path: root/src/common/unionfs.c

#include <string.h>
#include <stdlib.h>
#include <dirent.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <glib-2.0/glib.h>
#include "common/defs.h"
#include "common/unionfs.h"

boolean g_debug;

extern vtw_path m_path;
extern vtw_path t_path;

void
retrieve_data(char* rel_data_path, GNode *node, char* root, NODE_OPERATION op);

void
apply_priority(GNode *root_node);

void
set_path(char *path, boolean config);

struct VyattaNode*
copy_vyatta_node(struct VyattaNode* vn);

void
get_term_data_values(GNode *node);

void
dlist_test_func(GQuark key_id,gpointer data,gpointer user_data);

void
match_priority_node(GNode *node, gchar** tok_str, int pri);

GNode*
insert_sibling_in_order(GNode *parent, GNode *child);

static gboolean
copy_func(GNode *node, gpointer data);

static gboolean
delete_func(GNode *node, gpointer data);

/**
 *
 *
 Data is stored on the path:

 /opt/vyatta/config/tmp/new_config_5425/system/login/user/foo/authentication/plaintext-password

 Config is stored along this path:

 /opt/vyatta/config/template/vyatta-cfg/system/login/user/node.tag/authentication/plaintext-password

 1) Need to split out relative path

 2) if node is *MULTI* then the path value is the actual value

 3) For the config copy the pointer from an existing config value for each multinode
<Need to figure out how this is going to happen>

This should allow a combined data/config tree

 *
 *
 *
 **/
char*
get_config_path(GNode *node)
{
  char *buf;
  buf = malloc(MAX_LENGTH_DIR_PATH*sizeof(char));
  buf[0] = '/';
  buf[1] = '\0';
  if (node == NULL) {
    return NULL;
  }

  GNode *n = node;
  while (G_NODE_IS_ROOT(n) != TRUE) {
    struct VyattaNode *d = (struct VyattaNode*)n->data;
    if (d == NULL) {
      if (g_debug) {
	printf("unionfs::get_config_path(): data ptr is null\n");
      }
      return NULL;
    }

    //if not found, mark current node as multinode
    if (d->_data._name != NULL) {
      char tmp[MAX_LENGTH_DIR_PATH];
      strcpy(tmp,buf);

      //need to check the configuration location for the existance of this node to determine if it's a multi
      if (G_NODE_IS_ROOT(n->parent) != TRUE && 
	  ((struct VyattaNode*)(n->parent->data))->_config._multi == TRUE) {
	sprintf(buf,"node.tag/%s",tmp);
      }
      else {
	sprintf(buf,"%s/%s",d->_data._name,tmp);
      }
    }
    n = n->parent;
  }
  return buf;
}


/**
 * Recurse from node identified as deleted
 **/
void
retrieve_delete_data(char* rel_data_path, GNode *node)
{
  //switch root

  return;
}

/**
 *
 **/
void
retrieve_data(char* rel_data_path, GNode *node, char* root, NODE_OPERATION op)
{
  boolean final_node = FALSE;

  if (node == NULL) {
    return;
  }

  char *tmp = root;//get_cdirp();
  char full_data_path[sizeof(char)*MAX_LENGTH_DIR_PATH];
  strcpy(full_data_path,tmp);
  if (rel_data_path != NULL) {
    strcat(full_data_path,rel_data_path);
  }

  if (g_debug) {
    printf("unionfs::retrieve_data(): %s\n", full_data_path);
  }


  //WE'LL WANT TO DO SOMETHING LIKE--IS THIS NODE A VALUE NODE, THEN PROCESS.

  //now check for value at this node and copy
  char *cp = NULL;
  //data_path needs to be of type vtw_path!!
  vtw_path vpath;
  init_path(&vpath, full_data_path);
  //lstat for value file BEFORE retrieving
  if (value_exists(full_data_path) && get_value(&cp, &vpath) == 0) {
    //terminating value need to create new terminating node here!
    struct VyattaNode *vn = calloc(1,sizeof(struct VyattaNode));
    GNode *new_node = g_node_new(vn);
    new_node = insert_sibling_in_order(node,new_node);
    //    new_node = g_node_insert(node, -1, new_node);
    vn->_data._name = cp;
    vn->_data._value = FALSE;//TRUE; //data value
    vn->_data._operation = op;
    vn->_priority = LOWEST_PRIORITY;
    vn->_data._path = malloc(MAX_LENGTH_DIR_PATH*sizeof(char));
    sprintf(vn->_data._path,"%s",rel_data_path);
    final_node = TRUE;
  }
  /*
    NOTE: will need to implement ptr copy over for the config data that 
    traverses up multi-nodes. Currently this will just read the data from
    the parser AGAIN, but in the name of memory and performance efficiency
    this should be a copy of the already processed data.
   */

