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 #include <linux/err.h>                  /* for IS_ERR_VALUE */
 116
 117
 118 extern long arch_ptrace(struct task_struct *child, long request,
 119                         unsigned long addr, unsigned long data);
 120 extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
 121 extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
 122 extern void ptrace_disable(struct task_struct *);
 123 extern int ptrace_check_attach(struct task_struct *task, bool ignore_state);
 124 extern int ptrace_request(struct task_struct *child, long request,
 125                           unsigned long addr, unsigned long data);
 126 extern void ptrace_notify(int exit_code);
 127 extern void __ptrace_link(struct task_struct *child,
 128                           struct task_struct *new_parent);
 129 extern void __ptrace_unlink(struct task_struct *child);
 130 extern void exit_ptrace(struct task_struct *tracer);
 131 #define PTRACE_MODE_READ        0x01
 132 #define PTRACE_MODE_ATTACH      0x02
 133 #define PTRACE_MODE_NOAUDIT     0x04
 134 /* Returns 0 on success, -errno on denial. */
 135 extern int __ptrace_may_access(struct task_struct *task, unsigned int mode);
 136 /* Returns true on success, false on denial. */
 137 extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
 138
 139 static inline int ptrace_reparented(struct task_struct *child)
 140 {
 141         return !same_thread_group(child->real_parent, child->parent);
 142 }
 143
 144 static inline void ptrace_unlink(struct task_struct *child)
 145 {
 146         if (unlikely(child->ptrace))
 147                 __ptrace_unlink(child);
 148 }
 149
 150 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
 151                             unsigned long data);
 152 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
 153                             unsigned long data);
 154
 155 /**
 156  * ptrace_parent - return the task that is tracing the given task
 157  * @task: task to consider
 158  *
 159  * Returns %NULL if no one is tracing @task, or the &struct task_struct
 160  * pointer to its tracer.
 161  *
 162  * Must called under rcu_read_lock().  The pointer returned might be kept
 163  * live only by RCU.  During exec, this may be called with task_lock() held
 164  * on @task, still held from when check_unsafe_exec() was called.
 165  */
 166 static inline struct task_struct *ptrace_parent(struct task_struct *task)
 167 {
 168         if (unlikely(task->ptrace))
 169                 return rcu_dereference(task->parent);
 170         return NULL;
 171 }
 172
 173 /**
 174  * ptrace_event_enabled - test whether a ptrace event is enabled
 175  * @task: ptracee of interest
 176  * @event: %PTRACE_EVENT_* to test
 177  *
 178  * Test whether @event is enabled for ptracee @task.
 179  *
 180  * Returns %true if @event is enabled, %false otherwise.
 181  */
 182 static inline bool ptrace_event_enabled(struct task_struct *task, int event)
 183 {
 184         return task->ptrace & PT_EVENT_FLAG(event);
 185 }
 186
 187 /**
 188  * ptrace_event - possibly stop for a ptrace event notification
 189  * @event:      %PTRACE_EVENT_* value to report
 190  * @message:    value for %PTRACE_GETEVENTMSG to return
 191  *
 192  * Check whether @event is enabled and, if so, report @event and @message
 193  * to the ptrace parent.
 194  *
 195  * Called without locks.
 196  */
 197 static inline void ptrace_event(int event, unsigned long message)
 198 {
 199         if (unlikely(ptrace_event_enabled(current, event))) {
 200                 current->ptrace_message = message;
 201                 ptrace_notify((event << 8) | SIGTRAP);
 202         } else if (event == PTRACE_EVENT_EXEC && unlikely(current->ptrace)) {
 203                 /* legacy EXEC report via SIGTRAP */
 204                 send_sig(SIGTRAP, current, 0);
 205         }
 206 }
 207
 208 /**
 209  * ptrace_init_task - initialize ptrace state for a new child
 210  * @child:              new child task
 211  * @ptrace:             true if child should be ptrace'd by parent's tracer
 212  *
 213  * This is called immediately after adding @child to its parent's children
 214  * list.  @ptrace is false in the normal case, and true to ptrace @child.
