1  /*
       2   * Check decoding of return values injected into a syscall that "never fails".
       3   *
       4   * Copyright (c) 2018-2020 The strace developers.
       5   * All rights reserved.
       6   *
       7   * SPDX-License-Identifier: GPL-2.0-or-later
       8   */
       9  
      10  #include "tests.h"
      11  
      12  #include <assert.h>
      13  #include <stdio.h>
      14  #include <stdlib.h>
      15  #include "scno.h"
      16  
      17  #include "raw_syscall.h"
      18  
      19  #ifdef __NR_geteuid32
      20  # define SC_NR __NR_geteuid32
      21  # define SC_NAME "geteuid32"
      22  #else
      23  # define SC_NR __NR_geteuid
      24  # define SC_NAME "geteuid"
      25  #endif
      26  
      27  #ifdef raw_syscall_0
      28  # define INVOKE_SC(err) raw_syscall_0(SC_NR, &err)
      29  #else
      30  /* No raw_syscall_0, let's use geteuid() and hope for the best. */
      31  # define INVOKE_SC(err) geteuid()
      32  #endif
      33  
      34  /*
      35   * This prototype is intentionally different
      36   * from the prototype provided by <unistd.h>.
      37   */
      38  extern kernel_ulong_t geteuid(void);
      39  
      40  int
      41  main(int ac, char **av)
      42  {
      43  	assert(ac == 1 || ac == 2);
      44  
      45  	kernel_ulong_t expected =
      46  		(ac == 1) ? geteuid() : strtoull(av[1], NULL, 0);
      47  	kernel_ulong_t err = 0;
      48  	kernel_ulong_t rc = INVOKE_SC(err);
      49  
      50  	if (err || rc != expected)
      51  		error_msg_and_fail("expected %#llx, got rval=%#llx err=%#llx",
      52  				   (unsigned long long) expected,
      53  				   (unsigned long long) rc,
      54  				   (unsigned long long) err);
      55  
      56  	if (ac == 2) {
      57  		printf("%s() = %llu (INJECTED)\n",
      58  		       SC_NAME, (unsigned long long) rc);
      59  
      60  		puts("+++ exited with 0 +++");
      61  	}
      62  
      63  	return 0;
      64  }