src/server/dial_data.c

/*
 * Functions related to storing/retrieving and manipulating DIAL data.
 */
#include "dial_data.h"
#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

/**
 * Returns the path where data is stored for the given app.
 */
static char* getAppPath(char app_name[]) {
    size_t name_size = strlen(app_name) + sizeof(DIAL_DATA_DIR) + 1;
    char* filename = (char*) malloc(name_size);
    filename[0] = 0;
    strncat(filename, DIAL_DATA_DIR, name_size);
    strncat(filename, app_name, name_size - sizeof(DIAL_DATA_DIR));
    return filename;
}

void store_dial_data(char app_name[], DIALData *data) {
    char* filename = getAppPath(app_name);
    FILE *f = fopen(filename, "w");
    if (f == NULL) {
        printf("Cannot open DIAL data output file: %s\n", filename);
        exit(1);
    }
    for (DIALData *first = data; first != NULL; first = first->next) {
        fprintf(f, "%s %s\n", first->key, first->value);
    }
    fclose(f);
}

DIALData *retrieve_dial_data(char *app_name) {
    char* filename = getAppPath(app_name);
    FILE *f = fopen(filename, "r");
    if (f == NULL) {
        return NULL; // no dial data found, that's fine
    }
    DIALData *result = NULL;
    char key[256];
    char value[256];
    while (fscanf(f, "%255s %255s\n", key, value) != EOF) {
        DIALData *newNode = (DIALData *) malloc(sizeof(DIALData));
        newNode->key = strdup(key);
        newNode->value = strdup(value);
        newNode->next = result;
        result = newNode;
    }
    fclose(f);
    return result;
}