--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/third_party/libuv/src/unix/fs.c	Wed Jan 14 19:39:52 2026 -0800
@@ -0,0 +1,2303 @@
+/* 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.
+ */
+
+/* Caveat emptor: this file deviates from the libuv convention of returning
+ * negated errno codes. Most uv_fs_*() functions map directly to the system
+ * call of the same name. For more complex wrappers, it's easier to just
+ * return -1 with errno set. The dispatcher in uv__fs_work() takes care of
+ * getting the errno to the right place (req->result or as the return value.)
+ */
+
+#include "uv.h"
+#include "internal.h"
+
+#include <errno.h>
+#include <dlfcn.h>
+#include <stdatomic.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h> /* PATH_MAX */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/uio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <poll.h>
+
+#if defined(__linux__)
+# include <sys/sendfile.h>
+#endif
+
+#if defined(__sun)
+# include <sys/sendfile.h>
+# include <sys/sysmacros.h>
+#endif
+
+#if defined(__APPLE__)
+# include <sys/sysctl.h>
+#elif defined(__linux__) && !defined(FICLONE)
+# include <sys/ioctl.h>
+# define FICLONE _IOW(0x94, 9, int)
+#endif
+
+#if defined(_AIX) && !defined(_AIX71)
+# include <utime.h>
+#endif
+
+#if defined(__APPLE__)            ||                                      \
+    defined(__DragonFly__)        ||                                      \
+    defined(__FreeBSD__)          ||                                      \
+    defined(__OpenBSD__)          ||                                      \
+    defined(__NetBSD__)
+# include <sys/param.h>
+# include <sys/mount.h>
+#elif defined(__sun)      || \
+      defined(__MVS__)    || \
+      defined(__NetBSD__) || \
+      defined(__HAIKU__)  || \
+      defined(__QNX__)
+# include <sys/statvfs.h>
+#else
+# include <sys/statfs.h>
+#endif
+
+#if defined(_AIX) && _XOPEN_SOURCE <= 600
+extern char *mkdtemp(char *template); /* See issue #740 on AIX < 7 */
+#endif
+
+#define INIT(subtype)                                                         \
+  do {                                                                        \
+    if (req == NULL)                                                          \
+      return UV_EINVAL;                                                       \
+    UV_REQ_INIT(req, UV_FS);                                                  \
+    req->fs_type = UV_FS_ ## subtype;                                         \
+    req->result = 0;                                                          \
+    req->ptr = NULL;                                                          \
+    req->loop = loop;                                                         \
+    req->path = NULL;                                                         \
+    req->new_path = NULL;                                                     \
+    req->bufs = NULL;                                                         \
+    req->cb = cb;                                                             \
+  }                                                                           \
+  while (0)
+
+#define PATH                                                                  \
+  do {                                                                        \
+    assert(path != NULL);                                                     \
+    if (cb == NULL) {                                                         \
+      req->path = path;                                                       \
+    } else {                                                                  \
+      req->path = uv__strdup(path);                                           \
+      if (req->path == NULL)                                                  \
+        return UV_ENOMEM;                                                     \
+    }                                                                         \
+  }                                                                           \
+  while (0)
+
+#define PATH2                                                                 \
+  do {                                                                        \
+    if (cb == NULL) {                                                         \
+      req->path = path;                                                       \
+      req->new_path = new_path;                                               \
+    } else {                                                                  \
+      size_t path_len;                                                        \
+      size_t new_path_len;                                                    \
+      path_len = strlen(path) + 1;                                            \
+      new_path_len = strlen(new_path) + 1;                                    \
+      req->path = uv__malloc(path_len + new_path_len);                        \
+      if (req->path == NULL)                                                  \
+        return UV_ENOMEM;                                                     \
+      req->new_path = req->path + path_len;                                   \
+      memcpy((void*) req->path, path, path_len);                              \
+      memcpy((void*) req->new_path, new_path, new_path_len);                  \
+    }                                                                         \
+  }                                                                           \
+  while (0)
+
+#define POST                                                                  \
+  do {                                                                        \
+    if (cb != NULL) {                                                         \
+      uv__req_register(loop);                                                 \
+      uv__work_submit(loop,                                                   \
+                      &req->work_req,                                         \
+                      UV__WORK_FAST_IO,                                       \
+                      uv__fs_work,                                            \
+                      uv__fs_done);                                           \
+      return 0;                                                               \
+    }                                                                         \
+    else {                                                                    \
+      uv__fs_work(&req->work_req);                                            \
+      return req->result;                                                     \
+    }                                                                         \
+  }                                                                           \
+  while (0)
+
+
+static int uv__fs_close(int fd) {
+  int rc;
+
+  rc = uv__close_nocancel(fd);
+  if (rc == -1)
+    if (errno == EINTR || errno == EINPROGRESS)
+      rc = 0;  /* The close is in progress, not an error. */
+
+  return rc;
+}
+
+
+static ssize_t uv__fs_fsync(uv_fs_t* req) {
+#if defined(__APPLE__)
+  /* Apple's fdatasync and fsync explicitly do NOT flush the drive write cache
+   * to the drive platters. This is in contrast to Linux's fdatasync and fsync
+   * which do, according to recent man pages. F_FULLFSYNC is Apple's equivalent
+   * for flushing buffered data to permanent storage. If F_FULLFSYNC is not
+   * supported by the file system we fall back to F_BARRIERFSYNC or fsync().
+   * This is the same approach taken by sqlite, except sqlite does not issue
+   * an F_BARRIERFSYNC call.
+   */
+  int r;
+
+  r = fcntl(req->file, F_FULLFSYNC);
+  if (r != 0)
+    r = fcntl(req->file, 85 /* F_BARRIERFSYNC */);  /* fsync + barrier */
+  if (r != 0)
+    r = fsync(req->file);
+  return r;
+#else
+  return fsync(req->file);
+#endif
+}
+
+
+static ssize_t uv__fs_fdatasync(uv_fs_t* req) {
+#if defined(__linux__) || defined(__sun) || defined(__NetBSD__)
+  return fdatasync(req->file);
+#elif defined(__APPLE__)
+  /* See the comment in uv__fs_fsync. */
+  return uv__fs_fsync(req);
+#else
+  return fsync(req->file);
+#endif
+}
+
+
+#if defined(__APPLE__)                                                        \
+    || defined(_AIX71)                                                        \
+    || defined(__DragonFly__)                                                 \
+    || defined(__FreeBSD__)                                                   \
+    || defined(__HAIKU__)                                                     \
+    || defined(__NetBSD__)                                                    \
+    || defined(__OpenBSD__)                                                   \
+    || defined(__linux__)                                                     \
+    || defined(__sun)
+static struct timespec uv__fs_to_timespec(double time) {
+  struct timespec ts;
+
+  if (uv__isinf(time))
+    return (struct timespec){UTIME_NOW, UTIME_NOW};
+  if (uv__isnan(time))
+    return (struct timespec){UTIME_OMIT, UTIME_OMIT};
+
+  ts.tv_sec  = time;
+  ts.tv_nsec = (time - ts.tv_sec) * 1e9;
+
+ /* TODO(bnoordhuis) Remove this. utimesat() has nanosecond resolution but we
+  * stick to microsecond resolution for the sake of consistency with other
+  * platforms. I'm the original author of this compatibility hack but I'm
+  * less convinced it's useful nowadays.
+  */
+  ts.tv_nsec -= ts.tv_nsec % 1000;
+
+  if (ts.tv_nsec < 0) {
+    ts.tv_nsec += 1e9;
+    ts.tv_sec -= 1;
+  }
+  return ts;
+}
+#endif
+
+
+static ssize_t uv__fs_futime(uv_fs_t* req) {
+#if defined(__APPLE__)                                                        \
+    || defined(_AIX71)                                                        \
+    || defined(__DragonFly__)                                                 \
+    || defined(__FreeBSD__)                                                   \
+    || defined(__HAIKU__)                                                     \
+    || defined(__NetBSD__)                                                    \
+    || defined(__OpenBSD__)                                                   \
+    || defined(__linux__)                                                     \
+    || defined(__sun)
+  struct timespec ts[2];
+  ts[0] = uv__fs_to_timespec(req->atime);
+  ts[1] = uv__fs_to_timespec(req->mtime);
+  return futimens(req->file, ts);
+#elif defined(__MVS__)
+  attrib_t atr;
+  memset(&atr, 0, sizeof(atr));
+  atr.att_mtimechg = 1;
+  atr.att_atimechg = 1;
+  atr.att_mtime = req->mtime;
+  atr.att_atime = req->atime;
+  return __fchattr(req->file, &atr, sizeof(atr));
+#else
+  errno = ENOSYS;
+  return -1;
+#endif
+}
+
+
+static ssize_t uv__fs_mkdtemp(uv_fs_t* req) {
+  return mkdtemp((char*) req->path) ? 0 : -1;
+}
+
+
+static int (*uv__mkostemp)(char*, int);
+
+
+static void uv__mkostemp_initonce(void) {
+  /* z/os doesn't have RTLD_DEFAULT but that's okay
+   * because it doesn't have mkostemp(O_CLOEXEC) either.
