X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=src%2Fconf.c;h=65ff2272ef68e50e293ad23cda5d4045315b3d7e;hb=f31267783fccb4e17d914c64243b0cba4e5632c4;hp=1d9efb646698efbbdaa9fb50241772dd16afb0c7;hpb=627f7c22b447bd464b536cd016278545674df93d;p=meshlink

diff --git a/src/conf.c b/src/conf.c
index 1d9efb64..65ff2272 100644
--- a/src/conf.c
+++ b/src/conf.c
@@ -1,9 +1,6 @@
 /*
-    conf.c -- configuration code
-    Copyright (C) 1998 Robert van der Meulen
-                  1998-2002 Ivo Timmermans <ivo@o2w.nl>
-                  2000-2002 Guus Sliepen <guus@sliepen.eu.org>
-		  2000 Cris van Pelt <tribbel@arise.dhs.org>
+    econf.c -- configuration code
+    Copyright (C) 2018 Guus Sliepen <guus@meshlink.io>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -15,609 +12,951 @@
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
 
-    You should have received a copy of the GNU General Public License
-    along with this program; if not, write to the Free Software
-    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
-
-    $Id: conf.c,v 1.9.4.57 2002/06/21 10:11:12 guus Exp $
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
-#include "config.h"
-
-#include <ctype.h>
-#include <errno.h>
-#include <netdb.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <syslog.h>
-#include <sys/stat.h>
+#include "system.h"
+#include <assert.h>
 #include <sys/types.h>
-#include <unistd.h>
-#include <syslog.h>
-#include <string.h>
-
-#include <xalloc.h>
-#include <utils.h> /* for cp */
-#include <avl_tree.h>
+#include <utime.h>
 
 #include "conf.h"
-#include "netutl.h" /* for str2address */
+#include "crypto.h"
+#include "logger.h"
+#include "meshlink_internal.h"
+#include "xalloc.h"
+#include "packmsg.h"
+
+/// Generate a path to the main configuration file.
+static void make_main_path(meshlink_handle_t *mesh, const char *conf_subdir, char *path, size_t len) {
+	assert(conf_subdir);
+	assert(path);
+	assert(len);
+
+	snprintf(path, len, "%s" SLASH "%s" SLASH "meshlink.conf", mesh->confbase, conf_subdir);
+}
 
-#include "system.h"
+/// Generate a path to a host configuration file.
+static void make_host_path(meshlink_handle_t *mesh, const char *conf_subdir, const char *name, char *path, size_t len) {
+	assert(conf_subdir);
+	assert(name);
+	assert(path);
+	assert(len);
+
+	snprintf(path, len, "%s" SLASH "%s" SLASH "hosts" SLASH "%s", mesh->confbase, conf_subdir, name);
+}
+
+/// Generate a path to an unused invitation file.
+static void make_invitation_path(meshlink_handle_t *mesh, const char *conf_subdir, const char *name, char *path, size_t len) {
+	assert(conf_subdir);
+	assert(name);
+	assert(path);
+	assert(len);
+
+	snprintf(path, len, "%s" SLASH "%s" SLASH "invitations" SLASH "%s", mesh->confbase, conf_subdir, name);
+}
+
+/// Generate a path to a used invitation file.
+static void make_used_invitation_path(meshlink_handle_t *mesh, const char *conf_subdir, const char *name, char *path, size_t len) {
+	assert(conf_subdir);
+	assert(name);
+	assert(path);
+	assert(len);
+
+	snprintf(path, len, "%s" SLASH "%s" SLASH "invitations" SLASH "%s.used", mesh->confbase, conf_subdir, name);
+}
+
+/// Remove a directory recursively
+static void deltree(const char *dirname) {
+	assert(dirname);
 
-avl_tree_t *config_tree;
+	DIR *d = opendir(dirname);
 
-int debug_lvl = 0;
-int pingtimeout = 0;             /* seconds before timeout */
-char *confbase = NULL;           /* directory in which all config files are */
-char *netname = NULL;            /* name of the vpn network */
+	if(d) {
+		struct dirent *ent;
 
-int config_compare(config_t *a, config_t *b)
-{
-  int result;
+		while((ent = readdir(d))) {
+			if(ent->d_name[0] == '.') {
+				continue;
+			}
 
-  result = strcasecmp(a->variable, b->variable);
+			char filename[PATH_MAX];
+			snprintf(filename, sizeof(filename), "%s" SLASH "%s", dirname, ent->d_name);
 
-  if(result)
-    return result;
+			if(unlink(filename)) {
+				deltree(filename);
+			}
+		}
 
-  result = a->line - b->line;
+		closedir(d);
+	}
 
-  if(result)
-    return result;
-  else
-    return strcmp(a->file, b->file);
+	rmdir(dirname);
 }
 
-void init_configuration(avl_tree_t **config_tree)
-{
-cp
-  *config_tree = avl_alloc_tree((avl_compare_t)config_compare, (avl_action_t)free_config);
-cp
+static bool sync_path(const char *pathname) {
+	assert(pathname);
+
+	int fd = open(pathname, O_RDONLY);
+
+	if(fd < 0) {
+		logger(NULL, MESHLINK_ERROR, "Failed to open %s: %s\n", pathname, strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
+
+	if(fsync(fd)) {
+		logger(NULL, MESHLINK_ERROR, "Failed to sync %s: %s\n", pathname, strerror(errno));
+		close(fd);
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
+
+	if(close(fd)) {
+		logger(NULL, MESHLINK_ERROR, "Failed to close %s: %s\n", pathname, strerror(errno));
+		close(fd);
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
+
+	return true;
 }
 
