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 /* Wait extended result codes for the above trace options.  */
  55 #define PTRACE_EVENT_FORK       1
  56 #define PTRACE_EVENT_VFORK      2
  57 #define PTRACE_EVENT_CLONE      3
  58 #define PTRACE_EVENT_EXEC       4
  59 #define PTRACE_EVENT_VFORK_DONE 5
  60 #define PTRACE_EVENT_EXIT       6
  61 /* Extended result codes which enabled by means other than options.  */
  62 #define PTRACE_EVENT_STOP       128
  63
  64 /* Options set using PTRACE_SETOPTIONS or using PTRACE_SEIZE @data param */
  65 #define PTRACE_O_TRACESYSGOOD   1
  66 #define PTRACE_O_TRACEFORK      (1 << PTRACE_EVENT_FORK)
  67 #define PTRACE_O_TRACEVFORK     (1 << PTRACE_EVENT_VFORK)
  68 #define PTRACE_O_TRACECLONE     (1 << PTRACE_EVENT_CLONE)
  69 #define PTRACE_O_TRACEEXEC      (1 << PTRACE_EVENT_EXEC)
  70 #define PTRACE_O_TRACEVFORKDONE (1 << PTRACE_EVENT_VFORK_DONE)
  71 #define PTRACE_O_TRACEEXIT      (1 << PTRACE_EVENT_EXIT)
  72
  73 #define PTRACE_O_MASK           0x0000007f
  74
  75 #include <asm/ptrace.h>
  76
  77 #ifdef __KERNEL__
  78 /*
  79  * Ptrace flags
  80  *
  81  * The owner ship rules for task->ptrace which holds the ptrace
  82  * flags is simple.  When a task is running it owns it's task->ptrace
  83  * flags.  When the a task is stopped the ptracer owns task->ptrace.
  84  */
  85
  86 #define PT_SEIZED       0x00010000      /* SEIZE used, enable new behavior */
  87 #define PT_PTRACED      0x00000001
  88 #define PT_DTRACE       0x00000002      /* delayed trace (used on m68k, i386) */
  89 #define PT_PTRACE_CAP   0x00000004      /* ptracer can follow suid-exec */
  90
  91 #define PT_OPT_FLAG_SHIFT       3
  92 /* PT_TRACE_* event enable flags */
  93 #define PT_EVENT_FLAG(event)    (1 << (PT_OPT_FLAG_SHIFT + (event)))
  94 #define PT_TRACESYSGOOD         PT_EVENT_FLAG(0)
  95 #define PT_TRACE_FORK           PT_EVENT_FLAG(PTRACE_EVENT_FORK)
  96 #define PT_TRACE_VFORK          PT_EVENT_FLAG(PTRACE_EVENT_VFORK)
  97 #define PT_TRACE_CLONE          PT_EVENT_FLAG(PTRACE_EVENT_CLONE)
  98 #define PT_TRACE_EXEC           PT_EVENT_FLAG(PTRACE_EVENT_EXEC)
  99 #define PT_TRACE_VFORK_DONE     PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE)
 100 #define PT_TRACE_EXIT           PT_EVENT_FLAG(PTRACE_EVENT_EXIT)
 101
 102 /* single stepping state bits (used on ARM and PA-RISC) */
 103 #define PT_SINGLESTEP_BIT       31
 104 #define PT_SINGLESTEP           (1<<PT_SINGLESTEP_BIT)
 105 #define PT_BLOCKSTEP_BIT        30
 106 #define PT_BLOCKSTEP            (1<<PT_BLOCKSTEP_BIT)
 107
 108 #include <linux/compiler.h>             /* For unlikely.  */
 109 #include <linux/sched.h>                /* For struct task_struct.  */
 110 #include <linux/err.h>                  /* for IS_ERR_VALUE */
 111
 112
 113 extern long arch_ptrace(struct task_struct *child, long request,
 114                         unsigned long addr, unsigned long data);
 115 extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
 116 extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
 117 extern void ptrace_disable(struct task_struct *);
 118 extern int ptrace_check_attach(struct task_struct *task, bool ignore_state);
 119 extern int ptrace_request(struct task_struct *child, long request,
 120                           unsigned long addr, unsigned long data);
 121 extern void ptrace_notify(int exit_code);
 122 extern void __ptrace_link(struct task_struct *child,
 123                           struct task_struct *new_parent);
 124 extern void __ptrace_unlink(struct task_struct *child);
 125 extern void exit_ptrace(struct task_struct *tracer);
 126 #define PTRACE_MODE_READ        0x01
 127 #define PTRACE_MODE_ATTACH      0x02
 128 #define PTRACE_MODE_NOAUDIT     0x04
 129 /* Returns 0 on success, -errno on denial. */
 130 extern int __ptrace_may_access(struct task_struct *task, unsigned int mode);
 131 /* Returns true on success, false on denial. */
 132 extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
 133
 134 static inline int ptrace_reparented(struct task_struct *child)
 135 {
 136         return !same_thread_group(child->real_parent, child->parent);
 137 }
 138
 139 static inline void ptrace_unlink(struct task_struct *child)
 140 {
 141         if (unlikely(child->ptrace))
 142                 __ptrace_unlink(child);
 143 }
 144
 145 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
 146                             unsigned long data);
 147 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
 148                             unsigned long data);
 149
 150 /**
 151  * ptrace_parent - return the task that is tracing the given task
 152  * @task: task to consider
 153  *
 154  * Returns %NULL if no one is tracing @task, or the &struct task_struct
 155  * pointer to its tracer.
