1 files changed, 51 insertions, 0 deletions
diff --git a/libio/tst-asprintf-null.c b/libio/tst-asprintf-null.c
new file mode 100644
index 0000000..0b367d7
--- /dev/null
+++ b/libio/tst-asprintf-null.c
@@ -0,0 +1,51 @@
+/* Test that asprintf sets the buffer pointer to NULL on failure.
+   Copyright (C) 2024-2025 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 <errno.h>
+#include <stdio.h>
+#include <support/check.h>
+#include <sys/resource.h>
+
+static int
+do_test (void)
+{
+  static const char sentinel[] = "sentinel";
+  char *buf = (char *) sentinel;
+  {
+    /* Avoid -Wformat-overflow warning.  */
+    const char *volatile format = "%2000000000d %2000000000d";
+    TEST_COMPARE (asprintf (&buf, format, 1, 2), -1);
+  }
+  if (errno != ENOMEM)
+    TEST_COMPARE (errno, EOVERFLOW);
+  TEST_VERIFY (buf == NULL);
+
+  /* Force ENOMEM in the test below.  */
+  struct rlimit rl;
+  TEST_COMPARE (getrlimit (RLIMIT_AS, &rl), 0);
+  rl.rlim_cur = 10 * 1024 * 1024;
+  TEST_COMPARE (setrlimit (RLIMIT_AS, &rl), 0);
+
+  buf = (char *) sentinel;
+  TEST_COMPARE (asprintf (&buf, "%20000000d", 1), -1);
+  TEST_COMPARE (errno, ENOMEM);
+  TEST_VERIFY (buf == NULL);
+  return 0;
+}
+
+#include <support/test-driver.c>