elf: Update audit tests to not depend on stdout

The tst-audit14, tst-audit15 and tst-audit16 tests all have audit
modules that write to stdout; the test reads from stdout to confirm
what was written.  This assumes the stdout is a file which is not the
case when run over ssh.

This patch updates the tests to use a post run cmp command to compare
the output against and .exp file.  This is similar to how many other
tests work and it fixes the stdout limitation.  Also, this means the
test code can be greatly simplified.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

elf/Makefile

@@ -240,6 +240,10 @@ tests-execstack-yes = tst-execstack tst-execstack-needed tst-execstack-prog
 endif
 ifeq ($(have-depaudit),yes)
 tests += tst-audit14 tst-audit15 tst-audit16
+ifeq ($(run-built-tests),yes)
+tests-special += $(objpfx)tst-audit14-cmp.out $(objpfx)tst-audit15-cmp.out \
+		 $(objpfx)tst-audit16-cmp.out
+endif
 endif
 endif
 tests += $(tests-execstack-$(have-z-execstack))
@@ -1492,6 +1496,16 @@ $(objpfx)tst-auditmod17.so: $(objpfx)tst-auditmod17.os
 CFLAGS-.os += $(call elide-stack-protector,.os,tst-auditmod17)
 tst-audit17-ENV = LD_AUDIT=$(objpfx)tst-auditmod17.so
 
+$(objpfx)tst-audit14-cmp.out: tst-audit14.exp $(objpfx)tst-audit14.out
+	cmp $^ > $@; \
+	$(evaluate-test)
+$(objpfx)tst-audit15-cmp.out: tst-audit15.exp $(objpfx)tst-audit15.out
+	cmp $^ > $@; \
+	$(evaluate-test)
+$(objpfx)tst-audit16-cmp.out: tst-audit16.exp $(objpfx)tst-audit16.out
+	cmp $^ > $@; \
+	$(evaluate-test)
+
 # tst-sonamemove links against an older implementation of the library.
 LDFLAGS-tst-sonamemove-linkmod1.so = \
   -Wl,--version-script=tst-sonamemove-linkmod1.map \

elf/tst-audit14.c

@@ -16,30 +16,9 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <stdlib.h>
-#include <string.h>
-#include <support/check.h>
-#include <support/xstdio.h>
-
 static int
 do_test (void)
 {
-  /* Verify what the audit module has written.  This test assumes that
-     standard output has been redirected to a regular file.  */
-  FILE *fp = xfopen ("/dev/stdout", "r");
-
-  char *buffer = NULL;
-  size_t buffer_length = 0;
-  size_t line_length = xgetline (&buffer, &buffer_length, fp);
-  const char *message = "info: tst-auditlogmod-1.so loaded\n";
-  TEST_COMPARE_BLOB (message, strlen (message), buffer, line_length);
-
-  /* No more audit module output.  */
-  line_length = xgetline (&buffer, &buffer_length, fp);
-  TEST_COMPARE_BLOB ("", 0, buffer, line_length);
-
-  free (buffer);
-  xfclose (fp);
   return 0;
 }
 

elf/tst-audit14.exp

@@ -0,0 +1 @@
+info: tst-auditlogmod-1.so loaded

elf/tst-audit15.c

@@ -1,50 +1 @@
-/* Main program with DT_AUDIT and DT_DEPAUDIT.  Two audit modules.
+#include "tst-audit14.c"
-   Copyright (C) 2020-2021 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
-   <https://www.gnu.org/licenses/>.  */
-
-#include <stdlib.h>
-#include <string.h>
-#include <support/check.h>
-#include <support/xstdio.h>
-
-static int
-do_test (void)
-{
-  /* Verify what the audit modules have written.  This test assumes
-     that standard output has been redirected to a regular file.  */
-  FILE *fp = xfopen ("/dev/stdout", "r");
-
-  char *buffer = NULL;
-  size_t buffer_length = 0;
-  size_t line_length = xgetline (&buffer, &buffer_length, fp);
-  const char *message = "info: tst-auditlogmod-1.so loaded\n";
-  TEST_COMPARE_BLOB (message, strlen (message), buffer, line_length);
-
-  line_length = xgetline (&buffer, &buffer_length, fp);
-  message = "info: tst-auditlogmod-2.so loaded\n";
-  TEST_COMPARE_BLOB (message, strlen (message), buffer, line_length);
-
-  /* No more audit module output.  */
-  line_length = xgetline (&buffer, &buffer_length, fp);
-  TEST_COMPARE_BLOB ("", 0, buffer, line_length);
-
-  free (buffer);
-  xfclose (fp);
-  return 0;
-}
-
-#include <support/test-driver.c>

elf/tst-audit15.exp

@@ -0,0 +1,2 @@
+info: tst-auditlogmod-1.so loaded
+info: tst-auditlogmod-2.so loaded

elf/tst-audit16.c

@@ -1,54 +1 @@
-/* Main program with DT_AUDIT and DT_DEPAUDIT.  Three audit modules.
+#include "tst-audit14.c"
-   Copyright (C) 2020-2021 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
-   <https://www.gnu.org/licenses/>.  */
-
-#include <stdlib.h>
-#include <string.h>
-#include <support/check.h>
-#include <support/xstdio.h>
-
-static int
-do_test (void)
-{
-  /* Verify what the audit modules have written.  This test assumes
-     that standard output has been redirected to a regular file.  */
-  FILE *fp = xfopen ("/dev/stdout", "r");
-
-  char *buffer = NULL;
-  size_t buffer_length = 0;
-  size_t line_length = xgetline (&buffer, &buffer_length, fp);
-  const char *message = "info: tst-auditlogmod-1.so loaded\n";
-  TEST_COMPARE_BLOB (message, strlen (message), buffer, line_length);
-
-  line_length = xgetline (&buffer, &buffer_length, fp);
-  message = "info: tst-auditlogmod-2.so loaded\n";
-  TEST_COMPARE_BLOB (message, strlen (message), buffer, line_length);
-
-  line_length = xgetline (&buffer, &buffer_length, fp);
-  message = "info: tst-auditlogmod-3.so loaded\n";
-  TEST_COMPARE_BLOB (message, strlen (message), buffer, line_length);
-
-  /* No more audit module output.  */
-  line_length = xgetline (&buffer, &buffer_length, fp);
-  TEST_COMPARE_BLOB ("", 0, buffer, line_length);
-
-  free (buffer);
-  xfclose (fp);
-  return 0;
-}
-
-#include <support/test-driver.c>

elf/tst-audit16.exp

@@ -0,0 +1,3 @@
+info: tst-auditlogmod-1.so loaded
+info: tst-auditlogmod-2.so loaded
+info: tst-auditlogmod-3.so loaded