libsanitizer/tsan/tsan_fd.cc

   1 //===-- tsan_fd.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 //===----------------------------------------------------------------------===//
  11
  12 #include "tsan_fd.h"
  13 #include "tsan_rtl.h"
  14 #include <sanitizer_common/sanitizer_atomic.h>
  15
  16 namespace __tsan {
  17
  18 const int kTableSizeL1 = 1024;
  19 const int kTableSizeL2 = 1024;
  20 const int kTableSize = kTableSizeL1 * kTableSizeL2;
  21
  22 struct FdSync {
  23   atomic_uint64_t rc;
  24 };
  25
  26 struct FdDesc {
  27   FdSync *sync;
  28   int creation_tid;
  29   u32 creation_stack;
  30 };
  31
  32 struct FdContext {
  33   atomic_uintptr_t tab[kTableSizeL1];
  34   // Addresses used for synchronization.
  35   FdSync globsync;
  36   FdSync filesync;
  37   FdSync socksync;
  38   u64 connectsync;
  39 };
  40
  41 static FdContext fdctx;
  42
  43 static bool bogusfd(int fd) {
  44   // Apparently a bogus fd value.
  45   return fd < 0 || fd >= kTableSize;
  46 }
  47
  48 static FdSync *allocsync() {
  49   FdSync *s = (FdSync*)internal_alloc(MBlockFD, sizeof(FdSync));
  50   atomic_store(&s->rc, 1, memory_order_relaxed);
  51   return s;
  52 }
  53
  54 static FdSync *ref(FdSync *s) {
  55   if (s && atomic_load(&s->rc, memory_order_relaxed) != (u64)-1)
  56     atomic_fetch_add(&s->rc, 1, memory_order_relaxed);
  57   return s;
  58 }
  59
  60 static void unref(ThreadState *thr, uptr pc, FdSync *s) {
  61   if (s && atomic_load(&s->rc, memory_order_relaxed) != (u64)-1) {
  62     if (atomic_fetch_sub(&s->rc, 1, memory_order_acq_rel) == 1) {
  63       CHECK_NE(s, &fdctx.globsync);
  64       CHECK_NE(s, &fdctx.filesync);
  65       CHECK_NE(s, &fdctx.socksync);
  66       SyncVar *v = ctx->synctab.GetAndRemove(thr, pc, (uptr)s);
  67       if (v)
  68         DestroyAndFree(v);
  69       internal_free(s);
  70     }
  71   }
  72 }
  73
  74 static FdDesc *fddesc(ThreadState *thr, uptr pc, int fd) {
  75   CHECK_GE(fd, 0);
  76   CHECK_LT(fd, kTableSize);
  77   atomic_uintptr_t *pl1 = &fdctx.tab[fd / kTableSizeL2];
  78   uptr l1 = atomic_load(pl1, memory_order_consume);
  79   if (l1 == 0) {
  80     uptr size = kTableSizeL2 * sizeof(FdDesc);
  81     // We need this to reside in user memory to properly catch races on it.
  82     void *p = user_alloc(thr, pc, size);
  83     internal_memset(p, 0, size);
  84     MemoryResetRange(thr, (uptr)&fddesc, (uptr)p, size);
  85     if (atomic_compare_exchange_strong(pl1, &l1, (uptr)p, memory_order_acq_rel))
  86       l1 = (uptr)p;
  87     else
  88       user_free(thr, pc, p);
  89   }
  90   return &((FdDesc*)l1)[fd % kTableSizeL2];  // NOLINT
  91 }
  92
  93 // pd must be already ref'ed.
  94 static void init(ThreadState *thr, uptr pc, int fd, FdSync *s) {
  95   FdDesc *d = fddesc(thr, pc, fd);
  96   // As a matter of fact, we don't intercept all close calls.
  97   // See e.g. libc __res_iclose().
  98   if (d->sync) {
  99     unref(thr, pc, d->sync);
 100     d->sync = 0;
 101   }
 102   if (flags()->io_sync == 0) {
 103     unref(thr, pc, s);
 104   } else if (flags()->io_sync == 1) {
 105     d->sync = s;
 106   } else if (flags()->io_sync == 2) {
 107     unref(thr, pc, s);
 108     d->sync = &fdctx.globsync;
 109   }
 110   d->creation_tid = thr->tid;
 111   d->creation_stack = CurrentStackId(thr, pc);
 112   // To catch races between fd usage and open.