+   */
+#ifdef RTLD_DEFAULT
+  uv__mkostemp = (int (*)(char*, int)) dlsym(RTLD_DEFAULT, "mkostemp");
+
+  /* We don't care about errors, but we do want to clean them up.
+   * If there has been no error, then dlerror() will just return
+   * NULL.
+   */
+  dlerror();
+#endif  /* RTLD_DEFAULT */
+}
+
+
+static int uv__fs_mkstemp(uv_fs_t* req) {
+  static uv_once_t once = UV_ONCE_INIT;
+  int r;
+#ifdef O_CLOEXEC
+  static _Atomic int no_cloexec_support;
+#endif
+  static const char pattern[] = "XXXXXX";
+  static const size_t pattern_size = sizeof(pattern) - 1;
+  char* path;
+  size_t path_length;
+
+  path = (char*) req->path;
+  path_length = strlen(path);
+
+  /* EINVAL can be returned for 2 reasons:
+      1. The template's last 6 characters were not XXXXXX
+      2. open() didn't support O_CLOEXEC
+     We want to avoid going to the fallback path in case
+     of 1, so it's manually checked before. */
+  if (path_length < pattern_size ||
+      strcmp(path + path_length - pattern_size, pattern)) {
+    errno = EINVAL;
+    r = -1;
+    goto clobber;
+  }
+
+  uv_once(&once, uv__mkostemp_initonce);
+
+#ifdef O_CLOEXEC
+  if (atomic_load_explicit(&no_cloexec_support, memory_order_relaxed) == 0 &&
+      uv__mkostemp != NULL) {
+    r = uv__mkostemp(path, O_CLOEXEC);
+
+    if (r >= 0)
+      return r;
+
+    /* If mkostemp() returns EINVAL, it means the kernel doesn't
+       support O_CLOEXEC, so we just fallback to mkstemp() below. */
+    if (errno != EINVAL)
+      goto clobber;
+
+    /* We set the static variable so that next calls don't even
+       try to use mkostemp. */
+    atomic_store_explicit(&no_cloexec_support, 1, memory_order_relaxed);
+  }
+#endif  /* O_CLOEXEC */
+
+  if (req->cb != NULL)
+    uv_rwlock_rdlock(&req->loop->cloexec_lock);
+
+  r = mkstemp(path);
+
+  /* In case of failure `uv__cloexec` will leave error in `errno`,
+   * so it is enough to just set `r` to `-1`.
+   */
+  if (r >= 0 && uv__cloexec(r, 1) != 0) {
+    r = uv__close(r);
+    if (r != 0)
+      abort();
+    r = -1;
+  }
+
+  if (req->cb != NULL)
+    uv_rwlock_rdunlock(&req->loop->cloexec_lock);
+
+clobber:
+  if (r < 0)
+    path[0] = '\0';
+  return r;
+}
+
+
+static ssize_t uv__fs_open(uv_fs_t* req) {
+#ifdef O_CLOEXEC
+  return open(req->path, req->flags | O_CLOEXEC, req->mode);
+#else  /* O_CLOEXEC */
+  int r;
+
+  if (req->cb != NULL)
+    uv_rwlock_rdlock(&req->loop->cloexec_lock);
+
+  r = open(req->path, req->flags, req->mode);
+
+  /* In case of failure `uv__cloexec` will leave error in `errno`,
+   * so it is enough to just set `r` to `-1`.
+   */
+  if (r >= 0 && uv__cloexec(r, 1) != 0) {
+    r = uv__close(r);
+    if (r != 0)
+      abort();
+    r = -1;
+  }
+
+  if (req->cb != NULL)
+    uv_rwlock_rdunlock(&req->loop->cloexec_lock);
+
+  return r;
+#endif  /* O_CLOEXEC */
+}
+
+
+static ssize_t uv__preadv_or_pwritev_emul(int fd,
+                                          const struct iovec* bufs,
+                                          size_t nbufs,
+                                          off_t off,
+                                          int is_pread) {
+  ssize_t total;
+  ssize_t r;
+  size_t i;
+  size_t n;
+  void* p;
+
+  total = 0;
+  for (i = 0; i < (size_t) nbufs; i++) {
+    p = bufs[i].iov_base;
+    n = bufs[i].iov_len;
+
+    do
+      if (is_pread)
+        r = pread(fd, p, n, off);
+      else
+        r = pwrite(fd, p, n, off);
+    while (r == -1 && errno == EINTR);
+
+    if (r == -1) {
+      if (total > 0)
+        return total;
+      return -1;
+    }
+
+    off += r;
+    total += r;
+
+    if ((size_t) r < n)
+      return total;
+  }
+
+  return total;
+}
+
+
+#ifdef __linux__
+typedef int uv__iovcnt;
+#else
+typedef size_t uv__iovcnt;
+#endif
+
+
+static ssize_t uv__preadv_emul(int fd,
+                               const struct iovec* bufs,
+                               uv__iovcnt nbufs,
+                               off_t off) {
+  return uv__preadv_or_pwritev_emul(fd, bufs, nbufs, off, /*is_pread*/1);
+}
+
+
+static ssize_t uv__pwritev_emul(int fd,
+                                const struct iovec* bufs,
+                                uv__iovcnt nbufs,
+                                off_t off) {
+  return uv__preadv_or_pwritev_emul(fd, bufs, nbufs, off, /*is_pread*/0);
+}
+
+
+/* The function pointer cache is an uintptr_t because _Atomic void*
+ * doesn't work on macos/ios/etc...
+ */
+static ssize_t uv__preadv_or_pwritev(int fd,
+                                     const struct iovec* bufs,
+                                     size_t nbufs,
+                                     off_t off,
+                                     _Atomic uintptr_t* cache,
+                                     int is_pread) {
+  ssize_t (*f)(int, const struct iovec*, uv__iovcnt, off_t);
+  void* p;
+
+  p = (void*) atomic_load_explicit(cache, memory_order_relaxed);
+  if (p == NULL) {
+#ifdef RTLD_DEFAULT
+    /* Try _LARGEFILE_SOURCE version of preadv/pwritev first,
+     * then fall back to the plain version, for libcs like musl.
+     */
+    p = dlsym(RTLD_DEFAULT, is_pread ? "preadv64" : "pwritev64");
+    if (p == NULL)
+      p = dlsym(RTLD_DEFAULT, is_pread ? "preadv" : "pwritev");
+    dlerror();  /* Clear errors. */
+#endif  /* RTLD_DEFAULT */
+    if (p == NULL)
+      p = is_pread ? uv__preadv_emul : uv__pwritev_emul;
+    atomic_store_explicit(cache, (uintptr_t) p, memory_order_relaxed);
+  }
+
+  f = p;
+  return f(fd, bufs, nbufs, off);
+}
+
+
+static ssize_t uv__preadv(int fd,
+                          const struct iovec* bufs,
+                          size_t nbufs,
+                          off_t off) {
+  static _Atomic uintptr_t cache;
+  return uv__preadv_or_pwritev(fd, bufs, nbufs, off, &cache, /*is_pread*/1);
+}
+
+
+static ssize_t uv__pwritev(int fd,
+                           const struct iovec* bufs,
+                           size_t nbufs,
+                           off_t off) {
+  static _Atomic uintptr_t cache;
+  return uv__preadv_or_pwritev(fd, bufs, nbufs, off, &cache, /*is_pread*/0);
+}
+
+
+static ssize_t uv__fs_read(uv_fs_t* req) {
+  const struct iovec* bufs;
+  unsigned int iovmax;
+  size_t nbufs;
+  ssize_t r;
+  off_t off;
+  int fd;
+
+  fd = req->file;
+  off = req->off;
+  bufs = (const struct iovec*) req->bufs;
+  nbufs = req->nbufs;
+
+  iovmax = uv__getiovmax();
+  if (nbufs > iovmax)
+    nbufs = iovmax;
+
+  r = 0;
+  if (off < 0) {
+    if (nbufs == 1)
+      r = read(fd, bufs->iov_base, bufs->iov_len);
+    else if (nbufs > 1)
+      r = readv(fd, bufs, nbufs);
+  } else {
+    if (nbufs == 1)
+      r = pread(fd, bufs->iov_base, bufs->iov_len, off);
+    else if (nbufs > 1)
+      r = uv__preadv(fd, bufs, nbufs, off);
+  }
+
+#ifdef __PASE__
+  /* PASE returns EOPNOTSUPP when reading a directory, convert to EISDIR */
+  if (r == -1 && errno == EOPNOTSUPP) {
+    struct stat buf;
+    ssize_t rc;
+    rc = uv__fstat(fd, &buf);
+    if (rc == 0 && S_ISDIR(buf.st_mode)) {
+      errno = EISDIR;
+    }
+  }
+#endif
+
+  /* We don't own the buffer list in the synchronous case. */
+  if (req->cb != NULL)
+    if (req->bufs != req->bufsml)
+      uv__free(req->bufs);
+
+  req->bufs = NULL;
+  req->nbufs = 0;
+
+  return r;
+}
+
+
+static int uv__fs_scandir_filter(const uv__dirent_t* dent) {
+  return strcmp(dent->d_name, ".") != 0 && strcmp(dent->d_name, "..") != 0;
+}
+
+
+static int uv__fs_scandir_sort(const uv__dirent_t** a, const uv__dirent_t** b) {
+  return strcmp((*a)->d_name, (*b)->d_name);
+}
+
+
+static ssize_t uv__fs_scandir(uv_fs_t* req) {
+  uv__dirent_t** dents;
+  int n;
+
+  dents = NULL;
+  n = scandir(req->path, &dents, uv__fs_scandir_filter, uv__fs_scandir_sort);
+
+  /* NOTE: We will use nbufs as an index field */
+  req->nbufs = 0;
+
+  if (n == 0) {
+    /* OS X still needs to deallocate some memory.
