procstat binary: do not skip pid if either path or osrel sysctls failed

PR:	295893
Reviewed by:	emaste
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D57493

usr.bin/procstat/procstat_bin.c

@@ -35,6 +35,7 @@
 #include <errno.h>
 #include <libprocstat.h>
 #include <limits.h>
+#include <signal.h>
 #include <stdio.h>
 #include <string.h>
 
@@ -50,12 +51,13 @@ procstat_bin(struct procstat *prstat, struct kinfo_proc *kipp)
 		xo_emit("{T:/%5s %-16s %8s %s}\n", "PID", "COMM", "OSREL",
 		    "PATH");
 
-	if (procstat_getpathname(prstat, kipp, pathname, sizeof(pathname)) != 0)
+	if (kill(kipp->ki_pid, 0) == -1)
 		return;
-	if (strlen(pathname) == 0)
+	if (procstat_getpathname(prstat, kipp, pathname, sizeof(pathname))
+	    != 0 || strlen(pathname) == 0)
 		strcpy(pathname, "-");
 	if (procstat_getosrel(prstat, kipp, &osrel) != 0)
-		return;
+		osrel = -1;
 
 	xo_emit("{k:process_id/%5d/%d} ", kipp->ki_pid);
 	xo_emit("{:command/%-16s/%s} ", kipp->ki_comm);