[cdc_rsync] Detect remote architecture (#86)

Improves ServerArch so that it can detect the remote architecture by running uname and checking %PROCESSOR_ARCHITECTURE%. So far, only x64 Linux and x64 Windows are supported, but in the future it is easy to add support for others, e.g. aarch64, as well. Before the detection is run, the remote architecture is guessed first based on the destination. For instance, if the destination directory starts with "C:\", it pretty much means Windows. If cdc_rsync_server exists and runs fine, there's no need for detection. Since also PortManager depends on the remote architecture, it has to be adjusted as well. So far, PortManager assumeed that "local" means Windows and "remote" means Linux. This is no longer the case for syncing to Windows devices, so this CL adds the necessary abstractions to PortManager. Also refactors ArchType into a separate class in common, since it is used now from several places. It is also expanded to handle future changes that add support for different processor architectures, e.g. aarch64.
2026-09-13 01:10:44 +03:00 · 2023-02-01 11:51:20 +01:00
parent 3194678007
commit ee4118c6bf
19 changed files with 696 additions and 228 deletions
@@ -20,6 +20,7 @@
 #include <map>

 #include "absl/strings/str_split.h"
+#include "common/arch_type.h"
 #include "common/log.h"
 #include "common/process.h"
 #include "common/remote_util.h"
@@ -30,6 +31,42 @@

 namespace cdc_ft {

+constexpr char kErrorArchTypeUnhandled[] = "arch_type_unhandled";
+
+// Returns the arch-specific netstat command.
+const char* GetNetstatCommand(ArchType arch_type) {
+  if (IsWindowsArchType(arch_type)) {
+    // -a to get the connection and ports the computer is listening on.
+    // -n to get numerical addresses to avoid the overhead of getting names.
+    // -p tcp to limit the output to TCPv4 connections.
+    return "netstat -a -n -p tcp";
+  }
+
+  if (IsLinuxArchType(arch_type)) {
+    // --numeric to get numerical addresses.
+    // --listening to get only listening sockets.
+    // --tcp to get only TCP connections.
+    return "netstat --numeric --listening --tcp";
+  }
+
+  assert(!kErrorArchTypeUnhandled);
+  return "";
+}
+
+// Returns the arch-specific IP address to filter netstat results by.
+const char* GetNetstatFilterIp(ArchType arch_type) {
+  if (IsWindowsArchType(arch_type)) {
+    return "127.0.0.1";
+  }
+
+  if (IsLinuxArchType(arch_type)) {
+    return "0.0.0.0";
+  }
+
+  assert(!kErrorArchTypeUnhandled);
+  return "";
+}
+
 class SharedMemory {
 public:
  // Creates a new shared memory instance with given |name| and |size| in bytes.
@@ -121,22 +158,25 @@ PortManager::~PortManager() {
  }
 }

-absl::StatusOr<int> PortManager::ReservePort(int remote_timeout_sec) {
+absl::StatusOr<int> PortManager::ReservePort(int remote_timeout_sec,
+                                             ArchType remote_arch_type) {
  // Find available port on workstation.
  std::unordered_set<int> local_ports;
-  ASSIGN_OR_RETURN(local_ports,
-                   FindAvailableLocalPorts(first_port_, last_port_, "127.0.0.1",
-                                           process_factory_),
-                   "Failed to find available ports on workstation");
+  ASSIGN_OR_RETURN(
+      local_ports,
+      FindAvailableLocalPorts(first_port_, last_port_,
+                              ArchType::kWindows_x86_64, process_factory_),
+      "Failed to find available ports on workstation");

  // Find available port on remote instance.
  std::unordered_set<int> remote_ports = local_ports;
  if (remote_util_ != nullptr) {
-    ASSIGN_OR_RETURN(remote_ports,
-                     FindAvailableRemotePorts(
-                         first_port_, last_port_, "0.0.0.0", process_factory_,
-                         remote_util_, remote_timeout_sec, steady_clock_),
-                     "Failed to find available ports on instance");
+    ASSIGN_OR_RETURN(
+        remote_ports,
+        FindAvailableRemotePorts(first_port_, last_port_, remote_arch_type,
+                                 process_factory_, remote_util_,
+                                 remote_timeout_sec, steady_clock_),
+        "Failed to find available ports on instance");
  }

  // Fetch shared memory.
@@ -203,14 +243,11 @@ absl::Status PortManager::ReleasePort(int port) {

 // static
 absl::StatusOr<std::unordered_set<int>> PortManager::FindAvailableLocalPorts(
-    int first_port, int last_port, const char* ip,
+    int first_port, int last_port, ArchType arch_type,
    ProcessFactory* process_factory) {
-  // -a to get the connection and ports the computer is listening on.
-  // -n to get numerical addresses to avoid the overhead of determining names.
-  // -p tcp to limit the output to TCPv4 connections.
-  // TODO: Use Windows API instead of netstat.
+  // TODO: Use local APIs instead of netstat.
  ProcessStartInfo start_info;
-  start_info.command = "netstat -a -n -p tcp";
+  start_info.command = GetNetstatCommand(arch_type);
  start_info.name = "netstat";
  start_info.flags = ProcessFlags::kNoWindow;

@@ -231,18 +268,15 @@ absl::StatusOr<std::unordered_set<int>> PortManager::FindAvailableLocalPorts(
  }

  LOG_DEBUG("netstat (workstation) output:\n%s", output);
-  return FindAvailablePorts(first_port, last_port, output, ip);
+  return FindAvailablePorts(first_port, last_port, output, arch_type);
 }

 // static
 absl::StatusOr<std::unordered_set<int>> PortManager::FindAvailableRemotePorts(
-    int first_port, int last_port, const char* ip,
+    int first_port, int last_port, ArchType arch_type,
    ProcessFactory* process_factory, RemoteUtil* remote_util, int timeout_sec,
    SteadyClock* steady_clock) {
-  // --numeric to get numerical addresses.
-  // --listening to get only listening sockets.
-  // --tcp to get only TCP connections.
-  std::string remote_command = "netstat --numeric --listening --tcp";
+  std::string remote_command = GetNetstatCommand(arch_type);
  ProcessStartInfo start_info =
      remote_util->BuildProcessStartInfoForSsh(remote_command);
  start_info.name = "netstat";
@@ -281,24 +315,25 @@ absl::StatusOr<std::unordered_set<int>> PortManager::FindAvailableRemotePorts(
  }

  LOG_DEBUG("netstat (instance) output:\n%s", output);
-  return FindAvailablePorts(first_port, last_port, output, ip);
+  return FindAvailablePorts(first_port, last_port, output, arch_type);
 }

 // static
 absl::StatusOr<std::unordered_set<int>> PortManager::FindAvailablePorts(
    int first_port, int last_port, const std::string& netstat_output,
-    const char* ip) {
+    ArchType arch_type) {
  std::unordered_set<int> available_ports;
  std::vector<std::string> lines;
+  const char* filter_ip = GetNetstatFilterIp(arch_type);
  for (const auto& line : absl::StrSplit(netstat_output, '\n')) {
-    if (absl::StrContains(line, ip)) {
+    if (absl::StrContains(line, filter_ip)) {
      lines.push_back(std::string(line));
    }
  }

  for (int port = first_port; port <= last_port; ++port) {
    bool port_occupied = false;
-    std::string portToken = absl::StrFormat("%s:%i", ip, port);
+    std::string portToken = absl::StrFormat("%s:%i", filter_ip, port);
    for (const std::string& line : lines) {
      // Ports in the TIME_WAIT state can be reused. It is common that ports
      // stay in this state for O(minutes).