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 <uapi/linux/ptrace.h>
13 * The owner ship rules for task->ptrace which holds the ptrace
14 * flags is simple. When a task is running it owns it's task->ptrace
15 * flags. When the a task is stopped the ptracer owns task->ptrace.
18 #define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */
19 #define PT_PTRACED 0x00000001
20 #define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */
21 #define PT_PTRACE_CAP 0x00000004 /* ptracer can follow suid-exec */
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_check_attach(struct task_struct *task, bool ignore_state);
49 extern int ptrace_request(struct task_struct *child, long request,
50 unsigned long addr, unsigned long data);
51 extern void ptrace_notify(int exit_code);
52 extern void __ptrace_link(struct task_struct *child,
53 struct task_struct *new_parent);
54 extern void __ptrace_unlink(struct task_struct *child);
55 extern void exit_ptrace(struct task_struct *tracer);
56 #define PTRACE_MODE_READ 0x01
57 #define PTRACE_MODE_ATTACH 0x02
58 #define PTRACE_MODE_NOAUDIT 0x04
59 /* Returns true on success, false on denial. */
60 extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
62 static inline int ptrace_reparented(struct task_struct *child)
64 return !same_thread_group(child->real_parent, child->parent);
67 static inline void ptrace_unlink(struct task_struct *child)
69 if (unlikely(child->ptrace))
70 __ptrace_unlink(child);
73 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
75 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
79 * ptrace_parent - return the task that is tracing the given task
80 * @task: task to consider
82 * Returns %NULL if no one is tracing @task, or the &struct task_struct
83 * pointer to its tracer.
85 * Must called under rcu_read_lock(). The pointer returned might be kept
86 * live only by RCU. During exec, this may be called with task_lock() held
87 * on @task, still held from when check_unsafe_exec() was called.
89 static inline struct task_struct *ptrace_parent(struct task_struct *task)
91 if (unlikely(task->ptrace))
92 return rcu_dereference(task->parent);
97 * ptrace_event_enabled - test whether a ptrace event is enabled
98 * @task: ptracee of interest
99 * @event: %PTRACE_EVENT_* to test
101 * Test whether @event is enabled for ptracee @task.
103 * Returns %true if @event is enabled, %false otherwise.
105 static inline bool ptrace_event_enabled(struct task_struct *task, int event)
107 return task->ptrace & PT_EVENT_FLAG(event);
111 * ptrace_event - possibly stop for a ptrace event notification
112 * @event: %PTRACE_EVENT_* value to report
113 * @message: value for %PTRACE_GETEVENTMSG to return
115 * Check whether @event is enabled and, if so, report @event and @message
116 * to the ptrace parent.
118 * Called without locks.
120 static inline void ptrace_event(int event, unsigned long message)
122 if (unlikely(ptrace_event_enabled(current, event))) {
123 current->ptrace_message = message;
124 ptrace_notify((event << 8) | SIGTRAP);
125 } else if (event == PTRACE_EVENT_EXEC) {
126 /* legacy EXEC report via SIGTRAP */
127 if ((current->ptrace & (PT_PTRACED|PT_SEIZED)) == PT_PTRACED)
128 send_sig(SIGTRAP, current, 0);
133 * ptrace_init_task - initialize ptrace state for a new child
134 * @child: new child task
135 * @ptrace: true if child should be ptrace'd by parent's tracer
137 * This is called immediately after adding @child to its parent's children
138 * list. @ptrace is false in the normal case, and true to ptrace @child.
140 * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
142 static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
144 INIT_LIST_HEAD(&child->ptrace_entry);
145 INIT_LIST_HEAD(&child->ptraced);
146 #ifdef CONFIG_HAVE_HW_BREAKPOINT
147 atomic_set(&child->ptrace_bp_refcnt, 1);
151 child->parent = child->real_parent;
153 if (unlikely(ptrace) && current->ptrace) {
154 child->ptrace = current->ptrace;
155 __ptrace_link(child, current->parent);
157 if (child->ptrace & PT_SEIZED)
158 task_set_jobctl_pending(child, JOBCTL_TRAP_STOP);
160 sigaddset(&child->pending.signal, SIGSTOP);
162 set_tsk_thread_flag(child, TIF_SIGPENDING);
167 * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
168 * @task: task in %EXIT_DEAD state
170 * Called with write_lock(&tasklist_lock) held.
172 static inline void ptrace_release_task(struct task_struct *task)
174 BUG_ON(!list_empty(&task->ptraced));
176 BUG_ON(!list_empty(&task->ptrace_entry));
179 #ifndef force_successful_syscall_return
181 * System call handlers that, upon successful completion, need to return a
182 * negative value should call force_successful_syscall_return() right before
183 * returning. On architectures where the syscall convention provides for a
184 * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
185 * others), this macro can be used to ensure that the error flag will not get
186 * set. On architectures which do not support a separate error flag, the macro
187 * is a no-op and the spurious error condition needs to be filtered out by some
188 * other means (e.g., in user-level, by passing an extra argument to the
189 * syscall handler, or something along those lines).
191 #define force_successful_syscall_return() do { } while (0)
194 #ifndef is_syscall_success
196 * On most systems we can tell if a syscall is a success based on if the retval
197 * is an error value. On some systems like ia64 and powerpc they have different
198 * indicators of success/failure and must define their own.
