From 6fe25a08d76736781d597d237a9a9f46a66676bb Mon Sep 17 00:00:00 2001
From: Nicholas Marriott <nicholas.marriott@gmail.com>
Date: Wed, 15 Jul 2009 17:53:15 +0000
Subject: Improved NetBSD current-process detection from Roy Marples.

---
 osdep-netbsd.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 75 insertions(+), 11 deletions(-)

(limited to 'osdep-netbsd.c')

diff --git a/osdep-netbsd.c b/osdep-netbsd.c
index be9cba1b..ce1dffc7 100644
--- a/osdep-netbsd.c
+++ b/osdep-netbsd.c
@@ -1,4 +1,4 @@
-/* $Id: osdep-netbsd.c,v 1.4 2009-06-26 15:54:52 nicm Exp $ */
+/* $Id: osdep-netbsd.c,v 1.5 2009-07-15 17:53:15 nicm Exp $ */
 
 /*
  * Copyright (c) 2009 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -18,14 +18,18 @@
 
 #include <sys/param.h>
 #include <sys/proc.h>
+#include <sys/stat.h>
 #include <sys/sysctl.h>
 
+#include <errno.h>
+#include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 
-#ifndef nitems
-#define nitems(_a) (sizeof((_a)) / sizeof((_a)[0]))
-#endif
+#define is_runnable(p) \
+        ((p)->p_stat == LSRUN || (p)->p_stat == SIDL)
+#define is_stopped(p) \
+        ((p)->p_stat == SSTOP || (p)->p_stat == SZOMB)
 
 char	*osdep_get_name(int, char *);
 
@@ -33,20 +37,80 @@ char *
 osdep_get_name(int fd, __unused char *tty)
 {
 	int		 mib[6];
-	size_t		 len;
-	struct kinfo_proc2 p;
+	struct stat	 sb;
+	size_t		 len, i;
+	struct kinfo_proc2 *buf, *newbuf, *p, *bestp;
+	char		*name;
 
+	if (stat(tty, &sb) == -1)
+		return (NULL);
 	if ((mib[3] = tcgetpgrp(fd)) == -1)
 		return (NULL);
 
+	buf = NULL;
 	len = sizeof(p);
 	mib[0] = CTL_KERN;
 	mib[1] = KERN_PROC2;
-	mib[2] = KERN_PROC_PID;
-	mib[4] = sizeof(p);
-	mib[5] = 1;
-	if (sysctl(mib, nitems(mib), &p, &len, NULL, 0) == -1)
+	mib[2] = KERN_PROC_PGRP;
+	mib[4] = sizeof (*buf);
+	mib[5] = 0;
+
+retry:
+	if (sysctl(mib, __arraycount(mib), NULL, &len, NULL, 0) == -1)
+		return (NULL);
+
+	if ((newbuf = realloc(buf, len * sizeof (*buf))) == NULL) {
+		free(buf);
+		return (NULL);
+	}
+	buf = newbuf;
+
+	mib[5] = len / sizeof(*buf);
+	if (sysctl(mib, __arraycount(mib), buf, &len, NULL, 0) == -1) {
+		if (errno == ENOMEM)
+			goto retry; /* possible infinite loop? */
+		free(buf);
 		return (NULL);
+	}
+
+	bestp = NULL;
+	for (i = 0; i < len / sizeof (*buf); i++) {
+		if (buf[i].p_tdev != sb.st_rdev)
+			continue;
+		p = &buf[i];
+		if (bestp == NULL) {
+			bestp = p;
+			continue;
+		}
+
+		if (is_runnable(p) && !is_runnable(bestp))
+			bestp = p;
+		else if (!is_runnable(p) && is_runnable(bestp))
+			continue;
+
+		if (!is_stopped(p) && is_stopped(bestp))
+			bestp = p;
+		else if (is_stopped(p) && !is_stopped(bestp))
+			continue;
+
+		if (p->p_estcpu > bestp->p_estcpu)
+			bestp = p;
+		else if (p->p_estcpu < bestp->p_estcpu)
+			continue;
+
+		if (p->p_slptime < bestp->p_slptime)
+			bestp = p;
+		else if (p->p_slptime > bestp->p_slptime)
+			continue;
+
+		if (p->p_pid > bestp->p_pid)
+			bestp = p;
+	}
 
-	return (strdup(p.p_comm));
+	name = NULL;
+	if (bestp != NULL)
+		name = strdup(bestp->p_comm);
+	
+	free(buf);
+	return (name);
 }
-- 
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