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 /* options set using PTRACE_SETOPTIONS */
  51 #define PTRACE_O_TRACESYSGOOD   0x00000001
  52 #define PTRACE_O_TRACEFORK      0x00000002
  53 #define PTRACE_O_TRACEVFORK     0x00000004
  54 #define PTRACE_O_TRACECLONE     0x00000008
  55 #define PTRACE_O_TRACEEXEC      0x00000010
  56 #define PTRACE_O_TRACEVFORKDONE 0x00000020
  57 #define PTRACE_O_TRACEEXIT      0x00000040
  58
  59 #define PTRACE_O_MASK           0x0000007f
  60
  61 /* Wait extended result codes for the above trace options.  */
  62 #define PTRACE_EVENT_FORK       1
  63 #define PTRACE_EVENT_VFORK      2
  64 #define PTRACE_EVENT_CLONE      3
  65 #define PTRACE_EVENT_EXEC       4
  66 #define PTRACE_EVENT_VFORK_DONE 5
  67 #define PTRACE_EVENT_EXIT       6
  68
  69 #include <asm/ptrace.h>
  70
  71 #ifdef __KERNEL__
  72 /*
  73  * Ptrace flags
  74  *
  75  * The owner ship rules for task->ptrace which holds the ptrace
  76  * flags is simple.  When a task is running it owns it's task->ptrace
  77  * flags.  When the a task is stopped the ptracer owns task->ptrace.
  78  */
  79
  80 #define PT_PTRACED      0x00000001
  81 #define PT_DTRACE       0x00000002      /* delayed trace (used on m68k, i386) */
  82 #define PT_TRACESYSGOOD 0x00000004
  83 #define PT_PTRACE_CAP   0x00000008      /* ptracer can follow suid-exec */
  84 #define PT_TRACE_FORK   0x00000010
  85 #define PT_TRACE_VFORK  0x00000020
  86 #define PT_TRACE_CLONE  0x00000040
  87 #define PT_TRACE_EXEC   0x00000080
  88 #define PT_TRACE_VFORK_DONE     0x00000100
  89 #define PT_TRACE_EXIT   0x00000200
  90
  91 #define PT_TRACE_MASK   0x000003f4
  92
  93 /* single stepping state bits (used on ARM and PA-RISC) */
  94 #define PT_SINGLESTEP_BIT       31
  95 #define PT_SINGLESTEP           (1<<PT_SINGLESTEP_BIT)
  96 #define PT_BLOCKSTEP_BIT        30
  97 #define PT_BLOCKSTEP            (1<<PT_BLOCKSTEP_BIT)
  98
  99 #include <linux/compiler.h>             /* For unlikely.  */
 100 #include <linux/sched.h>                /* For struct task_struct.  */
 101
 102
 103 extern long arch_ptrace(struct task_struct *child, long request,
 104                         unsigned long addr, unsigned long data);
 105 extern int ptrace_traceme(void);
 106 extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
 107 extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
 108 extern int ptrace_attach(struct task_struct *tsk);
 109 extern int ptrace_detach(struct task_struct *, unsigned int);
 110 extern void ptrace_disable(struct task_struct *);
 111 extern int ptrace_check_attach(struct task_struct *task, int kill);
 112 extern int ptrace_request(struct task_struct *child, long request,
 113                           unsigned long addr, unsigned long data);
 114 extern void ptrace_notify(int exit_code);
 115 extern void __ptrace_link(struct task_struct *child,
 116                           struct task_struct *new_parent);
 117 extern void __ptrace_unlink(struct task_struct *child);
 118 extern void exit_ptrace(struct task_struct *tracer);
 119 #define PTRACE_MODE_READ   1
 120 #define PTRACE_MODE_ATTACH 2
 121 /* Returns 0 on success, -errno on denial. */
 122 extern int __ptrace_may_access(struct task_struct *task, unsigned int mode);
 123 /* Returns true on success, false on denial. */
 124 extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
 125
 126 static inline int ptrace_reparented(struct task_struct *child)
 127 {
 128         return child->real_parent != child->parent;
 129 }
 130
 131 static inline void ptrace_unlink(struct task_struct *child)
 132 {
 133         if (unlikely(child->ptrace))
 134                 __ptrace_unlink(child);
 135 }
 136
 137 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
 138                             unsigned long data);
 139 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
 140                             unsigned long data);
 141
 142 /**
 143  * task_ptrace - return %PT_* flags that apply to a task
 144  * @task:       pointer to &task_struct in question
 145  *
 146  * Returns the %PT_* flags that apply to @task.
