libsanitizer/tsan/tsan_platform_linux.cc

   1 //===-- tsan_platform_linux.cc --------------------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is a part of ThreadSanitizer (TSan), a race detector.
   9 //
  10 // Linux-specific code.
  11 //===----------------------------------------------------------------------===//
  12
  13
  14 #include "sanitizer_common/sanitizer_platform.h"
  15 #if SANITIZER_LINUX
  16
  17 #include "sanitizer_common/sanitizer_common.h"
  18 #include "sanitizer_common/sanitizer_libc.h"
  19 #include "sanitizer_common/sanitizer_procmaps.h"
  20 #include "sanitizer_common/sanitizer_stoptheworld.h"
  21 #include "tsan_platform.h"
  22 #include "tsan_rtl.h"
  23 #include "tsan_flags.h"
  24
  25 #include <fcntl.h>
  26 #include <pthread.h>
  27 #include <signal.h>
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <stdarg.h>
  32 #include <sys/mman.h>
  33 #include <sys/prctl.h>
  34 #include <sys/syscall.h>
  35 #include <sys/socket.h>
  36 #include <sys/time.h>
  37 #include <sys/types.h>
  38 #include <sys/resource.h>
  39 #include <sys/stat.h>
  40 #include <unistd.h>
  41 #include <errno.h>
  42 #include <sched.h>
  43 #include <dlfcn.h>
  44 #define __need_res_state
  45 #include <resolv.h>
  46 #include <malloc.h>
  47
  48 #ifdef sa_handler
  49 # undef sa_handler
  50 #endif
  51
  52 #ifdef sa_sigaction
  53 # undef sa_sigaction
  54 #endif
  55
  56 extern "C" struct mallinfo __libc_mallinfo();
  57
  58 namespace __tsan {
  59
  60 const uptr kPageSize = 4096;
  61
  62 #ifndef TSAN_GO
  63 ScopedInRtl::ScopedInRtl()
  64     : thr_(cur_thread()) {
  65   in_rtl_ = thr_->in_rtl;
  66   thr_->in_rtl++;
  67   errno_ = errno;
  68 }
  69
  70 ScopedInRtl::~ScopedInRtl() {
  71   thr_->in_rtl--;
  72   errno = errno_;
  73   CHECK_EQ(in_rtl_, thr_->in_rtl);
  74 }
  75 #else
  76 ScopedInRtl::ScopedInRtl() {
  77 }
  78
  79 ScopedInRtl::~ScopedInRtl() {
  80 }
  81 #endif
  82
  83 void FillProfileCallback(uptr start, uptr rss, bool file,
  84                          uptr *mem, uptr stats_size) {
  85   CHECK_EQ(7, stats_size);
  86   mem[6] += rss;  // total
  87   start >>= 40;
  88   if (start < 0x10)  // shadow
  89     mem[0] += rss;
  90   else if (start >= 0x20 && start < 0x30)  // compat modules
  91     mem[file ? 1 : 2] += rss;
  92   else if (start >= 0x7e)  // modules
  93     mem[file ? 1 : 2] += rss;
  94   else if (start >= 0x60 && start < 0x62)  // traces
  95     mem[3] += rss;
  96   else if (start >= 0x7d && start < 0x7e)  // heap
  97     mem[4] += rss;
  98   else  // other
  99     mem[5] += rss;
 100 }
 101
 102 void WriteMemoryProfile(char *buf, uptr buf_size) {
 103   uptr mem[7] = {};
 104   __sanitizer::GetMemoryProfile(FillProfileCallback, mem, 7);
 105   char *buf_pos = buf;
 106   char *buf_end = buf + buf_size;
 107   buf_pos += internal_snprintf(buf_pos, buf_end - buf_pos,
