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 #include <linux/bug.h>                  /* For BUG_ON.  */
 112
 113
 114 extern long arch_ptrace(struct task_struct *child, long request,
 115                         unsigned long addr, unsigned long data);
 116 extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
 117 extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
 118 extern void ptrace_disable(struct task_struct *);
 119 extern int ptrace_check_attach(struct task_struct *task, bool ignore_state);
 120 extern int ptrace_request(struct task_struct *child, long request,
 121                           unsigned long addr, unsigned long data);
 122 extern void ptrace_notify(int exit_code);
 123 extern void __ptrace_link(struct task_struct *child,
 124                           struct task_struct *new_parent);
 125 extern void __ptrace_unlink(struct task_struct *child);
 126 extern void exit_ptrace(struct task_struct *tracer);
 127 #define PTRACE_MODE_READ        0x01
 128 #define PTRACE_MODE_ATTACH      0x02
 129 #define PTRACE_MODE_NOAUDIT     0x04
 130 /* Returns 0 on success, -errno on denial. */
 131 extern int __ptrace_may_access(struct task_struct *task, unsigned int mode);
 132 /* Returns true on success, false on denial. */
 133 extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
 134
 135 static inline int ptrace_reparented(struct task_struct *child)
 136 {
 137         return !same_thread_group(child->real_parent, child->parent);
 138 }
 139
 140 static inline void ptrace_unlink(struct task_struct *child)
 141 {
 142         if (unlikely(child->ptrace))
 143                 __ptrace_unlink(child);
 144 }
 145
 146 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
 147                             unsigned long data);
 148 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
 149                             unsigned long data);
 150
 151 /**
 152  * ptrace_parent - return the task that is tracing the given task
 153  * @task: task to consider
 154  *
 155  * Returns %NULL if no one is tracing @task, or the &struct task_struct
 156  * pointer to its tracer.
 157  *
 158  * Must called under rcu_read_lock().  The pointer returned might be kept
 159  * live only by RCU.  During exec, this may be called with task_lock() held
 160  * on @task, still held from when check_unsafe_exec() was called.
 161  */
 162 static inline struct task_struct *ptrace_parent(struct task_struct *task)
 163 {
 164         if (unlikely(task->ptrace))
 165                 return rcu_dereference(task->parent);
 166         return NULL;
 167 }
 168
 169 /**
 170  * ptrace_event_enabled - test whether a ptrace event is enabled
 171  * @task: ptracee of interest
 172  * @event: %PTRACE_EVENT_* to test
 173  *
 174  * Test whether @event is enabled for ptracee @task.
 175  *
 176  * Returns %true if @event is enabled, %false otherwise.
 177  */
 178 static inline bool ptrace_event_enabled(struct task_struct *task, int event)
 179 {
 180         return task->ptrace & PT_EVENT_FLAG(event);
 181 }
 182
 183 /**
 184  * ptrace_event - possibly stop for a ptrace event notification
 185  * @event:      %PTRACE_EVENT_* value to report
 186  * @message:    value for %PTRACE_GETEVENTMSG to return
 187  *
 188  * Check whether @event is enabled and, if so, report @event and @message
 189  * to the ptrace parent.
 190  *
 191  * Called without locks.
 192  */
 193 static inline void ptrace_event(int event, unsigned long message)
 194 {
 195         if (unlikely(ptrace_event_enabled(current, event))) {
 196                 current->ptrace_message = message;
 197                 ptrace_notify((event << 8) | SIGTRAP);
 198         } else if (event == PTRACE_EVENT_EXEC) {
 199                 /* legacy EXEC report via SIGTRAP */
 200                 if ((current->ptrace & (PT_PTRACED|PT_SEIZED)) == PT_PTRACED)
 201                         send_sig(SIGTRAP, current, 0);
 202         }
 203 }
 204
 205 /**
 206  * ptrace_init_task - initialize ptrace state for a new child
 207  * @child:              new child task
 208  * @ptrace:             true if child should be ptrace'd by parent's tracer
 209  *
 210  * This is called immediately after adding @child to its parent's children
 211  * list.  @ptrace is false in the normal case, and true to ptrace @child.
