1 //===-- sanitizer_linux_libcdep.cc ----------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file is shared between AddressSanitizer and ThreadSanitizer 11 // run-time libraries and implements linux-specific functions from 12 // sanitizer_libc.h. 13 //===----------------------------------------------------------------------===// 14 15 #include "sanitizer_platform.h" 16 #if SANITIZER_LINUX 17 18 #include "sanitizer_common.h" 19 #include "sanitizer_procmaps.h" 20 #include "sanitizer_stacktrace.h" 21 22 #include <dlfcn.h> 23 #include <pthread.h> 24 #include <sys/prctl.h> 25 #include <sys/resource.h> 26 #include <unwind.h> 27 28 namespace __sanitizer { 29 30 void GetThreadStackTopAndBottom(bool at_initialization, uptr *stack_top, 31 uptr *stack_bottom) { 32 static const uptr kMaxThreadStackSize = 1 << 30; // 1Gb 33 CHECK(stack_top); 34 CHECK(stack_bottom); 35 if (at_initialization) { 36 // This is the main thread. Libpthread may not be initialized yet. 37 struct rlimit rl; 38 CHECK_EQ(getrlimit(RLIMIT_STACK, &rl), 0); 39 40 // Find the mapping that contains a stack variable. 41 MemoryMappingLayout proc_maps(/*cache_enabled*/true); 42 uptr start, end, offset; 43 uptr prev_end = 0; 44 while (proc_maps.Next(&start, &end, &offset, 0, 0, /* protection */0)) { 45 if ((uptr)&rl < end) 46 break; 47 prev_end = end; 48 } 49 CHECK((uptr)&rl >= start && (uptr)&rl < end); 50 51 // Get stacksize from rlimit, but clip it so that it does not overlap 52 // with other mappings. 53 uptr stacksize = rl.rlim_cur; 54 if (stacksize > end - prev_end) 55 stacksize = end - prev_end; 56 // When running with unlimited stack size, we still want to set some limit. 57 // The unlimited stack size is caused by 'ulimit -s unlimited'. 58 // Also, for some reason, GNU make spawns subprocesses with unlimited stack. 59 if (stacksize > kMaxThreadStackSize) 60 stacksize = kMaxThreadStackSize; 61 *stack_top = end; 62 *stack_bottom = end - stacksize; 63 return; 64 } 65 pthread_attr_t attr; 66 pthread_attr_init(&attr); 67 CHECK_EQ(pthread_getattr_np(pthread_self(), &attr), 0); 68 uptr stacksize = 0; 69 void *stackaddr = 0; 70 pthread_attr_getstack(&attr, &stackaddr, (size_t*)&stacksize); 71 pthread_attr_destroy(&attr); 72 73 CHECK_LE(stacksize, kMaxThreadStackSize); // Sanity check. 74 *stack_top = (uptr)stackaddr + stacksize; 75 *stack_bottom = (uptr)stackaddr; 76 } 77 78 // Does not compile for Go because dlsym() requires -ldl 79 #ifndef SANITIZER_GO 80 bool SetEnv(const char *name, const char *value) { 81 void *f = dlsym(RTLD_NEXT, "setenv"); 82 if (f == 0) 83 return false; 84 typedef int(*setenv_ft)(const char *name, const char *value, int overwrite); 85 setenv_ft setenv_f; 86 CHECK_EQ(sizeof(setenv_f), sizeof(f)); 87 internal_memcpy(&setenv_f, &f, sizeof(f)); 88 return setenv_f(name, value, 1) == 0; 89 } 90 #endif 91 92 bool SanitizerSetThreadName(const char *name) { 93 #ifdef PR_SET_NAME 94 return 0 == prctl(PR_SET_NAME, (unsigned long)name, 0, 0, 0); // NOLINT 95 #else 96 return false; 97 #endif 98 } 99 100 bool SanitizerGetThreadName(char *name, int max_len) { 101 #ifdef PR_GET_NAME 102 char buff[17]; 103 if (prctl(PR_GET_NAME, (unsigned long)buff, 0, 0, 0)) // NOLINT 104 return false; 105 internal_strncpy(name, buff, max_len); 106 name[max_len] = 0; 107 return true; 108 #else 109 return false; 110 #endif 111 } 112 113 #ifndef SANITIZER_GO 114 //------------------------- SlowUnwindStack ----------------------------------- 115 #ifdef __arm__ 116 #define UNWIND_STOP _URC_END_OF_STACK 117 #define UNWIND_CONTINUE _URC_NO_REASON 118 #else 119 #define UNWIND_STOP _URC_NORMAL_STOP 120 #define UNWIND_CONTINUE _URC_NO_REASON 121 #endif 122 123 uptr Unwind_GetIP(struct _Unwind_Context *ctx) { 124 #ifdef __arm__ 125 uptr val; 126 _Unwind_VRS_Result res = _Unwind_VRS_Get(ctx, _UVRSC_CORE, 127 15 /* r15 = PC */, _UVRSD_UINT32, &val); 128 CHECK(res == _UVRSR_OK && "_Unwind_VRS_Get failed"); 129 // Clear the Thumb bit. 130 return val & ~(uptr)1; 131 #else 132 return _Unwind_GetIP(ctx); 133 #endif 134 } 135 136 _Unwind_Reason_Code Unwind_Trace(struct _Unwind_Context *ctx, void *param) { 137 StackTrace *b = (StackTrace*)param; 138 CHECK(b->size < b->max_size); 139 uptr pc = Unwind_GetIP(ctx); 140 b->trace[b->size++] = pc; 141 if (b->size == b->max_size) return UNWIND_STOP; 142 return UNWIND_CONTINUE; 143 } 144 145 static bool MatchPc(uptr cur_pc, uptr trace_pc) { 146 return cur_pc - trace_pc <= 64 || trace_pc - cur_pc <= 64; 147 } 148 149 void StackTrace::SlowUnwindStack(uptr pc, uptr max_depth) { 150 this->size = 0; 151 this->max_size = max_depth; 152 if (max_depth > 1) { 153 _Unwind_Backtrace(Unwind_Trace, this); 154 // We need to pop a few frames so that pc is on top. 155 // trace[0] belongs to the current function so we always pop it. 156 int to_pop = 1; 157 /**/ if (size > 1 && MatchPc(pc, trace[1])) to_pop = 1; 158 else if (size > 2 && MatchPc(pc, trace[2])) to_pop = 2; 159 else if (size > 3 && MatchPc(pc, trace[3])) to_pop = 3; 160 else if (size > 4 && MatchPc(pc, trace[4])) to_pop = 4; 161 else if (size > 5 && MatchPc(pc, trace[5])) to_pop = 5; 162 this->PopStackFrames(to_pop); 163 } 164 this->trace[0] = pc; 165 } 166 167 #endif // !SANITIZER_GO 168 169 static uptr g_tls_size; 170 171 #ifdef __i386__ 172 # define DL_INTERNAL_FUNCTION __attribute__((regparm(3), stdcall)) 173 #else 174 # define DL_INTERNAL_FUNCTION 175 #endif 176 177 void InitTlsSize() { 178 #if !defined(SANITIZER_GO) && !SANITIZER_ANDROID 179 typedef void (*get_tls_func)(size_t*, size_t*) DL_INTERNAL_FUNCTION; 180 get_tls_func get_tls; 181 void *get_tls_static_info_ptr = dlsym(RTLD_NEXT, "_dl_get_tls_static_info"); 182 CHECK_EQ(sizeof(get_tls), sizeof(get_tls_static_info_ptr)); 183 internal_memcpy(&get_tls, &get_tls_static_info_ptr, 184 sizeof(get_tls_static_info_ptr)); 185 CHECK_NE(get_tls, 0); 186 size_t tls_size = 0; 187 size_t tls_align = 0; 188 get_tls(&tls_size, &tls_align); 189 g_tls_size = tls_size; 190 #endif 191 } 192 193 uptr GetTlsSize() { 194 return g_tls_size; 195 } 196 197 #if defined(__x86_64__) || defined(__i386__) 198 // sizeof(struct thread) from glibc. 