From 39df2f0fa33485ae11bb16b8afcace8c4018fad1 Mon Sep 17 00:00:00 2001
From: Jesse Smith <jsmith@resonatingmedia.com>
Date: Thu, 4 Jul 2019 22:00:47 -0300
Subject: [PATCH] Added -z command line paramter to pidof which tells pidof to
 try to find processes in uninterruptable (D) or zombie (Z) states. This can
 cause pidof to hang, but produces a more complete process list.

---
 doc/Changelog  | 10 ++++++++++
 man/pidof.8    |  7 +++++++
 src/killall5.c | 21 +++++++++++++++++----
 3 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/doc/Changelog b/doc/Changelog
index 67a8c19..bcd1ef7 100644
--- a/doc/Changelog
+++ b/doc/Changelog
@@ -1,3 +1,13 @@
+sysvinit (2.96) released; urgency=low
+
+  [ Jesse Smith ]
+
+    * Added -z command line paramter to pidof which tells pidof to
+      try to find processes in uninterruptable (D) or zombie (Z) states.
+      This can cause pidof to hang, but produces a more complete process
+      list.
+
+
 sysvinit (2.95) released; urgency=low
 
   [ Jesse Smith ]
diff --git a/man/pidof.8 b/man/pidof.8
index 4242d30..ebe5f55 100644
--- a/man/pidof.8
+++ b/man/pidof.8
@@ -24,6 +24,7 @@ pidof -- find the process ID of a running program.
 .RB [ \-c ]
 .RB [ \-n ]
 .RB [ \-x ]
+.RB [ \-z ]
 .RB [ \-o
 .IR omitpid[,omitpid...] ]
 .RB [ \-o
@@ -64,6 +65,10 @@ a status of true or false to indicate whether a matching PID was found.
 .IP \-x
 Scripts too - this causes the program to also return process id's of
 shells running the named scripts.
+.IP \-z
+Try to detect processes which are stuck in uninterruptible (D) or zombie (Z)
+status. Usually these processes are skipped as trying to deal with them can cause
+pidof to hang. 
 .IP "-d \fIsep\fP"
 Tells \fIpidof\fP to use \fIsep\fP as an output separator if more than one PID
 is shown. The default separator is a space.
@@ -92,6 +97,8 @@ so symbolic links to executables will also match.
 .PP
 Zombie processes or processes in disk sleep (states Z and D, respectively)
 are ignored, as attempts to access the stats of these will sometimes fail.
+The \-z flag (see above) tells pidof to try to detect these sleeping and zombie
+processes, at the risk of failing or hanging.
 
 .SH SEE ALSO
 .BR shutdown (8),
diff --git a/src/killall5.c b/src/killall5.c
index 46520e2..8b5cb38 100644
--- a/src/killall5.c
+++ b/src/killall5.c
@@ -135,9 +135,17 @@ NFS *nlist;
 
 /* Did we stop all processes ? */
 int sent_sigstop;
-
 int scripts_too = 0;
 
+/* Should pidof try to list processes in I/O wait (D) and zombie (Z) states? */
+#ifndef FALSE
+#define FALSE 0
+#endif
+#ifndef TRUE
+#define TRUE 1
+#endif
+int list_dz_processes = FALSE;
+
 char *progname;	/* the name of the running program */
 #ifdef __GNUC__
 __attribute__ ((format (printf, 2, 3)))
@@ -598,8 +606,9 @@ int readproc(int do_stat)
 			if (startcode == 0 && endcode == 0)
 				p->kernel = 1;
 			fclose(fp);
-                        if ( (strchr(process_status, 'D') != NULL) ||
-                             (strchr(process_status, 'Z') != NULL) ){
+                        if ( (! list_dz_processes) &&
+                             ( (strchr(process_status, 'D') != NULL) ||
+                               (strchr(process_status, 'Z') != NULL) ) ){
                            /* Ignore zombie processes or processes in
                               disk sleep, as attempts
                               to access the stats of these will
@@ -955,6 +964,7 @@ void pidof_usage(void)
    printf(" -q           Quiet mode. Do not display output\n");
    printf(" -s           Only return one PID\n");
    printf(" -x           Return PIDs of shells running scripts with a matching name\n");
+   printf(" -z           List zombie and I/O waiting processes. May cause pidof to hang.\n");
    printf("\n");
 }
 
@@ -1008,7 +1018,7 @@ int main_pidof(int argc, char **argv)
 	if ((token = getenv("PIDOF_NETFS")) && (strcmp(token,"no") != 0))
 		flags |= PIDOF_NETFS;
 
-	while ((opt = getopt(argc,argv,"qhco:d:sxn")) != EOF) switch (opt) {
+	while ((opt = getopt(argc,argv,"qhco:d:sxzn")) != EOF) switch (opt) {
 		case '?':
 			nsyslog(LOG_ERR,"invalid options on command line!\n");
 			closelog();
@@ -1056,6 +1066,9 @@ int main_pidof(int argc, char **argv)
 		case 'x':
 			scripts_too++;
 			break;
+                case 'z':
+                        list_dz_processes = TRUE;
+                        break;
 		case 'n':
 			flags |= PIDOF_NETFS;
 			break;