include/linux/ptrace.h

   1 #ifndef _LINUX_PTRACE_H
   2 #define _LINUX_PTRACE_H
   3 /* ptrace.h */
   4 /* structs and defines to help the user use the ptrace system call. */
   5
   6 /* has the defines to get at the registers. */
   7
   8 #define PTRACE_TRACEME             0
   9 #define PTRACE_PEEKTEXT            1
  10 #define PTRACE_PEEKDATA            2
  11 #define PTRACE_PEEKUSR             3
  12 #define PTRACE_POKETEXT            4
  13 #define PTRACE_POKEDATA            5
  14 #define PTRACE_POKEUSR             6
  15 #define PTRACE_CONT                7
  16 #define PTRACE_KILL                8
  17 #define PTRACE_SINGLESTEP          9
  18
  19 #define PTRACE_ATTACH             16
  20 #define PTRACE_DETACH             17
  21
  22 #define PTRACE_SYSCALL            24
  23
  24 /* 0x4200-0x4300 are reserved for architecture-independent additions.  */
  25 #define PTRACE_SETOPTIONS       0x4200
  26 #define PTRACE_GETEVENTMSG      0x4201
  27 #define PTRACE_GETSIGINFO       0x4202
  28 #define PTRACE_SETSIGINFO       0x4203
  29
  30 /*
  31  * Generic ptrace interface that exports the architecture specific regsets
  32  * using the corresponding NT_* types (which are also used in the core dump).
  33  * Please note that the NT_PRSTATUS note type in a core dump contains a full
  34  * 'struct elf_prstatus'. But the user_regset for NT_PRSTATUS contains just the
  35  * elf_gregset_t that is the pr_reg field of 'struct elf_prstatus'. For all the
  36  * other user_regset flavors, the user_regset layout and the ELF core dump note
  37  * payload are exactly the same layout.
  38  *
  39  * This interface usage is as follows:
  40  *      struct iovec iov = { buf, len};
  41  *
  42  *      ret = ptrace(PTRACE_GETREGSET/PTRACE_SETREGSET, pid, NT_XXX_TYPE, &iov);
  43  *
  44  * On the successful completion, iov.len will be updated by the kernel,
  45  * specifying how much the kernel has written/read to/from the user's iov.buf.
  46  */
  47 #define PTRACE_GETREGSET        0x4204
  48 #define PTRACE_SETREGSET        0x4205
  49
  50 #define PTRACE_SEIZE            0x4206
  51 #define PTRACE_INTERRUPT        0x4207
  52 #define PTRACE_LISTEN           0x4208
  53
  54 /* flags in @data for PTRACE_SEIZE */
  55 #define PTRACE_SEIZE_DEVEL      0x80000000 /* temp flag for development */
  56
  57 /* options set using PTRACE_SETOPTIONS */
  58 #define PTRACE_O_TRACESYSGOOD   0x00000001
  59 #define PTRACE_O_TRACEFORK      0x00000002
  60 #define PTRACE_O_TRACEVFORK     0x00000004
  61 #define PTRACE_O_TRACECLONE     0x00000008
  62 #define PTRACE_O_TRACEEXEC      0x00000010
  63 #define PTRACE_O_TRACEVFORKDONE 0x00000020
  64 #define PTRACE_O_TRACEEXIT      0x00000040
  65
  66 #define PTRACE_O_MASK           0x0000007f
  67
  68 /* Wait extended result codes for the above trace options.  */
  69 #define PTRACE_EVENT_FORK       1
  70 #define PTRACE_EVENT_VFORK      2
  71 #define PTRACE_EVENT_CLONE      3
  72 #define PTRACE_EVENT_EXEC       4
  73 #define PTRACE_EVENT_VFORK_DONE 5
  74 #define PTRACE_EVENT_EXIT       6
  75 #define PTRACE_EVENT_STOP       7
  76
  77 #include <asm/ptrace.h>
  78
  79 #ifdef __KERNEL__
  80 /*
  81  * Ptrace flags
  82  *
  83  * The owner ship rules for task->ptrace which holds the ptrace
  84  * flags is simple.  When a task is running it owns it's task->ptrace
  85  * flags.  When the a task is stopped the ptracer owns task->ptrace.
