Imported Upstream version 3.9.4upstream/3.9.4

1 files changed, 1326 insertions, 0 deletions

diff --git a/Utilities/cmlibuv/src/unix/core.c b/Utilities/cmlibuv/src/unix/core.c
new file mode 100644
index 000000000..30cdaef7b
--- /dev/null
+++ b/Utilities/cmlibuv/src/unix/core.c
@@ -0,0 +1,1326 @@
+/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "uv.h"
+#include "internal.h"
+
+#include <stddef.h> /* NULL */
+#include <stdio.h> /* printf */
+#include <stdlib.h>
+#include <string.h> /* strerror */
+#include <errno.h>
+#include <assert.h>
+#include <unistd.h>
+#include <sys/param.h> /* MAXHOSTNAMELEN on Linux and the BSDs */
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <limits.h> /* INT_MAX, PATH_MAX, IOV_MAX */
+#include <sys/uio.h> /* writev */
+#include <sys/resource.h> /* getrusage */
+#include <pwd.h>
+
+#ifdef __sun
+# include <netdb.h> /* MAXHOSTNAMELEN on Solaris */
+# include <sys/filio.h>
+# include <sys/types.h>
+# include <sys/wait.h>
+#endif
+
+#ifdef __APPLE__
+# include <mach-o/dyld.h> /* _NSGetExecutablePath */
+# include <sys/filio.h>
+# if defined(O_CLOEXEC)
+#  define UV__O_CLOEXEC O_CLOEXEC
+# endif
+#endif
+
+#if defined(__DragonFly__)      || \
+    defined(__FreeBSD__)        || \
+    defined(__FreeBSD_kernel__)
+# include <sys/sysctl.h>
+# include <sys/filio.h>
+# include <sys/wait.h>
+# define UV__O_CLOEXEC O_CLOEXEC
+# if defined(__FreeBSD__) && __FreeBSD__ >= 10
+#  define uv__accept4 accept4
+#  define UV__SOCK_NONBLOCK SOCK_NONBLOCK
+#  define UV__SOCK_CLOEXEC  SOCK_CLOEXEC
+# endif
+# if !defined(F_DUP2FD_CLOEXEC) && defined(_F_DUP2FD_CLOEXEC)
+#  define F_DUP2FD_CLOEXEC  _F_DUP2FD_CLOEXEC
+# endif
+#endif
+
+#if defined(__ANDROID_API__) && __ANDROID_API__ < 21
+# include <dlfcn.h>  /* for dlsym */
+#endif
+
+#if defined(__MVS__)
+#include <sys/ioctl.h>
+#endif
+
+/* Fallback for the maximum hostname length */
+#ifndef MAXHOSTNAMELEN
+# define MAXHOSTNAMELEN 256
+#endif
+
+static int uv__run_pending(uv_loop_t* loop);
+
+/* Verify that uv_buf_t is ABI-compatible with struct iovec. */
+STATIC_ASSERT(sizeof(uv_buf_t) == sizeof(struct iovec));
+STATIC_ASSERT(sizeof(&((uv_buf_t*) 0)->base) ==
+              sizeof(((struct iovec*) 0)->iov_base));
+STATIC_ASSERT(sizeof(&((uv_buf_t*) 0)->len) ==
+              sizeof(((struct iovec*) 0)->iov_len));
+STATIC_ASSERT(offsetof(uv_buf_t, base) == offsetof(struct iovec, iov_base));
+STATIC_ASSERT(offsetof(uv_buf_t, len) == offsetof(struct iovec, iov_len));
+
+
+uint64_t uv_hrtime(void) {
+  return uv__hrtime(UV_CLOCK_PRECISE);
+}
+
+
+void uv_close(uv_handle_t* handle, uv_close_cb close_cb) {
+  assert(!uv__is_closing(handle));
+
+  handle->flags |= UV_CLOSING;
+  handle->close_cb = close_cb;
+
+  switch (handle->type) {
+  case UV_NAMED_PIPE:
+    uv__pipe_close((uv_pipe_t*)handle);
+    break;
+
+  case UV_TTY:
+    uv__stream_close((uv_stream_t*)handle);
+    break;
+
+  case UV_TCP:
+    uv__tcp_close((uv_tcp_t*)handle);
+    break;
+
+  case UV_UDP:
+    uv__udp_close((uv_udp_t*)handle);
+    break;
+
+  case UV_PREPARE:
+    uv__prepare_close((uv_prepare_t*)handle);
+    break;
+
+  case UV_CHECK:
+    uv__check_close((uv_check_t*)handle);
+    break;
+
+  case UV_IDLE:
+    uv__idle_close((uv_idle_t*)handle);
+    break;
+
+  case UV_ASYNC:
+    uv__async_close((uv_async_t*)handle);
+    break;
+
+  case UV_TIMER:
+    uv__timer_close((uv_timer_t*)handle);
+    break;
+
+  case UV_PROCESS:
+    uv__process_close((uv_process_t*)handle);
+    break;
+
+  case UV_FS_EVENT:
+    uv__fs_event_close((uv_fs_event_t*)handle);
+    break;
+
+  case UV_POLL:
+    uv__poll_close((uv_poll_t*)handle);
+    break;
+
+  case UV_FS_POLL:
+    uv__fs_poll_close((uv_fs_poll_t*)handle);
+    break;
+
+  case UV_SIGNAL:
+    uv__signal_close((uv_signal_t*) handle);
