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 <sched.h>
10 #include <signal.h>
11 #include <stdbool.h>
12 #include <stdio.h>
13 #include <stdlib.h>
14 #include <string.h>
15 #include <syscall.h>
16 #include <sys/mount.h>
17 #include <sys/prctl.h>
18 #include <sys/wait.h>
19 #include <unistd.h>
20
21 #include "pidfd.h"
22 #include "../kselftest.h"
23
24 static int safe_int(const char *numstr, int *converted)
25 {
26 char *err = NULL;
27 long sli;
28
29 errno = 0;
30 sli = strtol(numstr, &err, 0);
31 if (errno == ERANGE && (sli == LONG_MAX || sli == LONG_MIN))
32 return -ERANGE;
33
34 if (errno != 0 && sli == 0)
35 return -EINVAL;
36
37 if (err == numstr || *err != '\0')
38 return -EINVAL;
39
40 if (sli > INT_MAX || sli < INT_MIN)
41 return -ERANGE;
42
43 *converted = (int)sli;
44 return 0;
45 }
46
47 static int char_left_gc(const char *buffer, size_t len)
48 {
49 size_t i;
50
51 for (i = 0; i < len; i++) {
52 if (buffer[i] == ' ' ||
53 buffer[i] == '\t')
54 continue;
55
56 return i;
57 }
58
59 return 0;
60 }
61
62 static int char_right_gc(const char *buffer, size_t len)
63 {
64 int i;
65
66 for (i = len - 1; i >= 0; i--) {
67 if (buffer[i] == ' ' ||
68 buffer[i] == '\t' ||
69 buffer[i] == '\n' ||
70 buffer[i] == '\0')
71 continue;
72
73 return i + 1;
74 }
75
76 return 0;
77 }
78
79 static char *trim_whitespace_in_place(char *buffer)
80 {
81 buffer += char_left_gc(buffer, strlen(buffer));
82 buffer[char_right_gc(buffer, strlen(buffer))] = '\0';
83 return buffer;
84 }
85
86 static pid_t get_pid_from_fdinfo_file(int pidfd, const char *key, size_t keylen)
87 {
88 int ret;
89 char path[512];
90 FILE *f;
91 size_t n = 0;
92 pid_t result = -1;
93 char *line = NULL;
94
95 snprintf(path, sizeof(path), "/proc/self/fdinfo/%d", pidfd);
96
97 f = fopen(path, "re");
98 if (!f)
99 return -1;
100
101 while (getline(&line, &n, f) != -1) {
102 char *numstr;
103
104 if (strncmp(line, key, keylen))
105 continue;
106
107 numstr = trim_whitespace_in_place(line + 4);
108 ret = safe_int(numstr, &result);
109 if (ret < 0)
110 goto out;
111
112 break;
113 }
114
115 out:
116 free(line);
117 fclose(f);
118 return result;
119 }
120
121 int main(int argc, char **argv)
122 {
123 int pidfd = -1, ret = 1;
124 pid_t pid;
125
126 ksft_set_plan(3);
127
128 pidfd = sys_pidfd_open(-1, 0);
129 if (pidfd >= 0) {
130 ksft_print_msg(
131 "%s - succeeded to open pidfd for invalid pid -1\n",
132 strerror(errno));
133 goto on_error;
134 }
135 ksft_test_result_pass("do not allow invalid pid test: passed\n");
136
137 pidfd = sys_pidfd_open(getpid(), 1);
138 if (pidfd >= 0) {
139 ksft_print_msg(
140 "%s - succeeded to open pidfd with invalid flag value specified\n",
141 strerror(errno));
142 goto on_error;
143 }
144 ksft_test_result_pass("do not allow invalid flag test: passed\n");
145
146 pidfd = sys_pidfd_open(getpid(), 0);
147 if (pidfd < 0) {
148 ksft_print_msg("%s - failed to open pidfd\n", strerror(errno));
149 goto on_error;
150 }
151 ksft_test_result_pass("open a new pidfd test: passed\n");
152
153 pid = get_pid_from_fdinfo_file(pidfd, "Pid:", sizeof("Pid:") - 1);
154 ksft_print_msg("pidfd %d refers to process with pid %d\n", pidfd, pid);
155
156 ret = 0;
157
158 on_error:
159 if (pidfd >= 0)
160 close(pidfd);
161
162 if (ret)
163 ksft_exit_fail();
164 ksft_exit_pass();
165 }
166
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