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
26 struct link_map; // Opaque type returned by dlopen().
27 struct utsname;
28
29 namespace __sanitizer {
30 // Dirent structure for getdents(). Note that this structure is different from
31 // the one in <dirent.h>, which is used by readdir().
32 struct linux_dirent;
33
34 struct ProcSelfMapsBuff {
35 char *data;
36 uptr mmaped_size;
37 uptr len;
38 };
39
40 struct MemoryMappingLayoutData {
41 ProcSelfMapsBuff proc_self_maps;
42 const char *current;
43 };
44
45 void ReadProcMaps(ProcSelfMapsBuff *proc_maps);
46
47 // Syscall wrappers.
48 uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count);
49 uptr internal_sigaltstack(const void *ss, void *oss);
50 uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set,
51 __sanitizer_sigset_t *oldset);
52
53 void SetSigProcMask(__sanitizer_sigset_t *set, __sanitizer_sigset_t *oldset);
54 void BlockSignals(__sanitizer_sigset_t *oldset = nullptr);
55 struct ScopedBlockSignals {
56 explicit ScopedBlockSignals(__sanitizer_sigset_t *copy);
57 ~ScopedBlockSignals();
58
59 ScopedBlockSignals &operator=(const ScopedBlockSignals &) = delete;
60 ScopedBlockSignals(const ScopedBlockSignals &) = delete;
61
62 private:
63 __sanitizer_sigset_t saved_;
64 };
65
66 # if SANITIZER_GLIBC
67 uptr internal_clock_gettime(__sanitizer_clockid_t clk_id, void *tp);
68 # endif
69
70 // Linux-only syscalls.
71 # if SANITIZER_LINUX
72 uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5);
73 # if defined(__x86_64__)
74 uptr internal_arch_prctl(int option, uptr arg2);
75 # endif
76 // Used only by sanitizer_stoptheworld. Signal handlers that are actually used
77 // (like the process-wide error reporting SEGV handler) must use
78 // internal_sigaction instead.
79 int internal_sigaction_norestorer(int signum, const void *act, void *oldact);
80 void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
81 # if defined(__x86_64__) || defined(__mips__) || defined(__aarch64__) || \
82 defined(__powerpc64__) || defined(__s390__) || defined(__i386__) || \
83 defined(__arm__) || SANITIZER_RISCV64 || SANITIZER_LOONGARCH64
84 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
85 int *parent_tidptr, void *newtls, int *child_tidptr);
86 # endif
87 int internal_uname(struct utsname *buf);
88 # elif SANITIZER_FREEBSD
89 uptr internal_procctl(int type, int id, int cmd, void *data);
90 void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
91 # elif SANITIZER_NETBSD
92 void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
93 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg);
94 # endif // SANITIZER_LINUX
95
96 // This class reads thread IDs from /proc/<pid>/task using only syscalls.
97 class ThreadLister {
98 public:
99 explicit ThreadLister(pid_t pid);
100 ~ThreadLister();
101 enum Result {
102 Error,
103 Incomplete,
104 Ok,
105 };
106 Result ListThreads(InternalMmapVector<tid_t> *threads);
107
108 private:
109 bool IsAlive(int tid);
110
111 pid_t pid_;
112 int descriptor_ = -1;
113 InternalMmapVector<char> buffer_;
114 };
115
116 // Exposed for testing.
117 uptr ThreadDescriptorSize();
118 uptr ThreadSelf();
119
120 // Matches a library's file name against a base name (stripping path and version
121 // information).
122 bool LibraryNameIs(const char *full_name, const char *base_name);
123
124 // Call cb for each region mapped by map.
125 void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr));
126
127 // Releases memory pages entirely within the [beg, end] address range.
128 // The pages no longer count toward RSS; reads are guaranteed to return 0.
129 // Requires (but does not verify!) that pages are MAP_PRIVATE.
ReleaseMemoryPagesToOSAndZeroFill(uptr beg,uptr end)130 inline void ReleaseMemoryPagesToOSAndZeroFill(uptr beg, uptr end) {
131 // man madvise on Linux promises zero-fill for anonymous private pages.
132 // Testing shows the same behaviour for private (but not anonymous) mappings
133 // of shm_open() files, as long as the underlying file is untouched.
134 CHECK(SANITIZER_LINUX);
135 ReleaseMemoryPagesToOS(beg, end);
136 }
137
138 # if SANITIZER_ANDROID
139
140 # if defined(__aarch64__)
141 # define __get_tls() \
142 ({ \
143 void **__v; \
144 __asm__("mrs %0, tpidr_el0" : "=r"(__v)); \
145 __v; \
146 })
147 # elif defined(__arm__)
148 # define __get_tls() \
149 ({ \
150 void **__v; \
151 __asm__("mrc p15, 0, %0, c13, c0, 3" : "=r"(__v)); \
152 __v; \
153 })
154 # elif defined(__mips__)
155 // On mips32r1, this goes via a kernel illegal instruction trap that's
156 // optimized for v1.
157 # define __get_tls() \
158 ({ \
159 register void **__v asm("v1"); \
160 __asm__( \
161 ".set push\n" \
162 ".set mips32r2\n" \
163 "rdhwr %0,$29\n" \
164 ".set pop\n" \
165 : "=r"(__v)); \
166 __v; \
167 })
168 # elif defined(__riscv)
169 # define __get_tls() \
170 ({ \
171 void **__v; \
172 __asm__("mv %0, tp" : "=r"(__v)); \
173 __v; \
174 })
175 # elif defined(__i386__)
176 # define __get_tls() \
177 ({ \
178 void **__v; \
179 __asm__("movl %%gs:0, %0" : "=r"(__v)); \
180 __v; \
181 })
182 # elif defined(__x86_64__)
183 # define __get_tls() \
184 ({ \
185 void **__v; \
186 __asm__("mov %%fs:0, %0" : "=r"(__v)); \
187 __v; \
188 })
189 # else
190 # error "Unsupported architecture."
191 # endif
192
193 // The Android Bionic team has allocated a TLS slot for sanitizers starting
194 // with Q, given that Android currently doesn't support ELF TLS. It is used to
195 // store sanitizer thread specific data.
196 static const int TLS_SLOT_SANITIZER = 6;
197
get_android_tls_ptr()198 ALWAYS_INLINE uptr *get_android_tls_ptr() {
199 return reinterpret_cast<uptr *>(&__get_tls()[TLS_SLOT_SANITIZER]);
200 }
201
202 # endif // SANITIZER_ANDROID
203
204 } // namespace __sanitizer
205
206 #endif
207 #endif // SANITIZER_LINUX_H
208