-void exit_configuration(avl_tree_t **config_tree)
-{
-cp
-  avl_delete_tree(*config_tree);
-  *config_tree = NULL;
-cp
+/// Try decrypting the main configuration file from the given sub-directory.
+static bool main_config_decrypt(meshlink_handle_t *mesh, const char *conf_subdir) {
+	assert(mesh->config_key);
+	assert(mesh->confbase);
+	assert(conf_subdir);
+
+	config_t config;
+
+	if(!main_config_read(mesh, conf_subdir, &config, mesh->config_key)) {
+		logger(mesh, MESHLINK_ERROR, "Could not read main configuration file");
+		return false;
+	}
+
+	packmsg_input_t in = {config.buf, config.len};
+
+	uint32_t version = packmsg_get_uint32(&in);
+	config_free(&config);
+
+	return version == MESHLINK_CONFIG_VERSION;
 }
 
-config_t *new_config(void)
-{
-  config_t *cfg;
-cp
-  cfg = (config_t *)xmalloc_and_zero(sizeof(*cfg));
+/// Create a fresh configuration directory
+bool config_init(meshlink_handle_t *mesh, const char *conf_subdir) {
+	assert(conf_subdir);
 
-  return cfg;
+	if(!mesh->confbase) {
+		return true;
+	}
+
+	if(mkdir(mesh->confbase, 0700) && errno != EEXIST) {
+		logger(mesh, MESHLINK_DEBUG, "Could not create directory %s: %s\n", mesh->confbase, strerror(errno));
+		return false;
+	}
+
+	char path[PATH_MAX];
+
+	// Create "current" sub-directory in the confbase
+	snprintf(path, sizeof(path), "%s" SLASH "%s", mesh->confbase, conf_subdir);
+	deltree(path);
+
+	if(mkdir(path, 0700)) {
+		logger(mesh, MESHLINK_DEBUG, "Could not create directory %s: %s\n", path, strerror(errno));
+		return false;
+	}
+
+	make_host_path(mesh, conf_subdir, "", path, sizeof(path));
+
+	if(mkdir(path, 0700)) {
+		logger(mesh, MESHLINK_DEBUG, "Could not create directory %s: %s\n", path, strerror(errno));
+		return false;
+	}
+
+	make_invitation_path(mesh, conf_subdir, "", path, sizeof(path));
+
+	if(mkdir(path, 0700)) {
+		logger(mesh, MESHLINK_DEBUG, "Could not create directory %s: %s\n", path, strerror(errno));
+		return false;
+	}
+
+	return true;
 }
 
-void free_config(config_t *cfg)
-{
-cp
-  if(cfg->variable)
-    free(cfg->variable);
-  if(cfg->value)
-    free(cfg->value);
-  if(cfg->file)
-    free(cfg->file);
-  free(cfg);
-cp
+/// Wipe an existing configuration directory
+bool config_destroy(const char *confbase, const char *conf_subdir) {
+	assert(conf_subdir);
+
+	if(!confbase) {
+		return false;
+	}
+
+	struct stat st;
+
+	char path[PATH_MAX];
+
+	// Check the presence of configuration base sub directory.
+	snprintf(path, sizeof(path), "%s" SLASH "%s", confbase, conf_subdir);
+
+	if(stat(path, &st)) {
+		if(errno == ENOENT) {
+			return true;
+		} else {
+			logger(NULL, MESHLINK_ERROR, "Cannot stat %s: %s\n", path, strerror(errno));
+			meshlink_errno = MESHLINK_ESTORAGE;
+			return false;
+		}
+	}
+
+	// Remove meshlink.conf
+	snprintf(path, sizeof(path), "%s" SLASH "%s" SLASH "meshlink.conf", confbase, conf_subdir);
+
+	if(unlink(path)) {
+		if(errno != ENOENT) {
+			logger(NULL, MESHLINK_ERROR, "Cannot delete %s: %s\n", path, strerror(errno));
+			meshlink_errno = MESHLINK_ESTORAGE;
+			return false;
+		}
+	}
+
+	snprintf(path, sizeof(path), "%s" SLASH "%s", confbase, conf_subdir);
+	deltree(path);
+	return true;
 }
 
