Feat: load env vars

src/config.c

@@ -0,0 +1,120 @@
+#include <errno.h>
+#include <limits.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "config.h"
+#include "log.h"
+
+static int load_env_str(const char *env_name, char **out, int unset) {
+    const char *env_var = getenv(env_name);
+    if (!env_var || env_var[0] == '\0') {
+        log_error("Missing required env var %s", env_name);
+        return -1;
+    }
+    *out = strdup(env_var);
+    if (!*out) { log_error("Memory allocation failed"); return -1; }
+    if (unset) unsetenv(env_name);
+    return 0;
+}
+
+static int load_env_int(
+    const char *env_name,
+    int *out,
+    int min,
+    int max,
+    int fallback
+) {
+    const char *env_var = getenv(env_name);
+    if (!env_var || env_var[0] == '\0') { *out = fallback; return 0; }
+
+    char *end;
+    errno = 0;
+    long parsed = strtol(env_var, &end, 10);
+
+    if (errno != 0 || *end != '\0') {
+        log_error("%s needs to be an integer", env_name);
+        return -1;
+    }
+    if (parsed < min || parsed > max) {
+        log_error("%s needs to be within range (%d-%d)", env_name, min, max);
+        return -1;
+    }
+    *out = (int)parsed;
+    return 0;
+}
+
+static int load_env_strs(
+    const char *env_name,
+    char ***out,
+    int *count,
+    int max_str_len
+) {
+    char *str = NULL;
+    if (load_env_str(env_name, &str, 0)) return -1;
+
+    *count = 1
+    for (char *p = str; *p; p++)
+        if (*p == ',') (*count)++;
+
+    for (char *start = str, *p = str; ; p++) {
+        if (*p == ',' || *p == '\0') {
+            if ((int)(p - start) > max_str_len) {
+                log_error("'%.*s' in %s exceeds max length (%d)",
+                        (int)(p - start), start, env_name, max_str_len);
+                free(str);
+                return -1;
+            }
+
+            if (*p == '\0') break;
+            start = p + 1;
+        }
+    }
+
+    char **arr = malloc(*count * sizeof(char *));
+    if (!arr) { log_error("Memory allocation failed"); free(str); return -1; }
+
+    int i = 0
+    char *token = strtok(str, ",");
+    while (token) {
+        arr[i++] = strdup(token);
+        token = strtok(NULL, ",");
+    }
+
+    free(str);
+    *out = arr;
+    return 0;
+}
+
+int config_load(Config *cfg) {
+    if (load_env_str(ENV_GANDI_TOKEN, &cfg->api_token, 1)) return -1;
+
+    if (load_env_str(ENV_DNS_KEEPER_DOMAIN, &cfg->dns_keeper_domain, 0)) return -1;
+    if (load_env_str(ENV_DNS_KEEPER_RECORD, &cfg->dns_keeper_record, 0)) return -1;
+    if (strlen(cfg->dns_keeper_record) + 1 +  strlen(cfg->dns_keeper_domain) > CONFIG_MAX_DOMAIN_LEN) {
+        log_error("%s.%s exceeds max FQDN length (%d)",
+                ENV_SELF_RECORD, ENV_SELF_DOMAIN, CONFIG_MAX_FQDN_LEN);
+        return -1;
+    }
+
+    if (load_env_int(ENV_DNS_KEEPER_PORT, &cfg->dns_keeper_port,
+            1, 65535, DEFAULT_DNS_KEEPER_PORT)) return -1;
+    if (load_env_int(ENV_POLL_INTERVAL, &cfg->poll_interval,
+            1, INT_MAX, DEFAULT_POLL_INTERVAL)) return -1;
+    
+    if (load_env_strs(ENV_DOMAINS, &cfg->domains, &cfg->domain_count, CONFIG_MAX_DOMAIN_LEN)) return -1;
+
+    return 0;
+}
+
+void config_free(Config *cfg) {
+    if (cfg->domains) {
+        for (int i = 0; i < cfg->domain_count; i++) {
+            free(cfg->domains[i]);
+        }
+        free(cfg->domains);
+        cfg->domains = NULL;
+        cfg->domain_count = 0;
+    }
+}

src/config.h

@@ -0,0 +1,28 @@
+#ifndef CONFIG_H
+#define CONFIG_H
+
+#define ENV_GANDI_TOKEN       "GANDI_API_TOKEN"
+#define ENV_DOMAINS           "DOMAINS"
+#define ENV_DNS_KEEPER_PORT   "DNS_KEEPER_PORT"
+#define ENV_DNS_KEEPER_DOMAIN "DNS_KEEPER_DOMAIN"
+#define ENV_DNS_KEEPER_RECORD "DNS_KEEPER_RECORD"
+#define ENV_POLL_INTERVAL     "POLL_INTERVAL"
+
+#define DEFAULT_DNS_KEEPER_PORT 65535u
+#define DEFAULT_POLL_INTERVAL 5u
+#define CONFIG_MAX_DOMAIN_LEN 253u /* RFC 1035 max FQDN length */
+
+typedef struct {
+    char  *api_token;
+    char  *dns_keeper_domain;
+    char  *dns_keeper_record;
+    int    dns_keeper_port;
+    int    poll_interval;
+    char **domains;
+    int    domain_count;
+} Config;
+
+int  config_load(Config *cfg);
+void config_free(Config *cfg);
+
+#endif /* CONFIG_H */