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- and FreeBSD-specific code.
  11 //===----------------------------------------------------------------------===//
  12
  13
  14 #include "sanitizer_common/sanitizer_platform.h"
  15 #if SANITIZER_LINUX || SANITIZER_FREEBSD
  16
  17 #include "sanitizer_common/sanitizer_common.h"
  18 #include "sanitizer_common/sanitizer_libc.h"
  19 #include "sanitizer_common/sanitizer_posix.h"
  20 #include "sanitizer_common/sanitizer_procmaps.h"
  21 #include "sanitizer_common/sanitizer_stoptheworld.h"
  22 #include "sanitizer_common/sanitizer_stackdepot.h"
  23 #include "tsan_platform.h"
  24 #include "tsan_rtl.h"
  25 #include "tsan_flags.h"
  26
  27 #include <fcntl.h>
  28 #include <pthread.h>
  29 #include <signal.h>
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32 #include <string.h>
  33 #include <stdarg.h>
  34 #include <sys/mman.h>
  35 #include <sys/syscall.h>
  36 #include <sys/socket.h>
  37 #include <sys/time.h>
  38 #include <sys/types.h>
  39 #include <sys/resource.h>
  40 #include <sys/stat.h>
  41 #include <unistd.h>
  42 #include <errno.h>
  43 #include <sched.h>
  44 #include <dlfcn.h>
  45 #if SANITIZER_LINUX
  46 #define __need_res_state
  47 #include <resolv.h>
  48 #endif
  49
  50 #ifdef sa_handler
  51 # undef sa_handler
  52 #endif
  53
  54 #ifdef sa_sigaction
  55 # undef sa_sigaction
  56 #endif
  57
  58 #if SANITIZER_FREEBSD
  59 extern "C" void *__libc_stack_end;
  60 void *__libc_stack_end = 0;
  61 #endif
  62
  63 namespace __tsan {
  64
  65 static uptr g_data_start;
  66 static uptr g_data_end;
  67
  68 enum {
  69   MemTotal  = 0,
  70   MemShadow = 1,
  71   MemMeta   = 2,
  72   MemFile   = 3,
  73   MemMmap   = 4,
  74   MemTrace  = 5,
  75   MemHeap   = 6,
  76   MemOther  = 7,
  77   MemCount  = 8,
  78 };
  79
  80 void FillProfileCallback(uptr p, uptr rss, bool file,
  81                          uptr *mem, uptr stats_size) {
  82   mem[MemTotal] += rss;
  83   if (p >= kShadowBeg && p < kShadowEnd)
  84     mem[MemShadow] += rss;
  85   else if (p >= kMetaShadowBeg && p < kMetaShadowEnd)
  86     mem[MemMeta] += rss;
  87 #ifndef SANITIZER_GO
  88   else if (p >= kHeapMemBeg && p < kHeapMemEnd)
  89     mem[MemHeap] += rss;
  90   else if (p >= kLoAppMemBeg && p < kLoAppMemEnd)
  91     mem[file ? MemFile : MemMmap] += rss;
  92   else if (p >= kHiAppMemBeg && p < kHiAppMemEnd)
  93     mem[file ? MemFile : MemMmap] += rss;
  94 #else
  95   else if (p >= kAppMemBeg && p < kAppMemEnd)
  96     mem[file ? MemFile : MemMmap] += rss;
  97 #endif
  98   else if (p >= kTraceMemBeg && p < kTraceMemEnd)
  99     mem[MemTrace] += rss;
 100   else
 101     mem[MemOther] += rss;
 102 }
 103
 104 void WriteMemoryProfile(char *buf, uptr buf_size, uptr nthread, uptr nlive) {
 105   uptr mem[MemCount] = {};
 106   __sanitizer::GetMemoryProfile(FillProfileCallback, mem, 7);
 107   StackDepotStats *stacks = StackDepotGetStats();
 108   internal_snprintf(buf, buf_size,
 109       "RSS %zd MB: shadow:%zd meta:%zd file:%zd mmap:%zd"
 110       " trace:%zd heap:%zd other:%zd stacks=%zd[%zd] nthr=%zd/%zd\n",
 111       mem[MemTotal] >> 20, mem[MemShadow] >> 20, mem[MemMeta] >> 20,
 112       mem[MemFile] >> 20, mem[MemMmap] >> 20, mem[MemTrace] >> 20,
 113       mem[MemHeap] >> 20, mem[MemOther] >> 20,
 114       stacks->allocated >> 20, stacks->n_uniq_ids,
 115       nlive, nthread);
 116 }
 117
 118 #if SANITIZER_LINUX
 119 void FlushShadowMemoryCallback(
 120     const SuspendedThreadsList &suspended_threads_list,
 121     void *argument) {
 122   FlushUnneededShadowMemory(kShadowBeg, kShadowEnd - kShadowBeg);
 123 }
 124 #endif
 125
 126 void FlushShadowMemory() {
 127 #if SANITIZER_LINUX
 128   StopTheWorld(FlushShadowMemoryCallback, 0);
 129 #endif
 130 }
 131
 132 #ifndef SANITIZER_GO
 133 // Mark shadow for .rodata sections with the special kShadowRodata marker.
