1/* Test for /proc/self/fd (or /dev/fd) pathname construction.
2 Copyright (C) 2020-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <fcntl.h>
20#include <fd_to_filename.h>
21#include <stdio.h>
22#include <support/check.h>
23#include <support/xunistd.h>
24
25/* Run a check on one value. */
26static void
27check (int value)
28{
29 if (value < 0)
30 /* Negative descriptor values violate the precondition. */
31 return;
32
33 struct fd_to_filename storage;
34 char *actual = __fd_to_filename (descriptor: value, storage: &storage);
35 char expected[100];
36 snprintf (s: expected, maxlen: sizeof (expected), FD_TO_FILENAME_PREFIX "%d", value);
37 TEST_COMPARE_STRING (actual, expected);
38}
39
40/* Check various ranges constructed around powers. */
41static void
42check_ranges (int base)
43{
44 unsigned int power = 1;
45 do
46 {
47 for (int factor = 1; factor < base; ++factor)
48 for (int shift = -1000; shift <= 1000; ++shift)
49 check (value: factor * power + shift);
50 }
51 while (!__builtin_mul_overflow (power, base, &power));
52}
53
54/* Check that it is actually possible to use a the constructed
55 name. */
56static void
57check_open (void)
58{
59 int pipes[2];
60 xpipe (pipes);
61
62 struct fd_to_filename storage;
63 int read_alias = xopen (path: __fd_to_filename (descriptor: pipes[0], storage: &storage), O_RDONLY, 0);
64 int write_alias = xopen (path: __fd_to_filename (descriptor: pipes[1], storage: &storage), O_WRONLY, 0);
65
66 /* Ensure that all the descriptor numbers are different. */
67 TEST_VERIFY (pipes[0] < pipes[1]);
68 TEST_VERIFY (pipes[1] < read_alias);
69 TEST_VERIFY (read_alias < write_alias);
70
71 xwrite (write_alias, "1", 1);
72 char buf[16];
73 TEST_COMPARE_BLOB ("1", 1, buf, read (pipes[0], buf, sizeof (buf)));
74
75 xwrite (pipes[1], "2", 1);
76 TEST_COMPARE_BLOB ("2", 1, buf, read (read_alias, buf, sizeof (buf)));
77
78 xwrite (write_alias, "3", 1);
79 TEST_COMPARE_BLOB ("3", 1, buf, read (read_alias, buf, sizeof (buf)));
80
81 xwrite (pipes[1], "4", 1);
82 TEST_COMPARE_BLOB ("4", 1, buf, read (pipes[0], buf, sizeof (buf)));
83
84 xclose (write_alias);
85 xclose (read_alias);
86 xclose (pipes[1]);
87 xclose (pipes[0]);
88}
89
90static int
91do_test (void)
92{
93 check_ranges (base: 2);
94 check_ranges (base: 10);
95
96 check_open ();
97
98 return 0;
99}
100
101#include <support/test-driver.c>
102

source code of glibc/misc/tst-fd_to_filename.c