  //Now dig up the configuration data 
  char *config_path = get_config_path(node);

  if (config_path != NULL) {
    char *conf_base = (char*)get_tdirp();
    char buf[MAX_LENGTH_HELP_STR];
    sprintf(buf,"%s/%snode.def",conf_base,config_path);
    struct stat s;
    if (g_debug) {
      printf("unionfs::retrieve_data(): config path: %s\n",buf);
    }

    struct VyattaNode* vn = (struct VyattaNode*)node->data;
    vtw_def def;
    memset(&def, 0, sizeof(def));
    if ((lstat(buf,&s) == 0) && S_ISREG(s.st_mode)) {
      if (parse_def(&def, buf, FALSE) == 0) {
	if (g_debug) {
	  printf("[FOUND node.def]");
	}
	//either multi or tag--shouldn't have made a difference, but arkady was confused.
	vn->_config._multi = (def.tag | def.multi); 
      }
    }

    vn->_config._def = def;
    vn->_config._path = config_path;
    char *tmp = malloc(sizeof(char)*MAX_LENGTH_DIR_PATH);
    strcpy(tmp,rel_data_path);
    strcat(tmp,"/");
    vn->_data._path = tmp;

    //will stamp an embedded node as a value node
    if (G_NODE_IS_ROOT(node) == FALSE) {
      struct VyattaNode* vn_parent = (struct VyattaNode*)node->parent->data;
      if (vn_parent->_config._multi == TRUE) {
	((struct VyattaNode*)node->data)->_data._value = TRUE;

	//now let's patch up the def multi-nodes
	//move the def for the multinode from the parent to the value node
	struct VyattaNode* vn2 = (struct VyattaNode*)node->data;
	if (final_node == FALSE) { //non-term multi
	  if (g_node_n_children(node->parent) == 1) {
	    vn2->_config._def = ((struct VyattaNode*)node->parent->data)->_config._def;
	    memset(&((struct VyattaNode*)node->parent->data)->_config._def, 0, sizeof(vtw_def));
	  }
	  else { //find node other than myself to copy defs across
	    GNode *first_child = g_node_first_child(node->parent);
	    if (first_child == node) {
	      first_child = g_node_next_sibling(first_child);
	    }	    
	    vn2->_config._def = ((struct VyattaNode*)first_child->data)->_config._def;
	  }
	}
      }
    }
    
    if (g_debug) {
      printf("\n");
    }
  }

  if (final_node == TRUE) {
    //move defs to child...
    get_term_data_values(node);

    //fix operation on parent because this is a final node
    char buf[MAX_LENGTH_HELP_STR];
    sprintf(buf,"%s/%s",get_adirp(),rel_data_path);
    struct stat s;
    if ((lstat(buf,&s) != 0) && S_ISREG(s.st_mode)) {
      struct VyattaNode* vn = (struct VyattaNode*)node->data;
      vn->_data._operation = K_CREATE_OP;
    }
    return;
  }
  
  //iterate over directory here
  DIR *dp;
  if ((dp = opendir(full_data_path)) == NULL){
    if (g_debug) {
      //could also be a terminating value now
      printf("unionfs::retrieve_data(), failed to open directory: %s\n", full_data_path);
    }
    return;
  }
  //finally iterate over valid child directory entries

  boolean processed = FALSE;
  struct dirent *dirp = NULL;
  while ((dirp = readdir(dp)) != NULL) {
    if (strcmp(dirp->d_name, ".") != 0 && 
	strcmp(dirp->d_name, "..") != 0 &&
	strcmp(dirp->d_name, MODIFIED_FILE) != 0 &&
	strcmp(dirp->d_name, DEF_FILE) != 0 &&
	strcmp(dirp->d_name, WHITEOUT_FILE) != 0 &&
	strcmp(dirp->d_name, VALUE_FILE) != 0) {
      processed = TRUE;
      char *data_buf = malloc(MAX_LENGTH_DIR_PATH*sizeof(char));
      if (strncmp(dirp->d_name,DELETED_NODE,4) == 0) { 
	strcpy(data_buf,dirp->d_name+4); //SKIP THE .WH.
	
