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remote.cxx
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remote.cxx
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// systemtap remote execution
// Copyright (C) 2010-2015 Red Hat Inc.
//
// This file is part of systemtap, and is free software. You can
// redistribute it and/or modify it under the terms of the GNU General
// Public License (GPL); either version 2, or (at your option) any
// later version.
#include "config.h"
extern "C" {
#include <fcntl.h>
#include <poll.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <json-c/json.h>
}
#include <cstdio>
#include <iomanip>
#include <memory>
#include <stdexcept>
#include <sstream>
#include <string>
#include <vector>
#include "buildrun.h"
#include "remote.h"
#include "util.h"
using namespace std;
struct pod {
string name;
string node;
vector <string> containers;
};
struct container {
string name;
pod hostpod;
};
// Decode URIs as per RFC 3986, though not bothering to be strict
class uri_decoder {
public:
const string uri;
string scheme, authority, path, query, fragment;
bool has_authority, has_query, has_fragment;
uri_decoder(const string& uri):
uri(uri), has_authority(false), has_query(false), has_fragment(false)
{
const string re =
"^([^:]+):(//[^/?#]*)?([^?#]*)(\\?[^#]*)?(#.*)?$";
vector<string> matches;
if (regexp_match(uri, re, matches) != 0)
throw runtime_error(_F("string doesn't appear to be a URI: %s", uri.c_str()));
scheme = matches[1];
if (!matches[2].empty())
{
has_authority = true;
authority = matches[2].substr(2);
}
path = matches[3];
if (!matches[4].empty())
{
has_query = true;
query = matches[4].substr(1);
}
if (!matches[5].empty())
{
has_fragment = true;
fragment = matches[5].substr(1);
}
}
};
// loopback target for running locally
class direct : public remote {
private:
pid_t child;
vector<string> args;
direct(systemtap_session& s): remote(s), child(0) {}
int start()
{
args = make_run_command(*s);
if (! staprun_r_arg.empty()) // PR13354
{
if (s->runtime_mode == systemtap_session::dyninst_runtime)
args.insert(args.end(), {"_stp_dyninst_remote=" + staprun_r_arg});
else
args.insert(args.end(), { "-r", staprun_r_arg });
}
pid_t pid = stap_spawn (s->verbose, args);
if (pid <= 0)
return 1;
child = pid;
return 0;
}
int finish()
{
if (child <= 0)
return 1;
int ret = stap_waitpid(s->verbose, child);
if (ret > 128)
s->print_warning(_F("%s exited with signal: %d (%s)",
args.front().c_str(), ret - 128,
strsignal(ret - 128)));
else if (ret > 0)
s->print_warning(_F("%s exited with status: %d",
args.front().c_str(), ret));
child = 0;
return ret;
}
public:
friend class remote;
virtual ~direct() { finish(); }
};
class stapsh : public remote {
private:
int interrupts_sent;
int fdin, fdout;
FILE *IN, *OUT;
string remote_version;
size_t data_size;
string target_stream;
enum {
STAPSH_READY, // ready to receive next command
STAPSH_DATA // currently printing data from a 'data' command
} stream_state;
virtual void prepare_poll(vector<pollfd>& fds)
{
if (fdout >= 0 && OUT)
{
pollfd p = { fdout, POLLIN, 0 };
fds.push_back(p);
}
// need to send a signal?
if (fdin >= 0 && IN && interrupts_sent < pending_interrupts)
{
pollfd p = { fdin, POLLOUT, 0 };
fds.push_back(p);
}
}
virtual void handle_poll(vector<pollfd>& fds)
{
for (unsigned i=0; i < fds.size(); ++i)
if (fds[i].fd == fdin || fds[i].fd == fdout)
{
bool err = false;
// need to send a signal?
if (fds[i].revents & POLLOUT && IN &&
interrupts_sent < pending_interrupts)
{
if (send_command("quit\n") == 0)
++interrupts_sent;
else
err = true;
}
// have data to read?
if (fds[i].revents & POLLIN && OUT)
{
// if stapsh doesn't support commands, then just dump everything
if (!vector_has(options, string("data")))
{
// NB: we could splice here, but we don't know how much
// data is available for reading. One way could be to
// splice in small chunks and poll() fdout to check if
// there's more.
