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 static inline void ptrace_link(struct task_struct *child,
 109                                struct task_struct *new_parent)
 110 {
 111         if (unlikely(child->ptrace))
 112                 __ptrace_link(child, new_parent);
 113 }
 114 static inline void ptrace_unlink(struct task_struct *child)
 115 {
 116         if (unlikely(child->ptrace))
 117                 __ptrace_unlink(child);
 118 }
 119
 120 int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data);
 121 int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data);
 122
 123 /**
 124  * task_ptrace - return %PT_* flags that apply to a task
 125  * @task:       pointer to &task_struct in question
 126  *
 127  * Returns the %PT_* flags that apply to @task.
 128  */
 129 static inline int task_ptrace(struct task_struct *task)
 130 {
 131         return task->ptrace;
 132 }
 133
 134 /**
 135  * ptrace_event - possibly stop for a ptrace event notification
 136  * @mask:       %PT_* bit to check in @current->ptrace
 137  * @event:      %PTRACE_EVENT_* value to report if @mask is set
 138  * @message:    value for %PTRACE_GETEVENTMSG to return
 139  *
 140  * This checks the @mask bit to see if ptrace wants stops for this event.
 141  * If so we stop, reporting @event and @message to the ptrace parent.
 142  *
 143  * Returns nonzero if we did a ptrace notification, zero if not.
 144  *
 145  * Called without locks.
 146  */
 147 static inline int ptrace_event(int mask, int event, unsigned long message)
 148 {
 149         if (mask && likely(!(current->ptrace & mask)))
 150                 return 0;
 151         current->ptrace_message = message;
 152         ptrace_notify((event << 8) | SIGTRAP);
 153         return 1;
 154 }
 155
 156 /**
 157  * ptrace_init_task - initialize ptrace state for a new child
 158  * @child:              new child task
 159  * @ptrace:             true if child should be ptrace'd by parent's tracer
 160  *
 161  * This is called immediately after adding @child to its parent's children
 162  * list.  @ptrace is false in the normal case, and true to ptrace @child.
 163  *
 164  * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
 165  */
 166 static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
 167 {
 168         INIT_LIST_HEAD(&child->ptrace_entry);
 169         INIT_LIST_HEAD(&child->ptraced);
 170         child->parent = child->real_parent;
 171         child->ptrace = 0;
 172         if (unlikely(ptrace)) {
 173                 child->ptrace = current->ptrace;
 174                 ptrace_link(child, current->parent);
 175         }
 176 }
 177
 178 /**
 179  * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
 180  * @task:       task in %EXIT_DEAD state
 181  *
 182  * Called with write_lock(&tasklist_lock) held.
 183  */
 184 static inline void ptrace_release_task(struct task_struct *task)
 185 {
 186         BUG_ON(!list_empty(&task->ptraced));
 187         ptrace_unlink(task);
 188         BUG_ON(!list_empty(&task->ptrace_entry));
 189 }
 190
 191 #ifndef force_successful_syscall_return
 192 /*
 193  * System call handlers that, upon successful completion, need to return a
 194  * negative value should call force_successful_syscall_return() right before
 195  * returning.  On architectures where the syscall convention provides for a
 196  * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
 197  * others), this macro can be used to ensure that the error flag will not get
 198  * set.  On architectures which do not support a separate error flag, the macro
 199  * is a no-op and the spurious error condition needs to be filtered out by some
 200  * other means (e.g., in user-level, by passing an extra argument to the
 201  * syscall handler, or something along those lines).
 202  */
 203 #define force_successful_syscall_return() do { } while (0)
 204 #endif
 205
 206 /*
 207  * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
 208  *
 209  * These do-nothing inlines are used when the arch does not
 210  * implement single-step.  The kerneldoc comments are here
 211  * to document the interface for all arch definitions.
 212  */
 213
 214 #ifndef arch_has_single_step
 215 /**
 216  * arch_has_single_step - does this CPU support user-mode single-step?
 217  *
 218  * If this is defined, then there must be function declarations or
 219  * inlines for user_enable_single_step() and user_disable_single_step().
 220  * arch_has_single_step() should evaluate to nonzero iff the machine
 221  * supports instruction single-step for user mode.
 222  * It can be a constant or it can test a CPU feature bit.
