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

   1 // Copyright (c) 2015-2016 Nuxi, https://nuxi.nl/
   2 //
   3 // SPDX-License-Identifier: BSD-2-Clause
   4
   5 #include <wasi/api.h>
   6 #include <errno.h>
   7 #include <unistd.h>
   8
   9 ssize_t pwrite(int fildes, const void *buf, size_t nbyte, off_t offset) {
  10   if (offset < 0) {
  11     errno = EINVAL;
  12     return -1;
  13   }
  14   __wasi_ciovec_t iov = {.buf = buf, .buf_len = nbyte};
  15   size_t bytes_written;
  16   __wasi_errno_t error =
  17       __wasi_fd_pwrite(fildes, &iov, 1, offset, &bytes_written);
  18   if (error != 0) {
  19     __wasi_fdstat_t fds;
  20 #ifdef __wasilibc_unmodified_upstream
  21     if (error == ENOTCAPABLE && __wasi_fd_stat_get(fildes, &fds) == 0) {
  22 #else
  23     if (error == ENOTCAPABLE && __wasi_fd_fdstat_get(fildes, &fds) == 0) {
  24 #endif
  25       // Determine why we got ENOTCAPABLE.
  26 #ifdef __wasilibc_unmodified_upstream // generated constant names
  27       if ((fds.fs_rights_base & __WASI_RIGHT_FD_WRITE) == 0)
  28 #else
  29       if ((fds.fs_rights_base & __WASI_RIGHTS_FD_WRITE) == 0)
  30 #endif
  31         error = EBADF;
  32       else
  33         error = ESPIPE;
  34     }
  35     errno = error;
  36     return -1;
  37   }
  38   return bytes_written;
  39 }