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 struct utsname; 29 30 namespace __sanitizer { 31 // Dirent structure for getdents(). Note that this structure is different from 32 // the one in <dirent.h>, which is used by readdir(). 33 struct linux_dirent; 34 35 struct ProcSelfMapsBuff { 36 char *data; 37 uptr mmaped_size; 38 uptr len; 39 }; 40 41 struct MemoryMappingLayoutData { 42 ProcSelfMapsBuff proc_self_maps; 43 const char *current; 44 }; 45 46 void ReadProcMaps(ProcSelfMapsBuff *proc_maps); 47 48 // Syscall wrappers. 49 uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count); 50 uptr internal_sigaltstack(const void* ss, void* oss); 51 uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set, 52 __sanitizer_sigset_t *oldset); 53 uptr internal_clock_gettime(__sanitizer_clockid_t clk_id, void *tp); 54 55 // Linux-only syscalls. 56 #if SANITIZER_LINUX 57 uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5); 58 // Used only by sanitizer_stoptheworld. Signal handlers that are actually used 59 // (like the process-wide error reporting SEGV handler) must use 60 // internal_sigaction instead. 61 int internal_sigaction_norestorer(int signum, const void *act, void *oldact); 62 void internal_sigdelset(__sanitizer_sigset_t *set, int signum); 63 #if defined(__x86_64__) || defined(__mips__) || defined(__aarch64__) \ 64 || defined(__powerpc64__) || defined(__s390__) || defined(__i386__) \ 65 || defined(__arm__) 66 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg, 67 int *parent_tidptr, void *newtls, int *child_tidptr); 68 #endif 69 int internal_uname(struct utsname *buf); 70 #elif SANITIZER_FREEBSD 71 void internal_sigdelset(__sanitizer_sigset_t *set, int signum); 72 #elif SANITIZER_NETBSD 73 void internal_sigdelset(__sanitizer_sigset_t *set, int signum); 74 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg); 75 #endif // SANITIZER_LINUX 76 77 // This class reads thread IDs from /proc/<pid>/task using only syscalls. 78 class ThreadLister { 79 public: 80 explicit ThreadLister(pid_t pid); 81 ~ThreadLister(); 82 enum Result { 83 Error, 84 Incomplete, 85 Ok, 86 }; 87 Result ListThreads(InternalMmapVector<tid_t> *threads); 88 89 private: 90 bool IsAlive(int tid); 91 92 pid_t pid_; 93 int descriptor_ = -1; 94 InternalMmapVector<char> buffer_; 95 }; 96 97 // Exposed for testing. 98 uptr ThreadDescriptorSize(); 99 uptr ThreadSelf(); 100 uptr ThreadSelfOffset(); 101 102 // Matches a library's file name against a base name (stripping path and version 103 // information). 104 bool LibraryNameIs(const char *full_name, const char *base_name); 105 106 // Call cb for each region mapped by map. 107 void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr)); 108 109 // Releases memory pages entirely within the [beg, end] address range. 110 // The pages no longer count toward RSS; reads are guaranteed to return 0. 111 // Requires (but does not verify!) that pages are MAP_PRIVATE. 112 INLINE void ReleaseMemoryPagesToOSAndZeroFill(uptr beg, uptr end) { 113 // man madvise on Linux promises zero-fill for anonymous private pages. 114 // Testing shows the same behaviour for private (but not anonymous) mappings 115 // of shm_open() files, as long as the underlying file is untouched. 116 CHECK(SANITIZER_LINUX); 117 ReleaseMemoryPagesToOS(beg, end); 118 } 119 120 #if SANITIZER_ANDROID 121 122 #if defined(__aarch64__) 123 # define __get_tls() \ 124 ({ void** __v; __asm__("mrs %0, tpidr_el0" : "=r"(__v)); __v; }) 125 #elif defined(__arm__) 126 # define __get_tls() \ 127 ({ void** __v; __asm__("mrc p15, 0, %0, c13, c0, 3" : "=r"(__v)); __v; }) 128 #elif defined(__mips__) 129 // On mips32r1, this goes via a kernel illegal instruction trap that's 130 // optimized for v1. 131 # define __get_tls() \ 132 ({ register void** __v asm("v1"); \ 133 __asm__(".set push\n" \ 134 ".set mips32r2\n" \ 135 "rdhwr %0,$29\n" \ 136 ".set pop\n" : "=r"(__v)); \ 137 __v; }) 138 #elif defined(__i386__) 139 # define __get_tls() \ 140 ({ void** __v; __asm__("movl %%gs:0, %0" : "=r"(__v)); __v; }) 141 #elif defined(__x86_64__) 142 # define __get_tls() \ 143 ({ void** __v; __asm__("mov %%fs:0, %0" : "=r"(__v)); __v; }) 144 #else 145 #error "Unsupported architecture." 146 #endif 147 148 // The Android Bionic team has allocated a TLS slot for sanitizers starting 149 // with Q, given that Android currently doesn't support ELF TLS. It is used to 150 // store sanitizer thread specific data. 151 static const int TLS_SLOT_SANITIZER = 6; 152 153 ALWAYS_INLINE uptr *get_android_tls_ptr() { 154 return reinterpret_cast<uptr *>(&__get_tls()[TLS_SLOT_SANITIZER]); 155 } 156 157 #endif // SANITIZER_ANDROID 158 159 } // namespace __sanitizer 160 161 #endif 162 #endif // SANITIZER_LINUX_H 163