+     * Memory was allocated using the system allocator, so use free() here.
+     */
+    free(dents);
+    dents = NULL;
+  } else if (n == -1) {
+    return n;
+  }
+
+  req->ptr = dents;
+
+  return n;
+}
+
+static int uv__fs_opendir(uv_fs_t* req) {
+  uv_dir_t* dir;
+
+  dir = uv__malloc(sizeof(*dir));
+  if (dir == NULL)
+    goto error;
+
+  dir->dir = opendir(req->path);
+  if (dir->dir == NULL)
+    goto error;
+
+  req->ptr = dir;
+  return 0;
+
+error:
+  uv__free(dir);
+  req->ptr = NULL;
+  return -1;
+}
+
+static int uv__fs_readdir(uv_fs_t* req) {
+  uv_dir_t* dir;
+  uv_dirent_t* dirent;
+  struct dirent* res;
+  unsigned int dirent_idx;
+  unsigned int i;
+
+  dir = req->ptr;
+  dirent_idx = 0;
+
+  while (dirent_idx < dir->nentries) {
+    /* readdir() returns NULL on end of directory, as well as on error. errno
+       is used to differentiate between the two conditions. */
+    errno = 0;
+    res = readdir(dir->dir);
+
+    if (res == NULL) {
+      if (errno != 0)
+        goto error;
+      break;
+    }
+
+    if (strcmp(res->d_name, ".") == 0 || strcmp(res->d_name, "..") == 0)
+      continue;
+
+    dirent = &dir->dirents[dirent_idx];
+    dirent->name = uv__strdup(res->d_name);
+
+    if (dirent->name == NULL)
+      goto error;
+
+    dirent->type = uv__fs_get_dirent_type(res);
+    ++dirent_idx;
+  }
+
+  return dirent_idx;
+
+error:
+  for (i = 0; i < dirent_idx; ++i) {
+    uv__free((char*) dir->dirents[i].name);
+    dir->dirents[i].name = NULL;
+  }
+
+  return -1;
+}
+
+static int uv__fs_closedir(uv_fs_t* req) {
+  uv_dir_t* dir;
+
+  dir = req->ptr;
+
+  if (dir->dir != NULL) {
+    closedir(dir->dir);
+    dir->dir = NULL;
+  }
+
+  uv__free(req->ptr);
+  req->ptr = NULL;
+  return 0;
+}
+
+static int uv__fs_statfs(uv_fs_t* req) {
+  uv_statfs_t* stat_fs;
+#if defined(__sun)      || \
+    defined(__MVS__)    || \
+    defined(__NetBSD__) || \
+    defined(__HAIKU__)  || \
+    defined(__QNX__)
+  struct statvfs buf;
+
+  if (0 != statvfs(req->path, &buf))
+#else
+  struct statfs buf;
+
+  if (0 != statfs(req->path, &buf))
+#endif /* defined(__sun) */
+    return -1;
+
+  stat_fs = uv__malloc(sizeof(*stat_fs));
+  if (stat_fs == NULL) {
+    errno = ENOMEM;
+    return -1;
+  }
+
+#if defined(__sun)        || \
+    defined(__MVS__)      || \
+    defined(__OpenBSD__)  || \
+    defined(__NetBSD__)   || \
+    defined(__HAIKU__)    || \
+    defined(__QNX__)
+  stat_fs->f_type = 0;  /* f_type is not supported. */
+#else
+  stat_fs->f_type = buf.f_type;
+#endif
+  stat_fs->f_bsize = buf.f_bsize;
+  stat_fs->f_blocks = buf.f_blocks;
+  stat_fs->f_bfree = buf.f_bfree;
+  stat_fs->f_bavail = buf.f_bavail;
+  stat_fs->f_files = buf.f_files;
+  stat_fs->f_ffree = buf.f_ffree;
+  req->ptr = stat_fs;
+  return 0;
+}
+
+static ssize_t uv__fs_pathmax_size(const char* path) {
+  ssize_t pathmax;
+
+  pathmax = pathconf(path, _PC_PATH_MAX);
+
+  if (pathmax == -1)
+    pathmax = UV__PATH_MAX;
+
+  return pathmax;
+}
+
+static ssize_t uv__fs_readlink(uv_fs_t* req) {
+  ssize_t maxlen;
+  ssize_t len;
+  char* buf;
+
+#if defined(_POSIX_PATH_MAX) || defined(PATH_MAX)
+  maxlen = uv__fs_pathmax_size(req->path);
+#else
+  /* We may not have a real PATH_MAX.  Read size of link.  */
+  struct stat st;
+  int ret;
+  ret = uv__lstat(req->path, &st);
+  if (ret != 0)
+    return -1;
+  if (!S_ISLNK(st.st_mode)) {
+    errno = EINVAL;
+    return -1;
+  }
+
+  maxlen = st.st_size;
+
+  /* According to readlink(2) lstat can report st_size == 0
+     for some symlinks, such as those in /proc or /sys.  */
+  if (maxlen == 0)
+    maxlen = uv__fs_pathmax_size(req->path);
+#endif
+
+  buf = uv__malloc(maxlen);
+
+  if (buf == NULL) {
+    errno = ENOMEM;
+    return -1;
+  }
+
+#if defined(__MVS__)
+  len = os390_readlink(req->path, buf, maxlen);
+#else
+  len = readlink(req->path, buf, maxlen);
+#endif
+
+  if (len == -1) {
+    uv__free(buf);
+    return -1;
+  }
+
+  /* Uncommon case: resize to make room for the trailing nul byte. */
+  if (len == maxlen) {
+    buf = uv__reallocf(buf, len + 1);
+
+    if (buf == NULL)
+      return -1;
+  }
+
+  buf[len] = '\0';
+  req->ptr = buf;
+
+  return 0;
+}
+
+static ssize_t uv__fs_realpath(uv_fs_t* req) {
+  char* buf;
+  char* tmp;
+
+#if defined(_POSIX_VERSION) && _POSIX_VERSION >= 200809L
+  tmp = realpath(req->path, NULL);
+  if (tmp == NULL)
+    return -1;
+  buf = uv__strdup(tmp);
+  free(tmp); /* _Not_ uv__free. */
+  if (buf == NULL) {
+    errno = ENOMEM;
+    return -1;
+  }
+#else
+  ssize_t len;
+
+  (void)tmp;
+
+  len = uv__fs_pathmax_size(req->path);
+  buf = uv__malloc(len + 1);
+
+  if (buf == NULL) {
+    errno = ENOMEM;
+    return -1;
+  }
+
+  if (realpath(req->path, buf) == NULL) {
+    uv__free(buf);
+    return -1;
+  }
+#endif
+
+  req->ptr = buf;
+
+  return 0;
+}
+
+static ssize_t uv__fs_sendfile_emul(uv_fs_t* req) {
+  struct pollfd pfd;
+  int use_pread;
+  off_t offset;
+  ssize_t nsent;
+  ssize_t nread;
+  ssize_t nwritten;
+  size_t buflen;
+  size_t len;
+  ssize_t n;
+  int in_fd;
+  int out_fd;
+  char buf[8192];
+
+  len = req->bufsml[0].len;
+  in_fd = req->flags;
+  out_fd = req->file;
+  offset = req->off;
+  use_pread = 1;
+
+  /* Here are the rules regarding errors:
+   *
+   * 1. Read errors are reported only if nsent==0, otherwise we return nsent.
+   *    The user needs to know that some data has already been sent, to stop
+   *    them from sending it twice.
+   *
+   * 2. Write errors are always reported. Write errors are bad because they
+   *    mean data loss: we've read data but now we can't write it out.
+   *
+   * We try to use pread() and fall back to regular read() if the source fd
+   * doesn't support positional reads, for example when it's a pipe fd.
+   *
+   * If we get EAGAIN when writing to the target fd, we poll() on it until
+   * it becomes writable again.
+   *
+   * FIXME: If we get a write error when use_pread==1, it should be safe to
+   *        return the number of sent bytes instead of an error because pread()
+   *        is, in theory, idempotent. However, special files in /dev or /proc
+   *        may support pread() but not necessarily return the same data on
+   *        successive reads.
+   *
+   * FIXME: There is no way now to signal that we managed to send *some* data
+   *        before a write error.
