Add support for single (S) user mode from kernel cmdline

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

src/conf.c

@@ -81,6 +81,9 @@ void conf_parse_cmdline(void)
 
 		if (string_compare(tok, "rescue") || string_compare(tok, "recover"))
 			rescue = 1;
+
+		if (string_compare(tok, "single") || string_compare(tok, "S"))
+			single = 1;
 	}
 	fclose(fp);
 
@@ -628,6 +631,10 @@ done:
 	/* Drop record of all .conf changes */
 	drop_changes();
 
+	/* Override configured runlevel, user said 'S' on /proc/cmdline */
+	if (BOOTSTRAP && single)
+		cfglevel = 1;
+
 	/*
 	 * Set host name, from %DEFHOST, *.conf or /etc/hostname.  The
 	 * latter wins, if neither exists we default to "noname"

src/finit.c

@@ -54,6 +54,7 @@ int   runlevel  = 0;		/* Bootstrap 'S' */
 int   cfglevel  = RUNLEVEL;	/* Fallback if no configured runlevel */
 int   prevlevel = -1;
 int   rescue    = 0;		/* rescue mode from kernel cmdline */
+int   single    = 0;		/* single user mode from kernel cmdline */
 char *sdown     = NULL;
 char *network   = NULL;
 char *hostname  = NULL;

src/finit.h

@@ -97,6 +97,7 @@ extern int    runlevel;
 extern int    cfglevel;
 extern int    prevlevel;
 extern int    rescue;
+extern int    single;
 extern char  *rcsd;
 extern char  *sdown;
 extern char  *network;