 134 // Accesses to .rodata can't race, so this saves time, memory and trace space.
 135 static void MapRodata() {
 136   // First create temp file.
 137   const char *tmpdir = GetEnv("TMPDIR");
 138   if (tmpdir == 0)
 139     tmpdir = GetEnv("TEST_TMPDIR");
 140 #ifdef P_tmpdir
 141   if (tmpdir == 0)
 142     tmpdir = P_tmpdir;
 143 #endif
 144   if (tmpdir == 0)
 145     return;
 146   char name[256];
 147   internal_snprintf(name, sizeof(name), "%s/tsan.rodata.%d",
 148                     tmpdir, (int)internal_getpid());
 149   uptr openrv = internal_open(name, O_RDWR | O_CREAT | O_EXCL, 0600);
 150   if (internal_iserror(openrv))
 151     return;
 152   internal_unlink(name);  // Unlink it now, so that we can reuse the buffer.
 153   fd_t fd = openrv;
 154   // Fill the file with kShadowRodata.
 155   const uptr kMarkerSize = 512 * 1024 / sizeof(u64);
 156   InternalScopedBuffer<u64> marker(kMarkerSize);
 157   // volatile to prevent insertion of memset
 158   for (volatile u64 *p = marker.data(); p < marker.data() + kMarkerSize; p++)
 159     *p = kShadowRodata;
 160   internal_write(fd, marker.data(), marker.size());
 161   // Map the file into memory.
 162   uptr page = internal_mmap(0, GetPageSizeCached(), PROT_READ | PROT_WRITE,
 163                             MAP_PRIVATE | MAP_ANONYMOUS, fd, 0);
 164   if (internal_iserror(page)) {
 165     internal_close(fd);
 166     return;
 167   }
 168   // Map the file into shadow of .rodata sections.
 169   MemoryMappingLayout proc_maps(/*cache_enabled*/true);
 170   uptr start, end, offset, prot;
 171   // Reusing the buffer 'name'.
 172   while (proc_maps.Next(&start, &end, &offset, name, ARRAY_SIZE(name), &prot)) {
 173     if (name[0] != 0 && name[0] != '['
 174         && (prot & MemoryMappingLayout::kProtectionRead)
 175         && (prot & MemoryMappingLayout::kProtectionExecute)
 176         && !(prot & MemoryMappingLayout::kProtectionWrite)
 177         && IsAppMem(start)) {
 178       // Assume it's .rodata
 179       char *shadow_start = (char*)MemToShadow(start);
 180       char *shadow_end = (char*)MemToShadow(end);
 181       for (char *p = shadow_start; p < shadow_end; p += marker.size()) {
 182         internal_mmap(p, Min<uptr>(marker.size(), shadow_end - p),
 183                       PROT_READ, MAP_PRIVATE | MAP_FIXED, fd, 0);
 184       }
 185     }
 186   }
 187   internal_close(fd);
 188 }
 189
 190 void InitializeShadowMemoryPlatform() {
 191   MapRodata();
 192 }
 193
 194 static void InitDataSeg() {
 195   MemoryMappingLayout proc_maps(true);
 196   uptr start, end, offset;
 197   char name[128];
 198 #if SANITIZER_FREEBSD
 199   // On FreeBSD BSS is usually the last block allocated within the
 200   // low range and heap is the last block allocated within the range
 201   // 0x800000000-0x8ffffffff.
 202   while (proc_maps.Next(&start, &end, &offset, name, ARRAY_SIZE(name),
 203                         /*protection*/ 0)) {
 204     DPrintf("%p-%p %p %s\n", start, end, offset, name);
 205     if ((start & 0xffff00000000ULL) == 0 && (end & 0xffff00000000ULL) == 0 &&
 206         name[0] == '\0') {
 207       g_data_start = start;
 208       g_data_end = end;
 209     }
 210   }
 211 #else
 212   bool prev_is_data = false;
 213   while (proc_maps.Next(&start, &end, &offset, name, ARRAY_SIZE(name),
 214                         /*protection*/ 0)) {
 215     DPrintf("%p-%p %p %s\n", start, end, offset, name);
 216     bool is_data = offset != 0 && name[0] != 0;
 217     // BSS may get merged with [heap] in /proc/self/maps. This is not very
 218     // reliable.
