mi_datagram_parser.c

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/*
 * $Id: mi_datagram.h 1133 2007-04-02 17:31:13Z ancuta_onofrei $
 *
 * Copyright (C) 2007 Voice Sistem SRL
 *
 * This file is part of Kamailio, a free SIP server.
 *
 * Kamailio is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Kamailio is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 *
 * History:
 * ---------
 *  2007-06-25  first version (ancuta)
 */

/*!
 * \file
 * \brief MI_DATAGRAM :: Command parser
 * \ingroup mi
 */


#include <stdio.h>
#include <string.h>
#include <ctype.h>

#include "../../str.h"
#include "../../dprint.h"
#include "../../mi/mi.h"
#include "../../mem/mem.h"
#include "../../mem/shm_mem.h"
#include "datagram_fnc.h"
#include "mi_datagram.h"
#include "mi_datagram_parser.h"

/*static unsigned int mi_parse_buffer_len = 0;

int mi_datagram_parser_init( unsigned int size )
{
   mi_parse_buffer_len = size;

   return 0;
}*/



/*! \brief Parse MI command
      example: mi_parse_node(datagram, &buf, &name, &value)
 * returns -1 = error
 *          0 = ok
 *          1 = end of input
 */
static inline int mi_datagram_parse_node(datagram_stream * data, str *name, str *value)
{
   char *p, *pmax;
   char *start, *start1;
   char *mark_nsp;
   int newline_found = 0;

   LM_DBG("the remaining datagram to be parsed is %s and %i in length \n",
         data->current,data->len);

   p =data->current;
   start1 = start = p;
   if(data->len > DATAGRAM_SOCK_BUF_SIZE) {
      LM_ERR("overflow while parsing the received datagram\n");
      goto parse_err;
   }
   pmax  = start + data->len ;

   /* remove leading spaces */
   for( ; start<pmax && isspace((int)*start) ; start++ );
   /*no valuable data---end of input*/
   if(start == pmax)
      return 1;

   /* init */
   name->s = value->s = 0;
   name->len = value->len = 0;

   mark_nsp = 0;

   /* start parsing */
   if (*start!='"') {
      LM_DBG("the string is not just a quoted string\n");
      /* look for the atribute name */

      p = mark_nsp = start;
      while ( p!=pmax && (( *p!=MI_ATTR_VAL_SEP1) || p+1==pmax ||*(p+1)!=MI_ATTR_VAL_SEP2) ) {
         if (!isspace((int)*p)) {
            if (*p=='"') {
               LM_DBG("found \" before attr_separator\n");
               goto parse_err;
            }
            mark_nsp = p;
         }
         if(*p=='\n' && p!=(pmax -1)) {
            LM_DBG("found newline before attr_separator--we have just the "
               "attribute's value\n");
            mark_nsp++;
            pmax = ++p;
            break;
         }else if (p == (pmax-1)){
            mark_nsp++;
            pmax = ++p;
            LM_DBG("just a value, no new line");
            break;
         }
         p++;
      }

      if (p!=pmax) {
         /* we have found the separator */
         LM_DBG("we've found the attr_separator\n");
         if (p==start) {
            /* empty attr name */
            LM_DBG("empty attr_name\n");
         } else {
            name->s = start;
            name->len = mark_nsp - start+1;
            LM_DBG("attr name <%.*s> found\n",name->len, name->s);
         }

         p += 2; /* for separator */
            
         /* consume the trailing spaces */
         for( ; p!=pmax && isspace((int)*p) ; p++) {
            if(*p=='\n') {
               LM_DBG("empty value\n");
               /* empty value.....we are done */
               goto done;
            }
         }
         /*LM_DBG("p is %s case2\n",p);*/

         if(p==pmax && *p=='\n') {
            LM_DBG("empty value\n");
               /* empty value.....we are done */
            goto done;
         }
         /*LM_DBG("p is %s case1\n",p);*/
         /* value (only if not quoted ) */
         if (*p!='"') {
            LM_DBG("not quoted value, p is %c \n", *p);
            for( start=p ; p!=pmax ; p++ ) {
               if (!isspace((int)*p)) {
                  if (*p=='"') {
                     goto parse_err;
                  }
                  mark_nsp = p;
                  LM_DBG("nsp is %p ,p is %p, pmax is %p and *p is %c\n",
                     mark_nsp, p, pmax,*p);
               }
               if(*p=='\n') { /*end of the node*/
                  pmax = p;
                  break;
               }
            }
         
