1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
|
#include "ssh.hh"
namespace nix {
SSHMaster::SSHMaster(const std::string & host, const std::string & keyFile, bool useMaster, bool compress, int logFD)
: host(host)
, fakeSSH(host == "localhost")
, keyFile(keyFile)
, useMaster(useMaster && !fakeSSH)
, compress(compress)
, logFD(logFD)
{
if (host == "" || hasPrefix(host, "-"))
throw Error("invalid SSH host name '%s'", host);
}
void SSHMaster::addCommonSSHOpts(Strings & args)
{
for (auto & i : tokenizeString<Strings>(getEnv("NIX_SSHOPTS")))
args.push_back(i);
if (!keyFile.empty())
args.insert(args.end(), {"-i", keyFile});
if (compress)
args.push_back("-C");
}
std::unique_ptr<SSHMaster::Connection> SSHMaster::startCommand(const std::string & command)
{
Path socketPath = 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");
if (logFD != -1 && dup2(logFD, STDERR_FILENO) == -1)
throw SysError("duping over stderr");
Strings args;
const char * execInto;
if (fakeSSH) {
execInto = "bash";
args = { "bash", "-c" };
} else {
execInto = "ssh";
args = { "ssh", host.c_str(), "-x", "-a" };
addCommonSSHOpts(args);
if (socketPath != "")
args.insert(args.end(), {"-S", socketPath});
if (verbosity >= lvlChatty)
args.push_back("-v");
}
args.push_back(command);
execvp(args.begin()->c_str(), stringsToCharPtrs(args).data());
// could not exec ssh/bash
throw SysError("Failed to exec into %s. Is it in PATH?", execInto);
});
in.readSide = -1;
out.writeSide = -1;
conn->out = std::move(out.readSide);
conn->in = std::move(in.writeSide);
return conn;
}
Path SSHMaster::startMaster()
{
if (!useMaster) return "";
auto state(state_.lock());
if (state->sshMaster != -1) return state->socketPath;
state->tmpDir = std::make_unique<AutoDelete>(createTempDir("", "nix", true, true, 0700));
state->socketPath = (Path) *state->tmpDir + "/ssh.sock";
Pipe out;
out.create();
state->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", state->socketPath
, "-o", "LocalCommand=echo started"
, "-o", "PermitLocalCommand=yes"
};
if (verbosity >= lvlChatty)
args.push_back("-v");
addCommonSSHOpts(args);
execvp(args.begin()->c_str(), stringsToCharPtrs(args).data());
throw SysError("Failed to exec into ssh. Is it in PATH?");
});
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);
return state->socketPath;
}
}
|
