Use a separate lockfile to lock the configuration directory.

[meshlink] / src / conf.c

diff --git a/src/conf.c b/src/conf.c
index ca107b0a062c6dc5470dab09e8da44a909a0b4f4..7f92048ce30603245946a047a264172861a2e304 100644 (file)
--- a/src/conf.c
+++ b/src/conf.c
@@ -96,7 +96,7 @@ static void deltree(const char *dirname) {
        rmdir(dirname);
 }
 
-static bool sync_path(const char *pathname) {
+bool sync_path(const char *pathname) {
        assert(pathname);
 
        int fd = open(pathname, O_RDONLY);
@@ -153,11 +153,6 @@ bool config_init(meshlink_handle_t *mesh, const char *conf_subdir) {
                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
@@ -191,7 +186,7 @@ bool config_destroy(const char *confbase, const char *conf_subdir) {
        assert(conf_subdir);
 
        if(!confbase) {
-               return false;
+               return true;
        }
 
        struct stat st;
@@ -456,35 +451,42 @@ bool meshlink_confbase_exists(meshlink_handle_t *mesh) {
        return confbase_exists;
 }
 
-/// Lock the main configuration file.
+/// 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];
-       make_main_path(mesh, "current", path, sizeof(path));
+       snprintf(path, sizeof(path), "%s" SLASH "meshlink.lock", mesh->confbase);
 
-       mesh->conffile = fopen(path, "r");
+       mesh->lockfile = fopen(path, "w+");
 
-       if(!mesh->conffile) {
+       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->conffile), F_SETFD, FD_CLOEXEC);
+       fcntl(fileno(mesh->lockfile), F_SETFD, FD_CLOEXEC);
 #endif
 
 #ifdef HAVE_MINGW
        // TODO: use _locking()?
 #else
 
-       if(flock(fileno(mesh->conffile), LOCK_EX | LOCK_NB) != 0) {
+       if(flock(fileno(mesh->lockfile), LOCK_EX | LOCK_NB) != 0) {
                logger(NULL, MESHLINK_ERROR, "Cannot lock %s: %s\n", path, strerror(errno));
-               fclose(mesh->conffile);
-               mesh->conffile = NULL;
+               fclose(mesh->lockfile);
+               mesh->lockfile = NULL;
                meshlink_errno = MESHLINK_EBUSY;
                return false;
        }
@@ -496,9 +498,9 @@ bool main_config_lock(meshlink_handle_t *mesh) {
 
 /// Unlock the main configuration file.
 void main_config_unlock(meshlink_handle_t *mesh) {
-       if(mesh->conffile) {
-               fclose(mesh->conffile);
-               mesh->conffile = NULL;
+       if(mesh->lockfile) {
+               fclose(mesh->lockfile);
+               mesh->lockfile = NULL;
        }
 }