modfetch/modules/os.c

/* OS - operating system module for modfetch
 *
 * author: jacekpoz
 * 09 Feb 2024
 */

#include <mod.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>

static const semver _version = {
    .major = 0,
    .minor = 1,
    .patch = 0,
};

semver version(void) { return _version; }
const char *name(void) { return "os"; }

uint8_t init(semver api_ver, char **config) {
    if (!sveq(api_ver, API_VERSION)) {
        return MFERR_APIVER;
    }

    (void)config;

    return 0;
}

const char *get(void) {
    char *ret;

    FILE *os_release = fopen("/etc/os-release", "r");

    if (os_release == NULL) {
        fprintf(stderr, "error: failed opening /etc/os-release\n");
        exit(EXIT_FAILURE);
    }

    size_t len = 0;
    ssize_t read;
    char *line = NULL;

    char *name = NULL;
    const char *name_label = "PRETTY_NAME=";
    const size_t name_label_len = strlen(name_label);

    while ((read = getline(&line, &len, os_release)) != -1) {
        if (strncmp(line, name_label, name_label_len) != 0) {
            continue;
        }
        // + 1 because of "
        line += name_label_len + 1;
        const size_t new_len = strlen(line);
        // the ending "
        line[new_len - 2] = '\0';
        name = line;
        break;
    }

    fclose(os_release);

    if (name == NULL) {
        name = "Unknown";
    }

    if (asprintf(&ret, "OS: %s", name) < 0) {
        fprintf(stderr, "error: failed formatting string (this shouldn't happen)");
        exit(EXIT_FAILURE);
    }

    return ret;
}