p2p: Use p2p for updates
This is the main patch for enabling use of p2p for consuming and/or
sharing updates via p2p. Refer to the ddoc and other documentation for
how this works.
BUG=chromium:260426,chromium:273110
TEST=New unit tests + unit tests pass + manual testing
Change-Id: I6bc3bddae1e041ccc176969a651396e8e89cb3f0
Reviewed-on: https://chromium-review.googlesource.com/64829
Reviewed-by: David Zeuthen <zeuthen@chromium.org>
Commit-Queue: David Zeuthen <zeuthen@chromium.org>
Tested-by: David Zeuthen <zeuthen@chromium.org>
diff --git a/download_action.cc b/download_action.cc
index da6b1fc..17d4538 100644
--- a/download_action.cc
+++ b/download_action.cc
@@ -8,12 +8,19 @@
#include <string>
#include <vector>
#include <glib.h>
+
+#include <base/file_path.h>
+#include <base/stringprintf.h>
+
#include "update_engine/action_pipe.h"
+#include "update_engine/p2p_manager.h"
#include "update_engine/subprocess.h"
using std::min;
using std::string;
using std::vector;
+using base::FilePath;
+using base::StringPrintf;
namespace chromeos_update_engine {
@@ -29,10 +36,118 @@
writer_(NULL),
code_(kErrorCodeSuccess),
delegate_(NULL),
- bytes_received_(0) {}
+ bytes_received_(0),
+ p2p_sharing_fd_(-1),
+ p2p_visible_(true) {}
DownloadAction::~DownloadAction() {}
+void DownloadAction::CloseP2PSharingFd(bool delete_p2p_file) {
+ if (p2p_sharing_fd_ != -1) {
+ if (close(p2p_sharing_fd_) != 0) {
+ PLOG(ERROR) << "Error closing p2p sharing fd";
+ }
+ p2p_sharing_fd_ = -1;
+ }
+
+ if (delete_p2p_file) {
+ FilePath path = system_state_->p2p_manager()->FileGetPath(p2p_file_id_);
+ if (unlink(path.value().c_str()) != 0) {
+ PLOG(ERROR) << "Error deleting p2p file " << path.value();
+ } else {
+ LOG(INFO) << "Deleted p2p file " << path.value();
+ }
+ }
+
+ // Don't use p2p from this point onwards.
+ p2p_file_id_.clear();
+}
+
+bool DownloadAction::SetupP2PSharingFd() {
+ P2PManager *p2p_manager = system_state_->p2p_manager();
+
+ if (!p2p_manager->FileShare(p2p_file_id_, install_plan_.payload_size)) {
+ LOG(ERROR) << "Unable to share file via p2p";
+ CloseP2PSharingFd(true); // delete p2p file
+ return false;
+ }
+
+ // File has already been created (and allocated, xattrs been
+ // populated etc.) by FileShare() so just open it for writing.
+ FilePath path = p2p_manager->FileGetPath(p2p_file_id_);
+ p2p_sharing_fd_ = open(path.value().c_str(), O_WRONLY);
+ if (p2p_sharing_fd_ == -1) {
+ PLOG(ERROR) << "Error opening file " << path.value();
+ CloseP2PSharingFd(true); // Delete p2p file.
+ return false;
+ }
+
+ // Ensure file to share is world-readable, otherwise
+ // p2p-server and p2p-http-server can't access it.
+ //
+ // (Q: Why doesn't the file have mode 0644 already? A: Because
+ // the process-wide umask is set to 0700 in main.cc.)
+ if (fchmod(p2p_sharing_fd_, 0644) != 0) {
+ PLOG(ERROR) << "Error setting mode 0644 on " << path.value();
+ CloseP2PSharingFd(true); // Delete p2p file.
+ return false;
+ }
+
+ // All good.
+ LOG(INFO) << "Writing payload contents to " << path.value();
+ p2p_manager->FileGetVisible(p2p_file_id_, &p2p_visible_);
+ return true;
+}
+
+void DownloadAction::WriteToP2PFile(const char *data,
+ size_t length,
+ off_t file_offset) {
+ if (p2p_sharing_fd_ == -1) {
+ if (!SetupP2PSharingFd())
+ return;
+ }
+
+ // Check that the file is at least |file_offset| bytes long - if
+ // it's not something is wrong and we must immediately delete the
+ // file to avoid propagating this problem to other peers.
