gdb/nat/linux-ptrace.h

   1 /* Copyright (C) 2011-2015 Free Software Foundation, Inc.
   2
   3    This file is part of GDB.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18 #ifndef COMMON_LINUX_PTRACE_H
  19 #define COMMON_LINUX_PTRACE_H
  20
  21 struct buffer;
  22
  23 #include <sys/ptrace.h>
  24
  25 #ifdef __UCLIBC__
  26 #if !(defined(__UCLIBC_HAS_MMU__) || defined(__ARCH_HAS_MMU__))
  27 /* PTRACE_TEXT_ADDR and friends.  */
  28 #include <asm/ptrace.h>
  29 #define HAS_NOMMU
  30 #endif
  31 #endif
  32
  33 #if !defined(PTRACE_TYPE_ARG3)
  34 #define PTRACE_TYPE_ARG3 void *
  35 #endif
  36
  37 #if !defined(PTRACE_TYPE_ARG4)
  38 #define PTRACE_TYPE_ARG4 void *
  39 #endif
  40
  41 #ifndef PTRACE_GETSIGINFO
  42 # define PTRACE_GETSIGINFO 0x4202
  43 # define PTRACE_SETSIGINFO 0x4203
  44 #endif /* PTRACE_GETSIGINF */
  45
  46 /* If the system headers did not provide the constants, hard-code the normal
  47    values.  */
  48 #ifndef PTRACE_EVENT_FORK
  49
  50 #define PTRACE_SETOPTIONS       0x4200
  51 #define PTRACE_GETEVENTMSG      0x4201
  52
  53 /* options set using PTRACE_SETOPTIONS */
  54 #define PTRACE_O_TRACESYSGOOD   0x00000001
  55 #define PTRACE_O_TRACEFORK      0x00000002
  56 #define PTRACE_O_TRACEVFORK     0x00000004
  57 #define PTRACE_O_TRACECLONE     0x00000008
  58 #define PTRACE_O_TRACEEXEC      0x00000010
  59 #define PTRACE_O_TRACEVFORKDONE 0x00000020
  60 #define PTRACE_O_TRACEEXIT      0x00000040
  61
  62 /* Wait extended result codes for the above trace options.  */
  63 #define PTRACE_EVENT_FORK       1
  64 #define PTRACE_EVENT_VFORK      2
  65 #define PTRACE_EVENT_CLONE      3
  66 #define PTRACE_EVENT_EXEC       4
  67 #define PTRACE_EVENT_VFORK_DONE 5
  68 #define PTRACE_EVENT_EXIT       6
  69
  70 #endif /* PTRACE_EVENT_FORK */
  71
  72 #ifndef PTRACE_O_EXITKILL
  73 /* Only defined in Linux Kernel 3.8 or later.  */
  74 #define PTRACE_O_EXITKILL       0x00100000
  75 #endif
  76
  77 #if (defined __bfin__ || defined __frv__ || defined __sh__) \
  78     && !defined PTRACE_GETFDPIC
  79 #define PTRACE_GETFDPIC         31
  80 #define PTRACE_GETFDPIC_EXEC    0
  81 #define PTRACE_GETFDPIC_INTERP  1
  82 #endif
  83
  84 /* We can't always assume that this flag is available, but all systems
  85    with the ptrace event handlers also have __WALL, so it's safe to use
  86    in some contexts.  */
  87 #ifndef __WALL
  88 #define __WALL          0x40000000 /* Wait for any child.  */
  89 #endif
  90
  91 /* True if whether a breakpoint/watchpoint triggered can be determined
  92    from the si_code of SIGTRAP's siginfo_t (TRAP_BRKPT/TRAP_HWBKPT).
  93    That is, if the kernel can tell us whether the thread executed a
  94    software breakpoint, we trust it.  The kernel will be determining
  95    that from the hardware (e.g., from which exception was raised in
  96    the CPU).  Relying on whether a breakpoint is planted in memory at
  97    the time the SIGTRAP is processed to determine whether the thread
  98    stopped for a software breakpoint can be too late.  E.g., the
  99    breakpoint could have been removed since.  Or the thread could have
 100    stepped an instruction the size of a breakpoint instruction, and
 101    before the stop is processed a breakpoint is inserted at its
 102    address.  Getting these wrong is disastrous on decr_pc_after_break
 103    architectures.  The moribund location mechanism helps with that
 104    somewhat but it is an heuristic, and can well fail.  Getting that
 105    information out of the kernel and ultimately out of the CPU is the
 106    way to go.  That said, some architecture may get the si_code wrong,
 107    and as such we're leaving fallback code in place.  We'll remove
 108    this after a while if no problem is reported.  */
 109 #define USE_SIGTRAP_SIGINFO 1
 110
 111 /* The x86 kernel gets some of the si_code values backwards, like
 112    this:
 113
 114    | what                                     | si_code    |
 115    |------------------------------------------+------------|
 116    | software breakpoints (int3)              | SI_KERNEL  |
 117    | single-steps                             | TRAP_TRACE |
 118    | single-stepping a syscall                | TRAP_BRKPT |
 119    | user sent SIGTRAP                        | 0          |
 120    | exec SIGTRAP (when no PTRACE_EVENT_EXEC) | 0          |
 121    | hardware breakpoints/watchpoints         | TRAP_HWBPT |
 122
 123    That is, it reports SI_KERNEL for software breakpoints (and only
 124    for those), and TRAP_BRKPT for single-stepping a syscall...  If the
 125    kernel is ever fixed, we'll just have to detect it like we detect
 126    optional ptrace features: by forking and debugging ourselves,
 127    running to a breakpoint and checking what comes out of
 128    siginfo->si_code.
 129
 130    The generic Linux target code should use GDB_ARCH_TRAP_BRKPT
 131    instead of TRAP_BRKPT to abstract out this x86 peculiarity.  */
 132 #if defined __i386__ || defined __x86_64__
 133 # define GDB_ARCH_TRAP_BRKPT SI_KERNEL
 134 #else
 135 # define GDB_ARCH_TRAP_BRKPT TRAP_BRKPT
 136 #endif
 137
 138 #ifndef TRAP_HWBKPT
 139 # define TRAP_HWBKPT 4
 140 #endif
 141
 142 extern void linux_ptrace_attach_fail_reason (pid_t pid, struct buffer *buffer);
 143
 144 /* Find all possible reasons we could have failed to attach to PTID
 145    and return them as a string.  ERR is the error PTRACE_ATTACH failed
 146    with (an errno).  The result is stored in a static buffer.  This
 147    string should be copied into a buffer by the client if the string
 148    will not be immediately used, or if it must persist.  */
 149 extern char *linux_ptrace_attach_fail_reason_string (ptid_t ptid, int err);
 150
 151 extern void linux_ptrace_init_warnings (void);
 152 extern void linux_check_ptrace_features (void);
 153 extern void linux_enable_event_reporting (pid_t pid, int attached);
 154 extern void linux_disable_event_reporting (pid_t pid);
 155 extern int linux_supports_tracefork (void);
 156 extern int linux_supports_traceclone (void);
 157 extern int linux_supports_tracevforkdone (void);
 158 extern int linux_supports_tracesysgood (void);
 159 extern void linux_ptrace_set_additional_flags (int);
 160 extern int linux_ptrace_get_extended_event (int wstat);
 161 extern int linux_is_extended_waitstatus (int wstat);
 162 extern int linux_wstatus_maybe_breakpoint (int wstat);
 163
 164 #endif /* COMMON_LINUX_PTRACE_H */