+    /* Signal handles may not be closed immediately. The signal code will */
+    /* itself close uv__make_close_pending whenever appropriate. */
+    return;
+
+  default:
+    assert(0);
+  }
+
+  uv__make_close_pending(handle);
+}
+
+int uv__socket_sockopt(uv_handle_t* handle, int optname, int* value) {
+  int r;
+  int fd;
+  socklen_t len;
+
+  if (handle == NULL || value == NULL)
+    return -EINVAL;
+
+  if (handle->type == UV_TCP || handle->type == UV_NAMED_PIPE)
+    fd = uv__stream_fd((uv_stream_t*) handle);
+  else if (handle->type == UV_UDP)
+    fd = ((uv_udp_t *) handle)->io_watcher.fd;
+  else
+    return -ENOTSUP;
+
+  len = sizeof(*value);
+
+  if (*value == 0)
+    r = getsockopt(fd, SOL_SOCKET, optname, value, &len);
+  else
+    r = setsockopt(fd, SOL_SOCKET, optname, (const void*) value, len);
+
+  if (r < 0)
+    return -errno;
+
+  return 0;
+}
+
+void uv__make_close_pending(uv_handle_t* handle) {
+  assert(handle->flags & UV_CLOSING);
+  assert(!(handle->flags & UV_CLOSED));
+  handle->next_closing = handle->loop->closing_handles;
+  handle->loop->closing_handles = handle;
+}
+
+int uv__getiovmax(void) {
+#if defined(IOV_MAX)
+  return IOV_MAX;
+#elif defined(_SC_IOV_MAX)
+  static int iovmax = -1;
+  if (iovmax == -1) {
+    iovmax = sysconf(_SC_IOV_MAX);
+    /* On some embedded devices (arm-linux-uclibc based ip camera),
+     * sysconf(_SC_IOV_MAX) can not get the correct value. The return
+     * value is -1 and the errno is EINPROGRESS. Degrade the value to 1.
+     */
+    if (iovmax == -1) iovmax = 1;
+  }
+  return iovmax;
+#else
+  return 1024;
+#endif
+}
+
+
+static void uv__finish_close(uv_handle_t* handle) {
+  /* Note: while the handle is in the UV_CLOSING state now, it's still possible
+   * for it to be active in the sense that uv__is_active() returns true.
+   * A good example is when the user calls uv_shutdown(), immediately followed
+   * by uv_close(). The handle is considered active at this point because the
+   * completion of the shutdown req is still pending.
+   */
+  assert(handle->flags & UV_CLOSING);
+  assert(!(handle->flags & UV_CLOSED));
+  handle->flags |= UV_CLOSED;
+
+  switch (handle->type) {
+    case UV_PREPARE:
+    case UV_CHECK:
+    case UV_IDLE:
+    case UV_ASYNC:
+    case UV_TIMER:
+    case UV_PROCESS:
+    case UV_FS_EVENT:
+    case UV_FS_POLL:
+    case UV_POLL:
+    case UV_SIGNAL:
+      break;
+
+    case UV_NAMED_PIPE:
+    case UV_TCP:
+    case UV_TTY:
+      uv__stream_destroy((uv_stream_t*)handle);
+      break;
+
+    case UV_UDP:
+      uv__udp_finish_close((uv_udp_t*)handle);
+      break;
+
+    default:
+      assert(0);
+      break;
+  }
+
+  uv__handle_unref(handle);
+  QUEUE_REMOVE(&handle->handle_queue);
+
+  if (handle->close_cb) {
+    handle->close_cb(handle);
+  }
+}
+
+
+static void uv__run_closing_handles(uv_loop_t* loop) {
+  uv_handle_t* p;
+  uv_handle_t* q;
+
+  p = loop->closing_handles;
+  loop->closing_handles = NULL;
+
+  while (p) {
+    q = p->next_closing;
+    uv__finish_close(p);
+    p = q;
+  }
+}
+
+
+int uv_is_closing(const uv_handle_t* handle) {
+  return uv__is_closing(handle);
+}
+
+
+int uv_backend_fd(const uv_loop_t* loop) {
+  return loop->backend_fd;
+}
+
+
+int uv_backend_timeout(const uv_loop_t* loop) {
+  if (loop->stop_flag != 0)
+    return 0;
+
+  if (!uv__has_active_handles(loop) && !uv__has_active_reqs(loop))
+    return 0;
+
+  if (!QUEUE_EMPTY(&loop->idle_handles))
+    return 0;
+
+  if (!QUEUE_EMPTY(&loop->pending_queue))
+    return 0;
+
+  if (loop->closing_handles)
+    return 0;
+
+  return uv__next_timeout(loop);
+}
+
+
+static int uv__loop_alive(const uv_loop_t* loop) {
+  return uv__has_active_handles(loop) ||
+         uv__has_active_reqs(loop) ||
+         loop->closing_handles != NULL;
+}
+
+