 156  *
 157  * Must called under rcu_read_lock().  The pointer returned might be kept
 158  * live only by RCU.  During exec, this may be called with task_lock() held
 159  * on @task, still held from when check_unsafe_exec() was called.
 160  */
 161 static inline struct task_struct *ptrace_parent(struct task_struct *task)
 162 {
 163         if (unlikely(task->ptrace))
 164                 return rcu_dereference(task->parent);
 165         return NULL;
 166 }
 167
 168 /**
 169  * ptrace_event_enabled - test whether a ptrace event is enabled
 170  * @task: ptracee of interest
 171  * @event: %PTRACE_EVENT_* to test
 172  *
 173  * Test whether @event is enabled for ptracee @task.
 174  *
 175  * Returns %true if @event is enabled, %false otherwise.
 176  */
 177 static inline bool ptrace_event_enabled(struct task_struct *task, int event)
 178 {
 179         return task->ptrace & PT_EVENT_FLAG(event);
 180 }
 181
 182 /**
 183  * ptrace_event - possibly stop for a ptrace event notification
 184  * @event:      %PTRACE_EVENT_* value to report
 185  * @message:    value for %PTRACE_GETEVENTMSG to return
 186  *
 187  * Check whether @event is enabled and, if so, report @event and @message
 188  * to the ptrace parent.
 189  *
 190  * Called without locks.
 191  */
 192 static inline void ptrace_event(int event, unsigned long message)
 193 {
 194         if (unlikely(ptrace_event_enabled(current, event))) {
 195                 current->ptrace_message = message;
 196                 ptrace_notify((event << 8) | SIGTRAP);
 197         } else if (event == PTRACE_EVENT_EXEC) {
 198                 /* legacy EXEC report via SIGTRAP */
 199                 if ((current->ptrace & (PT_PTRACED|PT_SEIZED)) == PT_PTRACED)
 200                         send_sig(SIGTRAP, current, 0);
 201         }
 202 }
 203
 204 /**
 205  * ptrace_init_task - initialize ptrace state for a new child
 206  * @child:              new child task
 207  * @ptrace:             true if child should be ptrace'd by parent's tracer
 208  *
 209  * This is called immediately after adding @child to its parent's children
 210  * list.  @ptrace is false in the normal case, and true to ptrace @child.
 211  *
 212  * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
 213  */
 214 static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
 215 {
 216         INIT_LIST_HEAD(&child->ptrace_entry);
 217         INIT_LIST_HEAD(&child->ptraced);
 218 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 219         atomic_set(&child->ptrace_bp_refcnt, 1);
 220 #endif
 221         child->jobctl = 0;
 222         child->ptrace = 0;
 223         child->parent = child->real_parent;
 224
 225         if (unlikely(ptrace) && current->ptrace) {
 226                 child->ptrace = current->ptrace;
 227                 __ptrace_link(child, current->parent);
 228
 229                 if (child->ptrace & PT_SEIZED)
 230                         task_set_jobctl_pending(child, JOBCTL_TRAP_STOP);
 231                 else
 232                         sigaddset(&child->pending.signal, SIGSTOP);
 233
 234                 set_tsk_thread_flag(child, TIF_SIGPENDING);
 235         }
 236 }
 237
 238 /**
 239  * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
 240  * @task:       task in %EXIT_DEAD state
 241  *
 242  * Called with write_lock(&tasklist_lock) held.