-void config_add(avl_tree_t *config_tree, config_t *cfg)
-{
-cp
-  avl_insert(config_tree, cfg);
-cp
+static bool copytree(const char *src_dir_name, const void *src_key, const char *dst_dir_name, const void *dst_key) {
+	assert(src_dir_name);
+	assert(dst_dir_name);
+
+	char src_filename[PATH_MAX];
+	char dst_filename[PATH_MAX];
+	struct dirent *ent;
+
+	DIR *src_dir = opendir(src_dir_name);
+
+	if(!src_dir) {
+		logger(NULL, MESHLINK_ERROR, "Could not open directory file %s\n", src_dir_name);
+		return false;
+	}
+
+	// Delete if already exists and create a new destination directory
+	deltree(dst_dir_name);
+
+	if(mkdir(dst_dir_name, 0700)) {
+		logger(NULL, MESHLINK_ERROR, "Could not create directory %s\n", dst_filename);
+		return false;
+	}
+
+	while((ent = readdir(src_dir))) {
+		if(ent->d_name[0] == '.') {
+			continue;
+		}
+
+		snprintf(dst_filename, sizeof(dst_filename), "%s" SLASH "%s", dst_dir_name, ent->d_name);
+		snprintf(src_filename, sizeof(src_filename), "%s" SLASH "%s", src_dir_name, ent->d_name);
+
+		if(ent->d_type == DT_DIR) {
+			if(!copytree(src_filename, src_key, dst_filename, dst_key)) {
+				logger(NULL, MESHLINK_ERROR, "Copying %s to %s failed\n", src_filename, dst_filename);
+				return false;
+			}
+
+			if(!sync_path(dst_filename)) {
+				return false;
+			}
+		} else if(ent->d_type == DT_REG) {
+			struct stat st;
+			config_t config;
+
+			if(stat(src_filename, &st)) {
+				logger(NULL, MESHLINK_ERROR, "Could not stat file `%s': %s\n", src_filename, strerror(errno));
+				return false;
+			}
+
+			FILE *f = fopen(src_filename, "r");
+
+			if(!f) {
+				logger(NULL, MESHLINK_ERROR, "Failed to open `%s': %s\n", src_filename, strerror(errno));
+				return false;
+			}
+
+			if(!config_read_file(NULL, f, &config, src_key)) {
+				logger(NULL, MESHLINK_ERROR, "Failed to read `%s': %s\n", src_filename, strerror(errno));
+				fclose(f);
+				return false;
+			}
+
+			if(fclose(f)) {
+				logger(NULL, MESHLINK_ERROR, "Failed to close `%s': %s\n", src_filename, strerror(errno));
+				config_free(&config);
+				return false;
+			}
+
+			f = fopen(dst_filename, "w");
+
+			if(!f) {
+				logger(NULL, MESHLINK_ERROR, "Failed to open `%s': %s", dst_filename, strerror(errno));
+				config_free(&config);
+				return false;
+			}
+
+			if(!config_write_file(NULL, f, &config, dst_key)) {
+				logger(NULL, MESHLINK_ERROR, "Failed to write `%s': %s", dst_filename, strerror(errno));
+				config_free(&config);
+				fclose(f);
+				return false;
+			}
+
+			if(fclose(f)) {
+				logger(NULL, MESHLINK_ERROR, "Failed to close `%s': %s", dst_filename, strerror(errno));
+				config_free(&config);
+				return false;
+			}
+
+			config_free(&config);
+
+			struct utimbuf times;
+			times.modtime = st.st_mtime;
+			times.actime = st.st_atime;
+
+			if(utime(dst_filename, &times)) {
+				logger(NULL, MESHLINK_ERROR, "Failed to utime `%s': %s", dst_filename, strerror(errno));
+				return false;
+			}
+		}
+	}
+
+	closedir(src_dir);
+	return true;
 }
 
-config_t *lookup_config(avl_tree_t *config_tree, char *variable)
-{
-  config_t cfg, *found;
-cp
-  cfg.variable = variable;
-  cfg.file = "";
-  cfg.line = 0;
+bool config_copy(meshlink_handle_t *mesh, const char *src_dir_name, const void *src_key, const char *dst_dir_name, const void *dst_key) {
+	assert(src_dir_name);
+	assert(dst_dir_name);
 
-  found = avl_search_closest_greater(config_tree, &cfg);
+	char src_filename[PATH_MAX];
+	char dst_filename[PATH_MAX];
 
-  if(!found)
-    return NULL;
+	snprintf(dst_filename, sizeof(dst_filename), "%s" SLASH "%s", mesh->confbase, dst_dir_name);
+	snprintf(src_filename, sizeof(src_filename), "%s" SLASH "%s", mesh->confbase, src_dir_name);
+
+	return copytree(src_filename, src_key, dst_filename, dst_key);
+}
 
-  if(strcasecmp(found->variable, variable))
-    return NULL;
+/// Check the presence of the main configuration file.
+bool main_config_exists(meshlink_handle_t *mesh, const char *conf_subdir) {
+	assert(conf_subdir);
 
-  return found;
+	if(!mesh->confbase) {
+		return false;
+	}
+
+	char path[PATH_MAX];
+	make_main_path(mesh, conf_subdir, path, sizeof(path));
+	return access(path, F_OK) == 0;
 }
 
-config_t *lookup_config_next(avl_tree_t *config_tree, config_t *cfg)
-{
-  avl_node_t *node;
-  config_t *found;
-cp
-  node = avl_search_node(config_tree, cfg);
-
-  if(node)
-    {
-      if(node->next)
-        {
-          found = (config_t *)node->next->data;
-          if(!strcasecmp(found->variable, cfg->variable))
-            return found;
-        }
-    }
-
-  return NULL;
+bool config_rename(meshlink_handle_t *mesh, const char *old_conf_subdir, const char *new_conf_subdir) {
+	assert(old_conf_subdir);
+	assert(new_conf_subdir);
+
+	if(!mesh->confbase) {
+		return false;
+	}
+
+	char old_path[PATH_MAX];
+	char new_path[PATH_MAX];
+
+	snprintf(old_path, sizeof(old_path), "%s" SLASH "%s", mesh->confbase, old_conf_subdir);
+	snprintf(new_path, sizeof(new_path), "%s" SLASH "%s", mesh->confbase, new_conf_subdir);
+
+	return rename(old_path, new_path) == 0;
 }
 
-int get_config_bool(config_t *cfg, int *result)
-{
-cp
-  if(!cfg)
-    return 0;
-
-  if(!strcasecmp(cfg->value, "yes"))
-    {
-      *result = 1;
-      return 1;
-    }
-  else if(!strcasecmp(cfg->value, "no"))
-    {
-      *result = 0;
-      return 1;
-    }
-
-  syslog(LOG_ERR, _("\"yes\" or \"no\" expected for configuration variable %s in %s line %d"),
-         cfg->variable, cfg->file, cfg->line);
-
-  return 0;
+bool config_sync(meshlink_handle_t *mesh, const char *conf_subdir) {
+	assert(conf_subdir);
+
+	if(!mesh->confbase) {
+		return true;
+	}
+
+	char path[PATH_MAX];
+	snprintf(path, sizeof(path), "%s" SLASH "%s" SLASH "hosts", mesh->confbase, conf_subdir);
+
+	if(!sync_path(path)) {
+		return false;
+	}
+
+	snprintf(path, sizeof(path), "%s" SLASH "%s", mesh->confbase, conf_subdir);
+
+	if(!sync_path(path)) {
+		return false;
+	}
+
+	return true;
 }
 