+int uv_loop_alive(const uv_loop_t* loop) {
+    return uv__loop_alive(loop);
+}
+
+
+int uv_run(uv_loop_t* loop, uv_run_mode mode) {
+  int timeout;
+  int r;
+  int ran_pending;
+
+  r = uv__loop_alive(loop);
+  if (!r)
+    uv__update_time(loop);
+
+  while (r != 0 && loop->stop_flag == 0) {
+    uv__update_time(loop);
+    uv__run_timers(loop);
+    ran_pending = uv__run_pending(loop);
+    uv__run_idle(loop);
+    uv__run_prepare(loop);
+
+    timeout = 0;
+    if ((mode == UV_RUN_ONCE && !ran_pending) || mode == UV_RUN_DEFAULT)
+      timeout = uv_backend_timeout(loop);
+
+    uv__io_poll(loop, timeout);
+    uv__run_check(loop);
+    uv__run_closing_handles(loop);
+
+    if (mode == UV_RUN_ONCE) {
+      /* UV_RUN_ONCE implies forward progress: at least one callback must have
+       * been invoked when it returns. uv__io_poll() can return without doing
+       * I/O (meaning: no callbacks) when its timeout expires - which means we
+       * have pending timers that satisfy the forward progress constraint.
+       *
+       * UV_RUN_NOWAIT makes no guarantees about progress so it's omitted from
+       * the check.
+       */
+      uv__update_time(loop);
+      uv__run_timers(loop);
+    }
+
+    r = uv__loop_alive(loop);
+    if (mode == UV_RUN_ONCE || mode == UV_RUN_NOWAIT)
+      break;
+  }
+
+  /* The if statement lets gcc compile it to a conditional store. Avoids
+   * dirtying a cache line.
+   */
+  if (loop->stop_flag != 0)
+    loop->stop_flag = 0;
+
+  return r;
+}
+
+
+void uv_update_time(uv_loop_t* loop) {
+  uv__update_time(loop);
+}
+
+
+int uv_is_active(const uv_handle_t* handle) {
+  return uv__is_active(handle);
+}
+
+
+/* Open a socket in non-blocking close-on-exec mode, atomically if possible. */
+int uv__socket(int domain, int type, int protocol) {
+  int sockfd;
+  int err;
+
+#if defined(SOCK_NONBLOCK) && defined(SOCK_CLOEXEC)
+  sockfd = socket(domain, type | SOCK_NONBLOCK | SOCK_CLOEXEC, protocol);
+  if (sockfd != -1)
+    return sockfd;
+
+  if (errno != EINVAL)
+    return -errno;
+#endif
+
+  sockfd = socket(domain, type, protocol);
+  if (sockfd == -1)
+    return -errno;
+
+  err = uv__nonblock(sockfd, 1);
+  if (err == 0)
+    err = uv__cloexec(sockfd, 1);
+
+  if (err) {
+    uv__close(sockfd);
+    return err;
+  }
+
+#if defined(SO_NOSIGPIPE)
+  {
+    int on = 1;
+    setsockopt(sockfd, SOL_SOCKET, SO_NOSIGPIPE, &on, sizeof(on));
+  }
+#endif
+
+  return sockfd;
+}
+
+/* get a file pointer to a file in read-only and close-on-exec mode */
+FILE* uv__open_file(const char* path) {
+  int fd;
+  FILE* fp;
+
+  fd = uv__open_cloexec(path, O_RDONLY);
+  if (fd < 0)
+    return NULL;
+
+   fp = fdopen(fd, "r");
+   if (fp == NULL)
+     uv__close(fd);
+
+   return fp;
+}
+
+
+int uv__accept(int sockfd) {
+  int peerfd;
+  int err;
+
+  assert(sockfd >= 0);
+
+  while (1) {
+#if defined(__linux__) || (defined(__FreeBSD__) && __FreeBSD__ >= 10)
+    static int no_accept4;
+
+    if (no_accept4)
+      goto skip;
+
+    peerfd = uv__accept4(sockfd,
+                         NULL,
+                         NULL,
+                         UV__SOCK_NONBLOCK|UV__SOCK_CLOEXEC);
+    if (peerfd != -1)
+      return peerfd;
+
+    if (errno == EINTR)
+      continue;
+
+    if (errno != ENOSYS)
+      return -errno;
+
+    no_accept4 = 1;
+skip:
+#endif
+
+    peerfd = accept(sockfd, NULL, NULL);
+    if (peerfd == -1) {
+      if (errno == EINTR)
+        continue;
+      return -errno;
+    }
+
+    err = uv__cloexec(peerfd, 1);
+    if (err == 0)
+      err = uv__nonblock(peerfd, 1);
+
+    if (err) {
+      uv__close(peerfd);
+      return err;
+    }
+
+    return peerfd;
+  }
+}
+
+
+int uv__close_nocheckstdio(int fd) {
+  int saved_errno;
+  int rc;
+
+  assert(fd > -1);  /* Catch uninitialized io_watcher.fd bugs. */
