Check all env vars and suggest alternatives for misspelled keys

.github/.codespellignore

@@ -6,3 +6,4 @@ doubleclick
 requestor
 requestors
 punycode
+bitap

src/config/CMakeLists.txt

@@ -15,12 +15,16 @@ set(sources
         config.h
         dnsmasq_config.c
         dnsmasq_config.h
+        env.c
+        env.h
         inotify.c
         inotify.h
         legacy_reader.c
         legacy_reader.h
         password.c
         password.h
+        suggest.c
+        suggest.h
         setupVars.c
         setupVars.h
         toml_writer.c

src/config/cli.c

@@ -22,6 +22,17 @@
 #include "config/password.h"
 // check_capability()
 #include "capabilities.h"
+// suggest_closest_conf_key()
+#include "config/suggest.h"
+
+enum exit_codes {
+	OKAY = 0,
+	FAIL = 1,
+	VALUE_INVALID = 2,
+	DNSMASQ_TEST_FAILED = 3,
+	KEY_UNKNOWN = 4,
+	ENV_VAR_FORCED = 5,
+} __attribute__((packed));
 
 // Read a TOML value from a table depending on its type
 static bool readStringValue(struct conf_item *conf_item, const char *value, struct config *newconf)
@@ -402,7 +413,7 @@ int set_config_from_CLI(const char *key, const char *value)
 		{
 			log_err("Config option %s is read-only (set via environmental variable)", key);
 			free_config(&newconf);
-			return 5;
+			return ENV_VAR_FORCED;
 		}
 
 		// This is the config option we are looking for
@@ -418,16 +429,22 @@ int set_config_from_CLI(const char *key, const char *value)
 	// Check if we found the config option
 	if(new_item == NULL)
 	{
-		log_err("Unknown config option: %s", key);
+		unsigned int N = 0;
+		char **matches = suggest_closest_conf_key(false, key, &N);
+		log_err("Unknown config option %s, did you mean:", key);
+		for(unsigned int i = 0; i < N; i++)
+			log_err(" - %s", matches[i]);
+		free(matches);
+
 		free_config(&newconf);
-		return 4;
+		return KEY_UNKNOWN;
 	}
 
 	// Parse value
 	if(!readStringValue(new_item, value, &newconf))
 	{
 		free_config(&newconf);
-		return 2;
+		return VALUE_INVALID;
 	}
 
 	// Check if value changed compared to current value
@@ -447,7 +464,7 @@ int set_config_from_CLI(const char *key, const char *value)
 				// Test failed
 				log_debug(DEBUG_CONFIG, "Config item %s: dnsmasq config test failed", conf_item->k);
 				free_config(&newconf);
-				return 3;
+				return DNSMASQ_TEST_FAILED;
 			}
 		}
 		else if(conf_item == &config.dns.hosts)
@@ -475,7 +492,7 @@ int set_config_from_CLI(const char *key, const char *value)
 
 	putchar('\n');
 	writeFTLtoml(false);
-	return EXIT_SUCCESS;
+	return OKAY;
 }
 
 int get_config_from_CLI(const char *key, const bool quiet)
@@ -534,14 +551,20 @@ int get_config_from_CLI(const char *key, const bool quiet)
 	// Check if we found the config option
 	if(conf_item == NULL)
 	{
-		log_err("Unknown config option: %s", key);
-		return 2;
+		unsigned int N = 0;
+		char **matches = suggest_closest_conf_key(false, key, &N);
+		log_err("Unknown config option %s, did you mean:", key);
+		for(unsigned int i = 0; i < N; i++)
+			log_err(" - %s", matches[i]);
+		free(matches);
+
+		return KEY_UNKNOWN;
 	}
 
 	// Use return status if this is a boolean value
 	// and we are in quiet mode
 	if(quiet && conf_item != NULL && conf_item->t == CONF_BOOL)
-		return conf_item->v.b ? EXIT_SUCCESS : EXIT_FAILURE;
+		return conf_item->v.b ? OKAY : FAIL;
 
-	return EXIT_SUCCESS;
+	return OKAY;
 }

src/config/config.c

@@ -29,6 +29,8 @@
 #include "api/api.h"
 // exit_code
 #include "signals.h"
+// getEnvVars()
+#include "config/env.h"
 // sha256sum()
 #include "files.h"
 
@@ -1318,17 +1320,24 @@ void initConfig(struct config *conf)
 		// Parse and split paths
 		conf_item->p = gen_config_path(conf_item->k, '.');
 
-		// Verify all config options are defined above
-		if(!conf_item->p || !conf_item->k || !conf_item->h)
-		{
-			log_err("Config option %u/%u is not set!", i, (unsigned int)CONFIG_ELEMENTS);
-			continue;
-		}
+		// Initialize environment variable name
+		// Allocate memory for config key + prefix (sizeof includes the trailing '\0')
+		const size_t envkey_size = strlen(conf_item->k) + sizeof(FTLCONF_PREFIX);
+		conf_item->e = calloc(envkey_size, sizeof(char));
 
-		// Verify that all config options have a type
-		if(conf_item->t == 0)
+		// Build env key to look for
+		strcpy(conf_item->e, FTLCONF_PREFIX);
+		strcat(conf_item->e, conf_item->k);
+
+		// Replace all "." by "_" as this is the convention used in v5.x and earlier
+		for(unsigned int j = 0; j < envkey_size - 1; j++)
+			if(conf_item->e[j] == '.')
+				conf_item->e[j] = '_';
+
+		// Verify all config options are defined above
+		if(!conf_item->p || !conf_item->k || !conf_item->h || !conf_item->e || conf_item->t == 0)
 		{
-			log_err("Config option %s has no type!", conf_item->k);
+			log_err("Config option %u/%u is not fully configured!", i, (unsigned int)CONFIG_ELEMENTS);
 			continue;
 		}
 
@@ -1381,7 +1390,10 @@ bool readFTLconf(struct config *conf, const bool rewrite)
 	// Initialize config with default values
 	initConfig(conf);
 
-	// First try to read TOML config file
+	// First, read the environment
+	getEnvVars();
+
+	// Try to read TOML config file
 	// If we cannot parse /etc/pihole.toml (due to missing or invalid syntax),
 	// we try to read the rotated files in /etc/pihole/config_backup starting at
 	// the most recent one and going back in time until we find a valid config

src/config/config.h

@@ -102,6 +102,7 @@ enum conf_type {
 struct conf_item {
 	const char *k;        // item Key
 	char **p;             // item Path
+	char *e;              // item Environment variable
 	const char *h;        // Help text / description
 	cJSON *a;             // JSON array or object of Allowed values (where applicable)
 	enum conf_type t;     // variable Type