libc/src/sys/sendfile/linux/sendfile.cpp

   1 //===-- Linux implementation of sendfile ----------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "src/sys/sendfile/sendfile.h"
  10
  11 #include "src/__support/OSUtil/syscall.h" // For internal syscall function.
  12 #include "src/__support/common.h"
  13
  14 #include "src/errno/libc_errno.h"
  15 #include <sys/sendfile.h>
  16 #include <sys/syscall.h> // For syscall numbers.
  17
  18 namespace LIBC_NAMESPACE {
  19
  20 LLVM_LIBC_FUNCTION(ssize_t, sendfile,
  21                    (int out_fd, int in_fd, off_t *offset, size_t count)) {
  22 #ifdef SYS_sendfile
  23   ssize_t ret = LIBC_NAMESPACE::syscall_impl<ssize_t>(SYS_sendfile, in_fd,
  24                                                       out_fd, offset, count);
  25 #elif defined(SYS_sendfile64)
  26   // Same as sendfile but can handle large offsets
  27   static_assert(sizeof(off_t) == 8);
  28   ssize_t ret = LIBC_NAMESPACE::syscall_impl<ssize_t>(SYS_sendfile64, in_fd,
  29                                                       out_fd, offset, count);
  30 #else
  31 #error "sendfile and sendfile64 syscalls not available."
  32 #endif
  33   if (ret < 0) {
  34     libc_errno = static_cast<int>(-ret);
  35     return -1;
  36   }
  37   return ret;
  38 }
  39
  40 } // namespace LIBC_NAMESPACE