pptpd/configfile.c

/*
 * configfile.c
 *
 * Methods for accessing the PPTPD config file and searching for
 * PPTPD keywords.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

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

#include "defaults.h"
#include "configfile.h"
#include "our_syslog.h"

/* Local function prototypes */
static FILE *open_config_file(char *filename);
static void close_config_file(FILE * file);

/*
 * read_config_file
 *
 * This method opens up the file specified by 'filename' and searches
 * through the file for 'keyword'. If 'keyword' is found any string
 * following it is stored in 'value'.
 *
 * args: filename (IN) - config filename
 *       keyword (IN) - word to search for in config file
 *       value (OUT) - value of keyword
 *
 * retn: -1 on error, 0 if keyword not found, 1 on value success
 */
int read_config_file(char *filename, char *keyword, char *value)
{
        FILE *in;
        int len = 0, keyword_len = 0;
        int foundit = 0;

        char *buff_ptr;
        char buffer[MAX_CONFIG_STRING_SIZE];

        *value = '\0';
        buff_ptr = buffer;
        keyword_len = strlen(keyword);

        in = open_config_file(filename);
        if (in == NULL) {
                /* Couldn't find config file, or permission denied */
                return -1;
        }
        while ((fgets(buffer, MAX_CONFIG_STRING_SIZE - 1, in)) != NULL) {
                /* ignore long lines */
                if (buffer[(len = strlen(buffer)) - 1] != '\n') {
                        if (len >= MAX_CONFIG_STRING_SIZE - 2) {
                                syslog(LOG_ERR, "Long config file line ignored.");
                                char *p;
                                do
                                        p = fgets(buffer, MAX_CONFIG_STRING_SIZE - 1, in);
                                while (p && buffer[strlen(buffer) - 1] != '\n');
                                continue;
                        }
                } else {
                        len--;                  /* For the NL at the end */
                }

                while (--len >= 0)
                        if (buffer[len] != ' ' && buffer[len] != '\t')
                                break;

                len++;
                buffer[len] = '\0';

                buff_ptr = buffer;

                /* Short-circuit blank lines and comments */
                if (!len || *buff_ptr == '#')
                        continue;

                /* Non-blank lines starting with a space are an error */

                if (*buff_ptr == ' ' || *buff_ptr == '\t') {
                        syslog(LOG_ERR, "Config file line starts with a space: %s", buff_ptr);
                        continue;
                }

                /* At this point we have a line trimmed for trailing spaces. */
                /* Now we need to check if the keyword matches, and if so */
                /* then get the value (if any). */

                /* Check if it's the right keyword */

                do {
                        if (*buff_ptr == ' ' || *buff_ptr == '\t')
                                break;
                } while (*++buff_ptr);

                len = buff_ptr - buffer;
                if (len == keyword_len && !strncmp(buffer, keyword, len)) {
                        foundit++;
                        break;
                }
        }

        close_config_file(in);

        if (foundit) {
                /* Right keyword, now get the value (if any) */

                do {
                        if (*buff_ptr != ' ' && *buff_ptr != '\t')
                                break;
                        
                } while (*++buff_ptr);

                strcpy(value, buff_ptr);
                return 1;
        } else {
                /* didn't find it - better luck next time */
                return 0;
        }
}

/*
 * open_config_file
 *
 * Opens up the PPTPD config file for reading.
 *
 * args: filename - the config filename (eg. '/etc/pptpd.conf')
 *
 * retn: NULL on error, file descriptor on success
 *
 */
static FILE *open_config_file(char *filename)
{
        FILE *in;
        static int first = 1;

        if ((in = fopen(filename, "r")) == NULL) {
                /* Couldn't open config file */
                if (first) {
                        perror(filename);
                        first = 0;
                }
                return NULL;
        }
        return in;
}

/*
 * close_config_file
 *
 * Closes the PPTPD config file descriptor
 *
 */
static void close_config_file(FILE * in)
{
        fclose(in);
}