char buf[4096];
size_t bytes_read;
while ((bytes_read = fread(buf, 1, sizeof(buf), OUT)) > 0)
printout(buf, bytes_read);
if (errno != EAGAIN)
err = true;
}
else // we expect commands (just data for now)
{
// When the 'data' option is turned on, all outputs from
// staprun are first prepended with a line formatted as
// "data <stream> <size>\n", where <stream> is either
// "stdout" or "stderr", and <size> is the size of the
// data. Also, the line "quit\n" is sent from stapsh right
// before it exits.
if (stream_state == STAPSH_READY)
{
char cmdbuf[1024];
char *rc;
while ((rc = fgets(cmdbuf, sizeof(cmdbuf), OUT)) != NULL)
{
// check if it's a debug output from stapsh itself
string line = string(cmdbuf);
if (startswith(line, "stapsh:"))
clog << line;
else if (startswith(line, "quit\n"))
// && vector_has(options, string("data")))
// uncomment above if another command becomes
// possible
{
err = true; // close connection
break;
}
else if (startswith(line, "data"))
// && vector_has(options, string("data")))
// uncomment above if another command becomes
// possible
{
vector<string> cmd;
tokenize(line, cmd, " \t\r\n");
if (!is_valid_data_cmd(cmd))
{
clog << _("invalid data command from stapsh") << endl;
clog << _("received: ") << line;
err = true;
}
else
{
target_stream = cmd[1];
data_size = lex_cast<size_t>(cmd[2]);
stream_state = STAPSH_DATA;
}
break;
}
}
if (rc == NULL && errno != EAGAIN)
err = true;
}
if (stream_state == STAPSH_DATA)
{
if (data_size != 0)
{
// keep reading from OUT until either dry or data_size bytes done
char buf[4096];
size_t max_read = min<size_t>(sizeof(buf), data_size);
size_t bytes_read = 0;
while (max_read > 0
&& (bytes_read = fread(buf, 1, max_read, OUT)) > 0)
{
printout(buf, bytes_read);
data_size -= bytes_read;
max_read = min<size_t>(sizeof(buf), data_size);
}
if (bytes_read == 0 && errno != EAGAIN)
err = true;
}
if (data_size == 0)
stream_state = STAPSH_READY;
}
}
}
// any errors?
if (err || fds[i].revents & ~(POLLIN|POLLOUT))
close();
}
}
string get_reply()
{
// Some schemes like unix may have stdout and stderr mushed together.
// There shouldn't be anything except dbug messages on stderr before we
// actually start running, and there's no get_reply after that. So
// we'll just loop and skip those that start with "stapsh:".
char reply[4096];
while (fgets(reply, sizeof(reply), OUT))
{
if (!startswith(reply, "stapsh:"))
return reply;
// if data is not prefixed, we will have no way to distinguish
// between stdout and stderr during staprun runtime, so we might as
// well print to stdout now as well to be more consistent
if (vector_has(options, string("data")))
clog << reply; // must be stderr since only replies go to stdout
else
cout << reply; // output to stdout to be more consistent with later
}
// Reached EOF, nothing to reply...