+
+  saved_errno = errno;
+  rc = close(fd);
+  if (rc == -1) {
+    rc = -errno;
+    if (rc == -EINTR || rc == -EINPROGRESS)
+      rc = 0;    /* The close is in progress, not an error. */
+    errno = saved_errno;
+  }
+
+  return rc;
+}
+
+
+int uv__close(int fd) {
+  assert(fd > STDERR_FILENO);  /* Catch stdio close bugs. */
+#if defined(__MVS__)
+  epoll_file_close(fd);
+#endif
+  return uv__close_nocheckstdio(fd);
+}
+
+
+int uv__nonblock_ioctl(int fd, int set) {
+  int r;
+
+  do
+    r = ioctl(fd, FIONBIO, &set);
+  while (r == -1 && errno == EINTR);
+
+  if (r)
+    return -errno;
+
+  return 0;
+}
+
+
+#if !defined(__CYGWIN__) && !defined(__MSYS__)
+int uv__cloexec_ioctl(int fd, int set) {
+  int r;
+
+  do
+    r = ioctl(fd, set ? FIOCLEX : FIONCLEX);
+  while (r == -1 && errno == EINTR);
+
+  if (r)
+    return -errno;
+
+  return 0;
+}
+#endif
+
+
+int uv__nonblock_fcntl(int fd, int set) {
+  int flags;
+  int r;
+
+  do
+    r = fcntl(fd, F_GETFL);
+  while (r == -1 && errno == EINTR);
+
+  if (r == -1)
+    return -errno;
+
+  /* Bail out now if already set/clear. */
+  if (!!(r & O_NONBLOCK) == !!set)
+    return 0;
+
+  if (set)
+    flags = r | O_NONBLOCK;
+  else
+    flags = r & ~O_NONBLOCK;
+
+  do
+    r = fcntl(fd, F_SETFL, flags);
+  while (r == -1 && errno == EINTR);
+
+  if (r)
+    return -errno;
+
+  return 0;
+}
+
+
+int uv__cloexec_fcntl(int fd, int set) {
+  int flags;
+  int r;
+
+  do
+    r = fcntl(fd, F_GETFD);
+  while (r == -1 && errno == EINTR);
+
+  if (r == -1)
+    return -errno;
+
+  /* Bail out now if already set/clear. */
+  if (!!(r & FD_CLOEXEC) == !!set)
+    return 0;
+
+  if (set)
+    flags = r | FD_CLOEXEC;
+  else
+    flags = r & ~FD_CLOEXEC;
+
+  do
+    r = fcntl(fd, F_SETFD, flags);
+  while (r == -1 && errno == EINTR);
+
+  if (r)
+    return -errno;
+
+  return 0;
+}
+
+
+/* This function is not execve-safe, there is a race window
+ * between the call to dup() and fcntl(FD_CLOEXEC).
+ */
+int uv__dup(int fd) {
+  int err;
+
+  fd = dup(fd);
+
+  if (fd == -1)
+    return -errno;
+
+  err = uv__cloexec(fd, 1);
+  if (err) {
+    uv__close(fd);
+    return err;
+  }
+
+  return fd;
+}
+
+
+ssize_t uv__recvmsg(int fd, struct msghdr* msg, int flags) {
+  struct cmsghdr* cmsg;
+  ssize_t rc;
+  int* pfd;
+  int* end;
+#if defined(__linux__)
+  static int no_msg_cmsg_cloexec;
+  if (no_msg_cmsg_cloexec == 0) {
+    rc = recvmsg(fd, msg, flags | 0x40000000);  /* MSG_CMSG_CLOEXEC */
+    if (rc != -1)
+      return rc;
+    if (errno != EINVAL)
+      return -errno;
+    rc = recvmsg(fd, msg, flags);
+    if (rc == -1)
+      return -errno;
+    no_msg_cmsg_cloexec = 1;
+  } else {
+    rc = recvmsg(fd, msg, flags);
+  }
+#else
+  rc = recvmsg(fd, msg, flags);
+#endif
+  if (rc == -1)
+    return -errno;
+  if (msg->msg_controllen == 0)
+    return rc;
+  for (cmsg = CMSG_FIRSTHDR(msg); cmsg != NULL; cmsg = CMSG_NXTHDR(msg, cmsg))
+    if (cmsg->cmsg_type == SCM_RIGHTS)
+      for (pfd = (int*) CMSG_DATA(cmsg),
+           end = (int*) ((char*) cmsg + cmsg->cmsg_len);
+           pfd < end;
+           pfd += 1)
+        uv__cloexec(*pfd, 1);
+  return rc;
+}
+
+
+int uv_cwd(char* buffer, size_t* size) {
+  if (buffer == NULL || size == NULL)
+    return -EINVAL;
+
+  if (getcwd(buffer, *size) == NULL)
+    return -errno;
+
+  *size = strlen(buffer);
+  if (*size > 1 && buffer[*size - 1] == '/') {
+    buffer[*size-1] = '\0';
+    (*size)--;
+  }
+
+  return 0;
+}
+
+
+int uv_chdir(const char* dir) {
+  if (chdir(dir))
+    return -errno;
+
+  return 0;
+}
+
+
+void uv_disable_stdio_inheritance(void) {
+  int fd;
+
+  /* Set the CLOEXEC flag on all open descriptors. Unconditionally try the
+   * first 16 file descriptors. After that, bail out after the first error.
