Added arbitrary length terminal write and read with early return

include/aos/aos_rpc.h

@@ -28,6 +28,7 @@ enum rpc_mtype {
     RPC_MTYPE_SERIAL_GETCHAR,
     RPC_MTYPE_SERIAL_PUTCHAR,
     RPC_MTYPE_SERIAL_WRITE,
+    RPC_MTYPE_SERIAL_READ,
     RPC_MTYPE_PROCESS_SPAWN,
     RPC_MTYPE_PROCESS_GET_NAME,
     RPC_MTYPE_PROCESS_GET_ALL_PIDS,
@@ -82,9 +83,16 @@ errval_t aos_rpc_serial_putchar(struct aos_rpc *chan, char c);
 /**
  * \brief Send a list of characters to the serial port
  */
-errval_t aos_rpc_serial_write(struct aos_rpc *chan, const char *buf, 
+size_t aos_rpc_serial_write(struct aos_rpc *chan, const char *buf,
                             size_t buf_len);
 
+/**
+ * \brief Read a list of characters from the serial port
+ */
+size_t aos_rpc_serial_read(struct aos_rpc *rpc, char *buf,
+                           size_t buf_len);
+
+
 /**
  * \brief Request that the process manager start a new process
  * \arg cmdline the name of the process that needs to be spawned (without a

lib/aos/aos_rpc.c

@@ -126,34 +126,77 @@ aos_rpc_serial_putchar(struct aos_rpc *rpc, char c) {
     );
 }
 
-// putchar for terminal printing is too slow so we send buffers instead
-errval_t
+// putchar for terminal printing is too slow so we write buffers instead
+// the corresponding interface does not know about errors, just partial writes
+size_t
 aos_rpc_serial_write(struct aos_rpc *rpc, const char *buf, size_t buf_len) {
     errval_t err;
 
     // split the buffer into chunks for sending
+    size_t total_bytes = 0;
     while(buf_len > 0) {
-        size_t chunk_len = buf_len;
-        if (chunk_len > RPC_SHARED_SIZE) {
-            chunk_len = RPC_SHARED_SIZE;
-        }
+        size_t chunk_len = MIN(buf_len, RPC_SHARED_SIZE);
 
         memcpy(rpc->shared_mem, buf, chunk_len);
 
+        size_t written_bytes;
         err = do_aos_rpc(
             rpc, RPC_MTYPE_SERIAL_WRITE,
             NULL_CAP, chunk_len, 0, 0,
-            NULL, NULL, NULL, NULL
+            NULL, NULL, &written_bytes, NULL
         );
         if (err_is_fail(err)) {
-            return err;
+            return total_bytes;
+        }
+
+        total_bytes += written_bytes;
+
+        // if the receiver was not able to write all we have given, return for now
+        if (written_bytes < chunk_len) {
+            return total_bytes;
         }
 
         buf += chunk_len;
         buf_len -= chunk_len;
     }
 
-    return SYS_ERR_OK;
+    return total_bytes;
+}
+
+// getchar for terminal reading is too slow so we read buffers instead
+// the corresponding interface does not know about errors, just partial reads
+size_t
+aos_rpc_serial_read(struct aos_rpc *rpc, char *buf, size_t buf_len) {
+    errval_t err;
+
+    // split the buffer into chunks for reading
+    size_t total_bytes = 0;
+    while(buf_len > 0) {
+        size_t chunk_len = MIN(buf_len, RPC_SHARED_SIZE);
+
+        size_t read_bytes;
+        err = do_aos_rpc(
+            rpc, RPC_MTYPE_SERIAL_WRITE,
+            NULL_CAP, 0, chunk_len, 0,
+            NULL, NULL, &read_bytes, NULL
+        );
+        if (err_is_fail(err)) {
+            return total_bytes;
+        }
+
+        memcpy(buf, rpc->shared_mem, read_bytes);
+        total_bytes += read_bytes;
+
+        // if the receiver was not able to write all we have given, return for now
+        if (read_bytes < chunk_len) {
+            return total_bytes;
+        }
+
+        buf += chunk_len;
+        buf_len -= chunk_len;
+    }
+
+    return total_bytes;
 }
 
 errval_t

lib/aos/init.c

@@ -83,17 +83,6 @@ static size_t dummy_terminal_read(char *buf, size_t len)
     return 0;
 }
 