+ //
+ // How can this happen? It could be that we're resuming an update
+ // after a system crash... in this case, it could be that
+ //
+ // 1. the p2p file didn't get properly synced to stable storage; or
+ // 2. the file was deleted at bootup (it's in /var/cache after all); or
+ // 3. other reasons
+ struct stat statbuf;
+ if (fstat(p2p_sharing_fd_, &statbuf) != 0) {
+ PLOG(ERROR) << "Error getting file status for p2p file";
+ CloseP2PSharingFd(true); // Delete p2p file.
+ return;
+ }
+ if (statbuf.st_size < file_offset) {
+ LOG(ERROR) << "Wanting to write to file offset " << file_offset
+ << " but existing p2p file is only " << statbuf.st_size
+ << " bytes.";
+ CloseP2PSharingFd(true); // Delete p2p file.
+ return;
+ }
+
+ off_t cur_file_offset = lseek(p2p_sharing_fd_, file_offset, SEEK_SET);
+ if (cur_file_offset != static_cast<off_t>(file_offset)) {
+ PLOG(ERROR) << "Error seeking to position "
+ << file_offset << " in p2p file";
+ CloseP2PSharingFd(true); // Delete p2p file.
+ } else {
+ // OK, seeking worked, now write the data
+ ssize_t bytes_written = write(p2p_sharing_fd_, data, length);
+ if (bytes_written != static_cast<ssize_t>(length)) {
+ PLOG(ERROR) << "Error writing "
+ << length << " bytes at file offset "
+ << file_offset << " in p2p file";
+ CloseP2PSharingFd(true); // Delete p2p file.
+ }
+ }
+}
+
void DownloadAction::PerformAction() {
http_fetcher_->set_delegate(this);
@@ -72,6 +187,33 @@
if (delegate_) {
delegate_->SetDownloadStatus(true); // Set to active.
}
+
+ if (system_state_ != NULL) {
+ string file_id = utils::CalculateP2PFileId(install_plan_.payload_hash,
+ install_plan_.payload_size);
+ if (system_state_->request_params()->use_p2p_for_sharing()) {
+ // If we're sharing the update, store the file_id to convey
+ // that we should write to the file.
+ p2p_file_id_ = file_id;
+ LOG(INFO) << "p2p file id: " << p2p_file_id_;
+ } else {
+ // Even if we're not sharing the update, it could be that
+ // there's a partial file from a previous attempt with the same
+ // hash. If this is the case, we NEED to clean it up otherwise
+ // we're essentially timing out other peers downloading from us
+ // (since we're never going to complete the file).
+ FilePath path = system_state_->p2p_manager()->FileGetPath(file_id);
+ if (!path.empty()) {
+ if (unlink(path.value().c_str()) != 0) {
+ PLOG(ERROR) << "Error deleting p2p file " << path.value();
+ } else {
+ LOG(INFO) << "Deleting partial p2p file " << path.value()
+ << " since we're not using p2p to share.";
+ }
+ }
+ }
+ }
+
http_fetcher_->BeginTransfer(install_plan_.download_url);
}
@@ -83,6 +225,7 @@
if (delegate_) {
delegate_->SetDownloadStatus(false); // Set to inactive.
}
+ CloseP2PSharingFd(false); // Keep p2p file.
// Terminates the transfer. The action is terminated, if necessary, when the
// TransferTerminated callback is received.
http_fetcher_->TerminateTransfer();
@@ -95,6 +238,11 @@
void DownloadAction::ReceivedBytes(HttpFetcher *fetcher,
const char* bytes,
int length) {
+ // Note that bytes_received_ is the current offset.
+ if (!p2p_file_id_.empty()) {
+ WriteToP2PFile(bytes, length, bytes_received_);
+ }
+
bytes_received_ += length;
if (delegate_)
delegate_->BytesReceived(bytes_received_, install_plan_.payload_size);
@@ -107,6 +255,15 @@
TerminateProcessing();
return;
}
+
+ // Call p2p_manager_->FileMakeVisible() when we've successfully
+ // verified the manifest!
+ if (!p2p_visible_ &&
+ delta_performer_.get() && delta_performer_->IsManifestValid()) {
+ LOG(INFO) << "Manifest has been validated. Making p2p file visible.";
+ system_state_->p2p_manager()->FileMakeVisible(p2p_file_id_);
+ p2p_visible_ = true;
+ }
}
void DownloadAction::TransferComplete(HttpFetcher *fetcher, bool successful) {