 113   MemoryRangeImitateWrite(thr, pc, (uptr)d, 8);
 114 }
 115
 116 void FdInit() {
 117   atomic_store(&fdctx.globsync.rc, (u64)-1, memory_order_relaxed);
 118   atomic_store(&fdctx.filesync.rc, (u64)-1, memory_order_relaxed);
 119   atomic_store(&fdctx.socksync.rc, (u64)-1, memory_order_relaxed);
 120 }
 121
 122 void FdOnFork(ThreadState *thr, uptr pc) {
 123   // On fork() we need to reset all fd's, because the child is going
 124   // close all them, and that will cause races between previous read/write
 125   // and the close.
 126   for (int l1 = 0; l1 < kTableSizeL1; l1++) {
 127     FdDesc *tab = (FdDesc*)atomic_load(&fdctx.tab[l1], memory_order_relaxed);
 128     if (tab == 0)
 129       break;
 130     for (int l2 = 0; l2 < kTableSizeL2; l2++) {
 131       FdDesc *d = &tab[l2];
 132       MemoryResetRange(thr, pc, (uptr)d, 8);
 133     }
 134   }
 135 }
 136
 137 bool FdLocation(uptr addr, int *fd, int *tid, u32 *stack) {
 138   for (int l1 = 0; l1 < kTableSizeL1; l1++) {
 139     FdDesc *tab = (FdDesc*)atomic_load(&fdctx.tab[l1], memory_order_relaxed);
 140     if (tab == 0)
 141       break;
 142     if (addr >= (uptr)tab && addr < (uptr)(tab + kTableSizeL2)) {
 143       int l2 = (addr - (uptr)tab) / sizeof(FdDesc);
 144       FdDesc *d = &tab[l2];
 145       *fd = l1 * kTableSizeL1 + l2;
 146       *tid = d->creation_tid;
 147       *stack = d->creation_stack;
 148       return true;
 149     }
 150   }
 151   return false;
 152 }
 153
 154 void FdAcquire(ThreadState *thr, uptr pc, int fd) {
 155   if (bogusfd(fd))
 156     return;
 157   FdDesc *d = fddesc(thr, pc, fd);
 158   FdSync *s = d->sync;
 159   DPrintf("#%d: FdAcquire(%d) -> %p\n", thr->tid, fd, s);
 160   MemoryRead(thr, pc, (uptr)d, kSizeLog8);
 161   if (s)
 162     Acquire(thr, pc, (uptr)s);
 163 }
 164
 165 void FdRelease(ThreadState *thr, uptr pc, int fd) {
 166   if (bogusfd(fd))
 167     return;
 168   FdDesc *d = fddesc(thr, pc, fd);
 169   FdSync *s = d->sync;
 170   DPrintf("#%d: FdRelease(%d) -> %p\n", thr->tid, fd, s);
 171   MemoryRead(thr, pc, (uptr)d, kSizeLog8);
 172   if (s)
 173     Release(thr, pc, (uptr)s);
 174 }
 175
 176 void FdAccess(ThreadState *thr, uptr pc, int fd) {
 177   DPrintf("#%d: FdAccess(%d)\n", thr->tid, fd);
 178   if (bogusfd(fd))
 179     return;
 180   FdDesc *d = fddesc(thr, pc, fd);
 181   MemoryRead(thr, pc, (uptr)d, kSizeLog8);
 182 }
 183
 184 void FdClose(ThreadState *thr, uptr pc, int fd) {
 185   DPrintf("#%d: FdClose(%d)\n", thr->tid, fd);
 186   if (bogusfd(fd))
 187     return;
 188   FdDesc *d = fddesc(thr, pc, fd);
 189   // To catch races between fd usage and close.
 190   MemoryWrite(thr, pc, (uptr)d, kSizeLog8);
 191   // We need to clear it, because if we do not intercept any call out there
 192   // that creates fd, we will hit false postives.
