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().
28struct utsname;
29
30namespace __sanitizer {
31// Dirent structure for getdents(). Note that this structure is different from
32// the one in <dirent.h>, which is used by readdir().
33struct linux_dirent;
34
35struct ProcSelfMapsBuff {
36  char *data;
37  uptr mmaped_size;
38  uptr len;
39};
40
41struct MemoryMappingLayoutData {
42  ProcSelfMapsBuff proc_self_maps;
43  const char *current;
44};
45
46void ReadProcMaps(ProcSelfMapsBuff *proc_maps);
47
48// Syscall wrappers.
49uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count);
50uptr internal_sigaltstack(const void* ss, void* oss);
51uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set,
52    __sanitizer_sigset_t *oldset);
53uptr internal_clock_gettime(__sanitizer_clockid_t clk_id, void *tp);
54
55// Linux-only syscalls.
56#if SANITIZER_LINUX
57uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5);
58// Used only by sanitizer_stoptheworld. Signal handlers that are actually used
59// (like the process-wide error reporting SEGV handler) must use
60// internal_sigaction instead.
61int internal_sigaction_norestorer(int signum, const void *act, void *oldact);
62void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
63#if defined(__x86_64__) || defined(__mips__) || defined(__aarch64__) \
64  || defined(__powerpc64__) || defined(__s390__) || defined(__i386__) \
65  || defined(__arm__)
66uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
67                    int *parent_tidptr, void *newtls, int *child_tidptr);
68#endif
69int internal_uname(struct utsname *buf);
70#elif SANITIZER_FREEBSD
71void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
72#elif SANITIZER_NETBSD
73void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
74uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg);
75#endif  // SANITIZER_LINUX
76
77// This class reads thread IDs from /proc/<pid>/task using only syscalls.
78class ThreadLister {
79 public:
80  explicit ThreadLister(pid_t pid);
81  ~ThreadLister();
82  enum Result {
83    Error,
84    Incomplete,
85    Ok,
86  };
87  Result ListThreads(InternalMmapVector<tid_t> *threads);
88
89 private:
90  bool IsAlive(int tid);
91
92  pid_t pid_;
93  int descriptor_ = -1;
94  InternalMmapVector<char> buffer_;
95};
96
97// Exposed for testing.
98uptr ThreadDescriptorSize();
99uptr ThreadSelf();
100uptr ThreadSelfOffset();
101
102// Matches a library's file name against a base name (stripping path and version
103// information).
104bool LibraryNameIs(const char *full_name, const char *base_name);
105
106// Call cb for each region mapped by map.
107void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr));
108
109// Releases memory pages entirely within the [beg, end] address range.
110// The pages no longer count toward RSS; reads are guaranteed to return 0.
111// Requires (but does not verify!) that pages are MAP_PRIVATE.
112INLINE void ReleaseMemoryPagesToOSAndZeroFill(uptr beg, uptr end) {
113  // man madvise on Linux promises zero-fill for anonymous private pages.
114  // Testing shows the same behaviour for private (but not anonymous) mappings
115  // of shm_open() files, as long as the underlying file is untouched.
116  CHECK(SANITIZER_LINUX);
117  ReleaseMemoryPagesToOS(beg, end);
118}
119
120#if SANITIZER_ANDROID
121
122#if defined(__aarch64__)
123# define __get_tls() \
124    ({ void** __v; __asm__("mrs %0, tpidr_el0" : "=r"(__v)); __v; })
125#elif defined(__arm__)
126# define __get_tls() \
127    ({ void** __v; __asm__("mrc p15, 0, %0, c13, c0, 3" : "=r"(__v)); __v; })
128#elif defined(__mips__)
129// On mips32r1, this goes via a kernel illegal instruction trap that's
130// optimized for v1.
131# define __get_tls() \
132    ({ register void** __v asm("v1"); \
133       __asm__(".set    push\n" \
134               ".set    mips32r2\n" \
135               "rdhwr   %0,$29\n" \
136               ".set    pop\n" : "=r"(__v)); \
137       __v; })
138#elif defined(__i386__)
139# define __get_tls() \
140    ({ void** __v; __asm__("movl %%gs:0, %0" : "=r"(__v)); __v; })
141#elif defined(__x86_64__)
142# define __get_tls() \
143    ({ void** __v; __asm__("mov %%fs:0, %0" : "=r"(__v)); __v; })
144#else
145#error "Unsupported architecture."
146#endif
147
148// The Android Bionic team has allocated a TLS slot for sanitizers starting
149// with Q, given that Android currently doesn't support ELF TLS. It is used to
150// store sanitizer thread specific data.
151static const int TLS_SLOT_SANITIZER = 6;
152
153ALWAYS_INLINE uptr *get_android_tls_ptr() {
154  return reinterpret_cast<uptr *>(&__get_tls()[TLS_SLOT_SANITIZER]);
155}
156
157#endif  // SANITIZER_ANDROID
158
159}  // namespace __sanitizer
160
161#endif
162#endif  // SANITIZER_LINUX_H
163