1 | /* Test for reading directories with getdents64. |
2 | Copyright (C) 2019-2024 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 <dirent.h> |
20 | #include <errno.h> |
21 | #include <fcntl.h> |
22 | #include <limits.h> |
23 | #include <stdbool.h> |
24 | #include <stdio.h> |
25 | #include <stdlib.h> |
26 | #include <string.h> |
27 | #include <support/check.h> |
28 | #include <support/support.h> |
29 | #include <support/xunistd.h> |
30 | #include <sys/mman.h> |
31 | #include <unistd.h> |
32 | |
33 | /* Called by large_buffer_checks below. */ |
34 | static void |
35 | large_buffer_check (int fd, char *large_buffer, size_t large_buffer_size) |
36 | { |
37 | xlseek (fd, offset: 0, SEEK_SET); |
38 | ssize_t ret = getdents64 (fd: fd, buffer: large_buffer, length: large_buffer_size); |
39 | if (ret < 0) |
40 | FAIL_EXIT1 ("getdents64 for buffer of %zu bytes failed: %m" , |
41 | large_buffer_size); |
42 | if (ret < offsetof (struct dirent64, d_name)) |
43 | FAIL_EXIT1 ("getdents64 for buffer of %zu returned small value %zd" , |
44 | large_buffer_size, ret); |
45 | } |
46 | |
47 | /* Bug 24740: Make sure that the system call argument is adjusted |
48 | properly for the int type. A large value should stay a large |
49 | value, and not wrap around to something small, causing the system |
50 | call to fail with EINVAL. */ |
51 | static void |
52 | large_buffer_checks (int fd) |
53 | { |
54 | size_t large_buffer_size; |
55 | if (!__builtin_add_overflow (UINT_MAX, 2, &large_buffer_size)) |
56 | { |
57 | int flags = MAP_ANONYMOUS | MAP_PRIVATE; |
58 | #ifdef MAP_NORESERVE |
59 | flags |= MAP_NORESERVE; |
60 | #endif |
61 | void *large_buffer = mmap (NULL, len: large_buffer_size, |
62 | PROT_READ | PROT_WRITE, flags: flags, fd: -1, offset: 0); |
63 | if (large_buffer == MAP_FAILED) |
64 | printf (format: "warning: could not allocate %zu bytes of memory," |
65 | " subtests skipped\n" , large_buffer_size); |
66 | else |
67 | { |
68 | large_buffer_check (fd, large_buffer, INT_MAX); |
69 | large_buffer_check (fd, large_buffer, large_buffer_size: (size_t) INT_MAX + 1); |
70 | large_buffer_check (fd, large_buffer, large_buffer_size: (size_t) INT_MAX + 2); |
71 | large_buffer_check (fd, large_buffer, UINT_MAX); |
72 | large_buffer_check (fd, large_buffer, large_buffer_size: (size_t) UINT_MAX + 1); |
73 | large_buffer_check (fd, large_buffer, large_buffer_size: (size_t) UINT_MAX + 2); |
74 | xmunmap (addr: large_buffer, length: large_buffer_size); |
75 | } |
76 | } |
77 | } |
78 | |
79 | static void |
80 | do_test_large_size (void) |
81 | { |
82 | int fd = xopen (path: "." , O_RDONLY | O_DIRECTORY, 0); |
83 | TEST_VERIFY (fd >= 0); |
84 | large_buffer_checks (fd); |
85 | |
86 | xclose (fd); |
87 | } |
88 | |
89 | static void |
90 | do_test_by_size (size_t buffer_size) |
91 | { |
92 | /* The test compares the iteration order with readdir64. */ |
93 | DIR *reference = opendir (name: "." ); |
94 | TEST_VERIFY_EXIT (reference != NULL); |
95 | |
96 | int fd = xopen (path: "." , O_RDONLY | O_DIRECTORY, 0); |
97 | TEST_VERIFY (fd >= 0); |
98 | |
99 | /* Perform two passes, with a rewind operating between passes. */ |
100 | for (int pass = 0; pass < 2; ++pass) |
101 | { |
102 | /* Check that we need to fill the buffer multiple times. */ |
103 | int read_count = 0; |
104 | |
105 | while (true) |
106 | { |
107 | /* Simple way to make sure that the memcpy below does not read |
108 | non-existing data. */ |
109 | struct |
110 | { |
111 | char buffer[buffer_size]; |
112 | struct dirent64 pad; |
113 | } data; |
114 | |
115 | ssize_t ret = getdents64 (fd: fd, buffer: &data.buffer, length: sizeof (data.buffer)); |
116 | if (ret < 0) |
117 | FAIL_EXIT1 ("getdents64: %m" ); |
118 | if (ret == 0) |
119 | break; |
120 | ++read_count; |
121 | |
122 | char *current = data.buffer; |
123 | char *end = data.buffer + ret; |
124 | while (current != end) |
125 | { |
126 | struct dirent64 entry; |
127 | memcpy (&entry, current, sizeof (entry)); |
128 | /* Truncate overlong strings. */ |
129 | entry.d_name[sizeof (entry.d_name) - 1] = '\0'; |
130 | TEST_VERIFY (strlen (entry.d_name) < sizeof (entry.d_name) - 1); |
131 | |
132 | errno = 0; |
133 | struct dirent64 *refentry = readdir64 (dirp: reference); |
134 | if (refentry == NULL && errno == 0) |
135 | FAIL_EXIT1 ("readdir64 failed too early, at: %s" , |
136 | entry.d_name); |
137 | else if (refentry == NULL) |
138 | FAIL_EXIT1 ("readdir64: %m" ); |
139 | |
140 | TEST_COMPARE_STRING (entry.d_name, refentry->d_name); |
141 | TEST_COMPARE (entry.d_ino, refentry->d_ino); |
142 | TEST_COMPARE (entry.d_off, refentry->d_off); |
143 | TEST_COMPARE (entry.d_type, refentry->d_type); |
144 | |
145 | /* Offset zero is reserved for the first entry. */ |
146 | TEST_VERIFY (entry.d_off != 0); |
147 | |
148 | TEST_VERIFY_EXIT (entry.d_reclen <= end - current); |
149 | current += entry.d_reclen; |
150 | } |
151 | } |
152 | |
153 | /* We expect to have reached the end of the stream. */ |
154 | errno = 0; |
155 | TEST_VERIFY (readdir64 (reference) == NULL); |
156 | TEST_COMPARE (errno, 0); |
157 | |
158 | /* direntries_read has been called more than once. */ |
159 | TEST_VERIFY (read_count > 0); |
160 | |
161 | /* Rewind both directory streams. */ |
162 | xlseek (fd, offset: 0, SEEK_SET); |
163 | rewinddir (dirp: reference); |
164 | } |
165 | |
166 | xclose (fd); |
167 | closedir (dirp: reference); |
168 | } |
169 | |
170 | static int |
171 | do_test (void) |
172 | { |
173 | do_test_by_size (buffer_size: 512); |
174 | do_test_by_size (buffer_size: 1024); |
175 | do_test_by_size (buffer_size: 4096); |
176 | |
177 | do_test_large_size (); |
178 | |
179 | return 0; |
180 | } |
181 | |
182 | #include <support/test-driver.c> |
183 | |