166 lines · c
1// SPDX-License-Identifier: GPL-2.02 3#define _GNU_SOURCE4#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 if (ret)163 ksft_exit_fail();164 ksft_exit_pass();165}166