+   */
+  for (nsent = 0; (size_t) nsent < len; ) {
+    buflen = len - nsent;
+
+    if (buflen > sizeof(buf))
+      buflen = sizeof(buf);
+
+    do
+      if (use_pread)
+        nread = pread(in_fd, buf, buflen, offset);
+      else
+        nread = read(in_fd, buf, buflen);
+    while (nread == -1 && errno == EINTR);
+
+    if (nread == 0)
+      goto out;
+
+    if (nread == -1) {
+      if (use_pread && nsent == 0 && (errno == EIO || errno == ESPIPE)) {
+        use_pread = 0;
+        continue;
+      }
+
+      if (nsent == 0)
+        nsent = -1;
+
+      goto out;
+    }
+
+    for (nwritten = 0; nwritten < nread; ) {
+      do
+        n = write(out_fd, buf + nwritten, nread - nwritten);
+      while (n == -1 && errno == EINTR);
+
+      if (n != -1) {
+        nwritten += n;
+        continue;
+      }
+
+      if (errno != EAGAIN && errno != EWOULDBLOCK) {
+        nsent = -1;
+        goto out;
+      }
+
+      pfd.fd = out_fd;
+      pfd.events = POLLOUT;
+      pfd.revents = 0;
+
+      do
+        n = poll(&pfd, 1, -1);
+      while (n == -1 && errno == EINTR);
+
+      if (n == -1 || (pfd.revents & ~POLLOUT) != 0) {
+        errno = EIO;
+        nsent = -1;
+        goto out;
+      }
+    }
+
+    offset += nread;
+    nsent += nread;
+  }
+
+out:
+  if (nsent != -1)
+    req->off = offset;
+
+  return nsent;
+}
+
+
+#ifdef __linux__
+/* Pre-4.20 kernels have a bug where CephFS uses the RADOS copy-from command
+ * in copy_file_range() when it shouldn't. There is no workaround except to
+ * fall back to a regular copy.
+ */
+static int uv__is_buggy_cephfs(int fd) {
+  struct statfs s;
+
+  if (-1 == fstatfs(fd, &s))
+    return 0;
+
+  if (s.f_type != /* CephFS */ 0xC36400)
+    return 0;
+
+  return uv__kernel_version() < /* 4.20.0 */ 0x041400;
+}
+
+
+static int uv__is_cifs_or_smb(int fd) {
+  struct statfs s;
+
+  if (-1 == fstatfs(fd, &s))
+    return 0;
+
+  switch ((unsigned) s.f_type) {
+  case 0x0000517Bu:  /* SMB */
+  case 0xFE534D42u:  /* SMB2 */
+  case 0xFF534D42u:  /* CIFS */
+    return 1;
+  }
+
+  return 0;
+}
+
+
+static ssize_t uv__fs_try_copy_file_range(int in_fd, off_t* off,
+                                          int out_fd, size_t len) {
+  static _Atomic int no_copy_file_range_support;
+  ssize_t r;
+
+  if (atomic_load_explicit(&no_copy_file_range_support, memory_order_relaxed)) {
+    errno = ENOSYS;
+    return -1;
+  }
+
+  r = uv__fs_copy_file_range(in_fd, off, out_fd, NULL, len, 0);
+
+  if (r != -1)
+    return r;
+
+  switch (errno) {
+  case EACCES:
+    /* Pre-4.20 kernels have a bug where CephFS uses the RADOS
+     * copy-from command when it shouldn't.
+     */
+    if (uv__is_buggy_cephfs(in_fd))
+      errno = ENOSYS;  /* Use fallback. */
+    break;
+  case ENOSYS:
+    atomic_store_explicit(&no_copy_file_range_support, 1, memory_order_relaxed);
+    break;
+  case EPERM:
+    /* It's been reported that CIFS spuriously fails.
+     * Consider it a transient error.
+     */
+    if (uv__is_cifs_or_smb(out_fd))
+      errno = ENOSYS;  /* Use fallback. */
+    break;
+  case ENOTSUP:
+  case EXDEV:
+    /* ENOTSUP - it could work on another file system type.
+     * EXDEV - it will not work when in_fd and out_fd are not on the same
+     *         mounted filesystem (pre Linux 5.3)
+     */
+    errno = ENOSYS;  /* Use fallback. */
+    break;
+  }
+
+  return -1;
+}
+
+#endif  /* __linux__ */
+
+
+static ssize_t uv__fs_sendfile(uv_fs_t* req) {
+  int in_fd;
+  int out_fd;
+
+  in_fd = req->flags;
+  out_fd = req->file;
+
+#if defined(__linux__) || defined(__sun)
+  {
+    off_t off;
+    ssize_t r;
+    size_t len;
+    int try_sendfile;
+
+    off = req->off;
+    len = req->bufsml[0].len;
+    try_sendfile = 1;
+
+#ifdef __linux__
+    r = uv__fs_try_copy_file_range(in_fd, &off, out_fd, len);
+    try_sendfile = (r == -1 && errno == ENOSYS);
+#endif
+
+    if (try_sendfile)
+      r = sendfile(out_fd, in_fd, &off, len);
+
+    /* sendfile() on SunOS returns EINVAL if the target fd is not a socket but
+     * it still writes out data. Fortunately, we can detect it by checking if
+     * the offset has been updated.
+     */
+    if (r != -1 || off > req->off) {
+      r = off - req->off;
+      req->off = off;
+      return r;
+    }
+
+    if (errno == EINVAL ||
+        errno == EIO ||
+        errno == ENOTSOCK ||
+        errno == EXDEV) {
+      errno = 0;
+      return uv__fs_sendfile_emul(req);
+    }
+
+    return -1;
+  }
+/* sendfile() on iOS(arm64) will throw SIGSYS signal cause crash. */
+#elif (defined(__APPLE__) && !TARGET_OS_IPHONE)                               \
+    || defined(__DragonFly__)                                                 \
+    || defined(__FreeBSD__)
+  {
+    off_t len;
+    ssize_t r;
+
+    /* sendfile() on FreeBSD and Darwin returns EAGAIN if the target fd is in
+     * non-blocking mode and not all data could be written. If a non-zero
+     * number of bytes have been sent, we don't consider it an error.
+     */
+
+#if defined(__FreeBSD__) || defined(__DragonFly__)
+#if defined(__FreeBSD__)
+    off_t off;
+
+    off = req->off;
+    r = uv__fs_copy_file_range(in_fd, &off, out_fd, NULL, req->bufsml[0].len, 0);
+    if (r >= 0) {
+        r = off - req->off;
+        req->off = off;
+        return r;
+    }
+#endif
+    len = 0;
+    r = sendfile(in_fd, out_fd, req->off, req->bufsml[0].len, NULL, &len, 0);
+#else
+    /* The darwin sendfile takes len as an input for the length to send,
+     * so make sure to initialize it with the caller's value. */
+    len = req->bufsml[0].len;
+    r = sendfile(in_fd, out_fd, req->off, &len, NULL, 0);
+#endif
+
+     /*
+     * The man page for sendfile(2) on DragonFly states that `len` contains
+     * a meaningful value ONLY in case of EAGAIN and EINTR.
+     * Nothing is said about it's value in case of other errors, so better
+     * not depend on the potential wrong assumption that is was not modified
+     * by the syscall.
