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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__) || SANITIZER_RISCV64 || SANITIZER_LOONGARCH64
90uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
91 int *parent_tidptr, void *newtls, int *child_tidptr);
92# endif
93int internal_uname(struct utsname *buf);
94# elif SANITIZER_FREEBSD
95uptr internal_procctl(int type, int id, int cmd, void *data);
96void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
97# elif SANITIZER_NETBSD
98void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
99uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg);
100# endif // SANITIZER_LINUX
101
102// This class reads thread IDs from /proc/<pid>/task using only syscalls.
103class ThreadLister {
104 public:
105 explicit ThreadLister(pid_t pid);
106 enum Result {
107 Error,
108 Incomplete,
109 Ok,
110 };
111 Result ListThreads(InternalMmapVector<tid_t> *threads);
112 const char *LoadStatus(tid_t tid);
113
114 private:
115 bool IsAlive(tid_t tid);
116
117 InternalScopedString task_path_;
118 InternalScopedString status_path_;
119 InternalMmapVector<char> buffer_;
120};
121
122// Exposed for testing.
123uptr ThreadDescriptorSize();
124uptr ThreadSelf();
125
126// Matches a library's file name against a base name (stripping path and version
127// information).
128bool LibraryNameIs(const char *full_name, const char *base_name);
129
130// Call cb for each region mapped by map.
131void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr));
132
133// Releases memory pages entirely within the [beg, end) address range.
134// The pages no longer count toward RSS; reads are guaranteed to return 0.
135// Requires (but does not verify!) that pages are MAP_PRIVATE.
136inline void ReleaseMemoryPagesToOSAndZeroFill(uptr beg, uptr end) {
137 // man madvise on Linux promises zero-fill for anonymous private pages.
138 // Testing shows the same behaviour for private (but not anonymous) mappings
139 // of shm_open() files, as long as the underlying file is untouched.
140 CHECK(SANITIZER_LINUX);
141 ReleaseMemoryPagesToOS(beg, end);
142}
143
144# if SANITIZER_ANDROID
145
146# if defined(__aarch64__)
147# define __get_tls() \
148 ({ \
149 void **__v; \
150 __asm__("mrs %0, tpidr_el0" : "=r"(__v)); \
151 __v; \
152 })
153# elif defined(__arm__)
154# define __get_tls() \
155 ({ \
156 void **__v; \
157 __asm__("mrc p15, 0, %0, c13, c0, 3" : "=r"(__v)); \
158 __v; \
159 })
160# elif defined(__mips__)
161// On mips32r1, this goes via a kernel illegal instruction trap that's
162// optimized for v1.
163# define __get_tls() \
164 ({ \
165 register void **__v asm("v1"); \
166 __asm__( \
167 ".set push\n" \
168 ".set mips32r2\n" \
169 "rdhwr %0,$29\n" \
170 ".set pop\n" \
171 : "=r"(__v)); \
172 __v; \
173 })
174# elif defined(__riscv)
175# define __get_tls() \
176 ({ \
177 void **__v; \
178 __asm__("mv %0, tp" : "=r"(__v)); \
179 __v; \
180 })
181# elif defined(__i386__)
182# define __get_tls() \
183 ({ \
184 void **__v; \
185 __asm__("movl %%gs:0, %0" : "=r"(__v)); \
186 __v; \
187 })
188# elif defined(__x86_64__)
189# define __get_tls() \
190 ({ \
191 void **__v; \
192 __asm__("mov %%fs:0, %0" : "=r"(__v)); \
193 __v; \
194 })
195# else
196# error "Unsupported architecture."
197# endif
198
199// The Android Bionic team has allocated a TLS slot for sanitizers starting
200// with Q, given that Android currently doesn't support ELF TLS. It is used to
201// store sanitizer thread specific data.
202static const int TLS_SLOT_SANITIZER = 6;
203
204ALWAYS_INLINE uptr *get_android_tls_ptr() {
205 return reinterpret_cast<uptr *>(&__get_tls()[TLS_SLOT_SANITIZER]);
206}
207
208# endif // SANITIZER_ANDROID
209
210} // namespace __sanitizer
211
212#endif
213#endif // SANITIZER_LINUX_H