return "";
}
int send_command(const string& cmd)
{
if (!IN)
return 2;
if (fputs(cmd.c_str(), IN) < 0 ||
fflush(IN) != 0)
return 1;
return 0;
}
int send_file(const string& filename, const string& dest)
{
int rc = 0;
FILE* f = fopen(filename.c_str(), "r");
if (!f)
return 1;
struct stat fs;
rc = fstat(fileno(f), &fs);
if (!rc)
{
ostringstream cmd;
cmd << "file " << fs.st_size << " " << dest << "\n";
rc = send_command(cmd.str());
}
off_t i = 0;
while (!rc && i < fs.st_size)
{
char buf[4096];
size_t r = sizeof(buf);
if (fs.st_size - i < (off_t)r)
r = fs.st_size - i;
r = fread(buf, 1, r, f);
if (r == 0)
rc = 1;
else
{
size_t w = fwrite(buf, 1, r, IN);
if (w != r)
rc = 1;
else
i += w;
}
}
if (!rc)
rc = fflush(IN);
fclose(f);
if (!rc)
{
string reply = get_reply();
if (reply != "OK\n")
{
rc = 1;
if (s->verbose > 0)
{
if (reply.empty())
clog << _("stapsh file ERROR: no reply") << endl;
else
clog << _F("stapsh file replied %s", reply.c_str());
}
}
}
return rc;
}
static string qpencode(const string& str)
{
ostringstream o;
o << setfill('0') << hex;
for (const char* s = str.c_str(); *s; ++s)
if (*s >= 33 && *s <= 126 && *s != 61)
o << *s;
else
o << '=' << setw(2) << (unsigned)(unsigned char) *s;
return o.str();
}
static bool is_valid_data_cmd(const vector<string>& cmd)
{
bool err = false;
err = err || (cmd[0] != "data");
err = err || (cmd[1] != "stdout" && cmd[1] != "stderr");
if (!err) // try to cast as size_t
try { lex_cast<size_t>(cmd[2]); }
catch (...) { err = true; }
return !err;
}
virtual void printout(const char *buf, size_t size)
{
static string last_prefix;
static bool on_same_line;
if (size == 0)
return;
// don't prefix for stderr to be more consistent with ssh
if (!prefix.empty() && target_stream != "stderr")
{
vector<pair<const char*,int> > lines = split_lines(buf, size);
for (vector<pair<const char*,int> >::iterator it = lines.begin();
it != lines.end(); ++it)
{
if (last_prefix != prefix)
{
if (on_same_line)
cout << endl;
cout << prefix;
}
else if (!on_same_line)
cout << prefix;
cout.write(it->first, it->second);
}
cout.flush();
const char *last_line = lines.back().first;
const char last_char = last_line[lines.back().second-1];
on_same_line = !lines.empty() && last_char != '\n';
last_prefix = prefix;
}
else
{
// Otherwise dump the whole block
// NB: The buf could contain binary data,
// including \0, so write as a block instead of
// the usual << string.
if (target_stream == "stdout")
{
cout.write(buf, size);
cout.flush();
}
else // stderr
clog.write(buf, size);
}
}
protected:
stapsh(systemtap_session& s)
: remote(s), interrupts_sent(0),
fdin(-1), fdout(-1), IN(0), OUT(0),
data_size(0), target_stream("stdout"), // default to stdout for schemes
stream_state(STAPSH_READY) // that don't pipe stderr (e.g. ssh)
{}
vector<string> options;
virtual int prepare()
{
int rc = 0;
string extension = s->runtime_mode == systemtap_session::dyninst_runtime ? ".so" : ".ko";
string localmodule = s->tmpdir + "/" + s->module_name + extension;
string remotemodule = s->module_name + extension;
if ((rc = send_file(localmodule, remotemodule)))
return rc;
if (file_exists(localmodule + ".sgn") &&
(rc = send_file(localmodule + ".sgn", remotemodule + ".sgn")))
return rc;
if (!s->uprobes_path.empty())
{
string remoteuprobes = basename(s->uprobes_path.c_str());
if ((rc = send_file(s->uprobes_path, remoteuprobes)))
return rc;
if (file_exists(s->uprobes_path + ".sgn") &&
(rc = send_file(s->uprobes_path + ".sgn", remoteuprobes + ".sgn")))
return rc;
}
return rc;
}
virtual int start()
{
// Send the staprun args
// NB: The remote is left to decide its own staprun path
ostringstream run("run", ios::out | ios::ate);
vector<string> cmd = make_run_command(*s, ".", remote_version);
// PR13354: identify our remote index/url
if (strverscmp("1.7", remote_version.c_str()) <= 0 && // -r supported?
! staprun_r_arg.empty())
{
if (s->runtime_mode == systemtap_session::dyninst_runtime)
cmd.insert(cmd.end(), { "_stp_dyninst_remote=" + staprun_r_arg});
else
cmd.insert(cmd.end(), { "-r", staprun_r_arg });
}
for (unsigned i = 1; i < cmd.size(); ++i)
run << ' ' << qpencode(cmd[i]);
run << '\n';
int rc = send_command(run.str());
if (!rc)
{
string reply = get_reply();
if (reply != "OK\n")
{
rc = 1;
if (s->verbose > 0)
{
if (reply.empty())
clog << _("stapsh run ERROR: no reply") << endl;
else
clog << _F("stapsh run replied %s", reply.c_str());
}
}
}
if (!rc)
{
long flags;
if ((flags = fcntl(fdout, F_GETFL)) == -1
|| fcntl(fdout, F_SETFL, flags | O_NONBLOCK) == -1)
{
clog << _("failed to change to non-blocking mode") << endl;
rc = 1;
}
}
if (rc)
// If run failed for any reason, then this
// connection is effectively dead to us.