+   */
+  for (fd = 0; ; fd++)
+    if (uv__cloexec(fd, 1) && fd > 15)
+      break;
+}
+
+
+int uv_fileno(const uv_handle_t* handle, uv_os_fd_t* fd) {
+  int fd_out;
+
+  switch (handle->type) {
+  case UV_TCP:
+  case UV_NAMED_PIPE:
+  case UV_TTY:
+    fd_out = uv__stream_fd((uv_stream_t*) handle);
+    break;
+
+  case UV_UDP:
+    fd_out = ((uv_udp_t *) handle)->io_watcher.fd;
+    break;
+
+  case UV_POLL:
+    fd_out = ((uv_poll_t *) handle)->io_watcher.fd;
+    break;
+
+  default:
+    return -EINVAL;
+  }
+
+  if (uv__is_closing(handle) || fd_out == -1)
+    return -EBADF;
+
+  *fd = fd_out;
+  return 0;
+}
+
+
+static int uv__run_pending(uv_loop_t* loop) {
+  QUEUE* q;
+  QUEUE pq;
+  uv__io_t* w;
+
+  if (QUEUE_EMPTY(&loop->pending_queue))
+    return 0;
+
+  QUEUE_MOVE(&loop->pending_queue, &pq);
+
+  while (!QUEUE_EMPTY(&pq)) {
+    q = QUEUE_HEAD(&pq);
+    QUEUE_REMOVE(q);
+    QUEUE_INIT(q);
+    w = QUEUE_DATA(q, uv__io_t, pending_queue);
+    w->cb(loop, w, POLLOUT);
+  }
+
+  return 1;
+}
+
+
+static unsigned int next_power_of_two(unsigned int val) {
+  val -= 1;
+  val |= val >> 1;
+  val |= val >> 2;
+  val |= val >> 4;
+  val |= val >> 8;
+  val |= val >> 16;
+  val += 1;
+  return val;
+}
+
+static void maybe_resize(uv_loop_t* loop, unsigned int len) {
+  uv__io_t** watchers;
+  void* fake_watcher_list;
+  void* fake_watcher_count;
+  unsigned int nwatchers;
+  unsigned int i;
+
+  if (len <= loop->nwatchers)
+    return;
+
+  /* Preserve fake watcher list and count at the end of the watchers */
+  if (loop->watchers != NULL) {
+    fake_watcher_list = loop->watchers[loop->nwatchers];
+    fake_watcher_count = loop->watchers[loop->nwatchers + 1];
+  } else {
+    fake_watcher_list = NULL;
+    fake_watcher_count = NULL;
+  }
+
+  nwatchers = next_power_of_two(len + 2) - 2;
+  watchers = uv__realloc(loop->watchers,
+                         (nwatchers + 2) * sizeof(loop->watchers[0]));
+
+  if (watchers == NULL)
+    abort();
+  for (i = loop->nwatchers; i < nwatchers; i++)
+    watchers[i] = NULL;
+  watchers[nwatchers] = fake_watcher_list;
+  watchers[nwatchers + 1] = fake_watcher_count;
+
+  loop->watchers = watchers;
+  loop->nwatchers = nwatchers;
+}
+
+
+void uv__io_init(uv__io_t* w, uv__io_cb cb, int fd) {
+  assert(cb != NULL);
+  assert(fd >= -1);
+  QUEUE_INIT(&w->pending_queue);
+  QUEUE_INIT(&w->watcher_queue);
+  w->cb = cb;
+  w->fd = fd;
+  w->events = 0;
+  w->pevents = 0;
+
+#if defined(UV_HAVE_KQUEUE)
+  w->rcount = 0;
+  w->wcount = 0;
+#endif /* defined(UV_HAVE_KQUEUE) */
+}
+
+
+void uv__io_start(uv_loop_t* loop, uv__io_t* w, unsigned int events) {
+  assert(0 == (events & ~(POLLIN | POLLOUT | UV__POLLRDHUP)));
+  assert(0 != events);
+  assert(w->fd >= 0);
+  assert(w->fd < INT_MAX);
+
+  w->pevents |= events;
+  maybe_resize(loop, w->fd + 1);
+
+#if !defined(__sun)
+  /* The event ports backend needs to rearm all file descriptors on each and
+   * every tick of the event loop but the other backends allow us to
+   * short-circuit here if the event mask is unchanged.
