X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=src%2Fconf.c;h=9527c1edf5c13cda07db36b6255ec4ee777b078e;hb=be83b0af60449c7b35d17d97f2e6dc12f611e831;hp=a3c5f693f8052f7b1712ff0c7bccedf62c8154cb;hpb=ab33c1aa6081f07333bf1de00e4036dd2b4628a6;p=meshlink

diff --git a/src/conf.c b/src/conf.c
index a3c5f693..9527c1ed 100644
--- a/src/conf.c
+++ b/src/conf.c
@@ -1,9 +1,6 @@
 /*
-    conf.c -- configuration code
-    Copyright (C) 1998 Robert van der Meulen
-    Copyright (C) 1998,1999,2000 Ivo Timmermans <itimmermans@bigfoot.com>
-                            2000 Guus Sliepen <guus@sliepen.warande.net>
-			    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
@@ -15,484 +12,1027 @@
     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 1.9.4.30 2000/12/01 12:36:36 zarq 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 "system.h"
 #include <assert.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 <sys/types.h>
-#include <unistd.h>
-
-#include <xalloc.h>
-#include <utils.h> /* for cp */
+#include <utime.h>
 
 #include "conf.h"
-#include "netutl.h" /* for strtoip */
+#include "crypto.h"
+#include "logger.h"
+#include "meshlink_internal.h"
+#include "xalloc.h"
+#include "packmsg.h"
 
-#include "system.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);
 
-config_t *config = NULL;
-int debug_lvl = 0;
-int timeout = 0; /* seconds before timeout */
-char *confbase = NULL;           /* directory in which all config files are */
-char *netname = NULL;            /* name of the vpn network */
+	snprintf(path, len, "%s" SLASH "%s" SLASH "meshlink.conf", mesh->confbase, conf_subdir);
+}
 
-/* Will be set if HUP signal is received. It will be processed when it is safe. */
-int sighup = 0;
+/// 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);
 
-/*
-  These are all the possible configurable values
-*/
-static internal_config_t hazahaza[] = {
-/* Main configuration file keywords */
-  { "Name",         config_name,       TYPE_NAME },
-  { "ConnectTo",    config_connectto,      TYPE_NAME },
-  { "PingTimeout",  config_pingtimeout,    TYPE_INT },
-  { "TapDevice",    config_tapdevice,      TYPE_NAME },
-  { "PrivateKey",   config_privatekey,     TYPE_NAME },
-  { "KeyExpire",    config_keyexpire,      TYPE_INT },
-  { "Hostnames",    config_hostnames,    TYPE_BOOL },
-  { "Interface",    config_interface,      TYPE_NAME },
-  { "InterfaceIP",  config_interfaceip,    TYPE_IP },
-/* Host configuration file keywords */
-  { "Address",      config_address,        TYPE_NAME },
-  { "Port",         config_port,           TYPE_INT },
-  { "PublicKey",    config_publickey,      TYPE_NAME },
-  { "Subnet",       config_subnet,         TYPE_IP },		/* Use IPv4 subnets only for now */
-  { "RestrictHosts", config_restricthosts, TYPE_BOOL },
-  { "RestrictSubnets", config_restrictsubnets, TYPE_BOOL },
-  { "RestrictAddress", config_restrictaddress, TYPE_BOOL },
-  { "RestrictPort", config_restrictport,   TYPE_BOOL },
-  { "IndirectData", config_indirectdata,   TYPE_BOOL },
-  { "TCPonly",      config_tcponly,        TYPE_BOOL },
-  { NULL, 0, 0 }
-};
+	snprintf(path, len, "%s" SLASH "%s" SLASH "hosts" SLASH "%s", mesh->confbase, conf_subdir, name);
+}
 
