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
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 # if SANITIZER_HAIKU
35 struct MemoryMappingLayoutData {
36 long signed int cookie;
37 };
38 # else
39 struct ProcSelfMapsBuff {
40 char *data;
41 uptr mmaped_size;
42 uptr len;
43 };
44
45 struct MemoryMappingLayoutData {
46 ProcSelfMapsBuff proc_self_maps;
47 const char *current;
48 };
49
50 void ReadProcMaps(ProcSelfMapsBuff *proc_maps);
51 # endif // SANITIZER_HAIKU
52
53 // Syscall wrappers.
54 uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count);
55 uptr internal_sigaltstack(const void *ss, void *oss);
56 uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set,
57 __sanitizer_sigset_t *oldset);
58
59 void SetSigProcMask(__sanitizer_sigset_t *set, __sanitizer_sigset_t *oldset);
60 void BlockSignals(__sanitizer_sigset_t *oldset = nullptr);
61 struct 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
73 uptr internal_clock_gettime(__sanitizer_clockid_t clk_id, void *tp);
74 # endif
75
76 // Linux-only syscalls.
77 # if SANITIZER_LINUX
78 uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5);
79 # if defined(__x86_64__)
80 uptr 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.
85 int internal_sigaction_norestorer(int signum, const void *act, void *oldact);
86 void 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
90 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
91 int *parent_tidptr, void *newtls, int *child_tidptr);
92 # endif
93 int internal_uname(struct utsname *buf);
94 # elif SANITIZER_FREEBSD
95 uptr internal_procctl(int type, int id, int cmd, void *data);
96 void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
97 # elif SANITIZER_NETBSD
98 void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
99 uptr 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.
103 class 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.
123 uptr ThreadDescriptorSize();
124 uptr ThreadSelf();
125
126 // Matches a library's file name against a base name (stripping path and version
127 // information).
128 bool LibraryNameIs(const char *full_name, const char *base_name);
129
130 // Call cb for each region mapped by map.
131 void 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.
ReleaseMemoryPagesToOSAndZeroFill(uptr beg,uptr end)136 inline 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.
202 static const int TLS_SLOT_SANITIZER = 6;
203
get_android_tls_ptr()204 ALWAYS_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
214