1 files changed, 56 insertions, 47 deletions

diff --git a/src/libstore/legacy-ssh-store.cc b/src/libstore/legacy-ssh-store.cc
index b20ff185f9ba..befc560bfcec 100644
--- a/src/libstore/legacy-ssh-store.cc
+++ b/src/libstore/legacy-ssh-store.cc
@@ -4,80 +4,54 @@
 #include "serve-protocol.hh"
 #include "store-api.hh"
 #include "worker-protocol.hh"
+#include "ssh.hh"
 
 namespace nix {
 
-static std::string uriScheme = "legacy-ssh://";
+static std::string uriScheme = "ssh://";
 
 struct LegacySSHStore : public Store
 {
-    string host;
+    const Setting<int> maxConnections{this, 1, "max-connections", "maximum number of concurrent SSH connections"};
+    const Setting<Path> sshKey{this, "", "ssh-key", "path to an SSH private key"};
+    const Setting<bool> compress{this, false, "compress", "whether to compress the connection"};
 
     struct Connection
     {
-        Pid sshPid;
-        AutoCloseFD out;
-        AutoCloseFD in;
+        std::unique_ptr<SSHMaster::Connection> sshConn;
         FdSink to;
         FdSource from;
     };
 
-    AutoDelete tmpDir;
-
-    Path socketPath;
-
-    Pid sshMaster;
+    std::string host;
 
     ref<Pool<Connection>> connections;
 
-    Path key;
+    SSHMaster master;
 
-    LegacySSHStore(const string & host, const Params & params,
-        size_t maxConnections = std::numeric_limits<size_t>::max())
+    LegacySSHStore(const string & host, const Params & params)
         : Store(params)
         , host(host)
-        , tmpDir(createTempDir("", "nix", true, true, 0700))
-        , socketPath((Path) tmpDir + "/ssh.sock")
         , connections(make_ref<Pool<Connection>>(
-            maxConnections,
+            std::max(1, (int) maxConnections),
             [this]() { return openConnection(); },
             [](const ref<Connection> & r) { return true; }
             ))
-        , key(get(params, "ssh-key", ""))
+        , master(
+            host,
+            sshKey,
+            // Use SSH master only if using more than 1 connection.
+            connections->capacity() > 1,
+            compress)
     {
     }
 
     ref<Connection> openConnection()
     {
-        if ((pid_t) sshMaster == -1) {
-            sshMaster = startProcess([&]() {
-                restoreSignals();
-                Strings args{ "ssh", "-M", "-S", socketPath, "-N", "-x", "-a", host };
-                if (!key.empty())
-                    args.insert(args.end(), {"-i", key});
-                execvp("ssh", stringsToCharPtrs(args).data());
-                throw SysError("starting SSH master connection to host ‘%s’", host);
-            });
-        }
-
         auto conn = make_ref<Connection>();
-        Pipe in, out;
-        in.create();
-        out.create();
-        conn->sshPid = startProcess([&]() {
-            if (dup2(in.readSide.get(), STDIN_FILENO) == -1)
-                throw SysError("duping over STDIN");
-            if (dup2(out.writeSide.get(), STDOUT_FILENO) == -1)
-                throw SysError("duping over STDOUT");
-            execlp("ssh", "ssh", "-S", socketPath.c_str(), host.c_str(), "nix-store", "--serve", "--write", nullptr);
-            throw SysError("executing ‘nix-store --serve’ on remote host ‘%s’", host);
-        });
-        in.readSide = -1;
-        out.writeSide = -1;
-        conn->out = std::move(out.readSide);
-        conn->in = std::move(in.writeSide);
-        conn->to = FdSink(conn->in.get());
-        conn->from = FdSource(conn->out.get());
+        conn->sshConn = master.startCommand("nix-store --serve --write");
+        conn->to = FdSink(conn->sshConn->in.get());
+        conn->from = FdSource(conn->sshConn->out.get());
 
         int remoteVersion;
 
@@ -169,9 +143,9 @@ struct LegacySSHStore : public Store
 
         /* FIXME: inefficient. */
         ParseSink parseSink; /* null sink; just parse the NAR */
-        SavingSourceAdapter savedNAR(conn->from);
+        TeeSource savedNAR(conn->from);
         parseDump(parseSink, savedNAR);
-        sink(savedNAR.s);
+        sink(*savedNAR.data);
     }
 
     /* Unsupported methods. */
@@ -234,6 +208,41 @@ struct LegacySSHStore : public Store
     bool isTrusted() override
     { return true; }
 
+    void computeFSClosure(const PathSet & paths,
+        PathSet & out, bool flipDirection = false,
+        bool includeOutputs = false, bool includeDerivers = false) override
+    {
+        if (flipDirection || includeDerivers) {
+            Store::computeFSClosure(paths, out, flipDirection, includeOutputs, includeDerivers);
+            return;
+        }
+
+        auto conn(connections->get());
+
+        conn->to
+            << cmdQueryClosure
+            << includeOutputs
+            << paths;
+        conn->to.flush();
+
+        auto res = readStorePaths<PathSet>(*this, conn->from);
+
+        out.insert(res.begin(), res.end());
+    }
+
+    PathSet queryValidPaths(const PathSet & paths, bool maybeSubstitute = false) override
+    {
+        auto conn(connections->get());
+
+        conn->to
+            << cmdQueryValidPaths
+            << false // lock
+            << maybeSubstitute
+            << paths;
+        conn->to.flush();
+
+        return readStorePaths<PathSet>(*this, conn->from);
+    }
 };
 
 static RegisterStoreImplementation regStore([](