Handle too-short write(3)s in mod_json_cdr

write(3) can write fewer bytes than was requested for any number of
reasons.  The correct behavior is to retry unless there is an error.

If there is an error, try to unlink the file; no sense in leaving
corrupted data laying around.

src/mod/event_handlers/mod_json_cdr/mod_json_cdr.c

@@ -213,11 +213,15 @@ static void backup_cdr(cdr_data_t *data)
 				mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
 #endif 
 				if ((fd = open(path, O_WRONLY | O_CREAT | O_TRUNC, mode)) > -1) { 
-					int wrote = write(fd, json_text, (unsigned) strlen(json_text));
-					close(fd);
-					fd = -1;
-					if (wrote < 0) {
+					switch_size_t json_len = strlen(json_text);
+					switch_ssize_t wrote = 0, x;
+					do { x = write(fd, json_text, json_len);
+					} while (!(x<0) && json_len > (wrote += x));
+					close(fd); fd = -1;
+					if (x < 0) {
 						switch_log_printf(SWITCH_CHANNEL_UUID_LOG(data->uuid), SWITCH_LOG_ERROR, "Error writing [%s]\n",path);
+						if (0 > unlink(path))
+							switch_log_printf(SWITCH_CHANNEL_UUID_LOG(data->uuid), SWITCH_LOG_ERROR, "Error unlinking [%s]\n",path);
 					}
 					switch_safe_free(path);
 					break;
@@ -273,11 +277,15 @@ static void process_cdr(cdr_data_t *data)
 #else
 			if ((fd = open(path, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH)) > -1) {
 #endif
-				int wrote = write(fd, data->json_text, (unsigned) strlen(data->json_text));
-				close(fd);
-				fd = -1;
-				if (wrote < 0) {
+				switch_size_t json_len = strlen(data->json_text);
+				switch_ssize_t wrote = 0, x;
+				do { x = write(fd, data->json_text, json_len);
+				} while (!(x<0) && json_len > (wrote += x));
+				close(fd); fd = -1;
+				if (x < 0) {
 					switch_log_printf(SWITCH_CHANNEL_UUID_LOG(data->uuid), SWITCH_LOG_ERROR, "Error writing [%s]\n",path);
+					if (0 > unlink(path))
+						switch_log_printf(SWITCH_CHANNEL_UUID_LOG(data->uuid), SWITCH_LOG_ERROR, "Error unlinking [%s]\n",path);
 				}
 			} else {
 				char ebuf[512] = { 0 };