  86  */
  87
  88 #define PT_SEIZED       0x00010000      /* SEIZE used, enable new behavior */
  89 #define PT_PTRACED      0x00000001
  90 #define PT_DTRACE       0x00000002      /* delayed trace (used on m68k, i386) */
  91 #define PT_TRACESYSGOOD 0x00000004
  92 #define PT_PTRACE_CAP   0x00000008      /* ptracer can follow suid-exec */
  93
  94 /* PT_TRACE_* event enable flags */
  95 #define PT_EVENT_FLAG_SHIFT     4
  96 #define PT_EVENT_FLAG(event)    (1 << (PT_EVENT_FLAG_SHIFT + (event) - 1))
  97
  98 #define PT_TRACE_FORK           PT_EVENT_FLAG(PTRACE_EVENT_FORK)
  99 #define PT_TRACE_VFORK          PT_EVENT_FLAG(PTRACE_EVENT_VFORK)
 100 #define PT_TRACE_CLONE          PT_EVENT_FLAG(PTRACE_EVENT_CLONE)
 101 #define PT_TRACE_EXEC           PT_EVENT_FLAG(PTRACE_EVENT_EXEC)
 102 #define PT_TRACE_VFORK_DONE     PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE)
 103 #define PT_TRACE_EXIT           PT_EVENT_FLAG(PTRACE_EVENT_EXIT)
 104
 105 #define PT_TRACE_MASK   0x000003f4
 106
 107 /* single stepping state bits (used on ARM and PA-RISC) */
 108 #define PT_SINGLESTEP_BIT       31
 109 #define PT_SINGLESTEP           (1<<PT_SINGLESTEP_BIT)
 110 #define PT_BLOCKSTEP_BIT        30
 111 #define PT_BLOCKSTEP            (1<<PT_BLOCKSTEP_BIT)
 112
 113 #include <linux/compiler.h>             /* For unlikely.  */
 114 #include <linux/sched.h>                /* For struct task_struct.  */
 115
 116
 117 extern long arch_ptrace(struct task_struct *child, long request,
 118                         unsigned long addr, unsigned long data);
 119 extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
 120 extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
 121 extern void ptrace_disable(struct task_struct *);
 122 extern int ptrace_check_attach(struct task_struct *task, bool ignore_state);
 123 extern int ptrace_request(struct task_struct *child, long request,
 124                           unsigned long addr, unsigned long data);
 125 extern void ptrace_notify(int exit_code);
 126 extern void __ptrace_link(struct task_struct *child,
 127                           struct task_struct *new_parent);
 128 extern void __ptrace_unlink(struct task_struct *child);
 129 extern void exit_ptrace(struct task_struct *tracer);
 130 #define PTRACE_MODE_READ   1
 131 #define PTRACE_MODE_ATTACH 2
 132 /* Returns 0 on success, -errno on denial. */
 133 extern int __ptrace_may_access(struct task_struct *task, unsigned int mode);
 134 /* Returns true on success, false on denial. */
 135 extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
 136
 137 static inline int ptrace_reparented(struct task_struct *child)
 138 {
 139         return !same_thread_group(child->real_parent, child->parent);
 140 }
 141
 142 static inline void ptrace_unlink(struct task_struct *child)
 143 {
 144         if (unlikely(child->ptrace))
 145                 __ptrace_unlink(child);
 146 }
 147
 148 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
 149                             unsigned long data);
 150 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
 151                             unsigned long data);
 152
 153 /**
 154  * ptrace_parent - return the task that is tracing the given task
 155  * @task: task to consider
 156  *
 157  * Returns %NULL if no one is tracing @task, or the &struct task_struct
 158  * pointer to its tracer.
 159  *
 160  * Must called under rcu_read_lock().  The pointer returned might be kept
 161  * live only by RCU.  During exec, this may be called with task_lock() held
 162  * on @task, still held from when check_unsafe_exec() was called.
 163  */
 164 static inline struct task_struct *ptrace_parent(struct task_struct *task)
 165 {
 166         if (unlikely(task->ptrace))
 167                 return rcu_dereference(task->parent);
 168         return NULL;
 169 }
 170
 171 /**
 172  * ptrace_event_enabled - test whether a ptrace event is enabled
 173  * @task: ptracee of interest
 174  * @event: %PTRACE_EVENT_* to test
 175  *
 176  * Test whether @event is enabled for ptracee @task.
 177  *
 178  * Returns %true if @event is enabled, %false otherwise.
 179  */
 180 static inline bool ptrace_event_enabled(struct task_struct *task, int event)
 181 {
 182         return task->ptrace & PT_EVENT_FLAG(event);
 183 }
 184
 185 /**
 186  * ptrace_event - possibly stop for a ptrace event notification
 187  * @event:      %PTRACE_EVENT_* value to report
 188  * @message:    value for %PTRACE_GETEVENTMSG to return
 189  *
 190  * Check whether @event is enabled and, if so, report @event and @message
 191  * to the ptrace parent.
