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