save.c

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>

#include "save.h"
#include "utils.h"
#include "xdg.h"

save read_save(bool wipe) {
    char *confpath = xdg_config_dir("cnetstat");

    char tmp[strlen(confpath) + strlen("/saved") + 1];
    sprintf(tmp, "%s/saved", confpath);
    FILE *savef = fopen(tmp, "r");

    free(confpath);

    if(!savef) {
        save sv = {
            .rxbytes = 0,
            .txbytes = 0,
            .boot_id = get_boot_id(),
            .rxbytes_boot = 0,
            .txbytes_boot = 0
        };
        return sv;
    }

    int ret;
    save sv;
    // len(boot_id) = 36 + 1
    sv.boot_id = malloc(37);
    if((ret = fscanf(savef, "%zd %zd %36s %zd %zd", &sv.rxbytes, &sv.txbytes, sv.boot_id, &sv.rxbytes_boot, &sv.txbytes_boot)) != 5) {
        eprintf("Failed to read saved stats: %s\n", ret < 0 ? strerror(errno) : "Invalid format");
        exit(EXIT_FAILURE);
    }

    if(wipe) {
        sv.rxbytes=0;
        sv.txbytes=0;
        sv.txbytes_boot=0;
        sv.rxbytes_boot=0;
    }

    if(fclose(savef)) {
        perror("Failed to close save file");
        exit(EXIT_FAILURE);
    }
    return sv;
}
void write_save(save sv) {
    // FIXME: only call this once
    char* confpath = xdg_config_dir("cnetstat");
    if(mkdirp(confpath, 0777) < 0) {
        perror("Could not create config directory");
        exit(EXIT_FAILURE);
    }

    char tmp[strlen(confpath) + strlen("/saved") + 1];
    sprintf(tmp, "%s/saved", confpath);
    FILE* savef = fopen(tmp, "w+");

    if(!savef) {
        perror("Could not open save file");
        exit(EXIT_FAILURE);
    }

    free(confpath);

    int ret;
    if ((ret = fprintf(savef, "%zd %zd %s %zd %zd", sv.rxbytes, sv.txbytes,
                    sv.boot_id, sv.rxbytes_boot, sv.txbytes_boot)) < 0) {
        eprintf("Could not write to save file: %s\n", strerror(errno));
        exit(EXIT_FAILURE);
    }

    if(fclose(savef)) {
        perror("Failed to close save file");
        exit(EXIT_FAILURE);
    }
}