200 #define is_syscall_success(regs) (!IS_ERR_VALUE((unsigned long)(regs_return_value(regs))))
204 * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
206 * These do-nothing inlines are used when the arch does not
207 * implement single-step. The kerneldoc comments are here
208 * to document the interface for all arch definitions.
211 #ifndef arch_has_single_step
213 * arch_has_single_step - does this CPU support user-mode single-step?
215 * If this is defined, then there must be function declarations or
216 * inlines for user_enable_single_step() and user_disable_single_step().
217 * arch_has_single_step() should evaluate to nonzero iff the machine
218 * supports instruction single-step for user mode.
219 * It can be a constant or it can test a CPU feature bit.
221 #define arch_has_single_step() (0)
224 * user_enable_single_step - single-step in user-mode task
225 * @task: either current or a task stopped in %TASK_TRACED
227 * This can only be called when arch_has_single_step() has returned nonzero.
228 * Set @task so that when it returns to user mode, it will trap after the
229 * next single instruction executes. If arch_has_block_step() is defined,
230 * this must clear the effects of user_enable_block_step() too.
232 static inline void user_enable_single_step(struct task_struct *task)
234 BUG(); /* This can never be called. */
238 * user_disable_single_step - cancel user-mode single-step
239 * @task: either current or a task stopped in %TASK_TRACED
241 * Clear @task of the effects of user_enable_single_step() and
242 * user_enable_block_step(). This can be called whether or not either
243 * of those was ever called on @task, and even if arch_has_single_step()
246 static inline void user_disable_single_step(struct task_struct *task)
250 extern void user_enable_single_step(struct task_struct *);
251 extern void user_disable_single_step(struct task_struct *);
252 #endif /* arch_has_single_step */
254 #ifndef arch_has_block_step
256 * arch_has_block_step - does this CPU support user-mode block-step?
258 * If this is defined, then there must be a function declaration or inline
259 * for user_enable_block_step(), and arch_has_single_step() must be defined
260 * too. arch_has_block_step() should evaluate to nonzero iff the machine
261 * supports step-until-branch for user mode. It can be a constant or it
262 * can test a CPU feature bit.
264 #define arch_has_block_step() (0)
267 * user_enable_block_step - step until branch in user-mode task
268 * @task: either current or a task stopped in %TASK_TRACED
270 * This can only be called when arch_has_block_step() has returned nonzero,
271 * and will never be called when single-instruction stepping is being used.
272 * Set @task so that when it returns to user mode, it will trap after the
273 * next branch or trap taken.
275 static inline void user_enable_block_step(struct task_struct *task)
277 BUG(); /* This can never be called. */
280 extern void user_enable_block_step(struct task_struct *);
281 #endif /* arch_has_block_step */
283 #ifdef ARCH_HAS_USER_SINGLE_STEP_INFO
284 extern void user_single_step_siginfo(struct task_struct *tsk,
285 struct pt_regs *regs, siginfo_t *info);
287 static inline void user_single_step_siginfo(struct task_struct *tsk,
288 struct pt_regs *regs, siginfo_t *info)
290 memset(info, 0, sizeof(*info));
291 info->si_signo = SIGTRAP;
295 #ifndef arch_ptrace_stop_needed
297 * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
298 * @code: current->exit_code value ptrace will stop with
299 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
301 * This is called with the siglock held, to decide whether or not it's
302 * necessary to release the siglock and call arch_ptrace_stop() with the
303 * same @code and @info arguments. It can be defined to a constant if
304 * arch_ptrace_stop() is never required, or always is. On machines where
305 * this makes sense, it should be defined to a quick test to optimize out
306 * calling arch_ptrace_stop() when it would be superfluous. For example,
307 * if the thread has not been back to user mode since the last stop, the
308 * thread state might indicate that nothing needs to be done.
310 #define arch_ptrace_stop_needed(code, info) (0)
313 #ifndef arch_ptrace_stop
315 * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
316 * @code: current->exit_code value ptrace will stop with
317 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
319 * This is called with no locks held when arch_ptrace_stop_needed() has
320 * just returned nonzero. It is allowed to block, e.g. for user memory
321 * access. The arch can have machine-specific work to be done before
322 * ptrace stops. On ia64, register backing store gets written back to user
323 * memory here. Since this can be costly (requires dropping the siglock),
324 * we only do it when the arch requires it for this particular stop, as
325 * indicated by arch_ptrace_stop_needed().
327 #define arch_ptrace_stop(code, info) do { } while (0)
330 #ifndef current_pt_regs
331 #define current_pt_regs() task_pt_regs(current)
334 #ifndef ptrace_signal_deliver
335 #define ptrace_signal_deliver() ((void)0)
339 * unlike current_pt_regs(), this one is equal to task_pt_regs(current)
340 * on *all* architectures; the only reason to have a per-arch definition
343 #ifndef signal_pt_regs
344 #define signal_pt_regs() task_pt_regs(current)
347 #ifndef current_user_stack_pointer
348 #define current_user_stack_pointer() user_stack_pointer(current_pt_regs())
351 extern int task_current_syscall(struct task_struct *target, long *callno,
352 unsigned long args[6], unsigned int maxargs,
353 unsigned long *sp, unsigned long *pc);
355 #ifdef CONFIG_HAVE_HW_BREAKPOINT
356 extern int ptrace_get_breakpoints(struct task_struct *tsk);
357 extern void ptrace_put_breakpoints(struct task_struct *tsk);
359 static inline void ptrace_put_breakpoints(struct task_struct *tsk) { }
360 #endif /* CONFIG_HAVE_HW_BREAKPOINT */