+   */
+  if (w->events == w->pevents)
+    return;
+#endif
+
+  if (QUEUE_EMPTY(&w->watcher_queue))
+    QUEUE_INSERT_TAIL(&loop->watcher_queue, &w->watcher_queue);
+
+  if (loop->watchers[w->fd] == NULL) {
+    loop->watchers[w->fd] = w;
+    loop->nfds++;
+  }
+}
+
+
+void uv__io_stop(uv_loop_t* loop, uv__io_t* w, unsigned int events) {
+  assert(0 == (events & ~(POLLIN | POLLOUT | UV__POLLRDHUP)));
+  assert(0 != events);
+
+  if (w->fd == -1)
+    return;
+
+  assert(w->fd >= 0);
+
+  /* Happens when uv__io_stop() is called on a handle that was never started. */
+  if ((unsigned) w->fd >= loop->nwatchers)
+    return;
+
+  w->pevents &= ~events;
+
+  if (w->pevents == 0) {
+    QUEUE_REMOVE(&w->watcher_queue);
+    QUEUE_INIT(&w->watcher_queue);
+
+    if (loop->watchers[w->fd] != NULL) {
+      assert(loop->watchers[w->fd] == w);
+      assert(loop->nfds > 0);
+      loop->watchers[w->fd] = NULL;
+      loop->nfds--;
+      w->events = 0;
+    }
+  }
+  else if (QUEUE_EMPTY(&w->watcher_queue))
+    QUEUE_INSERT_TAIL(&loop->watcher_queue, &w->watcher_queue);
+}
+
+
+void uv__io_close(uv_loop_t* loop, uv__io_t* w) {
+  uv__io_stop(loop, w, POLLIN | POLLOUT | UV__POLLRDHUP);
+  QUEUE_REMOVE(&w->pending_queue);
+
+  /* Remove stale events for this file descriptor */
+  uv__platform_invalidate_fd(loop, w->fd);
+}
+
+
+void uv__io_feed(uv_loop_t* loop, uv__io_t* w) {
+  if (QUEUE_EMPTY(&w->pending_queue))
+    QUEUE_INSERT_TAIL(&loop->pending_queue, &w->pending_queue);
+}
+
+
+int uv__io_active(const uv__io_t* w, unsigned int events) {
+  assert(0 == (events & ~(POLLIN | POLLOUT | UV__POLLRDHUP)));
+  assert(0 != events);
+  return 0 != (w->pevents & events);
+}
+
+
+int uv_getrusage(uv_rusage_t* rusage) {
+  struct rusage usage;
+
+  if (getrusage(RUSAGE_SELF, &usage))
+    return -errno;
+
+  rusage->ru_utime.tv_sec = usage.ru_utime.tv_sec;
+  rusage->ru_utime.tv_usec = usage.ru_utime.tv_usec;
+
+  rusage->ru_stime.tv_sec = usage.ru_stime.tv_sec;
+  rusage->ru_stime.tv_usec = usage.ru_stime.tv_usec;
+
+#if !defined(__MVS__)
+  rusage->ru_maxrss = usage.ru_maxrss;
+  rusage->ru_ixrss = usage.ru_ixrss;
+  rusage->ru_idrss = usage.ru_idrss;
+  rusage->ru_isrss = usage.ru_isrss;
+  rusage->ru_minflt = usage.ru_minflt;
+  rusage->ru_majflt = usage.ru_majflt;
+  rusage->ru_nswap = usage.ru_nswap;
+  rusage->ru_inblock = usage.ru_inblock;
+  rusage->ru_oublock = usage.ru_oublock;
+  rusage->ru_msgsnd = usage.ru_msgsnd;
+  rusage->ru_msgrcv = usage.ru_msgrcv;
+  rusage->ru_nsignals = usage.ru_nsignals;
+  rusage->ru_nvcsw = usage.ru_nvcsw;
+  rusage->ru_nivcsw = usage.ru_nivcsw;
+#endif
+
+  return 0;
+}
+
+
+int uv__open_cloexec(const char* path, int flags) {
+  int err;
+  int fd;
+
+#if defined(UV__O_CLOEXEC)
+  static int no_cloexec;
+
+  if (!no_cloexec) {
+    fd = open(path, flags | UV__O_CLOEXEC);
+    if (fd != -1)
+      return fd;
+
+    if (errno != EINVAL)
+      return -errno;
+
+    /* O_CLOEXEC not supported. */
+    no_cloexec = 1;
+  }
+#endif
+
+  fd = open(path, flags);
+  if (fd == -1)
+    return -errno;
+
+  err = uv__cloexec(fd, 1);
+  if (err) {
+    uv__close(fd);
+    return err;
+  }
+
+  return fd;
+}
+
+
+int uv__dup2_cloexec(int oldfd, int newfd) {
+  int r;
+#if defined(__FreeBSD__) && __FreeBSD__ >= 10
+  r = dup3(oldfd, newfd, O_CLOEXEC);
+  if (r == -1)
+    return -errno;
+  return r;
+#elif defined(__FreeBSD__) && defined(F_DUP2FD_CLOEXEC)
+  r = fcntl(oldfd, F_DUP2FD_CLOEXEC, newfd);
