359 lines
11 KiB
C++
359 lines
11 KiB
C++
#include "command.hh"
|
|
#include "shared.hh"
|
|
#include "local-store.hh"
|
|
#include "remote-store.hh"
|
|
#include "util.hh"
|
|
#include "serialise.hh"
|
|
#include "archive.hh"
|
|
#include "globals.hh"
|
|
#include "derivations.hh"
|
|
#include "finally.hh"
|
|
#include "legacy.hh"
|
|
#include "daemon.hh"
|
|
|
|
#include <algorithm>
|
|
#include <climits>
|
|
#include <cstring>
|
|
|
|
#include <unistd.h>
|
|
#include <signal.h>
|
|
#include <sys/types.h>
|
|
#include <sys/wait.h>
|
|
#include <sys/stat.h>
|
|
#include <sys/socket.h>
|
|
#include <sys/un.h>
|
|
#include <errno.h>
|
|
#include <pwd.h>
|
|
#include <grp.h>
|
|
#include <fcntl.h>
|
|
|
|
#if __APPLE__ || __FreeBSD__
|
|
#include <sys/ucred.h>
|
|
#endif
|
|
|
|
using namespace nix;
|
|
using namespace nix::daemon;
|
|
|
|
#ifndef __linux__
|
|
#define SPLICE_F_MOVE 0
|
|
static ssize_t splice(int fd_in, void *off_in, int fd_out, void *off_out, size_t len, unsigned int flags)
|
|
{
|
|
// We ignore most parameters, we just have them for conformance with the linux syscall
|
|
std::vector<char> buf(8192);
|
|
auto read_count = read(fd_in, buf.data(), buf.size());
|
|
if (read_count == -1)
|
|
return read_count;
|
|
auto write_count = decltype(read_count)(0);
|
|
while (write_count < read_count) {
|
|
auto res = write(fd_out, buf.data() + write_count, read_count - write_count);
|
|
if (res == -1)
|
|
return res;
|
|
write_count += res;
|
|
}
|
|
return read_count;
|
|
}
|
|
#endif
|
|
|
|
|
|
static void sigChldHandler(int sigNo)
|
|
{
|
|
// Ensure we don't modify errno of whatever we've interrupted
|
|
auto saved_errno = errno;
|
|
// Reap all dead children.
|
|
while (waitpid(-1, 0, WNOHANG) > 0) ;
|
|
errno = saved_errno;
|
|
}
|
|
|
|
|
|
static void setSigChldAction(bool autoReap)
|
|
{
|
|
struct sigaction act, oact;
|
|
act.sa_handler = autoReap ? sigChldHandler : SIG_DFL;
|
|
sigfillset(&act.sa_mask);
|
|
act.sa_flags = 0;
|
|
if (sigaction(SIGCHLD, &act, &oact))
|
|
throw SysError("setting SIGCHLD handler");
|
|
}
|
|
|
|
|
|
bool matchUser(const std::string & user, const std::string & group, const Strings & users)
|
|
{
|
|
if (find(users.begin(), users.end(), "*") != users.end())
|
|
return true;
|
|
|
|
if (find(users.begin(), users.end(), user) != users.end())
|
|
return true;
|
|
|
|
for (auto & i : users)
|
|
if (i.substr(0, 1) == "@") {
|
|
if (group == i.substr(1)) return true;
|
|
struct group * gr = getgrnam(i.c_str() + 1);
|
|
if (!gr) continue;
|
|
for (char * * mem = gr->gr_mem; *mem; mem++)
|
|
if (user == std::string(*mem)) return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
|
|
struct PeerInfo
|
|
{
|
|
bool pidKnown;
|
|
pid_t pid;
|
|
bool uidKnown;
|
|
uid_t uid;
|
|
bool gidKnown;
|
|
gid_t gid;
|
|
};
|
|
|
|
|
|
// Get the identity of the caller, if possible.
|
|
static PeerInfo getPeerInfo(int remote)
|
|
{
|
|
PeerInfo peer = { false, 0, false, 0, false, 0 };
|
|
|
|
#if defined(SO_PEERCRED)
|
|
|
|
ucred cred;
|
|
socklen_t credLen = sizeof(cred);
|
|
if (getsockopt(remote, SOL_SOCKET, SO_PEERCRED, &cred, &credLen) == -1)
|
|
throw SysError("getting peer credentials");
|
|
peer = { true, cred.pid, true, cred.uid, true, cred.gid };
|
|
|
|
#elif defined(LOCAL_PEERCRED)
|
|
|
|
#if !defined(SOL_LOCAL)
|
|
#define SOL_LOCAL 0
|
|
#endif
|
|
|
|
xucred cred;
|
|
socklen_t credLen = sizeof(cred);
|
|
if (getsockopt(remote, SOL_LOCAL, LOCAL_PEERCRED, &cred, &credLen) == -1)
|
|
throw SysError("getting peer credentials");
|
|
peer = { false, 0, true, cred.cr_uid, false, 0 };
|
|
|
|
#endif
|
|
|
|
return peer;
|
|
}
|
|
|
|
|
|
#define SD_LISTEN_FDS_START 3
|
|
|
|
|
|
static ref<Store> openUncachedStore()
|
|
{
|
|
Store::Params params; // FIXME: get params from somewhere
|
|
// Disable caching since the client already does that.