	//create new node and insert...
	struct VyattaNode *vn = calloc(1,sizeof(struct VyattaNode));
	vn->_data._name = data_buf;
	vn->_data._value = FALSE;
	vn->_data._operation = K_DEL_OP;
	vn->_priority = LOWEST_PRIORITY;
	
	char new_data_path[MAX_LENGTH_DIR_PATH];
	sprintf(new_data_path,"%s/%s",rel_data_path,data_buf);
	
	GNode *new_node = g_node_new(vn);
	//	new_node = g_node_insert(node, -1, new_node);
	new_node = insert_sibling_in_order(node,new_node);

	//will need to enter a special recursion against the active configuration to mark nested delete nodes
	retrieve_data(new_data_path,new_node,get_adirp(),K_DEL_OP);
      }
      else {
	strcpy(data_buf,dirp->d_name);
	//create new node and insert...
	struct VyattaNode *vn = calloc(1,sizeof(struct VyattaNode));
	vn->_data._name = data_buf;
	vn->_data._value = FALSE;
	vn->_priority = LOWEST_PRIORITY;

	char new_data_path[MAX_LENGTH_DIR_PATH];
	sprintf(new_data_path,"%s/%s",rel_data_path,data_buf);

	char active_data_path[MAX_LENGTH_DIR_PATH];
	sprintf(active_data_path,"%s%s",get_adirp(),rel_data_path);
	struct stat s;

	if (lstat(active_data_path,&s) == 0) {
	  vn->_data._operation = K_NO_OP;
	}
	else {
	  vn->_data._operation = K_CREATE_OP;
	  ((struct VyattaNode*)node->data)->_data._operation = K_CREATE_OP;
	}
	//set recursed entry op to del
	if (op == K_DEL_OP) {
	  vn->_data._operation = K_DEL_OP;
	}
	GNode *new_node = g_node_new(vn);
	//	new_node = g_node_insert(node, -1, new_node);
	new_node = insert_sibling_in_order(node,new_node);
	retrieve_data(new_data_path,new_node,root,vn->_data._operation);
      }
    }
  }
  //catch hanging case where embedded multinode is new with no children
  if (processed == FALSE) {
    char active_data_path[MAX_LENGTH_DIR_PATH];
    sprintf(active_data_path,"%s/%s",get_adirp(),rel_data_path);
    struct stat s;
    if ((lstat(active_data_path,&s) != 0)) {
      ((struct VyattaNode*)node->data)->_data._operation = K_CREATE_OP;
    }
  }

  closedir(dp);
  return;
}


/**
 *
 **/
GNode*
common_get_local_session_data()
{
  //get root directory
  char *data_path = malloc(sizeof(char)*MAX_LENGTH_DIR_PATH);
  data_path[0] = '\0';

  struct VyattaNode *vn = calloc(1,sizeof(struct VyattaNode));
  vn->_data._name = NULL; //root node has null
  vn->_data._operation = K_NO_OP;
  vn->_priority = LOWEST_PRIORITY;

  //create first node
  GNode *root_node = g_node_new(vn);

  //iterate through recursive calls to parse_new() calls (see original commit())
  retrieve_data(data_path,root_node,get_cdirp(),K_SET_OP);

  apply_priority(root_node);

  return root_node;
}


/**
 *
 **/
boolean
value_exists(char *path)
{
  char buf[MAX_LENGTH_DIR_PATH];
  sprintf(buf, "%s/%s",path,VALUE_FILE);
  struct stat stat_buf;
  return !stat(buf,&stat_buf);
}

/**
 * need to compute parent as it might not be in the node structure
 *
 **/
void
common_set_parent_context(char *cpath, char *dpath)
{
  if (g_debug) {
    printf("common_set_parent_context(incoming): %s, %s\n",cpath,dpath);
  }
  //strip off last path and set
  int index = strlen(cpath)-1;
  if (cpath[index] == '/') {
    while (TRUE) {
      if (cpath[--index] != '/') {
	cpath[index] = '\0';
	break;
      }
    }
  }
  char *ptr = rindex(cpath,'/');
  if (ptr != NULL) {
    *ptr = '\0';
  }
  set_path(cpath,TRUE);

  index = strlen(dpath)-1;
  if (dpath[index] == '/') {
    while (TRUE) {
      if (dpath[--index] != '/') {
	dpath[index] = '\0';
	break;
      }
    }
  }
  ptr = rindex(dpath,'/');
  if (ptr != NULL) {
    *ptr = '\0';
  }
  set_path(dpath,FALSE);
  if (g_debug) {
    printf("common_set_parent_context: %s, %s\n",cpath,dpath);
  }
}

