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 #define PTRACE_SEIZE            0x4206
  51 #define PTRACE_INTERRUPT        0x4207
  52 #define PTRACE_LISTEN           0x4208
  53
  54 /* flags in @data for PTRACE_SEIZE */
  55 #define PTRACE_SEIZE_DEVEL      0x80000000 /* temp flag for development */
  56
  57 /* options set using PTRACE_SETOPTIONS */
  58 #define PTRACE_O_TRACESYSGOOD   0x00000001
  59 #define PTRACE_O_TRACEFORK      0x00000002
  60 #define PTRACE_O_TRACEVFORK     0x00000004
  61 #define PTRACE_O_TRACECLONE     0x00000008
  62 #define PTRACE_O_TRACEEXEC      0x00000010
  63 #define PTRACE_O_TRACEVFORKDONE 0x00000020
  64 #define PTRACE_O_TRACEEXIT      0x00000040
  65
  66 #define PTRACE_O_MASK           0x0000007f
  67
  68 /* Wait extended result codes for the above trace options.  */
  69 #define PTRACE_EVENT_FORK       1
  70 #define PTRACE_EVENT_VFORK      2
  71 #define PTRACE_EVENT_CLONE      3
  72 #define PTRACE_EVENT_EXEC       4
  73 #define PTRACE_EVENT_VFORK_DONE 5
  74 #define PTRACE_EVENT_EXIT       6
  75 #define PTRACE_EVENT_STOP       7
  76
  77 #include <asm/ptrace.h>
  78
  79 #ifdef __KERNEL__
  80 /*
  81  * Ptrace flags
  82  *
  83  * The owner ship rules for task->ptrace which holds the ptrace
  84  * flags is simple.  When a task is running it owns it's task->ptrace
  85  * flags.  When the a task is stopped the ptracer owns task->ptrace.
  86  */
  87
  88 #define PT_SEIZED       0x00010000      /* SEIZE used, enable new behavior */
  89 #define PT_PTRACED      0x00000001
  90 #define PT_DTRACE       0x00000002      /* delayed trace (used on m68k, i386) */
  91 #define PT_TRACESYSGOOD 0x00000004
  92 #define PT_PTRACE_CAP   0x00000008      /* ptracer can follow suid-exec */
  93 #define PT_TRACE_FORK   0x00000010
  94 #define PT_TRACE_VFORK  0x00000020
  95 #define PT_TRACE_CLONE  0x00000040
  96 #define PT_TRACE_EXEC   0x00000080
  97 #define PT_TRACE_VFORK_DONE     0x00000100
  98 #define PT_TRACE_EXIT   0x00000200
  99
 100 #define PT_TRACE_MASK   0x000003f4
 101
 102 /* single stepping state bits (used on ARM and PA-RISC) */
 103 #define PT_SINGLESTEP_BIT       31
 104 #define PT_SINGLESTEP           (1<<PT_SINGLESTEP_BIT)
 105 #define PT_BLOCKSTEP_BIT        30
 106 #define PT_BLOCKSTEP            (1<<PT_BLOCKSTEP_BIT)
 107
 108 #include <linux/compiler.h>             /* For unlikely.  */
 109 #include <linux/sched.h>                /* For struct task_struct.  */
 110
 111
 112 extern long arch_ptrace(struct task_struct *child, long request,
 113                         unsigned long addr, unsigned long data);
 114 extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
 115 extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
 116 extern void ptrace_disable(struct task_struct *);
 117 extern int ptrace_check_attach(struct task_struct *task, bool ignore_state);
 118 extern int ptrace_request(struct task_struct *child, long request,
 119                           unsigned long addr, unsigned long data);
 120 extern void ptrace_notify(int exit_code);
 121 extern void __ptrace_link(struct task_struct *child,
 122                           struct task_struct *new_parent);
 123 extern void __ptrace_unlink(struct task_struct *child);
 124 extern void exit_ptrace(struct task_struct *tracer);
 125 #define PTRACE_MODE_READ   1
 126 #define PTRACE_MODE_ATTACH 2
 127 /* Returns 0 on success, -errno on denial. */
 128 extern int __ptrace_may_access(struct task_struct *task, unsigned int mode);
 129 /* Returns true on success, false on denial. */
 130 extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
 131
 132 static inline int ptrace_reparented(struct task_struct *child)
 133 {
 134         return child->real_parent != child->parent;
 135 }
 136
 137 static inline void ptrace_unlink(struct task_struct *child)
 138 {
 139         if (unlikely(child->ptrace))
 140                 __ptrace_unlink(child);
 141 }
 142
 143 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
 144                             unsigned long data);
 145 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
 146                             unsigned long data);
 147
 148 /**
 149  * task_ptrace - return %PT_* flags that apply to a task
 150  * @task:       pointer to &task_struct in question
 151  *
 152  * Returns the %PT_* flags that apply to @task.
