commit 6c3a8a9d868a8deddf0d6dcc785b6d120de90523

Author: Paul Pluzhnikov <ppluzhnikov@kazbek.mtv.corp.google.com>

Date:   Fri Aug 24 18:08:51 2018 -0700

    Fix BZ#23400 (creating temporary files in source tree), and undefined behavior in test.

diff --git a/stdlib/test-bz22786.c b/stdlib/test-bz22786.c

index e7837f98c19fc4bf..d1aa69106ccf6ac5 100644

--- a/stdlib/test-bz22786.c

+++ b/stdlib/test-bz22786.c

@@ -26,28 +26,20 @@

 #include <unistd.h>

 #include <sys/stat.h>

 #include <sys/types.h>

+#include <support/check.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.");

+  const char *lnk = xasprintf ("%s/symlink", dir);

+  const size_t path_len = (size_t) INT_MAX + strlen (lnk) + 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)

-    {

-      printf ("symlink (%s, %s): %m\n", dir, lnk);

-      return EXIT_FAILURE;

-    }

-

-  const size_t path_len = (size_t) INT_MAX + 1;

+  TEST_VERIFY_EXIT (symlink (".", lnk) == 0);

   DIAG_PUSH_NEEDS_COMMENT;

 #if __GNUC_PREREQ (7, 0)

@@ -55,20 +47,14 @@ 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';

+  memset (p, 'a', path_len - (p - path) - 2);

+  p[path_len - (p - path) - 1] = '\0';

   /* This call crashes before the fix for bz22786 on 32-bit platforms.  */

   p = realpath (path, NULL);

@@ -81,7 +67,6 @@ do_test (void)

   /* Cleanup.  */

   unlink (lnk);

-  rmdir (dir);

   return 0;

 }