libc/src/unistd/linux/readlinkat.cpp

   1 //===-- Linux implementation of readlinkat --------------------------------===//
   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/unistd/readlinkat.h"
  10
  11 #include "src/__support/OSUtil/syscall.h" // For internal syscall function.
  12 #include "src/__support/common.h"
  13
  14 #include "hdr/fcntl_macros.h"
  15 #include "src/__support/macros/config.h"
  16 #include "src/errno/libc_errno.h"
  17 #include <sys/syscall.h> // For syscall numbers.
  18
  19 namespace LIBC_NAMESPACE_DECL {
  20
  21 LLVM_LIBC_FUNCTION(ssize_t, readlinkat,
  22                    (int fd, const char *__restrict path, char *__restrict buf,
  23                     size_t bufsize)) {
  24   ssize_t ret = LIBC_NAMESPACE::syscall_impl<ssize_t>(SYS_readlinkat, fd, path,
  25                                                       buf, bufsize);
  26   if (ret < 0) {
  27     libc_errno = static_cast<int>(-ret);
  28     return -1;
  29   }
  30   return ret;
  31 }
  32
  33 } // namespace LIBC_NAMESPACE_DECL