 153  */
 154 static inline int task_ptrace(struct task_struct *task)
 155 {
 156         return task->ptrace;
 157 }
 158
 159 /**
 160  * ptrace_event - possibly stop for a ptrace event notification
 161  * @mask:       %PT_* bit to check in @current->ptrace
 162  * @event:      %PTRACE_EVENT_* value to report if @mask is set
 163  * @message:    value for %PTRACE_GETEVENTMSG to return
 164  *
 165  * This checks the @mask bit to see if ptrace wants stops for this event.
 166  * If so we stop, reporting @event and @message to the ptrace parent.
 167  *
 168  * Returns nonzero if we did a ptrace notification, zero if not.
 169  *
 170  * Called without locks.
 171  */
 172 static inline int ptrace_event(int mask, int event, unsigned long message)
 173 {
 174         if (mask && likely(!(current->ptrace & mask)))
 175                 return 0;
 176         current->ptrace_message = message;
 177         ptrace_notify((event << 8) | SIGTRAP);
 178         return 1;
 179 }
 180
 181 /**
 182  * ptrace_init_task - initialize ptrace state for a new child
 183  * @child:              new child task
 184  * @ptrace:             true if child should be ptrace'd by parent's tracer
 185  *
 186  * This is called immediately after adding @child to its parent's children
 187  * list.  @ptrace is false in the normal case, and true to ptrace @child.
 188  *
 189  * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
 190  */
 191 static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
 192 {
 193         INIT_LIST_HEAD(&child->ptrace_entry);
 194         INIT_LIST_HEAD(&child->ptraced);
 195         child->parent = child->real_parent;
 196         child->ptrace = 0;
 197         if (unlikely(ptrace) && (current->ptrace & PT_PTRACED)) {
 198                 child->ptrace = current->ptrace;
 199                 __ptrace_link(child, current->parent);
 200         }
 201
 202 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 203         atomic_set(&child->ptrace_bp_refcnt, 1);
 204 #endif
 205 }
 206
 207 /**
 208  * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
 209  * @task:       task in %EXIT_DEAD state
 210  *
 211  * Called with write_lock(&tasklist_lock) held.
 212  */
 213 static inline void ptrace_release_task(struct task_struct *task)
 214 {
 215         BUG_ON(!list_empty(&task->ptraced));
 216         ptrace_unlink(task);
 217         BUG_ON(!list_empty(&task->ptrace_entry));
 218 }
 219
 220 #ifndef force_successful_syscall_return
 221 /*
 222  * System call handlers that, upon successful completion, need to return a
 223  * negative value should call force_successful_syscall_return() right before
 224  * returning.  On architectures where the syscall convention provides for a
 225  * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
 226  * others), this macro can be used to ensure that the error flag will not get
 227  * set.  On architectures which do not support a separate error flag, the macro
 228  * is a no-op and the spurious error condition needs to be filtered out by some
 229  * other means (e.g., in user-level, by passing an extra argument to the
 230  * syscall handler, or something along those lines).
 231  */
 232 #define force_successful_syscall_return() do { } while (0)
 233 #endif
 234
 235 /*
 236  * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
 237  *
 238  * These do-nothing inlines are used when the arch does not
 239  * implement single-step.  The kerneldoc comments are here
 240  * to document the interface for all arch definitions.
 241  */
 242
 243 #ifndef arch_has_single_step
 244 /**
 245  * arch_has_single_step - does this CPU support user-mode single-step?
 246  *
 247  * If this is defined, then there must be function declarations or
 248  * inlines for user_enable_single_step() and user_disable_single_step().
 249  * arch_has_single_step() should evaluate to nonzero iff the machine
 250  * supports instruction single-step for user mode.
 251  * It can be a constant or it can test a CPU feature bit.
 252  */
 253 #define arch_has_single_step()          (0)
 254
 255 /**
 256  * user_enable_single_step - single-step in user-mode task
 257  * @task: either current or a task stopped in %TASK_TRACED
 258  *
 259  * This can only be called when arch_has_single_step() has returned nonzero.
 260  * Set @task so that when it returns to user mode, it will trap after the
 261  * next single instruction executes.  If arch_has_block_step() is defined,
 262  * this must clear the effects of user_enable_block_step() too.
