1 /*
2 * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com>
3 *
4 * Permission to use, copy, modify, and distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 */
16 // Test /proc/*/fd lookup.
17
18 #undef NDEBUG
19 #include <assert.h>
20 #include <dirent.h>
21 #include <errno.h>
22 #include <limits.h>
23 #include <sched.h>
24 #include <stdio.h>
25 #include <unistd.h>
26 #include <sys/types.h>
27 #include <sys/stat.h>
28 #include <fcntl.h>
29
30 #include "proc.h"
31
32 /* lstat(2) has more "coverage" in case non-symlink pops up somehow. */
test_lookup_pass(const char * pathname)33 static void test_lookup_pass(const char *pathname)
34 {
35 struct stat st;
36 ssize_t rv;
37
38 memset(&st, 0, sizeof(struct stat));
39 rv = lstat(pathname, &st);
40 assert(rv == 0);
41 assert(S_ISLNK(st.st_mode));
42 }
43
test_lookup_fail(const char * pathname)44 static void test_lookup_fail(const char *pathname)
45 {
46 struct stat st;
47 ssize_t rv;
48
49 rv = lstat(pathname, &st);
50 assert(rv == -1 && errno == ENOENT);
51 }
52
test_lookup(unsigned int fd)53 static void test_lookup(unsigned int fd)
54 {
55 char buf[64];
56 unsigned int c;
57 unsigned int u;
58 int i;
59
60 snprintf(buf, sizeof(buf), "/proc/self/fd/%u", fd);
61 test_lookup_pass(buf);
62
63 /* leading junk */
64 for (c = 1; c <= 255; c++) {
65 if (c == '/')
66 continue;
67 snprintf(buf, sizeof(buf), "/proc/self/fd/%c%u", c, fd);
68 test_lookup_fail(buf);
69 }
70
71 /* trailing junk */
72 for (c = 1; c <= 255; c++) {
73 if (c == '/')
74 continue;
75 snprintf(buf, sizeof(buf), "/proc/self/fd/%u%c", fd, c);
76 test_lookup_fail(buf);
77 }
78
79 for (i = INT_MIN; i < INT_MIN + 1024; i++) {
80 snprintf(buf, sizeof(buf), "/proc/self/fd/%d", i);
81 test_lookup_fail(buf);
82 }
83 for (i = -1024; i < 0; i++) {
84 snprintf(buf, sizeof(buf), "/proc/self/fd/%d", i);
85 test_lookup_fail(buf);
86 }
87 for (u = INT_MAX - 1024; u <= (unsigned int)INT_MAX + 1024; u++) {
88 snprintf(buf, sizeof(buf), "/proc/self/fd/%u", u);
89 test_lookup_fail(buf);
90 }
91 for (u = UINT_MAX - 1024; u != 0; u++) {
92 snprintf(buf, sizeof(buf), "/proc/self/fd/%u", u);
93 test_lookup_fail(buf);
94 }
95
96
97 }
98
main(void)99 int main(void)
100 {
101 struct dirent *de;
102 unsigned int fd, target_fd;
103
104 if (unshare(CLONE_FILES) == -1)
105 return 1;
106
107 /* Wipe fdtable. */
108 do {
109 DIR *d;
110
111 d = opendir("/proc/self/fd");
112 if (!d)
113 return 1;
114
115 de = xreaddir(d);
116 assert(de->d_type == DT_DIR);
117 assert(streq(de->d_name, "."));
118
119 de = xreaddir(d);
120 assert(de->d_type == DT_DIR);
121 assert(streq(de->d_name, ".."));
122 next:
123 de = xreaddir(d);
124 if (de) {
125 unsigned long long fd_ull;
126 unsigned int fd;
127 char *end;
128
129 assert(de->d_type == DT_LNK);
130
131 fd_ull = xstrtoull(de->d_name, &end);
132 assert(*end == '\0');
133 assert(fd_ull == (unsigned int)fd_ull);
134
135 fd = fd_ull;
136 if (fd == dirfd(d))
137 goto next;
138 close(fd);
139 }
140
141 closedir(d);
142 } while (de);
143
144 /* Now fdtable is clean. */
145
146 fd = open("/", O_PATH|O_DIRECTORY);
147 assert(fd == 0);
148 test_lookup(fd);
149 close(fd);
150
151 /* Clean again! */
152
153 fd = open("/", O_PATH|O_DIRECTORY);
154 assert(fd == 0);
155 /* Default RLIMIT_NOFILE-1 */
156 target_fd = 1023;
157 while (target_fd > 0) {
158 if (dup2(fd, target_fd) == target_fd)
159 break;
160 target_fd /= 2;
161 }
162 assert(target_fd > 0);
163 close(fd);
164 test_lookup(target_fd);
165 close(target_fd);
166
167 return 0;
168 }
169