 192  *
 193  * Called without locks.
 194  */
 195 static inline void ptrace_event(int event, unsigned long message)
 196 {
 197         if (unlikely(ptrace_event_enabled(current, event))) {
 198                 current->ptrace_message = message;
 199                 ptrace_notify((event << 8) | SIGTRAP);
 200         } else if (event == PTRACE_EVENT_EXEC && unlikely(current->ptrace)) {
 201                 /* legacy EXEC report via SIGTRAP */
 202                 send_sig(SIGTRAP, current, 0);
 203         }
 204 }
 205
 206 /**
 207  * ptrace_init_task - initialize ptrace state for a new child
 208  * @child:              new child task
 209  * @ptrace:             true if child should be ptrace'd by parent's tracer
 210  *
 211  * This is called immediately after adding @child to its parent's children
 212  * list.  @ptrace is false in the normal case, and true to ptrace @child.
 213  *
 214  * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
 215  */
 216 static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
 217 {
 218         INIT_LIST_HEAD(&child->ptrace_entry);
 219         INIT_LIST_HEAD(&child->ptraced);
 220 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 221         atomic_set(&child->ptrace_bp_refcnt, 1);
 222 #endif
 223         child->jobctl = 0;
 224         child->ptrace = 0;
 225         child->parent = child->real_parent;
 226
 227         if (unlikely(ptrace) && current->ptrace) {
 228                 child->ptrace = current->ptrace;
 229                 __ptrace_link(child, current->parent);
 230
 231                 if (child->ptrace & PT_SEIZED)
 232                         task_set_jobctl_pending(child, JOBCTL_TRAP_STOP);
 233                 else
 234                         sigaddset(&child->pending.signal, SIGSTOP);
 235
 236                 set_tsk_thread_flag(child, TIF_SIGPENDING);
 237         }
 238 }
 239
 240 /**
 241  * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
 242  * @task:       task in %EXIT_DEAD state
 243  *
 244  * Called with write_lock(&tasklist_lock) held.
 245  */
 246 static inline void ptrace_release_task(struct task_struct *task)
 247 {
 248         BUG_ON(!list_empty(&task->ptraced));
 249         ptrace_unlink(task);
 250         BUG_ON(!list_empty(&task->ptrace_entry));
 251 }
 252
 253 #ifndef force_successful_syscall_return
 254 /*
 255  * System call handlers that, upon successful completion, need to return a
 256  * negative value should call force_successful_syscall_return() right before
 257  * returning.  On architectures where the syscall convention provides for a
 258  * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
 259  * others), this macro can be used to ensure that the error flag will not get
 260  * set.  On architectures which do not support a separate error flag, the macro
 261  * is a no-op and the spurious error condition needs to be filtered out by some
 262  * other means (e.g., in user-level, by passing an extra argument to the
 263  * syscall handler, or something along those lines).
 264  */
 265 #define force_successful_syscall_return() do { } while (0)
 266 #endif
 267
 268 /*
 269  * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
 270  *
 271  * These do-nothing inlines are used when the arch does not
 272  * implement single-step.  The kerneldoc comments are here
 273  * to document the interface for all arch definitions.
 274  */
 275
 276 #ifndef arch_has_single_step
 277 /**
 278  * arch_has_single_step - does this CPU support user-mode single-step?
 279  *
 280  * If this is defined, then there must be function declarations or
 281  * inlines for user_enable_single_step() and user_disable_single_step().
 282  * arch_has_single_step() should evaluate to nonzero iff the machine
 283  * supports instruction single-step for user mode.
 284  * It can be a constant or it can test a CPU feature bit.
 285  */
 286 #define arch_has_single_step()          (0)
 287
 288 /**
 289  * user_enable_single_step - single-step in user-mode task
 290  * @task: either current or a task stopped in %TASK_TRACED
 291  *
 292  * This can only be called when arch_has_single_step() has returned nonzero.
 293  * Set @task so that when it returns to user mode, it will trap after the
 294  * next single instruction executes.  If arch_has_block_step() is defined,
 295  * this must clear the effects of user_enable_block_step() too.
