/***********************************************
 * osdNfs.c
 * 
 * Realize the Linux specified routines for NFS operation
 *
 * Created by: Zheqiao Geng, gengzq@slac.stanford.edu
 * Created on: Aug. 13, 2010
 * Description: Realize the basic function for NFS mount and dismount
 ***********************************************/
#include "osdNfs.h"

/**
 * Global variables
 */
int save_restoreNFSOK    = 1;  /* for Linux, NFS has been mounted before autosave starts */
int save_restoreIoErrors = 0;  /* for accumulate the IO error numbers, when the number larger than threshold, remount NFS */

/**
 * Mount the NFS system (use the RTEMS nfsMount code as reference)
 */
int nfsMount(char *uidhost, char *path, char *mntpoint)
{
    struct stat st;
    int         devl;
    char       *host;          /* host string */
    int         rval = -1;     /* return value */   
    char       *dev  =  0;     /* buffer for the full source path */

    /* check inputs */
    if (!uidhost || !path || !mntpoint) {
        fprintf(stderr,"usage: nfsMount(""[uid.gid@]host"",""path"",""mountpoint"")\n");        
        return -1;
    }

    /* allocate buffer for the whole source */
    if ( !(dev = malloc((devl=strlen(uidhost) + 20 + strlen(path)+1))) ) {
        fprintf(stderr,"nfsMount: out of memory\n");
        return -1;
    }

    /* Try to create the mount point if nonexistent */
    if (stat(mntpoint, &st)) {
        if (ENOENT != errno) {
            perror("nfsMount trying to create mount point - stat failed");
            goto cleanup;
        } else if (mkdir(mntpoint,0777)) {
            perror("nfsMount trying to create mount point");
            goto cleanup;
        }
    }

    /* get the host name or IP address string */
    if ( !(host=strchr(uidhost,UIDSEP)) ) {
        host = uidhost;
    } else {
        host++;
    }

    /* get the full source path */
    if (isdigit(*host)) {
        /* avoid using gethostbyname (for IP address) */
        sprintf(dev,"%s:%s",uidhost,path);
    } else {
        struct hostent *h;

        /* copy the uid part (hostname will be
         * overwritten) */
        strcpy(dev, uidhost);

        /* for string host name, get the IP address */        
        h = gethostbyname(host);

        if ( !h ||
             !inet_ntop( AF_INET,
                         (struct in_addr*)h->h_addr_list[0],
                         dev  + (host - uidhost),
                         devl - (host - uidhost))) {
            fprintf(stderr,"nfsMount: host '%s' not found\n",host);
            goto cleanup;
        }

        /* append ':<path>' */
        strcat(dev,":");
        strcat(dev,path);
    }

    /* mount the NFS */
    printf("Trying to mount %s on %s\n",dev,mntpoint);

    if(mount(dev, mntpoint, "nfs", MS_SYNCHRONOUS, "rsize=8192,wsize=8192")) {
        perror("nfsMount - mount");
        goto cleanup;
    }

    rval = 0;

cleanup:
        free(dev);
        return rval;
}

#define MANAGE_MOUNT 0
int mountFileSystem(char *uidhost, char *addr, char *path, char *mntpoint)
{
#if MANAGE_MOUNT
    /* check the input parameters */
    if (!uidhost || !uidhost[0])   return NFS_INVALID_HOST;
    if (!path || !path[0])         return NFS_INVALID_PATH;
    if (!mntpoint || !mntpoint[0]) return NFS_INVALID_MNTPOINT;
    /* mount the file system */
    if (nfsMount(uidhost, path, mntpoint) == OK) {     /* 0 - succeed; -1 - failed */
        save_restoreNFSOK    = 1;
        save_restoreIoErrors = 0;                      /* clean the counter */
        return OK;
    } else {
        save_restoreNFSOK = 0;
        return ERROR;
    }
#else
    printf("Autosave is not configured to manage the file-system mount point.\n");
	return(OK);  
#endif
}

int dismountFileSystem(char *mntpoint)
{
#if MANAGE_MOUNT

    /* check the input parameters */
    if (!mntpoint || !mntpoint[0]) return NFS_INVALID_MNTPOINT;

    /* unmount the file system */
    save_restoreNFSOK = 0;
	if (umount(mntpoint) == 0) {
		return(OK);
	} else {
		return(ERROR);
	}

#else

    printf("Autosave is not configured to manage the file-system mount point.\n");
	return(OK);

#endif
}