-int get_config_int(config_t *cfg, int *result)
-{
-cp
-  if(!cfg)
-    return 0;
+bool meshlink_confbase_exists(meshlink_handle_t *mesh) {
+	if(!mesh->confbase) {
+		return false;
+	}
+
+	bool confbase_exists = false;
+	bool confbase_decryptable = false;
+
+	if(main_config_exists(mesh, "current")) {
+		confbase_exists = true;
+
+		if(mesh->config_key && main_config_decrypt(mesh, "current")) {
+			confbase_decryptable = true;
+		}
+	}
+
+	if(mesh->config_key && !confbase_decryptable && main_config_exists(mesh, "new")) {
+		confbase_exists = true;
 
-  if(sscanf(cfg->value, "%d", result) == 1)
-    return 1;
+		if(main_config_decrypt(mesh, "new")) {
+			if(!config_destroy(mesh->confbase, "current")) {
+				return false;
+			}
 
-  syslog(LOG_ERR, _("Integer expected for configuration variable %s in %s line %d"),
-         cfg->variable, cfg->file, cfg->line);
-  return 0;
+			if(!config_rename(mesh, "new", "current")) {
+				return false;
+			}
+
+			confbase_decryptable = true;
+		}
+	}
+
+	if(mesh->config_key && !confbase_decryptable && main_config_exists(mesh, "old")) {
+		confbase_exists = true;
+
+		if(main_config_decrypt(mesh, "old")) {
+			if(!config_destroy(mesh->confbase, "current")) {
+				return false;
+			}
+
+			if(!config_rename(mesh, "old", "current")) {
+				return false;
+			}
+
+			confbase_decryptable = true;
+		}
+	}
+
+	// Cleanup if current is existing with old and new
+	if(confbase_exists && confbase_decryptable) {
+		config_destroy(mesh->confbase, "old");
+		config_destroy(mesh->confbase, "new");
+	}
+
+	return confbase_exists;
 }
 
-int get_config_string(config_t *cfg, char **result)
-{
-cp
-  if(!cfg)
-    return 0;
+/// Lock the main configuration file.
+bool main_config_lock(meshlink_handle_t *mesh) {
+	if(!mesh->confbase) {
+		return true;
+	}
+
+	char path[PATH_MAX];
+	make_main_path(mesh, "current", path, sizeof(path));
+
+	mesh->conffile = fopen(path, "r");
+
+	if(!mesh->conffile) {
+		logger(NULL, MESHLINK_ERROR, "Cannot not open %s: %s\n", path, strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
 
-  *result = xstrdup(cfg->value);
-  return 1;
+#ifdef FD_CLOEXEC
+	fcntl(fileno(mesh->conffile), F_SETFD, FD_CLOEXEC);
+#endif
+
+#ifdef HAVE_MINGW
+	// TODO: use _locking()?
+#else
+
+	if(flock(fileno(mesh->conffile), LOCK_EX | LOCK_NB) != 0) {
+		logger(NULL, MESHLINK_ERROR, "Cannot lock %s: %s\n", path, strerror(errno));
+		fclose(mesh->conffile);
+		mesh->conffile = NULL;
+		meshlink_errno = MESHLINK_EBUSY;
+		return false;
+	}
+
+#endif
+
+	return true;
+}
+
+/// Unlock the main configuration file.
+void main_config_unlock(meshlink_handle_t *mesh) {
+	if(mesh->conffile) {
+		fclose(mesh->conffile);
+		mesh->conffile = NULL;
+	}
 }
 
-int get_config_address(config_t *cfg, struct addrinfo **result)
-{
-  struct addrinfo *ai;
-cp
-  if(!cfg)
-    return 0;
+/// Read a configuration file from a FILE handle.
+bool config_read_file(meshlink_handle_t *mesh, FILE *f, config_t *config, const void *key) {
+	assert(f);
+
+	long len;
+
+	if(fseek(f, 0, SEEK_END) || !(len = ftell(f)) || fseek(f, 0, SEEK_SET)) {
+		logger(mesh, MESHLINK_ERROR, "Cannot get config file size: %s\n", strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
 
-  ai = str2addrinfo(cfg->value, NULL, 0);
+	uint8_t *buf = xmalloc(len);
 
-  if(ai)
-    {
-      *result = ai;
-      return 1;
-    }
+	if(fread(buf, len, 1, f) != 1) {
+		logger(mesh, MESHLINK_ERROR, "Cannot read config file: %s\n", strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
+
+	if(key) {
+		uint8_t *decrypted = xmalloc(len);
+		size_t decrypted_len = len;
+		chacha_poly1305_ctx_t *ctx = chacha_poly1305_init();
+		chacha_poly1305_set_key(ctx, key);
+
+		if(len > 12 && chacha_poly1305_decrypt_iv96(ctx, buf, buf + 12, len - 12, decrypted, &decrypted_len)) {
+			chacha_poly1305_exit(ctx);
+			free(buf);
+			config->buf = decrypted;
+			config->len = decrypted_len;
+			return true;
+		} else {
+			logger(mesh, MESHLINK_ERROR, "Cannot decrypt config file\n");
+			meshlink_errno = MESHLINK_ESTORAGE;
+			chacha_poly1305_exit(ctx);
+			free(decrypted);
+			free(buf);
+			return false;
+		}
+	}
 
-  syslog(LOG_ERR, _("Hostname or IP address expected for configuration variable %s in %s line %d"),
-         cfg->variable, cfg->file, cfg->line);
-  return 0;
+	config->buf = buf;
+	config->len = len;
+
+	return true;
 }
 
