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linux-ptrace.h
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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 #ifndef PTRACE_GETREGSET
47 #define PTRACE_GETREGSET 0x4204
48 #endif
49 
50 #ifndef PTRACE_SETREGSET
51 #define PTRACE_SETREGSET 0x4205
52 #endif
53 
54 /* If the system headers did not provide the constants, hard-code the normal
55  values. */
56 #ifndef PTRACE_EVENT_FORK
57 
58 #define PTRACE_SETOPTIONS 0x4200
59 #define PTRACE_GETEVENTMSG 0x4201
60 
61 /* options set using PTRACE_SETOPTIONS */
62 #define PTRACE_O_TRACESYSGOOD 0x00000001
63 #define PTRACE_O_TRACEFORK 0x00000002
64 #define PTRACE_O_TRACEVFORK 0x00000004
65 #define PTRACE_O_TRACECLONE 0x00000008
66 #define PTRACE_O_TRACEEXEC 0x00000010
67 #define PTRACE_O_TRACEVFORKDONE 0x00000020
68 #define PTRACE_O_TRACEEXIT 0x00000040
69 
70 /* Wait extended result codes for the above trace options. */
71 #define PTRACE_EVENT_FORK 1
72 #define PTRACE_EVENT_VFORK 2
73 #define PTRACE_EVENT_CLONE 3
74 #define PTRACE_EVENT_EXEC 4
75 #define PTRACE_EVENT_VFORK_DONE 5
76 #define PTRACE_EVENT_EXIT 6
77 
78 #endif /* PTRACE_EVENT_FORK */
79 
80 #ifndef PTRACE_O_EXITKILL
81 /* Only defined in Linux Kernel 3.8 or later. */
82 #define PTRACE_O_EXITKILL 0x00100000
83 #endif
84 
85 #if (defined __bfin__ || defined __frv__ || defined __sh__) \
86  && !defined PTRACE_GETFDPIC
87 #define PTRACE_GETFDPIC 31
88 #define PTRACE_GETFDPIC_EXEC 0
89 #define PTRACE_GETFDPIC_INTERP 1
90 #endif
91 
92 /* We can't always assume that this flag is available, but all systems
93  with the ptrace event handlers also have __WALL, so it's safe to use
94  in some contexts. */
95 #ifndef __WALL
96 #define __WALL 0x40000000 /* Wait for any child. */
97 #endif
98 
99 /* True if whether a breakpoint/watchpoint triggered can be determined
100  from the si_code of SIGTRAP's siginfo_t (TRAP_BRKPT/TRAP_HWBKPT).
101  That is, if the kernel can tell us whether the thread executed a
102  software breakpoint, we trust it. The kernel will be determining
103  that from the hardware (e.g., from which exception was raised in
104  the CPU). Relying on whether a breakpoint is planted in memory at
105  the time the SIGTRAP is processed to determine whether the thread
106  stopped for a software breakpoint can be too late. E.g., the
107  breakpoint could have been removed since. Or the thread could have
108  stepped an instruction the size of a breakpoint instruction, and
109  before the stop is processed a breakpoint is inserted at its
110  address. Getting these wrong is disastrous on decr_pc_after_break
111  architectures. The moribund location mechanism helps with that
112  somewhat but it is an heuristic, and can well fail. Getting that
113  information out of the kernel and ultimately out of the CPU is the
114  way to go. That said, some architecture may get the si_code wrong,
115  and as such we're leaving fallback code in place. We'll remove
116  this after a while if no problem is reported. */
117 #define USE_SIGTRAP_SIGINFO 1
118 
119 /* The x86 kernel gets some of the si_code values backwards, like
120  this:
121 
122  | what | si_code |
123  |------------------------------------------+------------|
124  | software breakpoints (int3) | SI_KERNEL |
125  | single-steps | TRAP_TRACE |
126  | single-stepping a syscall | TRAP_BRKPT |
127  | user sent SIGTRAP | 0 |
128  | exec SIGTRAP (when no PTRACE_EVENT_EXEC) | 0 |
129  | hardware breakpoints/watchpoints | TRAP_HWBPT |
130 
131  That is, it reports SI_KERNEL for software breakpoints (and only
132  for those), and TRAP_BRKPT for single-stepping a syscall... If the
133  kernel is ever fixed, we'll just have to detect it like we detect
134  optional ptrace features: by forking and debugging ourselves,
135  running to a breakpoint and checking what comes out of
136  siginfo->si_code.
137 
138  The generic Linux target code should use GDB_ARCH_TRAP_BRKPT
139  instead of TRAP_BRKPT to abstract out this x86 peculiarity. */
140 #if defined __i386__ || defined __x86_64__
141 # define GDB_ARCH_TRAP_BRKPT SI_KERNEL
142 #else
143 # define GDB_ARCH_TRAP_BRKPT TRAP_BRKPT
144 #endif
145 
146 #ifndef TRAP_HWBKPT
147 # define TRAP_HWBKPT 4
148 #endif
149 
150 extern void linux_ptrace_attach_fail_reason (pid_t pid, struct buffer *buffer);
151 
152 /* Find all possible reasons we could have failed to attach to PTID
153  and return them as a string. ERR is the error PTRACE_ATTACH failed
154  with (an errno). The result is stored in a static buffer. This
155  string should be copied into a buffer by the client if the string
156  will not be immediately used, or if it must persist. */
158 
159 extern void linux_ptrace_init_warnings (void);
160 extern void linux_check_ptrace_features (void);
161 extern void linux_enable_event_reporting (pid_t pid, int attached);
162 extern void linux_disable_event_reporting (pid_t pid);
163 extern int linux_supports_tracefork (void);
164 extern int linux_supports_traceclone (void);
165 extern int linux_supports_tracevforkdone (void);
166 extern int linux_supports_tracesysgood (void);
167 extern int linux_ptrace_get_extended_event (int wstat);
168 extern int linux_is_extended_waitstatus (int wstat);
169 extern int linux_wstatus_maybe_breakpoint (int wstat);
170 
171 #endif /* COMMON_LINUX_PTRACE_H */
void linux_ptrace_init_warnings(void)
Definition: linux-ptrace.c:573
void linux_enable_event_reporting(pid_t pid, int attached)
Definition: linux-ptrace.c:489
int linux_supports_tracefork(void)
Definition: linux-ptrace.c:535
Definition: ptid.h:35
int linux_ptrace_get_extended_event(int wstat)
Definition: linux-ptrace.c:587
int linux_is_extended_waitstatus(int wstat)
Definition: linux-ptrace.c:595
mach_port_t mach_port_t name mach_port_t mach_port_t name error_t err
Definition: gnu-nat.c:1816
void linux_disable_event_reporting(pid_t pid)
Definition: linux-ptrace.c:510
char * linux_ptrace_attach_fail_reason_string(ptid_t ptid, int err)
Definition: linux-ptrace.c:55
void linux_ptrace_attach_fail_reason(pid_t pid, struct buffer *buffer)
Definition: linux-ptrace.c:36
void linux_check_ptrace_features(void)
Definition: linux-ptrace.c:335
Definition: buffer.h:23
int linux_supports_tracevforkdone(void)
Definition: linux-ptrace.c:555
int linux_supports_tracesysgood(void)
Definition: linux-ptrace.c:564
int linux_wstatus_maybe_breakpoint(int wstat)
Definition: linux-ptrace.c:603
mach_port_t mach_port_t name mach_port_t mach_port_t name error_t int int rusage_t pid_t pid
Definition: gnu-nat.c:1818
int linux_supports_traceclone(void)
Definition: linux-ptrace.c:546