1//===-- sanitizer_linux.h ---------------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// Linux-specific syscall wrappers and classes.
10//
11//===----------------------------------------------------------------------===//
12#ifndef SANITIZER_LINUX_H
13#define SANITIZER_LINUX_H
14
15#include "sanitizer_platform.h"
16#if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD ||                \
17    SANITIZER_OPENBSD || SANITIZER_SOLARIS
18#include "sanitizer_common.h"
19#include "sanitizer_internal_defs.h"
20#include "sanitizer_platform_limits_freebsd.h"
21#include "sanitizer_platform_limits_netbsd.h"
22#include "sanitizer_platform_limits_openbsd.h"
23#include "sanitizer_platform_limits_posix.h"
24#include "sanitizer_platform_limits_solaris.h"
25#include "sanitizer_posix.h"
26
27struct link_map;  // Opaque type returned by dlopen().
28
29namespace __sanitizer {
30// Dirent structure for getdents(). Note that this structure is different from
31// the one in <dirent.h>, which is used by readdir().
32struct linux_dirent;
33
34struct ProcSelfMapsBuff {
35  char *data;
36  uptr mmaped_size;
37  uptr len;
38};
39
40struct MemoryMappingLayoutData {
41  ProcSelfMapsBuff proc_self_maps;
42  const char *current;
43};
44
45void ReadProcMaps(ProcSelfMapsBuff *proc_maps);
46
47// Syscall wrappers.
48uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count);
49uptr internal_sigaltstack(const void* ss, void* oss);
50uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set,
51    __sanitizer_sigset_t *oldset);
52uptr internal_clock_gettime(__sanitizer_clockid_t clk_id, void *tp);
53
54// Linux-only syscalls.
55#if SANITIZER_LINUX
56uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5);
57// Used only by sanitizer_stoptheworld. Signal handlers that are actually used
58// (like the process-wide error reporting SEGV handler) must use
59// internal_sigaction instead.
60int internal_sigaction_norestorer(int signum, const void *act, void *oldact);
61void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
62#if defined(__x86_64__) || defined(__mips__) || defined(__aarch64__) \
63  || defined(__powerpc64__) || defined(__s390__) || defined(__i386__) \
64  || defined(__arm__)
65uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
66                    int *parent_tidptr, void *newtls, int *child_tidptr);
67#endif
68#elif SANITIZER_FREEBSD
69void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
70#elif SANITIZER_NETBSD
71void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
72uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg);
73#endif  // SANITIZER_LINUX
74
75// This class reads thread IDs from /proc/<pid>/task using only syscalls.
76class ThreadLister {
77 public:
78  explicit ThreadLister(pid_t pid);
79  ~ThreadLister();
80  enum Result {
81    Error,
82    Incomplete,
83    Ok,
84  };
85  Result ListThreads(InternalMmapVector<tid_t> *threads);
86
87 private:
88  bool IsAlive(int tid);
89
90  pid_t pid_;
91  int descriptor_ = -1;
92  InternalMmapVector<char> buffer_;
93};
94
95// Exposed for testing.
96uptr ThreadDescriptorSize();
97uptr ThreadSelf();
98uptr ThreadSelfOffset();
99
100// Matches a library's file name against a base name (stripping path and version
101// information).
102bool LibraryNameIs(const char *full_name, const char *base_name);
103
104// Call cb for each region mapped by map.
105void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr));
106
107// Releases memory pages entirely within the [beg, end] address range.
108// The pages no longer count toward RSS; reads are guaranteed to return 0.
109// Requires (but does not verify!) that pages are MAP_PRIVATE.
110INLINE void ReleaseMemoryPagesToOSAndZeroFill(uptr beg, uptr end) {
111  // man madvise on Linux promises zero-fill for anonymous private pages.
112  // Testing shows the same behaviour for private (but not anonymous) mappings
113  // of shm_open() files, as long as the underlying file is untouched.
114  CHECK(SANITIZER_LINUX);
115  ReleaseMemoryPagesToOS(beg, end);
116}
117
118#if SANITIZER_ANDROID
119
120#if defined(__aarch64__)
121# define __get_tls() \
122    ({ void** __v; __asm__("mrs %0, tpidr_el0" : "=r"(__v)); __v; })
123#elif defined(__arm__)
124# define __get_tls() \
125    ({ void** __v; __asm__("mrc p15, 0, %0, c13, c0, 3" : "=r"(__v)); __v; })
126#elif defined(__mips__)
127// On mips32r1, this goes via a kernel illegal instruction trap that's
128// optimized for v1.
129# define __get_tls() \
130    ({ register void** __v asm("v1"); \
131       __asm__(".set    push\n" \
132               ".set    mips32r2\n" \
133               "rdhwr   %0,$29\n" \
134               ".set    pop\n" : "=r"(__v)); \
135       __v; })
136#elif defined(__i386__)
137# define __get_tls() \
138    ({ void** __v; __asm__("movl %%gs:0, %0" : "=r"(__v)); __v; })
139#elif defined(__x86_64__)
140# define __get_tls() \
141    ({ void** __v; __asm__("mov %%fs:0, %0" : "=r"(__v)); __v; })
142#else
143#error "Unsupported architecture."
144#endif
145
146// The Android Bionic team has allocated a TLS slot for sanitizers starting
147// with Q, given that Android currently doesn't support ELF TLS. It is used to
148// store sanitizer thread specific data.
149static const int TLS_SLOT_SANITIZER = 6;
150
151ALWAYS_INLINE uptr *get_android_tls_ptr() {
152  return reinterpret_cast<uptr *>(&__get_tls()[TLS_SLOT_SANITIZER]);
153}
154
155#endif  // SANITIZER_ANDROID
156
157}  // namespace __sanitizer
158
159#endif
160#endif  // SANITIZER_LINUX_H
161