init.c

#include <errno.h>
#include <error.h>
#include <limits.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/mount.h>
#include <sys/types.h>
#include <sys/wait.h>

extern char     **environ;

#define _error error

int     main (int argc, const char * const argv[])
{
        static const char * const       root    = "/dev/md/Volume0_0p3";
        static const char * const       rootfs  = "xfs";
        char                    real_root[PATH_MAX];
        int                     retval  = EXIT_SUCCESS;
        pid_t                   child;

        // mount /sys and /proc
        if (mount("proc", "/proc", "proc", MS_MGC_VAL, NULL) == -1)
        { _error(0, errno, "mount -t proc proc /proc failed with error %d", errno); return errno; }
        if (mount("sysfs", "/sys", "sysfs", MS_MGC_VAL, NULL) == -1)
        { _error(0, errno, "mount -t sysfs sysfs /sys failed with error %d", errno); return errno; }

        _error(0, 0, "Success mounting /proc and /sys\n");

        // run mdadm
        child = vfork();
        if (child == 0) { execl("/sbin/mdadm", "/sbin/mdadm", "--assemble", "--scan", "--auto=mdp", NULL); }
        else
        {
                siginfo_t       info;

                waitid(P_PID, child, &info, WEXITED);
                retval = info.si_status;
        }
        if (retval != EXIT_SUCCESS) { _error(0, 0, "mdadm --assemble --scan --auto=mdp exited with status %d, aborting.\n", retval); return retval; }

        _error(0, 0, "Finished assembling RAID arrays\n");
        sync();

        // mount /
        if (realpath(root, real_root) == NULL)
        { _error(0, errno, "realpath %s failed with error %d", root, errno); return errno; }
        if (mount(real_root, "/mnt", rootfs, MS_MGC_VAL, NULL) == -1)

        _error(0, 0, "Success mounting /\n");
        sync();

        // run init
        retval = execl("/sbin/switch_root", "/sbin/switch_root", "/mnt", "sbin/init", NULL);
        if (retval == -1) { _error(0, errno, "/sbin/switch_root /mnt /sbin/init failed with error %d", errno); return errno; }
        else if (retval != EXIT_SUCCESS) { _error(0, 0, "/sbin/switch_root /mnt /sbin/init exited with status %d, aborting.\n", retval); return retval; }

        return EXIT_SUCCESS;
}