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>
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.
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) */
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)
35 #define PT_EXITKILL (PTRACE_O_EXITKILL << PT_OPT_FLAG_SHIFT)
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)
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 const struct cred *ptracer_cred);
54 extern void __ptrace_unlink(struct task_struct *child);
55 extern void exit_ptrace(struct task_struct *tracer, struct list_head *dead);
56 #define PTRACE_MODE_READ 0x01
57 #define PTRACE_MODE_ATTACH 0x02
58 #define PTRACE_MODE_NOAUDIT 0x04
59 #define PTRACE_MODE_FSCREDS 0x08
60 #define PTRACE_MODE_REALCREDS 0x10
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)
69 * ptrace_may_access - check whether the caller is permitted to access
72 * @mode: selects type of access and caller credentials
74 * Returns true on success, false on denial.
76 * One of the flags PTRACE_MODE_FSCREDS and PTRACE_MODE_REALCREDS must
77 * be set in @mode to specify whether the access was requested through
78 * a filesystem syscall (should use effective capabilities and fsuid
79 * of the caller) or through an explicit syscall such as
80 * process_vm_writev or ptrace (and should use the real credentials).
82 extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
84 static inline int ptrace_reparented(struct task_struct *child)
86 return !same_thread_group(child->real_parent, child->parent);
89 static inline void ptrace_unlink(struct task_struct *child)
91 if (unlikely(child->ptrace))
92 __ptrace_unlink(child);
95 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
97 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
101 * ptrace_parent - return the task that is tracing the given task
102 * @task: task to consider
104 * Returns %NULL if no one is tracing @task, or the &struct task_struct
105 * pointer to its tracer.
107 * Must called under rcu_read_lock(). The pointer returned might be kept
108 * live only by RCU. During exec, this may be called with task_lock() held
109 * on @task, still held from when check_unsafe_exec() was called.
111 static inline struct task_struct *ptrace_parent(struct task_struct *task)
113 if (unlikely(task->ptrace))
114 return rcu_dereference(task->parent);
119 * ptrace_event_enabled - test whether a ptrace event is enabled
120 * @task: ptracee of interest
121 * @event: %PTRACE_EVENT_* to test
123 * Test whether @event is enabled for ptracee @task.
125 * Returns %true if @event is enabled, %false otherwise.
127 static inline bool ptrace_event_enabled(struct task_struct *task, int event)
129 return task->ptrace & PT_EVENT_FLAG(event);
133 * ptrace_event - possibly stop for a ptrace event notification
134 * @event: %PTRACE_EVENT_* value to report
135 * @message: value for %PTRACE_GETEVENTMSG to return
137 * Check whether @event is enabled and, if so, report @event and @message
138 * to the ptrace parent.
140 * Called without locks.
142 static inline void ptrace_event(int event, unsigned long message)
144 if (unlikely(ptrace_event_enabled(current, event))) {
145 current->ptrace_message = message;
146 ptrace_notify((event << 8) | SIGTRAP);
147 } else if (event == PTRACE_EVENT_EXEC) {
148 /* legacy EXEC report via SIGTRAP */
149 if ((current->ptrace & (PT_PTRACED|PT_SEIZED)) == PT_PTRACED)
150 send_sig(SIGTRAP, current, 0);
155 * ptrace_event_pid - possibly stop for a ptrace event notification
156 * @event: %PTRACE_EVENT_* value to report
157 * @pid: process identifier for %PTRACE_GETEVENTMSG to return
159 * Check whether @event is enabled and, if so, report @event and @pid
160 * to the ptrace parent. @pid is reported as the pid_t seen from the
161 * the ptrace parent's pid namespace.
163 * Called without locks.
165 static inline void ptrace_event_pid(int event, struct pid *pid)
168 * FIXME: There's a potential race if a ptracer in a different pid
169 * namespace than parent attaches between computing message below and
170 * when we acquire tasklist_lock in ptrace_stop(). If this happens,
171 * the ptracer will get a bogus pid from PTRACE_GETEVENTMSG.
