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-rw-r--r--lib/tsan/rtl/tsan_fd.cpp316
1 files changed, 316 insertions, 0 deletions
diff --git a/lib/tsan/rtl/tsan_fd.cpp b/lib/tsan/rtl/tsan_fd.cpp
new file mode 100644
index 000000000000..50a6b56916aa
--- /dev/null
+++ b/lib/tsan/rtl/tsan_fd.cpp
@@ -0,0 +1,316 @@
+//===-- tsan_fd.cpp -------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of ThreadSanitizer (TSan), a race detector.
+//
+//===----------------------------------------------------------------------===//
+
+#include "tsan_fd.h"
+#include "tsan_rtl.h"
+#include <sanitizer_common/sanitizer_atomic.h>
+
+namespace __tsan {
+
+const int kTableSizeL1 = 1024;
+const int kTableSizeL2 = 1024;
+const int kTableSize = kTableSizeL1 * kTableSizeL2;
+
+struct FdSync {
+ atomic_uint64_t rc;
+};
+
+struct FdDesc {
+ FdSync *sync;
+ int creation_tid;
+ u32 creation_stack;
+};
+
+struct FdContext {
+ atomic_uintptr_t tab[kTableSizeL1];
+ // Addresses used for synchronization.
+ FdSync globsync;
+ FdSync filesync;
+ FdSync socksync;
+ u64 connectsync;
+};
+
+static FdContext fdctx;
+
+static bool bogusfd(int fd) {
+ // Apparently a bogus fd value.
+ return fd < 0 || fd >= kTableSize;
+}
+
+static FdSync *allocsync(ThreadState *thr, uptr pc) {
+ FdSync *s = (FdSync*)user_alloc_internal(thr, pc, sizeof(FdSync),
+ kDefaultAlignment, false);
+ atomic_store(&s->rc, 1, memory_order_relaxed);
+ return s;
+}
+
+static FdSync *ref(FdSync *s) {
+ if (s && atomic_load(&s->rc, memory_order_relaxed) != (u64)-1)
+ atomic_fetch_add(&s->rc, 1, memory_order_relaxed);
+ return s;
+}
+
+static void unref(ThreadState *thr, uptr pc, FdSync *s) {
+ if (s && atomic_load(&s->rc, memory_order_relaxed) != (u64)-1) {
+ if (atomic_fetch_sub(&s->rc, 1, memory_order_acq_rel) == 1) {
+ CHECK_NE(s, &fdctx.globsync);
+ CHECK_NE(s, &fdctx.filesync);
+ CHECK_NE(s, &fdctx.socksync);
+ user_free(thr, pc, s, false);
+ }
+ }
+}
+
+static FdDesc *fddesc(ThreadState *thr, uptr pc, int fd) {
+ CHECK_GE(fd, 0);
+ CHECK_LT(fd, kTableSize);
+ atomic_uintptr_t *pl1 = &fdctx.tab[fd / kTableSizeL2];
+ uptr l1 = atomic_load(pl1, memory_order_consume);
+ if (l1 == 0) {
+ uptr size = kTableSizeL2 * sizeof(FdDesc);
+ // We need this to reside in user memory to properly catch races on it.
+ void *p = user_alloc_internal(thr, pc, size, kDefaultAlignment, false);
+ internal_memset(p, 0, size);
+ MemoryResetRange(thr, (uptr)&fddesc, (uptr)p, size);
+ if (atomic_compare_exchange_strong(pl1, &l1, (uptr)p, memory_order_acq_rel))
+ l1 = (uptr)p;
+ else
+ user_free(thr, pc, p, false);
+ }
+ FdDesc *fds = reinterpret_cast<FdDesc *>(l1);
+ return &fds[fd % kTableSizeL2];
+}
+
+// pd must be already ref'ed.
+static void init(ThreadState *thr, uptr pc, int fd, FdSync *s,
+ bool write = true) {
+ FdDesc *d = fddesc(thr, pc, fd);
+ // As a matter of fact, we don't intercept all close calls.
+ // See e.g. libc __res_iclose().
+ if (d->sync) {
+ unref(thr, pc, d->sync);
+ d->sync = 0;
+ }
+ if (flags()->io_sync == 0) {
+ unref(thr, pc, s);
+ } else if (flags()->io_sync == 1) {
+ d->sync = s;
+ } else if (flags()->io_sync == 2) {
+ unref(thr, pc, s);
+ d->sync = &fdctx.globsync;
+ }
+ d->creation_tid = thr->tid;
+ d->creation_stack = CurrentStackId(thr, pc);
+ if (write) {
+ // To catch races between fd usage and open.
