//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
/// \file
/// Implementation of the POSIX setenv function.
///
//===----------------------------------------------------------------------===//

#include "src/stdlib/setenv.h"
#include "src/__support/CPP/string_view.h"
#include "src/__support/common.h"
#include "src/__support/libc_errno.h"
#include "src/__support/macros/config.h"
#include "src/__support/macros/null_check.h"
#include "src/stdlib/environ_internal.h"

namespace LIBC_NAMESPACE_DECL {

LLVM_LIBC_FUNCTION(int, setenv,
                   (const char *name, const char *value, int overwrite)) {
  // Passing nullptr for either argument is undefined behavior per POSIX,
  // so crash rather than returning an error.
  LIBC_CRASH_ON_NULLPTR(name);
  LIBC_CRASH_ON_NULLPTR(value);

  cpp::string_view name_view(name);

  // POSIX: name must not be empty or contain '='.
  if (name_view.empty() ||
      name_view.find_first_of('=') != cpp::string_view::npos) {
    libc_errno = EINVAL;
    return -1;
  }

  int result = internal::EnvironmentManager::get_instance().set(
      name_view, value, overwrite != 0);
  if (result != 0)
    libc_errno = ENOMEM;

  return result;
}

} // namespace LIBC_NAMESPACE_DECL