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 180