diff options
-rw-r--r-- | src/modules/systemlib/param/param.c | 85 |
1 files changed, 42 insertions, 43 deletions
diff --git a/src/modules/systemlib/param/param.c b/src/modules/systemlib/param/param.c index ccdb2ea38..398657dd7 100644 --- a/src/modules/systemlib/param/param.c +++ b/src/modules/systemlib/param/param.c @@ -508,64 +508,63 @@ param_get_default_file(void) int param_save_default(void) { - int result; - unsigned retries = 0; - - /* delete the file in case it exists */ - struct stat buffer; - if (stat(param_get_default_file(), &buffer) == 0) { - - do { - result = unlink(param_get_default_file()); - if (result != 0) { - retries++; - usleep(1000 * retries); - } - } while (result != OK && retries < 10); + int res; + int fd; - if (result != OK) - warnx("unlinking file %s failed.", param_get_default_file()); - } + const char *filename = param_get_default_file(); + const char *filename_tmp = malloc(strlen(filename) + 5); + sprintf(filename_tmp, "%s.tmp", filename); - /* create the file */ - int fd; + /* delete temp file if exist */ + res = unlink(filename_tmp); + + if (res != OK && errno == ENOENT) + res = OK; + + if (res != OK) + warn("failed to delete temp file: %s", filename_tmp); + + if (res == OK) { + /* write parameters to temp file */ + fd = open(filename_tmp, O_WRONLY | O_CREAT | O_EXCL); - do { - /* do another attempt in case the unlink call is not synced yet */ - fd = open(param_get_default_file(), O_WRONLY | O_CREAT | O_EXCL); if (fd < 0) { - retries++; - usleep(1000 * retries); + warn("failed to open temp file: %s", filename_tmp); + res = ERROR; } - } while (fd < 0 && retries < 10); + if (res == OK) { + res = param_export(fd, false); - if (fd < 0) { - - warn("opening '%s' for writing failed", param_get_default_file()); - return fd; - } + if (res != OK) + warnx("failed to write parameters to file: %s", filename_tmp); + } - do { - result = param_export(fd, false); + close(fd); + } - if (result != OK) { - retries++; - usleep(1000 * retries); - } + if (res == OK) { + /* delete parameters file */ + res = unlink(filename); - } while (result != 0 && retries < 10); + if (res != OK && errno == ENOENT) + res = OK; + if (res != OK) + warn("failed to delete parameters file: %s", filename); + } - close(fd); + if (res == OK) { + /* rename temp file to parameters */ + res = rename(filename_tmp, filename); - if (result != OK) { - warn("error exporting parameters to '%s'", param_get_default_file()); - (void)unlink(param_get_default_file()); - return result; + if (res != OK) + warn("failed to rename %s to %s", filename_tmp, filename); } - return 0; + free(filename_tmp); + + return res; } /** |