#include <stdio.h>
#include <stdlib.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include <getopt.h>
#include <signal.h>

/////////////////////////////////////////////////////////////////////////////////////////
/*FLAGS FROM KERNEL*/

//#define MS_RDONLY	 1	/* Mount read-only */
//#define MS_NOSUID	 2	/* Ignore suid and sgid bits */
//#define MS_NODEV	 4	/* Disallow access to device special files */
//#define MS_NOEXEC	 8	/* Disallow program execution */
//#define MS_SYNCHRONOUS	16	/* Writes are synced at once */
//#define MS_REMOUNT	32	/* Alter flags of a mounted FS */
//#define MS_MANDLOCK	64	/* Allow mandatory locks on an FS */
//#define MS_DIRSYNC	128	/* Directory modifications are synchronous */
//#define MS_NOATIME	1024	/* Do not update access times. */
//#define MS_NODIRATIME	2048	/* Do not update directory access times */
//#define MS_BIND		4096
//#define MS_MOVE		8192
//#define MS_REC		16384
//#define MS_VERBOSE	32768	/* War is peace. Verbosity is silence.
//				   MS_VERBOSE is deprecated. */
//#define MS_SILENT	32768
//#define MS_POSIXACL	(1<<16)	/* VFS does not apply the umask */
//#define MS_UNBINDABLE	(1<<17)	/* change to unbindable */
//#define MS_PRIVATE	(1<<18)	/* change to private */
//#define MS_SLAVE	(1<<19)	/* change to slave */
//#define MS_SHARED	(1<<20)	/* change to shared */
//#define MS_RELATIME	(1<<21)	/* Update atime relative to mtime/ctime. */
//#define MS_KERNMOUNT	(1<<22) /* this is a kern_mount call */
//#define MS_I_VERSION	(1<<23) /* Update inode I_version field */
//#define MS_STRICTATIME	(1<<24) /* Always perform atime updates */
//#define MS_LAZYTIME	(1<<25) /* Update the on-disk [acm]times lazily */

#define STRUCT_LEN(VAR,STRUCT) ((sizeof(VAR)/sizeof(STRUCT))-1)

typedef struct vfs_option_params {
    char *val;
    char *descr;
} vfs_option_params;

vfs_option_params vfs_options_proc_params_hidepid[] = {
    {"0","Everybody may access all proc"},
    {"1","User can access only their own proc, not other /proc/[pid]"},
    {"2","As for mode 1, extra hides pid directories of others"},
    {NULL,NULL},
};

vfs_option_params vfs_options_proc_params_gid[] = {
    {"gid","usergroup who sees /proc in mode 0"},
    {NULL,NULL},
};

typedef struct vfs_options 
{
    char *options;
    char *description;
    vfs_option_params **params;
} vfs_options;

vfs_options vfs_options_proc[] =
{
    {"hidepid=\%u" ,"",                                     &vfs_options_proc_params_hidepid},
    {"gid=\%u"     ,"user group that can access process",   &vfs_options_proc_params_gid},
    {NULL,NULL,NULL}
};

static const struct vfs {
    char *name;
    long flags;
    char *mountpoint;
    vfs_options *options;
} vfstab[] = {
    {"devtmpfs",  0, "/Device",  NULL},
    {"mqueue",    0, "/MQueue/", NULL},
    {"proc",      0, "/Process", &vfs_options_proc},
    {"tmpfs",     0, "/Ram",     NULL},
    {"sysfs",     0, "/System",  NULL},
    {"ext4",      0, NULL,       NULL},
    {"vfat",      0, NULL,       NULL},
    {NULL,        0, NULL,       NULL},
};

typedef struct {
    char *f_device;
    char *f_type;
    char *f_dir;
    char *f_flags;//g_params.f_output = 1;
    char *f_options;
    int   f_verbose;
    int   f_helper;
} mount_params;

static mount_params g_params;

void helper(char *progname)
{
    printf("Usage: %s [OPTS]\n\n"
        "Version: 0.0.1 \n"
        "-d device to mount\n"
        "-t filesystem type\n"
        "-d mount directory\n"
        "-f mount flags\n"
        "-o mount fs options\n"
        "-v verbose output\n"
        "-h help options\n"
        "-a helper for filetype options\n"
        "\n"
        , progname);
}

void sig_handler(int signo)
{
    switch(signo)
    {
        case SIGINT:
            //printf("Catch SIGINT Exit\n");
            //if (g_params.f_output)
            //{
            //    printf("Data in %d bytes Data out %d bytes",g_stats.cnt_in,g_stats.cnt_out);
            //}
        default:
            printf("Unknown signal %d\n",signo);
    }
    exit(0);
}

int smount(
    const char *source, 
    const char *target,
    const char *filesystemtype,
    unsigned long mountflags,
    const void *data)
{

    return 0;
}

int main(int argc, char **argv)
{
    int c;
    int i;

    printf("One big real mount\n");

    if (signal(SIGINT,sig_handler) == SIG_ERR)
    {
        printf("cannot register signal handler\n");
        exit(1);
    }
    
    //process arguments
    while ((c = getopt(argc, argv, "a")) != -1)
    {
        switch (c)
        {
            case 'a':
                //g_params.f_output = 1;
                g_params.f_helper = 1;
                break;
            
            default:
                helper(argv[0]);
                exit(1);
        }
    }

    if (1 == g_params.f_helper)
    {
        for (i=0;i<STRUCT_LEN(vfstab,struct vfs);i++)
        {
            printf("%s %s\n",vfstab[i].name,vfstab[i].mountpoint);
        }
    }


    return 0;
}