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 || SANITIZER_HAIKU
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
34# if SANITIZER_HAIKU
35struct MemoryMappingLayoutData {
36 long signed int cookie;
37};
38# else
39struct ProcSelfMapsBuff {
40 char *data;
41 uptr mmaped_size;
42 uptr len;
43};
44
45struct MemoryMappingLayoutData {
46 ProcSelfMapsBuff proc_self_maps;
47 const char *current;
48};
49
50void ReadProcMaps(ProcSelfMapsBuff *proc_maps);
51# endif // SANITIZER_HAIKU
52
53// Syscall wrappers.
54uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count);
55uptr internal_sigaltstack(const void *ss, void *oss);
56uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set,
57 __sanitizer_sigset_t *oldset);
58
59void SetSigProcMask(__sanitizer_sigset_t *set, __sanitizer_sigset_t *oldset);
60void BlockSignals(__sanitizer_sigset_t *oldset = nullptr);
61struct ScopedBlockSignals {
62 explicit ScopedBlockSignals(__sanitizer_sigset_t *copy);
63 ~ScopedBlockSignals();
64
65 ScopedBlockSignals &operator=(const ScopedBlockSignals &) = delete;
66 ScopedBlockSignals(const ScopedBlockSignals &) = delete;
67
68 private:
69 __sanitizer_sigset_t saved_;
70};
71
72# if SANITIZER_GLIBC
73uptr internal_clock_gettime(__sanitizer_clockid_t clk_id, void *tp);
74# endif
75
76// Linux-only syscalls.
77# if SANITIZER_LINUX
78uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5);
79# if defined(__x86_64__)
80uptr internal_arch_prctl(int option, uptr arg2);
81# endif
82// Used only by sanitizer_stoptheworld. Signal handlers that are actually used
83// (like the process-wide error reporting SEGV handler) must use
84// internal_sigaction instead.
85int internal_sigaction_norestorer(int signum, const void *act, void *oldact);
86void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
87# if defined(__x86_64__) || defined(__mips__) || defined(__aarch64__) || \
88 defined(__powerpc64__) || defined(__s390__) || defined(__i386__) || \
89 defined(__arm__) || defined(__hexagon__) || SANITIZER_RISCV64 || \
90 SANITIZER_LOONGARCH64
91uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
92 int *parent_tidptr, void *newtls, int *child_tidptr);
93# endif
94int internal_uname(struct utsname *buf);
95# elif SANITIZER_FREEBSD
96uptr internal_procctl(int type, int id, int cmd, void *data);
97void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
98# elif SANITIZER_NETBSD
99void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
100uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg);
101# endif // SANITIZER_LINUX
102
103// This class reads thread IDs from /proc/<pid>/task using only syscalls.
104class ThreadLister {
105 public:
106 explicit ThreadLister(pid_t pid);
107 enum Result {
108 Error,
109 Incomplete,
110 Ok,
111 };
112 Result ListThreads(InternalMmapVector<ThreadID> *threads);
113 const char *LoadStatus(ThreadID tid);
114
115 private:
116 bool IsAlive(ThreadID tid);
117
118 InternalScopedString task_path_;
119 InternalScopedString status_path_;
120 InternalMmapVector<char> buffer_;
121};
122
123// Exposed for testing.
124uptr ThreadDescriptorSize();
125uptr ThreadSelf();
126
127// Matches a library's file name against a base name (stripping path and version
128// information).
129bool LibraryNameIs(const char *full_name, const char *base_name);
130
131// Call cb for each region mapped by map.
132void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr));
133
134// Releases memory pages entirely within the [beg, end) address range.
135// The pages no longer count toward RSS; reads are guaranteed to return 0.
136// Requires (but does not verify!) that pages are MAP_PRIVATE.
137inline void ReleaseMemoryPagesToOSAndZeroFill(uptr beg, uptr end) {
138 // man madvise on Linux promises zero-fill for anonymous private pages.
139 // Testing shows the same behaviour for private (but not anonymous) mappings
140 // of shm_open() files, as long as the underlying file is untouched.
141 CHECK(SANITIZER_LINUX);
142 ReleaseMemoryPagesToOS(beg, end);
143}
144
145# if SANITIZER_ANDROID
146
147# if defined(__aarch64__)
148# define __get_tls() \
149 ({ \
150 void **__v; \
151 __asm__("mrs %0, tpidr_el0" : "=r"(__v)); \
152 __v; \
153 })
154# elif defined(__arm__)
155# define __get_tls() \
156 ({ \
157 void **__v; \
158 __asm__("mrc p15, 0, %0, c13, c0, 3" : "=r"(__v)); \
159 __v; \
160 })
161# elif defined(__mips__)
162// On mips32r1, this goes via a kernel illegal instruction trap that's
163// optimized for v1.
164# define __get_tls() \
165 ({ \
166 register void **__v asm("v1"); \
167 __asm__( \
168 ".set push\n" \
169 ".set mips32r2\n" \
170 "rdhwr %0,$29\n" \
171 ".set pop\n" \
172 : "=r"(__v)); \
173 __v; \
174 })
175# elif defined(__riscv)
176# define __get_tls() \
177 ({ \
178 void **__v; \
179 __asm__("mv %0, tp" : "=r"(__v)); \
180 __v; \
181 })
182# elif defined(__i386__)
183# define __get_tls() \
184 ({ \
185 void **__v; \
186 __asm__("movl %%gs:0, %0" : "=r"(__v)); \
187 __v; \
188 })
189# elif defined(__x86_64__)
190# define __get_tls() \
191 ({ \
192 void **__v; \
193 __asm__("mov %%fs:0, %0" : "=r"(__v)); \
194 __v; \
195 })
196# else
197# error "Unsupported architecture."
198# endif
199
200// The Android Bionic team has allocated a TLS slot for sanitizers starting
201// with Q, given that Android currently doesn't support ELF TLS. It is used to
202// store sanitizer thread specific data.
203static const int TLS_SLOT_SANITIZER = 6;
204
205ALWAYS_INLINE uptr *get_android_tls_ptr() {
206 return reinterpret_cast<uptr *>(&__get_tls()[TLS_SLOT_SANITIZER]);
207}
208
209# endif // SANITIZER_ANDROID
210
211} // namespace __sanitizer
212
213#endif
214#endif // SANITIZER_LINUX_H
215