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lcas_db_read.c

Go to the documentation of this file.

/*                                                                                                            
 * Copyright (c) 2001 EU DataGrid.                                                                             
 * For license conditions see http://www.eu-datagrid.org/license.html                                          
 *
 * Copyright (c) 2001, 2002 by 
 *     Martijn Steenbakkers <martijn@nikhef.nl>,
 *     David Groep <davidg@nikhef.nl>,
 *     NIKHEF Amsterdam, the Netherlands
 */

/*****************************************************************************
                            Include header files
******************************************************************************/
#include <stdlib.h>
#include <malloc.h>
#include <stdio.h>
#include <string.h>
#include "lcas_log.h"
#include "_lcas_db_read.h"

/******************************************************************************
                                Definitions
******************************************************************************/
#define MAXDBENTRIES 250 
#define MAXPAIRS     2   
#define WHITESPACE_CHARS " \t\n" 
#define QUOTING_CHARS    "\"" 
#define ESCAPING_CHARS   "\\" 
#define COMMENT_CHARS    "#" 
#define PAIR_SEP_CHARS ","

#define VARVAL_SEP_CHARS "="

/*
 * Characters that terminate pairs, values and variables in the lcas database file. This
 * is a combination of whitespace and separators.
 */
#define PAIR_TERMINATOR_CHARS PAIR_SEP_CHARS WHITESPACE_CHARS

#define VARVAL_TERMINATOR_CHARS VARVAL_SEP_CHARS WHITESPACE_CHARS

#ifndef NUL
#define NUL '\0' 
#endif

/******************************************************************************
                          Module specific prototypes
******************************************************************************/
static int lcas_db_read_entries(FILE *);
static int lcas_db_parse_line(char *, lcas_db_entry_t **);
static int lcas_db_parse_pair(char *, char **, char **);
static int lcas_db_parse_string(char **);

/******************************************************************************
                       Define module specific variables
******************************************************************************/
static lcas_db_entry_t *  lcas_db_list=NULL; 
/******************************************************************************
    Function: lcas_db_read
    documentation in _lcas_db_read.h
******************************************************************************/
lcas_db_entry_t ** lcas_db_read(
        char * lcas_db_fname
)
{
    FILE * lcas_db_fhandle;
    int    no_entries;

    lcas_db_fhandle = fopen(lcas_db_fname, "r");
    if (lcas_db_fhandle == NULL)
    {
        /* Cannot open file */
        return NULL;
    }

    no_entries=lcas_db_read_entries(lcas_db_fhandle);
    if (no_entries < 0)
    {
        lcas_log(0,"lcas.mod-lcas_db_read(): Parse error in line %d of %s\n",
            -(no_entries), lcas_db_fname);
        fclose(lcas_db_fhandle);
        return NULL;
    }
    else if (no_entries > MAXDBENTRIES)
    {
        lcas_log(0,"lcas.mod-lcas_db_read(): Too many entries found in %s\n",
            lcas_db_fname);
        lcas_log(0,"lcas.mod-lcas_db_read(): Only the first %d entries are used\n",
            MAXDBENTRIES);
    }
    fclose(lcas_db_fhandle);

    return &lcas_db_list;
}

static int lcas_db_read_entries(
        FILE * dbstream
)
{
    char               line[1024];
    int                nlines=0;
    int                no_entries=0;
    lcas_db_entry_t *  entry=NULL;

    nlines=0;
    no_entries=0;
/*    lcas_db_fill_entry(no_entries,NULL); */
    while (fgets(line, sizeof(line), dbstream))
    {
        ++nlines;

        if (! lcas_db_parse_line(line, &entry))
        {
            /* parse error, return line number */
            if (entry != NULL) free(entry);
            return -(nlines);
        }
        if (entry != NULL)
        {
            lcas_log_debug(3,"line %d: %s, %s\n",nlines,entry->pluginname,entry->pluginargs);
            /* entry found */
            ++no_entries;
            if (no_entries > MAXDBENTRIES)
            {
                if (entry != NULL) free(entry);
                return no_entries;
            }
            if ( lcas_db_fill_entry(&lcas_db_list, entry)==NULL )
            {
                /* error filling lcas_db */
                if (entry != NULL) free(entry);
                return -(nlines);
            }
            if (entry != NULL) free(entry);
            entry=NULL;
        }
        else
        {
            /* no entry found, but no error */
            continue;
        }
    }
    if (entry != NULL) free(entry);
    return no_entries;
}