 108       "RSS %zd MB: shadow:%zd file:%zd mmap:%zd trace:%zd heap:%zd other:%zd\n",
 109       mem[6] >> 20, mem[0] >> 20, mem[1] >> 20, mem[2] >> 20,
 110       mem[3] >> 20, mem[4] >> 20, mem[5] >> 20);
 111   struct mallinfo mi = __libc_mallinfo();
 112   buf_pos += internal_snprintf(buf_pos, buf_end - buf_pos,
 113       "mallinfo: arena=%d mmap=%d fordblks=%d keepcost=%d\n",
 114       mi.arena >> 20, mi.hblkhd >> 20, mi.fordblks >> 20, mi.keepcost >> 20);
 115 }
 116
 117 uptr GetRSS() {
 118   uptr mem[7] = {};
 119   __sanitizer::GetMemoryProfile(FillProfileCallback, mem, 7);
 120   return mem[6];
 121 }
 122
 123
 124 void FlushShadowMemoryCallback(
 125     const SuspendedThreadsList &suspended_threads_list,
 126     void *argument) {
 127   FlushUnneededShadowMemory(kLinuxShadowBeg, kLinuxShadowEnd - kLinuxShadowBeg);
 128 }
 129
 130 void FlushShadowMemory() {
 131   StopTheWorld(FlushShadowMemoryCallback, 0);
 132 }
 133
 134 #ifndef TSAN_GO
 135 static void ProtectRange(uptr beg, uptr end) {
 136   ScopedInRtl in_rtl;
 137   CHECK_LE(beg, end);
 138   if (beg == end)
 139     return;
 140   if (beg != (uptr)Mprotect(beg, end - beg)) {
 141     Printf("FATAL: ThreadSanitizer can not protect [%zx,%zx]\n", beg, end);
 142     Printf("FATAL: Make sure you are not using unlimited stack\n");
 143     Die();
 144   }
 145 }
 146 #endif
 147
 148 #ifndef TSAN_GO
 149 // Mark shadow for .rodata sections with the special kShadowRodata marker.
 150 // Accesses to .rodata can't race, so this saves time, memory and trace space.
 151 static void MapRodata() {
 152   // First create temp file.
 153   const char *tmpdir = GetEnv("TMPDIR");
 154   if (tmpdir == 0)
 155     tmpdir = GetEnv("TEST_TMPDIR");
 156 #ifdef P_tmpdir
 157   if (tmpdir == 0)
 158     tmpdir = P_tmpdir;
 159 #endif
 160   if (tmpdir == 0)
 161     return;
 162   char filename[256];
 163   internal_snprintf(filename, sizeof(filename), "%s/tsan.rodata.%d",
 164                     tmpdir, (int)internal_getpid());
 165   uptr openrv = internal_open(filename, O_RDWR | O_CREAT | O_EXCL, 0600);
 166   if (internal_iserror(openrv))
 167     return;
 168   fd_t fd = openrv;
 169   // Fill the file with kShadowRodata.
 170   const uptr kMarkerSize = 512 * 1024 / sizeof(u64);
 171   InternalScopedBuffer<u64> marker(kMarkerSize);
 172   for (u64 *p = marker.data(); p < marker.data() + kMarkerSize; p++)
 173     *p = kShadowRodata;
 174   internal_write(fd, marker.data(), marker.size());
 175   // Map the file into memory.
 176   uptr page = internal_mmap(0, kPageSize, PROT_READ | PROT_WRITE,
 177                             MAP_PRIVATE | MAP_ANONYMOUS, fd, 0);
 178   if (internal_iserror(page)) {
 179     internal_close(fd);
 180     internal_unlink(filename);
 181     return;
 182   }
 183   // Map the file into shadow of .rodata sections.