 215  *
 216  * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
 217  */
 218 static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
 219 {
 220         INIT_LIST_HEAD(&child->ptrace_entry);
 221         INIT_LIST_HEAD(&child->ptraced);
 222 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 223         atomic_set(&child->ptrace_bp_refcnt, 1);
 224 #endif
 225         child->jobctl = 0;
 226         child->ptrace = 0;
 227         child->parent = child->real_parent;
 228
 229         if (unlikely(ptrace) && current->ptrace) {
 230                 child->ptrace = current->ptrace;
 231                 __ptrace_link(child, current->parent);
 232
 233                 if (child->ptrace & PT_SEIZED)
 234                         task_set_jobctl_pending(child, JOBCTL_TRAP_STOP);
 235                 else
 236                         sigaddset(&child->pending.signal, SIGSTOP);
 237
 238                 set_tsk_thread_flag(child, TIF_SIGPENDING);
 239         }
 240 }
 241
 242 /**
 243  * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
 244  * @task:       task in %EXIT_DEAD state
 245  *
 246  * Called with write_lock(&tasklist_lock) held.
 247  */
 248 static inline void ptrace_release_task(struct task_struct *task)
 249 {
 250         BUG_ON(!list_empty(&task->ptraced));
 251         ptrace_unlink(task);
 252         BUG_ON(!list_empty(&task->ptrace_entry));
 253 }
 254
 255 #ifndef force_successful_syscall_return
 256 /*
 257  * System call handlers that, upon successful completion, need to return a
 258  * negative value should call force_successful_syscall_return() right before
 259  * returning.  On architectures where the syscall convention provides for a
 260  * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
 261  * others), this macro can be used to ensure that the error flag will not get
 262  * set.  On architectures which do not support a separate error flag, the macro
 263  * is a no-op and the spurious error condition needs to be filtered out by some
 264  * other means (e.g., in user-level, by passing an extra argument to the
 265  * syscall handler, or something along those lines).
 266  */
 267 #define force_successful_syscall_return() do { } while (0)
 268 #endif
 269
 270 #ifndef is_syscall_success
 271 /*
 272  * On most systems we can tell if a syscall is a success based on if the retval
 273  * is an error value.  On some systems like ia64 and powerpc they have different
 274  * indicators of success/failure and must define their own.
 275  */
 276 #define is_syscall_success(regs) (!IS_ERR_VALUE((unsigned long)(regs_return_value(regs))))
 277 #endif
 278
 279 /*
 280  * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
 281  *
 282  * These do-nothing inlines are used when the arch does not
 283  * implement single-step.  The kerneldoc comments are here
 284  * to document the interface for all arch definitions.
 285  */
 286
 287 #ifndef arch_has_single_step
 288 /**
 289  * arch_has_single_step - does this CPU support user-mode single-step?
 290  *
 291  * If this is defined, then there must be function declarations or
 292  * inlines for user_enable_single_step() and user_disable_single_step().
 293  * arch_has_single_step() should evaluate to nonzero iff the machine
 294  * supports instruction single-step for user mode.
 295  * It can be a constant or it can test a CPU feature bit.
 296  */
 297 #define arch_has_single_step()          (0)
 298
 299 /**
 300  * user_enable_single_step - single-step in user-mode task
 301  * @task: either current or a task stopped in %TASK_TRACED
 302  *
 303  * This can only be called when arch_has_single_step() has returned nonzero.
 304  * Set @task so that when it returns to user mode, it will trap after the
 305  * next single instruction executes.  If arch_has_block_step() is defined,
 306  * this must clear the effects of user_enable_block_step() too.
 307  */
 308 static inline void user_enable_single_step(struct task_struct *task)
 309 {
 310         BUG();                  /* This can never be called.  */
 311 }
 312
 313 /**
 314  * user_disable_single_step - cancel user-mode single-step
 315  * @task: either current or a task stopped in %TASK_TRACED
 316  *
 317  * Clear @task of the effects of user_enable_single_step() and
 318  * user_enable_block_step().  This can be called whether or not either
 319  * of those was ever called on @task, and even if arch_has_single_step()
 320  * returned zero.