/**
 *
 **/
void
common_set_context(char *cpath, char *dpath)
{
  if (g_debug) {
    printf("common_set_context: %s, %s\n",cpath,dpath);
  }
  set_path(cpath,TRUE);
  set_path(dpath,FALSE);
}

/**
 *
 **/
void
set_path(char *path, boolean config)
{
  //set t_path, m_path
  //tokenize path and iterate
  if (config == FALSE) {
    init_path(&m_path, get_mdirp());
  }
  else {
    init_path(&t_path, get_tdirp());
  }

  char* start_ptr = NULL;
  char* end_ptr = NULL;
  
  if (path == NULL) {
    if (g_debug) {
      printf("unionfs::set_path() null value on entry\n");
    }
    return;
  }

  start_ptr = path;
  while((end_ptr = index(start_ptr+1,'/')) != NULL) {
    char tmp[1024];
    
    if (*start_ptr == '/') {
      ++start_ptr;
    }

    int size = end_ptr-start_ptr;
    if (size < 1 || size > 1024) {
      /*
      if (g_debug) {
	if (config == FALSE) {
	  printf("unionfs::set_path(): %s, %s\n", path,m_path.path);
	}
	else {
	  printf("unionfs::set_path(): %s, %s\n", path,t_path.path);
	}
      }
      */
      return;
    }

    memcpy(tmp, start_ptr, size);
    tmp[size] = '\0';

    if (config == FALSE) {
      push_path_no_escape(&m_path, tmp); //data
    }
    else {
      push_path_no_escape(&t_path, tmp); //config
    }
    start_ptr = end_ptr;
  }
  /*
  if (g_debug) {
    if (config == FALSE) {
      printf("unionfs::set_path(): %s, %s\n", path,m_path.path);
    }
    else {
      printf("unionfs::set_path(): %s, %s\n", path,t_path.path);
    }
  }
  */
}

/**
 * NEED TO PROTECT AGAINST NESTED COMMIT NODES. CANNOT BE SUPPORTED
 * IN CURRENT HIERARCHICAL STRUCTURE WITHOUT CHANGING HOW UNDERLYING
 * SYSTEM MAINTAINS DATA.
 *
 **/
void
common_commit_copy_to_live_config(GNode *node, boolean test_mode)
{
  //first check for existence of path before committing
  char *path = ((struct VyattaNode*)(node->data))->_data._path;

  if (g_debug) {
    printf("common_commit_copy_to_live_config(): %s\n",path);
  }
  char *command = malloc(MAX_LENGTH_DIR_PATH);
  static const char format0[]="mkdir -p %s ; /bin/true";
  static const char format1[]="cp -r -f %s/* %s"; /*mdirp, tmpp*/

  static const char format2[]="sudo umount %s"; //mdirp
  
  static const char format4[]="rm -rf %s/{.*,*} >&/dev/null ; /bin/true"; /*cdirp*/

  //walk up tree until diverge or skip
  static const char format6[]="cp -rf %s/* -t %s";/*tmpp, adirp*/ 

  static const char format7[]="rm -fr %s >&/dev/null ; /bin/true"; /*tmpp*/
  
  static const char format8[]="sudo mount -t unionfs -o dirs=%s=rw:%s=ro unionfs %s"; //cdirp, adirp, mdirp

  set_echo(TRUE);

  char mbuf[MAX_LENGTH_DIR_PATH];
  sprintf(mbuf,"%s%s",get_mdirp(),path);
  char cbuf[MAX_LENGTH_DIR_PATH];
  sprintf(cbuf,"%s%s",get_cdirp(),path);
  char tbuf[MAX_LENGTH_DIR_PATH];
  sprintf(tbuf,"%s%s",get_tmpp(),path);
  char abuf[MAX_LENGTH_DIR_PATH];
  sprintf(abuf,"%s%s",get_adirp(),path);

  char mbuf_root[MAX_LENGTH_DIR_PATH];
  sprintf(mbuf_root,"%s",get_mdirp());
  char cbuf_root[MAX_LENGTH_DIR_PATH];
  sprintf(cbuf_root,"%s",get_cdirp());
  char tbuf_root[MAX_LENGTH_DIR_PATH];
  sprintf(tbuf_root,"%s",get_tmpp());
  char abuf_root[MAX_LENGTH_DIR_PATH];
  sprintf(abuf_root,"%s",get_adirp());