 243  */
 244 static inline void ptrace_release_task(struct task_struct *task)
 245 {
 246         BUG_ON(!list_empty(&task->ptraced));
 247         ptrace_unlink(task);
 248         BUG_ON(!list_empty(&task->ptrace_entry));
 249 }
 250
 251 #ifndef force_successful_syscall_return
 252 /*
 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).
 262  */
 263 #define force_successful_syscall_return() do { } while (0)
 264 #endif
 265
 266 #ifndef is_syscall_success
 267 /*
 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.
 271  */
 272 #define is_syscall_success(regs) (!IS_ERR_VALUE((unsigned long)(regs_return_value(regs))))
 273 #endif
 274
 275 /*
 276  * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
 277  *
 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.
 281  */
 282
 283 #ifndef arch_has_single_step
 284 /**
 285  * arch_has_single_step - does this CPU support user-mode single-step?
 286  *
 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.
 292  */
 293 #define arch_has_single_step()          (0)
 294
 295 /**
 296  * user_enable_single_step - single-step in user-mode task
 297  * @task: either current or a task stopped in %TASK_TRACED
 298  *
 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.
 303  */
 304 static inline void user_enable_single_step(struct task_struct *task)
 305 {
 306         BUG();                  /* This can never be called.  */
 307 }
 308
 309 /**
 310  * user_disable_single_step - cancel user-mode single-step
 311  * @task: either current or a task stopped in %TASK_TRACED
 312  *
 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()
 316  * returned zero.
 317  */
 318 static inline void user_disable_single_step(struct task_struct *task)
 319 {
 320 }
 321 #else
 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 */
 325
 326 #ifndef arch_has_block_step
 327 /**
 328  * arch_has_block_step - does this CPU support user-mode block-step?
 329  *
 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.
 335  */
 336 #define arch_has_block_step()           (0)
 337
 338 /**
 339  * user_enable_block_step - step until branch in user-mode task
 340  * @task: either current or a task stopped in %TASK_TRACED
 341  *
 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.
 346  */
 347 static inline void user_enable_block_step(struct task_struct *task)
 348 {
 349         BUG();                  /* This can never be called.  */
 350 }
 351 #else
 352 extern void user_enable_block_step(struct task_struct *);
 353 #endif  /* arch_has_block_step */
 354
 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);
 358 #else
 359 static inline void user_single_step_siginfo(struct task_struct *tsk,
 360                                 struct pt_regs *regs, siginfo_t *info)
 361 {
 362         memset(info, 0, sizeof(*info));
 363         info->si_signo = SIGTRAP;
 364 }
 365 #endif
 366
 367 #ifndef arch_ptrace_stop_needed
 368 /**
 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
 372  *
 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.
 381  */
 382 #define arch_ptrace_stop_needed(code, info)     (0)
 383 #endif
 384
 385 #ifndef arch_ptrace_stop
 386 /**
 387  * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
 388  * @code:       current->exit_code value ptrace will stop with
 389  * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
 390  *
 391  * This is called with no locks held when arch_ptrace_stop_needed() has
 392  * just returned nonzero.  It is allowed to block, e.g. for user memory
 393  * access.  The arch can have machine-specific work to be done before
 394  * ptrace stops.  On ia64, register backing store gets written back to user
 395  * memory here.  Since this can be costly (requires dropping the siglock),
 396  * we only do it when the arch requires it for this particular stop, as
 397  * indicated by arch_ptrace_stop_needed().
 398  */
 399 #define arch_ptrace_stop(code, info)            do { } while (0)
 400 #endif
 401
 402 extern int task_current_syscall(struct task_struct *target, long *callno,
 403                                 unsigned long args[6], unsigned int maxargs,
 404                                 unsigned long *sp, unsigned long *pc);
 405
 406 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 407 extern int ptrace_get_breakpoints(struct task_struct *tsk);
 408 extern void ptrace_put_breakpoints(struct task_struct *tsk);
 409 #else
 410 static inline void ptrace_put_breakpoints(struct task_struct *tsk) { }
 411 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 412
 413 #endif /* __KERNEL */
 414
 415 #endif