summaryrefslogtreecommitdiff
path: root/tools/testing/selftests/pidfd/pidfd_open_test.c
blob: 0377133dd6dceab6748b206a6c6cfa55cfa32472 (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
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
// SPDX-License-Identifier: GPL-2.0

#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <limits.h>
#include <linux/types.h>
#include <linux/wait.h>
#include <sched.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syscall.h>
#include <sys/mount.h>
#include <sys/prctl.h>
#include <sys/wait.h>
#include <unistd.h>

#include "pidfd.h"
#include "../kselftest.h"

static inline int sys_pidfd_open(pid_t pid, unsigned int flags)
{
	return syscall(__NR_pidfd_open, pid, flags);
}

static int safe_int(const char *numstr, int *converted)
{
	char *err = NULL;
	long sli;

	errno = 0;
	sli = strtol(numstr, &err, 0);
	if (errno == ERANGE && (sli == LONG_MAX || sli == LONG_MIN))
		return -ERANGE;

	if (errno != 0 && sli == 0)
		return -EINVAL;

	if (err == numstr || *err != '\0')
		return -EINVAL;

	if (sli > INT_MAX || sli < INT_MIN)
		return -ERANGE;

	*converted = (int)sli;
	return 0;
}

static int char_left_gc(const char *buffer, size_t len)
{
	size_t i;

	for (i = 0; i < len; i++) {
		if (buffer[i] == ' ' ||
		    buffer[i] == '\t')
			continue;

		return i;
	}

	return 0;
}

static int char_right_gc(const char *buffer, size_t len)
{
	int i;

	for (i = len - 1; i >= 0; i--) {
		if (buffer[i] == ' '  ||
		    buffer[i] == '\t' ||
		    buffer[i] == '\n' ||
		    buffer[i] == '\0')
			continue;

		return i + 1;
	}

	return 0;
}

static char *trim_whitespace_in_place(char *buffer)
{
	buffer += char_left_gc(buffer, strlen(buffer));
	buffer[char_right_gc(buffer, strlen(buffer))] = '\0';
	return buffer;
}

static pid_t get_pid_from_fdinfo_file(int pidfd, const char *key, size_t keylen)
{
	int ret;
	char path[512];
	FILE *f;
	size_t n = 0;
	pid_t result = -1;
	char *line = NULL;

	snprintf(path, sizeof(path), "/proc/self/fdinfo/%d", pidfd);

	f = fopen(path, "re");
	if (!f)
		return -1;

	while (getline(&line, &n, f) != -1) {
		char *numstr;

		if (strncmp(line, key, keylen))
			continue;

		numstr = trim_whitespace_in_place(line + 4);
		ret = safe_int(numstr, &result);
		if (ret < 0)
			goto out;

		break;
	}

out:
	free(line);
	fclose(f);
	return result;
}

int main(int argc, char **argv)
{
	int pidfd = -1, ret = 1;
	pid_t pid;

	ksft_set_plan(3);

	pidfd = sys_pidfd_open(-1, 0);
	if (pidfd >= 0) {
		ksft_print_msg(
			"%s - succeeded to open pidfd for invalid pid -1\n",
			strerror(errno));
		goto on_error;
	}
	ksft_test_result_pass("do not allow invalid pid test: passed\n");

	pidfd = sys_pidfd_open(getpid(), 1);
	if (pidfd >= 0) {
		ksft_print_msg(
			"%s - succeeded to open pidfd with invalid flag value specified\n",
			strerror(errno));
		goto on_error;
	}
	ksft_test_result_pass("do not allow invalid flag test: passed\n");

	pidfd = sys_pidfd_open(getpid(), 0);
	if (pidfd < 0) {
		ksft_print_msg("%s - failed to open pidfd\n", strerror(errno));
		goto on_error;
	}
	ksft_test_result_pass("open a new pidfd test: passed\n");

	pid = get_pid_from_fdinfo_file(pidfd, "Pid:", sizeof("Pid:") - 1);
	ksft_print_msg("pidfd %d refers to process with pid %d\n", pidfd, pid);

	ret = 0;

on_error:
	if (pidfd >= 0)
		close(pidfd);

	return !ret ? ksft_exit_pass() : ksft_exit_fail();
}