+     */
+    if (r == 0 || ((errno == EAGAIN || errno == EINTR) && len != 0)) {
+      req->off += len;
+      return (ssize_t) len;
+    }
+
+    if (errno == EINVAL ||
+        errno == EIO ||
+        errno == ENOTSOCK ||
+        errno == EXDEV) {
+      errno = 0;
+      return uv__fs_sendfile_emul(req);
+    }
+
+    return -1;
+  }
+#else
+  /* Squelch compiler warnings. */
+  (void) &in_fd;
+  (void) &out_fd;
+
+  return uv__fs_sendfile_emul(req);
+#endif
+}
+
+
+static ssize_t uv__fs_utime(uv_fs_t* req) {
+#if defined(__APPLE__)                                                        \
+    || defined(_AIX71)                                                        \
+    || defined(__DragonFly__)                                                 \
+    || defined(__FreeBSD__)                                                   \
+    || defined(__HAIKU__)                                                     \
+    || defined(__NetBSD__)                                                    \
+    || defined(__OpenBSD__)                                                   \
+    || defined(__linux__)                                                     \
+    || defined(__sun)
+  struct timespec ts[2];
+  ts[0] = uv__fs_to_timespec(req->atime);
+  ts[1] = uv__fs_to_timespec(req->mtime);
+  return utimensat(AT_FDCWD, req->path, ts, 0);
+#elif defined(_AIX) && !defined(_AIX71)
+  struct utimbuf buf;
+  buf.actime = req->atime;
+  buf.modtime = req->mtime;
+  return utime(req->path, &buf);
+#elif defined(__MVS__)
+  attrib_t atr;
+  memset(&atr, 0, sizeof(atr));
+  atr.att_mtimechg = 1;
+  atr.att_atimechg = 1;
+  atr.att_mtime = req->mtime;
+  atr.att_atime = req->atime;
+  return __lchattr((char*) req->path, &atr, sizeof(atr));
+#else
+  errno = ENOSYS;
+  return -1;
+#endif
+}
+
+
+static ssize_t uv__fs_lutime(uv_fs_t* req) {
+#if defined(__APPLE__)                                                        \
+    || defined(_AIX71)                                                        \
+    || defined(__DragonFly__)                                                 \
+    || defined(__FreeBSD__)                                                   \
+    || defined(__HAIKU__)                                                     \
+    || defined(__NetBSD__)                                                    \
+    || defined(__OpenBSD__)                                                   \
+    || defined(__linux__)                                                     \
+    || defined(__sun)
+  struct timespec ts[2];
+  ts[0] = uv__fs_to_timespec(req->atime);
+  ts[1] = uv__fs_to_timespec(req->mtime);
+  return utimensat(AT_FDCWD, req->path, ts, AT_SYMLINK_NOFOLLOW);
+#else
+  errno = ENOSYS;
+  return -1;
+#endif
+}
+
+
+static ssize_t uv__fs_write(uv_fs_t* req) {
+  const struct iovec* bufs;
+  size_t nbufs;
+  ssize_t r;
+  off_t off;
+  int fd;
+
+  fd = req->file;
+  off = req->off;
+  bufs = (const struct iovec*) req->bufs;
+  nbufs = req->nbufs;
+
+  r = 0;
+  if (off < 0) {
+    if (nbufs == 1)
+      r = write(fd, bufs->iov_base, bufs->iov_len);
+    else if (nbufs > 1)
+      r = writev(fd, bufs, nbufs);
+  } else {
+    if (nbufs == 1)
+      r = pwrite(fd, bufs->iov_base, bufs->iov_len, off);
+    else if (nbufs > 1)
+      r = uv__pwritev(fd, bufs, nbufs, off);
+  }
+
+  return r;
+}
+
+
+static ssize_t uv__fs_copyfile(uv_fs_t* req) {
+  uv_fs_t fs_req;
+  uv_file srcfd;
+  uv_file dstfd;
+  struct stat src_statsbuf;
+  struct stat dst_statsbuf;
+  struct timespec times[2];
+  int dst_flags;
+  int result;
+  int err;
+  off_t bytes_to_send;
+  off_t in_offset;
+  off_t bytes_written;
+  size_t bytes_chunk;
+
+  dstfd = -1;
+  err = 0;
+
+  /* Open the source file. */
+  srcfd = uv_fs_open(NULL, &fs_req, req->path, O_RDONLY, 0, NULL);
+  uv_fs_req_cleanup(&fs_req);
+
+  if (srcfd < 0)
+    return srcfd;
+
+  /* Get the source file's mode. */
+  if (uv__fstat(srcfd, &src_statsbuf)) {
+    err = UV__ERR(errno);
+    goto out;
+  }
+
+  dst_flags = O_WRONLY | O_CREAT;
+
+  if (req->flags & UV_FS_COPYFILE_EXCL)
+    dst_flags |= O_EXCL;
+
+  /* Open the destination file. */
+  dstfd = uv_fs_open(NULL,
+                     &fs_req,
+                     req->new_path,
+                     dst_flags,
+                     src_statsbuf.st_mode,
+                     NULL);
+  uv_fs_req_cleanup(&fs_req);
+
+  if (dstfd < 0) {
+    err = dstfd;
+    goto out;
+  }
+
+  /* If the file is not being opened exclusively, verify that the source and
+     destination are not the same file. If they are the same, bail out early. */
+  if ((req->flags & UV_FS_COPYFILE_EXCL) == 0) {
+    /* Get the destination file's mode. */
+    if (uv__fstat(dstfd, &dst_statsbuf)) {
+      err = UV__ERR(errno);
+      goto out;
+    }
+
+    /* Check if srcfd and dstfd refer to the same file */
+    if (src_statsbuf.st_dev == dst_statsbuf.st_dev &&
+        src_statsbuf.st_ino == dst_statsbuf.st_ino) {
+      goto out;
+    }
+
+    /* Truncate the file in case the destination already existed. */
+    if (ftruncate(dstfd, 0) != 0) {
+      err = UV__ERR(errno);
+
+      /* ftruncate() on ceph-fuse fails with EACCES when the file is created
+       * with read only permissions. Since ftruncate() on a newly created
+       * file is a meaningless operation anyway, detect that condition
+       * and squelch the error.
+       */
+      if (err != UV_EACCES)
+        goto out;
+
+      if (dst_statsbuf.st_size > 0)
+        goto out;
+
+      err = 0;
+    }
+  }
+
+  /**
+   * Change the timestamps of the destination file to match the source file.
+   */
+#if defined(__APPLE__)
+  times[0] = src_statsbuf.st_atimespec;
+  times[1] = src_statsbuf.st_mtimespec;
+#elif defined(_AIX)
+  times[0].tv_sec = src_statsbuf.st_atime;
+  times[0].tv_nsec = src_statsbuf.st_atime_n;
+  times[1].tv_sec = src_statsbuf.st_mtime;
+  times[1].tv_nsec = src_statsbuf.st_mtime_n;
+#else
+  times[0] = src_statsbuf.st_atim;
+  times[1] = src_statsbuf.st_mtim;
+#endif
+
+  if (futimens(dstfd, times) == -1) {
+    err = UV__ERR(errno);
+    goto out;
+  }
+
+  /*
+   * Change the ownership and permissions of the destination file to match the
+   * source file.
+   * `cp -p` does not care about errors here, so we don't either. Reuse the
+   * `result` variable to silence a -Wunused-result warning.
+   */
+  result = fchown(dstfd, src_statsbuf.st_uid, src_statsbuf.st_gid);
+
+  if (fchmod(dstfd, src_statsbuf.st_mode) == -1) {
+    err = UV__ERR(errno);
+#ifdef __linux__
+    /* fchmod() on CIFS shares always fails with EPERM unless the share is
+     * mounted with "noperm". As fchmod() is a meaningless operation on such
+     * shares anyway, detect that condition and squelch the error.
+     */
+    if (err != UV_EPERM)
+      goto out;
+
+    if (!uv__is_cifs_or_smb(dstfd))
+      goto out;
+
+    err = 0;
+#else  /* !__linux__ */
+    goto out;
+#endif  /* !__linux__ */
+  }
+
+#ifdef FICLONE
+  if (req->flags & UV_FS_COPYFILE_FICLONE ||
+      req->flags & UV_FS_COPYFILE_FICLONE_FORCE) {
+    if (ioctl(dstfd, FICLONE, srcfd) == 0) {
+      /* ioctl() with FICLONE succeeded. */
+      goto out;
+    }
+    /* If an error occurred and force was set, return the error to the caller;
+     * fall back to sendfile() when force was not set. */
+    if (req->flags & UV_FS_COPYFILE_FICLONE_FORCE) {
+      err = UV__ERR(errno);
+      goto out;
+    }
+  }
+#else
