updated svc, svscan, supervise

01. svc.c: added -W option to wait for service to be down
02. svc.c: added -T timeout option for -w, -W options
03. supervise.c: open supervise/dn fifo in read mode after service goes
    down
04. svscan.c, supervise.c: renamed SERVICEDIR to SCANDIR

daemontools-x/doc/ChangeLog

@@ -12,6 +12,11 @@
 06. svc.c: added -w option to wait for service to be up
 - 21/10/2024
 07. supervise.c: BUG: status file truncated before announce
+- 22/10/2024
+08. svc.c: added -W option to wait for service to be down
+09. svc.c: added -T timeout option for -w, -W options
+10. supervise.c: open supervise/dn fifo in read mode after service goes down
+11. svscan.c, supervise.c: renamed SERVICEDIR to SCANDIR
 
 * Tue Aug 06 2024 12:48:42 +0000 Manvendra Bhangui <daemontools@indimail.org> 1.1.5-1.1%{?dist}
 Release 1.1.5-1.1 Start 05/02/2024 End 06/08/2024

daemontools-x/supervise.8

@@ -105,16 +105,23 @@ secs. Any value above this value will be limited to 60 secs. The wait for
 another service is implemented by opening \fIs\fR/\fIsupervise\fR/\fIup\fR
 in write mode.
 
-\fIsupervise\fR(8) opens \fIs\fR/\fIsupervise\fR/\fIup\fR in write mode
-just after it executes ./run. Hence, if service \fIw\fR is up, write on
-\fIw\fR/\fIsupervise\fR/\fIup\fR, returns immediately. If service \fIw\fR
-is down, the write will block untill \fIw\fR is up and running. If service
+\fIsupervise\fR(8) opens \fIs\fR/\fIsupervise\fR/\fIup\fR in read mode just
+after it executes ./run. Hence, if service \fIw\fR is up, write on
+\fIw\fR/\fIsupervise\fR/\fIup\fR returns immediately. If service \fIw\fR is
+down, the write will block until \fIw\fR is up and running. If service
 \fIw\fR doesn't have \fBsupervise\fR running, \fPsupervise\fR will wait for
 60 seconds before opening the file \fIw\fR/\fIsupervise\fR/\fIup\fR again
-in write mode. The default value of 60 seconds gets overriden by the
+in read mode. The default value of 60 seconds gets overriden by the
 \fBSCANINTERVAL\fR environment variable used by \fBsvscan\fR(8). If service
 \fIw\fR doesn't exist, \fIs\fR/\fIwait\fR will be ignored.
 
+\fIsupervise\fR(8) opens \fIs\fR/\fIsupervise\fR/\fIdn\fR in read mode when
+asked to bring down a service using \fBsvc\fR (-d or -r option). It
+opens this named pipe after issuing the TERM, CONT signal to the service.
+Hence, if service\fIw\fR is down, write on \fIw\fR/\fIsupervise\fR/\fIdn\fR
+returns immediately. if service \fIw\fR is up, the write will block until
+\fIw\fR is down.
+
 \fBsupervise\fR(8) creates the following FIFOs for with O_RDONLY|O_NDELAY
 mode. See open(2) for description of O_RDONLY, O_NDELAY
 
@@ -132,6 +139,11 @@ fifo in O_WRONLY mode, will block until the service \fIs\fR is up. If write
 returns, it means service \fIs\fR has executed \fIs\fR/\fIrun\fR.
 \fBsvc\fR(8) is one such client (-w option) that can be used to check if a
 service is up.
+.IP \[bu] 2
+\fIs\fR/\fIsupervise\fR/\fIdn\fR - clients can open this in write mode to
+test if service \fIs\fR is down. This works like exactly like
+\fIs\fR/\fIsupervise\fR/\fIup\fR. \fBsvc\fR(8) (-W option) can be used to
+check if a service is down.
 
 .PP
 \fBsupervise\fR logs informational, warning and error messages to

daemontools-x/supervise.c

@@ -1,4 +1,4 @@
-/*- $Id: supervise.c,v 1.45 2024-10-21 17:47:39+05:30 Cprogrammer Exp mbhangui $ */
+/*- $Id: supervise.c,v 1.46 2024-10-22 23:02:31+05:30 Cprogrammer Exp mbhangui $ */
 #include <unistd.h>
 #include <fcntl.h>
 #include <sys/types.h>
@@ -31,17 +31,18 @@
 
