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_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
 106 extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
 107 extern void ptrace_disable(struct task_struct *);
 108 extern int ptrace_check_attach(struct task_struct *task, int kill);
 109 extern int ptrace_request(struct task_struct *child, long request,
 110                           unsigned long addr, unsigned long data);
 111 extern void ptrace_notify(int exit_code);
 112 extern void __ptrace_link(struct task_struct *child,
 113                           struct task_struct *new_parent);
 114 extern void __ptrace_unlink(struct task_struct *child);
 115 extern void exit_ptrace(struct task_struct *tracer);
 116 #define PTRACE_MODE_READ   1
 117 #define PTRACE_MODE_ATTACH 2
 118 /* Returns 0 on success, -errno on denial. */
 119 extern int __ptrace_may_access(struct task_struct *task, unsigned int mode);
 120 /* Returns true on success, false on denial. */
 121 extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
 122
 123 static inline int ptrace_reparented(struct task_struct *child)
 124 {
 125         return child->real_parent != child->parent;
 126 }
 127
 128 static inline void ptrace_unlink(struct task_struct *child)
 129 {
 130         if (unlikely(child->ptrace))
 131                 __ptrace_unlink(child);
 132 }
 133
 134 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
 135                             unsigned long data);
 136 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
 137                             unsigned long data);
 138
 139 /**
 140  * task_ptrace - return %PT_* flags that apply to a task
 141  * @task:       pointer to &task_struct in question
 142  *
 143  * Returns the %PT_* flags that apply to @task.
 144  */
 145 static inline int task_ptrace(struct task_struct *task)
 146 {
 147         return task->ptrace;
 148 }
 149
 150 /**
 151  * ptrace_event - possibly stop for a ptrace event notification
 152  * @mask:       %PT_* bit to check in @current->ptrace
 153  * @event:      %PTRACE_EVENT_* value to report if @mask is set
 154  * @message:    value for %PTRACE_GETEVENTMSG to return
 155  *
 156  * This checks the @mask bit to see if ptrace wants stops for this event.
 157  * If so we stop, reporting @event and @message to the ptrace parent.
 158  *
 159  * Returns nonzero if we did a ptrace notification, zero if not.
 160  *
 161  * Called without locks.
 162  */
 163 static inline int ptrace_event(int mask, int event, unsigned long message)
 164 {
 165         if (mask && likely(!(current->ptrace & mask)))
 166                 return 0;
 167         current->ptrace_message = message;
 168         ptrace_notify((event << 8) | SIGTRAP);
 169         return 1;
 170 }
 171
 172 /**
 173  * ptrace_init_task - initialize ptrace state for a new child
 174  * @child:              new child task
 175  * @ptrace:             true if child should be ptrace'd by parent's tracer
 176  *
 177  * This is called immediately after adding @child to its parent's children
 178  * list.  @ptrace is false in the normal case, and true to ptrace @child.
 179  *
 180  * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
 181  */
 182 static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
 183 {
 184         INIT_LIST_HEAD(&child->ptrace_entry);
 185         INIT_LIST_HEAD(&child->ptraced);
 186         child->parent = child->real_parent;
 187         child->ptrace = 0;
 188         if (unlikely(ptrace) && (current->ptrace & PT_PTRACED)) {
 189                 child->ptrace = current->ptrace;
 190                 __ptrace_link(child, current->parent);
 191         }
 192
 193 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 194         atomic_set(&child->ptrace_bp_refcnt, 1);
 195 #endif
 196 }
 197
 198 /**
 199  * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
 200  * @task:       task in %EXIT_DEAD state
 201  *
 202  * Called with write_lock(&tasklist_lock) held.
 203  */
 204 static inline void ptrace_release_task(struct task_struct *task)
 205 {
 206         BUG_ON(!list_empty(&task->ptraced));
 207         ptrace_unlink(task);
 208         BUG_ON(!list_empty(&task->ptrace_entry));
 209 }
 210
 211 #ifndef force_successful_syscall_return
 212 /*
 213  * System call handlers that, upon successful completion, need to return a
 214  * negative value should call force_successful_syscall_return() right before
 215  * returning.  On architectures where the syscall convention provides for a
 216  * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
 217  * others), this macro can be used to ensure that the error flag will not get
 218  * set.  On architectures which do not support a separate error flag, the macro
 219  * is a no-op and the spurious error condition needs to be filtered out by some
 220  * other means (e.g., in user-level, by passing an extra argument to the
 221  * syscall handler, or something along those lines).
 222  */
 223 #define force_successful_syscall_return() do { } while (0)
 224 #endif
 225
 226 /*
 227  * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
 228  *
 229  * These do-nothing inlines are used when the arch does not
 230  * implement single-step.  The kerneldoc comments are here
 231  * to document the interface for all arch definitions.
 232  */
 233
 234 #ifndef arch_has_single_step
 235 /**
 236  * arch_has_single_step - does this CPU support user-mode single-step?
 237  *
 238  * If this is defined, then there must be function declarations or
 239  * inlines for user_enable_single_step() and user_disable_single_step().
 240  * arch_has_single_step() should evaluate to nonzero iff the machine
 241  * supports instruction single-step for user mode.