 263  */
 264 static inline void user_enable_single_step(struct task_struct *task)
 265 {
 266         BUG();                  /* This can never be called.  */
 267 }
 268
 269 /**
 270  * user_disable_single_step - cancel user-mode single-step
 271  * @task: either current or a task stopped in %TASK_TRACED
 272  *
 273  * Clear @task of the effects of user_enable_single_step() and
 274  * user_enable_block_step().  This can be called whether or not either
 275  * of those was ever called on @task, and even if arch_has_single_step()
 276  * returned zero.
 277  */
 278 static inline void user_disable_single_step(struct task_struct *task)
 279 {
 280 }
 281 #else
 282 extern void user_enable_single_step(struct task_struct *);
 283 extern void user_disable_single_step(struct task_struct *);
 284 #endif  /* arch_has_single_step */
 285
 286 #ifndef arch_has_block_step
 287 /**
 288  * arch_has_block_step - does this CPU support user-mode block-step?
 289  *
 290  * If this is defined, then there must be a function declaration or inline
 291  * for user_enable_block_step(), and arch_has_single_step() must be defined
 292  * too.  arch_has_block_step() should evaluate to nonzero iff the machine
 293  * supports step-until-branch for user mode.  It can be a constant or it
 294  * can test a CPU feature bit.
 295  */
 296 #define arch_has_block_step()           (0)
 297
 298 /**
 299  * user_enable_block_step - step until branch in user-mode task
 300  * @task: either current or a task stopped in %TASK_TRACED
 301  *
 302  * This can only be called when arch_has_block_step() has returned nonzero,
 303  * and will never be called when single-instruction stepping is being used.
 304  * Set @task so that when it returns to user mode, it will trap after the
 305  * next branch or trap taken.
 306  */
 307 static inline void user_enable_block_step(struct task_struct *task)
 308 {
 309         BUG();                  /* This can never be called.  */
 310 }
 311 #else
 312 extern void user_enable_block_step(struct task_struct *);
 313 #endif  /* arch_has_block_step */
 314
 315 #ifdef ARCH_HAS_USER_SINGLE_STEP_INFO
 316 extern void user_single_step_siginfo(struct task_struct *tsk,
 317                                 struct pt_regs *regs, siginfo_t *info);
 318 #else
 319 static inline void user_single_step_siginfo(struct task_struct *tsk,
 320                                 struct pt_regs *regs, siginfo_t *info)
 321 {
 322         memset(info, 0, sizeof(*info));
 323         info->si_signo = SIGTRAP;
 324 }
 325 #endif
 326
 327 #ifndef arch_ptrace_stop_needed
 328 /**
 329  * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
 330  * @code:       current->exit_code value ptrace will stop with
 331  * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
 332  *
 333  * This is called with the siglock held, to decide whether or not it's
 334  * necessary to release the siglock and call arch_ptrace_stop() with the
 335  * same @code and @info arguments.  It can be defined to a constant if
 336  * arch_ptrace_stop() is never required, or always is.  On machines where
 337  * this makes sense, it should be defined to a quick test to optimize out
 338  * calling arch_ptrace_stop() when it would be superfluous.  For example,
 339  * if the thread has not been back to user mode since the last stop, the
 340  * thread state might indicate that nothing needs to be done.
 341  */
 342 #define arch_ptrace_stop_needed(code, info)     (0)
 343 #endif
 344
 345 #ifndef arch_ptrace_stop
 346 /**
 347  * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
 348  * @code:       current->exit_code value ptrace will stop with
 349  * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
 350  *
 351  * This is called with no locks held when arch_ptrace_stop_needed() has
 352  * just returned nonzero.  It is allowed to block, e.g. for user memory
 353  * access.  The arch can have machine-specific work to be done before
 354  * ptrace stops.  On ia64, register backing store gets written back to user
 355  * memory here.  Since this can be costly (requires dropping the siglock),
 356  * we only do it when the arch requires it for this particular stop, as
 357  * indicated by arch_ptrace_stop_needed().
 358  */
 359 #define arch_ptrace_stop(code, info)            do { } while (0)
 360 #endif
 361
 362 extern int task_current_syscall(struct task_struct *target, long *callno,
 363                                 unsigned long args[6], unsigned int maxargs,
 364                                 unsigned long *sp, unsigned long *pc);
 365
 366 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 367 extern int ptrace_get_breakpoints(struct task_struct *tsk);
 368 extern void ptrace_put_breakpoints(struct task_struct *tsk);
 369 #else
 370 static inline void ptrace_put_breakpoints(struct task_struct *tsk) { }
 371 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 372
 373 #endif /* __KERNEL */
 374
 375 #endif