libc-bottom-half/cloudlibc/src/libc/unistd/lseek.c

   1 // Copyright (c) 2015-2016 Nuxi, https://nuxi.nl/
   2 //
   3 // SPDX-License-Identifier: BSD-2-Clause
   4
   5 #include <assert.h>
   6 #include <wasi/core.h>
   7 #include <errno.h>
   8 #include <unistd.h>
   9
  10 static_assert(SEEK_CUR == __WASI_WHENCE_CUR, "Value mismatch");
  11 static_assert(SEEK_END == __WASI_WHENCE_END, "Value mismatch");
  12 static_assert(SEEK_SET == __WASI_WHENCE_SET, "Value mismatch");
  13
  14 #ifdef __wasilibc_unmodified_upstream /* Optimize the readonly case of lseek */
  15 off_t lseek(int fildes, off_t offset, int whence) {
  16 #else
  17 off_t (lseek)(int fildes, off_t offset, int whence) {
  18 #endif
  19   __wasi_filesize_t new_offset;
  20   __wasi_errno_t error =
  21       __wasi_fd_seek(fildes, offset, whence, &new_offset);
  22   if (error != 0) {
  23     errno = error == ENOTCAPABLE ? ESPIPE : error;
  24     return -1;
  25   }
  26   return new_offset;
  27 }