close();
return rc;
}
void close()
{
if (IN) fclose(IN);
if (OUT) fclose(OUT);
IN = OUT = NULL;
fdin = fdout = -1;
}
virtual int finish()
{
close();
return 0;
}
void set_child_fds(int in, int out)
{
if (fdin >= 0 || fdout >= 0 || IN || OUT)
throw runtime_error(_("stapsh file descriptors already set"));
fdin = in;
fdout = out;
IN = fdopen(fdin, "w");
OUT = fdopen(fdout, "r");
if (!IN || !OUT)
throw runtime_error(_("invalid file descriptors for stapsh"));
if (send_command("stap " VERSION "\n"))
throw runtime_error(_("error sending hello to stapsh"));
string reply = get_reply();
if (reply.empty())
throw runtime_error(_("error receiving hello from stapsh"));
// stapsh VERSION MACHINE RELEASE
vector<string> uname;
tokenize(reply, uname, " \t\r\n");
if (uname.size() != 4 || uname[0] != "stapsh")
throw runtime_error(_F("invalid hello from stapsh: %s", reply.c_str()));
// We assume that later versions will know how to talk to us.
// Looking backward, we use this for make_run_command().
this->remote_version = uname[1];
this->s = s->clone(uname[2], uname[3]);
// set any option requested
if (!this->options.empty())
{
// check first if the option command is supported
if (strverscmp("2.4", this->remote_version.c_str()) > 0)
throw runtime_error(_F("stapsh %s does not support options",
this->remote_version.c_str()));
for (vector<string>::iterator it = this->options.begin();
it != this->options.end(); ++it)
{
int rc = send_command("option " + *it + "\n");
if (rc != 0)
throw runtime_error(_F("could not set option %s: "
"send_command returned %d",
it->c_str(), rc));
string reply = get_reply();
if (reply != "OK\n")
throw runtime_error(_F("could not set option %s: %s",
it->c_str(), reply.c_str()));
}
}
}
public:
virtual ~stapsh() { close(); }
};
// direct_stapsh is meant only for testing, as a way to exercise the stapsh
// mechanisms without requiring test machines to have actual remote access.
class direct_stapsh : public stapsh {
private:
pid_t child;
direct_stapsh(systemtap_session& s)
: stapsh(s), child(0)
{
int in, out;
vector<string> cmd { BINDIR "/stapsh" };
if (s.perpass_verbose[4] > 1)
cmd.push_back("-v");
if (s.perpass_verbose[4] > 2)
cmd.push_back("-v");
// mask signals while we spawn, so we can simulate manual signals to
// the "remote" target, as we must for the real ssh_remote case.
{
stap_sigmasker masked;
child = stap_spawn_piped(s.verbose, cmd, &in, &out);
}
if (child <= 0)
throw runtime_error(_("error launching stapsh"));
try
{
set_child_fds(in, out);
}
catch (runtime_error&)
{
finish();
throw;
}
}
virtual int finish()
{
int rc = stapsh::finish();
if (child <= 0)
return rc;
int rc2 = stap_waitpid(s->verbose, child);
child = 0;
return rc ?: rc2;
}
public:
friend class remote;
virtual ~direct_stapsh() { finish(); }
};
// Connect to an existing stapsh on a unix socket.
class unix_stapsh : public stapsh {
private:
unix_stapsh(systemtap_session& s, const uri_decoder& ud)
: stapsh(s)
{
// Request that data be encapsulated since both stdout and stderr have
// to go over the same line. Also makes stapsh tell us when it quits.
