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