-int get_config_port(config_t *cfg, port_t *result)
-{
-cp
-  if(!cfg)
-    return 0;
-
-  if(sscanf(cfg->value, "%hu", result) == 1)
-    {
-      *result = htons(*result);
-      return 1;
-    }
-
-  syslog(LOG_ERR, _("Port number expected for configuration variable %s in %s line %d"),
-         cfg->variable, cfg->file, cfg->line);
-  return 0;
+/// Write a configuration file to a FILE handle.
+bool config_write_file(meshlink_handle_t *mesh, FILE *f, const config_t *config, const void *key) {
+	assert(f);
+
+	if(key) {
+		uint8_t buf[config->len + 16];
+		size_t len = sizeof(buf);
+		uint8_t seqbuf[12];
+		randomize(&seqbuf, sizeof(seqbuf));
+		chacha_poly1305_ctx_t *ctx = chacha_poly1305_init();
+		chacha_poly1305_set_key(ctx, key);
+		bool success = false;
+
+		if(chacha_poly1305_encrypt_iv96(ctx, seqbuf, config->buf, config->len, buf, &len)) {
+			success = fwrite(seqbuf, sizeof(seqbuf), 1, f) == 1 && fwrite(buf, len, 1, f) == 1;
+		} else {
+			logger(mesh, MESHLINK_ERROR, "Cannot encrypt config file\n");
+			meshlink_errno = MESHLINK_ESTORAGE;
+		}
+
+		chacha_poly1305_exit(ctx);
+		return success;
+	}
+
+	if(fwrite(config->buf, config->len, 1, f) != 1) {
+		logger(mesh, MESHLINK_ERROR, "Cannot write config file: %s", strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
+
+	if(fsync(fileno(f))) {
+		logger(mesh, MESHLINK_ERROR, "Failed to sync file: %s\n", strerror(errno));
+		return false;
+	}
+
+	return true;
+}
+
+/// Free resources of a loaded configuration file.
+void config_free(config_t *config) {
+	assert(!config->len || config->buf);
+
+	free((uint8_t *)config->buf);
+	config->buf = NULL;
+	config->len = 0;
+}
+
+/// Check the presence of a host configuration file.
+bool config_exists(meshlink_handle_t *mesh, const char *conf_subdir, const char *name) {
+	assert(conf_subdir);
+
+	if(!mesh->confbase) {
+		return false;
+	}
+
+	char path[PATH_MAX];
+	make_host_path(mesh, conf_subdir, name, path, sizeof(path));
+
+	return access(path, F_OK) == 0;
 }
 
-int get_config_subnet(config_t *cfg, subnet_t **result)
-{
-  subnet_t *subnet;
-cp
-  if(!cfg)
-    return 0;
+/// Read a host configuration file.
+bool config_read(meshlink_handle_t *mesh, const char *conf_subdir, const char *name, config_t *config, void *key) {
+	assert(conf_subdir);
+
+	if(!mesh->confbase) {
+		return false;
+	}
 
-  subnet = str2net(cfg->value);
+	char path[PATH_MAX];
+	make_host_path(mesh, conf_subdir, name, path, sizeof(path));
 
-  if(!subnet)
-    {
-      syslog(LOG_ERR, _("Subnet expected for configuration variable %s in %s line %d"),
-             cfg->variable, cfg->file, cfg->line);
-      return 0;
-    }
+	FILE *f = fopen(path, "r");
 
-  /* Teach newbies what subnets are... */
+	if(!f) {
+		logger(mesh, MESHLINK_ERROR, "Failed to open `%s': %s", path, strerror(errno));
+		return false;
+	}
 
-  if(((subnet->type == SUBNET_IPV4) && maskcheck(&subnet->net.ipv4.address, subnet->net.ipv4.prefixlength, sizeof(ipv4_t)))
-     || ((subnet->type == SUBNET_IPV6) && maskcheck(&subnet->net.ipv6.address, subnet->net.ipv6.prefixlength, sizeof(ipv6_t))))
-    {
-      syslog(LOG_ERR, _("Network address and prefix length do not match for configuration variable %s in %s line %d"),
-             cfg->variable, cfg->file, cfg->line);
-      free(subnet);
-      return 0;
-    }
+	if(!config_read_file(mesh, f, config, key)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to read `%s': %s", path, strerror(errno));
+		fclose(f);
+		return false;
+	}
 
-  *result = subnet;
+	fclose(f);
 
