added chdir/chroot commands to init for mount switching/pivoting

init/builtins.c

@@ -131,6 +131,18 @@ static void service_start_if_not_disabled(struct service *svc)
     }
 }
 
+int do_chdir(int nargs, char **args)
+{
+    chdir(args[1]);
+    return 0;
+}
+
+int do_chroot(int nargs, char **args)
+{
+    chroot(args[1]);
+    return 0;
+}
+
 int do_class_start(int nargs, char **args)
 {
         /* Starting a class does not start services

init/keywords.h

@@ -1,5 +1,7 @@
 
 #ifndef KEYWORD
+int do_chroot(int nargs, char **args);
+int do_chdir(int nargs, char **args);
 int do_class_start(int nargs, char **args);
 int do_class_stop(int nargs, char **args);
 int do_domainname(int nargs, char **args);
@@ -31,6 +33,8 @@ enum {
     K_UNKNOWN,
 #endif
     KEYWORD(capability,  OPTION,  0, 0)
+    KEYWORD(chdir,       COMMAND, 1, do_chdir)
+    KEYWORD(chroot,      COMMAND, 1, do_chroot)
     KEYWORD(class,       OPTION,  0, 0)
     KEYWORD(class_start, COMMAND, 1, do_class_start)
     KEYWORD(class_stop,  COMMAND, 1, do_class_stop)

init/parser.c

@@ -128,6 +128,8 @@ int lookup_keyword(const char *s)
     switch (*s++) {
     case 'c':
         if (!strcmp(s, "apability")) return K_capability;
+        if (!strcmp(s, "hdir")) return K_chdir;
+        if (!strcmp(s, "hroot")) return K_chroot;
         if (!strcmp(s, "lass")) return K_class;
         if (!strcmp(s, "lass_start")) return K_class_start;
         if (!strcmp(s, "lass_stop")) return K_class_stop;

init/readme.txt

@@ -145,12 +145,18 @@ import <filename>
 hostname <name>
    Set the host name.
 
+chdir <directory>
+   Change working directory.
+
 chmod <octal-mode> <path>
    Change file access permissions.
 
 chown <owner> <group> <path>
    Change file owner and group.
 
+chroot <directory>
+  Change process root directory.
+
 class_start <serviceclass>
    Start all services of the specified class if they are
    not already running.