+ MemoryRangeImitateWrite(thr, pc, (uptr)d, 8);
+ } else {
+ // See the dup-related comment in FdClose.
+ MemoryRead(thr, pc, (uptr)d, kSizeLog8);
+ }
+}
+
+void FdInit() {
+ atomic_store(&fdctx.globsync.rc, (u64)-1, memory_order_relaxed);
+ atomic_store(&fdctx.filesync.rc, (u64)-1, memory_order_relaxed);
+ atomic_store(&fdctx.socksync.rc, (u64)-1, memory_order_relaxed);
+}
+
+void FdOnFork(ThreadState *thr, uptr pc) {
+ // On fork() we need to reset all fd's, because the child is going
+ // close all them, and that will cause races between previous read/write
+ // and the close.
+ for (int l1 = 0; l1 < kTableSizeL1; l1++) {
+ FdDesc *tab = (FdDesc*)atomic_load(&fdctx.tab[l1], memory_order_relaxed);
+ if (tab == 0)
+ break;
+ for (int l2 = 0; l2 < kTableSizeL2; l2++) {
+ FdDesc *d = &tab[l2];
+ MemoryResetRange(thr, pc, (uptr)d, 8);
+ }
+ }
+}
+
+bool FdLocation(uptr addr, int *fd, int *tid, u32 *stack) {
+ for (int l1 = 0; l1 < kTableSizeL1; l1++) {
+ FdDesc *tab = (FdDesc*)atomic_load(&fdctx.tab[l1], memory_order_relaxed);
+ if (tab == 0)
+ break;
+ if (addr >= (uptr)tab && addr < (uptr)(tab + kTableSizeL2)) {
+ int l2 = (addr - (uptr)tab) / sizeof(FdDesc);
+ FdDesc *d = &tab[l2];
+ *fd = l1 * kTableSizeL1 + l2;
+ *tid = d->creation_tid;
+ *stack = d->creation_stack;
+ return true;
+ }
+ }
+ return false;
+}
+
+void FdAcquire(ThreadState *thr, uptr pc, int fd) {
+ if (bogusfd(fd))
+ return;
+ FdDesc *d = fddesc(thr, pc, fd);
+ FdSync *s = d->sync;
+ DPrintf("#%d: FdAcquire(%d) -> %p\n", thr->tid, fd, s);
+ MemoryRead(thr, pc, (uptr)d, kSizeLog8);
+ if (s)
+ Acquire(thr, pc, (uptr)s);
+}
+
+void FdRelease(ThreadState *thr, uptr pc, int fd) {
+ if (bogusfd(fd))
+ return;
+ FdDesc *d = fddesc(thr, pc, fd);
+ FdSync *s = d->sync;
+ DPrintf("#%d: FdRelease(%d) -> %p\n", thr->tid, fd, s);
+ MemoryRead(thr, pc, (uptr)d, kSizeLog8);
+ if (s)
+ Release(thr, pc, (uptr)s);
+}
+
+void FdAccess(ThreadState *thr, uptr pc, int fd) {
+ DPrintf("#%d: FdAccess(%d)\n", thr->tid, fd);
+ if (bogusfd(fd))
+ return;
+ FdDesc *d = fddesc(thr, pc, fd);
+ MemoryRead(thr, pc, (uptr)d, kSizeLog8);
+}
+
+void FdClose(ThreadState *thr, uptr pc, int fd, bool write) {
+ DPrintf("#%d: FdClose(%d)\n", thr->tid, fd);
+ if (bogusfd(fd))
+ return;
+ FdDesc *d = fddesc(thr, pc, fd);
+ if (write) {
+ // To catch races between fd usage and close.
+ MemoryWrite(thr, pc, (uptr)d, kSizeLog8);
+ } else {
+ // This path is used only by dup2/dup3 calls.
+ // We do read instead of write because there is a number of legitimate
+ // cases where write would lead to false positives:
+ // 1. Some software dups a closed pipe in place of a socket before closing
+ // the socket (to prevent races actually).
+ // 2. Some daemons dup /dev/null in place of stdin/stdout.
+ // On the other hand we have not seen cases when write here catches real
+ // bugs.
+ MemoryRead(thr, pc, (uptr)d, kSizeLog8);
+ }
+ // We need to clear it, because if we do not intercept any call out there
+ // that creates fd, we will hit false postives.
