Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2
3#define _GNU_SOURCE
4#include <errno.h>
5#include <fcntl.h>
6#include <inttypes.h>
7#include <limits.h>
8#include <linux/types.h>
9#include <linux/wait.h>
10#include <sched.h>
11#include <signal.h>
12#include <stdbool.h>
13#include <stdio.h>
14#include <stdlib.h>
15#include <string.h>
16#include <syscall.h>
17#include <sys/mount.h>
18#include <sys/prctl.h>
19#include <sys/wait.h>
20#include <unistd.h>
21
22#include "pidfd.h"
23#include "../kselftest.h"
24
25static int safe_int(const char *numstr, int *converted)
26{
27 char *err = NULL;
28 long sli;
29
30 errno = 0;
31 sli = strtol(numstr, &err, 0);
32 if (errno == ERANGE && (sli == LONG_MAX || sli == LONG_MIN))
33 return -ERANGE;
34
35 if (errno != 0 && sli == 0)
36 return -EINVAL;
37
38 if (err == numstr || *err != '\0')
39 return -EINVAL;
40
41 if (sli > INT_MAX || sli < INT_MIN)
42 return -ERANGE;
43
44 *converted = (int)sli;
45 return 0;
46}
47
48static int char_left_gc(const char *buffer, size_t len)
49{
50 size_t i;
51
52 for (i = 0; i < len; i++) {
53 if (buffer[i] == ' ' ||
54 buffer[i] == '\t')
55 continue;
56
57 return i;
58 }
59
60 return 0;
61}
62
63static int char_right_gc(const char *buffer, size_t len)
64{
65 int i;
66
67 for (i = len - 1; i >= 0; i--) {
68 if (buffer[i] == ' ' ||
69 buffer[i] == '\t' ||
70 buffer[i] == '\n' ||
71 buffer[i] == '\0')
72 continue;
73
74 return i + 1;
75 }
76
77 return 0;
78}
79
80static char *trim_whitespace_in_place(char *buffer)
81{
82 buffer += char_left_gc(buffer, strlen(buffer));
83 buffer[char_right_gc(buffer, strlen(buffer))] = '\0';
84 return buffer;
85}
86
87static pid_t get_pid_from_fdinfo_file(int pidfd, const char *key, size_t keylen)
88{
89 int ret;
90 char path[512];
91 FILE *f;
92 size_t n = 0;
93 pid_t result = -1;
94 char *line = NULL;
95
96 snprintf(path, sizeof(path), "/proc/self/fdinfo/%d", pidfd);
97
98 f = fopen(path, "re");
99 if (!f)
100 return -1;
101
102 while (getline(&line, &n, f) != -1) {
103 char *numstr;
104
105 if (strncmp(line, key, keylen))
106 continue;
107
108 numstr = trim_whitespace_in_place(line + 4);
109 ret = safe_int(numstr, &result);
110 if (ret < 0)
111 goto out;
112
113 break;
114 }
115
116out:
117 free(line);
118 fclose(f);
119 return result;
120}
121
122int main(int argc, char **argv)
123{
124 int pidfd = -1, ret = 1;
125 pid_t pid;
126
127 ksft_set_plan(3);
128
129 pidfd = sys_pidfd_open(-1, 0);
130 if (pidfd >= 0) {
131 ksft_print_msg(
132 "%s - succeeded to open pidfd for invalid pid -1\n",
133 strerror(errno));
134 goto on_error;
135 }
136 ksft_test_result_pass("do not allow invalid pid test: passed\n");
137
138 pidfd = sys_pidfd_open(getpid(), 1);
139 if (pidfd >= 0) {
140 ksft_print_msg(
141 "%s - succeeded to open pidfd with invalid flag value specified\n",
142 strerror(errno));
143 goto on_error;
144 }
145 ksft_test_result_pass("do not allow invalid flag test: passed\n");
146
147 pidfd = sys_pidfd_open(getpid(), 0);
148 if (pidfd < 0) {
149 ksft_print_msg("%s - failed to open pidfd\n", strerror(errno));
150 goto on_error;
151 }
152 ksft_test_result_pass("open a new pidfd test: passed\n");
153
154 pid = get_pid_from_fdinfo_file(pidfd, "Pid:", sizeof("Pid:") - 1);
155 ksft_print_msg("pidfd %d refers to process with pid %d\n", pidfd, pid);
156
157 ret = 0;
158
159on_error:
160 if (pidfd >= 0)
161 close(pidfd);
162
163 return !ret ? ksft_exit_pass() : ksft_exit_fail();
164}