diff options
| -rw-r--r-- | fs/common.c | 4 | ||||
| -rw-r--r-- | fs/common.h | 16 | ||||
| -rw-r--r-- | fs/tabfs.c | 4 | ||||
| -rw-r--r-- | fs/ws.c | 8 |
4 files changed, 28 insertions, 4 deletions
diff --git a/fs/common.c b/fs/common.c index 7281147..c2bf3dd 100644 --- a/fs/common.c +++ b/fs/common.c @@ -16,6 +16,10 @@ void common_init() { if (pipe(ws_to_tabfs)) exit(1); } +// FIXME: we probably need memory fences here?? especially on +// non-x86?? idk +// see https://stackoverflow.com/questions/35837539/does-the-use-of-an-anonymous-pipe-introduce-a-memory-barrier-for-interthread-com + void common_send_tabfs_to_ws(char *request_data) { write(tabfs_to_ws[1], &request_data, sizeof(request_data)); } diff --git a/fs/common.h b/fs/common.h index 79fd9f3..7004c7b 100644 --- a/fs/common.h +++ b/fs/common.h @@ -1,3 +1,6 @@ +// common provides an interface for tabfs.c (which talks to FUSE) to +// talk to ws.c (which talks to the browser over WebSocket). + #ifndef COMMON_H #define COMMON_H @@ -9,7 +12,20 @@ void common_init(); typedef int (*fd_set_filler_fn_t)(fd_set*, fd_set*, fd_set*); +// All send and receive calls are blocking! + void common_send_tabfs_to_ws(char *request_data); +// This function is called by the ws thread; it blocks waiting for +// tabfs thread to send a request _from FUSE_, which means that the ws +// thread wouldn't be able to hear about events _from the browser_ +// while blocked here (including important ones, like 'the browser +// wants to connect to us!'). +// +// The hack solution is that ws passes a function `filler` to add the +// WebSocket file descriptors to the set that +// `common_receive_tabfs_to_ws` polls, so it _also_ waits on +// _browser-side_ events from the WebSocket file descriptors, not just +// FUSE-side events. char *common_receive_tabfs_to_ws(fd_set_filler_fn_t filler); void common_send_ws_to_tabfs(char *response_data); @@ -12,7 +12,8 @@ #include "ws.h" static cJSON *send_request_then_await_response(cJSON *req) { - char *request_data = cJSON_Print(req); // Will be freed on ws side. + // Will be freed at receiver (ws.c, receive_tabfs_request_then_send_to_browser). + char *request_data = cJSON_Print(req); common_send_tabfs_to_ws(request_data); char *response_data = common_receive_ws_to_tabfs(); @@ -22,6 +23,7 @@ static cJSON *send_request_then_await_response(cJSON *req) { } cJSON *resp = cJSON_Parse((const char *) response_data); + // Was allocated by sender (ws.c, websocket_frame). free(response_data); return resp; @@ -37,20 +37,22 @@ static int fill_fd_set_with_ws_sockets(fd_set *read_fds, fd_set *write_fds, fd_s static void receive_tabfs_request_then_send_to_browser() { char *request_data = common_receive_tabfs_to_ws(fill_fd_set_with_ws_sockets); if (request_data == NULL) { - return; + goto done; } if (con == NULL) { common_send_ws_to_tabfs(NULL); - return; + goto done; } wby_frame_begin(con, WBY_WSOP_TEXT_FRAME); wby_write(con, request_data, strlen(request_data)); wby_frame_end(con); + done: // Was allocated by sender (tabfs.c, send_request_then_await_response). - free(request_data); + if (request_data != NULL) { free(request_data); } + return; } static int |