linux/include/linux/ptrace.h
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   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
  83extern long arch_ptrace(struct task_struct *child, long request, long addr, long data);
  84extern int ptrace_traceme(void);
  85extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
  86extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
  87extern int ptrace_attach(struct task_struct *tsk);
  88extern int ptrace_detach(struct task_struct *, unsigned int);
  89extern void ptrace_disable(struct task_struct *);
  90extern int ptrace_check_attach(struct task_struct *task, int kill);
  91extern int ptrace_request(struct task_struct *child, long request, long addr, long data);
  92extern void ptrace_notify(int exit_code);
  93extern void __ptrace_link(struct task_struct *child,
  94                          struct task_struct *new_parent);
  95extern void __ptrace_unlink(struct task_struct *child);
  96extern 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. */
 100extern int __ptrace_may_access(struct task_struct *task, unsigned int mode);
 101/* Returns true on success, false on denial. */
 102extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
 103
 104static inline int ptrace_reparented(struct task_struct *child)
 105{
 106        return child->real_parent != child->parent;
 107}
 108
 109static inline void ptrace_unlink(struct task_struct *child)
 110{
 111        if (unlikely(child->ptrace))
 112                __ptrace_unlink(child);
 113}
 114
 115int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data);
 116int 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 */
 124static 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 */
 142static 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 */
 161static 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
 173/**
 174 * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
 175 * @task:       task in %EXIT_DEAD state
 176 *
 177 * Called with write_lock(&tasklist_lock) held.
 178 */
 179static inline void ptrace_release_task(struct task_struct *task)
 180{
 181        BUG_ON(!list_empty(&task->ptraced));
 182        ptrace_unlink(task);
 183        BUG_ON(!list_empty(&task->ptrace_entry));
 184}
 185
 186#ifndef force_successful_syscall_return
 187/*
 188 * System call handlers that, upon successful completion, need to return a
 189 * negative value should call force_successful_syscall_return() right before
 190 * returning.  On architectures where the syscall convention provides for a
 191 * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
 192 * others), this macro can be used to ensure that the error flag will not get
 193 * set.  On architectures which do not support a separate error flag, the macro
 194 * is a no-op and the spurious error condition needs to be filtered out by some
 195 * other means (e.g., in user-level, by passing an extra argument to the
 196 * syscall handler, or something along those lines).
 197 */
 198#define force_successful_syscall_return() do { } while (0)
 199#endif
 200
 201/*
 202 * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
 203 *
 204 * These do-nothing inlines are used when the arch does not
 205 * implement single-step.  The kerneldoc comments are here
 206 * to document the interface for all arch definitions.
 207 */
 208
 209#ifndef arch_has_single_step
 210/**
 211 * arch_has_single_step - does this CPU support user-mode single-step?
 212 *
 213 * If this is defined, then there must be function declarations or
 214 * inlines for user_enable_single_step() and user_disable_single_step().
 215 * arch_has_single_step() should evaluate to nonzero iff the machine
 216 * supports instruction single-step for user mode.
 217 * It can be a constant or it can test a CPU feature bit.
 218 */
 219#define arch_has_single_step()          (0)
 220
 221/**
 222 * user_enable_single_step - single-step in user-mode task
 223 * @task: either current or a task stopped in %TASK_TRACED
 224 *
 225 * This can only be called when arch_has_single_step() has returned nonzero.
 226 * Set @task so that when it returns to user mode, it will trap after the
 227 * next single instruction executes.  If arch_has_block_step() is defined,
 228 * this must clear the effects of user_enable_block_step() too.
 229 */
 230static inline void user_enable_single_step(struct task_struct *task)
 231{
 232        BUG();                  /* This can never be called.  */
 233}
 234
 235/**
 236 * user_disable_single_step - cancel user-mode single-step
 237 * @task: either current or a task stopped in %TASK_TRACED
 238 *
 239 * Clear @task of the effects of user_enable_single_step() and
 240 * user_enable_block_step().  This can be called whether or not either
 241 * of those was ever called on @task, and even if arch_has_single_step()
 242 * returned zero.
