1 files changed, 76 insertions, 0 deletions
diff --git a/support/support_run_diff.c b/support/support_run_diff.c
new file mode 100644
index 0000000000..f5155de727
--- /dev/null
+++ b/support/support_run_diff.c
@@ -0,0 +1,76 @@
+/* Invoke the system diff tool to compare two strings.
+   Copyright (C) 2016-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <support/run_diff.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <support/check.h>
+#include <support/support.h>
+#include <support/temp_file.h>
+#include <support/xunistd.h>
+#include <sys/wait.h>
+
+static char *
+write_to_temp_file (const char *prefix, const char *str)
+{
+  char *template = xasprintf ("run_diff-%s", prefix);
+  char *name = NULL;
+  int fd = create_temp_file (template, &name);
+  TEST_VERIFY_EXIT (fd >= 0);
+  free (template);
+  xwrite (fd, str, strlen (str));
+  xclose (fd);
+  return name;
+}
+
+void
+support_run_diff (const char *left_label, const char *left,
+                  const char *right_label, const char *right)
+{
+  /* Ensure that the diff command output is ordered properly with
+     standard output.  */
+  TEST_VERIFY_EXIT (fflush (stdout) == 0);
+
+  char *left_path = write_to_temp_file ("left-diff", left);
+  char *right_path = write_to_temp_file ("right-diff", right);
+
+  pid_t pid = xfork ();
+  if (pid == 0)
+    {
+      execlp ("diff", "diff", "-u",
+              "--label", left_label, "--label", right_label,
+              "--", left_path, right_path,
+              NULL);
+      _exit (17);
+    }
+  else
+    {
+      int status;
+      xwaitpid (pid, &status, 0);
+      if (!WIFEXITED (status) || WEXITSTATUS (status) != 1)
+        printf ("warning: could not run diff, exit status: %d\n"
+                "*** %s ***\n%s\n"
+                "*** %s ***\n%s\n",
+                status, left_label, left, right_label, right);
+    }
+
+  free (right_path);
+  free (left_path);
+}