOCKSTEP_BIT)
46 extern long arch_ptrace(struct task_struct *child, long request,
47 unsigned long addr, unsigned long data);
48 extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
49 extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
50 extern void ptrace_disable(struct task_struct *);
51 extern int ptrace_request(struct task_struct *child, long request,
52 unsigned long addr, unsigned long data);
53 extern void ptrace_notify(int exit_code);
54 extern void __ptrace_link(struct task_struct *child,
55 struct task_struct *new_parent,
56 const struct cred *ptracer_cred);
57 extern void __ptrace_unlink(struct task_struct *child);
58 extern void exit_ptrace(struct task_struct *tracer);
59 #define PTRACE_MODE_READ 0x01
60 #define PTRACE_MODE_ATTACH 0x02
61 #define PTRACE_MODE_NOAUDIT 0x04
62 #define PTRACE_MODE_FSCREDS 0x08
63 #define PTRACE_MODE_REALCREDS 0x10
64 #define PTRACE_MODE_SCHED 0x20
65 #define PTRACE_MODE_IBPB 0x40
67 /* shorthands for READ/ATTACH and FSCREDS/REALCREDS combinations */
68 #define PTRACE_MODE_READ_FSCREDS (PTRACE_MODE_READ | PTRACE_MODE_FSCREDS)
69 #define PTRACE_MODE_READ_REALCREDS (PTRACE_MODE_READ | PTRACE_MODE_REALCREDS)
70 #define PTRACE_MODE_ATTACH_FSCREDS (PTRACE_MODE_ATTACH | PTRACE_MODE_FSCREDS)
71 #define PTRACE_MODE_ATTACH_REALCREDS (PTRACE_MODE_ATTACH | PTRACE_MODE_REALCREDS)
72 #define PTRACE_MODE_SPEC_IBPB (PTRACE_MODE_ATTACH_REALCREDS | PTRACE_MODE_IBPB)
75 * ptrace_may_access - check whether the caller is permitted to access
78 * @mode: selects type of access and caller credentials
80 * Returns true on success, false on denial.
82 * One of the flags PTRACE_MODE_FSCREDS and PTRACE_MODE_REALCREDS must
83 * be set in @mode to specify whether the access was requested through
84 * a filesystem syscall (should use effective capabilities and fsuid
85 * of the caller) or through an explicit syscall such as
86 * process_vm_writev or ptrace (and should use the real credentials).
88 extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
91 * ptrace_may_access - check whether the caller is permitted to access
94 * @mode: selects type of access and caller credentials
96 * Returns true on success, false on denial.
98 * Similar to ptrace_may_access(). Only to be called from context switch
99 * code. Does not call into audit and the regular LSM hooks due to locking
102 extern bool ptrace_may_access_sched(struct task_struct *task, unsigned int mode);
104 static inline int ptrace_reparented(struct task_struct *child)
106 return !same_thread_group(child->real_parent, child->parent);
109 static inline void ptrace_unlink(struct task_struct *child)
111 if (unlikely(child->ptrace))
112 __ptrace_unlink(child);
115 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
117 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
121 * ptrace_parent - return the task that is tracing the given task
122 * @task: task to consider
124 * Returns %NULL if no one is tracing @task, or the &struct task_struct
125 * pointer to its tracer.
127 * Must called under rcu_read_lock(). The pointer returned might be kept
128 * live only by RCU. During exec, this may be called with task_lock() held
129 * on @task, still held from when check_unsafe_exec() was called.
131 static inline struct task_struct *ptrace_parent(struct task_struct *task)
133 if (unlikely(task->ptrace))
134 return rcu_dereference(task->parent);
139 * ptrace_event_enabled - test whether a ptrace event is enabled
140 * @task: ptracee of interest
141 * @event: %PTRACE_EVENT_* to test
143 * Test whether @event is enabled for ptracee @task.
145 * Returns %true if @event is enabled, %false otherwise.
147 static inline bool ptrace_event_enabled(struct task_struct *task, int event)
149 return task->ptrace & PT_EVENT_FLAG(event);
153 * ptrace_event - possibly stop for a ptrace event notification
154 * @event: %PTRACE_EVENT_* value to report
155 * @message: value for %PTRACE_GETEVENTMSG to return
157 * Check whether @event is enabled and, if so, report @event and @message
158 * to the ptrace parent.
160 * Called without locks.
