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_OPENBSD || 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_openbsd.h" 23 #include "sanitizer_platform_limits_posix.h" 24 #include "sanitizer_platform_limits_solaris.h" 25 #include "sanitizer_posix.h" 26 27 struct link_map; // Opaque type returned by dlopen(). 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 uptr internal_clock_gettime(__sanitizer_clockid_t clk_id, void *tp); 53 54 // Linux-only syscalls. 55 #if SANITIZER_LINUX 56 uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5); 57 // Used only by sanitizer_stoptheworld. Signal handlers that are actually used 58 // (like the process-wide error reporting SEGV handler) must use 59 // internal_sigaction instead. 60 int internal_sigaction_norestorer(int signum, const void *act, void *oldact); 61 void internal_sigdelset(__sanitizer_sigset_t *set, int signum); 62 #if defined(__x86_64__) || defined(__mips__) || defined(__aarch64__) \ 63 || defined(__powerpc64__) || defined(__s390__) || defined(__i386__) \ 64 || defined(__arm__) 65 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg, 66 int *parent_tidptr, void *newtls, int *child_tidptr); 67 #endif 68 #elif SANITIZER_FREEBSD 69 void internal_sigdelset(__sanitizer_sigset_t *set, int signum); 70 #elif SANITIZER_NETBSD 71 void internal_sigdelset(__sanitizer_sigset_t *set, int signum); 72 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg); 73 #endif // SANITIZER_LINUX 74 75 // This class reads thread IDs from /proc/<pid>/task using only syscalls. 76 class ThreadLister { 77 public: 78 explicit ThreadLister(pid_t pid); 79 ~ThreadLister(); 80 enum Result { 81 Error, 82 Incomplete, 83 Ok, 84 }; 85 Result ListThreads(InternalMmapVector<tid_t> *threads); 86 87 private: 88 bool IsAlive(int tid); 89 90 pid_t pid_; 91 int descriptor_ = -1; 92 InternalMmapVector<char> buffer_; 93 }; 94 95 // Exposed for testing. 96 uptr ThreadDescriptorSize(); 97 uptr ThreadSelf(); 98 uptr ThreadSelfOffset(); 99 100 // Matches a library's file name against a base name (stripping path and version 101 // information). 102 bool LibraryNameIs(const char *full_name, const char *base_name); 103 104 // Call cb for each region mapped by map. 105 void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr)); 106 107 // Releases memory pages entirely within the [beg, end] address range. 108 // The pages no longer count toward RSS; reads are guaranteed to return 0. 109 // Requires (but does not verify!) that pages are MAP_PRIVATE. 110 INLINE void ReleaseMemoryPagesToOSAndZeroFill(uptr beg, uptr end) { 111 // man madvise on Linux promises zero-fill for anonymous private pages. 112 // Testing shows the same behaviour for private (but not anonymous) mappings 113 // of shm_open() files, as long as the underlying file is untouched. 114 CHECK(SANITIZER_LINUX); 115 ReleaseMemoryPagesToOS(beg, end); 116 } 117 118 #if SANITIZER_ANDROID 119 120 #if defined(__aarch64__) 121 # define __get_tls() \ 122 ({ void** __v; __asm__("mrs %0, tpidr_el0" : "=r"(__v)); __v; }) 123 #elif defined(__arm__) 124 # define __get_tls() \ 125 ({ void** __v; __asm__("mrc p15, 0, %0, c13, c0, 3" : "=r"(__v)); __v; }) 126 #elif defined(__mips__) 127 // On mips32r1, this goes via a kernel illegal instruction trap that's 128 // optimized for v1. 129 # define __get_tls() \ 130 ({ register void** __v asm("v1"); \ 131 __asm__(".set push\n" \ 132 ".set mips32r2\n" \ 133 "rdhwr %0,$29\n" \ 134 ".set pop\n" : "=r"(__v)); \ 135 __v; }) 136 #elif defined(__i386__) 137 # define __get_tls() \ 138 ({ void** __v; __asm__("movl %%gs:0, %0" : "=r"(__v)); __v; }) 139 #elif defined(__x86_64__) 140 # define __get_tls() \ 141 ({ void** __v; __asm__("mov %%fs:0, %0" : "=r"(__v)); __v; }) 142 #else 143 #error "Unsupported architecture." 144 #endif 145 146 // The Android Bionic team has allocated a TLS slot for sanitizers starting 147 // with Q, given that Android currently doesn't support ELF TLS. It is used to 148 // store sanitizer thread specific data. 149 static const int TLS_SLOT_SANITIZER = 6; 150 151 ALWAYS_INLINE uptr *get_android_tls_ptr() { 152 return reinterpret_cast<uptr *>(&__get_tls()[TLS_SLOT_SANITIZER]); 153 } 154 155 #endif // SANITIZER_ANDROID 156 157 } // namespace __sanitizer 158 159 #endif 160 #endif // SANITIZER_LINUX_H 161