 242  * It can be a constant or it can test a CPU feature bit.
 243  */
 244 #define arch_has_single_step()          (0)
 245
 246 /**
 247  * user_enable_single_step - single-step in user-mode task
 248  * @task: either current or a task stopped in %TASK_TRACED
 249  *
 250  * This can only be called when arch_has_single_step() has returned nonzero.
 251  * Set @task so that when it returns to user mode, it will trap after the
 252  * next single instruction executes.  If arch_has_block_step() is defined,
 253  * this must clear the effects of user_enable_block_step() too.
 254  */
 255 static inline void user_enable_single_step(struct task_struct *task)
 256 {
 257         BUG();                  /* This can never be called.  */
 258 }
 259
 260 /**
 261  * user_disable_single_step - cancel user-mode single-step
 262  * @task: either current or a task stopped in %TASK_TRACED
 263  *
 264  * Clear @task of the effects of user_enable_single_step() and
 265  * user_enable_block_step().  This can be called whether or not either
 266  * of those was ever called on @task, and even if arch_has_single_step()
 267  * returned zero.
 268  */
 269 static inline void user_disable_single_step(struct task_struct *task)
 270 {
 271 }
 272 #else
 273 extern void user_enable_single_step(struct task_struct *);
 274 extern void user_disable_single_step(struct task_struct *);
 275 #endif  /* arch_has_single_step */
 276
 277 #ifndef arch_has_block_step
 278 /**
 279  * arch_has_block_step - does this CPU support user-mode block-step?
 280  *
 281  * If this is defined, then there must be a function declaration or inline
 282  * for user_enable_block_step(), and arch_has_single_step() must be defined
 283  * too.  arch_has_block_step() should evaluate to nonzero iff the machine
 284  * supports step-until-branch for user mode.  It can be a constant or it
 285  * can test a CPU feature bit.
 286  */
 287 #define arch_has_block_step()           (0)
 288
 289 /**
 290  * user_enable_block_step - step until branch in user-mode task
 291  * @task: either current or a task stopped in %TASK_TRACED
 292  *
 293  * This can only be called when arch_has_block_step() has returned nonzero,
 294  * and will never be called when single-instruction stepping is being used.
 295  * Set @task so that when it returns to user mode, it will trap after the
 296  * next branch or trap taken.
 297  */
 298 static inline void user_enable_block_step(struct task_struct *task)
 299 {
 300         BUG();                  /* This can never be called.  */
 301 }
 302 #else
 303 extern void user_enable_block_step(struct task_struct *);
 304 #endif  /* arch_has_block_step */
 305
 306 #ifdef ARCH_HAS_USER_SINGLE_STEP_INFO
 307 extern void user_single_step_siginfo(struct task_struct *tsk,
 308                                 struct pt_regs *regs, siginfo_t *info);
 309 #else
 310 static inline void user_single_step_siginfo(struct task_struct *tsk,
 311                                 struct pt_regs *regs, siginfo_t *info)
 312 {
 313         memset(info, 0, sizeof(*info));
 314         info->si_signo = SIGTRAP;
 315 }
 316 #endif
 317
 318 #ifndef arch_ptrace_stop_needed
 319 /**
 320  * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
 321  * @code:       current->exit_code value ptrace will stop with
 322  * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
 323  *
 324  * This is called with the siglock held, to decide whether or not it's
 325  * necessary to release the siglock and call arch_ptrace_stop() with the
 326  * same @code and @info arguments.  It can be defined to a constant if
 327  * arch_ptrace_stop() is never required, or always is.  On machines where
 328  * this makes sense, it should be defined to a quick test to optimize out
 329  * calling arch_ptrace_stop() when it would be superfluous.  For example,
 330  * if the thread has not been back to user mode since the last stop, the
 331  * thread state might indicate that nothing needs to be done.
 332  */
 333 #define arch_ptrace_stop_needed(code, info)     (0)
 334 #endif
 335
 336 #ifndef arch_ptrace_stop
 337 /**
 338  * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
 339  * @code:       current->exit_code value ptrace will stop with
 340  * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
 341  *
 342  * This is called with no locks held when arch_ptrace_stop_needed() has
 343  * just returned nonzero.  It is allowed to block, e.g. for user memory
 344  * access.  The arch can have machine-specific work to be done before
 345  * ptrace stops.  On ia64, register backing store gets written back to user
 346  * memory here.  Since this can be costly (requires dropping the siglock),
 347  * we only do it when the arch requires it for this particular stop, as
 348  * indicated by arch_ptrace_stop_needed().
 349  */
 350 #define arch_ptrace_stop(code, info)            do { } while (0)
 351 #endif
 352
 353 extern int task_current_syscall(struct task_struct *target, long *callno,
 354                                 unsigned long args[6], unsigned int maxargs,
 355                                 unsigned long *sp, unsigned long *pc);
 356
 357 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 358 extern int ptrace_get_breakpoints(struct task_struct *tsk);
 359 extern void ptrace_put_breakpoints(struct task_struct *tsk);
 360 #else
 361 static inline void ptrace_put_breakpoints(struct task_struct *tsk) { }
 362 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 363
 364 #endif /* __KERNEL */
 365
 366 #endif