 223  */
 224 #define arch_has_single_step()          (0)
 225
 226 /**
 227  * user_enable_single_step - single-step in user-mode task
 228  * @task: either current or a task stopped in %TASK_TRACED
 229  *
 230  * This can only be called when arch_has_single_step() has returned nonzero.
 231  * Set @task so that when it returns to user mode, it will trap after the
 232  * next single instruction executes.  If arch_has_block_step() is defined,
 233  * this must clear the effects of user_enable_block_step() too.
 234  */
 235 static inline void user_enable_single_step(struct task_struct *task)
 236 {
 237         BUG();                  /* This can never be called.  */
 238 }
 239
 240 /**
 241  * user_disable_single_step - cancel user-mode single-step
 242  * @task: either current or a task stopped in %TASK_TRACED
 243  *
 244  * Clear @task of the effects of user_enable_single_step() and
 245  * user_enable_block_step().  This can be called whether or not either
 246  * of those was ever called on @task, and even if arch_has_single_step()
 247  * returned zero.
 248  */
 249 static inline void user_disable_single_step(struct task_struct *task)
 250 {
 251 }
 252 #endif  /* arch_has_single_step */
 253
 254 #ifndef arch_has_block_step
 255 /**
 256  * arch_has_block_step - does this CPU support user-mode block-step?
 257  *
 258  * If this is defined, then there must be a function declaration or inline
 259  * for user_enable_block_step(), and arch_has_single_step() must be defined
 260  * too.  arch_has_block_step() should evaluate to nonzero iff the machine
 261  * supports step-until-branch for user mode.  It can be a constant or it
 262  * can test a CPU feature bit.
 263  */
 264 #define arch_has_block_step()           (0)
 265
 266 /**
 267  * user_enable_block_step - step until branch in user-mode task
 268  * @task: either current or a task stopped in %TASK_TRACED
 269  *
 270  * This can only be called when arch_has_block_step() has returned nonzero,
 271  * and will never be called when single-instruction stepping is being used.
 272  * Set @task so that when it returns to user mode, it will trap after the
 273  * next branch or trap taken.
 274  */
 275 static inline void user_enable_block_step(struct task_struct *task)
 276 {
 277         BUG();                  /* This can never be called.  */
 278 }
 279 #endif  /* arch_has_block_step */
 280
 281 #ifndef arch_ptrace_stop_needed
 282 /**
 283  * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
 284  * @code:       current->exit_code value ptrace will stop with
 285  * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
 286  *
 287  * This is called with the siglock held, to decide whether or not it's
 288  * necessary to release the siglock and call arch_ptrace_stop() with the
 289  * same @code and @info arguments.  It can be defined to a constant if
 290  * arch_ptrace_stop() is never required, or always is.  On machines where
 291  * this makes sense, it should be defined to a quick test to optimize out
 292  * calling arch_ptrace_stop() when it would be superfluous.  For example,
 293  * if the thread has not been back to user mode since the last stop, the
 294  * thread state might indicate that nothing needs to be done.
 295  */
 296 #define arch_ptrace_stop_needed(code, info)     (0)
 297 #endif
 298
 299 #ifndef arch_ptrace_stop
 300 /**
 301  * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
 302  * @code:       current->exit_code value ptrace will stop with
 303  * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
 304  *
 305  * This is called with no locks held when arch_ptrace_stop_needed() has
 306  * just returned nonzero.  It is allowed to block, e.g. for user memory
 307  * access.  The arch can have machine-specific work to be done before
 308  * ptrace stops.  On ia64, register backing store gets written back to user
 309  * memory here.  Since this can be costly (requires dropping the siglock),
 310  * we only do it when the arch requires it for this particular stop, as
 311  * indicated by arch_ptrace_stop_needed().
 312  */
 313 #define arch_ptrace_stop(code, info)            do { } while (0)
 314 #endif
 315
 316 #ifndef arch_ptrace_untrace
 317 /*
 318  * Do machine-specific work before untracing child.
 319  *
 320  * This is called for a normal detach as well as from ptrace_exit()
 321  * when the tracing task dies.
 322  *
 323  * Called with write_lock(&tasklist_lock) held.
 324  */
 325 #define arch_ptrace_untrace(task)               do { } while (0)
 326 #endif
 327
 328 extern int task_current_syscall(struct task_struct *target, long *callno,
 329                                 unsigned long args[6], unsigned int maxargs,
 330                                 unsigned long *sp, unsigned long *pc);
 331
 332 #endif
 333
 334 #endif