+ MemoryResetRange(thr, pc, (uptr)d, 8);
+ unref(thr, pc, d->sync);
+ d->sync = 0;
+ d->creation_tid = 0;
+ d->creation_stack = 0;
+}
+
+void FdFileCreate(ThreadState *thr, uptr pc, int fd) {
+ DPrintf("#%d: FdFileCreate(%d)\n", thr->tid, fd);
+ if (bogusfd(fd))
+ return;
+ init(thr, pc, fd, &fdctx.filesync);
+}
+
+void FdDup(ThreadState *thr, uptr pc, int oldfd, int newfd, bool write) {
+ DPrintf("#%d: FdDup(%d, %d)\n", thr->tid, oldfd, newfd);
+ if (bogusfd(oldfd) || bogusfd(newfd))
+ return;
+ // Ignore the case when user dups not yet connected socket.
+ FdDesc *od = fddesc(thr, pc, oldfd);
+ MemoryRead(thr, pc, (uptr)od, kSizeLog8);
+ FdClose(thr, pc, newfd, write);
+ init(thr, pc, newfd, ref(od->sync), write);
+}
+
+void FdPipeCreate(ThreadState *thr, uptr pc, int rfd, int wfd) {
+ DPrintf("#%d: FdCreatePipe(%d, %d)\n", thr->tid, rfd, wfd);
+ FdSync *s = allocsync(thr, pc);
+ init(thr, pc, rfd, ref(s));
+ init(thr, pc, wfd, ref(s));
+ unref(thr, pc, s);
+}
+
+void FdEventCreate(ThreadState *thr, uptr pc, int fd) {
+ DPrintf("#%d: FdEventCreate(%d)\n", thr->tid, fd);
+ if (bogusfd(fd))
+ return;
+ init(thr, pc, fd, allocsync(thr, pc));
+}
+
+void FdSignalCreate(ThreadState *thr, uptr pc, int fd) {
+ DPrintf("#%d: FdSignalCreate(%d)\n", thr->tid, fd);
+ if (bogusfd(fd))
+ return;
+ init(thr, pc, fd, 0);
+}
+
+void FdInotifyCreate(ThreadState *thr, uptr pc, int fd) {
+ DPrintf("#%d: FdInotifyCreate(%d)\n", thr->tid, fd);
+ if (bogusfd(fd))
+ return;
+ init(thr, pc, fd, 0);
+}
+
+void FdPollCreate(ThreadState *thr, uptr pc, int fd) {
+ DPrintf("#%d: FdPollCreate(%d)\n", thr->tid, fd);
+ if (bogusfd(fd))
+ return;
+ init(thr, pc, fd, allocsync(thr, pc));
+}
+
+void FdSocketCreate(ThreadState *thr, uptr pc, int fd) {
+ DPrintf("#%d: FdSocketCreate(%d)\n", thr->tid, fd);
+ if (bogusfd(fd))
+ return;
+ // It can be a UDP socket.
+ init(thr, pc, fd, &fdctx.socksync);
+}
+
+void FdSocketAccept(ThreadState *thr, uptr pc, int fd, int newfd) {
+ DPrintf("#%d: FdSocketAccept(%d, %d)\n", thr->tid, fd, newfd);
+ if (bogusfd(fd))
+ return;
+ // Synchronize connect->accept.
+ Acquire(thr, pc, (uptr)&fdctx.connectsync);
+ init(thr, pc, newfd, &fdctx.socksync);
+}
+
+void FdSocketConnecting(ThreadState *thr, uptr pc, int fd) {
+ DPrintf("#%d: FdSocketConnecting(%d)\n", thr->tid, fd);
+ if (bogusfd(fd))
+ return;
+ // Synchronize connect->accept.
+ Release(thr, pc, (uptr)&fdctx.connectsync);
+}
+
+void FdSocketConnect(ThreadState *thr, uptr pc, int fd) {
+ DPrintf("#%d: FdSocketConnect(%d)\n", thr->tid, fd);
+ if (bogusfd(fd))
+ return;
+ init(thr, pc, fd, &fdctx.socksync);
+}
+
+uptr File2addr(const char *path) {
+ (void)path;
+ static u64 addr;
+ return (uptr)&addr;
+}
+
+uptr Dir2addr(const char *path) {
+ (void)path;
+ static u64 addr;
+ return (uptr)&addr;
+}
+
+} // namespace __tsan