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