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//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: no-filesystem
// setrlimit(RLIMIT_FSIZE) seems to only work as intended on Apple platforms
// REQUIRES: target={{.+}}-apple-{{.+}}
// <fstream>
// Make sure that we properly handle the case where we try to write content to a file
// but we fail to do so because std::fwrite fails.
#include <cassert>
#include <csignal>
#include <cstddef>
#include <fstream>
#include <string>
#include "platform_support.h"
#include "test_macros.h"
#if __has_include(<sys/resource.h>)
# include <sys/resource.h>
void limit_file_size_to(std::size_t bytes) {
rlimit lim = {bytes, bytes};
assert(setrlimit(RLIMIT_FSIZE, &lim) == 0);
std::signal(SIGXFSZ, [](int) {}); // ignore SIGXFSZ to ensure std::fwrite fails
}
#else
# error No known way to limit the amount of filesystem space available
#endif
template <class CharT>
void test() {
std::string temp = get_temp_file_name();
std::basic_filebuf<CharT> fbuf;
assert(fbuf.open(temp, std::ios::out | std::ios::trunc));
std::size_t const limit = 100000;
limit_file_size_to(limit);
std::basic_string<CharT> large_block(limit / 10, CharT(42));
std::streamsize ret;
std::size_t bytes_written = 0;
while ((ret = fbuf.sputn(large_block.data(), large_block.size())) != 0) {
bytes_written += ret;
// In theory, it's possible for an implementation to allow writing arbitrarily more bytes than
// set by setrlimit, but in practice if we bust 100x our limit, something else is wrong with the
// test and we'd end up looping forever.
assert(bytes_written < 100 * limit);
}
fbuf.close();
}
int main(int, char**) {
test<char>();
#ifndef TEST_HAS_NO_WIDE_CHARACTERS
test<wchar_t>();
#endif
return 0;
}
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