+  if (req->flags & UV_FS_COPYFILE_FICLONE_FORCE) {
+    err = UV_ENOSYS;
+    goto out;
+  }
+#endif
+
+  bytes_to_send = src_statsbuf.st_size;
+  in_offset = 0;
+  while (bytes_to_send != 0) {
+    bytes_chunk = SSIZE_MAX;
+    if (bytes_to_send < (off_t) bytes_chunk)
+      bytes_chunk = bytes_to_send;
+    uv_fs_sendfile(NULL, &fs_req, dstfd, srcfd, in_offset, bytes_chunk, NULL);
+    bytes_written = fs_req.result;
+    uv_fs_req_cleanup(&fs_req);
+
+    if (bytes_written < 0) {
+      err = bytes_written;
+      break;
+    }
+
+    bytes_to_send -= bytes_written;
+    in_offset += bytes_written;
+  }
+
+out:
+  if (err < 0)
+    result = err;
+  else
+    result = 0;
+
+  /* Close the source file. */
+  err = uv__close_nocheckstdio(srcfd);
+
+  /* Don't overwrite any existing errors. */
+  if (err != 0 && result == 0)
+    result = err;
+
+  /* Close the destination file if it is open. */
+  if (dstfd >= 0) {
+    err = uv__close_nocheckstdio(dstfd);
+
+    /* Don't overwrite any existing errors. */
+    if (err != 0 && result == 0)
+      result = err;
+
+    /* Remove the destination file if something went wrong. */
+    if (result != 0) {
+      uv_fs_unlink(NULL, &fs_req, req->new_path, NULL);
+      /* Ignore the unlink return value, as an error already happened. */
+      uv_fs_req_cleanup(&fs_req);
+    }
+  }
+
+  if (result == 0)
+    return 0;
+
+  errno = UV__ERR(result);
+  return -1;
+}
+
+static void uv__to_stat(struct stat* src, uv_stat_t* dst) {
+  dst->st_dev = src->st_dev;
+  dst->st_mode = src->st_mode;
+  dst->st_nlink = src->st_nlink;
+  dst->st_uid = src->st_uid;
+  dst->st_gid = src->st_gid;
+  dst->st_rdev = src->st_rdev;
+  dst->st_ino = src->st_ino;
+  dst->st_size = src->st_size;
+  dst->st_blksize = src->st_blksize;
+  dst->st_blocks = src->st_blocks;
+
+#if defined(__APPLE__)
+  dst->st_atim.tv_sec = src->st_atimespec.tv_sec;
+  dst->st_atim.tv_nsec = src->st_atimespec.tv_nsec;
+  dst->st_mtim.tv_sec = src->st_mtimespec.tv_sec;
+  dst->st_mtim.tv_nsec = src->st_mtimespec.tv_nsec;
+  dst->st_ctim.tv_sec = src->st_ctimespec.tv_sec;
+  dst->st_ctim.tv_nsec = src->st_ctimespec.tv_nsec;
+  dst->st_birthtim.tv_sec = src->st_birthtimespec.tv_sec;
+  dst->st_birthtim.tv_nsec = src->st_birthtimespec.tv_nsec;
+  dst->st_flags = src->st_flags;
+  dst->st_gen = src->st_gen;
+#elif defined(__ANDROID__)
+  dst->st_atim.tv_sec = src->st_atime;
+  dst->st_atim.tv_nsec = src->st_atimensec;
+  dst->st_mtim.tv_sec = src->st_mtime;
+  dst->st_mtim.tv_nsec = src->st_mtimensec;
+  dst->st_ctim.tv_sec = src->st_ctime;
+  dst->st_ctim.tv_nsec = src->st_ctimensec;
+  dst->st_birthtim.tv_sec = src->st_ctime;
+  dst->st_birthtim.tv_nsec = src->st_ctimensec;
+  dst->st_flags = 0;
+  dst->st_gen = 0;
+#elif !defined(_AIX) &&         \
+    !defined(__MVS__) && (      \
+    defined(__DragonFly__)   || \
+    defined(__FreeBSD__)     || \
+    defined(__OpenBSD__)     || \
+    defined(__NetBSD__)      || \
+    defined(_GNU_SOURCE)     || \
+    defined(_BSD_SOURCE)     || \
+    defined(_SVID_SOURCE)    || \
+    defined(_XOPEN_SOURCE)   || \
+    defined(_DEFAULT_SOURCE))
+  dst->st_atim.tv_sec = src->st_atim.tv_sec;
+  dst->st_atim.tv_nsec = src->st_atim.tv_nsec;
+  dst->st_mtim.tv_sec = src->st_mtim.tv_sec;
+  dst->st_mtim.tv_nsec = src->st_mtim.tv_nsec;
+  dst->st_ctim.tv_sec = src->st_ctim.tv_sec;
+  dst->st_ctim.tv_nsec = src->st_ctim.tv_nsec;
+# if defined(__FreeBSD__)    || \
+     defined(__NetBSD__)
+  dst->st_birthtim.tv_sec = src->st_birthtim.tv_sec;
+  dst->st_birthtim.tv_nsec = src->st_birthtim.tv_nsec;
+  dst->st_flags = src->st_flags;
+  dst->st_gen = src->st_gen;
+# else
+  dst->st_birthtim.tv_sec = src->st_ctim.tv_sec;
+  dst->st_birthtim.tv_nsec = src->st_ctim.tv_nsec;
+  dst->st_flags = 0;
+  dst->st_gen = 0;
+# endif
+#else
+  dst->st_atim.tv_sec = src->st_atime;
+  dst->st_atim.tv_nsec = 0;
+  dst->st_mtim.tv_sec = src->st_mtime;
+  dst->st_mtim.tv_nsec = 0;
+  dst->st_ctim.tv_sec = src->st_ctime;
+  dst->st_ctim.tv_nsec = 0;
+  dst->st_birthtim.tv_sec = src->st_ctime;
+  dst->st_birthtim.tv_nsec = 0;
+  dst->st_flags = 0;
+  dst->st_gen = 0;
+#endif
+}
+
+
+static int uv__fs_statx(int fd,
+                        const char* path,
+                        int is_fstat,
+                        int is_lstat,
+                        uv_stat_t* buf) {
+  STATIC_ASSERT(UV_ENOSYS != -1);
+#ifdef __linux__
+  static _Atomic int no_statx;
+  struct uv__statx statxbuf;
+  int dirfd;
+  int flags;
+  int mode;
+  int rc;
+
+  if (atomic_load_explicit(&no_statx, memory_order_relaxed))
+    return UV_ENOSYS;
+
+  dirfd = AT_FDCWD;
+  flags = 0; /* AT_STATX_SYNC_AS_STAT */
+  mode = 0xFFF; /* STATX_BASIC_STATS + STATX_BTIME */
+
+  if (is_fstat) {
+    dirfd = fd;
+    flags |= 0x1000; /* AT_EMPTY_PATH */
+  }
+
+  if (is_lstat)
+    flags |= AT_SYMLINK_NOFOLLOW;
+
+  rc = uv__statx(dirfd, path, flags, mode, &statxbuf);
+
+  switch (rc) {
+  case 0:
+    break;
+  case -1:
+    /* EPERM happens when a seccomp filter rejects the system call.
+     * Has been observed with libseccomp < 2.3.3 and docker < 18.04.
+     * EOPNOTSUPP is used on DVS exported filesystems
+     */
+    if (errno != EINVAL && errno != EPERM && errno != ENOSYS && errno != EOPNOTSUPP)
+      return -1;
+    /* Fall through. */
+  default:
+    /* Normally on success, zero is returned and On error, -1 is returned.
+     * Observed on S390 RHEL running in a docker container with statx not
+     * implemented, rc might return 1 with 0 set as the error code in which
+     * case we return ENOSYS.
+     */
+    atomic_store_explicit(&no_statx, 1, memory_order_relaxed);
+    return UV_ENOSYS;
+  }
+
+  uv__statx_to_stat(&statxbuf, buf);
+
+  return 0;
+#else
+  return UV_ENOSYS;
+#endif /* __linux__ */
+}
+
+
+static int uv__fs_stat(const char *path, uv_stat_t *buf) {
+  struct stat pbuf;
+  int ret;
+
+  ret = uv__fs_statx(-1, path, /* is_fstat */ 0, /* is_lstat */ 0, buf);
+  if (ret != UV_ENOSYS)
+    return ret;
+
+  ret = uv__stat(path, &pbuf);
+  if (ret == 0)
+    uv__to_stat(&pbuf, buf);
+
+  return ret;
+}
+
+
+static int uv__fs_lstat(const char *path, uv_stat_t *buf) {
+  struct stat pbuf;
+  int ret;
+
+  ret = uv__fs_statx(-1, path, /* is_fstat */ 0, /* is_lstat */ 1, buf);
+  if (ret != UV_ENOSYS)
+    return ret;
+
+  ret = uv__lstat(path, &pbuf);
+  if (ret == 0)
+    uv__to_stat(&pbuf, buf);
+
+  return ret;
+}
+
+
+static int uv__fs_fstat(int fd, uv_stat_t *buf) {
+  struct stat pbuf;
+  int ret;
+
+  ret = uv__fs_statx(fd, "", /* is_fstat */ 1, /* is_lstat */ 0, buf);
+  if (ret != UV_ENOSYS)
+    return ret;
+
+  ret = uv__fstat(fd, &pbuf);
+  if (ret == 0)
+    uv__to_stat(&pbuf, buf);
+
+  return ret;
+}
+
+static size_t uv__fs_buf_offset(uv_buf_t* bufs, size_t size) {
+  size_t offset;
+  /* Figure out which bufs are done */
+  for (offset = 0; size > 0 && bufs[offset].len <= size; ++offset)
+    size -= bufs[offset].len;
+
+  /* Fix a partial read/write */
+  if (size > 0) {
+    bufs[offset].base += size;
+    bufs[offset].len -= size;
+  }
+  return offset;
+}
+
+static ssize_t uv__fs_write_all(uv_fs_t* req) {
+  unsigned int iovmax;
+  unsigned int nbufs;
+  uv_buf_t* bufs;
+  ssize_t total;
+  ssize_t result;
+
+  iovmax = uv__getiovmax();
+  nbufs = req->nbufs;
+  bufs = req->bufs;
+  total = 0;
+
+  while (nbufs > 0) {
+    req->nbufs = nbufs;
+    if (req->nbufs > iovmax)
+      req->nbufs = iovmax;
+
+    do