162 static inline void ptrace_event(int event, unsigned long message)
164 if (unlikely(ptrace_event_enabled(current, event))) {
165 current->ptrace_message = message;
166 ptrace_notify((event << 8) | SIGTRAP);
167 } else if (event == PTRACE_EVENT_EXEC) {
168 /* legacy EXEC report via SIGTRAP */
169 if ((current->ptrace & (PT_PTRACED|PT_SEIZED)) == PT_PTRACED)
170 send_sig(SIGTRAP, current, 0);
175 * ptrace_event_pid - possibly stop for a ptrace event notification
176 * @event: %PTRACE_EVENT_* value to report
177 * @pid: process identifier for %PTRACE_GETEVENTMSG to return
179 * Check whether @event is enabled and, if so, report @event and @pid
180 * to the ptrace parent. @pid is reported as the pid_t seen from the
181 * the ptrace parent's pid namespace.
183 * Called without locks.
185 static inline void ptrace_event_pid(int event, struct pid *pid)
188 * FIXME: There's a potential race if a ptracer in a different pid
189 * namespace than parent attaches between computing message below and
190 * when we acquire tasklist_lock in ptrace_stop(). If this happens,
191 * the ptracer will get a bogus pid from PTRACE_GETEVENTMSG.
193 unsigned long message = 0;
194 struct pid_namespace *ns;
197 ns = task_active_pid_ns(rcu_dereference(current->parent));
199 message = pid_nr_ns(pid, ns);
202 ptrace_event(event, message);
206 * ptrace_init_task - initialize ptrace state for a new child
207 * @child: new child task
208 * @ptrace: true if child should be ptrace'd by parent's tracer
210 * This is called immediately after adding @child to its parent's children
211 * list. @ptrace is false in the normal case, and true to ptrace @child.
213 * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
215 static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
217 INIT_LIST_HEAD(&child->ptrace_entry);
218 INIT_LIST_HEAD(&child->ptraced);
221 child->parent = child->real_parent;
223 if (unlikely(ptrace) && current->ptrace) {
224 child->ptrace = current->ptrace;
225 __ptrace_link(child, current->parent, current->ptracer_cred);
227 if (child->ptrace & PT_SEIZED)
228 task_set_jobctl_pending(child, JOBCTL_TRAP_STOP);
230 sigaddset(&child->pending.signal, SIGSTOP);
232 set_tsk_thread_flag(child, TIF_SIGPENDING);
235 child->ptracer_cred = NULL;
239 * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
240 * @task: task in %EXIT_DEAD state
242 * Called with write_lock(&tasklist_lock) held.
244 static inline void ptrace_release_task(struct task_struct *task)
246 BUG_ON(!list_empty(&task->ptraced));
248 BUG_ON(!list_empty(&task->ptrace_entry));
251 #ifndef force_successful_syscall_return
253 * System call handlers that, upon successful completion, need to return a
254 * negative value should call force_successful_syscall_return() right before
255 * returning. On architectures where the syscall convention provides for a
256 * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
257 * others), this macro can be used to ensure that the error flag will not get
258 * set. On architectures which do not support a separate error flag, the macro
259 * is a no-op and the spurious error condition needs to be filtered out by some
260 * other means (e.g., in user-level, by passing an extra argument to the
261 * syscall handler, or something along those lines).
263 #define force_successful_syscall_return() do { } while (0)
266 #ifndef is_syscall_success
268 * On most systems we can tell if a syscall is a success based on if the retval
269 * is an error value. On some systems like ia64 and powerpc they have different
270 * indicators of success/failure and must define their own.
272 #define is_syscall_success(regs) (!IS_ERR_VALUE((unsigned long)(regs_return_value(regs))))
276 * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
278 * These do-nothing inlines are used when the arch does not
279 * implement single-step. The kerneldoc comments are here
280 * to document the interface for all arch definitions.
283 #ifndef arch_has_single_step
285 * arch_has_single_step - does this CPU support user-mode single-step?
287 * If this is defined, then there must be function declarations or
288 * inlines for user_enable_single_step() and user_disable_single_step().
289 * arch_has_single_step() should evaluate to nonzero iff the machine
290 * supports instruction single-step for user mode.
291 * It can be a constant or it can test a CPU feature bit.
293 #define arch_has_single_step() (0)
296 * user_enable_single_step - single-step in user-mode task
297 * @task: either current or a task stopped in %TASK_TRACED
299 * This can only be called when arch_has_single_step() has returned nonzero.
