1 files changed, 141 insertions, 0 deletions
diff --git a/src/download-via-ssh/download-via-ssh.cc b/src/download-via-ssh/download-via-ssh.cc
new file mode 100644
index 000000000000..b64455eb1724
--- /dev/null
+++ b/src/download-via-ssh/download-via-ssh.cc
@@ -0,0 +1,141 @@
+#include "shared.hh"
+#include "util.hh"
+#include "serialise.hh"
+#include "archive.hh"
+#include "affinity.hh"
+#include "globals.hh"
+#include "serve-protocol.hh"
+#include "worker-protocol.hh"
+#include "store-api.hh"
+
+#include <iostream>
+#include <unistd.h>
+
+using namespace nix;
+
+// !!! TODO:
+// * Respect more than the first host
+// * use a database
+// * show progress
+
+
+static std::pair<FdSink, FdSource> connect(const string & conn)
+{
+    Pipe to, from;
+    to.create();
+    from.create();
+    startProcess([&]() {
+        if (dup2(to.readSide, STDIN_FILENO) == -1)
+            throw SysError("dupping stdin");
+        if (dup2(from.writeSide, STDOUT_FILENO) == -1)
+            throw SysError("dupping stdout");
+        execlp("ssh", "ssh", "-x", "-T", conn.c_str(), "nix-store --serve", NULL);
+        throw SysError("executing ssh");
+    });
+    // If child exits unexpectedly, we'll EPIPE or EOF early.
+    // If we exit unexpectedly, child will EPIPE or EOF early.
+    // So no need to keep track of it.
+
+    return std::pair<FdSink, FdSource>(to.writeSide.borrow(), from.readSide.borrow());
+}
+
+
+static void substitute(std::pair<FdSink, FdSource> & pipes, Path storePath, Path destPath)
+{
+    writeInt(cmdDumpStorePath, pipes.first);
+    writeString(storePath, pipes.first);
+    pipes.first.flush();
+    restorePath(destPath, pipes.second);
+    std::cout << std::endl;
+}
+
+
+static void query(std::pair<FdSink, FdSource> & pipes)
+{
+    for (string line; getline(std::cin, line);) {
+        Strings tokenized = tokenizeString<Strings>(line);
+        string cmd = tokenized.front();
+        tokenized.pop_front();
+        if (cmd == "have") {
+            writeInt(cmdQueryValidPaths, pipes.first);
+            writeInt(0, pipes.first); // don't lock
+            writeInt(0, pipes.first); // don't substitute
+            writeStrings(tokenized, pipes.first);
+            pipes.first.flush();
+            PathSet paths = readStrings<PathSet>(pipes.second);
+            foreach (PathSet::iterator, i, paths)
+                std::cout << *i << std::endl;
+        } else if (cmd == "info") {
+            writeInt(cmdQueryPathInfos, pipes.first);
+            writeStrings(tokenized, pipes.first);
+            pipes.first.flush();
+            while (1) {
+                Path path = readString(pipes.second);
+                if (path.empty()) break;
+                assertStorePath(path);
+                std::cout << path << std::endl;
+                string deriver = readString(pipes.second);
+                if (!deriver.empty()) assertStorePath(deriver);
+                std::cout << deriver << std::endl;
+                PathSet references = readStorePaths<PathSet>(pipes.second);
+                std::cout << references.size() << std::endl;
+                foreach (PathSet::iterator, i, references)
+                    std::cout << *i << std::endl;
+                std::cout << readLongLong(pipes.second) << std::endl;
+                std::cout << readLongLong(pipes.second) << std::endl;
+            }
+        } else
+            throw Error(format("unknown substituter query ‘%1%’") % cmd);
+        std::cout << std::endl;
+    }
+}
+
+
+int main(int argc, char * * argv)
+{
+    return handleExceptions(argv[0], [&]() {
+        if (argc < 2)
+            throw UsageError("download-via-ssh requires an argument");
+
+        initNix();
+
+        settings.update();
+
+        if (settings.sshSubstituterHosts.empty())
+            return;
+
+        std::cout << std::endl;
+
+        /* Pass on the location of the daemon client's SSH
+           authentication socket. */
+        string sshAuthSock = settings.get("ssh-auth-sock", string(""));
+        if (sshAuthSock != "") setenv("SSH_AUTH_SOCK", sshAuthSock.c_str(), 1);
+
+        string host = settings.sshSubstituterHosts.front();
+        std::pair<FdSink, FdSource> pipes = connect(host);
+
+        /* Exchange the greeting */
+        writeInt(SERVE_MAGIC_1, pipes.first);
+        pipes.first.flush();
+        unsigned int magic = readInt(pipes.second);
+        if (magic != SERVE_MAGIC_2)
+            throw Error("protocol mismatch");
+        readInt(pipes.second); // Server version, unused for now
+        writeInt(SERVE_PROTOCOL_VERSION, pipes.first);
+        pipes.first.flush();
+
+        string arg = argv[1];
+        if (arg == "--query")
+            query(pipes);
+        else if (arg == "--substitute") {
+            if (argc != 4)
+                throw UsageError("download-via-ssh: --substitute takes exactly two arguments");
+            Path storePath = argv[2];
+            Path destPath = argv[3];
+            printMsg(lvlError, format("downloading ‘%1%’ via SSH from ‘%2%’...") % storePath % host);
+            substitute(pipes, storePath, destPath);
+        }
+        else
+            throw UsageError(format("download-via-ssh: unknown command ‘%1%’") % arg);
+    });
+}