 147  */
 148 static inline int task_ptrace(struct task_struct *task)
 149 {
 150         return task->ptrace;
 151 }
 152
 153 /**
 154  * ptrace_event - possibly stop for a ptrace event notification
 155  * @mask:       %PT_* bit to check in @current->ptrace
 156  * @event:      %PTRACE_EVENT_* value to report if @mask is set
 157  * @message:    value for %PTRACE_GETEVENTMSG to return
 158  *
 159  * This checks the @mask bit to see if ptrace wants stops for this event.
 160  * If so we stop, reporting @event and @message to the ptrace parent.
 161  *
 162  * Returns nonzero if we did a ptrace notification, zero if not.
 163  *
 164  * Called without locks.
 165  */
 166 static inline int ptrace_event(int mask, int event, unsigned long message)
 167 {
 168         if (mask && likely(!(current->ptrace & mask)))
 169                 return 0;
 170         current->ptrace_message = message;
 171         ptrace_notify((event << 8) | SIGTRAP);
 172         return 1;
 173 }
 174
 175 /**
 176  * ptrace_init_task - initialize ptrace state for a new child
 177  * @child:              new child task
 178  * @ptrace:             true if child should be ptrace'd by parent's tracer
 179  *
 180  * This is called immediately after adding @child to its parent's children
 181  * list.  @ptrace is false in the normal case, and true to ptrace @child.
 182  *
 183  * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
 184  */
 185 static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
 186 {
 187         INIT_LIST_HEAD(&child->ptrace_entry);
 188         INIT_LIST_HEAD(&child->ptraced);
 189         child->parent = child->real_parent;
 190         child->ptrace = 0;
 191         if (unlikely(ptrace) && (current->ptrace & PT_PTRACED)) {
 192                 child->ptrace = current->ptrace;
 193                 __ptrace_link(child, current->parent);
 194         }
 195 }
 196
 197 /**
 198  * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
 199  * @task:       task in %EXIT_DEAD state
 200  *
 201  * Called with write_lock(&tasklist_lock) held.
 202  */
 203 static inline void ptrace_release_task(struct task_struct *task)
 204 {
 205         BUG_ON(!list_empty(&task->ptraced));
 206         ptrace_unlink(task);
 207         BUG_ON(!list_empty(&task->ptrace_entry));
 208 }
 209
 210 #ifndef force_successful_syscall_return
 211 /*
 212  * System call handlers that, upon successful completion, need to return a
 213  * negative value should call force_successful_syscall_return() right before
 214  * returning.  On architectures where the syscall convention provides for a
 215  * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
 216  * others), this macro can be used to ensure that the error flag will not get
 217  * set.  On architectures which do not support a separate error flag, the macro
 218  * is a no-op and the spurious error condition needs to be filtered out by some
 219  * other means (e.g., in user-level, by passing an extra argument to the
 220  * syscall handler, or something along those lines).
 221  */
 222 #define force_successful_syscall_return() do { } while (0)
 223 #endif
 224
 225 /*
 226  * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
 227  *
 228  * These do-nothing inlines are used when the arch does not
 229  * implement single-step.  The kerneldoc comments are here
 230  * to document the interface for all arch definitions.
 231  */
 232
 233 #ifndef arch_has_single_step
 234 /**
 235  * arch_has_single_step - does this CPU support user-mode single-step?
 236  *
 237  * If this is defined, then there must be function declarations or
 238  * inlines for user_enable_single_step() and user_disable_single_step().
 239  * arch_has_single_step() should evaluate to nonzero iff the machine
 240  * supports instruction single-step for user mode.
 241  * It can be a constant or it can test a CPU feature bit.
 242  */
 243 #define arch_has_single_step()          (0)
 244
 245 /**
 246  * user_enable_single_step - single-step in user-mode task
 247  * @task: either current or a task stopped in %TASK_TRACED
 248  *
 249  * This can only be called when arch_has_single_step() has returned nonzero.
 250  * Set @task so that when it returns to user mode, it will trap after the
 251  * next single instruction executes.  If arch_has_block_step() is defined,
 252  * this must clear the effects of user_enable_block_step() too.