 321  */
 322 static inline void user_disable_single_step(struct task_struct *task)
 323 {
 324 }
 325 #else
 326 extern void user_enable_single_step(struct task_struct *);
 327 extern void user_disable_single_step(struct task_struct *);
 328 #endif  /* arch_has_single_step */
 329
 330 #ifndef arch_has_block_step
 331 /**
 332  * arch_has_block_step - does this CPU support user-mode block-step?
 333  *
 334  * If this is defined, then there must be a function declaration or inline
 335  * for user_enable_block_step(), and arch_has_single_step() must be defined
 336  * too.  arch_has_block_step() should evaluate to nonzero iff the machine
 337  * supports step-until-branch for user mode.  It can be a constant or it
 338  * can test a CPU feature bit.
 339  */
 340 #define arch_has_block_step()           (0)
 341
 342 /**
 343  * user_enable_block_step - step until branch in user-mode task
 344  * @task: either current or a task stopped in %TASK_TRACED
 345  *
 346  * This can only be called when arch_has_block_step() has returned nonzero,
 347  * and will never be called when single-instruction stepping is being used.
 348  * Set @task so that when it returns to user mode, it will trap after the
 349  * next branch or trap taken.
 350  */
 351 static inline void user_enable_block_step(struct task_struct *task)
 352 {
 353         BUG();                  /* This can never be called.  */
 354 }
 355 #else
 356 extern void user_enable_block_step(struct task_struct *);
 357 #endif  /* arch_has_block_step */
 358
 359 #ifdef ARCH_HAS_USER_SINGLE_STEP_INFO
 360 extern void user_single_step_siginfo(struct task_struct *tsk,
 361                                 struct pt_regs *regs, siginfo_t *info);
 362 #else
 363 static inline void user_single_step_siginfo(struct task_struct *tsk,
 364                                 struct pt_regs *regs, siginfo_t *info)
 365 {
 366         memset(info, 0, sizeof(*info));
 367         info->si_signo = SIGTRAP;
 368 }
 369 #endif
 370
 371 #ifndef arch_ptrace_stop_needed
 372 /**
 373  * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
 374  * @code:       current->exit_code value ptrace will stop with
 375  * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
 376  *
 377  * This is called with the siglock held, to decide whether or not it's
 378  * necessary to release the siglock and call arch_ptrace_stop() with the
 379  * same @code and @info arguments.  It can be defined to a constant if
 380  * arch_ptrace_stop() is never required, or always is.  On machines where
 381  * this makes sense, it should be defined to a quick test to optimize out
 382  * calling arch_ptrace_stop() when it would be superfluous.  For example,
 383  * if the thread has not been back to user mode since the last stop, the
 384  * thread state might indicate that nothing needs to be done.
 385  */
 386 #define arch_ptrace_stop_needed(code, info)     (0)
 387 #endif
 388
 389 #ifndef arch_ptrace_stop
 390 /**
 391  * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
 392  * @code:       current->exit_code value ptrace will stop with
 393  * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
 394  *
 395  * This is called with no locks held when arch_ptrace_stop_needed() has
 396  * just returned nonzero.  It is allowed to block, e.g. for user memory
 397  * access.  The arch can have machine-specific work to be done before
 398  * ptrace stops.  On ia64, register backing store gets written back to user
 399  * memory here.  Since this can be costly (requires dropping the siglock),
 400  * we only do it when the arch requires it for this particular stop, as
 401  * indicated by arch_ptrace_stop_needed().
 402  */
 403 #define arch_ptrace_stop(code, info)            do { } while (0)
 404 #endif
 405
 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);
 409
 410 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 411 extern int ptrace_get_breakpoints(struct task_struct *tsk);
 412 extern void ptrace_put_breakpoints(struct task_struct *tsk);
 413 #else
 414 static inline void ptrace_put_breakpoints(struct task_struct *tsk) { }
 415 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 416
 417 #endif /* __KERNEL */
 418
 419 #endif