 193   MemoryResetRange(thr, pc, (uptr)d, 8);
 194   unref(thr, pc, d->sync);
 195   d->sync = 0;
 196   d->creation_tid = 0;
 197   d->creation_stack = 0;
 198 }
 199
 200 void FdFileCreate(ThreadState *thr, uptr pc, int fd) {
 201   DPrintf("#%d: FdFileCreate(%d)\n", thr->tid, fd);
 202   if (bogusfd(fd))
 203     return;
 204   init(thr, pc, fd, &fdctx.filesync);
 205 }
 206
 207 void FdDup(ThreadState *thr, uptr pc, int oldfd, int newfd) {
 208   DPrintf("#%d: FdDup(%d, %d)\n", thr->tid, oldfd, newfd);
 209   if (bogusfd(oldfd) || bogusfd(newfd))
 210     return;
 211   // Ignore the case when user dups not yet connected socket.
 212   FdDesc *od = fddesc(thr, pc, oldfd);
 213   MemoryRead(thr, pc, (uptr)od, kSizeLog8);
 214   FdClose(thr, pc, newfd);
 215   init(thr, pc, newfd, ref(od->sync));
 216 }
 217
 218 void FdPipeCreate(ThreadState *thr, uptr pc, int rfd, int wfd) {
 219   DPrintf("#%d: FdCreatePipe(%d, %d)\n", thr->tid, rfd, wfd);
 220   FdSync *s = allocsync();
 221   init(thr, pc, rfd, ref(s));
 222   init(thr, pc, wfd, ref(s));
 223   unref(thr, pc, s);
 224 }
 225
 226 void FdEventCreate(ThreadState *thr, uptr pc, int fd) {
 227   DPrintf("#%d: FdEventCreate(%d)\n", thr->tid, fd);
 228   if (bogusfd(fd))
 229     return;
 230   init(thr, pc, fd, allocsync());
 231 }
 232
 233 void FdSignalCreate(ThreadState *thr, uptr pc, int fd) {
 234   DPrintf("#%d: FdSignalCreate(%d)\n", thr->tid, fd);
 235   if (bogusfd(fd))
 236     return;
 237   init(thr, pc, fd, 0);
 238 }
 239
 240 void FdInotifyCreate(ThreadState *thr, uptr pc, int fd) {
 241   DPrintf("#%d: FdInotifyCreate(%d)\n", thr->tid, fd);
 242   if (bogusfd(fd))
 243     return;
 244   init(thr, pc, fd, 0);
 245 }
 246
 247 void FdPollCreate(ThreadState *thr, uptr pc, int fd) {
 248   DPrintf("#%d: FdPollCreate(%d)\n", thr->tid, fd);
 249   if (bogusfd(fd))
 250     return;
 251   init(thr, pc, fd, allocsync());
 252 }
 253
 254 void FdSocketCreate(ThreadState *thr, uptr pc, int fd) {
 255   DPrintf("#%d: FdSocketCreate(%d)\n", thr->tid, fd);
 256   if (bogusfd(fd))
 257     return;
 258   // It can be a UDP socket.
 259   init(thr, pc, fd, &fdctx.socksync);
 260 }
 261
 262 void FdSocketAccept(ThreadState *thr, uptr pc, int fd, int newfd) {
 263   DPrintf("#%d: FdSocketAccept(%d, %d)\n", thr->tid, fd, newfd);
 264   if (bogusfd(fd))
 265     return;
 266   // Synchronize connect->accept.
 267   Acquire(thr, pc, (uptr)&fdctx.connectsync);
 268   init(thr, pc, newfd, &fdctx.socksync);
 269 }
 270
 271 void FdSocketConnecting(ThreadState *thr, uptr pc, int fd) {
 272   DPrintf("#%d: FdSocketConnecting(%d)\n", thr->tid, fd);
 273   if (bogusfd(fd))
 274     return;
 275   // Synchronize connect->accept.
 276   Release(thr, pc, (uptr)&fdctx.connectsync);
 277 }
 278
 279 void FdSocketConnect(ThreadState *thr, uptr pc, int fd) {
 280   DPrintf("#%d: FdSocketConnect(%d)\n", thr->tid, fd);
 281   if (bogusfd(fd))
 282     return;
 283   init(thr, pc, fd, &fdctx.socksync);
 284 }
 285
 286 uptr File2addr(const char *path) {
 287   (void)path;
 288   static u64 addr;
 289   return (uptr)&addr;
 290 }
 291
 292 uptr Dir2addr(const char *path) {
 293   (void)path;
 294   static u64 addr;
 295   return (uptr)&addr;
 296 }
 297
 298 }  //  namespace __tsan