From 0cc9b20c15460213e488bf5e70963b941482f628 Mon Sep 17 00:00:00 2001
From: William Harrington <kb0iic@berzerkula.org>
Date: Tue, 14 Jan 2025 16:06:02 -0600
Subject: Add source.

---
 sdk/proc/pdetach.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 sdk/proc/pdetach.c

(limited to 'sdk/proc/pdetach.c')

diff --git a/sdk/proc/pdetach.c b/sdk/proc/pdetach.c
new file mode 100644
index 0000000..40814e4
--- /dev/null
+++ b/sdk/proc/pdetach.c
@@ -0,0 +1,78 @@
+/*
+ * Deamon-ify a user process; detach from controlling terminal and parent.
+ * $Id: daemon.c 1.2 Wed, 19 Mar 1997 12:44:53 -0500 dyfet $
+ * Copyright (c) 1997 by Tycho Softworks.
+ * For conditions on distribution and reuse see product license.
+ *
+ * Abstract:
+ *	Daemon processes are commonly used in UNIX to build server
+ *	applications.  This module captures the essense of functionality
+ *	required to make a process into a daemon within a single function
+ *	call.
+ *
+ * Functions:
+ *	daemon() - convert user process into a daemon.
+ */
+
+#include <proc/process.h>
+#include <std/signal.h>
+
+/* Daemonify a user process under UNIX.
+ *
+ * Abstract:
+ *	In UNIX, a user process becomes a daemon by detaching itself from
+ *	it's parent process and establishes it's own process group.  A
+ *	daemon may also detach itself from it's controlling terminal.
+ *	This is usually accomplished through fork().
+ *
+ * Paramaters:
+ *	flag - specifies daemon mode of operation:
+ *		D_KEEPALL 	keeps all files open.
+ *		D_KEEPSTDIO	keeps stdio (stdin, stdout, stderr) open.
+ *		D_KEEPNONIO	detaches from stdio, keeps other files.
+ *		D_KEEPNONE	closes all open files.
+ *
+ * Returns:
+ *	New pid of user process running as a daemon.
+ *
+ * Exceptions:
+ *	Any failure terminates the process.  No error message is possible
+ *	since the process may already be detached from user I/O.
+ */
+
+pid_t	pdetach(int flag)
+{
+	pid_t	pid;
+	int	max = OPEN_MAX;
+	int	i;
+
+	signal(SIGHUP, SIG_IGN);
+
+	i = 0;
+	if(flag == D_KEEPSTDIO)
+		i = 3;
+
+	if(flag == D_KEEPNONIO)
+		max = 3;
+		
+	while((i < max) && (flag != D_KEEPALL))
+		close(i++);
+
+	pid = fork();
+	if(pid < 0)
+		return pid;
+
+	if(pid > 0)
+		exit(EX_OK);
+
+	setsid();
+	setpgid(0, getpid());
+	pid = fork();
+	if(pid < 0)
+		return pid;
+
+	if(pid > 0)
+		exit(EX_OK);
+	
+	return	getpid();
+}
-- 
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