-  return 1;
+	return true;
 }
 
-/*
-  Read exactly one line and strip the trailing newline if any.  If the
-  file was on EOF, return NULL. Otherwise, return all the data in a
-  dynamically allocated buffer.
-
-  If line is non-NULL, it will be used as an initial buffer, to avoid
-  unnecessary mallocing each time this function is called.  If buf is
-  given, and buf needs to be expanded, the var pointed to by buflen
-  will be increased.
-*/
-char *readline(FILE *fp, char **buf, size_t *buflen)
-{
-  char *newline = NULL;
-  char *p;
-  char *line; /* The array that contains everything that has been read
-                 so far */
-  char *idx; /* Read into this pointer, which points to an offset
-                within line */
-  size_t size, newsize; /* The size of the current array pointed to by
-                           line */
-  size_t maxlen; /* Maximum number of characters that may be read with
-                    fgets.  This is newsize - oldsize. */
-
-  if(feof(fp))
-    return NULL;
-
-  if((buf != NULL) && (buflen != NULL))
-    {
-      size = *buflen;
-      line = *buf;
-    }
-  else
-    {
-      size = 100;
-      line = xmalloc(size);
-    }
-
-  maxlen = size;
-  idx = line;
-  *idx = 0;
-  for(;;)
-    {
-      errno = 0;
-      p = fgets(idx, maxlen, fp);
-      if(p == NULL)  /* EOF or error */
-	{
-	  if(feof(fp))
-	    break;
-
-	  /* otherwise: error; let the calling function print an error
-             message if applicable */
-	  free(line);
-	  return NULL;
-	}
-
-      newline = strchr(p, '\n');
-      if(newline == NULL)
-	/* We haven't yet read everything to the end of the line */
-	{
-	  newsize = size << 1;
-	  line = xrealloc(line, newsize);
-	  idx = &line[size - 1];
-	  maxlen = newsize - size + 1;
-	  size = newsize;
-	}
-      else
-	{
-	  *newline = '\0'; /* kill newline */
-	  break;  /* yay */
-	}
-    }
-
-  if((buf != NULL) && (buflen != NULL))
-    {
-      *buflen = size;
-      *buf = line;
-    }
-  return line;
+bool config_scan_all(meshlink_handle_t *mesh, const char *conf_subdir, const char *conf_type, config_scan_action_t action, void *arg) {
+	assert(conf_subdir);
+	assert(conf_type);
+
+	if(!mesh->confbase) {
+		return true;
+	}
+
+	DIR *dir;
+	struct dirent *ent;
+	char dname[PATH_MAX];
+	snprintf(dname, sizeof(dname), "%s" SLASH "%s" SLASH "%s", mesh->confbase, conf_subdir, conf_type);
+
+	dir = opendir(dname);
+
+	if(!dir) {
+		logger(mesh, MESHLINK_ERROR, "Could not open %s: %s", dname, strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
+
+	while((ent = readdir(dir))) {
+		if(ent->d_name[0] == '.') {
+			continue;
+		}
+
+		if(!action(mesh, ent->d_name, arg)) {
+			closedir(dir);
+			return false;
+		}
+	}
+
+	closedir(dir);
+	return true;
 }
 
-/*
-  Parse a configuration file and put the results in the configuration tree
-  starting at *base.
-*/
-int read_config_file(avl_tree_t *config_tree, const char *fname)
-{
-  int err = -2; /* Parse error */
-  FILE *fp;
-  char *buffer, *line;
-  char *variable, *value;
-  int lineno = 0, ignore = 0;
-  config_t *cfg;
-  size_t bufsize;
-
-cp
-  if((fp = fopen (fname, "r")) == NULL)
-    {
-      syslog(LOG_ERR, _("Cannot open config file %s: %s"), fname, strerror(errno));
-      return -3;
-    }
-
-  bufsize = 100;
-  buffer = xmalloc(bufsize);
-
-  for(;;)
-    {
-      if((line = readline(fp, &buffer, &bufsize)) == NULL)
-	{
-	  err = -1;
-	  break;
-	}
-
-      if(feof(fp))
-	{
-	  err = 0;
-	  break;
-	}
-
-      lineno++;
-
-      if((variable = strtok(line, "\t =")) == NULL)
-	continue; /* no tokens on this line */
-
-      if(variable[0] == '#')
-	continue; /* comment: ignore */
-
-      if(!strcmp(variable, "-----BEGIN"))
-        ignore = 1;
-
-      if(!ignore)
-        {
-          if(((value = strtok(NULL, "\t\n\r =")) == NULL) || value[0] == '#')
-	    {
-	      syslog(LOG_ERR, _("No value for variable `%s' on line %d while reading config file %s"),
-		      variable, lineno, fname);
-	      break;
-	    }
-
-          cfg = new_config();
-          cfg->variable = xstrdup(variable);
-          cfg->value = xstrdup(value);
-          cfg->file = xstrdup(fname);
-          cfg->line = lineno;
-
-          config_add(config_tree, cfg);
-       }
-
-      if(!strcmp(variable, "-----END"))
-        ignore = 0;
-    }
-
-  free(buffer);
-  fclose (fp);
-cp
-  return err;
+/// Write a host configuration file.
+bool config_write(meshlink_handle_t *mesh, const char *conf_subdir, const char *name, const config_t *config, void *key) {
+	assert(conf_subdir);
+	assert(name);
+	assert(config);
+
+	if(!mesh->confbase) {
+		return true;
+	}
+
+	char path[PATH_MAX];
+	char tmp_path[PATH_MAX + 4];
+	make_host_path(mesh, conf_subdir, name, path, sizeof(path));
+	snprintf(tmp_path, sizeof(tmp_path), "%s.tmp", path);
+
+	FILE *f = fopen(tmp_path, "w");
+
+	if(!f) {
+		logger(mesh, MESHLINK_ERROR, "Failed to open `%s': %s", tmp_path, strerror(errno));
+		return false;
+	}
+
+	if(!config_write_file(mesh, f, config, key)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to write `%s': %s", tmp_path, strerror(errno));
+		fclose(f);
+		return false;
+	}
+
+	if(fsync(fileno(f))) {
+		logger(mesh, MESHLINK_ERROR, "Failed to sync `%s': %s", tmp_path, strerror(errno));
+		fclose(f);
+		return false;
+	}
+
+	if(fclose(f)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to close `%s': %s", tmp_path, strerror(errno));
+		return false;
+	}
+
+	if(rename(tmp_path, path)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to rename `%s' to `%s': %s", tmp_path, path, strerror(errno));
+		return false;
+	}
+
+	return true;
 }
 
-int read_server_config()
-{
-  char *fname;
-  int x;
-cp
-  asprintf(&fname, "%s/tinc.conf", confbase);
-  x = read_config_file(config_tree, fname);
-  if(x == -1) /* System error: complain */
-    {
-      syslog(LOG_ERR, _("Failed to read `%s': %s"), fname, strerror(errno));
-    }
-  free(fname);
-cp
-  return x;
+/// Read the main configuration file.
+bool main_config_read(meshlink_handle_t *mesh, const char *conf_subdir, config_t *config, void *key) {
+	assert(conf_subdir);
+	assert(config);
+
+	if(!mesh->confbase) {
+		return false;
+	}
+
+	char path[PATH_MAX];
+	make_main_path(mesh, conf_subdir, path, sizeof(path));
+
+	FILE *f = fopen(path, "r");
+
+	if(!f) {
+		logger(mesh, MESHLINK_ERROR, "Failed to open `%s': %s", path, strerror(errno));
+		return false;
+	}
+
+	if(!config_read_file(mesh, f, config, key)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to read `%s': %s", path, strerror(errno));
+		fclose(f);
+		return false;
+	}
+
+	fclose(f);
+
+	return true;
 }
 