300 * Set @task so that when it returns to user mode, it will trap after the
301 * next single instruction executes. If arch_has_block_step() is defined,
302 * this must clear the effects of user_enable_block_step() too.
304 static inline void user_enable_single_step(struct task_struct *task)
306 BUG(); /* This can never be called. */
310 * user_disable_single_step - cancel user-mode single-step
311 * @task: either current or a task stopped in %TASK_TRACED
313 * Clear @task of the effects of user_enable_single_step() and
314 * user_enable_block_step(). This can be called whether or not either
315 * of those was ever called on @task, and even if arch_has_single_step()
318 static inline void user_disable_single_step(struct task_struct *task)
322 extern void user_enable_single_step(struct task_struct *);
323 extern void user_disable_single_step(struct task_struct *);
324 #endif /* arch_has_single_step */
326 #ifndef arch_has_block_step
328 * arch_has_block_step - does this CPU support user-mode block-step?
330 * If this is defined, then there must be a function declaration or inline
331 * for user_enable_block_step(), and arch_has_single_step() must be defined
332 * too. arch_has_block_step() should evaluate to nonzero iff the machine
333 * supports step-until-branch for user mode. It can be a constant or it
334 * can test a CPU feature bit.
336 #define arch_has_block_step() (0)
339 * user_enable_block_step - step until branch in user-mode task
340 * @task: either current or a task stopped in %TASK_TRACED
342 * This can only be called when arch_has_block_step() has returned nonzero,
343 * and will never be called when single-instruction stepping is being used.
344 * Set @task so that when it returns to user mode, it will trap after the
345 * next branch or trap taken.
347 static inline void user_enable_block_step(struct task_struct *task)
349 BUG(); /* This can never be called. */
352 extern void user_enable_block_step(struct task_struct *);
353 #endif /* arch_has_block_step */
355 #ifdef ARCH_HAS_USER_SINGLE_STEP_INFO
356 extern void user_single_step_siginfo(struct task_struct *tsk,
357 struct pt_regs *regs, siginfo_t *info);
359 static inline void user_single_step_siginfo(struct task_struct *tsk,
360 struct pt_regs *regs, siginfo_t *info)
362 memset(info, 0, sizeof(*info));
363 info->si_signo = SIGTRAP;
367 #ifndef arch_ptrace_stop_needed
369 * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
370 * @code: current->exit_code value ptrace will stop with
371 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
373 * This is called with the siglock held, to decide whether or not it's
374 * necessary to release the siglock and call arch_ptrace_stop() with the
375 * same @code and @info arguments. It can be defined to a constant if
376 * arch_ptrace_stop() is never required, or always is. On machines where
377 * this makes sense, it should be defined to a quick test to optimize out
378 * calling arch_ptrace_stop() when it would be superfluous. For example,
379 * if the thread has not been back to user mode since the last stop, the
380 * thread state might indicate that nothing needs to be done.
382 * This is guaranteed to be invoked once before a task stops for ptrace and
383 * may include arch-specific operations necessary prior to a ptrace stop.
385 #define arch_ptrace_stop_needed(code, info) (0)
388 #ifndef arch_ptrace_stop
390 * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
391 * @code: current->exit_code value ptrace will stop with
392 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
394 * This is called with no locks held when arch_ptrace_stop_needed() has
395 * just returned nonzero. It is allowed to block, e.g. for user memory
396 * access. The arch can have machine-specific work to be done before
397 * ptrace stops. On ia64, register backing store gets written back to user
398 * memory here. Since this can be costly (requires dropping the siglock),
399 * we only do it when the arch requires it for this particular stop, as
400 * indicated by arch_ptrace_stop_needed().
402 #define arch_ptrace_stop(code, info) do { } while (0)
405 #ifndef current_pt_regs
406 #define current_pt_regs() task_pt_regs(current)
409 #ifndef ptrace_signal_deliver
410 #define ptrace_signal_deliver() ((void)0)
414 * unlike current_pt_regs(), this one is equal to task_pt_regs(current)
415 * on *all* architectures; the only reason to have a per-arch definition
418 #ifndef signal_pt_regs
419 #define signal_pt_regs() task_pt_regs(current)
422 #ifndef current_user_stack_pointer
423 #define current_user_stack_pointer() user_stack_pointer(current_pt_regs())
426 extern int task_current_syscall(struct task_struct *target, long *callno,
427 unsigned long args[6], unsigned int maxargs,
428 unsigned long *sp, unsigned long *pc);