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 /* options set using PTRACE_SETOPTIONS */
  31 #define PTRACE_O_TRACESYSGOOD   0x00000001
  32 #define PTRACE_O_TRACEFORK      0x00000002
  33 #define PTRACE_O_TRACEVFORK     0x00000004
  34 #define PTRACE_O_TRACECLONE     0x00000008
  35 #define PTRACE_O_TRACEEXEC      0x00000010
  36 #define PTRACE_O_TRACEVFORKDONE 0x00000020
  37 #define PTRACE_O_TRACEEXIT      0x00000040
  38
  39 #define PTRACE_O_MASK           0x0000007f
  40
  41 /* Wait extended result codes for the above trace options.  */
  42 #define PTRACE_EVENT_FORK       1
  43 #define PTRACE_EVENT_VFORK      2
  44 #define PTRACE_EVENT_CLONE      3
  45 #define PTRACE_EVENT_EXEC       4
  46 #define PTRACE_EVENT_VFORK_DONE 5
  47 #define PTRACE_EVENT_EXIT       6
  48
  49 #include <asm/ptrace.h>
  50
  51 #ifdef __KERNEL__
  52 /*
  53  * Ptrace flags
  54  *
  55  * The owner ship rules for task->ptrace which holds the ptrace
  56  * flags is simple.  When a task is running it owns it's task->ptrace
  57  * flags.  When the a task is stopped the ptracer owns task->ptrace.
  58  */
  59
  60 #define PT_PTRACED      0x00000001
  61 #define PT_DTRACE       0x00000002      /* delayed trace (used on m68k, i386) */
  62 #define PT_TRACESYSGOOD 0x00000004
  63 #define PT_PTRACE_CAP   0x00000008      /* ptracer can follow suid-exec */
  64 #define PT_TRACE_FORK   0x00000010
  65 #define PT_TRACE_VFORK  0x00000020
  66 #define PT_TRACE_CLONE  0x00000040
  67 #define PT_TRACE_EXEC   0x00000080
  68 #define PT_TRACE_VFORK_DONE     0x00000100
  69 #define PT_TRACE_EXIT   0x00000200
  70
  71 #define PT_TRACE_MASK   0x000003f4
  72
  73 /* single stepping state bits (used on ARM and PA-RISC) */
  74 #define PT_SINGLESTEP_BIT       31
  75 #define PT_SINGLESTEP           (1<<PT_SINGLESTEP_BIT)
  76 #define PT_BLOCKSTEP_BIT        30
  77 #define PT_BLOCKSTEP            (1<<PT_BLOCKSTEP_BIT)
  78
  79 #include <linux/compiler.h>             /* For unlikely.  */
  80 #include <linux/sched.h>                /* For struct task_struct.  */
  81
  82
  83 extern long arch_ptrace(struct task_struct *child, long request, long addr, long data);
  84 extern int ptrace_traceme(void);
  85 extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
  86 extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
  87 extern int ptrace_attach(struct task_struct *tsk);
  88 extern int ptrace_detach(struct task_struct *, unsigned int);
  89 extern void ptrace_disable(struct task_struct *);
  90 extern int ptrace_check_attach(struct task_struct *task, int kill);
  91 extern int ptrace_request(struct task_struct *child, long request, long addr, long data);
  92 extern void ptrace_notify(int exit_code);
  93 extern void __ptrace_link(struct task_struct *child,
  94                           struct task_struct *new_parent);
  95 extern void __ptrace_unlink(struct task_struct *child);
  96 extern void exit_ptrace(struct task_struct *tracer);
  97 #define PTRACE_MODE_READ   1
  98 #define PTRACE_MODE_ATTACH 2
  99 /* Returns 0 on success, -errno on denial. */
 100 extern int __ptrace_may_access(struct task_struct *task, unsigned int mode);
 101 /* Returns true on success, false on denial. */
 102 extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
 103
 104 static inline int ptrace_reparented(struct task_struct *child)
 105 {
 106         return child->real_parent != child->parent;
 107 }
 108
 109 static inline void ptrace_unlink(struct task_struct *child)
 110 {
 111         if (unlikely(child->ptrace))
 112                 __ptrace_unlink(child);
 113 }
 114
 115 int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data);
 116 int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data);
 117
 118 /**
 119  * task_ptrace - return %PT_* flags that apply to a task
 120  * @task:       pointer to &task_struct in question
 121  *
 122  * Returns the %PT_* flags that apply to @task.