  //only operate on path if it exists
  struct stat s;
  if ((lstat(mbuf,&s) != 0) && S_ISREG(s.st_mode)) {
    printf("common_commit_copy_to_live_config(): failed to find: %s, aborting copy\n",mbuf);
    return;
  }

  //mkdir temp merge
  sprintf(command,format0,tbuf);
  if (g_debug) {
    printf("%s\n",command);
    fflush(NULL);
  }
  if (test_mode == FALSE) {
    system(command);
  }

  //cp merge to temp merge
  sprintf(command, format1, mbuf, tbuf);
  if (g_debug) {
    printf("%s\n",command);
    fflush(NULL);
  }
  if (test_mode == FALSE) {
    system(command);
  }

  //unmount temp (i.e. rm merge)
  sprintf(command, format2, mbuf_root);
  if (g_debug) {
    printf("%s\n",command);
    fflush(NULL);
  }
  if (test_mode == FALSE) {
    system(command);
  }

  piecewise_copy(node, test_mode);

  sprintf(command, format8, cbuf_root,abuf_root,mbuf_root);
  if (g_debug) {
    printf("%s\n",command);
    fflush(NULL);
  }
  if (test_mode == FALSE) {
    system(command);
  }

  fflush(NULL);

  free(command);
  return;
}  

/**
 *
 **/
void
common_commit_clean_temp_config(boolean test_mode)
{
  if (g_debug) {
    printf("common_commit_clean_temp_config()\n");
  }
  //first clean up the root
  //  common_commit_copy_to_live_config("/");

  char *command;
  command = malloc(MAX_LENGTH_DIR_PATH);
  static const char format2[]="sudo umount %s"; //mdirp
  static const char format3[]="rm -f %s/" MOD_NAME " >&/dev/null ; /bin/true"; /*tmpp*/
  static const char format5[]="rm -fr %s/{.*,*} >&/dev/null ; /bin/true"; /*cdirp*/
  static const char format7[]="sudo mount -t unionfs -o dirs=%s=rw:%s=ro unionfs %s"; //cdirp, adirp, mdirp


  char tbuf[MAX_LENGTH_DIR_PATH];
  sprintf(tbuf,"%s",get_tmpp());
  char cbuf[MAX_LENGTH_DIR_PATH];
  sprintf(cbuf,"%s",get_cdirp());
  char mbuf[MAX_LENGTH_DIR_PATH];
  sprintf(mbuf,"%s",get_mdirp());
  char abuf[MAX_LENGTH_DIR_PATH];
  sprintf(abuf,"%s",get_adirp());

  set_echo(TRUE);

  sprintf(command, format2, mbuf);
  if (g_debug) {
    printf("%s\n",command);
    fflush(NULL);
  }

  if (test_mode == FALSE) {
    system(command);
  }

  sprintf(command, format3, tbuf);
  if (g_debug) {
    printf("%s\n",command);
    fflush(NULL);
  }
  if (test_mode == FALSE) {
    system(command);
  }

  sprintf(command, format3, cbuf);
  if (g_debug) {
    printf("%s\n",command);
    fflush(NULL);
  }
  if (test_mode == FALSE) {
    system(command);
  }

  sprintf(command, format5, cbuf);
  if (g_debug) {
    printf("%s\n",command);
    fflush(NULL);
  }
  if (test_mode == FALSE) {
    system(command);
  }

  sprintf(command, format7, cbuf,abuf,mbuf);
  if (g_debug) {
    printf("%s\n",command);
    fflush(NULL);
  }
  if (test_mode == FALSE) {
    system(command);
  }

  /* notify other users in config mode */
  system("/opt/vyatta/sbin/vyatta-cfg-notify");

  free(command);
  return;
}


void
match_priority_node(GNode *node, gchar** tok_str, int pri)
{
  int index = g_node_depth(node)-1;
  if (tok_str[index] == NULL) {
    //MATCHED TO THE END
    ((struct VyattaNode*)node->data)->_priority = pri;
    return;
  }
  //iterate over children for a potential match
  GNode *child = g_node_first_child(node);
  while (child != NULL) {
    char *compval = ((struct VyattaNode*)child->data)->_data._name;
    if (strncmp(compval,tok_str[index],strlen(compval)) == 0) {
      match_priority_node(child,tok_str,pri);
    }
    else if (strncmp(NODE_TAG_FILE,tok_str[index],strlen(NODE_TAG_FILE)) == 0) {
      match_priority_node(child,tok_str,pri);
    }
    child = g_node_next_sibling(child);
  }
  return;
}

