1 files changed, 63 insertions, 0 deletions
diff --git a/lib/util/openat.c b/lib/util/openat.c
new file mode 100644
index 0000000..b748be9
--- /dev/null
+++ b/lib/util/openat.c
@@ -0,0 +1,63 @@
+/*
+ * SPDX-License-Identifier: ISC
+ *
+ * Copyright (c) 2015, 2019-2020 Todd C. Miller <Todd.Miller@sudo.ws>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/*
+ * This is an open source non-commercial project. Dear PVS-Studio, please check it.
+ * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+ */
+
+#include <config.h>
+
+#include <fcntl.h>
+#include <unistd.h>
+
+#include <sudo_compat.h>
+
+#ifndef HAVE_OPENAT
+int
+sudo_openat(int dfd, const char *path, int flags, mode_t mode)
+{
+    int fd, odfd;
+
+    if (dfd == AT_FDCWD)
+	return open(path, flags, mode);
+
+    /* Save cwd */
+    if ((odfd = open(".", O_RDONLY)) == -1)
+	return -1;
+
+    if (fchdir(dfd) == -1) {
+	close(odfd);
+	return -1;
+    }
+
+    fd = open(path, flags, mode);
+
+    /* Restore cwd */
+    if (fchdir(odfd) == -1) {
+	/* Should not happen */
+	if (fd != -1) {
+	    close(fd);
+	    fd = -1;
+	}
+    }
+    close(odfd);
+
+    return fd;
+}
+#endif /* HAVE_OPENAT */