1  /*
       2   * Check decoding of pidfd_getfd syscall.
       3   *
       4   * Copyright (c) 2019 Dmitry V. Levin <ldv@strace.io>
       5   * Copyright (c) 2020-2021 The strace developers.
       6   * All rights reserved.
       7   *
       8   * SPDX-License-Identifier: GPL-2.0-or-later
       9   */
      10  
      11  #include "tests.h"
      12  #include "scno.h"
      13  
      14  #include <assert.h>
      15  #include <signal.h>
      16  #include <stdio.h>
      17  #include <stdlib.h>
      18  #include <unistd.h>
      19  #include <sys/wait.h>
      20  
      21  #ifndef PIDFD_PATH
      22  # define PIDFD_PATH ""
      23  #endif
      24  #ifndef FD0_PATH
      25  # define FD0_PATH ""
      26  #endif
      27  #ifndef PRINT_PIDFD
      28  # define PRINT_PIDFD 0
      29  #endif
      30  #ifndef SKIP_IF_PROC_IS_UNAVAILABLE
      31  # define SKIP_IF_PROC_IS_UNAVAILABLE
      32  #endif
      33  
      34  static const char *errstr;
      35  
      36  static long
      37  k_pidfd_getfd(const unsigned int pidfd, const unsigned int fd,
      38  	      const unsigned int flags)
      39  {
      40  	const kernel_ulong_t fill = (kernel_ulong_t) 0xdefaced00000000ULL;
      41  	const kernel_ulong_t bad = (kernel_ulong_t) 0xbadc0dedbadc0dedULL;
      42  	const kernel_ulong_t arg1 = fill | pidfd;
      43  	const kernel_ulong_t arg2 = fill | fd;
      44  	const kernel_ulong_t arg3 = fill | flags;
      45  	const long rc = syscall(__NR_pidfd_getfd,
      46  				arg1, arg2, arg3, bad, bad, bad);
      47  	errstr = sprintrc(rc);
      48  	return rc;
      49  }
      50  
      51  int
      52  main(void)
      53  {
      54  	SKIP_IF_PROC_IS_UNAVAILABLE;
      55  
      56  	long rc;
      57  
      58  	rc = k_pidfd_getfd(-1U, -1U, 0);
      59  	printf("pidfd_getfd(-1, -1, 0) = %s\n", errstr);
      60  
      61  	rc = k_pidfd_getfd(0, 0, 0xbadc0ded);
      62  	printf("pidfd_getfd(0" FD0_PATH ", 0, 0xbadc0ded) = %s\n", errstr);
      63  
      64  	int child_wait_fds[2];
      65  	if (pipe(child_wait_fds))
      66  		perror_msg_and_fail("pipe");
      67  
      68  	int dupfd = dup(0);
      69  	int pid = fork();
      70  	if (pid == 0) {
      71  		close(0);
      72  		close(child_wait_fds[1]);
      73  		if (read(child_wait_fds[0], &child_wait_fds[1], sizeof(int)))
      74  			_exit(2);
      75  		_exit(0);
      76  	}
      77  	close(dupfd);
      78  
      79  	int pidfd = syscall(__NR_pidfd_open, pid, 0);
      80  #if PRINT_PIDFD
      81  	char pidfd_str[sizeof("<pid:>") + 3 * sizeof(int)];
      82  	snprintf(pidfd_str, sizeof(pidfd_str), "<pid:%d>", pid);
      83  #else
      84  	const char *pidfd_str = PIDFD_PATH;
      85  #endif
      86  	rc = k_pidfd_getfd(pidfd, dupfd, 0);
      87  	printf("pidfd_getfd(%d%s, %d%s, 0) = %s%s\n",
      88  	       pidfd, pidfd >= 0 ? pidfd_str : "",
      89  	       dupfd, pidfd >= 0 ? FD0_PATH : "",
      90  	       errstr, rc >= 0 ? FD0_PATH : "");
      91  
      92  	puts("+++ exited with 0 +++");
      93  
      94  	close(child_wait_fds[1]);
      95  	int status;
      96  	assert(wait(&status) == pid);
      97  	assert(status == 0);
      98  
      99  	return 0;
     100  }