/**
 *
 *
 **/
void
set_node_priority(GNode *root_node,char* path,unsigned long pri)
{
  if (root_node == NULL) {
    return;
  }
  gchar** tok_str = g_strsplit(path,"/",MAX_DEPTH);

  struct PriData pri_data;

  pri_data._pri = pri;
  pri_data._tok_str = tok_str;

  match_priority_node(root_node,tok_str,pri);

  g_strfreev(tok_str);
  return;
}


/**
 *
 **/
void
apply_priority(GNode *root_node)
{
  //parse file and find node and set value
  FILE *fp = fopen(NODE_PRIORITY_FILE, "r");
  if (fp != NULL) {
    if (g_debug) {
      printf("unionfs::apply_priority(), found priority file\n");
    }

    char str[1025];
    while (fgets(str, 1024, fp) != 0) {
      gchar** tok_str = g_strsplit(str," ",3);
      if (tok_str[0] == NULL || tok_str[1] == NULL) {
	continue;
      }
      char *path = tok_str[1];
      if (g_debug) {
	printf("unionfs::apply_priority(), working on this %s\n",path);
      }

      //now apply to node
      set_node_priority(root_node,path,strtoul(tok_str[0],NULL,10));
      g_strfreev(tok_str);
    }
    fclose(fp);
  }
}

/**
 *
 **/
struct VyattaNode*
copy_vyatta_node(struct VyattaNode* vn)
{
  struct VyattaNode *new_vn = calloc(1,sizeof(struct VyattaNode));

  if (vn->_data._name != NULL) {
    new_vn->_data._name = malloc(MAX_LENGTH_DIR_PATH*sizeof(char));
    strcpy(new_vn->_data._name,vn->_data._name);
  }
  new_vn->_data._value = vn->_data._value;
  if (vn->_data._path != NULL) {
    new_vn->_data._path = malloc(MAX_LENGTH_DIR_PATH*sizeof(char));
    strcpy(new_vn->_data._path,vn->_data._path);
  }
  new_vn->_data._operation = vn->_data._operation;
  new_vn->_priority = vn->_priority;

  new_vn->_config._multi = new_vn->_config._multi;
  //  new_vn->_config._def = new_vn->_config._def; //cpy this?
  if (vn->_config._default != NULL) {
    new_vn->_config._default = malloc(MAX_LENGTH_DIR_PATH*sizeof(char));
    strcpy(new_vn->_config._default,vn->_config._default);
  }
  if (vn->_config._path != NULL) {
    new_vn->_config._path = malloc(MAX_LENGTH_DIR_PATH*sizeof(char));
    strcpy(new_vn->_config._path,vn->_config._path);
  }
  return new_vn;
}

/**
 *
 **/
void
get_term_data_values(GNode *node)
{
  struct VyattaNode* vn = (struct VyattaNode*)node->data;
  char full_new_data_path[MAX_LENGTH_DIR_PATH];
  char full_active_data_path[MAX_LENGTH_DIR_PATH];
  sprintf(full_active_data_path,"%s/%s",get_adirp(),vn->_data._path);
  sprintf(full_new_data_path,"%s/%s",get_mdirp(),vn->_data._path);

  GData *datalist;
  g_datalist_init(&datalist);

  //now check for value at this node and copy
  char *cp = NULL;
  //data_path needs to be of type vtw_path!!
  vtw_path vpath;
  //lstat for value file BEFORE retrievin
  gchar **tok_str_new = NULL;
  gchar **tok_str_active = NULL;

  //create full_data_path here
  
  init_path(&vpath, full_active_data_path);
  if (value_exists(full_active_data_path) && get_value(&cp, &vpath) == 0) {
    tok_str_active = g_strsplit(cp,"\n",0);
  }


  init_path(&vpath, full_new_data_path);
  if (value_exists(full_new_data_path) && get_value(&cp, &vpath) == 0) {
    tok_str_new = g_strsplit(cp,"\n",0);
  }

  if (vn->_config._multi == TRUE) {
    //add active elements
    int i;
    for (i = 0; tok_str_active !=  NULL && tok_str_active[i] != NULL; ++i) {
      struct ValueData *data;
      data = (struct ValueData*)calloc(1, sizeof(struct ValueData));
      //HANDLE EMPTY NEW CONFIG
      data->_state = K_DEL_OP;
      g_datalist_set_data(&datalist, tok_str_active[i], data);
    }
    