-static int event_init_dispatch_thread(void *arg)
-{
-    errval_t err;
-    while(true) {
-        err = event_dispatch(get_default_waitset());
-        if (err_is_fail(err)) {
-            USER_PANIC_ERR(err_push(err, LIB_ERR_EVENT_DISPATCH), "Failed to dispatch events");
-        }
-    }
-}
-
 static void handle_init_recv(void *arg)
 {
     errval_t err;
@@ -115,27 +104,29 @@ static void handle_init_recv(void *arg)
 // TODO rueegges: allow partial write
 static size_t aos_terminal_write(const char *buf, size_t len)
 {
-    errval_t err;
+    if(len == 0) return 0;
+
     struct aos_rpc *rpc = aos_rpc_get_serial_channel();
     if (rpc == NULL) {
-        debug_printf("Attempted to printf before initializing rpc: %.*s\n", len, buf);
-        USER_PANIC("Make sure to initialize rpc before function barrelfish_libc_glue_init is called.");
-        return len;
+        debug_printf("[aos_terminal_write] RPC NOT YET INITIALIZED: %.*s\n", len, buf);
+        USER_PANIC("Make sure to initialize aos_rpc before barrelfish_libc_glue_init is called.");
     }
 
-    err = aos_rpc_serial_write(rpc, buf, len);
-    assert(err_is_ok(err));
-    return len;
+    return aos_rpc_serial_write(rpc, buf, len);
 }
 
 // TODO rueegges: make more efficient?
 static size_t aos_terminal_read(char *buf, size_t len)
 {
-    errval_t err;
+    if(len == 0) return 0;
+
     struct aos_rpc *rpc = aos_rpc_get_serial_channel();
-    err = aos_rpc_serial_getchar(rpc, buf);
-    assert(err_is_ok(err));
-    return 1;
+    if (rpc == NULL) {
+        debug_printf("[aos_terminal_read] RPC NOT YET INITIALIZED: %.*s\n", len, buf);
+        USER_PANIC("Make sure to initialize aos_rpc before barrelfish_libc_glue_init is called.");
+    }
+
+    return aos_rpc_serial_read(rpc, buf, len);
 }
 
 /* Set libc function pointers */
@@ -250,9 +241,6 @@ errval_t barrelfish_init_onthread(struct spawn_domain_params *params)
     /* set init RPC client in our program state */
     set_init_rpc(init_rpc);
 
-    // create thread to dispatch events
-    thread_create(event_init_dispatch_thread, NULL);
-
     /* TODO MILESTONE 3: now we should have a channel with init set up and can
      * use it for the ram allocator */
 

lib/spawn/rpc_server.c

@@ -166,15 +166,30 @@ static errval_t handle_rpc_serial_write(
     struct capref arg_cap, size_t arg_size, uintptr_t arg0, uintptr_t arg1,
     struct capref *ret_cap, size_t *ret_size, uintptr_t *ret0, uintptr_t *ret1
 ) {
-    if (arg_size == 0 ) {
-        return ERR_INVALID_ARGS;
-    }
-
     // MARKER SHELL: Replace with UART call
     for (size_t i = 0; i < arg_size; ++i){
         putchar(((char *)rpc->shared_mem)[i]);
     }
 
+    // return the number of characters written. Important for UART for early return when the buffer is full
+    *ret0 = arg_size;
+
+    return SYS_ERR_OK;
+}
+
+static errval_t handle_rpc_serial_read(
+    struct aos_rpc_server *rpc,
+    struct capref arg_cap, size_t arg_size, uintptr_t arg0, uintptr_t arg1,
+    struct capref *ret_cap, size_t *ret_size, uintptr_t *ret0, uintptr_t *ret1
+) {
+    // MARKER SHELL: Replace with UART call
+    for (size_t i = 0; i < arg_size; ++i){
+        ((char *)rpc->shared_mem)[i] = getchar();
+    }
+
+    // return the number of characters read. Important for UART for early return when the buffer is empty
+    *ret0 = arg_size;
+
     return SYS_ERR_OK;
 }
 
@@ -268,6 +283,7 @@ static rpc_handler_t rpc_handlers[RPC_MTYPE_COUNT] = {
     [RPC_MTYPE_SERIAL_GETCHAR] = handle_rpc_serial_getchar,
     [RPC_MTYPE_SERIAL_PUTCHAR] = handle_rpc_serial_putchar,
     [RPC_MTYPE_SERIAL_WRITE] = handle_rpc_serial_write,
+    [RPC_MTYPE_SERIAL_READ] = handle_rpc_serial_read,
     [RPC_MTYPE_PROCESS_SPAWN] = handle_rpc_process_spawn,
     [RPC_MTYPE_PROCESS_GET_NAME] = handle_rpc_process_get_name,
     [RPC_MTYPE_PROCESS_GET_ALL_PIDS] = handle_rpc_process_get_all_pids,