/******************************************************************************
    Function: lcas_db_fill_entry
    documentation in _lcas_db_read.h
******************************************************************************/
lcas_db_entry_t * lcas_db_fill_entry(
        lcas_db_entry_t ** list,
        lcas_db_entry_t * entry
)
{
    lcas_db_entry_t * plist;

    if (entry == NULL)
    {
        lcas_log(0,"lcas.mod-lcas_db_fill_entry(): error null entry\n");
        return NULL;
    }

    if (!(*list))
    {
        lcas_log_debug(2,"lcas.mod-lcas_db_fill_entry(): creating first list entry\n");
        *list=plist=(lcas_db_entry_t *)malloc(sizeof(lcas_db_entry_t));
    }
    else
    {
        lcas_log_debug(2,"lcas.mod-lcas_db_fill_entry(): creating new list entry\n");
        plist=*list;
        while (plist->next) plist=plist->next;
        plist=plist->next=(lcas_db_entry_t *)malloc(sizeof(lcas_db_entry_t));
    }
    if (!plist)
    {
        lcas_log(0,"lcas.mod-lcas_db_fill_entry(): error creating new list entry\n");
        return NULL;
    }
    plist->next=NULL;

    if (entry->pluginname != NULL)
    {
        strncpy(plist->pluginname,entry->pluginname,LCAS_MAXPATHLEN);
        (plist->pluginname)[LCAS_MAXPATHLEN]=NUL;
    }
    else
        strncpy(plist->pluginname,"",LCAS_MAXPATHLEN);

    if (entry->pluginargs != NULL)
    {
        strncpy(plist->pluginargs,entry->pluginargs,LCAS_MAXARGSTRING);
        (plist->pluginargs)[LCAS_MAXARGSTRING]=NUL;
    }
    else
        strncpy(plist->pluginargs,"",LCAS_MAXARGSTRING);

    return plist;
}

static int lcas_db_parse_line(
        char * line,
        lcas_db_entry_t ** entry
)
{
    char *            var_val_pairs[MAXPAIRS];
    char *            var;
    char *            val;
    int               ipair;
    int               no_pairs;
    size_t            len;
    lcas_db_entry_t * tmp_entry=NULL;

    /* Check arguments */
    if ((line == NULL) || (*entry != NULL))
    {
        lcas_log(0,"lcas.mod-lcas_db_parse_line(): something wrong with arguments\n");
        goto error;
    }

    /* Skip over leading whitespace */
    line += strspn(line, WHITESPACE_CHARS);

    /* Check for comment at start of line and ignore line if present */
    if (strchr(COMMENT_CHARS, *line) != NULL) 
    {
        /* Ignore line, return NULL entry. */
        *entry=NULL;
        return 1;
    }

    /* Check for empty line */
    if (*line == NUL)
    {
        /* Empty line, return NULL entry. */
        *entry=NULL;
        return 1;
    }

    /* Look for variable-value pairs by checking the PAIR_SEP_CHARS */
    ipair=0;
    len=0;
    while (*line != NUL)
    {
        len=strcspn(line, PAIR_SEP_CHARS);
        if (len > 0)
        {
            var_val_pairs[ipair] = line;
            ipair++;
            line+=len;
            if (*line == NUL)
            {
                /* probably end of line */
                continue;
            }
            if (strchr(PAIR_SEP_CHARS, *line) != NULL)
            {
                *line=NUL;
                line += 1;
            }
        }
        else
        {
            /* len = 0, so *line=PAIR_SEP_CHARS */
            line += 1;
        }
        line += strspn(line, WHITESPACE_CHARS);
    }
    no_pairs=ipair;
    if (no_pairs)
    {
        tmp_entry=malloc(sizeof(*tmp_entry));
        if (tmp_entry == NULL)
        {
            lcas_log(0,"lcas.mod-lcas_db_parse_line(): error allocating memory\n");
            goto error;
        }

        for (ipair=0; ipair < no_pairs; ipair++)
        {
            int rc=0;
            lcas_log_debug(3,"pair %d:%s-endpair\n",ipair, var_val_pairs[ipair]);
            rc=lcas_db_parse_pair(var_val_pairs[ipair], &var, &val);
            if (! rc)
            {
                /* error parsing variable-value pair */
                lcas_log(0,"lcas.mod-lcas_db_parse_line(): error parsing variable-value pair\n");
                goto error;
            }
            lcas_log_debug(3,"var: %s, value: %s\n",var,val);

            if (strncmp(var,"pluginname",strlen("pluginname")) == 0)
            {
                /* found plugin name */
                strncpy(tmp_entry->pluginname,val,LCAS_MAXPATHLEN);
                (tmp_entry->pluginname)[LCAS_MAXPATHLEN]=NUL;
            }
            else if (strncmp(var,"pluginargs",strlen("pluginargs")) == 0)
            {
                /* found plugin database */
                strncpy(tmp_entry->pluginargs,val,LCAS_MAXARGSTRING);
                (tmp_entry->pluginargs)[LCAS_MAXARGSTRING]=NUL;
            }
            else
            {
                /* unknown option: do nothing */
            }
        }
    }