 253  */
 254 static inline void user_enable_single_step(struct task_struct *task)
 255 {
 256         BUG();                  /* This can never be called.  */
 257 }
 258
 259 /**
 260  * user_disable_single_step - cancel user-mode single-step
 261  * @task: either current or a task stopped in %TASK_TRACED
 262  *
 263  * Clear @task of the effects of user_enable_single_step() and
 264  * user_enable_block_step().  This can be called whether or not either
 265  * of those was ever called on @task, and even if arch_has_single_step()
 266  * returned zero.
 267  */
 268 static inline void user_disable_single_step(struct task_struct *task)
 269 {
 270 }
 271 #else
 272 extern void user_enable_single_step(struct task_struct *);
 273 extern void user_disable_single_step(struct task_struct *);
 274 #endif  /* arch_has_single_step */
 275
 276 #ifndef arch_has_block_step
 277 /**
 278  * arch_has_block_step - does this CPU support user-mode block-step?
 279  *
 280  * If this is defined, then there must be a function declaration or inline
 281  * for user_enable_block_step(), and arch_has_single_step() must be defined
 282  * too.  arch_has_block_step() should evaluate to nonzero iff the machine
 283  * supports step-until-branch for user mode.  It can be a constant or it
 284  * can test a CPU feature bit.
 285  */
 286 #define arch_has_block_step()           (0)
 287
 288 /**
 289  * user_enable_block_step - step until branch in user-mode task
 290  * @task: either current or a task stopped in %TASK_TRACED
 291  *
 292  * This can only be called when arch_has_block_step() has returned nonzero,
 293  * and will never be called when single-instruction stepping is being used.
 294  * Set @task so that when it returns to user mode, it will trap after the
 295  * next branch or trap taken.
 296  */
 297 static inline void user_enable_block_step(struct task_struct *task)
 298 {
 299         BUG();                  /* This can never be called.  */
 300 }
 301 #else
 302 extern void user_enable_block_step(struct task_struct *);
 303 #endif  /* arch_has_block_step */
 304
 305 #ifdef ARCH_HAS_USER_SINGLE_STEP_INFO
 306 extern void user_single_step_siginfo(struct task_struct *tsk,
 307                                 struct pt_regs *regs, siginfo_t *info);
 308 #else
 309 static inline void user_single_step_siginfo(struct task_struct *tsk,
 310                                 struct pt_regs *regs, siginfo_t *info)
 311 {
 312         memset(info, 0, sizeof(*info));
 313         info->si_signo = SIGTRAP;
 314 }
 315 #endif
 316
 317 #ifndef arch_ptrace_stop_needed
 318 /**
 319  * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
 320  * @code:       current->exit_code value ptrace will stop with
 321  * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
 322  *
 323  * This is called with the siglock held, to decide whether or not it's
 324  * necessary to release the siglock and call arch_ptrace_stop() with the
 325  * same @code and @info arguments.  It can be defined to a constant if
 326  * arch_ptrace_stop() is never required, or always is.  On machines where
 327  * this makes sense, it should be defined to a quick test to optimize out
 328  * calling arch_ptrace_stop() when it would be superfluous.  For example,
 329  * if the thread has not been back to user mode since the last stop, the
 330  * thread state might indicate that nothing needs to be done.
 331  */
 332 #define arch_ptrace_stop_needed(code, info)     (0)
 333 #endif
 334
 335 #ifndef arch_ptrace_stop
 336 /**
 337  * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
 338  * @code:       current->exit_code value ptrace will stop with
 339  * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
 340  *
 341  * This is called with no locks held when arch_ptrace_stop_needed() has
 342  * just returned nonzero.  It is allowed to block, e.g. for user memory
 343  * access.  The arch can have machine-specific work to be done before
 344  * ptrace stops.  On ia64, register backing store gets written back to user
 345  * memory here.  Since this can be costly (requires dropping the siglock),
 346  * we only do it when the arch requires it for this particular stop, as
 347  * indicated by arch_ptrace_stop_needed().
 348  */
 349 #define arch_ptrace_stop(code, info)            do { } while (0)
 350 #endif
 351
 352 extern int task_current_syscall(struct task_struct *target, long *callno,
 353                                 unsigned long args[6], unsigned int maxargs,
 354                                 unsigned long *sp, unsigned long *pc);
 355
 356 #endif
 357
 358 #endif