 123  */
 124 static inline int task_ptrace(struct task_struct *task)
 125 {
 126         return task->ptrace;
 127 }
 128
 129 /**
 130  * ptrace_event - possibly stop for a ptrace event notification
 131  * @mask:       %PT_* bit to check in @current->ptrace
 132  * @event:      %PTRACE_EVENT_* value to report if @mask is set
 133  * @message:    value for %PTRACE_GETEVENTMSG to return
 134  *
 135  * This checks the @mask bit to see if ptrace wants stops for this event.
 136  * If so we stop, reporting @event and @message to the ptrace parent.
 137  *
 138  * Returns nonzero if we did a ptrace notification, zero if not.
 139  *
 140  * Called without locks.
 141  */
 142 static inline int ptrace_event(int mask, int event, unsigned long message)
 143 {
 144         if (mask && likely(!(current->ptrace & mask)))
 145                 return 0;
 146         current->ptrace_message = message;
 147         ptrace_notify((event << 8) | SIGTRAP);
 148         return 1;
 149 }
 150
 151 /**
 152  * ptrace_init_task - initialize ptrace state for a new child
 153  * @child:              new child task
 154  * @ptrace:             true if child should be ptrace'd by parent's tracer
 155  *
 156  * This is called immediately after adding @child to its parent's children
 157  * list.  @ptrace is false in the normal case, and true to ptrace @child.
 158  *
 159  * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
 160  */
 161 static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
 162 {
 163         INIT_LIST_HEAD(&child->ptrace_entry);
 164         INIT_LIST_HEAD(&child->ptraced);
 165         child->parent = child->real_parent;
 166         child->ptrace = 0;
 167         if (unlikely(ptrace) && (current->ptrace & PT_PTRACED)) {
 168                 child->ptrace = current->ptrace;
 169                 __ptrace_link(child, current->parent);
 170         }
 171
 172 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 173         atomic_set(&child->ptrace_bp_refcnt, 1);
 174 #endif
 175 }
 176
 177 /**
 178  * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
 179  * @task:       task in %EXIT_DEAD state
 180  *
 181  * Called with write_lock(&tasklist_lock) held.
 182  */
 183 static inline void ptrace_release_task(struct task_struct *task)
 184 {
 185         BUG_ON(!list_empty(&task->ptraced));
 186         ptrace_unlink(task);
 187         BUG_ON(!list_empty(&task->ptrace_entry));
 188 }
 189
 190 #ifndef force_successful_syscall_return
 191 /*
 192  * System call handlers that, upon successful completion, need to return a
 193  * negative value should call force_successful_syscall_return() right before
 194  * returning.  On architectures where the syscall convention provides for a
 195  * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
 196  * others), this macro can be used to ensure that the error flag will not get
 197  * set.  On architectures which do not support a separate error flag, the macro
 198  * is a no-op and the spurious error condition needs to be filtered out by some
 199  * other means (e.g., in user-level, by passing an extra argument to the
 200  * syscall handler, or something along those lines).
 201  */
 202 #define force_successful_syscall_return() do { } while (0)
 203 #endif
 204
 205 /*
 206  * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
 207  *
 208  * These do-nothing inlines are used when the arch does not
 209  * implement single-step.  The kerneldoc comments are here
 210  * to document the interface for all arch definitions.
 211  */
 212
 213 #ifndef arch_has_single_step
 214 /**
 215  * arch_has_single_step - does this CPU support user-mode single-step?
 216  *
 217  * If this is defined, then there must be function declarations or
 218  * inlines for user_enable_single_step() and user_disable_single_step().
 219  * arch_has_single_step() should evaluate to nonzero iff the machine
 220  * supports instruction single-step for user mode.
 221  * It can be a constant or it can test a CPU feature bit.
 222  */
 223 #define arch_has_single_step()          (0)
 224
 225 /**
 226  * user_enable_single_step - single-step in user-mode task
 227  * @task: either current or a task stopped in %TASK_TRACED
 228  *
 229  * This can only be called when arch_has_single_step() has returned nonzero.
 230  * Set @task so that when it returns to user mode, it will trap after the
 231  * next single instruction executes.  If arch_has_block_step() is defined,
 232  * this must clear the effects of user_enable_block_step() too.
 233  */
 234 static inline void user_enable_single_step(struct task_struct *task)
 235 {
 236         BUG();                  /* This can never be called.  */
 237 }
 238
 239 /**
 240  * user_disable_single_step - cancel user-mode single-step
 241  * @task: either current or a task stopped in %TASK_TRACED
 242  *
 243  * Clear @task of the effects of user_enable_single_step() and
 244  * user_enable_block_step().  This can be called whether or not either
 245  * of those was ever called on @task, and even if arch_has_single_step()
 246  * returned zero.