 296  */
 297 static inline void user_enable_single_step(struct task_struct *task)
 298 {
 299         BUG();                  /* This can never be called.  */
 300 }
 301
 302 /**
 303  * user_disable_single_step - cancel user-mode single-step
 304  * @task: either current or a task stopped in %TASK_TRACED
 305  *
 306  * Clear @task of the effects of user_enable_single_step() and
 307  * user_enable_block_step().  This can be called whether or not either
 308  * of those was ever called on @task, and even if arch_has_single_step()
 309  * returned zero.
 310  */
 311 static inline void user_disable_single_step(struct task_struct *task)
 312 {
 313 }
 314 #else
 315 extern void user_enable_single_step(struct task_struct *);
 316 extern void user_disable_single_step(struct task_struct *);
 317 #endif  /* arch_has_single_step */
 318
 319 #ifndef arch_has_block_step
 320 /**
 321  * arch_has_block_step - does this CPU support user-mode block-step?
 322  *
 323  * If this is defined, then there must be a function declaration or inline
 324  * for user_enable_block_step(), and arch_has_single_step() must be defined
 325  * too.  arch_has_block_step() should evaluate to nonzero iff the machine
 326  * supports step-until-branch for user mode.  It can be a constant or it
 327  * can test a CPU feature bit.
 328  */
 329 #define arch_has_block_step()           (0)
 330
 331 /**
 332  * user_enable_block_step - step until branch in user-mode task
 333  * @task: either current or a task stopped in %TASK_TRACED
 334  *
 335  * This can only be called when arch_has_block_step() has returned nonzero,
 336  * and will never be called when single-instruction stepping is being used.
 337  * Set @task so that when it returns to user mode, it will trap after the
 338  * next branch or trap taken.
 339  */
 340 static inline void user_enable_block_step(struct task_struct *task)
 341 {
 342         BUG();                  /* This can never be called.  */
 343 }
 344 #else
 345 extern void user_enable_block_step(struct task_struct *);
 346 #endif  /* arch_has_block_step */
 347
 348 #ifdef ARCH_HAS_USER_SINGLE_STEP_INFO
 349 extern void user_single_step_siginfo(struct task_struct *tsk,
 350                                 struct pt_regs *regs, siginfo_t *info);
 351 #else
 352 static inline void user_single_step_siginfo(struct task_struct *tsk,
 353                                 struct pt_regs *regs, siginfo_t *info)
 354 {
 355         memset(info, 0, sizeof(*info));
 356         info->si_signo = SIGTRAP;
 357 }
 358 #endif
 359
 360 #ifndef arch_ptrace_stop_needed
 361 /**
 362  * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
 363  * @code:       current->exit_code value ptrace will stop with
 364  * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
 365  *
 366  * This is called with the siglock held, to decide whether or not it's
 367  * necessary to release the siglock and call arch_ptrace_stop() with the
 368  * same @code and @info arguments.  It can be defined to a constant if
 369  * arch_ptrace_stop() is never required, or always is.  On machines where
 370  * this makes sense, it should be defined to a quick test to optimize out
 371  * calling arch_ptrace_stop() when it would be superfluous.  For example,
 372  * if the thread has not been back to user mode since the last stop, the
 373  * thread state might indicate that nothing needs to be done.
 374  */
 375 #define arch_ptrace_stop_needed(code, info)     (0)
 376 #endif
 377
 378 #ifndef arch_ptrace_stop
 379 /**
 380  * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
 381  * @code:       current->exit_code value ptrace will stop with
 382  * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
 383  *
 384  * This is called with no locks held when arch_ptrace_stop_needed() has
 385  * just returned nonzero.  It is allowed to block, e.g. for user memory
 386  * access.  The arch can have machine-specific work to be done before
 387  * ptrace stops.  On ia64, register backing store gets written back to user
 388  * memory here.  Since this can be costly (requires dropping the siglock),
 389  * we only do it when the arch requires it for this particular stop, as
 390  * indicated by arch_ptrace_stop_needed().
 391  */
 392 #define arch_ptrace_stop(code, info)            do { } while (0)
 393 #endif
 394
 395 extern int task_current_syscall(struct task_struct *target, long *callno,
 396                                 unsigned long args[6], unsigned int maxargs,
 397                                 unsigned long *sp, unsigned long *pc);
 398
 399 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 400 extern int ptrace_get_breakpoints(struct task_struct *tsk);
 401 extern void ptrace_put_breakpoints(struct task_struct *tsk);
 402 #else
 403 static inline void ptrace_put_breakpoints(struct task_struct *tsk) { }
 404 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 405
 406 #endif /* __KERNEL */
 407
 408 #endif