    /* succes */
    *entry=tmp_entry;
    return 1;

  error:
    if (tmp_entry != NULL) free(tmp_entry);
    return 0;
}

static int lcas_db_parse_pair(
        char * pair,
        char ** pvar,
        char ** pval
)
{
    int    len;
    char * var;
    char * val;

    if (pair == NULL)
    {
        lcas_log(0,"lcas.mod-lcas_db_parse_pair(): cannot parse empty pair\n");
        return 0;
    }

    /* Skip over leading whitespace */
    pair += strspn(pair, WHITESPACE_CHARS);
    if (*pair == NUL)
    {
        lcas_log(0,"lcas.mod-lcas_db_parse_pair(): cannot parse empty pair\n");
        return 0;
    }

    var=pair;
    len=strcspn(pair, VARVAL_SEP_CHARS);
    pair+=len;
    if (*pair == NUL)
    {
        /* Cannot find '=' */
        lcas_log(0,"lcas.mod-lcas_db_parse_pair(): cannot find =\n");
        return 0;
    }

    if (strchr(VARVAL_SEP_CHARS, *pair) != NULL)
    {
        /* Found ' var =' and replace '=' with NUL*/
        *pair=NUL;
        if (! lcas_db_parse_string(&var))
        {
            /* error parsing variable name */
            return 0;
        }
        pair+=1;
        if (*pair==NUL)
        {
            /* No value found */
/*            val=NULL; */
            val=pair;
            *pvar=var;
            *pval=val;
            return 1;
        }
        else
        {
            /* Skip over leading whitespace */
            pair += strspn(pair, WHITESPACE_CHARS);
            if (*pair == NUL)
            {
                /* No value found */
/*                val=NULL; */
                val=pair;
                *pvar=var;
                *pval=val;
                return 1;
            }
            val=pair;
            if (! lcas_db_parse_string(&val))
            {
                /* error parsing value */
                return 0;
            }
        }
    }
    else
    {
        /* Cannot find '=' */
        lcas_log(0,"lcas.mod-lcas_db_parse_pair(): cannot find =\n");
        return 0;
    }

    /* success */
    *pvar=var;
    *pval=val;
    return 1;
}

static int lcas_db_parse_string(
        char ** pstring
)
{
    char * end;
    char * string;

    string=*pstring;

    if (*string==NUL)
    {
        lcas_log(0,"lcas.mod-lcas_db_parse_string(): error parsing null string\n");
        return 0;
    }

    /* Is string quoted ? */
    if (strchr(QUOTING_CHARS, *string) != NULL)
    {
        /*
         * Yes, skip over opening quote and look for unescaped
         * closing double quote
         */
        string++;
        end=string;
        do
        {
            end += strcspn(end, QUOTING_CHARS);
            if (*end == NUL)
            {
                lcas_log(0,"lcas.mod-lcas_db_parse_string(): missing closing quote\n");
                return 0; /* Missing closing quote */
            }

            /* Make sure it's not escaped */
        }
        while (strchr(ESCAPING_CHARS, *(end - 1)) != NULL);
    }
    else
    {
        end = string + strcspn(string, WHITESPACE_CHARS);
    }
    *end=NUL;
    *pstring=string;

    return 1;
}

/******************************************************************************
    Function: lcas_db_clean_list
    documentation in _lcas_db_read.h
******************************************************************************/
int lcas_db_clean_list(
        lcas_db_entry_t ** list
)
{
    lcas_db_entry_t * entry;

    entry=*list;
    while (entry)
    {
        lcas_db_entry_t * next_entry;
        lcas_log_debug(2,"cleaning db entry for module %s\n",entry->pluginname);
        next_entry=entry->next;
        free(entry);
        entry=next_entry;
    }
    *list=entry=NULL;
    return 0;
}

/******************************************************************************
    Function: lcas_db_clean
    documentation in _lcas_db_read.h
******************************************************************************/
int lcas_db_clean()
{
    if(lcas_db_clean_list(&lcas_db_list) != 0)
    {
        lcas_log(0,"lcas.mod-lcas_db_clean() error: could not clean list\n");
        return 1;
    }
    return 0;
}

/******************************************************************************
CVS Information:
    $Source: /cvs/fabric_mgt/gridification/lcas/src/lcas_db_read.c,v $
    $Date: 2003/08/15 13:24:35 $
    $Revision: 2.8 $
    $Author: martijn $
******************************************************************************/

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