stdlib: Test using setenv with updated environ [BZ #32588]

Add a test for setenv with updated environ.  Verify that BZ #32588 is
fixed.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Florian Weimer <fweimer@redhat.com>

2 files changed, 37 insertions, 0 deletions

diff --git a/stdlib/Makefile b/stdlib/Makefile
index c8b96b3..1c4fa23 100644
--- a/stdlib/Makefile
+++ b/stdlib/Makefile
@@ -320,6 +320,7 @@ tests := \
   tst-setcontext9 \
   tst-setcontext10 \
   tst-setcontext11 \
+  tst-setenv-environ \
   tst-stdbit-Wconversion \
   tst-stdbit-builtins \
   tst-stdc_bit_ceil \
diff --git a/stdlib/tst-setenv-environ.c b/stdlib/tst-setenv-environ.c
new file mode 100644
index 0000000..02fcef9
--- /dev/null
+++ b/stdlib/tst-setenv-environ.c
@@ -0,0 +1,36 @@
+/* Test using setenv with updated environ.
+   Copyright (C) 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 <stdlib.h>
+#include <support/check.h>
+
+extern char **environ;
+
+int
+do_test (void)
+{
+  char *valp;
+  static char *dummy_environ[] = { NULL };
+  environ = dummy_environ;
+  setenv ("A", "1", 0);
+  valp = getenv ("A");
+  TEST_VERIFY_EXIT (valp[0] == '1' && valp[1] == '\0');
+  return 0;
+}
+
+#include <support/test-driver.c>