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
 24static 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
 47static 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
 62static 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
 79static 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
 86static 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
115out:
116	free(line);
117	fclose(f);
118	return result;
119}
120
121int 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
158on_error:
159	if (pidfd >= 0)
160		close(pidfd);
161
162	return !ret ? ksft_exit_pass() : ksft_exit_fail();
163}