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 struct task_struct *ptrace_get_task_struct(pid_t pid);
  85 extern int ptrace_traceme(void);
  86 extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
  87 extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
  88 extern int ptrace_attach(struct task_struct *tsk);
  89 extern int ptrace_detach(struct task_struct *, unsigned int);
  90 extern void ptrace_disable(struct task_struct *);
  91 extern int ptrace_check_attach(struct task_struct *task, int kill);
  92 extern int ptrace_request(struct task_struct *child, long request, long addr, long data);
  93 extern void ptrace_notify(int exit_code);
  94 extern void __ptrace_link(struct task_struct *child,
  95                           struct task_struct *new_parent);
  96 extern void __ptrace_unlink(struct task_struct *child);
  97 extern void ptrace_untrace(struct task_struct *child);
  98 #define PTRACE_MODE_READ   1
  99 #define PTRACE_MODE_ATTACH 2
 100 /* Returns 0 on success, -errno on denial. */
 101 extern int __ptrace_may_access(struct task_struct *task, unsigned int mode);
 102 /* Returns true on success, false on denial. */
 103 extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
 104
 105 static inline int ptrace_reparented(struct task_struct *child)
 106 {
 107         return child->real_parent != child->parent;
 108 }
 109 static inline void ptrace_link(struct task_struct *child,
 110                                struct task_struct *new_parent)
 111 {
 112         if (unlikely(child->ptrace))
 113                 __ptrace_link(child, new_parent);
 114 }
 115 static inline void ptrace_unlink(struct task_struct *child)
 116 {
 117         if (unlikely(child->ptrace))
 118                 __ptrace_unlink(child);
 119 }
 120
 121 int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data);
 122 int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data);
 123
 124 /**
 125  * task_ptrace - return %PT_* flags that apply to a task
 126  * @task:       pointer to &task_struct in question
 127  *
 128  * Returns the %PT_* flags that apply to @task.
 129  */
 130 static inline int task_ptrace(struct task_struct *task)
 131 {
 132         return task->ptrace;
 133 }
 134
 135 /**
 136  * ptrace_event - possibly stop for a ptrace event notification
 137  * @mask:       %PT_* bit to check in @current->ptrace
 138  * @event:      %PTRACE_EVENT_* value to report if @mask is set
 139  * @message:    value for %PTRACE_GETEVENTMSG to return
 140  *
 141  * This checks the @mask bit to see if ptrace wants stops for this event.
 142  * If so we stop, reporting @event and @message to the ptrace parent.
 143  *
 144  * Returns nonzero if we did a ptrace notification, zero if not.
 145  *
 146  * Called without locks.
 147  */
 148 static inline int ptrace_event(int mask, int event, unsigned long message)
 149 {
 150         if (mask && likely(!(current->ptrace & mask)))
 151                 return 0;
 152         current->ptrace_message = message;
 153         ptrace_notify((event << 8) | SIGTRAP);
 154         return 1;
 155 }
 156
 157 #ifndef force_successful_syscall_return
 158 /*
 159  * System call handlers that, upon successful completion, need to return a
 160  * negative value should call force_successful_syscall_return() right before
 161  * returning.  On architectures where the syscall convention provides for a
 162  * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
 163  * others), this macro can be used to ensure that the error flag will not get
 164  * set.  On architectures which do not support a separate error flag, the macro
 165  * is a no-op and the spurious error condition needs to be filtered out by some
 166  * other means (e.g., in user-level, by passing an extra argument to the
 167  * syscall handler, or something along those lines).
 168  */
 169 #define force_successful_syscall_return() do { } while (0)
 170 #endif
 171
 172 /*
 173  * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
 174  *
 175  * These do-nothing inlines are used when the arch does not
 176  * implement single-step.  The kerneldoc comments are here
 177  * to document the interface for all arch definitions.
 178  */
 179
 180 #ifndef arch_has_single_step
 181 /**
 182  * arch_has_single_step - does this CPU support user-mode single-step?
 183  *
 184  * If this is defined, then there must be function declarations or
 185  * inlines for user_enable_single_step() and user_disable_single_step().