    //add value elements not found in set yet
    for (i = 0; tok_str_new !=  NULL && tok_str_new[i] != NULL; ++i) {
      gpointer g;
      if ((g = g_datalist_get_data(&datalist,tok_str_new[i])) == NULL) {
	struct ValueData *data;
	data = (struct ValueData*)calloc(1, sizeof(struct ValueData));
	data->_state = K_CREATE_OP;
	g_datalist_set_data(&datalist, tok_str_new[i], data);
      }
      else {
	((struct ValueData*)g)->_state = K_NO_OP;
      }
    }
  }
  else { //leaf
    struct ValueData *data;
    data = (struct ValueData*)calloc(1, sizeof(struct ValueData));
    if ((tok_str_active == NULL || tok_str_active[0] == NULL) &&
	(tok_str_new == NULL || tok_str_new[0] == NULL)) {
  //      data->_state = K_NO_OP;
  //      g_datalist_set_data(&datalist, tok_str_active[0], data);
    }
    else if (tok_str_active == NULL || tok_str_active[0] == NULL) {
      data->_state = K_CREATE_OP;
      g_datalist_set_data(&datalist, tok_str_new[0], data);
    }
    else if (tok_str_new == NULL || tok_str_new[0] == NULL) {
      data->_state = K_DEL_OP;
      g_datalist_set_data(&datalist, tok_str_active[0], data);
    }
    else {
      if (strcmp(tok_str_active[0],tok_str_new[0]) != 0) {
	data->_state = K_SET_OP;
	g_datalist_set_data(&datalist, tok_str_new[0], data);
      }
      else {
	data->_state = K_NO_OP;
	g_datalist_set_data(&datalist, tok_str_new[0], data);
      }
    }
  }

  //now let's process the node's values....

  g_datalist_foreach(&datalist, dlist_test_func, node);
  struct VyattaNode *vn_parent = (struct VyattaNode*)node->data;
  memset(&vn_parent->_config._def, 0, sizeof(vtw_def));

  g_strfreev(tok_str_new);
  g_strfreev(tok_str_active);

  //  g_dataset_destroy(&datalist);

  return;
}

/**
 *
 **/
void
dlist_test_func(GQuark key_id,gpointer data,gpointer user_data)
{
  if (key_id == 0) {
    return;
  }
  GNode *node = (GNode*)user_data;
  struct VyattaNode *vn = (struct VyattaNode*)node->children->data;
  struct VyattaNode *vn_parent = (struct VyattaNode*)node->data;
  struct VyattaNode *new_vn = NULL;
  //single entry has alread been created.


  if (vn->_data._value == TRUE) {
    new_vn = copy_vyatta_node(vn);
    GNode *new_node = g_node_new(new_vn);
    //g_node_insert(node, -1, new_node);
    insert_sibling_in_order(node,new_node);
    new_vn->_config._def = vn->_config._def;
    //    strcat(new_vn->_data._path,"/value");
  }
  else {
    new_vn = vn;
    strcat(new_vn->_data._path,"/value");
  }
  new_vn->_data._value = TRUE;
  strcpy(new_vn->_data._name,(char*)g_quark_to_string(key_id));
  new_vn->_config._path = malloc(MAX_LENGTH_DIR_PATH*sizeof(char));
  sprintf(new_vn->_config._path,"%s/node.tag",vn_parent->_config._path);
  new_vn->_data._operation = ((struct ValueData*)data)->_state;
  new_vn->_config._def = vn_parent->_config._def;
}


/**
 *
 **/
GNode*
insert_sibling_in_order(GNode *parent, GNode *child)
{
  //find alphabetical order to insert child into sibling
  GNode *sibling = parent->children;
  while (sibling != NULL) {
    if (strcmp((((struct VyattaNode*)(child->data))->_data._name),((struct VyattaNode*)(sibling->data))->_data._name) > 0) { 
      break;
    }
    sibling = sibling->next;
  }
  GNode *new_node = g_node_insert_after(parent, sibling, child);
  return new_node;
}

//needed for iteration below
struct SrcDst {
  char *_src;
  char *_dst;
  boolean _test_mode;
};

/**
 *
 **/
void
piecewise_copy(GNode *root_node, boolean test_mode)
{
  struct SrcDst sd;
  sd._src = get_tmpp(); //copy of merged config
  sd._dst = get_adirp(); //active config
  sd._test_mode = test_mode;
  
