Native Client side changes for debugging support: stdout/err -> postmessage.

src/trusted/service_runtime/nacl_desc_postmessage.c

+/*
+ * Copyright (c) 2011 The Native Client Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/*
+ * Subclass of NaClDesc which passes write output data to the browser
+ * using the reverse channel, to (eventually) show up as PostMessage
+ * data.
+ *
+ * A NaClDescPostMessage object pretends to be a character device, so
+ * that I/O packages that fstat to determine buffering strategy will
+ * work correctly.  The only other syscall that it implements is
+ * write, and the data is sent through the reverse channel interface
+ * to the browser's JavaScript environment.
+ */
+
+#include <string.h>
+
+#include "native_client/src/trusted/service_runtime/nacl_desc_postmessage.h"
+
+#include "native_client/src/shared/platform/nacl_check.h"
+#include "native_client/src/shared/platform/nacl_sync.h"
+#include "native_client/src/shared/platform/nacl_sync_checked.h"
+#include "native_client/src/trusted/reverse_service/reverse_control_rpc.h"
+#include "native_client/src/trusted/service_runtime/include/sys/errno.h"
+#include "native_client/src/trusted/service_runtime/include/sys/stat.h"
+#include "native_client/src/trusted/service_runtime/sel_ldr.h"
+
+
+static struct NaClDescVtbl const kNaClDescPostMessageVtbl;  /* fwd */
+
+int NaClDescPostMessageCtor(struct NaClDescPostMessage  *self,
+                            struct NaClApp              *nap) {
+  NaClLog(4, "Entered NaClDescPostMessageCtor\n");
+  NACL_VTBL(NaClRefCount, self) = (struct NaClRefCountVtbl const *) NULL;
+  if (!NaClDescCtor(&self->base)) {
+    NaClLog(4, "Leaving NaClDescPostMessageCtor: failed\n");
+    return 0;
+  }
+  self->nap = nap;
+  self->error = 0;
+  NACL_VTBL(NaClRefCount, self) =
+      (struct NaClRefCountVtbl const *) &kNaClDescPostMessageVtbl;
+  NaClLog(4, " Write vfptr = %"NACL_PRIxPTR"\n",
+          (uintptr_t) NACL_VTBL(NaClDesc, self)->Write);
+  NaClLog(4, "Leaving NaClDescPostMessageCtor: success\n");
+  return 1;
+}
+
+static void NaClDescPostMessageDtor(struct NaClRefCount *vself) {
+  struct NaClDescPostMessage  *self = (struct NaClDescPostMessage *) vself;
+
+  NaClLog(4, "Entered NaClDescPostMessageDtor\n");
+  self->nap = NULL;
+  NACL_VTBL(NaClRefCount, vself) =
+      (struct NaClRefCountVtbl const *) &kNaClDescVtbl;
+  (*NACL_VTBL(NaClRefCount, vself)->Dtor)(vself);
+  NaClLog(4, "Leaving NaClDescPostMessageDtor\n");
+}
+
+static ssize_t NaClDescPostMessageWrite(struct NaClDesc *vself,
+                                        void const      *buf,
+                                        size_t          len) {
+  struct NaClDescPostMessage  *self = (struct NaClDescPostMessage *) vself;
+  NaClSrpcError               rpc_result;
+  int                         num_written = 0;
+  ssize_t                     rv = -NACL_ABI_EIO;
+
+  NaClLog(4, "Entered NaClDescPostMessageWrite(..., %"NACL_PRIuS")\n", len);
+  if (0 != self->error) {
+    return self->error;
+  }
+  NaClXMutexLock(&self->nap->mu);
+  if (NACL_REVERSE_CHANNEL_INITIALIZED !=
+      self->nap->reverse_channel_initialization_state) {
+    NaClLog(LOG_FATAL,
+            "NaClDescPostMessageWrite: Reverse channel not initialized\n");
+  }
+  if (len > NACL_ABI_SIZE_T_MAX) {
+    len = NACL_ABI_SIZE_T_MAX;  /* fits in an int32_t */
+  }
+  rpc_result = NaClSrpcInvokeBySignature(&self->nap->reverse_channel,
+                                         NACL_REVERSE_CONTROL_POST_MESSAGE,
+                                         len,
+                                         buf,
+                                         &num_written);
+  if (NACL_SRPC_RESULT_OK != rpc_result || num_written > (int) len) {
+    /*
+     * A conforming interface implementation could return an errno,
+     * but should never return a larger value.
+     */
+    rv = -NACL_ABI_EIO;
+    /*
+     * make this error permanent; other negative errno returns are
+     * considered transient.
+     */
+    self->error = rv;
+    goto error_exit;
+  }
+  rv = (ssize_t) num_written;
+ error_exit:
+  NaClXMutexUnlock(&self->nap->mu);
+  NaClLog(4, "Leaving NaClDescPostMessageWrite (%"NACL_PRIuS")\n", rv);
+  return rv;
+}
+
+static int NaClDescPostMessageFstat(struct NaClDesc       *vself,
+                                    struct nacl_abi_stat  *statbuf) {
+  UNREFERENCED_PARAMETER(vself);
+
+  memset(statbuf, 0, sizeof *statbuf);
+  statbuf->nacl_abi_st_ino = NACL_FAKE_INODE_NUM;
+  statbuf->nacl_abi_st_mode = (NACL_ABI_S_IFCHR | NACL_ABI_S_IWUSR);
+  statbuf->nacl_abi_st_nlink = 1;
+  statbuf->nacl_abi_st_uid = -1;
+  statbuf->nacl_abi_st_gid = -1;
+  return 0;
+}
+
+static struct NaClDescVtbl const kNaClDescPostMessageVtbl = {
+  {
+    NaClDescPostMessageDtor,
+  },
+  NaClDescMapNotImplemented,
+  NaClDescUnmapUnsafeNotImplemented,
+  NaClDescUnmapNotImplemented,
+  NaClDescReadNotImplemented,
+  NaClDescPostMessageWrite,
+  NaClDescSeekNotImplemented,
+  NaClDescIoctlNotImplemented,
+  NaClDescPostMessageFstat,
+  NaClDescGetdentsNotImplemented,
+  NACL_DESC_DEVICE_POSTMESSAGE,
+  NaClDescExternalizeSizeNotImplemented,
+  NaClDescExternalizeNotImplemented,
+  NaClDescLockNotImplemented,
+  NaClDescTryLockNotImplemented,
+  NaClDescUnlockNotImplemented,
+  NaClDescWaitNotImplemented,
+  NaClDescTimedWaitAbsNotImplemented,
+  NaClDescSignalNotImplemented,
+  NaClDescBroadcastNotImplemented,
+  NaClDescSendMsgNotImplemented,
+  NaClDescRecvMsgNotImplemented,
+  NaClDescConnectAddrNotImplemented,
+  NaClDescAcceptConnNotImplemented,
+  NaClDescPostNotImplemented,
+  NaClDescSemWaitNotImplemented,
+  NaClDescGetValueNotImplemented,
+};