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_posix.h"
23#include "sanitizer_platform_limits_solaris.h"
24#include "sanitizer_posix.h"
25
26struct link_map;  // Opaque type returned by dlopen().
27struct utsname;
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);
52
53void SetSigProcMask(__sanitizer_sigset_t *set, __sanitizer_sigset_t *oldset);
54struct ScopedBlockSignals {
55  explicit ScopedBlockSignals(__sanitizer_sigset_t *copy);
56  ~ScopedBlockSignals();
57
58  ScopedBlockSignals &operator=(const ScopedBlockSignals &) = delete;
59  ScopedBlockSignals(const ScopedBlockSignals &) = delete;
60
61 private:
62  __sanitizer_sigset_t saved_;
63};
64
65#  if SANITIZER_GLIBC
66uptr internal_clock_gettime(__sanitizer_clockid_t clk_id, void *tp);
67#endif
68
69// Linux-only syscalls.
70#if SANITIZER_LINUX
71uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5);
72#    if defined(__x86_64__)
73uptr internal_arch_prctl(int option, uptr arg2);
74#    endif
75// Used only by sanitizer_stoptheworld. Signal handlers that are actually used
76// (like the process-wide error reporting SEGV handler) must use
77// internal_sigaction instead.
78int internal_sigaction_norestorer(int signum, const void *act, void *oldact);
79void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
80#    if defined(__x86_64__) || defined(__mips__) || defined(__aarch64__) || \
81        defined(__powerpc64__) || defined(__s390__) || defined(__i386__) || \
82        defined(__arm__) || SANITIZER_RISCV64 || SANITIZER_LOONGARCH64
83uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
84                    int *parent_tidptr, void *newtls, int *child_tidptr);
85#endif
86int internal_uname(struct utsname *buf);
87#elif SANITIZER_FREEBSD
88uptr internal_procctl(int type, int id, int cmd, void *data);
89void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
90#elif SANITIZER_NETBSD
91void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
92uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg);
93#endif  // SANITIZER_LINUX
94
95// This class reads thread IDs from /proc/<pid>/task using only syscalls.
96class ThreadLister {
97 public:
98  explicit ThreadLister(pid_t pid);
99  ~ThreadLister();
100  enum Result {
101    Error,
102    Incomplete,
103    Ok,
104  };
105  Result ListThreads(InternalMmapVector<tid_t> *threads);
106
107 private:
108  bool IsAlive(int tid);
109
110  pid_t pid_;
111  int descriptor_ = -1;
112  InternalMmapVector<char> buffer_;
113};
114
115// Exposed for testing.
116uptr ThreadDescriptorSize();
117uptr ThreadSelf();
118
119// Matches a library's file name against a base name (stripping path and version
120// information).
121bool LibraryNameIs(const char *full_name, const char *base_name);
122
123// Call cb for each region mapped by map.
124void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr));
125
126// Releases memory pages entirely within the [beg, end] address range.
127// The pages no longer count toward RSS; reads are guaranteed to return 0.
128// Requires (but does not verify!) that pages are MAP_PRIVATE.
129inline void ReleaseMemoryPagesToOSAndZeroFill(uptr beg, uptr end) {
130  // man madvise on Linux promises zero-fill for anonymous private pages.
131  // Testing shows the same behaviour for private (but not anonymous) mappings
132  // of shm_open() files, as long as the underlying file is untouched.
133  CHECK(SANITIZER_LINUX);
134  ReleaseMemoryPagesToOS(beg, end);
135}
136
137#if SANITIZER_ANDROID
138
139#if defined(__aarch64__)
140# define __get_tls() \
141    ({ void** __v; __asm__("mrs %0, tpidr_el0" : "=r"(__v)); __v; })
142#elif defined(__arm__)
143# define __get_tls() \
144    ({ void** __v; __asm__("mrc p15, 0, %0, c13, c0, 3" : "=r"(__v)); __v; })
145#elif defined(__mips__)
146// On mips32r1, this goes via a kernel illegal instruction trap that's
147// optimized for v1.
148# define __get_tls() \
149    ({ register void** __v asm("v1"); \
150       __asm__(".set    push\n" \
151               ".set    mips32r2\n" \
152               "rdhwr   %0,$29\n" \
153               ".set    pop\n" : "=r"(__v)); \
154       __v; })
155#elif defined(__i386__)
156# define __get_tls() \
157    ({ void** __v; __asm__("movl %%gs:0, %0" : "=r"(__v)); __v; })
158#elif defined(__x86_64__)
159# define __get_tls() \
160    ({ void** __v; __asm__("mov %%fs:0, %0" : "=r"(__v)); __v; })
161#else
162#error "Unsupported architecture."
163#endif
164
165// The Android Bionic team has allocated a TLS slot for sanitizers starting
166// with Q, given that Android currently doesn't support ELF TLS. It is used to
167// store sanitizer thread specific data.
168static const int TLS_SLOT_SANITIZER = 6;
169
170ALWAYS_INLINE uptr *get_android_tls_ptr() {
171  return reinterpret_cast<uptr *>(&__get_tls()[TLS_SLOT_SANITIZER]);
172}
173
174#endif  // SANITIZER_ANDROID
175
176}  // namespace __sanitizer
177
178#endif
179#endif  // SANITIZER_LINUX_H
180