 219     bool is_bss = offset == 0 &&
 220       (name[0] == 0 || internal_strcmp(name, "[heap]") == 0) && prev_is_data;
 221     if (g_data_start == 0 && is_data)
 222       g_data_start = start;
 223     if (is_bss)
 224       g_data_end = end;
 225     prev_is_data = is_data;
 226   }
 227 #endif
 228   DPrintf("guessed data_start=%p data_end=%p\n",  g_data_start, g_data_end);
 229   CHECK_LT(g_data_start, g_data_end);
 230   CHECK_GE((uptr)&g_data_start, g_data_start);
 231   CHECK_LT((uptr)&g_data_start, g_data_end);
 232 }
 233
 234 #endif  // #ifndef SANITIZER_GO
 235
 236 void InitializePlatform() {
 237   DisableCoreDumperIfNecessary();
 238
 239   // Go maps shadow memory lazily and works fine with limited address space.
 240   // Unlimited stack is not a problem as well, because the executable
 241   // is not compiled with -pie.
 242   if (kCppMode) {
 243     bool reexec = false;
 244     // TSan doesn't play well with unlimited stack size (as stack
 245     // overlaps with shadow memory). If we detect unlimited stack size,
 246     // we re-exec the program with limited stack size as a best effort.
 247     if (StackSizeIsUnlimited()) {
 248       const uptr kMaxStackSize = 32 * 1024 * 1024;
 249       VReport(1, "Program is run with unlimited stack size, which wouldn't "
 250                  "work with ThreadSanitizer.\n"
 251                  "Re-execing with stack size limited to %zd bytes.\n",
 252               kMaxStackSize);
 253       SetStackSizeLimitInBytes(kMaxStackSize);
 254       reexec = true;
 255     }
 256
 257     if (!AddressSpaceIsUnlimited()) {
 258       Report("WARNING: Program is run with limited virtual address space,"
 259              " which wouldn't work with ThreadSanitizer.\n");
 260       Report("Re-execing with unlimited virtual address space.\n");
 261       SetAddressSpaceUnlimited();
 262       reexec = true;
 263     }
 264     if (reexec)
 265       ReExec();
 266   }
 267
 268 #ifndef SANITIZER_GO
 269   CheckAndProtect();
 270   InitTlsSize();
 271   InitDataSeg();
 272 #endif
 273 }
 274
 275 bool IsGlobalVar(uptr addr) {
 276   return g_data_start && addr >= g_data_start && addr < g_data_end;
 277 }
 278
 279 #ifndef SANITIZER_GO
 280 // Extract file descriptors passed to glibc internal __res_iclose function.
 281 // This is required to properly "close" the fds, because we do not see internal
 282 // closes within glibc. The code is a pure hack.
 283 int ExtractResolvFDs(void *state, int *fds, int nfd) {
 284 #if SANITIZER_LINUX
 285   int cnt = 0;
 286   __res_state *statp = (__res_state*)state;
 287   for (int i = 0; i < MAXNS && cnt < nfd; i++) {
 288     if (statp->_u._ext.nsaddrs[i] && statp->_u._ext.nssocks[i] != -1)
 289       fds[cnt++] = statp->_u._ext.nssocks[i];
 290   }
 291   return cnt;
 292 #else
 293   return 0;
 294 #endif
 295 }
 296
 297 // Extract file descriptors passed via UNIX domain sockets.
 298 // This is requried to properly handle "open" of these fds.
 299 // see 'man recvmsg' and 'man 3 cmsg'.
 300 int ExtractRecvmsgFDs(void *msgp, int *fds, int nfd) {
 301   int res = 0;
 302   msghdr *msg = (msghdr*)msgp;
 303   struct cmsghdr *cmsg = CMSG_FIRSTHDR(msg);
 304   for (; cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 305     if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS)
 306       continue;
 307     int n = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(fds[0]);
 308     for (int i = 0; i < n; i++) {
 309       fds[res++] = ((int*)CMSG_DATA(cmsg))[i];
 310       if (res == nfd)
 311         return res;
 312     }
 313   }
 314   return res;
 315 }
 316
 317 // Note: this function runs with async signals enabled,
 318 // so it must not touch any tsan state.
 319 int call_pthread_cancel_with_cleanup(int(*fn)(void *c, void *m,
 320     void *abstime), void *c, void *m, void *abstime,
 321     void(*cleanup)(void *arg), void *arg) {
 322   // pthread_cleanup_push/pop are hardcore macros mess.
 323   // We can't intercept nor call them w/o including pthread.h.
 324   int res;
 325   pthread_cleanup_push(cleanup, arg);
 326   res = fn(c, m, abstime);
 327   pthread_cleanup_pop(0);
 328   return res;
 329 }
 330 #endif
 331
 332 #ifndef SANITIZER_GO
 333 void ReplaceSystemMalloc() { }
 334 #endif
 335
 336 }  // namespace __tsan
 337
 338 #endif  // SANITIZER_LINUX || SANITIZER_FREEBSD