this->options.push_back("data");
// set verbosity to the requested level
for (unsigned i = 1; i < s.perpass_verbose[4]; i++)
this->options.push_back("verbose");
sockaddr_un server;
server.sun_family = AF_UNIX;
if (ud.path.empty())
throw runtime_error(_("unix target requires a /path"));
if (ud.path.size() > sizeof(server.sun_path) - 1)
throw runtime_error(_("unix target /path is too long"));
strcpy(server.sun_path, ud.path.c_str());
if (ud.has_authority)
throw runtime_error(_("unix target doesn't support a hostname"));
if (ud.has_query)
throw runtime_error(_("unix target URI doesn't support a ?query"));
if (ud.has_fragment)
throw runtime_error(_("unix target URI doesn't support a #fragment"));
int fd = socket(AF_UNIX, SOCK_STREAM, 0);
if (fd <= 0)
throw runtime_error(_("error opening a socket"));
if (connect(fd, (struct sockaddr *)&server, SUN_LEN(&server)) < 0)
{
const char *msg = strerror(errno);
::close(fd);
throw runtime_error(_F("error connecting to socket %s: %s",
server.sun_path, msg));
}
// Try to dup it, so class stapsh can have truly separate fds for its
// fdopen handles. If it fails for some reason, it can still work with
// just one though.
int fd2 = dup(fd);
if (fd2 < 0)
fd2 = fd;
try
{
set_child_fds(fd, fd2);
}
catch (runtime_error&)
{
finish();
::close(fd);
::close(fd2);
throw;
}
}
public:
friend class remote;
virtual ~unix_stapsh() { finish(); }
};
class libvirt_stapsh : public stapsh {
private:
pid_t child;
libvirt_stapsh(systemtap_session& s, const uri_decoder& ud)
: stapsh(s)
{
string domain;
string libvirt_uri;
// Request that data be encapsulated since both stdout and stderr have
// to go over the same line. Also makes stapsh tell us when it quits.
this->options.push_back("data");
// set verbosity to the requested level
for (unsigned i = 1; i < s.perpass_verbose[4]; i++)
this->options.push_back("verbose");
// A valid libvirt URI has one of two forms:
// - libvirt://DOMAIN/LIBVIRT_URI?LIBVIRT_QUERY
// - libvirt:DOMAIN/LIBVIRT_URI?LIBVIRT_QUERY
// We only advertise the first form, but to be nice, we also accept the
// second form. In the first form, DOMAIN is authority, LIBVIRT_URI is
// path, and LIBVIRT_QUERY is the query. In the second form, the DOMAIN
// is part of the path.
if (ud.has_fragment)
throw runtime_error(_("libvirt target URI doesn't support a #fragment"));
if (ud.has_authority) // first form
{
domain = ud.authority;
if (!ud.path.empty())
{
libvirt_uri = ud.path.substr(1);
if (ud.has_query)
libvirt_uri += "?" + ud.query;
}
}
else // second form
{
if (ud.path.empty())
throw runtime_error(_("libvirt target URI requires a domain name"));
size_t slash = ud.path.find_first_of('/');
if (slash == string::npos)
domain = ud.path;
else
{
domain = ud.path.substr(0, slash);
libvirt_uri = ud.path.substr(slash+1);
}
}
int in, out;
string stapvirt = BINDIR "/stapvirt";
if (!file_exists(stapvirt))
throw runtime_error(_("stapvirt missing"));
vector<string> cmd { stapvirt };
// carry verbosity into stapvirt
if (s.perpass_verbose[4] > 0)
cmd.insert(cmd.end(), s.perpass_verbose[4] - 1, "-v");
if (!libvirt_uri.empty())
cmd.insert(cmd.end(), { "-c", libvirt_uri });
cmd.insert(cmd.end(), { "connect", domain });
// mask signals for stapvirt since it relies instead on stap or stapsh
// closing its connection to know when to exit (otherwise, stapvirt
// would receive SIGINT on Ctrl-C and exit nonzero)
// NB: There is an interesting issue to note here. Some libvirt URIs
// will create child processes of stapvirt (e.g. qemu+ssh:// will
// create an ssh process under stapvirt, also qemu+ext://, see
// <libvirt.org/remote.html> for more info). These processes do not
// keep the mask of stapvirt we are creating here, but are still part
// of the same process group.
// This means that e.g. SIGINT will not be blocked. Thus, stapvirt
// explicitly adds a handler for SIGCHLD and forcefully disconnects
// upon receiving it (otherwise it would await indefinitely).