-/*
-  Add given value to the list of configs cfg
-*/
-config_t *
-add_config_val(config_t **cfg, int argtype, char *val)
-{
-  config_t *p;
-  char *q;
-cp
-  p = (config_t*)xmalloc(sizeof(*p));
-  p->data.val = 0;
-
-  switch(argtype)
-    {
-    case TYPE_INT:
-      p->data.val = strtol(val, &q, 0);
-      if(q && *q)
-	p->data.val = 0;
-      break;
-    case TYPE_NAME:
-      p->data.ptr = xmalloc(strlen(val) + 1);
-      strcpy(p->data.ptr, val);
-      break;
-    case TYPE_IP:
-      p->data.ip = strtoip(val);
-      break;
-    case TYPE_BOOL:
-      if(!strcasecmp("yes", val))
-	p->data.val = stupid_true;
-      else if(!strcasecmp("no", val))
-	p->data.val = stupid_false;
-      else
-	p->data.val = 0;
-    }
-
-  p->argtype = argtype;
-
-  if(p->data.val)
-    {
-      p->next = *cfg;
-      *cfg = p;
-cp
-      return p;
-    }
-  else
-    {
-      free(p);
-cp
-      return NULL;
-    }
+/// 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);
 }
 
-/*
-  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))
-    *buf = size;
-  return line;
+/// 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);
 }
 
-/*
-  Parse a configuration file and put the results in the configuration tree
-  starting at *base.
-*/
-int read_config_file(config_t **base, const char *fname)
-{
-  int err = -1;
-  FILE *fp;
-  char *line;
-  char *p, *q;
-  int i, lineno = 0;
-  config_t *cfg;
-  size_t bufsize;
-  
-cp
-  if((fp = fopen (fname, "r")) == NULL)
-    return -1;
-
-  bufsize = 100;
-  line = xmalloc(bufsize);
-  
-  for(;;)
-    {
-      if((line = readline(fp, line, &bufsize)) == NULL)
-	{
-	  err = -1;
-	  break;
-	}
-
-      if(feof(fp))
-	{
-	  err = 0;
-	  break;
-	}
-
-      lineno++;
-
-      if((p = strtok(line, "\t =")) == NULL)
-	continue; /* no tokens on this line */
-
-      if(p[0] == '#')
-	continue; /* comment: ignore */
-
-      for(i = 0; hazahaza[i].name != NULL; i++)
-	if(!strcasecmp(hazahaza[i].name, p))
-	  break;
-
-      if(!hazahaza[i].name)
-	{
-	  syslog(LOG_ERR, _("Invalid variable name `%s' on line %d while reading config file %s"),
-		  p, lineno, fname);
-          break;
-	}
-
-      if(((q = strtok(NULL, "\t\n\r =")) == NULL) || q[0] == '#')
-	{
-	  fprintf(stderr, _("No value for variable `%s' on line %d while reading config file %s"),
-		  hazahaza[i].name, lineno, fname);
-	  break;
-	}
-
-      cfg = add_config_val(base, hazahaza[i].argtype, q);
-      if(cfg == NULL)
-	{
-	  fprintf(stderr, _("Invalid value for variable `%s' on line %d while reading config file %s"),
-		  hazahaza[i].name, lineno, fname);
-	  break;
-	}
-
-      cfg->which = hazahaza[i].which;
-      if(!config)
-	config = cfg;
-    }
-
-  free(line);
-  fclose (fp);
-cp
-  return err;
+/// Remove a directory recursively
+static bool deltree(const char *dirname) {
+	assert(dirname);
+
+	DIR *d = opendir(dirname);
+
+	if(d) {
+		struct dirent *ent;
+
+		while((ent = readdir(d))) {
+			if(ent->d_name[0] == '.') {
+				continue;
+			}
+
+			char filename[PATH_MAX];
+			snprintf(filename, sizeof(filename), "%s" SLASH "%s", dirname, ent->d_name);
+
+			if(unlink(filename)) {
+				if(!deltree(filename)) {
+					return false;
+				}
+			}
+		}
+
+		closedir(d);
+	} else {
+		return errno == ENOENT;
+	}
+
+	return rmdir(dirname) == 0;
 }
 
