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