1 files changed, 115 insertions, 0 deletions
diff --git a/lib/libc/gen/daemon.c b/lib/libc/gen/daemon.c
new file mode 100644
index 000000000000..525c99761aa3
--- /dev/null
+++ b/lib/libc/gen/daemon.c
@@ -0,0 +1,115 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1990, 1993 The Regents of the University of California.
+ * Copyright (c) 2017 Mariusz Zaborski <oshogbo@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include "namespace.h"
+#include <errno.h>
+#include <fcntl.h>
+#include <paths.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <unistd.h>
+#include "un-namespace.h"
+#include "libc_private.h"
+
+int
+daemonfd(int chdirfd, int nullfd)
+{
+	struct sigaction osa, sa;
+	pid_t newgrp;
+	int oerrno;
+	int osa_ok;
+
+	/* A SIGHUP may be thrown when the parent exits below. */
+	sigemptyset(&sa.sa_mask);
+	sa.sa_handler = SIG_IGN;
+	sa.sa_flags = 0;
+	osa_ok = __libc_sigaction(SIGHUP, &sa, &osa);
+
+	switch (fork()) {
+	case -1:
+		return (-1);
+	case 0:
+		break;
+	default:
+		/*
+		 * A fine point:  _exit(0), not exit(0), to avoid triggering
+		 * atexit(3) processing
+		 */
+		_exit(0);
+	}
+
+	newgrp = setsid();
+	oerrno = errno;
+	if (osa_ok != -1)
+		__libc_sigaction(SIGHUP, &osa, NULL);
+
+	if (newgrp == -1) {
+		errno = oerrno;
+		return (-1);
+	}
+
+	if (chdirfd != -1)
+		(void)fchdir(chdirfd);
+
+	if (nullfd != -1) {
+		(void)_dup2(nullfd, STDIN_FILENO);
+		(void)_dup2(nullfd, STDOUT_FILENO);
+		(void)_dup2(nullfd, STDERR_FILENO);
+	}
+	return (0);
+}
+
+int
+daemon(int nochdir, int noclose)
+{
+	int chdirfd, nullfd, ret;
+
+	if (!noclose)
+		nullfd = _open(_PATH_DEVNULL, O_RDWR, 0);
+	else
+		nullfd = -1;
+
+	if (!nochdir)
+		chdirfd = _open("/", O_EXEC);
+	else
+		chdirfd = -1;
+
+	ret = daemonfd(chdirfd, nullfd);
+
+	if (chdirfd != -1)
+		_close(chdirfd);
+
+	if (nullfd > 2)
+		_close(nullfd);
+
+	return (ret);
+}