199 // There has been a report of this being different on glibc 2.11. We don't know 200 // when this change happened, so 2.12 is a conservative estimate. 201 #if __GLIBC_PREREQ(2, 12) 202 const uptr kThreadDescriptorSize = FIRST_32_SECOND_64(1216, 2304); 203 #else 204 const uptr kThreadDescriptorSize = FIRST_32_SECOND_64(1168, 2304); 205 #endif 206 207 uptr ThreadDescriptorSize() { 208 return kThreadDescriptorSize; 209 } 210 211 // The offset at which pointer to self is located in the thread descriptor. 212 const uptr kThreadSelfOffset = FIRST_32_SECOND_64(8, 16); 213 214 uptr ThreadSelfOffset() { 215 return kThreadSelfOffset; 216 } 217 218 uptr ThreadSelf() { 219 uptr descr_addr; 220 #ifdef __i386__ 221 asm("mov %%gs:%c1,%0" : "=r"(descr_addr) : "i"(kThreadSelfOffset)); 222 #else 223 asm("mov %%fs:%c1,%0" : "=r"(descr_addr) : "i"(kThreadSelfOffset)); 224 #endif 225 return descr_addr; 226 } 227 #endif // defined(__x86_64__) || defined(__i386__) 228 229 void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size, 230 uptr *tls_addr, uptr *tls_size) { 231 #ifndef SANITIZER_GO 232 #if defined(__x86_64__) || defined(__i386__) 233 *tls_addr = ThreadSelf(); 234 *tls_size = GetTlsSize(); 235 *tls_addr -= *tls_size; 236 *tls_addr += kThreadDescriptorSize; 237 #else 238 *tls_addr = 0; 239 *tls_size = 0; 240 #endif 241 242 uptr stack_top, stack_bottom; 243 GetThreadStackTopAndBottom(main, &stack_top, &stack_bottom); 244 *stk_addr = stack_bottom; 245 *stk_size = stack_top - stack_bottom; 246 247 if (!main) { 248 // If stack and tls intersect, make them non-intersecting. 249 if (*tls_addr > *stk_addr && *tls_addr < *stk_addr + *stk_size) { 250 CHECK_GT(*tls_addr + *tls_size, *stk_addr); 251 CHECK_LE(*tls_addr + *tls_size, *stk_addr + *stk_size); 252 *stk_size -= *tls_size; 253 *tls_addr = *stk_addr + *stk_size; 254 } 255 } 256 #else // SANITIZER_GO 257 *stk_addr = 0; 258 *stk_size = 0; 259 *tls_addr = 0; 260 *tls_size = 0; 261 #endif // SANITIZER_GO 262 } 263 264 void AdjustStackSizeLinux(void *attr_, int verbosity) { 265 pthread_attr_t *attr = (pthread_attr_t *)attr_; 266 uptr stackaddr = 0; 267 size_t stacksize = 0; 268 pthread_attr_getstack(attr, (void**)&stackaddr, &stacksize); 269 // GLibC will return (0 - stacksize) as the stack address in the case when 270 // stacksize is set, but stackaddr is not. 271 bool stack_set = (stackaddr != 0) && (stackaddr + stacksize != 0); 272 // We place a lot of tool data into TLS, account for that. 273 const uptr minstacksize = GetTlsSize() + 128*1024; 274 if (stacksize < minstacksize) { 275 if (!stack_set) { 276 if (verbosity && stacksize != 0) 277 Printf("Sanitizer: increasing stacksize %zu->%zu\n", stacksize, 278 minstacksize); 279 pthread_attr_setstacksize(attr, minstacksize); 280 } else { 281 Printf("Sanitizer: pre-allocated stack size is insufficient: " 282 "%zu < %zu\n", stacksize, minstacksize); 283 Printf("Sanitizer: pthread_create is likely to fail.\n"); 284 } 285 } 286 } 287 288 } // namespace __sanitizer 289 290 #endif // SANITIZER_LINUX 291