-int read_server_config()
-{
-  char *fname;
-  int x;
-cp
-  asprintf(&fname, "%s/tinc.conf", confbase);
-  x = read_config_file(&config, fname);
-  if(x != 0)
-    {
-      fprintf(stderr, _("Failed to read `%s': %m\n"),
-	      fname);
-    }
-  free(fname);
-cp
-  return x;  
+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;
 }
 
-/*
-  Look up the value of the config option type
-*/
-const config_t *get_config_val(config_t *p, which_t type)
-{
-cp
-  for(; p != NULL; p = p->next)
-    if(p->which == type)
-      break;
-cp
-  return p;
+/// 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;
 }
 
-/*
-  Remove the complete configuration tree.
-*/
-void clear_config(config_t **base)
-{
-  config_t *p, *next;
-cp
-  for(p = *base; p != NULL; p = next)
-    {
-      next = p->next;
-      if(p->data.ptr && (p->argtype == TYPE_NAME))
-        {
-          free(p->data.ptr);
-        }
-      free(p);
-    }
-  *base = NULL;
-cp
+/// Create a fresh configuration directory
+bool config_init(meshlink_handle_t *mesh, const char *conf_subdir) {
+	assert(conf_subdir);
+
+	if(!mesh->confbase) {
+		return true;
+	}
+
+	char path[PATH_MAX];
+
+	// Create "current" sub-directory in the confbase
+	snprintf(path, sizeof(path), "%s" SLASH "%s", mesh->confbase, conf_subdir);
+
+	if(!deltree(path)) {
+		logger(mesh, MESHLINK_DEBUG, "Could not delete directory %s: %s\n", path, strerror(errno));
+		return false;
+	}
+
+	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;
 }
 
-int isadir(const char* f)
-{
-  struct stat s;
+/// Wipe an existing configuration directory
+bool config_destroy(const char *confbase, const char *conf_subdir) {
+	assert(conf_subdir);
 
-  if(stat(f, &s) < 0)
-    {
-      fprintf(stderr, _("Couldn't stat `%s': %m\n"),
-	      f);
-      return -1;
-    }
+	if(!confbase) {
+		return true;
+	}
+
+	struct stat st;
+
+	char path[PATH_MAX];
 
-  return S_ISDIR(s.st_mode);
+	// 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);
+
+	if(!deltree(path)) {
+		logger(NULL, MESHLINK_ERROR, "Cannot delete %s: %s\n", path, strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
+
+	return sync_path(confbase);
 }
 