+  if (r != -1)
+    return r;
+  if (errno != EINVAL)
+    return -errno;
+  /* Fall through. */
+#elif defined(__linux__)
+  static int no_dup3;
+  if (!no_dup3) {
+    do
+      r = uv__dup3(oldfd, newfd, UV__O_CLOEXEC);
+    while (r == -1 && errno == EBUSY);
+    if (r != -1)
+      return r;
+    if (errno != ENOSYS)
+      return -errno;
+    /* Fall through. */
+    no_dup3 = 1;
+  }
+#endif
+  {
+    int err;
+    do
+      r = dup2(oldfd, newfd);
+#if defined(__linux__)
+    while (r == -1 && errno == EBUSY);
+#else
+    while (0);  /* Never retry. */
+#endif
+
+    if (r == -1)
+      return -errno;
+
+    err = uv__cloexec(newfd, 1);
+    if (err) {
+      uv__close(newfd);
+      return err;
+    }
+
+    return r;
+  }
+}
+
+
+int uv_os_homedir(char* buffer, size_t* size) {
+  uv_passwd_t pwd;
+  char* buf;
+  size_t len;
+  int r;
+
+  if (buffer == NULL || size == NULL || *size == 0)
+    return -EINVAL;
+
+  /* Check if the HOME environment variable is set first */
+  buf = getenv("HOME");
+
+  if (buf != NULL) {
+    len = strlen(buf);
+
+    if (len >= *size) {
+      *size = len + 1;
+      return -ENOBUFS;
+    }
+
+    memcpy(buffer, buf, len + 1);
+    *size = len;
+
+    return 0;
+  }
+
+  /* HOME is not set, so call uv__getpwuid_r() */
+  r = uv__getpwuid_r(&pwd);
+
+  if (r != 0) {
+    return r;
+  }
+
+  len = strlen(pwd.homedir);
+
+  if (len >= *size) {
+    *size = len + 1;
+    uv_os_free_passwd(&pwd);
+    return -ENOBUFS;
+  }
+
+  memcpy(buffer, pwd.homedir, len + 1);
+  *size = len;
+  uv_os_free_passwd(&pwd);
+
+  return 0;
+}
+
+
+int uv_os_tmpdir(char* buffer, size_t* size) {
+  const char* buf;
+  size_t len;
+
+  if (buffer == NULL || size == NULL || *size == 0)
+    return -EINVAL;
+
+#define CHECK_ENV_VAR(name)                                                   \
+  do {                                                                        \
+    buf = getenv(name);                                                       \
+    if (buf != NULL)                                                          \
+      goto return_buffer;                                                     \
+  }                                                                           \
+  while (0)
+
+  /* Check the TMPDIR, TMP, TEMP, and TEMPDIR environment variables in order */
+  CHECK_ENV_VAR("TMPDIR");
+  CHECK_ENV_VAR("TMP");
+  CHECK_ENV_VAR("TEMP");
+  CHECK_ENV_VAR("TEMPDIR");
+
+#undef CHECK_ENV_VAR
+
+  /* No temp environment variables defined */
+  #if defined(__ANDROID__)
+    buf = "/data/local/tmp";
+  #else
+    buf = "/tmp";
+  #endif
+
+return_buffer:
+  len = strlen(buf);
+
+  if (len >= *size) {
+    *size = len + 1;
+    return -ENOBUFS;
+  }
+
+  /* The returned directory should not have a trailing slash. */
+  if (len > 1 && buf[len - 1] == '/') {
+    len--;
+  }
+
+  memcpy(buffer, buf, len + 1);
+  buffer[len] = '\0';
+  *size = len;
+
+  return 0;
+}
+
+
+int uv__getpwuid_r(uv_passwd_t* pwd) {
+  struct passwd pw;
+  struct passwd* result;
+  char* buf;
+  uid_t uid;
+  size_t bufsize;
+  size_t name_size;
+  size_t homedir_size;
+  size_t shell_size;
+  long initsize;
+  int r;
+#if defined(__ANDROID_API__) && __ANDROID_API__ < 21
+  int (*getpwuid_r)(uid_t, struct passwd*, char*, size_t, struct passwd**);
+
+  getpwuid_r = dlsym(RTLD_DEFAULT, "getpwuid_r");
+  if (getpwuid_r == NULL)
+    return -ENOSYS;
+#endif
+
+  if (pwd == NULL)
