--- /dev/null
+/* Testcase for BZ 30932.
+ Copyright (C) 2023 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 <setjmp.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/resource.h>
+#include <unistd.h>
+
+#include <support/check.h>
+#include <support/support.h>
+#include <support/temp_file.h>
+
+jmp_buf chk_fail_buf;
+bool chk_fail_ok;
+
+const char *str2 = "F";
+char buf2[10] = "%s";
+
+static int
+do_test (void)
+{
+ struct rlimit rl;
+ int max_fd = 24;
+
+ if (getrlimit (RLIMIT_NOFILE, &rl) == -1)
+ FAIL_EXIT1 ("getrlimit (RLIMIT_NOFILE): %m");
+
+ max_fd = (rl.rlim_cur < max_fd ? rl.rlim_cur : max_fd);
+ rl.rlim_cur = max_fd;
+
+ if (setrlimit (RLIMIT_NOFILE, &rl) == 1)
+ FAIL_EXIT1 ("setrlimit (RLIMIT_NOFILE): %m");
+
+ /* Exhaust the file descriptor limit with temporary files. */
+ int nfiles = 0;
+ for (; nfiles < max_fd; nfiles++)
+ {
+ int fd = create_temp_file ("tst-sprintf-fortify-rdonly-.", NULL);
+ if (fd == -1)
+ {
+ if (errno != EMFILE)
+ FAIL_EXIT1 ("create_temp_file: %m");
+ break;
+ }
+ }
+ TEST_VERIFY_EXIT (nfiles != 0);
+
+ /* When the format string is writable and contains %n,
+ with -D_FORTIFY_SOURCE=2 it causes __chk_fail. However, if libc can not
+ open procfs to check if the input format string in within a writable
+ memory segment, the fortify version can not perform the check. */
+ char buf[128];
+ int n1;
+ int n2;
+
+ strcpy (buf2 + 2, "%n%s%n");
+ if (sprintf (buf, buf2, str2, &n1, str2, &n2) != 2
+ || n1 != 1 || n2 != 2)
+ FAIL_EXIT1 ("sprintf failed: %s %d %d", buf, n1, n2);
+
+ return 0;
+}
+
+#include <support/test-driver.c>