summaryrefslogtreecommitdiffstats
path: root/tools/testing/selftests/proc/read.c
blob: 1e73c22320972f1954b03d3485a29c9ad59ded86 (plain)
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
/*
 * 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
// 1) read of every file in /proc
// 2) readlink of every symlink in /proc
// 3) recursively (1) + (2) for every directory in /proc
// 4) write to /proc/*/clear_refs and /proc/*/task/*/clear_refs
// 5) write to /proc/sysrq-trigger
#undef NDEBUG
#include <assert.h>
#include <errno.h>
#include <sys/types.h>
#include <dirent.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

static inline bool streq(const char *s1, const char *s2)
{
	return strcmp(s1, s2) == 0;
}

static struct dirent *xreaddir(DIR *d)
{
	struct dirent *de;

	errno = 0;
	de = readdir(d);
	if (!de && errno != 0) {
		exit(1);
	}
	return de;
}

static void f_reg(DIR *d, const char *filename)
{
	char buf[4096];
	int fd;
	ssize_t rv;

	/* read from /proc/kmsg can block */
	fd = openat(dirfd(d), filename, O_RDONLY|O_NONBLOCK);
	if (fd == -1)
		return;
	rv = read(fd, buf, sizeof(buf));
	assert((0 <= rv && rv <= sizeof(buf)) || rv == -1);
	close(fd);
}

static void f_reg_write(DIR *d, const char *filename, const char *buf, size_t len)
{
	int fd;
	ssize_t rv;

	fd = openat(dirfd(d), filename, O_WRONLY);
	if (fd == -1)
		return;
	rv = write(fd, buf, len);
	assert((0 <= rv && rv <= len) || rv == -1);
	close(fd);
}

static void f_lnk(DIR *d, const char *filename)
{
	char buf[4096];
	ssize_t rv;

	rv = readlinkat(dirfd(d), filename, buf, sizeof(buf));
	assert((0 <= rv && rv <= sizeof(buf)) || rv == -1);
}

static void f(DIR *d, unsigned int level)
{
	struct dirent *de;

	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, ".."));

	while ((de = xreaddir(d))) {
		assert(!streq(de->d_name, "."));
		assert(!streq(de->d_name, ".."));

		switch (de->d_type) {
			DIR *dd;
			int fd;

		case DT_REG:
			if (level == 0 && streq(de->d_name, "sysrq-trigger")) {
				f_reg_write(d, de->d_name, "h", 1);
			} else if (level == 1 && streq(de->d_name, "clear_refs")) {
				f_reg_write(d, de->d_name, "1", 1);
			} else if (level == 3 && streq(de->d_name, "clear_refs")) {
				f_reg_write(d, de->d_name, "1", 1);
			} else {
				f_reg(d, de->d_name);
			}
			break;
		case DT_DIR:
			fd = openat(dirfd(d), de->d_name, O_DIRECTORY|O_RDONLY);
			if (fd == -1)
				continue;
			dd = fdopendir(fd);
			if (!dd)
				continue;
			f(dd, level + 1);
			closedir(dd);
			break;
		case DT_LNK:
			f_lnk(d, de->d_name);
			break;
		default:
			assert(0);
		}
	}
}

int main(void)
{
	DIR *d;

	d = opendir("/proc");
	if (!d)
		return 2;
	f(d, 0);
	return 0;
}