Added new runlevel log code which saves (and reads) the current runlevel

from /var/run/runlevel. Added test code to runlevel.c to confirm it works.

Will use this to save/restore runlevel on systems where utmp is not
available.

src/Makefile

@@ -125,7 +125,7 @@ utmpdump:	LDLIBS += $(STATIC)
 utmpdump:	utmpdump.o
 
 runlevel:	LDLIBS += $(STATIC)
-runlevel:	runlevel.o
+runlevel:	runlevel.o runlevellog.o
 
 sulogin:	LDLIBS += $(SULOGINLIBS) $(STATIC)
 sulogin:	sulogin.o consoles.o
@@ -145,6 +145,8 @@ fstab-decode:	fstab-decode.o
 sulogin.o:	CPPFLAGS += $(SELINUX_DEF)
 sulogin.o:	sulogin.c 
 
+runlevellog.o:	runlevellog.h runlevellog.c paths.h
+
 init.o:		CPPFLAGS += $(SELINUX_DEF)
 init.o:		init.c init.h initreq.h paths.h reboot.h set.h
 

src/paths.h

@@ -37,6 +37,7 @@
 #define INITSCRIPT	"/etc/initscript"	/* Initscript. */
 #define PWRSTAT_OLD	"/etc/powerstatus"	/* COMPAT: SIGPWR reason (OK/BAD) */
 #define PWRSTAT		"/var/run/powerstatus"	/* COMPAT: SIGPWR reason (OK/BAD) */
+#define RUNLEVEL_LOG    "/var/run/runlevel"     /* neutral place to store run level */
 
 #if 0
 #define INITLVL		"/etc/initrunlvl"	/* COMPAT: New runlevel */

src/runlevel.c

@@ -25,6 +25,7 @@
 #include <utmp.h>
 #include <time.h>
 #include <stdlib.h>
+#include "runlevellog.h"
 
 int main(argc, argv)
 int argc;
@@ -32,6 +33,7 @@ char **argv;
 {
   struct utmp *ut;
   char prev;
+  int status, runlevel;
 
   if (argc > 1) utmpname(argv[1]);
 
@@ -45,9 +47,15 @@ char **argv;
 		exit(0);
 	}
   }
-  
-  printf("unknown\n");
   endutent();
+  
+  status = Read_Runlevel_Log(&runlevel);
+  if (status)
+  {
+     printf("%c\n", runlevel);
+     return 0;
+  }
+  printf("Unknown.\n");
   return(1);
 }
 

src/runlevellog.c

@@ -0,0 +1,71 @@
+/*
+ * runlevellog  - Saves and restores runlevel from distor-neutral location.
+ *
+ *
+ *              This file is part of the sysvinit suite,
+ *              Copyright (C) 2018 Jesse Smith
+ *
+ *              This program is free software; you can redistribute it and/or modify
+ *              it under the terms of the GNU General Public License as published by
+ *              the Free Software Foundation; version 2 of the License.
+ *
+ *              This program is distributed in the hope that it will be useful,
+ *              but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *              MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *              GNU General Public License for more details.
+ *
+ *              You should have received a copy of the GNU General Public License
+ *              along with this program; if not, write to the Free Software
+ *              Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdio.h>
+#include "paths.h"
+#include "runlevellog.h"
+
+/*
+Write the current runlevel to its log file.
+The function returns TRUE on success and FALSE
+on failure.
+*/
+int Write_Runlevel_Log(int new_runlevel)
+{
+   FILE *log_file;
+   int status;
+
+   log_file = fopen(RUNLEVEL_LOG, "w");
+   if (! log_file)
+      return FALSE;
+
+   status = fprintf(log_file, "%c", new_runlevel);
+   fclose(log_file);
+   if (status < 1)
+      return FALSE;
+   return TRUE;
+}   // end of writing to log function
+
+
+/*
+This function reads the last runlevel from the log file.
+The function stores the read value at the addressed passed
+into the function (aka runlevel). The function returns
+TRUE on success and FALSE on failure.
+*/
+int Read_Runlevel_Log(int *runlevel)
+{
+   FILE *log_file;
+   int status;
+
+   log_file = fopen(RUNLEVEL_LOG, "r");
+   if (! log_file)
+     return FALSE;
+
+   status = fscanf(log_file, "%c", runlevel);
+   fclose(log_file);
+   if (status == EOF)
+      return FALSE;
+   return TRUE;
+
+}   // end of reading from log function
+
+

src/runlevellog.h

@@ -0,0 +1,36 @@
+/*
+ * runlevellog  - Saves and restores runlevel from distor-neutral location.
+ *
+ *
+ *              This file is part of the sysvinit suite,
+ *              Copyright (C) 2018 Jesse Smith
+ *
+ *              This program is free software; you can redistribute it and/or modify
+ *              it under the terms of the GNU General Public License as published by
+ *              the Free Software Foundation; version 2 of the License.
+ *
+ *              This program is distributed in the hope that it will be useful,
+ *              but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *              MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *              GNU General Public License for more details.
+ *
+ *              You should have received a copy of the GNU General Public License
+ *              along with this program; if not, write to the Free Software
+ *              Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef RUNLEVEL_LOG_HEADER__
+#define RUNLEVEL_LOG_HEADER__
+
+#ifndef TRUE
+#define TRUE 1
+#endif
+#ifndef FALSE
+#define FALSE 0
+#endif
+
+int Write_Runlevel_Log(int new_runlevel);
+int Read_Runlevel_Log(int *runlevel);
+
+#endif
+