  //COPY FROM TOP DOWN
  g_node_traverse(root_node,
		  G_PRE_ORDER,
		  G_TRAVERSE_ALL,
		  -1,
		  (GNodeTraverseFunc)copy_func,
		  (gpointer)&sd);
  
  //delete needs to apply to changes only as src
  sd._src = get_cdirp(); //changes only config
  //DELETE FROM BOTTOM UP, stop on finding children
  g_node_traverse(root_node,
		  G_POST_ORDER,
		  G_TRAVERSE_ALL,
		  -1,
		  (GNodeTraverseFunc)delete_func,
		  (gpointer)&sd);
}

/**
 *
 *
 **/
static gboolean
copy_func(GNode *node, gpointer data)
{
  if (node == NULL) {
    return FALSE;
  }

  char *command = malloc(MAX_LENGTH_DIR_PATH);

  struct SrcDst *sd = (struct SrcDst*)data;
  static const char format[]="mkdir -p %s%s";/*tmpp, adirp*/ 
  static const char format_value[]="cp %s%s{node.val,def} %s%s. 2>/dev/null";/*tmpp, adirp*/ 
  char *path = ((struct VyattaNode*)(node->data))->_data._path;

  //might not work for terminating multinodes as the node.val won't be copied
  if (((struct VyattaNode*)(node->data))->_data._value == TRUE &&
      ((struct VyattaNode*)(node->data))->_config._def.tag == FALSE) {
    //THIS IS ONLY FOR NODE.VAL (or leafs, term multis)
    char *parent_path = ((struct VyattaNode*)(node->parent->data))->_data._path;
    sprintf(command,format_value,sd->_src,parent_path,sd->_dst,parent_path);
    if (g_debug) {
      printf("%s\n",command);
      fflush(NULL);
    }
    if (sd->_test_mode == FALSE) {
      system(command);
    }
  }
  else {
    if (!IS_DELETE(((struct VyattaNode*)(node->data))->_data._operation)) {
      sprintf(command,format,sd->_dst,path);
      if (g_debug) {
	printf("%s\n",command);
	fflush(NULL);
      }
      if (sd->_test_mode == FALSE) {
	system(command);
      }
    }
  }
  free(command);
  return FALSE;
}

/**
 *
 *
 **/
static gboolean
delete_func(GNode *node, gpointer data)
{
  if (node == NULL) {
    return FALSE;
  }

  char *command = malloc(MAX_LENGTH_DIR_PATH);

  struct SrcDst *sd = (struct SrcDst*)data;
  static const char format[]="rm -f %s%s{*,.*} >&/dev/null;rmdir %s%s >&/dev/null ; /bin/true";  //need to remove opaque file.
  static const char format_force_delete[]="rm -f %s%s{*,.*} >&/dev/null;rm -fr %s%s >&/dev/null ; /bin/true";  //force delete as this is a delete operation with dependency 
  static const char delete_format[]="rm %s%s../.wh.%s >&/dev/null"; 
  
  char *path = ((struct VyattaNode*)(node->data))->_data._path;

  //does this node have any children that have not been copied????

  //NEED RM -FV on changes only directory!!!! for normal removal!!!


  //WILL ONLY REMOVE DIRS WITHOUT CHILD DIRS--just what we want..
  sprintf(command,format,sd->_src,path,sd->_src,path);
  if (g_debug) {
    printf("%s\n",command);
    fflush(NULL);
  }
  if (sd->_test_mode == FALSE) {
    system(command);
  }

  //if this is a deletion operation, need to remove
  if (IS_DELETE(((struct VyattaNode*)(node->data))->_data._operation) && 
      !IS_ACTIVE(((struct VyattaNode*)(node->data))->_data._operation)) {

    //DO NOT PERFORM THIS STEP IF THERE ARE SUBDIRECTORIES (only the whiteout file)

    //remove .whiteout file in c directory if encountered in walk.
    sprintf(command,delete_format,sd->_src,path,((struct VyattaNode*)(node->data))->_data._name);
    if (g_debug) {
      printf("%s\n",command);
      fflush(NULL);
    }
    if (sd->_test_mode == FALSE) {
      system(command);
    }
    //if delete then remove entry in active configuration!
    sprintf(command,format_force_delete,sd->_dst,path,sd->_dst,path);
    if (g_debug) {
      printf("%s\n",command);
      fflush(NULL);
    }
    if (sd->_test_mode == FALSE) {
      system(command);
    }
  }
  free(command);

  return FALSE;
}