 static char    *dir;
 static int      selfpipe[2];
-static int      fdlock;
-static int      fdcontrolwrite;
-static int      fdcontrol;
-static int      fdstatus;
-static int      fdok;
-static int      fdup;
+static int      fdlock = -1;
+static int      fdcontrolwrite = -1;
+static int      fdcontrol = -1;
+static int      fdstatus = -1;
+static int      fdok = -1;
+static int      fdup = -1;
+static int      fddn = -1;
 static int      flagexit = 0;
 static int      flagwantxx = 1;
 static int      flagwantup = 1;
 static int      flagpaused;		/*- defined if (pid) */
-static int      fddir;
+static int      fddir = -1;
 static int      logger = 0;
 static int      verbose = 0, silent = 0;
 static char     flagfailed;
@@ -293,6 +294,12 @@ do_wait()
 	 *   opening supervise/up with O_WRONLY should return
 	 * if the service service_name is down
 	 *   opening supervise/up with O_WRONLY should block
+	 *
+	 * supervise/dn is a FIFO
+	 * if the service service_name is running
+	 *   opening supervise/dn with O_WRONLY should block
+	 * if the service service_name is down
+	 *   opening supervise/dn with O_WRONLY should return
 	 */
 	for (i = 0;;) {
 		if ((fd_depend = open(wait_sv_status.s, O_WRONLY)) == -1) {
@@ -422,10 +429,13 @@ trystart(const char *how)
 	}
 	pidchange((childpid = f), 1);
 	announce(0);
-	fifo_make("supervise/up", 0600);
 	if ((fdup = open_read("supervise/up")) == -1) /*- open O_RDONLY|O_NDELAY */
 		strerr_die2sys(111, fatal.s, "read: supervise/up: ");
 	coe(fdup);
+	if (fddn != -1) {
+		close(fddn);
+		fddn = -1;
+	}
 	deepsleep(1);
 }
 
@@ -703,16 +713,19 @@ doit()
 #endif
 					if (!access(*shutdown, F_OK))
 						tryaction(shutdown, childpid, 0, 0); /*- run the shutdown command */
-#ifdef USE_RUNFS
-					if (use_runfs && chdir(dir) == -1) /*- switch back to /run/svscan */
-						strerr_die4sys(111, fatal.s, "unable to switch back to ", dir, ": ");
-#endif
 					siglist[0] = SIGTERM;
 					siglist[1] = SIGCONT;
 					signame[0] = "SIGTERM";
 					signame[1] = "SIGCONT";
 					do_kill(g, siglist, signame);
 					g = flagpaused = 0;
+#ifdef USE_RUNFS
+					if (use_runfs && chdir(dir) == -1) /*- switch back to /run/svscan */
+						strerr_die4sys(111, fatal.s, "unable to switch back to ", dir, ": ");
+#endif
+					if ((fddn = open_read("supervise/dn")) == -1)
+						strerr_die4sys(111, fatal.s, "unable to read ", dir, "/supervise/dn: ");
+					coe(fddn);
 				}
 				announce(0);
 				break;
@@ -1048,7 +1061,7 @@ main(int argc, char **argv)
 	sig_block(sig_child);
 	sig_catch(sig_child, trigger);
 
-	if (!(ptr = env_get("SERVICEDIR"))) {
+	if (!(ptr = env_get("SCANDIR"))) {
 		if (!getcwd(pwdbuf, 255))
 			strerr_die2sys(111, fatal.s, "unable to get current working directory: ");
 		ptr = pwdbuf;
@@ -1110,6 +1123,13 @@ main(int argc, char **argv)
 	if ((fdok = open_read("supervise/ok")) == -1)
 		strerr_die4sys(111, fatal.s, "unable to read ", dir, "/supervise/ok: ");
 	coe(fdok);
+	fifo_make("supervise/up", 0600);
+	fifo_make("supervise/dn", 0600);
+	if (!flagwantup) {
+		if ((fddn = open_read("supervise/dn")) == -1)
+			strerr_die4sys(111, fatal.s, "unable to read ", dir, "/supervise/dn: ");
+		coe(fddn);
+	}
 
 	/*-
 	 * By now we have finished initialization of /run. We
@@ -1138,13 +1158,17 @@ main(int argc, char **argv)
 void
 getversion_supervise_c()
 {
-	const char     *x = "$Id: supervise.c,v 1.45 2024-10-21 17:47:39+05:30 Cprogrammer Exp mbhangui $";
+	const char     *x = "$Id: supervise.c,v 1.46 2024-10-22 23:02:31+05:30 Cprogrammer Exp mbhangui $";
 
 	x++;
 }
 
 /*
  * $Log: supervise.c,v $
+ * Revision 1.46  2024-10-22 23:02:31+05:30  Cprogrammer
+ * renamed SERVICEDIR to SCANDIR for svscan
+ * open supervise/dn after service is brought down
+ *
  * Revision 1.45  2024-10-21 17:47:39+05:30  Cprogrammer
  * BUG: status file truncated before announce
  *

daemontools-x/svc.8

@@ -1,110 +1,83 @@
 .\" vim: tw=75
 .TH svc 8
 .SH NAME
-svc \- controls services monitored by
-.BR supervise(8).
+svc \- controls services monitored by \fBsupervise\fR(8).
+
 .SH SYNOPSIS
 \fBsvc\fR [ \fB\-udopchaitkx\fR ] \fIservices\fR
 
 .SH DESCRIPTION
 \fIservices\fR consists of any number of arguments, each argument naming a
-directory used by \fBsupervise\fR(8).
+directory used by \fBsupervise\fR.
 