+    return -EINVAL;
+
+  initsize = sysconf(_SC_GETPW_R_SIZE_MAX);
+
+  if (initsize <= 0)
+    bufsize = 4096;
+  else
+    bufsize = (size_t) initsize;
+
+  uid = geteuid();
+  buf = NULL;
+
+  for (;;) {
+    uv__free(buf);
+    buf = uv__malloc(bufsize);
+
+    if (buf == NULL)
+      return -ENOMEM;
+
+    r = getpwuid_r(uid, &pw, buf, bufsize, &result);
+
+    if (r != ERANGE)
+      break;
+
+    bufsize *= 2;
+  }
+
+  if (r != 0) {
+    uv__free(buf);
+    return -r;
+  }
+
+  if (result == NULL) {
+    uv__free(buf);
+    return -ENOENT;
+  }
+
+  /* Allocate memory for the username, shell, and home directory */
+  name_size = strlen(pw.pw_name) + 1;
+  homedir_size = strlen(pw.pw_dir) + 1;
+  shell_size = strlen(pw.pw_shell) + 1;
+  pwd->username = uv__malloc(name_size + homedir_size + shell_size);
+
+  if (pwd->username == NULL) {
+    uv__free(buf);
+    return -ENOMEM;
+  }
+
+  /* Copy the username */
+  memcpy(pwd->username, pw.pw_name, name_size);
+
+  /* Copy the home directory */
+  pwd->homedir = pwd->username + name_size;
+  memcpy(pwd->homedir, pw.pw_dir, homedir_size);
+
+  /* Copy the shell */
+  pwd->shell = pwd->homedir + homedir_size;
+  memcpy(pwd->shell, pw.pw_shell, shell_size);
+
+  /* Copy the uid and gid */
+  pwd->uid = pw.pw_uid;
+  pwd->gid = pw.pw_gid;
+
+  uv__free(buf);
+
+  return 0;
+}
+
+
+void uv_os_free_passwd(uv_passwd_t* pwd) {
+  if (pwd == NULL)
+    return;
+
+  /*
+    The memory for name, shell, and homedir are allocated in a single
+    uv__malloc() call. The base of the pointer is stored in pwd->username, so
+    that is the field that needs to be freed.
+  */
+  uv__free(pwd->username);
+  pwd->username = NULL;
+  pwd->shell = NULL;
+  pwd->homedir = NULL;
+}
+
+
+int uv_os_get_passwd(uv_passwd_t* pwd) {
+  return uv__getpwuid_r(pwd);
+}
+
+
+int uv_translate_sys_error(int sys_errno) {
+  /* If < 0 then it's already a libuv error. */
+  return sys_errno <= 0 ? sys_errno : -sys_errno;
+}
+
+
+int uv_os_getenv(const char* name, char* buffer, size_t* size) {
+  char* var;
+  size_t len;
+
+  if (name == NULL || buffer == NULL || size == NULL || *size == 0)
+    return -EINVAL;
+
+  var = getenv(name);
+
+  if (var == NULL)
+    return -ENOENT;
+
+  len = strlen(var);
+
+  if (len >= *size) {
+    *size = len + 1;
+    return -ENOBUFS;
+  }
+
+  memcpy(buffer, var, len + 1);
+  *size = len;
+
+  return 0;
+}
+
+
+int uv_os_setenv(const char* name, const char* value) {
+  if (name == NULL || value == NULL)
+    return -EINVAL;
+
+  if (setenv(name, value, 1) != 0)
+    return -errno;
+
+  return 0;
+}
+
+
+int uv_os_unsetenv(const char* name) {
+  if (unsetenv(name) != 0)
+    return -errno;
+
+  return 0;
+}
+
+
+int uv_os_gethostname(char* buffer, size_t* size) {
+  /*
+    On some platforms, if the input buffer is not large enough, gethostname()
+    succeeds, but truncates the result. libuv can detect this and return ENOBUFS
+    instead by creating a large enough buffer and comparing the hostname length
+    to the size input.
+  */
+  char buf[MAXHOSTNAMELEN + 1];
+  size_t len;
+
+  if (buffer == NULL || size == NULL || *size == 0)
+    return -EINVAL;
+
+  if (gethostname(buf, sizeof(buf)) != 0)
+    return -errno;
+
+  buf[sizeof(buf) - 1] = '\0'; /* Null terminate, just to be safe. */
+  len = strlen(buf);
+
+  if (len >= *size) {
+    *size = len + 1;
+    return -ENOBUFS;
+  }
+
+  memcpy(buffer, buf, len + 1);
+  *size = len;
+  return 0;
+}