 247  */
 248 static inline void user_disable_single_step(struct task_struct *task)
 249 {
 250 }
 251 #endif  /* arch_has_single_step */
 252
 253 #ifndef arch_has_block_step
 254 /**
 255  * arch_has_block_step - does this CPU support user-mode block-step?
 256  *
 257  * If this is defined, then there must be a function declaration or inline
 258  * for user_enable_block_step(), and arch_has_single_step() must be defined
 259  * too.  arch_has_block_step() should evaluate to nonzero iff the machine
 260  * supports step-until-branch for user mode.  It can be a constant or it
 261  * can test a CPU feature bit.
 262  */
 263 #define arch_has_block_step()           (0)
 264
 265 /**
 266  * user_enable_block_step - step until branch in user-mode task
 267  * @task: either current or a task stopped in %TASK_TRACED
 268  *
 269  * This can only be called when arch_has_block_step() has returned nonzero,
 270  * and will never be called when single-instruction stepping is being used.
 271  * Set @task so that when it returns to user mode, it will trap after the
 272  * next branch or trap taken.
 273  */
 274 static inline void user_enable_block_step(struct task_struct *task)
 275 {
 276         BUG();                  /* This can never be called.  */
 277 }
 278 #endif  /* arch_has_block_step */
 279
 280 #ifdef ARCH_HAS_USER_SINGLE_STEP_INFO
 281 extern void user_single_step_siginfo(struct task_struct *tsk,
 282                                 struct pt_regs *regs, siginfo_t *info);
 283 #else
 284 static inline void user_single_step_siginfo(struct task_struct *tsk,
 285                                 struct pt_regs *regs, siginfo_t *info)
 286 {
 287         memset(info, 0, sizeof(*info));
 288         info->si_signo = SIGTRAP;
 289 }
 290 #endif
 291
 292 #ifndef arch_ptrace_stop_needed
 293 /**
 294  * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
 295  * @code:       current->exit_code value ptrace will stop with
 296  * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
 297  *
 298  * This is called with the siglock held, to decide whether or not it's
 299  * necessary to release the siglock and call arch_ptrace_stop() with the
 300  * same @code and @info arguments.  It can be defined to a constant if
 301  * arch_ptrace_stop() is never required, or always is.  On machines where
 302  * this makes sense, it should be defined to a quick test to optimize out
 303  * calling arch_ptrace_stop() when it would be superfluous.  For example,
 304  * if the thread has not been back to user mode since the last stop, the
 305  * thread state might indicate that nothing needs to be done.
 306  */
 307 #define arch_ptrace_stop_needed(code, info)     (0)
 308 #endif
 309
 310 #ifndef arch_ptrace_stop
 311 /**
 312  * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
 313  * @code:       current->exit_code value ptrace will stop with
 314  * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
 315  *
 316  * This is called with no locks held when arch_ptrace_stop_needed() has
 317  * just returned nonzero.  It is allowed to block, e.g. for user memory
 318  * access.  The arch can have machine-specific work to be done before
 319  * ptrace stops.  On ia64, register backing store gets written back to user
 320  * memory here.  Since this can be costly (requires dropping the siglock),
 321  * we only do it when the arch requires it for this particular stop, as
 322  * indicated by arch_ptrace_stop_needed().
 323  */
 324 #define arch_ptrace_stop(code, info)            do { } while (0)
 325 #endif
 326
 327 #ifndef arch_ptrace_untrace
 328 /*
 329  * Do machine-specific work before untracing child.
 330  *
 331  * This is called for a normal detach as well as from ptrace_exit()
 332  * when the tracing task dies.
 333  *
 334  * Called with write_lock(&tasklist_lock) held.
 335  */
 336 #define arch_ptrace_untrace(task)               do { } while (0)
 337 #endif
 338
 339 extern int task_current_syscall(struct task_struct *target, long *callno,
 340                                 unsigned long args[6], unsigned int maxargs,
 341                                 unsigned long *sp, unsigned long *pc);
 342
 343 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 344 extern int ptrace_get_breakpoints(struct task_struct *tsk);
 345 extern void ptrace_put_breakpoints(struct task_struct *tsk);
 346 #else
 347 static inline void ptrace_put_breakpoints(struct task_struct *tsk) { }
 348 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 349
 350 #endif /* __KERNEL */
 351
 352 #endif