 184   MemoryMappingLayout proc_maps(/*cache_enabled*/true);
 185   uptr start, end, offset, prot;
 186   char name[128];
 187   while (proc_maps.Next(&start, &end, &offset, name, ARRAY_SIZE(name), &prot)) {
 188     if (name[0] != 0 && name[0] != '['
 189         && (prot & MemoryMappingLayout::kProtectionRead)
 190         && (prot & MemoryMappingLayout::kProtectionExecute)
 191         && !(prot & MemoryMappingLayout::kProtectionWrite)
 192         && IsAppMem(start)) {
 193       // Assume it's .rodata
 194       char *shadow_start = (char*)MemToShadow(start);
 195       char *shadow_end = (char*)MemToShadow(end);
 196       for (char *p = shadow_start; p < shadow_end; p += marker.size()) {
 197         internal_mmap(p, Min<uptr>(marker.size(), shadow_end - p),
 198                       PROT_READ, MAP_PRIVATE | MAP_FIXED, fd, 0);
 199       }
 200     }
 201   }
 202   internal_close(fd);
 203   internal_unlink(filename);
 204 }
 205
 206 void InitializeShadowMemory() {
 207   uptr shadow = (uptr)MmapFixedNoReserve(kLinuxShadowBeg,
 208     kLinuxShadowEnd - kLinuxShadowBeg);
 209   if (shadow != kLinuxShadowBeg) {
 210     Printf("FATAL: ThreadSanitizer can not mmap the shadow memory\n");
 211     Printf("FATAL: Make sure to compile with -fPIE and "
 212                "to link with -pie (%p, %p).\n", shadow, kLinuxShadowBeg);
 213     Die();
 214   }
 215   const uptr kClosedLowBeg  = 0x200000;
 216   const uptr kClosedLowEnd  = kLinuxShadowBeg - 1;
 217   const uptr kClosedMidBeg = kLinuxShadowEnd + 1;
 218   const uptr kClosedMidEnd = min(kLinuxAppMemBeg, kTraceMemBegin);
 219   ProtectRange(kClosedLowBeg, kClosedLowEnd);
 220   ProtectRange(kClosedMidBeg, kClosedMidEnd);
 221   DPrintf("kClosedLow   %zx-%zx (%zuGB)\n",
 222       kClosedLowBeg, kClosedLowEnd, (kClosedLowEnd - kClosedLowBeg) >> 30);
 223   DPrintf("kLinuxShadow %zx-%zx (%zuGB)\n",
 224       kLinuxShadowBeg, kLinuxShadowEnd,
 225       (kLinuxShadowEnd - kLinuxShadowBeg) >> 30);
 226   DPrintf("kClosedMid   %zx-%zx (%zuGB)\n",
 227       kClosedMidBeg, kClosedMidEnd, (kClosedMidEnd - kClosedMidBeg) >> 30);
 228   DPrintf("kLinuxAppMem %zx-%zx (%zuGB)\n",
 229       kLinuxAppMemBeg, kLinuxAppMemEnd,
 230       (kLinuxAppMemEnd - kLinuxAppMemBeg) >> 30);
 231   DPrintf("stack        %zx\n", (uptr)&shadow);
 232
 233   MapRodata();
 234 }
 235 #endif
 236
 237 static uptr g_data_start;
 238 static uptr g_data_end;
 239
 240 #ifndef TSAN_GO
 241 static void CheckPIE() {
 242   // Ensure that the binary is indeed compiled with -pie.
 243   MemoryMappingLayout proc_maps(true);
 244   uptr start, end;
 245   if (proc_maps.Next(&start, &end,
 246                      /*offset*/0, /*filename*/0, /*filename_size*/0,
 247                      /*protection*/0)) {
 248     if ((u64)start < kLinuxAppMemBeg) {
 249       Printf("FATAL: ThreadSanitizer can not mmap the shadow memory ("
 250              "something is mapped at 0x%zx < 0x%zx)\n",
 251              start, kLinuxAppMemBeg);
 252       Printf("FATAL: Make sure to compile with -fPIE"
 253              " and to link with -pie.\n");
 254       Die();
 255     }
 256   }
 257 }
 258
 259 static void InitDataSeg() {
 260   MemoryMappingLayout proc_maps(true);
 261   uptr start, end, offset;
 262   char name[128];
 263   bool prev_is_data = false;
 264   while (proc_maps.Next(&start, &end, &offset, name, ARRAY_SIZE(name),
 265                         /*protection*/ 0)) {
 266     DPrintf("%p-%p %p %s\n", start, end, offset, name);
 267     bool is_data = offset != 0 && name[0] != 0;
 268     // BSS may get merged with [heap] in /proc/self/maps. This is not very
 269     // reliable.
 270     bool is_bss = offset == 0 &&
 271       (name[0] == 0 || internal_strcmp(name, "[heap]") == 0) && prev_is_data;
 272     if (g_data_start == 0 && is_data)
 273       g_data_start = start;
 274     if (is_bss)
 275       g_data_end = end;
 276     prev_is_data = is_data;
 277   }
 278   DPrintf("guessed data_start=%p data_end=%p\n",  g_data_start, g_data_end);
 279   CHECK_LT(g_data_start, g_data_end);
 280   CHECK_GE((uptr)&g_data_start, g_data_start);
 281   CHECK_LT((uptr)&g_data_start, g_data_end);
 282 }
 283
 284 #endif  // #ifndef TSAN_GO
 285
 286 static rlim_t getlim(int res) {
 287   rlimit rlim;
 288   CHECK_EQ(0, getrlimit(res, &rlim));
 289   return rlim.rlim_cur;
 290 }
 291
 292 static void setlim(int res, rlim_t lim) {
 293   // The following magic is to prevent clang from replacing it with memset.