173 unsigned long message = 0;
174 struct pid_namespace *ns;
177 ns = task_active_pid_ns(rcu_dereference(current->parent));
179 message = pid_nr_ns(pid, ns);
182 ptrace_event(event, message);
186 * ptrace_init_task - initialize ptrace state for a new child
187 * @child: new child task
188 * @ptrace: true if child should be ptrace'd by parent's tracer
190 * This is called immediately after adding @child to its parent's children
191 * list. @ptrace is false in the normal case, and true to ptrace @child.
193 * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
195 static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
197 INIT_LIST_HEAD(&child->ptrace_entry);
198 INIT_LIST_HEAD(&child->ptraced);
201 child->parent = child->real_parent;
203 if (unlikely(ptrace) && current->ptrace) {
204 child->ptrace = current->ptrace;
205 __ptrace_link(child, current->parent, current->ptracer_cred);
207 if (child->ptrace & PT_SEIZED)
208 task_set_jobctl_pending(child, JOBCTL_TRAP_STOP);
210 sigaddset(&child->pending.signal, SIGSTOP);
212 set_tsk_thread_flag(child, TIF_SIGPENDING);
215 child->ptracer_cred = NULL;
219 * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
220 * @task: task in %EXIT_DEAD state
222 * Called with write_lock(&tasklist_lock) held.
224 static inline void ptrace_release_task(struct task_struct *task)
226 BUG_ON(!list_empty(&task->ptraced));
228 BUG_ON(!list_empty(&task->ptrace_entry));
231 #ifndef force_successful_syscall_return
233 * System call handlers that, upon successful completion, need to return a
234 * negative value should call force_successful_syscall_return() right before
235 * returning. On architectures where the syscall convention provides for a
236 * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
237 * others), this macro can be used to ensure that the error flag will not get
238 * set. On architectures which do not support a separate error flag, the macro
239 * is a no-op and the spurious error condition needs to be filtered out by some
240 * other means (e.g., in user-level, by passing an extra argument to the
241 * syscall handler, or something along those lines).
243 #define force_successful_syscall_return() do { } while (0)
246 #ifndef is_syscall_success
248 * On most systems we can tell if a syscall is a success based on if the retval
249 * is an error value. On some systems like ia64 and powerpc they have different
250 * indicators of success/failure and must define their own.
252 #define is_syscall_success(regs) (!IS_ERR_VALUE((unsigned long)(regs_return_value(regs))))
256 * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
258 * These do-nothing inlines are used when the arch does not
259 * implement single-step. The kerneldoc comments are here
260 * to document the interface for all arch definitions.
263 #ifndef arch_has_single_step
265 * arch_has_single_step - does this CPU support user-mode single-step?
267 * If this is defined, then there must be function declarations or
268 * inlines for user_enable_single_step() and user_disable_single_step().
269 * arch_has_single_step() should evaluate to nonzero iff the machine
270 * supports instruction single-step for user mode.
271 * It can be a constant or it can test a CPU feature bit.
273 #define arch_has_single_step() (0)
276 * user_enable_single_step - single-step in user-mode task
277 * @task: either current or a task stopped in %TASK_TRACED
279 * This can only be called when arch_has_single_step() has returned nonzero.
280 * Set @task so that when it returns to user mode, it will trap after the
281 * next single instruction executes. If arch_has_block_step() is defined,
282 * this must clear the effects of user_enable_block_step() too.
284 static inline void user_enable_single_step(struct task_struct *task)
286 BUG(); /* This can never be called. */
290 * user_disable_single_step - cancel user-mode single-step
291 * @task: either current or a task stopped in %TASK_TRACED
293 * Clear @task of the effects of user_enable_single_step() and
294 * user_enable_block_step(). This can be called whether or not either
295 * of those was ever called on @task, and even if arch_has_single_step()
298 static inline void user_disable_single_step(struct task_struct *task)
302 extern void user_enable_single_step(struct task_struct *);
303 extern void user_disable_single_step(struct task_struct *);
304 #endif /* arch_has_single_step */
306 #ifndef arch_has_block_step
308 * arch_has_block_step - does this CPU support user-mode block-step?
