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- /* Copyright (c) 2003-2004, Roger Dingledine
- * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
- * Copyright (c) 2007-2018, 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;
- }
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