{
stap_sigmasker masked;
child = stap_spawn_piped(s.verbose, cmd, &in, &out);
}
if (child <= 0)
throw runtime_error(_("error launching stapvirt"));
try
{
set_child_fds(in, out);
}
catch (runtime_error&)
{
finish();
throw;
}
}
int finish()
{
int rc = stapsh::finish();
if (child <= 0)
return rc;
int rc2 = stap_waitpid(s->verbose, child);
child = 0;
return rc ?: rc2;
}
public:
friend class remote;
virtual ~libvirt_stapsh() { finish(); }
};
// stapsh-based ssh_remote
class ssh_remote : public stapsh {
private:
pid_t child;
ssh_remote(systemtap_session& s): stapsh(s), child(0) {}
int connect(const string& host, const string& port)
{
int rc = 0;
int in, out;
vector<string> cmd { "ssh", "-q", host };
if (!port.empty())
cmd.insert(cmd.end(), { "-p", port });
// This is crafted so that we get a silent failure with status 127 if
// the command is not found. The combination of -P and $cmd ensures
// that we pull the command out of the PATH, not aliases or such.
string stapsh_cmd = "cmd=`type -P stapsh || exit 127` && exec \"$cmd\"";
if (s->perpass_verbose[4] > 1)
stapsh_cmd.append(" -v");
if (s->perpass_verbose[4] > 2)
stapsh_cmd.append(" -v");
// NB: We need to explicitly choose bash, as $SHELL may be weird...
cmd.push_back("/bin/bash -c '" + stapsh_cmd + "'");
// mask signals while we spawn, so we can manually send even tty
// signals *through* ssh rather than to ssh itself
{
stap_sigmasker masked;
child = stap_spawn_piped(s->verbose, cmd, &in, &out);
}
if (child <= 0)
throw runtime_error(_("error launching stapsh"));
try
{
set_child_fds(in, out);
}
catch (runtime_error&)
{
rc = finish();
// ssh itself signals errors with 255
if (rc == 255)
throw runtime_error(_("error establishing ssh connection"));
// If rc == 127, that's command-not-found, so we let ::create()
// try again in legacy mode. But only do this if there's a single
// remote, as the old code didn't handle ttys well with multiple
// remotes. Otherwise, throw up again. *barf*
if (rc != 127 || s->remote_uris.size() > 1)
throw;
}
return rc;
}
int finish()
{
int rc = stapsh::finish();
if (child <= 0)
return rc;
int rc2 = stap_waitpid(s->verbose, child);
child = 0;
return rc ?: rc2;
}
public:
static remote* create(systemtap_session& s, const string& host);
static remote* create(systemtap_session& s, const uri_decoder& ud);
virtual ~ssh_remote() { finish(); }
};
// ssh connection without stapsh, for legacy stap installations
// NB: ssh commands use a tty (-t) so signals are passed along to the remote.
// It does this by putting the local tty in raw mode, so it only works for tty
// signals, and only for a single remote at a time.
class ssh_legacy_remote : public remote {
private:
vector<string> ssh_args, scp_args;
string ssh_control;
string host, port, tmpdir;
pid_t child;
ssh_legacy_remote(systemtap_session& s, const string& host, const string& port)
: remote(s), host(host), port(port), child(0)
{
open_control_master();
try
{
get_uname();
}
catch (runtime_error&)
{
close_control_master();
throw;
}
}
vector<string> ssh_command(initializer_list<string> ilist)
{
vector<string> cmd = ssh_args;
cmd.insert(cmd.end(), ilist);
return cmd;
}
int copy_to_remote(const string& local, const string& remote)
{
vector<string> cmd = scp_args;
cmd.insert(cmd.end(), { local, host + ":" + remote });
return stap_system(s->verbose, cmd);
}
void open_control_master()
{
static unsigned index = 0;
if (s->tmpdir.empty()) // sanity check, shouldn't happen
throw runtime_error(_("No tmpdir available for ssh control master"));
ssh_control = s->tmpdir + "/ssh_remote_control_" + lex_cast(++index);
scp_args = { "scp", "-q", "-o", "ControlPath=" + ssh_control };
ssh_args = { "ssh", "-q", "-o", "ControlPath=" + ssh_control, host };
if (!port.empty())
{
scp_args.insert(scp_args.end(), { "-P", port });
ssh_args.insert(ssh_args.end(), { "-p", port });
}