-int is_safe_path(const char *file)
-{
-  char *p;
-  struct stat s;
-
-  p = strrchr(file, '/');
-  assert(p); /* p has to contain a / */
-  *p = '\0';
-  if(stat(file, &s) < 0)
-    {
-      fprintf(stderr, _("Couldn't stat `%s': %m\n"),
-	      file);
-      return 0;
-    }
-  if(s.st_uid != geteuid())
-    {
-      fprintf(stderr, _("`%s' is owned by UID %d instead of %d.\n"),
-	      file, s.st_uid, geteuid());
-      return 0;
-    }
-  if(S_ISLNK(s.st_mode))
-    {
-      fprintf(stderr, _("Warning: `%s' is a symlink\n"),
-	      file);
-      /* fixme: read the symlink and start again */
-    }
-
-  *p = '/';
-  if(stat(file, &s) < 0 && errno != ENOENT)
-    {
-      fprintf(stderr, _("Couldn't stat `%s': %m\n"),
-	      file);
-      return 0;
-    }
-  if(errno == ENOENT)
-    return 1;
-  if(s.st_uid != geteuid())
-    {
-      fprintf(stderr, _("`%s' is owned by UID %d instead of %d.\n"),
-	      file, s.st_uid, geteuid());
-      return 0;
-    }
-  if(S_ISLNK(s.st_mode))
-    {
-      fprintf(stderr, _("Warning: `%s' is a symlink\n"),
-	      file);
-      /* fixme: read the symlink and start again */
-    }
-  if(s.st_mode & 0007)
-    {
-      /* Accessible by others */
-      fprintf(stderr, _("`%s' has unsecure permissions.\n"),
-	      file);
-      return 0;
-    }
-  
-  return 1;
+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);
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
+
+	// Delete if already exists and create a new destination directory
+	if(!deltree(dst_dir_name)) {
+		logger(NULL, MESHLINK_ERROR, "Cannot delete %s: %s\n", dst_dir_name, strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
+
+	if(mkdir(dst_dir_name, 0700)) {
+		logger(NULL, MESHLINK_ERROR, "Could not create directory %s\n", dst_filename);
+		meshlink_errno = MESHLINK_ESTORAGE;
+		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);
+				meshlink_errno = MESHLINK_ESTORAGE;
+				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));
+				meshlink_errno = MESHLINK_ESTORAGE;
+				return false;
+			}
+
+			FILE *f = fopen(src_filename, "r");
+
+			if(!f) {
+				logger(NULL, MESHLINK_ERROR, "Failed to open `%s': %s\n", src_filename, strerror(errno));
+				meshlink_errno = MESHLINK_ESTORAGE;
+				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);
+				meshlink_errno = MESHLINK_ESTORAGE;
+				return false;
+			}
+
+			if(fclose(f)) {
+				logger(NULL, MESHLINK_ERROR, "Failed to close `%s': %s\n", src_filename, strerror(errno));
+				config_free(&config);
+				meshlink_errno = MESHLINK_ESTORAGE;
+				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);
+				meshlink_errno = MESHLINK_ESTORAGE;
+				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);
+				meshlink_errno = MESHLINK_ESTORAGE;
+				return false;
+			}
+
+			if(fclose(f)) {
+				logger(NULL, MESHLINK_ERROR, "Failed to close `%s': %s", dst_filename, strerror(errno));
+				config_free(&config);
+				meshlink_errno = MESHLINK_ESTORAGE;
+				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));
+				meshlink_errno = MESHLINK_ESTORAGE;
+				return false;
+			}
+		}
+	}
+
+	closedir(src_dir);
+	return true;
+}
+
+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);
+
+	char src_filename[PATH_MAX];
+	char dst_filename[PATH_MAX];
+
+	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);
+}
+
+/// Check the presence of the main configuration file.
+bool main_config_exists(meshlink_handle_t *mesh, const char *conf_subdir) {
+	assert(conf_subdir);
+
+	if(!mesh->confbase) {
+		return false;
+	}
+
+	char path[PATH_MAX];
+	make_main_path(mesh, conf_subdir, path, sizeof(path));
+	return access(path, F_OK) == 0;
+}
+
+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 && sync_path(mesh->confbase);
+}
+
+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;
 }
 
