^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) #define _GNU_SOURCE
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) #include <err.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) #include <errno.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) #include <fcntl.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) #include <inttypes.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) #include <limits.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) #include <sched.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #include <signal.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) #include <stdio.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) #include <stdlib.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #include <string.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) #include <sys/stat.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) #include <sys/syscall.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) #include <sys/types.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) #include <sys/wait.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) #include <unistd.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) #ifndef CLONE_PIDFD
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) #define CLONE_PIDFD 0x00001000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) #ifndef __NR_pidfd_send_signal
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) #define __NR_pidfd_send_signal -1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) static int do_child(void *args)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) printf("%d\n", getpid());
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) _exit(EXIT_SUCCESS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) static pid_t pidfd_clone(int flags, int *pidfd)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) size_t stack_size = 1024;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) char *stack[1024] = { 0 };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) #ifdef __ia64__
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) return __clone2(do_child, stack, stack_size, flags | SIGCHLD, NULL, pidfd);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) #else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) return clone(do_child, stack + stack_size, flags | SIGCHLD, NULL, pidfd);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) static inline int sys_pidfd_send_signal(int pidfd, int sig, siginfo_t *info,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) unsigned int flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) return syscall(__NR_pidfd_send_signal, pidfd, sig, info, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) static int pidfd_metadata_fd(pid_t pid, int pidfd)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) int procfd, ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) char path[100];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) snprintf(path, sizeof(path), "/proc/%d", pid);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) procfd = open(path, O_DIRECTORY | O_RDONLY | O_CLOEXEC);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) if (procfd < 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) warn("Failed to open %s\n", path);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) return -1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) * Verify that the pid has not been recycled and our /proc/<pid> handle
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) * is still valid.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) ret = sys_pidfd_send_signal(pidfd, 0, NULL, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) if (ret < 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) switch (errno) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) case EPERM:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) /* Process exists, just not allowed to signal it. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) warn("Failed to signal process\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) close(procfd);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) procfd = -1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) return procfd;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) int main(int argc, char *argv[])
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) int pidfd = -1, ret = EXIT_FAILURE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) char buf[4096] = { 0 };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) pid_t pid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) int procfd, statusfd;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) ssize_t bytes;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) pid = pidfd_clone(CLONE_PIDFD, &pidfd);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) if (pid < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) err(ret, "CLONE_PIDFD");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) if (pidfd == -1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) warnx("CLONE_PIDFD is not supported by the kernel");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) procfd = pidfd_metadata_fd(pid, pidfd);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) close(pidfd);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) if (procfd < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) statusfd = openat(procfd, "status", O_RDONLY | O_CLOEXEC);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) close(procfd);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) if (statusfd < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) bytes = read(statusfd, buf, sizeof(buf));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) if (bytes > 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) bytes = write(STDOUT_FILENO, buf, bytes);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) close(statusfd);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) ret = EXIT_SUCCESS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) (void)wait(NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) exit(ret);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) }
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
3 Commits
0 Branches
0 Tags