 186  * arch_has_single_step() should evaluate to nonzero iff the machine
 187  * supports instruction single-step for user mode.
 188  * It can be a constant or it can test a CPU feature bit.
 189  */
 190 #define arch_has_single_step()          (0)
 191
 192 /**
 193  * user_enable_single_step - single-step in user-mode task
 194  * @task: either current or a task stopped in %TASK_TRACED
 195  *
 196  * This can only be called when arch_has_single_step() has returned nonzero.
 197  * Set @task so that when it returns to user mode, it will trap after the
 198  * next single instruction executes.  If arch_has_block_step() is defined,
 199  * this must clear the effects of user_enable_block_step() too.
 200  */
 201 static inline void user_enable_single_step(struct task_struct *task)
 202 {
 203         BUG();                  /* This can never be called.  */
 204 }
 205
 206 /**
 207  * user_disable_single_step - cancel user-mode single-step
 208  * @task: either current or a task stopped in %TASK_TRACED
 209  *
 210  * Clear @task of the effects of user_enable_single_step() and
 211  * user_enable_block_step().  This can be called whether or not either
 212  * of those was ever called on @task, and even if arch_has_single_step()
 213  * returned zero.
 214  */
 215 static inline void user_disable_single_step(struct task_struct *task)
 216 {
 217 }
 218 #endif  /* arch_has_single_step */
 219
 220 #ifndef arch_has_block_step
 221 /**
 222  * arch_has_block_step - does this CPU support user-mode block-step?
 223  *
 224  * If this is defined, then there must be a function declaration or inline
 225  * for user_enable_block_step(), and arch_has_single_step() must be defined
 226  * too.  arch_has_block_step() should evaluate to nonzero iff the machine
 227  * supports step-until-branch for user mode.  It can be a constant or it
 228  * can test a CPU feature bit.
 229  */
 230 #define arch_has_block_step()           (0)
 231
 232 /**
 233  * user_enable_block_step - step until branch in user-mode task
 234  * @task: either current or a task stopped in %TASK_TRACED
 235  *
 236  * This can only be called when arch_has_block_step() has returned nonzero,
 237  * and will never be called when single-instruction stepping is being used.
 238  * Set @task so that when it returns to user mode, it will trap after the
 239  * next branch or trap taken.
 240  */
 241 static inline void user_enable_block_step(struct task_struct *task)
 242 {
 243         BUG();                  /* This can never be called.  */
 244 }
 245 #endif  /* arch_has_block_step */
 246
 247 #ifndef arch_ptrace_stop_needed
 248 /**
 249  * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
 250  * @code:       current->exit_code value ptrace will stop with
 251  * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
 252  *
 253  * This is called with the siglock held, to decide whether or not it's
 254  * necessary to release the siglock and call arch_ptrace_stop() with the
 255  * same @code and @info arguments.  It can be defined to a constant if
 256  * arch_ptrace_stop() is never required, or always is.  On machines where
 257  * this makes sense, it should be defined to a quick test to optimize out
 258  * calling arch_ptrace_stop() when it would be superfluous.  For example,
 259  * if the thread has not been back to user mode since the last stop, the
 260  * thread state might indicate that nothing needs to be done.
 261  */
 262 #define arch_ptrace_stop_needed(code, info)     (0)
 263 #endif
 264
 265 #ifndef arch_ptrace_stop
 266 /**
 267  * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
 268  * @code:       current->exit_code value ptrace will stop with
 269  * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
 270  *
 271  * This is called with no locks held when arch_ptrace_stop_needed() has
 272  * just returned nonzero.  It is allowed to block, e.g. for user memory
 273  * access.  The arch can have machine-specific work to be done before
 274  * ptrace stops.  On ia64, register backing store gets written back to user
 275  * memory here.  Since this can be costly (requires dropping the siglock),
 276  * we only do it when the arch requires it for this particular stop, as
 277  * indicated by arch_ptrace_stop_needed().
 278  */
 279 #define arch_ptrace_stop(code, info)            do { } while (0)
 280 #endif
 281
 282 #endif
 283
 284 #endif