 \fBsvc\fR applies all the options to each \fIservice\fR in turn.
 
 .SH OPTIONS
-.TP 4
+.TP 3
 .B \-u
-Up. If the
-.I service
-is not running, start it. If the
-.I service
-stops, restart it. 
+Up. If the \fIservice\fR is not running, start it. If the \fIservice\fR
+stops, restart it.
 
 .TP
 .B \-d
-Down. If the
-.I service
-is running, send it a TERM signal and then a CONT signal. After it stops, do
-not restart it. If the script shutdown exists, run shutdown to terminate the service
+Down. If the \fIservice\fR is running, send it a TERM signal and then a
+CONT signal. After it stops, do not restart it. If the script shutdown
+exists, run shutdown to terminate the service
 
 .TP
 .B \-r
-Restart. If the
-.I service
-is running, send it a term signal, then a CONT signal. After it stops,
-start it.
+Restart. If the \fIservice\fR is running, send it a term signal, then a
+CONT signal. After it stops, start it.
 
 .TP
 .B \-o
-Once. If the
-.I service
-is not running, start it. Do not restart it if it stops. 
+Once. If the \fIservice\fR is not running, start it. Do not restart it if
+it stops.
 
 .TP
 .B \-p
-Pause. Send the
-.I service
-a STOP signal. 
+Pause. Send the \fIservice\fR a STOP signal. 
 
 .TP
 .B \-c
-Continue. Send the
-.I service
-a CONT signal. 
+Continue. Send the \fIservice\fR a CONT signal. 
 
 .TP
 .B \-h
-Hangup. Send the
-.I service
-a HUP signal. 
+Hangup. Send the \fIservice\fR a HUP signal. 
 
 .TP
 .B \-a
-Alarm. Send the
-.I service
-an ALRM signal. 
+Alarm. Send the \fIservice\fR an ALRM signal. 
 
 .TP
 .B \-i
-Interrupt. Send the
-.I service
-an INT signal. 
+Interrupt. Send the \fIservice\fR an INT signal. 
 
 .TP
 .B \-t
-Terminate. Send the
-.I service
-a TERM signal. 
+Terminate. Send the \fIservice\fR a TERM signal. 
 
 .TP
 .B \-q
-Quit. Send the
-.I service
-a QUIT signal. 
+Quit. Send the \fIservice\fR a QUIT signal. 
 
 .TP
 .B \-1 | \-U
-SIGUSR1. Send the
-.I service
-a SIGUSR1 signal. 
+SIGUSR1. Send the \fIservice\fR a SIGUSR1 signal. 
 
 .TP
 .B \-2
-SIGUSR2. Send the
-.I service
-a SIGUSR2 signal. 
+SIGUSR2. Send the \fIservice\fR a SIGUSR2 signal. 
 
 .TP
 .B \-k
-Kill. Send the
-.I service
-a KILL signal. 
+Kill. Send the \fIservice\fR a KILL signal. 
 
 .TP
 .B \-G
-For all options above, the signal will be sent to the entire process group instead of just the pid of
-the \fIservice\fR.
+For all options above, the signal will be sent to the entire process group
+instead of just the pid of the \fIservice\fR.
 
 .TP
 .B \-w
@@ -116,16 +89,32 @@ pipe is opened by \fBsupervise\fR. This option can be used by any program
 to wait for a supervised service. This can also be used by \fBsupervise\fR
 to setup inter-dependencies between services.
 
+.TP
+.B \-W
+Wait. \fBsvc\fR(8) will wait for \fIservice\fR to be down.
+\fBsupervise\fR(8) opens the named pipe \fIservice\fR/\fIdn\fR after
+sending TERM folowed by CONT signal to \fIservice\fR, when svc -d option is
+used. \fBsvc\fR opens this named pipe in O_WRONLY mode in blocking mode,
+thus making \fBsvc\fR wait till the named pipe is opened by
+\fBsupervise\fR. This option can be used by any program to wait for a
+supervised service.
+
+.TP
+.B \-T  \fItimeout
+Use \fItimeout\fR as timeout when waiting for service to be up or down (-w
+or -W options)
+
 .TP
 .B \-x
-Exit.
-.BR supervise (8)
-will exit as soon as the
-.I service
-is down. If you use this option on a stable system, you're doing something
-wrong;
-.BR supervise (8)
-is designed to run forever.
+Exit. \fBsupervise\fR(8) will exit as soon as the \fIservice\fR is down. If
+you use this option on a stable system, you're doing something wrong;
+\fBsupervise\fR is designed to run forever.
+
+.SH RETURN VALUE
+\fBsvc\fR returns 0 if all operations succeeded, 1 if it was not able to
+open \fIservice\fR/\fIsupervise\fR/\fIcontrol\fR, 2 if \fBsupervise\fR for
+service \fIservice\fR is not running and 3 for timeout. The return value
+cannot be used reliably when \fBsvc\fR is passed multiple arguments.
 
 .SH SEE ALSO
 supervise(8),