 212  *
 213  * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
 214  */
 215 static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
 216 {
 217         INIT_LIST_HEAD(&child->ptrace_entry);
 218         INIT_LIST_HEAD(&child->ptraced);
 219 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 220         atomic_set(&child->ptrace_bp_refcnt, 1);
 221 #endif
 222         child->jobctl = 0;
 223         child->ptrace = 0;
 224         child->parent = child->real_parent;
 225
 226         if (unlikely(ptrace) && current->ptrace) {
 227                 child->ptrace = current->ptrace;
 228                 __ptrace_link(child, current->parent);
 229
 230                 if (child->ptrace & PT_SEIZED)
 231                         task_set_jobctl_pending(child, JOBCTL_TRAP_STOP);
 232                 else
 233                         sigaddset(&child->pending.signal, SIGSTOP);
 234
 235                 set_tsk_thread_flag(child, TIF_SIGPENDING);
 236         }
 237 }
 238
 239 /**
 240  * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
 241  * @task:       task in %EXIT_DEAD state
 242  *
 243  * Called with write_lock(&tasklist_lock) held.
 244  */
 245 static inline void ptrace_release_task(struct task_struct *task)
 246 {
 247         BUG_ON(!list_empty(&task->ptraced));
 248         ptrace_unlink(task);
 249         BUG_ON(!list_empty(&task->ptrace_entry));
 250 }
 251
 252 #ifndef force_successful_syscall_return
 253 /*
 254  * System call handlers that, upon successful completion, need to return a
 255  * negative value should call force_successful_syscall_return() right before
 256  * returning.  On architectures where the syscall convention provides for a
 257  * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
 258  * others), this macro can be used to ensure that the error flag will not get
 259  * set.  On architectures which do not support a separate error flag, the macro
 260  * is a no-op and the spurious error condition needs to be filtered out by some
 261  * other means (e.g., in user-level, by passing an extra argument to the
 262  * syscall handler, or something along those lines).
 263  */
 264 #define force_successful_syscall_return() do { } while (0)
 265 #endif
 266
 267 #ifndef is_syscall_success
 268 /*
 269  * On most systems we can tell if a syscall is a success based on if the retval
 270  * is an error value.  On some systems like ia64 and powerpc they have different
 271  * indicators of success/failure and must define their own.
 272  */
 273 #define is_syscall_success(regs) (!IS_ERR_VALUE((unsigned long)(regs_return_value(regs))))
 274 #endif
 275
 276 /*
 277  * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
 278  *
 279  * These do-nothing inlines are used when the arch does not
 280  * implement single-step.  The kerneldoc comments are here
 281  * to document the interface for all arch definitions.
 282  */
 283
 284 #ifndef arch_has_single_step
 285 /**
 286  * arch_has_single_step - does this CPU support user-mode single-step?
 287  *
 288  * If this is defined, then there must be function declarations or
 289  * inlines for user_enable_single_step() and user_disable_single_step().
 290  * arch_has_single_step() should evaluate to nonzero iff the machine
 291  * supports instruction single-step for user mode.
 292  * It can be a constant or it can test a CPU feature bit.
 293  */
 294 #define arch_has_single_step()          (0)
 295
 296 /**
 297  * user_enable_single_step - single-step in user-mode task
 298  * @task: either current or a task stopped in %TASK_TRACED
 299  *
 300  * This can only be called when arch_has_single_step() has returned nonzero.
 301  * Set @task so that when it returns to user mode, it will trap after the
 302  * next single instruction executes.  If arch_has_block_step() is defined,
 303  * this must clear the effects of user_enable_block_step() too.
 304  */
 305 static inline void user_enable_single_step(struct task_struct *task)
 306 {
 307         BUG();                  /* This can never be called.  */
 308 }
 309
 310 /**
 311  * user_disable_single_step - cancel user-mode single-step
 312  * @task: either current or a task stopped in %TASK_TRACED
 313  *
 314  * Clear @task of the effects of user_enable_single_step() and
 315  * user_enable_block_step().  This can be called whether or not either
 316  * of those was ever called on @task, and even if arch_has_single_step()
 317  * returned zero.
