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#include "ssh.hh"
namespace nix {
std::unique_ptr<SSHMaster::Connection> SSHMaster::startCommand(const std::string & command)
{
startMaster();
Pipe in, out;
in.create();
out.create();
auto conn = std::make_unique<Connection>();
conn->sshPid = startProcess([&]() {
restoreSignals();
close(in.writeSide.get());
close(out.readSide.get());
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");
Strings args = { "ssh", host.c_str(), "-x", "-a" };
if (!keyFile.empty())
args.insert(args.end(), {"-i", keyFile});
if (compress)
args.push_back("-C");
if (useMaster)
args.insert(args.end(), {"-S", socketPath});
args.push_back(command);
execvp(args.begin()->c_str(), stringsToCharPtrs(args).data());
throw SysError("executing ‘%s’ on ‘%s’", command, host);
});
in.readSide = -1;
out.writeSide = -1;
conn->out = std::move(out.readSide);
conn->in = std::move(in.writeSide);
return conn;
}
void SSHMaster::startMaster()
{
if (!useMaster || sshMaster != -1) return;
tmpDir = std::make_unique<AutoDelete>(createTempDir("", "nix", true, true, 0700));
socketPath = (Path) *tmpDir + "/ssh.sock";
Pipe out;
out.create();
sshMaster = startProcess([&]() {
restoreSignals();
close(out.readSide.get());
if (dup2(out.writeSide.get(), STDOUT_FILENO) == -1)
throw SysError("duping over stdout");
Strings args =
{ "ssh", host.c_str(), "-M", "-N", "-S", socketPath
, "-o", "LocalCommand=echo started"
, "-o", "PermitLocalCommand=yes"
};
if (!keyFile.empty())
args.insert(args.end(), {"-i", keyFile});
if (compress)
args.push_back("-C");
execvp(args.begin()->c_str(), stringsToCharPtrs(args).data());
throw SysError("starting SSH master");
});
out.writeSide = -1;
std::string reply;
try {
reply = readLine(out.readSide.get());
} catch (EndOfFile & e) { }
if (reply != "started")
throw Error("failed to start SSH master connection to ‘%s’", host);
}
}
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