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 25 static 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 48 static 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 63 static 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 80 static 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 87 static 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 } 115 116 out: 117 free(line); 118 fclose(f); 119 return result; 120 } 121 122 int 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; 158 159 on_error: 160 if (pidfd >= 0) 161 close(pidfd); 162 163 return !ret ? ksft_exit_pass() : ksft_exit_fail(); 164 } 165