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_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#if SANITIZER_GLIBC
53uptr internal_clock_gettime(__sanitizer_clockid_t clk_id, void *tp);
54#endif
55
56// Linux-only syscalls.
57#if SANITIZER_LINUX
58uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5);
59// Used only by sanitizer_stoptheworld. Signal handlers that are actually used
60// (like the process-wide error reporting SEGV handler) must use
61// internal_sigaction instead.
62int internal_sigaction_norestorer(int signum, const void *act, void *oldact);
63void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
64#if defined(__x86_64__) || defined(__mips__) || defined(__aarch64__) || \
65 defined(__powerpc64__) || defined(__s390__) || defined(__i386__) || \
66 defined(__arm__) || SANITIZER_RISCV64
67uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
68 int *parent_tidptr, void *newtls, int *child_tidptr);
69#endif
70int internal_uname(struct utsname *buf);
71#elif SANITIZER_FREEBSD
72void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
73#elif SANITIZER_NETBSD
74void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
75uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg);
76#endif // SANITIZER_LINUX
77
78// This class reads thread IDs from /proc/<pid>/task using only syscalls.
79class ThreadLister {
80 public:
81 explicit ThreadLister(pid_t pid);
82 ~ThreadLister();
83 enum Result {
84 Error,
85 Incomplete,
86 Ok,
87 };
88 Result ListThreads(InternalMmapVector<tid_t> *threads);
89
90 private:
91 bool IsAlive(int tid);
92
93 pid_t pid_;
94 int descriptor_ = -1;
95 InternalMmapVector<char> buffer_;
96};
97
98// Exposed for testing.
99uptr ThreadDescriptorSize();
100uptr ThreadSelf();
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