support: Preserve errno in write_message, TEST_VERIFY and other checks

Message ID 20180112073857.83A1141A7FDF7@oldenburg.str.redhat.com
State New
Headers show
Series
  • support: Preserve errno in write_message, TEST_VERIFY and other checks
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Commit Message

Florian Weimer Jan. 12, 2018, 7:38 a.m.
These facilities could clobber errno, which makes it difficult to write
certain checks because a specific order has to be used.

2018-01-12  Florian Weimer  <fweimer@redhat.com>

	* support/write_message.c (write_message): Preserve errno.
	* support/check.c (print_failure): Likewise.
	* support/support_test_verify_impl.c (support_test_verify_impl):
	Likewise.
	* support/support_test_compare_failure.c
	(support_test_compare_failure): Likewise.

Comments

Dmitry V. Levin Jan. 12, 2018, 11:46 a.m. | #1
On Fri, Jan 12, 2018 at 08:38:57AM +0100, Florian Weimer wrote:
> These facilities could clobber errno, which makes it difficult to write
> certain checks because a specific order has to be used.
> 
> 2018-01-12  Florian Weimer  <fweimer@redhat.com>
> 
> 	* support/write_message.c (write_message): Preserve errno.
> 	* support/check.c (print_failure): Likewise.
> 	* support/support_test_verify_impl.c (support_test_verify_impl):
> 	Likewise.
> 	* support/support_test_compare_failure.c
> 	(support_test_compare_failure): Likewise.

Looks good, thanks.

Patch

diff --git a/support/check.c b/support/check.c
index 688ed569ac..78f2b3cde1 100644
--- a/support/check.c
+++ b/support/check.c
@@ -18,6 +18,7 @@ 
 
 #include <support/check.h>
 
+#include <errno.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -26,9 +27,11 @@ 
 static void
 print_failure (const char *file, int line, const char *format, va_list ap)
 {
+  int saved_errno = errno;
   printf ("error: %s:%d: ", file, line);
   vprintf (format, ap);
   puts ("");
+  errno = saved_errno;
 }
 
 int
diff --git a/support/support_test_compare_failure.c b/support/support_test_compare_failure.c
index e5596fd121..8eb51c439d 100644
--- a/support/support_test_compare_failure.c
+++ b/support/support_test_compare_failure.c
@@ -16,6 +16,7 @@ 
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
+#include <errno.h>
 #include <stdio.h>
 #include <support/check.h>
 
@@ -44,6 +45,7 @@  support_test_compare_failure (const char *file, int line,
                               int right_positive,
                               int right_size)
 {
+  int saved_errno = errno;
   support_record_failure ();
   if (left_size != right_size)
     printf ("%s:%d: numeric comparison failure (widths %d and %d)\n",
@@ -52,4 +54,5 @@  support_test_compare_failure (const char *file, int line,
     printf ("%s:%d: numeric comparison failure\n", file, line);
   report (" left", left_expr, left_value, left_positive, left_size);
   report ("right", right_expr, right_value, right_positive, right_size);
+  errno = saved_errno;
 }
diff --git a/support/support_test_verify_impl.c b/support/support_test_verify_impl.c
index 80311a8265..5ff5555a6a 100644
--- a/support/support_test_verify_impl.c
+++ b/support/support_test_verify_impl.c
@@ -18,14 +18,17 @@ 
 
 #include <support/check.h>
 
+#include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 
 void
 support_test_verify_impl (const char *file, int line, const char *expr)
 {
+  int saved_errno = errno;
   support_record_failure ();
   printf ("error: %s:%d: not true: %s\n", file, line, expr);
+  errno = saved_errno;
 }
 
 void
diff --git a/support/write_message.c b/support/write_message.c
index 9d0f267a2f..a3e2f90535 100644
--- a/support/write_message.c
+++ b/support/write_message.c
@@ -18,12 +18,15 @@ 
 
 #include <support/support.h>
 
+#include <errno.h>
 #include <string.h>
 #include <unistd.h>
 
 void
 write_message (const char *message)
 {
+  int saved_errno = errno;
   ssize_t unused __attribute__ ((unused));
   unused = write (STDOUT_FILENO, message, strlen (message));
+  errno = saved_errno;
 }