1  /* Test the sprintf (buf, "%s", buf) does not override buf.
       2     Copyright (C) 2019-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <stdarg.h>
      20  #include <stdio.h>
      21  #include <string.h>
      22  
      23  #include <support/check.h>
      24  
      25  enum
      26  {
      27    FUNCTION_FIRST,
      28    FUNCTION_SPRINTF = FUNCTION_FIRST,
      29    FUNCTION_SNPRINF,
      30    FUNCTION_VSPRINTF,
      31    FUNCTION_VSNPRINTF,
      32    FUNCTION_LAST
      33  };
      34  
      35  static void
      36  do_one_test (int function, char *buf, ...)
      37  {
      38    va_list args;
      39    char *arg;
      40  
      41    /* Expected results for fortified and non-fortified sprintf.  */
      42  #if defined _FORTIFY_SOURCE && _FORTIFY_SOURCE > 1
      43    const char *expected = "CD";
      44  #else
      45    const char *expected = "ABCD";
      46  #endif
      47  
      48    va_start (args, buf);
      49    arg = va_arg (args, char *);
      50    va_end (args);
      51  
      52    switch (function)
      53      {
      54        /* The regular sprintf and vsprintf functions do not override the
      55           destination buffer, even if source and destination overlap.  */
      56        case FUNCTION_SPRINTF:
      57          sprintf (buf, "%sCD", buf);
      58          TEST_COMPARE_STRING (buf, expected);
      59          break;
      60        case FUNCTION_VSPRINTF:
      61          va_start (args, buf);
      62          vsprintf (arg, "%sCD", args);
      63          TEST_COMPARE_STRING (arg, expected);
      64          va_end (args);
      65          break;
      66        /* On the other hand, snprint and vsnprint override overlapping
      67           source and destination buffers.  */
      68        case FUNCTION_SNPRINF:
      69          snprintf (buf, 3, "%sCD", buf);
      70          TEST_COMPARE_STRING (buf, "CD");
      71          break;
      72        case FUNCTION_VSNPRINTF:
      73          va_start (args, buf);
      74          vsnprintf (arg, 3, "%sCD", args);
      75          TEST_COMPARE_STRING (arg, "CD");
      76          va_end (args);
      77          break;
      78        default:
      79          support_record_failure ();
      80      }
      81  }
      82  
      83  static int
      84  do_test (void)
      85  {
      86    char buf[8];
      87    int i;
      88  
      89    /* For each function in the enum do:
      90         - reset the buffer to the initial state "AB";
      91         - call the function with buffer as source and destination;
      92         - check for the desired behavior.  */
      93    for (i = FUNCTION_FIRST; i < FUNCTION_LAST; i++)
      94      {
      95        strncpy (buf, "AB", 3);
      96        do_one_test (i, buf, buf);
      97      }
      98  
      99    return 0;
     100  }
     101  
     102  #include <support/test-driver.c>