-FILE *ask_and_safe_open(const char* filename, const char* what)
-{
-  FILE *r;
-  char *directory;
-  char *fn;
-  int len;
-
-  /* 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);  /* Don't wait for a newline */
-      if((fn = readline(stdin, NULL, NULL)) == NULL)
-	{
-	  fprintf(stderr, _("Error while reading stdin: %m\n"));
-	  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();
-      len = strlen(fn) + strlen(directory) + 2; /* 1 for the / */
-      p = xmalloc(len);
-      snprintf(p, len, "%s/%s", directory, fn);
-      free(fn);
-      free(directory);
-      fn = p;
-    }
-
-  if(isadir(fn) > 0) /* -1 is error */
-    {
-      char *p;
-
-      len = strlen(fn) + strlen(filename) + 2; /* 1 for the / */
-      p = xmalloc(len);
-      snprintf(p, len, "%s/%s", fn, filename);
-      free(fn);
-      fn = p;
-    }
-
-  umask(0077); /* Disallow everything for group and other */
-  
-  /* Open it first to keep the inode busy */
-  if((r = fopen(fn, "w")) == NULL)
-    {
-      fprintf(stderr, _("Error opening file `%s': %m\n"),
-	      fn);
-      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;
+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(main_config_decrypt(mesh, "new")) {
+			if(!config_destroy(mesh->confbase, "current")) {
+				return false;
+			}
+
+			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) {
+		if(!config_destroy(mesh->confbase, "old") || !config_destroy(mesh->confbase, "new")) {
+			return false;
+		}
+	}
+
+	return confbase_exists;
+}
+
+/// Lock the main configuration file. Creates confbase if necessary.
+bool main_config_lock(meshlink_handle_t *mesh) {
+	if(!mesh->confbase) {
+		return true;
+	}
+
+	if(mkdir(mesh->confbase, 0700) && errno != EEXIST) {
+		logger(NULL, MESHLINK_ERROR, "Cannot create configuration directory %s: %s", mesh->confbase, strerror(errno));
+		meshlink_close(mesh);
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return NULL;
+	}
+
+	char path[PATH_MAX];
+	snprintf(path, sizeof(path), "%s" SLASH "meshlink.lock", mesh->confbase);
+
+	mesh->lockfile = fopen(path, "w+");
+
+	if(!mesh->lockfile) {
+		logger(NULL, MESHLINK_ERROR, "Cannot not open %s: %s\n", path, strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
+
+#ifdef FD_CLOEXEC
+	fcntl(fileno(mesh->lockfile), F_SETFD, FD_CLOEXEC);
+#endif
+
+#ifdef HAVE_MINGW
+	// TODO: use _locking()?
+#else
+
+	if(flock(fileno(mesh->lockfile), LOCK_EX | LOCK_NB) != 0) {
+		logger(NULL, MESHLINK_ERROR, "Cannot lock %s: %s\n", path, strerror(errno));
+		fclose(mesh->lockfile);
+		mesh->lockfile = 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->lockfile) {
+		fclose(mesh->lockfile);
+		mesh->lockfile = NULL;
+	}
+}
+
+/// 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;
+	}
+
+	uint8_t *buf = xmalloc(len);
+
+	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;
+		}
+	}
+
+	config->buf = buf;
+	config->len = len;
+
+	return true;
+}
+
+/// 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;
+
+			if(!success) {
+				logger(mesh, MESHLINK_ERROR, "Cannot write config file: %s", strerror(errno));
+			}
+
+			meshlink_errno = MESHLINK_ESTORAGE;
+		} 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(fflush(f)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to flush 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));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		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;
+}
+
+/// 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;
+	}
+
+	char path[PATH_MAX];
+	make_host_path(mesh, conf_subdir, name, 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;
+}
+
+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;
+}
+
+/// 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));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		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(fclose(f)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to close `%s': %s", tmp_path, strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
+
+	if(rename(tmp_path, path)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to rename `%s' to `%s': %s", tmp_path, path, strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
+
+	return true;
+}
+
+/// Delete a host configuration file.
+bool config_delete(meshlink_handle_t *mesh, const char *conf_subdir, const char *name) {
+	assert(conf_subdir);
+	assert(name);
+
+	if(!mesh->confbase) {
+		return true;
+	}
+
+	char path[PATH_MAX];
+	make_host_path(mesh, conf_subdir, name, path, sizeof(path));
+
+	if(unlink(path) && errno != ENOENT) {
+		logger(mesh, MESHLINK_ERROR, "Failed to unlink `%s': %s", path, strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
+
+	return true;
+}
+
+/// 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;
+}
+
+/// 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(!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));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		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(rename(tmp_path, path)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to rename `%s' to `%s': %s", tmp_path, path, strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		fclose(f);
+		return false;
+	}
+
+	if(fclose(f)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to close `%s': %s", tmp_path, strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		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);
+
+	if(unlink(used_path)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to unlink `%s': %s", path, strerror(errno));
+		return false;
+	}
+
+	snprintf(path, sizeof(path), "%s" SLASH "%s" SLASH "invitations", mesh->confbase, conf_subdir);
+
+	if(!sync_path(path)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to sync `%s': %s", path, strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
+
+	return true;
+}
+
+/// 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));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		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(fclose(f)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to close `%s': %s", path, strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
+
+	snprintf(path, sizeof(path), "%s" SLASH "%s" SLASH "invitations", mesh->confbase, conf_subdir);
+
+	if(!sync_path(path)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to sync `%s': %s", path, strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
+
+	return true;
+}
+
+/// 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;
 }