-int isadir(const char* f)
-{
-  struct stat s;
+/// Write the main configuration file.
+bool main_config_write(meshlink_handle_t *mesh, const char *conf_subdir, const config_t *config, void *key) {
+	assert(conf_subdir);
+	assert(config);
 
-  if(stat(f, &s) < 0)
-    return 0;
-  else
-    return S_ISDIR(s.st_mode);
+	if(!mesh->confbase) {
+		return true;
+	}
+
+	char path[PATH_MAX];
+	char tmp_path[PATH_MAX + 4];
+	make_main_path(mesh, conf_subdir, path, sizeof(path));
+	snprintf(tmp_path, sizeof(tmp_path), "%s.tmp", path);
+
+	FILE *f = fopen(tmp_path, "w");
+
+	if(!f) {
+		logger(mesh, MESHLINK_ERROR, "Failed to open `%s': %s", tmp_path, strerror(errno));
+		return false;
+	}
+
+	if(!config_write_file(mesh, f, config, key)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to write `%s': %s", tmp_path, strerror(errno));
+		fclose(f);
+		return false;
+	}
+
+	if(fsync(fileno(f))) {
+		logger(mesh, MESHLINK_ERROR, "Failed to sync `%s': %s", tmp_path, strerror(errno));
+		fclose(f);
+		return false;
+	}
+
+	if(rename(tmp_path, path)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to rename `%s' to `%s': %s", tmp_path, path, strerror(errno));
+		fclose(f);
+		return false;
+	}
+
+	if(fclose(f)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to close `%s': %s", tmp_path, strerror(errno));
+		return false;
+	}
+
+	return true;
+}
+
+/// Read an invitation file from the confbase sub-directory, and immediately delete it.
+bool invitation_read(meshlink_handle_t *mesh, const char *conf_subdir, const char *name, config_t *config, void *key) {
+	assert(conf_subdir);
+	assert(name);
+	assert(config);
+
+	if(!mesh->confbase) {
+		return false;
+	}
+
+	char path[PATH_MAX];
+	char used_path[PATH_MAX];
+	make_invitation_path(mesh, conf_subdir, name, path, sizeof(path));
+	make_used_invitation_path(mesh, conf_subdir, name, used_path, sizeof(used_path));
+
+	// Atomically rename the invitation file
+	if(rename(path, used_path)) {
+		if(errno == ENOENT) {
+			logger(mesh, MESHLINK_ERROR, "Peer tried to use non-existing invitation %s\n", name);
+		} else {
+			logger(mesh, MESHLINK_ERROR, "Error trying to rename invitation %s\n", name);
+		}
+
+		return false;
+	}
+
+	FILE *f = fopen(used_path, "r");
+
+	if(!f) {
+		logger(mesh, MESHLINK_ERROR, "Failed to open `%s': %s", path, strerror(errno));
+		return false;
+	}
+
+	// Check the timestamp
+	struct stat st;
+
+	if(fstat(fileno(f), &st)) {
+		logger(mesh, MESHLINK_ERROR, "Could not stat invitation file %s\n", name);
+		fclose(f);
+		unlink(used_path);
+		return false;
+	}
+
+	if(mesh->loop.now.tv_sec > st.st_mtime + mesh->invitation_timeout) {
+		logger(mesh, MESHLINK_ERROR, "Peer tried to use an outdated invitation file %s\n", name);
+		fclose(f);
+		unlink(used_path);
+		return false;
+	}
+
+	if(!config_read_file(mesh, f, config, key)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to read `%s': %s", path, strerror(errno));
+		fclose(f);
+		unlink(used_path);
+		return false;
+	}
+
+	fclose(f);
+
+	unlink(used_path);
+	return true;
 }
 