            value->s = start;
            value->len = mark_nsp - start+1;
            LM_DBG("*start is %c and start is %p\n",*start, start);
            LM_DBG("attr value <%s> found\n"/*,value->len*/, value->s);
            goto done;
         }
         /* quoted value....continue */
      } else {
         /* we have an empty name ... and we read a non-quoted value */
         value->s = start;
         value->len = mark_nsp  - start;
         LM_DBG("empty name, attr not quoted value <%.*s> found\n",
               value->len, value->s);
         goto done;
      }
   } else {
      p = start; /*send the value only: as a quoted string*/
   }
   /*we have a quoted value*/
   LM_DBG("we have a  quoted value, %s\n", p);
   start = p+1; /*skip the first "*/
   value->s = start;

   p = start;
   /* parse the buffer and look for " */
   while (p<pmax) {
      if (*p=='"' && start!=p) { /*search the closing "*/

         LM_DBG("\" found p is %s\n",p);

         if (start+1!=p && *(p-1)=='\\') {
            LM_DBG("skipping %c",*p);
            /* skip current char */
            memmove( p-1, p, pmax-p);
            pmax--; 
         } else {
            LM_DBG("we have reached the end of attr value, p is %s\n", p);
            /* end of value */
            value->len = p - value->s;
            LM_DBG("attr value <%.*s> found\n",value->len, value->s);
            
            /* is the line ending propely (only spaces) ? */
            p++;
            for(; p!=pmax && isspace((int)*p) ; p++)
            {
               if(*p=='\n') {
                  /*case : ""quoted string"  \n on a line */
                  LM_DBG("line ended properly case1\n");
                  pmax = p;
                  break;
               }
            }
            if (p!=pmax )/*didn't find the second " on the current line*/
            {
               LM_ERR("didn't find newline case1 \n");
               goto parse_err;
            }
            newline_found = 1;
            /* found! */
            goto done;
         }
      } else {
         p++;
      }
   }

   if(p== pmax && !newline_found) {
      LM_ERR("didn't find newline case2\n");
      goto parse_err;
   }

done:
   /*set the current datagram's offset */
   LM_DBG("1 data->len is %i\n",data->len);
   data->len -= p-start1;
   LM_DBG("2 data->len is %i\n",data->len);
   data->current = p;
   return 0;
parse_err:
   LM_ERR("parse error around %c\n",*p);
   return -1;
}



/*! \brief parsing the datagram buffer*/
struct mi_root * mi_datagram_parse_tree(datagram_stream * datagram) {
   struct mi_root *root;
   struct mi_node *node;
   str name;
   str value;
   int ret;

   root = init_mi_tree(0,0,0);
   if (!root) {
      LM_ERR("the MI tree cannot be initialized!\n");
      goto error;
   }
   if(!datagram || datagram->current[0] == '\0')
   {
      LM_DBG("no data in the datagram\n");
      return root;
   }

   node = &root->node;

   name.s = value.s = 0;
   name.len = value.len = 0;

   /* every tree for a command ends with a \n that is alone on its line */
   while ((ret=mi_datagram_parse_node(datagram, &name, &value))>=0 ) {
      
      if(ret == 1)
         return root;
      LM_DBG("adding node <%.*s> ; val <%.*s>\n",
            name.len,name.s, value.len,value.s);

      if(!add_mi_node_child(node,0,name.s,name.len,value.s,value.len)){
         LM_ERR("cannot add the child node to the tree\n");
         goto error;
      }
      LM_DBG("the remaining datagram has %i bytes\n",datagram->len);
      /*end condition*/
      if(datagram->len == 0) {
         LM_DBG("found end of input\n");
         return root;
      }
   }

   LM_ERR("parse error!\n");
error:
   if (root)
      free_mi_tree(root);
   return 0;
}