 294   volatile rlimit rlim;
 295   rlim.rlim_cur = lim;
 296   rlim.rlim_max = lim;
 297   setrlimit(res, (rlimit*)&rlim);
 298 }
 299
 300 const char *InitializePlatform() {
 301   void *p = 0;
 302   if (sizeof(p) == 8) {
 303     // Disable core dumps, dumping of 16TB usually takes a bit long.
 304     setlim(RLIMIT_CORE, 0);
 305   }
 306
 307   // Go maps shadow memory lazily and works fine with limited address space.
 308   // Unlimited stack is not a problem as well, because the executable
 309   // is not compiled with -pie.
 310   if (kCppMode) {
 311     bool reexec = false;
 312     // TSan doesn't play well with unlimited stack size (as stack
 313     // overlaps with shadow memory). If we detect unlimited stack size,
 314     // we re-exec the program with limited stack size as a best effort.
 315     if (getlim(RLIMIT_STACK) == (rlim_t)-1) {
 316       const uptr kMaxStackSize = 32 * 1024 * 1024;
 317       Report("WARNING: Program is run with unlimited stack size, which "
 318              "wouldn't work with ThreadSanitizer.\n");
 319       Report("Re-execing with stack size limited to %zd bytes.\n",
 320              kMaxStackSize);
 321       SetStackSizeLimitInBytes(kMaxStackSize);
 322       reexec = true;
 323     }
 324
 325     if (getlim(RLIMIT_AS) != (rlim_t)-1) {
 326       Report("WARNING: Program is run with limited virtual address space,"
 327              " which wouldn't work with ThreadSanitizer.\n");
 328       Report("Re-execing with unlimited virtual address space.\n");
 329       setlim(RLIMIT_AS, -1);
 330       reexec = true;
 331     }
 332     if (reexec)
 333       ReExec();
 334   }
 335
 336 #ifndef TSAN_GO
 337   CheckPIE();
 338   InitTlsSize();
 339   InitDataSeg();
 340 #endif
 341   return GetEnv(kTsanOptionsEnv);
 342 }
 343
 344 bool IsGlobalVar(uptr addr) {
 345   return g_data_start && addr >= g_data_start && addr < g_data_end;
 346 }
 347
 348 #ifndef TSAN_GO
 349 // Extract file descriptors passed to glibc internal __res_iclose function.
 350 // This is required to properly "close" the fds, because we do not see internal
 351 // closes within glibc. The code is a pure hack.
 352 int ExtractResolvFDs(void *state, int *fds, int nfd) {
 353   int cnt = 0;
 354   __res_state *statp = (__res_state*)state;
 355   for (int i = 0; i < MAXNS && cnt < nfd; i++) {
 356     if (statp->_u._ext.nsaddrs[i] && statp->_u._ext.nssocks[i] != -1)
 357       fds[cnt++] = statp->_u._ext.nssocks[i];
 358   }
 359   return cnt;
 360 }
 361
 362 // Extract file descriptors passed via UNIX domain sockets.
 363 // This is requried to properly handle "open" of these fds.
 364 // see 'man recvmsg' and 'man 3 cmsg'.
 365 int ExtractRecvmsgFDs(void *msgp, int *fds, int nfd) {
 366   int res = 0;
 367   msghdr *msg = (msghdr*)msgp;
 368   struct cmsghdr *cmsg = CMSG_FIRSTHDR(msg);
 369   for (; cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 370     if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS)
 371       continue;
 372     int n = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(fds[0]);
 373     for (int i = 0; i < n; i++) {
 374       fds[res++] = ((int*)CMSG_DATA(cmsg))[i];
 375       if (res == nfd)
 376         return res;
 377     }
 378   }
 379   return res;
 380 }
 381 #endif
 382
 383
 384 }  // namespace __tsan
 385
 386 #endif  // SANITIZER_LINUX