4 files changed, 159 insertions, 0 deletions
diff --git a/src/lib/fdio/.may_include b/src/lib/fdio/.may_include
new file mode 100644
index 0000000000..30fd277b81
--- /dev/null
+++ b/src/lib/fdio/.may_include
@@ -0,0 +1,4 @@
+orconfig.h
+lib/cc/*.h
+lib/err/*.h
+lib/fdio/*.h
diff --git a/src/lib/fdio/fdio.c b/src/lib/fdio/fdio.c
new file mode 100644
index 0000000000..6c87af791d
--- /dev/null
+++ b/src/lib/fdio/fdio.c
@@ -0,0 +1,115 @@
+/* Copyright (c) 2003-2004, Roger Dingledine
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file fdio.c
+ *
+ * \brief Low-level compatibility wrappers for fd-based IO.
+ **/
+
+#include "orconfig.h"
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#ifdef _WIN32
+#include <windows.h>
+#endif
+
+#include "lib/fdio/fdio.h"
+#include "lib/cc/torint.h"
+#include "lib/err/torerr.h"
+
+#include <stdlib.h>
+
+/** @{ */
+/** Some old versions of Unix didn't define constants for these values,
+ * and instead expect you to say 0, 1, or 2. */
+#ifndef SEEK_SET
+#define SEEK_SET 0
+#endif
+#ifndef SEEK_CUR
+#define SEEK_CUR 1
+#endif
+#ifndef SEEK_END
+#define SEEK_END 2
+#endif
+/** @} */
+
+/** Return the position of <b>fd</b> with respect to the start of the file. */
+off_t
+tor_fd_getpos(int fd)
+{
+#ifdef _WIN32
+  return (off_t) _lseek(fd, 0, SEEK_CUR);
+#else
+  return (off_t) lseek(fd, 0, SEEK_CUR);
+#endif
+}
+
+/** Move <b>fd</b> to the end of the file. Return -1 on error, 0 on success.
+ * If the file is a pipe, do nothing and succeed.
+ **/
+int
+tor_fd_seekend(int fd)
+{
+#ifdef _WIN32
+  return _lseek(fd, 0, SEEK_END) < 0 ? -1 : 0;
+#else
+  off_t rc = lseek(fd, 0, SEEK_END) < 0 ? -1 : 0;
+#ifdef ESPIPE
+  /* If we get an error and ESPIPE, then it's a pipe or a socket of a fifo:
+   * no need to worry. */
+  if (rc < 0 && errno == ESPIPE)
+    rc = 0;
+#endif /* defined(ESPIPE) */
+  return (rc < 0) ? -1 : 0;
+#endif /* defined(_WIN32) */
+}
+
+/** Move <b>fd</b> to position <b>pos</b> in the file. Return -1 on error, 0
+ * on success. */
+int
+tor_fd_setpos(int fd, off_t pos)
+{
+#ifdef _WIN32
+  return _lseek(fd, pos, SEEK_SET) < 0 ? -1 : 0;
+#else
+  return lseek(fd, pos, SEEK_SET) < 0 ? -1 : 0;
+#endif
+}
+
+/** Replacement for ftruncate(fd, 0): move to the front of the file and remove
+ * all the rest of the file. Return -1 on error, 0 on success. */
+int
+tor_ftruncate(int fd)
+{
+  /* Rumor has it that some versions of ftruncate do not move the file pointer.
+   */
+  if (tor_fd_setpos(fd, 0) < 0)
+    return -1;
+
+#ifdef _WIN32
+  return _chsize(fd, 0);
+#else
+  return ftruncate(fd, 0);
+#endif
+}
+
+/** Minimal version of write_all, for use by logging. */
+int
+write_all_to_fd_minimal(int fd, const char *buf, size_t count)
+{
+  size_t written = 0;
+  raw_assert(count < SSIZE_MAX);
+
+  while (written < count) {
+    ssize_t result = write(fd, buf+written, count-written);
+    if (result<0)
+      return -1;
+    written += result;
+  }
+  return 0;
+}
diff --git a/src/lib/fdio/fdio.h b/src/lib/fdio/fdio.h
new file mode 100644
index 0000000000..8395af353b
--- /dev/null
+++ b/src/lib/fdio/fdio.h
@@ -0,0 +1,23 @@
+/* Copyright (c) 2003-2004, Roger Dingledine
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file fdio.h
+ *
+ * \brief Header for fdio.c
+ **/
+
+#ifndef TOR_FDIO_H
+#define TOR_FDIO_H
+
+#include <stddef.h>
+
+off_t tor_fd_getpos(int fd);
+int tor_fd_setpos(int fd, off_t pos);
+int tor_fd_seekend(int fd);
+int tor_ftruncate(int fd);
+int write_all_to_fd_minimal(int fd, const char *buf, size_t count);
+
+#endif /* !defined(TOR_FDIO_H) */
diff --git a/src/lib/fdio/include.am b/src/lib/fdio/include.am
new file mode 100644
index 0000000000..6c18f00a0d
--- /dev/null
+++ b/src/lib/fdio/include.am
@@ -0,0 +1,17 @@
+
+noinst_LIBRARIES += src/lib/libtor-fdio.a
+
+if UNITTESTS_ENABLED
+noinst_LIBRARIES += src/lib/libtor-fdio-testing.a
+endif
+
+src_lib_libtor_fdio_a_SOURCES =			\
+	src/lib/fdio/fdio.c
+
+src_lib_libtor_fdio_testing_a_SOURCES = \
+	$(src_lib_libtor_fdio_a_SOURCES)
+src_lib_libtor_fdio_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
+src_lib_libtor_fdio_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
+
+noinst_HEADERS +=					\
+	src/lib/fdio/fdio.h