Fix BZ 23400 -- stdlib/test-bz22786.c creates temporary files in glibc source tree

  Greetings,

Attached patch fixes BZ 23400, by using standard support for creating
temporary directories.

2018-07-23  Paul Pluzhnikov  <ppluzhnikov@google.com>

        [BZ #23400]
        * stdlib/test-bz22786.c (do_test): Use support_create_temp_directory.
  

On 23/07/2018 13:48, Paul Pluzhnikov wrote:
> Greetings,
> 
> Attached patch fixes BZ 23400, by using standard support for creating
> temporary directories.
> 
> 2018-07-23  Paul Pluzhnikov  <ppluzhnikov@google.com>
> 
>         [BZ #23400]
>         * stdlib/test-bz22786.c (do_test): Use support_create_temp_directory.
> 
> -- Paul Pluzhnikov
> 
> 
> glibc-bz23400-20180721.txt
> 
> 
> diff --git a/stdlib/test-bz22786.c b/stdlib/test-bz22786.c
> index e7837f98c1..f7635c785f 100644
> --- a/stdlib/test-bz22786.c
> +++ b/stdlib/test-bz22786.c
> @@ -26,22 +26,21 @@
>  #include <unistd.h>
>  #include <sys/stat.h>
>  #include <sys/types.h>
> +#include <support/support.h>
> +#include <support/temp_file.h>
>  #include <support/test-driver.h>
>  #include <libc-diag.h>
>  
>  static int
>  do_test (void)
>  {
> -  const char dir[] = "bz22786";
> -  const char lnk[] = "bz22786/symlink";
> +  const char *dir = support_create_temp_directory ("bz22786.");
> +  char *lnk = xmalloc (strlen (dir) + strlen ("/symlink") + 1);
>  
> -  rmdir (dir);
> -  if (mkdir (dir, 0755) != 0 && errno != EEXIST)
> -    {
> -      printf ("mkdir %s: %m\n", dir);
> -      return EXIT_FAILURE;
> -    }
> -  if (symlink (".", lnk) != 0 && errno != EEXIST)
> +  strcpy (lnk, dir);
> +  strcat (lnk, "/symlink");

Maybe just 'char *lnk = xasprintf ("%s/symlink", dir);' instead?

> +
> +  if (symlink (".", lnk) != 0)
>      {
>        printf ("symlink (%s, %s): %m\n", dir, lnk);
>        return EXIT_FAILURE;

Use FAIL_EXIT1 or just TEST_VERIFY_EXIT.


> @@ -55,17 +54,11 @@ do_test (void)
>       allocation to succeed for the test to work.  */
>    DIAG_IGNORE_NEEDS_COMMENT (7, "-Walloc-size-larger-than=");
>  #endif
> -  char *path = malloc (path_len);
> +  char *path = xmalloc (path_len);
>    DIAG_POP_NEEDS_COMMENT;
>  
> -  if (path == NULL)
> -    {
> -      printf ("malloc (%zu): %m\n", path_len);
> -      return EXIT_UNSUPPORTED;
> -    }
> -
> -  /* Construct very long path = "bz22786/symlink/aaaa....."  */
> -  char *p = mempcpy (path, lnk, sizeof (lnk) - 1);
> +  /* Construct very long path = "/tmp/bz22786.XXXX/symlink/aaaa....."  */
> +  char *p = mempcpy (path, lnk, strlen (lnk));
>    *(p++) = '/';
>    memset (p, 'a', path_len - (path - p) - 2);
>    p[path_len - (path - p) - 1] = '\0';

Shouldn't it 'p - path' instead? The subtraction is clearly issuing a
overflow and I think it is not what the test meant here.

> @@ -81,7 +74,6 @@ do_test (void)
>  
>    /* Cleanup.  */
>    unlink (lnk);
> -  rmdir (dir);
>  
>    return 0;
>  }
>