+      result = uv__fs_write(req);
+    while (result < 0 && errno == EINTR);
+
+    if (result <= 0) {
+      if (total == 0)
+        total = result;
+      break;
+    }
+
+    if (req->off >= 0)
+      req->off += result;
+
+    req->nbufs = uv__fs_buf_offset(req->bufs, result);
+    req->bufs += req->nbufs;
+    nbufs -= req->nbufs;
+    total += result;
+  }
+
+  if (bufs != req->bufsml)
+    uv__free(bufs);
+
+  req->bufs = NULL;
+  req->nbufs = 0;
+
+  return total;
+}
+
+
+static void uv__fs_work(struct uv__work* w) {
+  int retry_on_eintr;
+  uv_fs_t* req;
+  ssize_t r;
+
+  req = container_of(w, uv_fs_t, work_req);
+  retry_on_eintr = !(req->fs_type == UV_FS_CLOSE ||
+                     req->fs_type == UV_FS_READ);
+
+  do {
+    errno = 0;
+
+#define X(type, action)                                                       \
+  case UV_FS_ ## type:                                                        \
+    r = action;                                                               \
+    break;
+
+    switch (req->fs_type) {
+    X(ACCESS, access(req->path, req->flags));
+    X(CHMOD, chmod(req->path, req->mode));
+    X(CHOWN, chown(req->path, req->uid, req->gid));
+    X(CLOSE, uv__fs_close(req->file));
+    X(COPYFILE, uv__fs_copyfile(req));
+    X(FCHMOD, fchmod(req->file, req->mode));
+    X(FCHOWN, fchown(req->file, req->uid, req->gid));
+    X(LCHOWN, lchown(req->path, req->uid, req->gid));
+    X(FDATASYNC, uv__fs_fdatasync(req));
+    X(FSTAT, uv__fs_fstat(req->file, &req->statbuf));
+    X(FSYNC, uv__fs_fsync(req));
+    X(FTRUNCATE, ftruncate(req->file, req->off));
+    X(FUTIME, uv__fs_futime(req));
+    X(LUTIME, uv__fs_lutime(req));
+    X(LSTAT, uv__fs_lstat(req->path, &req->statbuf));
+    X(LINK, link(req->path, req->new_path));
+    X(MKDIR, mkdir(req->path, req->mode));
+    X(MKDTEMP, uv__fs_mkdtemp(req));
+    X(MKSTEMP, uv__fs_mkstemp(req));
+    X(OPEN, uv__fs_open(req));
+    X(READ, uv__fs_read(req));
+    X(SCANDIR, uv__fs_scandir(req));
+    X(OPENDIR, uv__fs_opendir(req));
+    X(READDIR, uv__fs_readdir(req));
+    X(CLOSEDIR, uv__fs_closedir(req));
+    X(READLINK, uv__fs_readlink(req));
+    X(REALPATH, uv__fs_realpath(req));
+    X(RENAME, rename(req->path, req->new_path));
+    X(RMDIR, rmdir(req->path));
+    X(SENDFILE, uv__fs_sendfile(req));
+    X(STAT, uv__fs_stat(req->path, &req->statbuf));
+    X(STATFS, uv__fs_statfs(req));
+    X(SYMLINK, symlink(req->path, req->new_path));
+    X(UNLINK, unlink(req->path));
+    X(UTIME, uv__fs_utime(req));
+    X(WRITE, uv__fs_write_all(req));
+    default: abort();
+    }
+#undef X
+  } while (r == -1 && errno == EINTR && retry_on_eintr);
+
+  if (r == -1)
+    req->result = UV__ERR(errno);
+  else
+    req->result = r;
+
+  if (r == 0 && (req->fs_type == UV_FS_STAT ||
+                 req->fs_type == UV_FS_FSTAT ||
+                 req->fs_type == UV_FS_LSTAT)) {
+    req->ptr = &req->statbuf;
+  }
+}
+
+
+static void uv__fs_done(struct uv__work* w, int status) {
+  uv_fs_t* req;
+
+  req = container_of(w, uv_fs_t, work_req);
+  uv__req_unregister(req->loop);
+
+  if (status == UV_ECANCELED) {
+    assert(req->result == 0);
+    req->result = UV_ECANCELED;
+  }
+
+  req->cb(req);
+}
+
+
+void uv__fs_post(uv_loop_t* loop, uv_fs_t* req) {
+  uv__req_register(loop);
+  uv__work_submit(loop,
+                  &req->work_req,
+                  UV__WORK_FAST_IO,
+                  uv__fs_work,
+                  uv__fs_done);
+}
+
+
+int uv_fs_access(uv_loop_t* loop,
+                 uv_fs_t* req,
+                 const char* path,
+                 int flags,
+                 uv_fs_cb cb) {
+  INIT(ACCESS);
+  PATH;
+  req->flags = flags;
+  POST;
+}
+
+
+int uv_fs_chmod(uv_loop_t* loop,
+                uv_fs_t* req,
+                const char* path,
+                int mode,
+                uv_fs_cb cb) {
+  INIT(CHMOD);
+  PATH;
+  req->mode = mode;
+  POST;
+}
+
+
+int uv_fs_chown(uv_loop_t* loop,
+                uv_fs_t* req,
+                const char* path,
+                uv_uid_t uid,
+                uv_gid_t gid,
+                uv_fs_cb cb) {
+  INIT(CHOWN);
+  PATH;
+  req->uid = uid;
+  req->gid = gid;
+  POST;
+}
+
+
+int uv_fs_close(uv_loop_t* loop, uv_fs_t* req, uv_file file, uv_fs_cb cb) {
+  INIT(CLOSE);
+  req->file = file;
+  if (cb != NULL)
+    if (uv__iou_fs_close(loop, req))
+      return 0;
+  POST;
+}
+
+
+int uv_fs_fchmod(uv_loop_t* loop,
+                 uv_fs_t* req,
+                 uv_file file,
+                 int mode,
+                 uv_fs_cb cb) {
+  INIT(FCHMOD);
+  req->file = file;
+  req->mode = mode;
+  POST;
+}
+
+
+int uv_fs_fchown(uv_loop_t* loop,
+                 uv_fs_t* req,
+                 uv_file file,
+                 uv_uid_t uid,
+                 uv_gid_t gid,
+                 uv_fs_cb cb) {
+  INIT(FCHOWN);
+  req->file = file;
+  req->uid = uid;
+  req->gid = gid;
+  POST;
+}
+
+
+int uv_fs_lchown(uv_loop_t* loop,
+                 uv_fs_t* req,
+                 const char* path,
+                 uv_uid_t uid,
+                 uv_gid_t gid,
+                 uv_fs_cb cb) {
+  INIT(LCHOWN);
+  PATH;
+  req->uid = uid;
+  req->gid = gid;
+  POST;
+}
+
+
+int uv_fs_fdatasync(uv_loop_t* loop, uv_fs_t* req, uv_file file, uv_fs_cb cb) {
+  INIT(FDATASYNC);
+  req->file = file;
+  if (cb != NULL)
+    if (uv__iou_fs_fsync_or_fdatasync(loop, req, /* IORING_FSYNC_DATASYNC */ 1))
+      return 0;
+  POST;
+}
+
+
+int uv_fs_fstat(uv_loop_t* loop, uv_fs_t* req, uv_file file, uv_fs_cb cb) {
+  INIT(FSTAT);
+  req->file = file;
+  if (cb != NULL)
+    if (uv__iou_fs_statx(loop, req, /* is_fstat */ 1, /* is_lstat */ 0))
+      return 0;
+  POST;
+}
+
+
+int uv_fs_fsync(uv_loop_t* loop, uv_fs_t* req, uv_file file, uv_fs_cb cb) {
+  INIT(FSYNC);
+  req->file = file;
+  if (cb != NULL)
+    if (uv__iou_fs_fsync_or_fdatasync(loop, req, /* no flags */ 0))
+      return 0;
+  POST;
+}
+
+
+int uv_fs_ftruncate(uv_loop_t* loop,
+                    uv_fs_t* req,
+                    uv_file file,
+                    int64_t off,
+                    uv_fs_cb cb) {
+  INIT(FTRUNCATE);
+  req->file = file;
+  req->off = off;
+  if (cb != NULL)
+    if (uv__iou_fs_ftruncate(loop, req))
+      return 0;
+  POST;
+}
+
+
+int uv_fs_futime(uv_loop_t* loop,
+                 uv_fs_t* req,
+                 uv_file file,
+                 double atime,
+                 double mtime,
+                 uv_fs_cb cb) {
+  INIT(FUTIME);
+  req->file = file;
+  req->atime = atime;
+  req->mtime = mtime;
+  POST;
+}
+
+int uv_fs_lutime(uv_loop_t* loop,
+                 uv_fs_t* req,
+                 const char* path,
+                 double atime,
+                 double mtime,
+                 uv_fs_cb cb) {
+  INIT(LUTIME);
+  PATH;
+  req->atime = atime;
+  req->mtime = mtime;
+  POST;
+}
+
+
+int uv_fs_lstat(uv_loop_t* loop, uv_fs_t* req, const char* path, uv_fs_cb cb) {
+  INIT(LSTAT);
+  PATH;
+  if (cb != NULL)
+    if (uv__iou_fs_statx(loop, req, /* is_fstat */ 0, /* is_lstat */ 1))
+      return 0;
+  POST;
+}
+
+
+int uv_fs_link(uv_loop_t* loop,
+               uv_fs_t* req,
+               const char* path,
+               const char* new_path,
+               uv_fs_cb cb) {
+  INIT(LINK);
+  PATH2;
+  if (cb != NULL)
+    if (uv__iou_fs_link(loop, req))
+      return 0;
+  POST;
+}
+
+
+int uv_fs_mkdir(uv_loop_t* loop,
+                uv_fs_t* req,
+                const char* path,
