Add-additional-functions-to-dtach.patch

From: Jason Wessel <jason.wessel@windriver.com>
Date: Sun, 17 Jul 2016 12:07:33 -0400
Subject: [PATCH] Add additional functions to dtach

-C     Do not force the client to clear the screen on connect
-q     Quiet exit from client when running commands
-w     Allow the server to wait for a client to connect
-W <#> Terminate the server if a client doesn't connect in # seconds

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
---
 attach.c |  8 +++++---
 dtach.h  |  1 +
 main.c   | 35 +++++++++++++++++++++++++++++++++--
 master.c | 24 ++++++++++++++++++++++++
 4 files changed, 63 insertions(+), 5 deletions(-)

diff --git a/attach.c b/attach.c
index 034e277..a43268c 100644
--- a/attach.c
+++ b/attach.c
@@ -215,7 +215,8 @@ attach_main(int noerror)
 	tcsetattr(0, TCSADRAIN, &cur_term);
 
 	/* Clear the screen. This assumes VT100. */
-	write(1, "\33[H\33[J", 6);
+	if (do_clear)
+		write(1, "\33[H\33[J", 6);
 
 	/* Tell the master that we want to attach. */
 	memset(&pkt, 0, sizeof(struct packet));
@@ -250,8 +251,9 @@ attach_main(int noerror)
 
 			if (len == 0)
 			{
-				printf(EOS "\r\n[EOF - dtach terminating]"
-					"\r\n");
+				if (!quiet_flag)
+					printf(EOS "\r\n[EOF - dtach terminating]"
+					       "\r\n");
 				exit(0);
 			}
 			else if (len < 0)
diff --git a/dtach.h b/dtach.h
index d0ba87e..e369321 100644
--- a/dtach.h
+++ b/dtach.h
@@ -83,6 +83,7 @@
 
 extern char *progname, *sockname;
 extern int detach_char, no_suspend, redraw_method;
+extern int quiet_flag, do_clear, alarm_time;
 extern struct termios orig_term;
 extern int dont_have_tty;
 
diff --git a/main.c b/main.c
index 5fd7bcc..eb3a6a8 100644
--- a/main.c
+++ b/main.c
@@ -37,6 +37,12 @@ int detach_char = '\\' - 64;
 int no_suspend;
 /* The default redraw method. Initially set to unspecified. */
 int redraw_method = REDRAW_UNSPEC;
+/* Clear screen on attach */
+int do_clear = 1;
+/* Quiet on exit */
+int quiet_flag = 0;
+/* Timeout for client connect */
+int alarm_time = 0;
 
 /*
 ** The original terminal settings. Shared between the master and attach
@@ -70,14 +76,18 @@ usage()
 		"  -p\t\tCopy the contents of standard input to the specified\n"
 		"\t\t  socket.\n"
 		"Options:\n"
+		"  -C\t\tDo not clear screen on attach.\n"
 		"  -e <char>\tSet the detach character to <char>, defaults "
 		"to ^\\.\n"
 		"  -E\t\tDisable the detach character.\n"
+		"  -q\t\tQuiet on exit from client.\n"
 		"  -r <method>\tSet the redraw method to <method>. The "
 		"valid methods are:\n"
 		"\t\t     none: Don't redraw at all.\n"
 		"\t\t   ctrl_l: Send a Ctrl L character to the program.\n"
 		"\t\t    winch: Send a WINCH signal to the program.\n"
+		"  -w\t\tWait for client to connect before process exec.\n"
+		"  -W <#>\tServer exit after # seconds.\n"
 		"  -z\t\tDisable processing of the suspend key.\n"
 		"\nReport any bugs to <" PACKAGE_BUGREPORT ">.\n",
 		PACKAGE_VERSION, __DATE__, __TIME__);
@@ -88,6 +98,7 @@ int
 main(int argc, char **argv)
 {
 	int mode = 0;
+	int connect_wait = 0;
 
 	/* Save the program name */
 	progname = argv[0];
@@ -157,6 +168,12 @@ main(int argc, char **argv)
 		{
 			if (*p == 'E')
 				detach_char = -1;
+			else if (*p == 'C')
+				do_clear = 0;
+			else if (*p == 'q')
+				quiet_flag = 1;
+			else if (*p == 'w')
+				connect_wait = 1;
 			else if (*p == 'z')
 				no_suspend = 1;
 			else if (*p == 'e')
@@ -208,6 +225,20 @@ main(int argc, char **argv)
 				}
 				break;
 			}
+			else if (*p == 'W')
+			{
+				++argv; --argc;
+				if (argc < 1)
+				{
+					printf("%s: No time specified.\n",
+					       progname);
+					printf("Try '%s --help' for more "
+						"information.\n", progname);
+					return 1;
+				}
+				alarm_time = atoi(argv[0]);
+				break;
+			}
 			else
 			{
 				printf("%s: Invalid option '-%c'\n",
@@ -255,9 +286,9 @@ main(int argc, char **argv)
 		return attach_main(0);
 	}
 	else if (mode == 'n')
-		return master_main(argv, 0, 0);
+		return master_main(argv, connect_wait, 0);
 	else if (mode == 'N')
-		return master_main(argv, 0, 1);
+		return master_main(argv, connect_wait, 1);
 	else if (mode == 'c')
 	{
 		if (master_main(argv, 1, 0) != 0)
diff --git a/master.c b/master.c
index b136f03..774cfe6 100644
--- a/master.c
+++ b/master.c
@@ -339,6 +339,10 @@ control_activity(int s)
 		close(fd);
 		return;
 	}
+	if (alarm_time) {
+		alarm(0);
+		alarm_time = 0;
+	}
 
 	/* Link it in. */
 	p = malloc(sizeof(struct client));
@@ -430,6 +434,17 @@ client_activity(struct client *p)
 	}
 }
 
+static int dup_stdout = -1;
+
+/* Alarm handler for timeout waiting on client connect */
+static void
+	alarm_handler(int sig)
+{
+	if (!quiet_flag && dup_stdout >= 0)
+		dprintf(dup_stdout, "EXIT: Client connect timeout\n");
+	exit(sig);
+}
+
 /* The master process - It watches over the pty process and the attached */
 /* clients. */
 static void
@@ -475,6 +490,15 @@ master_process(int s, char **argv, int waitattach, int statusfd)
 	if (statusfd != -1)
 		close(statusfd);
 
+
+	if (alarm_time)
+	{
+		/* Duplicate stdout for later output use */
+		dup_stdout = dup(1);
+		signal(SIGALRM, alarm_handler);
+		alarm(alarm_time);
+	}
+
 	/* Make sure stdin/stdout/stderr point to /dev/null. We are now a
 	** daemon. */
 	nullfd = open("/dev/null", O_RDWR);
-- 
2.5.0