jcs.org
Serenity Operating System
1/*
2 * Copyright (c) 2021, Ben Wiederhake <BenWiederhake.GitHub@gmx.de>
3 *
4 * SPDX-License-Identifier: BSD-2-Clause
5 */
6
7#include <LibTest/TestCase.h>
8
9#include <AK/DeprecatedString.h>
10#include <AK/StringBuilder.h>
11#include <errno.h>
12#include <limits.h>
13#include <stdio.h>
14#include <stdlib.h>
15#include <string.h>
16#include <sys/stat.h>
17#include <unistd.h>
18
19static constexpr char TMPDIR_PATTERN[] = "/tmp/overlong_realpath_XXXXXX";
20static constexpr char PATH_LOREM_250[] = "This-is-an-annoyingly-long-name-that-should-take-up-exactly-two-hundred-and-fifty-characters-and-is-surprisingly-difficult-to-fill-with-reasonably-meaningful-text-which-is-necessary-because-that-makes-it-easier-for-my-eyes-to-spot-any-corruption-fast";
21
22static constexpr size_t ITERATION_DEPTH = 17;
23
24static void check_result(char const* what, DeprecatedString const& expected, char const* actual)
25{
26 if (expected != actual)
27 FAIL(DeprecatedString::formatted("Expected {} to be \"{}\" ({} characters)", what, actual, actual ? strlen(actual) : 0));
28}
29
30TEST_CASE(overlong_realpath)
31{
32 // We want to construct a path that is over PATH_MAX characters long.
33 // This cannot be done in a single step.
34
35 // First, switch to a known environment:
36 char tmp_dir[] = "/tmp/overlong_realpath_XXXXXX";
37
38 errno = 0;
39 auto* new_dir = mkdtemp(tmp_dir);
40 VERIFY(new_dir != nullptr);
41 VERIFY(errno == 0);
42
43 errno = 0;
44 auto ret = chdir(tmp_dir);
45 VERIFY(ret >= 0);
46 VERIFY(errno == 0);
47
48 // Then, create a long path.
49 StringBuilder expected;
50 expected.append({ tmp_dir, strlen(tmp_dir) });
51
52 // But first, demonstrate the functionality at a reasonable depth:
53 auto expected_str = expected.to_deprecated_string();
54 check_result("getwd", expected_str, getwd(static_cast<char*>(calloc(1, PATH_MAX))));
55 check_result("getcwd", expected_str, getcwd(nullptr, 0));
56 check_result("realpath", expected_str, realpath(".", nullptr));
57
58 for (size_t i = 0; i < ITERATION_DEPTH; ++i) {
59 ret = mkdir(PATH_LOREM_250, S_IRWXU);
60 if (ret < 0) {
61 perror("mkdir iter");
62 FAIL(DeprecatedString::formatted("Unable to mkdir the overlong path fragment in iteration {}", i));
63 return;
64 }
65 expected.append('/');
66 expected.append({ PATH_LOREM_250, strlen(PATH_LOREM_250) });
67 ret = chdir(PATH_LOREM_250);
68 if (ret < 0) {
69 perror("chdir iter");
70 FAIL(DeprecatedString::formatted("Unable to chdir to the overlong path fragment in iteration {}", i));
71 return;
72 }
73 }
74 outln("cwd should now be ridiculously large");
75
76 // Evaluate
77 expected_str = expected.to_deprecated_string();
78
79 check_result("getwd", {}, getwd(static_cast<char*>(calloc(1, PATH_MAX))));
80 check_result("getcwd", expected_str, getcwd(nullptr, 0));
81 check_result("realpath", expected_str, realpath(".", nullptr));
82
83 VERIFY(strlen(PATH_LOREM_250) == 250);
84 VERIFY(strlen(TMPDIR_PATTERN) + ITERATION_DEPTH * (1 + strlen(PATH_LOREM_250)) == expected_str.length());
85 VERIFY(expected_str.length() > PATH_MAX);
86}