 243 */
 244static inline void user_disable_single_step(struct task_struct *task)
 245{
 246}
 247#endif  /* arch_has_single_step */
 248
 249#ifndef arch_has_block_step
 250/**
 251 * arch_has_block_step - does this CPU support user-mode block-step?
 252 *
 253 * If this is defined, then there must be a function declaration or inline
 254 * for user_enable_block_step(), and arch_has_single_step() must be defined
 255 * too.  arch_has_block_step() should evaluate to nonzero iff the machine
 256 * supports step-until-branch for user mode.  It can be a constant or it
 257 * can test a CPU feature bit.
 258 */
 259#define arch_has_block_step()           (0)
 260
 261/**
 262 * user_enable_block_step - step until branch in user-mode task
 263 * @task: either current or a task stopped in %TASK_TRACED
 264 *
 265 * This can only be called when arch_has_block_step() has returned nonzero,
 266 * and will never be called when single-instruction stepping is being used.
 267 * Set @task so that when it returns to user mode, it will trap after the
 268 * next branch or trap taken.
 269 */
 270static inline void user_enable_block_step(struct task_struct *task)
 271{
 272        BUG();                  /* This can never be called.  */
 273}
 274#endif  /* arch_has_block_step */
 275
 276#ifdef ARCH_HAS_USER_SINGLE_STEP_INFO
 277extern void user_single_step_siginfo(struct task_struct *tsk,
 278                                struct pt_regs *regs, siginfo_t *info);
 279#else
 280static inline void user_single_step_siginfo(struct task_struct *tsk,
 281                                struct pt_regs *regs, siginfo_t *info)
 282{
 283        memset(info, 0, sizeof(*info));
 284        info->si_signo = SIGTRAP;
 285}
 286#endif
 287
 288#ifndef arch_ptrace_stop_needed
 289/**
 290 * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
 291 * @code:       current->exit_code value ptrace will stop with
 292 * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
 293 *
 294 * This is called with the siglock held, to decide whether or not it's
 295 * necessary to release the siglock and call arch_ptrace_stop() with the
 296 * same @code and @info arguments.  It can be defined to a constant if
 297 * arch_ptrace_stop() is never required, or always is.  On machines where
 298 * this makes sense, it should be defined to a quick test to optimize out
 299 * calling arch_ptrace_stop() when it would be superfluous.  For example,
 300 * if the thread has not been back to user mode since the last stop, the
 301 * thread state might indicate that nothing needs to be done.
 302 */
 303#define arch_ptrace_stop_needed(code, info)     (0)
 304#endif
 305
 306#ifndef arch_ptrace_stop
 307/**
 308 * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
 309 * @code:       current->exit_code value ptrace will stop with
 310 * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
 311 *
 312 * This is called with no locks held when arch_ptrace_stop_needed() has
 313 * just returned nonzero.  It is allowed to block, e.g. for user memory
 314 * access.  The arch can have machine-specific work to be done before
 315 * ptrace stops.  On ia64, register backing store gets written back to user
 316 * memory here.  Since this can be costly (requires dropping the siglock),
 317 * we only do it when the arch requires it for this particular stop, as
 318 * indicated by arch_ptrace_stop_needed().
 319 */
 320#define arch_ptrace_stop(code, info)            do { } while (0)
 321#endif
 322
 323#ifndef arch_ptrace_untrace
 324/*
 325 * Do machine-specific work before untracing child.
 326 *
 327 * This is called for a normal detach as well as from ptrace_exit()
 328 * when the tracing task dies.
 329 *
 330 * Called with write_lock(&tasklist_lock) held.
 331 */
 332#define arch_ptrace_untrace(task)               do { } while (0)
 333#endif
 334
 335extern int task_current_syscall(struct task_struct *target, long *callno,
 336                                unsigned long args[6], unsigned int maxargs,
 337                                unsigned long *sp, unsigned long *pc);
 338
 339#endif
 340
 341#endif
 342
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