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. 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; 197 198 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