+                int mode,
+                uv_fs_cb cb) {
+  INIT(MKDIR);
+  PATH;
+  req->mode = mode;
+  if (cb != NULL)
+    if (uv__iou_fs_mkdir(loop, req))
+      return 0;
+  POST;
+}
+
+
+int uv_fs_mkdtemp(uv_loop_t* loop,
+                  uv_fs_t* req,
+                  const char* tpl,
+                  uv_fs_cb cb) {
+  INIT(MKDTEMP);
+  req->path = uv__strdup(tpl);
+  if (req->path == NULL)
+    return UV_ENOMEM;
+  POST;
+}
+
+
+int uv_fs_mkstemp(uv_loop_t* loop,
+                  uv_fs_t* req,
+                  const char* tpl,
+                  uv_fs_cb cb) {
+  INIT(MKSTEMP);
+  req->path = uv__strdup(tpl);
+  if (req->path == NULL)
+    return UV_ENOMEM;
+  POST;
+}
+
+
+int uv_fs_open(uv_loop_t* loop,
+               uv_fs_t* req,
+               const char* path,
+               int flags,
+               int mode,
+               uv_fs_cb cb) {
+  INIT(OPEN);
+  PATH;
+  req->flags = flags;
+  req->mode = mode;
+  if (cb != NULL)
+    if (uv__iou_fs_open(loop, req))
+      return 0;
+  POST;
+}
+
+
+int uv_fs_read(uv_loop_t* loop, uv_fs_t* req,
+               uv_file file,
+               const uv_buf_t bufs[],
+               unsigned int nbufs,
+               int64_t off,
+               uv_fs_cb cb) {
+  INIT(READ);
+
+  if (bufs == NULL || nbufs == 0)
+    return UV_EINVAL;
+
+  req->off = off;
+  req->file = file;
+  req->bufs = (uv_buf_t*) bufs;  /* Safe, doesn't mutate |bufs| */
+  req->nbufs = nbufs;
+
+  if (cb == NULL)
+    goto post;
+
+  req->bufs = req->bufsml;
+  if (nbufs > ARRAY_SIZE(req->bufsml))
+    req->bufs = uv__malloc(nbufs * sizeof(*bufs));
+
+  if (req->bufs == NULL)
+    return UV_ENOMEM;
+
+  memcpy(req->bufs, bufs, nbufs * sizeof(*bufs));
+
+  if (uv__iou_fs_read_or_write(loop, req, /* is_read */ 1))
+    return 0;
+
+post:
+  POST;
+}
+
+
+int uv_fs_scandir(uv_loop_t* loop,
+                  uv_fs_t* req,
+                  const char* path,
+                  int flags,
+                  uv_fs_cb cb) {
+  INIT(SCANDIR);
+  PATH;
+  req->flags = flags;
+  POST;
+}
+
+int uv_fs_opendir(uv_loop_t* loop,
+                  uv_fs_t* req,
+                  const char* path,
+                  uv_fs_cb cb) {
+  INIT(OPENDIR);
+  PATH;
+  POST;
+}
+
+int uv_fs_readdir(uv_loop_t* loop,
+                  uv_fs_t* req,
+                  uv_dir_t* dir,
+                  uv_fs_cb cb) {
+  INIT(READDIR);
+
+  if (dir == NULL || dir->dir == NULL || dir->dirents == NULL)
+    return UV_EINVAL;
+
+  req->ptr = dir;
+  POST;
+}
+
+int uv_fs_closedir(uv_loop_t* loop,
+                   uv_fs_t* req,
+                   uv_dir_t* dir,
+                   uv_fs_cb cb) {
+  INIT(CLOSEDIR);
+
+  if (dir == NULL)
+    return UV_EINVAL;
+
+  req->ptr = dir;
+  POST;
+}
+
+int uv_fs_readlink(uv_loop_t* loop,
+                   uv_fs_t* req,
+                   const char* path,
+                   uv_fs_cb cb) {
+  INIT(READLINK);
+  PATH;
+  POST;
+}
+
+
+int uv_fs_realpath(uv_loop_t* loop,
+                  uv_fs_t* req,
+                  const char * path,
+                  uv_fs_cb cb) {
+  INIT(REALPATH);
+  PATH;
+  POST;
+}
+
+
+int uv_fs_rename(uv_loop_t* loop,
+                 uv_fs_t* req,
+                 const char* path,
+                 const char* new_path,
+                 uv_fs_cb cb) {
+  INIT(RENAME);
+  PATH2;
+  if (cb != NULL)
+    if (uv__iou_fs_rename(loop, req))
+      return 0;
+  POST;
+}
+
+
+int uv_fs_rmdir(uv_loop_t* loop, uv_fs_t* req, const char* path, uv_fs_cb cb) {
+  INIT(RMDIR);
+  PATH;
+  POST;
+}
+
+
+int uv_fs_sendfile(uv_loop_t* loop,
+                   uv_fs_t* req,
+                   uv_file out_fd,
+                   uv_file in_fd,
+                   int64_t off,
+                   size_t len,
+                   uv_fs_cb cb) {
+  INIT(SENDFILE);
+  req->flags = in_fd; /* hack */
+  req->file = out_fd;
+  req->off = off;
+  req->bufsml[0].len = len;
+  POST;
+}
+
+
+int uv_fs_stat(uv_loop_t* loop, uv_fs_t* req, const char* path, uv_fs_cb cb) {
+  INIT(STAT);
+  PATH;
+  if (cb != NULL)
+    if (uv__iou_fs_statx(loop, req, /* is_fstat */ 0, /* is_lstat */ 0))
+      return 0;
+  POST;
+}
+
+
+int uv_fs_symlink(uv_loop_t* loop,
+                  uv_fs_t* req,
+                  const char* path,
+                  const char* new_path,
+                  int flags,
+                  uv_fs_cb cb) {
+  INIT(SYMLINK);
+  PATH2;
+  req->flags = flags;
+  if (cb != NULL)
+    if (uv__iou_fs_symlink(loop, req))
+      return 0;
+  POST;
+}
+
+
+int uv_fs_unlink(uv_loop_t* loop, uv_fs_t* req, const char* path, uv_fs_cb cb) {
+  INIT(UNLINK);
+  PATH;
+  if (cb != NULL)
+    if (uv__iou_fs_unlink(loop, req))
+      return 0;
+  POST;
+}
+
+
+int uv_fs_utime(uv_loop_t* loop,
+                uv_fs_t* req,
+                const char* path,
+                double atime,
+                double mtime,
+                uv_fs_cb cb) {
+  INIT(UTIME);
+  PATH;
+  req->atime = atime;
+  req->mtime = mtime;
+  POST;
+}
+
+
+int uv_fs_write(uv_loop_t* loop,
+                uv_fs_t* req,
+                uv_file file,
+                const uv_buf_t bufs[],
+                unsigned int nbufs,
+                int64_t off,
+                uv_fs_cb cb) {
+  INIT(WRITE);
+
+  if (bufs == NULL || nbufs == 0)
+    return UV_EINVAL;
+
+  req->file = file;
+
+  req->nbufs = nbufs;
+  req->bufs = req->bufsml;
+  if (nbufs > ARRAY_SIZE(req->bufsml))
+    req->bufs = uv__malloc(nbufs * sizeof(*bufs));
+
+  if (req->bufs == NULL)
+    return UV_ENOMEM;
+
+  memcpy(req->bufs, bufs, nbufs * sizeof(*bufs));
+
+  req->off = off;
+
+  if (cb != NULL)
+    if (uv__iou_fs_read_or_write(loop, req, /* is_read */ 0))
+      return 0;
+
+  POST;
+}
+
+
+void uv_fs_req_cleanup(uv_fs_t* req) {
+  if (req == NULL)
+    return;
+
+  /* Only necessary for asynchronous requests, i.e., requests with a callback.
+   * Synchronous ones don't copy their arguments and have req->path and
+   * req->new_path pointing to user-owned memory.  UV_FS_MKDTEMP and
+   * UV_FS_MKSTEMP are the exception to the rule, they always allocate memory.
+   */
+  if (req->path != NULL &&
+      (req->cb != NULL ||
+        req->fs_type == UV_FS_MKDTEMP || req->fs_type == UV_FS_MKSTEMP))
+    uv__free((void*) req->path);  /* Memory is shared with req->new_path. */
+
+  req->path = NULL;
+  req->new_path = NULL;
+
+  if (req->fs_type == UV_FS_READDIR && req->ptr != NULL)
+    uv__fs_readdir_cleanup(req);
+
+  if (req->fs_type == UV_FS_SCANDIR && req->ptr != NULL)
+    uv__fs_scandir_cleanup(req);
+
+  if (req->bufs != req->bufsml)
+    uv__free(req->bufs);
+  req->bufs = NULL;
+
+  if (req->fs_type != UV_FS_OPENDIR && req->ptr != &req->statbuf)
+    uv__free(req->ptr);
+  req->ptr = NULL;
+}
+
+
+int uv_fs_copyfile(uv_loop_t* loop,
+                   uv_fs_t* req,
+                   const char* path,
+                   const char* new_path,
+                   int flags,
+                   uv_fs_cb cb) {
+  INIT(COPYFILE);
+
+  if (flags & ~(UV_FS_COPYFILE_EXCL |
+                UV_FS_COPYFILE_FICLONE |
+                UV_FS_COPYFILE_FICLONE_FORCE)) {
+    return UV_EINVAL;
+  }
+
+  PATH2;
+  req->flags = flags;
+  POST;
+}
+
+
+int uv_fs_statfs(uv_loop_t* loop,
+                 uv_fs_t* req,
+                 const char* path,
+                 uv_fs_cb cb) {
+  INIT(STATFS);
+  PATH;
+  POST;
+}
+
+int uv_fs_get_system_error(const uv_fs_t* req) {
+  return -req->result;
+}