build a set of flags for the different enabled subsystems

From: Daniel Lezcano <dlezcano@fr.ibm.com>

When we want to check if a subsystem is enabled, we look at the
presence of a file/directory in the configuration tree files. That
works until we chroot into the rootfs. Some subsystem should be
preferably setup after the chrootfs, making the code simpler and
easier to read. So before setup the different subsystem, I build a
flags set and reuse it later to check if the subsystem is enabled or
not.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

diff --git a/src/lxc/lxc_conf.c b/src/lxc/lxc_conf.c
index 086e5410cbe2aaeb2a42232c01d006bb39e33a46..7253acc9774232c29afd605f5d9753935af889e6 100644 (file)
--- a/src/lxc/lxc_conf.c
+++ b/src/lxc/lxc_conf.c
@@ -1532,41 +1532,86 @@ void lxc_delete_tty(struct lxc_tty_info *tty_info)
        tty_info->nbtty = 0;
 }
 
-int lxc_setup(const char *name, const char *tty, 
+enum { utsname, network, cgroup, fstab, console, tty, rootfs, };
+
+static int conf_is_set(long flags, int subsystem)
+{
+       return flags & (1 << subsystem);
+}
+
+static void conf_set_flag(long *flags, int subsystem)
+{
+       *flags |= 1 << subsystem;
+}
+
+static long make_conf_flagset(const char *name, const char *cons,
+                             const struct lxc_tty_info *tty_info)
+{
+       long flags = 0;
+
+       if (conf_has_utsname(name))
+               conf_set_flag(&flags, utsname);
+
+       if (conf_has_network(name))
+               conf_set_flag(&flags, network);
+
+       if (conf_has_cgroup(name))
+               conf_set_flag(&flags, cgroup);
+
+       if (conf_has_fstab(name))
+               conf_set_flag(&flags, fstab);
+
+       if (conf_has_rootfs(name))
+               conf_set_flag(&flags, rootfs);
+
+       if (tty_info->nbtty)
+               conf_set_flag(&flags, tty);
+
+       if (cons[0])
+               conf_set_flag(&flags, console);
+
+       return flags;
+}
+
+int lxc_setup(const char *name, const char *cons,
              const struct lxc_tty_info *tty_info)
              
 {
-       if (conf_has_utsname(name) && setup_utsname(name)) {
+       /* store the conf flags set otherwise conf_has will not
+        * work after chrooting */
+       long flags = make_conf_flagset(name, cons, tty_info);
+
+       if (conf_is_set(flags, utsname) && setup_utsname(name)) {
                lxc_log_error("failed to setup the utsname for '%s'", name);
                return -LXC_ERROR_SETUP_UTSNAME;
        }
 
-       if (conf_has_network(name) && setup_network(name)) {
+       if (conf_is_set(flags, network) && setup_network(name)) {
                lxc_log_error("failed to setup the network for '%s'", name);
                return -LXC_ERROR_SETUP_NETWORK;
        }
 
-       if (conf_has_cgroup(name) && setup_cgroup(name)) {
+       if (conf_is_set(flags, cgroup) && setup_cgroup(name)) {
                lxc_log_error("failed to setup the cgroups for '%s'", name);
                return -LXC_ERROR_SETUP_CGROUP;
        }
 
-       if (conf_has_fstab(name) && setup_mount(name)) {
+       if (conf_is_set(flags, fstab) && setup_mount(name)) {
                lxc_log_error("failed to setup the mounts for '%s'", name);
                return -LXC_ERROR_SETUP_MOUNT;
        }
 
-       if (tty[0] && setup_console(name, tty)) {
+       if (conf_is_set(flags, console) && setup_console(name, cons)) {
                lxc_log_error("failed to setup the console for '%s'", name);
                return -LXC_ERROR_SETUP_CONSOLE;
        }
 
-       if (tty_info->nbtty && setup_tty(name, tty_info)) {
+       if (conf_is_set(flags, tty) && setup_tty(name, tty_info)) {
                lxc_log_error("failed to setup the ttys for '%s'", name);
                return -LXC_ERROR_SETUP_TTY;
        }
 
-       if (conf_has_rootfs(name) && setup_rootfs(name)) {
+       if (conf_is_set(flags, rootfs) && setup_rootfs(name)) {
                lxc_log_error("failed to set rootfs for '%s'", name);
                return -LXC_ERROR_SETUP_ROOTFS;
        }