-int is_safe_path(const char *file)
-{
-  char *p;
-  const char *f;
-  char x;
-  struct stat s;
-  char l[MAXBUFSIZE];
-
-  if(*file != '/')
-    {
-      syslog(LOG_ERR, _("`%s' is not an absolute path"), file);
-      return 0;
-    }
-
-  p = strrchr(file, '/');
-
-  if(p == file)		/* It's in the root */
-    p++;
-
-  x = *p;
-  *p = '\0';
-
-  f = file;
-check1:
-  if(lstat(f, &s) < 0)
-    {
-      syslog(LOG_ERR, _("Couldn't stat `%s': %s"), f, strerror(errno));
-      return 0;
-    }
-
-  if(s.st_uid != geteuid())
-    {
-      syslog(LOG_ERR, _("`%s' is owned by UID %d instead of %d"),
-	      f, s.st_uid, geteuid());
-      return 0;
-    }
-
-  if(S_ISLNK(s.st_mode))
-    {
-      syslog(LOG_WARNING, _("Warning: `%s' is a symlink"),
-	      f);
-
-      if(readlink(f, l, MAXBUFSIZE) < 0)
-        {
-          syslog(LOG_ERR, _("Unable to read symbolic link `%s': %s"), f, strerror(errno));
-          return 0;
-        }
-
-      f = l;
-      goto check1;
-    }
-
-  *p = x;
-  f = file;
-
-check2:
-  if(lstat(f, &s) < 0 && errno != ENOENT)
-    {
-      syslog(LOG_ERR, _("Couldn't stat `%s': %s"), f, strerror(errno));
-      return 0;
-    }
-
-  if(errno == ENOENT)
-    return 1;
-
-  if(s.st_uid != geteuid())
-    {
-      syslog(LOG_ERR, _("`%s' is owned by UID %d instead of %d"),
-	      f, s.st_uid, geteuid());
-      return 0;
-    }
-
-  if(S_ISLNK(s.st_mode))
-    {
-      syslog(LOG_WARNING, _("Warning: `%s' is a symlink"),
-	      f);
-
-      if(readlink(f, l, MAXBUFSIZE) < 0)
-        {
-          syslog(LOG_ERR, _("Unable to read symbolic link `%s': %s"), f, strerror(errno));
-          return 0;
-        }
-
-      f = l;
-      goto check2;
-    }
-
-  if(s.st_mode & 0007)
-    {
-      /* Accessible by others */
-      syslog(LOG_ERR, _("`%s' has unsecure permissions"),
-	      f);
-      return 0;
-    }
-
-  return 1;
+/// Write an invitation file.
+bool invitation_write(meshlink_handle_t *mesh, const char *conf_subdir, const char *name, const config_t *config, void *key) {
+	assert(conf_subdir);
+	assert(name);
+	assert(config);
+
+	if(!mesh->confbase) {
+		return false;
+	}
+
+	char path[PATH_MAX];
+	make_invitation_path(mesh, conf_subdir, name, path, sizeof(path));
+
+	FILE *f = fopen(path, "w");
+
+	if(!f) {
+		logger(mesh, MESHLINK_ERROR, "Failed to open `%s': %s", path, strerror(errno));
+		return false;
+	}
+
+	if(!config_write_file(mesh, f, config, key)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to write `%s': %s", path, strerror(errno));
+		fclose(f);
+		return false;
+	}
+
+	if(fsync(fileno(f))) {
+		logger(mesh, MESHLINK_ERROR, "Failed to sync `%s': %s", path, strerror(errno));
+		fclose(f);
+		return false;
+	}
+
+	if(fclose(f)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to close `%s': %s", path, strerror(errno));
+		return false;
+	}
+
+	return true;
 }
 
-FILE *ask_and_safe_open(const char* filename, const char* what, const char* mode)
-{
-  FILE *r;
-  char *directory;
-  char *fn;
-
-  /* Check stdin and stdout */
-  if(!isatty(0) || !isatty(1))
-    {
-      /* Argh, they are running us from a script or something.  Write
-         the files to the current directory and let them burn in hell
-         for ever. */
-      fn = xstrdup(filename);
-    }
-  else
-    {
-      /* Ask for a file and/or directory name. */
-      fprintf(stdout, _("Please enter a file to save %s to [%s]: "),
-	      what, filename);
-      fflush(stdout);
-
-      if((fn = readline(stdin, NULL, NULL)) == NULL)
-	{
-	  fprintf(stderr, _("Error while reading stdin: %s\n"), strerror(errno));
-	  return NULL;
-	}
-
-      if(strlen(fn) == 0)
-	/* User just pressed enter. */
-	fn = xstrdup(filename);
-    }
-
-  if((strchr(fn, '/') == NULL) || (fn[0] != '/'))
-    {
-      /* The directory is a relative path or a filename. */
-      char *p;
-
-      directory = get_current_dir_name();
-      asprintf(&p, "%s/%s", directory, fn);
-      free(fn);
-      free(directory);
-      fn = p;
-    }
-
-  umask(0077); /* Disallow everything for group and other */
-
-  /* Open it first to keep the inode busy */
-  if((r = fopen(fn, mode)) == NULL)
-    {
-      fprintf(stderr, _("Error opening file `%s': %s\n"),
-	      fn, strerror(errno));
-      free(fn);
-      return NULL;
-    }
-
-  /* Then check the file for nasty attacks */
-  if(!is_safe_path(fn))  /* Do not permit any directories that are
-                            readable or writeable by other users. */
-    {
-      fprintf(stderr, _("The file `%s' (or any of the leading directories) has unsafe permissions.\n"
-			"I will not create or overwrite this file.\n"),
-			fn);
-      fclose(r);
-      free(fn);
-      return NULL;
-    }
-
-  free(fn);
-
-  return r;
+/// Purge old invitation files
+size_t invitation_purge_old(meshlink_handle_t *mesh, time_t deadline) {
+	if(!mesh->confbase) {
+		return true;
+	}
+
+	char path[PATH_MAX];
+	make_invitation_path(mesh, "current", "", path, sizeof(path));
+
+	DIR *dir = opendir(path);
+
+	if(!dir) {
+		logger(mesh, MESHLINK_DEBUG, "Could not read directory %s: %s\n", path, strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return 0;
+	}
+
+	errno = 0;
+	size_t count = 0;
+	struct dirent *ent;
+
+	while((ent = readdir(dir))) {
+		if(strlen(ent->d_name) != 24) {
+			continue;
+		}
+
+		char invname[PATH_MAX];
+		struct stat st;
+
+		if(snprintf(invname, sizeof(invname), "%s" SLASH "%s", path, ent->d_name) >= PATH_MAX) {
+			logger(mesh, MESHLINK_DEBUG, "Filename too long: %s" SLASH "%s", path, ent->d_name);
+			continue;
+		}
+
+		if(!stat(invname, &st)) {
+			if(mesh->invitation_key && deadline < st.st_mtime) {
+				count++;
+			} else {
+				unlink(invname);
+			}
+		} else {
+			logger(mesh, MESHLINK_DEBUG, "Could not stat %s: %s\n", invname, strerror(errno));
+			errno = 0;
+		}
+	}
+
+	if(errno) {
+		logger(mesh, MESHLINK_DEBUG, "Error while reading directory %s: %s\n", path, strerror(errno));
+		closedir(dir);
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return 0;
+	}
+
+	closedir(dir);
+
+	return count;
 }