 318  */
 319 static inline void user_disable_single_step(struct task_struct *task)
 320 {
 321 }
 322 #else
 323 extern void user_enable_single_step(struct task_struct *);
 324 extern void user_disable_single_step(struct task_struct *);
 325 #endif  /* arch_has_single_step */
 326
 327 #ifndef arch_has_block_step
 328 /**
 329  * arch_has_block_step - does this CPU support user-mode block-step?
 330  *
 331  * If this is defined, then there must be a function declaration or inline
 332  * for user_enable_block_step(), and arch_has_single_step() must be defined
 333  * too.  arch_has_block_step() should evaluate to nonzero iff the machine
 334  * supports step-until-branch for user mode.  It can be a constant or it
 335  * can test a CPU feature bit.
 336  */
 337 #define arch_has_block_step()           (0)
 338
 339 /**
 340  * user_enable_block_step - step until branch in user-mode task
 341  * @task: either current or a task stopped in %TASK_TRACED
 342  *
 343  * This can only be called when arch_has_block_step() has returned nonzero,
 344  * and will never be called when single-instruction stepping is being used.
 345  * Set @task so that when it returns to user mode, it will trap after the
 346  * next branch or trap taken.
 347  */
 348 static inline void user_enable_block_step(struct task_struct *task)
 349 {
 350         BUG();                  /* This can never be called.  */
 351 }
 352 #else
 353 extern void user_enable_block_step(struct task_struct *);
 354 #endif  /* arch_has_block_step */
 355
 356 #ifdef ARCH_HAS_USER_SINGLE_STEP_INFO
 357 extern void user_single_step_siginfo(struct task_struct *tsk,
 358                                 struct pt_regs *regs, siginfo_t *info);
 359 #else
 360 static inline void user_single_step_siginfo(struct task_struct *tsk,
 361                                 struct pt_regs *regs, siginfo_t *info)
 362 {
 363         memset(info, 0, sizeof(*info));
 364         info->si_signo = SIGTRAP;
 365 }
 366 #endif
 367
 368 #ifndef arch_ptrace_stop_needed
 369 /**
 370  * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
 371  * @code:       current->exit_code value ptrace will stop with
 372  * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
 373  *
 374  * This is called with the siglock held, to decide whether or not it's
 375  * necessary to release the siglock and call arch_ptrace_stop() with the
 376  * same @code and @info arguments.  It can be defined to a constant if
 377  * arch_ptrace_stop() is never required, or always is.  On machines where
 378  * this makes sense, it should be defined to a quick test to optimize out
 379  * calling arch_ptrace_stop() when it would be superfluous.  For example,
 380  * if the thread has not been back to user mode since the last stop, the
 381  * thread state might indicate that nothing needs to be done.
 382  */
 383 #define arch_ptrace_stop_needed(code, info)     (0)
 384 #endif
 385
 386 #ifndef arch_ptrace_stop
 387 /**
 388  * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
 389  * @code:       current->exit_code value ptrace will stop with
 390  * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
 391  *
 392  * This is called with no locks held when arch_ptrace_stop_needed() has
 393  * just returned nonzero.  It is allowed to block, e.g. for user memory
 394  * access.  The arch can have machine-specific work to be done before
 395  * ptrace stops.  On ia64, register backing store gets written back to user
 396  * memory here.  Since this can be costly (requires dropping the siglock),
 397  * we only do it when the arch requires it for this particular stop, as
 398  * indicated by arch_ptrace_stop_needed().
 399  */
 400 #define arch_ptrace_stop(code, info)            do { } while (0)
 401 #endif
 402
 403 extern int task_current_syscall(struct task_struct *target, long *callno,
 404                                 unsigned long args[6], unsigned int maxargs,
 405                                 unsigned long *sp, unsigned long *pc);
 406
 407 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 408 extern int ptrace_get_breakpoints(struct task_struct *tsk);
 409 extern void ptrace_put_breakpoints(struct task_struct *tsk);
 410 #else
 411 static inline void ptrace_put_breakpoints(struct task_struct *tsk) { }
 412 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 413
 414 #endif /* __KERNEL */
 415
 416 #endif