310 * If this is defined, then there must be a function declaration or inline
311 * for user_enable_block_step(), and arch_has_single_step() must be defined
312 * too. arch_has_block_step() should evaluate to nonzero iff the machine
313 * supports step-until-branch for user mode. It can be a constant or it
314 * can test a CPU feature bit.
316 #define arch_has_block_step() (0)
319 * user_enable_block_step - step until branch in user-mode task
320 * @task: either current or a task stopped in %TASK_TRACED
322 * This can only be called when arch_has_block_step() has returned nonzero,
323 * and will never be called when single-instruction stepping is being used.
324 * Set @task so that when it returns to user mode, it will trap after the
325 * next branch or trap taken.
327 static inline void user_enable_block_step(struct task_struct *task)
329 BUG(); /* This can never be called. */
332 extern void user_enable_block_step(struct task_struct *);
333 #endif /* arch_has_block_step */
335 #ifdef ARCH_HAS_USER_SINGLE_STEP_INFO
336 extern void user_single_step_siginfo(struct task_struct *tsk,
337 struct pt_regs *regs, siginfo_t *info);
339 static inline void user_single_step_siginfo(struct task_struct *tsk,
340 struct pt_regs *regs, siginfo_t *info)
342 memset(info, 0, sizeof(*info));
343 info->si_signo = SIGTRAP;
347 #ifndef arch_ptrace_stop_needed
349 * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
350 * @code: current->exit_code value ptrace will stop with
351 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
353 * This is called with the siglock held, to decide whether or not it's
354 * necessary to release the siglock and call arch_ptrace_stop() with the
355 * same @code and @info arguments. It can be defined to a constant if
356 * arch_ptrace_stop() is never required, or always is. On machines where
357 * this makes sense, it should be defined to a quick test to optimize out
358 * calling arch_ptrace_stop() when it would be superfluous. For example,
359 * if the thread has not been back to user mode since the last stop, the
360 * thread state might indicate that nothing needs to be done.
362 * This is guaranteed to be invoked once before a task stops for ptrace and
363 * may include arch-specific operations necessary prior to a ptrace stop.
365 #define arch_ptrace_stop_needed(code, info) (0)
368 #ifndef arch_ptrace_stop
370 * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
371 * @code: current->exit_code value ptrace will stop with
372 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
374 * This is called with no locks held when arch_ptrace_stop_needed() has
375 * just returned nonzero. It is allowed to block, e.g. for user memory
376 * access. The arch can have machine-specific work to be done before
377 * ptrace stops. On ia64, register backing store gets written back to user
378 * memory here. Since this can be costly (requires dropping the siglock),
379 * we only do it when the arch requires it for this particular stop, as
380 * indicated by arch_ptrace_stop_needed().
382 #define arch_ptrace_stop(code, info) do { } while (0)
385 #ifndef current_pt_regs
386 #define current_pt_regs() task_pt_regs(current)
389 #ifndef ptrace_signal_deliver
390 #define ptrace_signal_deliver() ((void)0)
394 * unlike current_pt_regs(), this one is equal to task_pt_regs(current)
395 * on *all* architectures; the only reason to have a per-arch definition
398 #ifndef signal_pt_regs
399 #define signal_pt_regs() task_pt_regs(current)
402 #ifndef current_user_stack_pointer
403 #define current_user_stack_pointer() user_stack_pointer(current_pt_regs())
406 extern int task_current_syscall(struct task_struct *target, long *callno,
407 unsigned long args[6], unsigned int maxargs,
408 unsigned long *sp, unsigned long *pc);