|
|
params["path-info-cache-size"] = "0";
|
|
return openStore(settings.storeUri, params);
|
|
}
|
|
|
|
|
|
static void daemonLoop()
|
|
{
|
|
if (chdir("/") == -1)
|
|
throw SysError("cannot change current directory");
|
|
|
|
AutoCloseFD fdSocket;
|
|
|
|
// Handle socket-based activation by systemd.
|
|
auto listenFds = getEnv("LISTEN_FDS");
|
|
if (listenFds) {
|
|
if (getEnv("LISTEN_PID") != std::to_string(getpid()) || listenFds != "1")
|
|
throw Error("unexpected systemd environment variables");
|
|
fdSocket = SD_LISTEN_FDS_START;
|
|
closeOnExec(fdSocket.get());
|
|
}
|
|
|
|
// Otherwise, create and bind to a Unix domain socket.
|
|
else {
|
|
createDirs(dirOf(settings.nixDaemonSocketFile));
|
|
fdSocket = createUnixDomainSocket(settings.nixDaemonSocketFile, 0666);
|
|
}
|
|
|
|
// Get rid of children automatically; don't let them become zombies.
|
|
setSigChldAction(true);
|
|
|
|
// Loop accepting connections.
|
|
while (1) {
|
|
|
|
try {
|
|
// Accept a connection.
|
|
struct sockaddr_un remoteAddr;
|
|
socklen_t remoteAddrLen = sizeof(remoteAddr);
|
|
|
|
AutoCloseFD remote = accept(fdSocket.get(),
|
|
(struct sockaddr *) &remoteAddr, &remoteAddrLen);
|
|
checkInterrupt();
|
|
if (!remote) {
|
|
if (errno == EINTR) continue;
|
|
throw SysError("accepting connection");
|
|
}
|
|
|
|
closeOnExec(remote.get());
|
|
|
|
TrustedFlag trusted = NotTrusted;
|
|
PeerInfo peer = getPeerInfo(remote.get());
|
|
|
|
struct passwd * pw = peer.uidKnown ? getpwuid(peer.uid) : 0;
|
|
std::string user = pw ? pw->pw_name : std::to_string(peer.uid);
|
|
|
|
struct group * gr = peer.gidKnown ? getgrgid(peer.gid) : 0;
|
|
std::string group = gr ? gr->gr_name : std::to_string(peer.gid);
|
|
|
|
Strings trustedUsers = settings.trustedUsers;
|
|
Strings allowedUsers = settings.allowedUsers;
|
|
|
|
if (matchUser(user, group, trustedUsers))
|
|
trusted = Trusted;
|
|
|
|
if ((!trusted && !matchUser(user, group, allowedUsers)) || group == settings.buildUsersGroup)
|
|
throw Error("user '%1%' is not allowed to connect to the Nix daemon", user);
|
|
|
|
printInfo(format((std::string) "accepted connection from pid %1%, user %2%" + (trusted ? " (trusted)" : ""))
|
|
% (peer.pidKnown ? std::to_string(peer.pid) : "<unknown>")
|
|
% (peer.uidKnown ? user : "<unknown>"));
|
|
|
|
// Fork a child to handle the connection.
|
|
ProcessOptions options;
|
|
options.errorPrefix = "unexpected Nix daemon error: ";
|
|
options.dieWithParent = false;
|
|
options.runExitHandlers = true;
|
|
options.allowVfork = false;
|
|
startProcess([&]() {
|
|
fdSocket = -1;
|
|
|
|
// Background the daemon.
|
|
if (setsid() == -1)
|
|
throw SysError("creating a new session");
|
|
|
|
// Restore normal handling of SIGCHLD.
|
|
setSigChldAction(false);
|
|
|
|
// For debugging, stuff the pid into argv[1].
|
|
if (peer.pidKnown && savedArgv[1]) {
|
|
auto processName = std::to_string(peer.pid);
|
|
strncpy(savedArgv[1], processName.c_str(), strlen(savedArgv[1]));
|
|
}
|
|
|
|
// Handle the connection.
|
|
FdSource from(remote.get());
|
|
FdSink to(remote.get());
|
|
processConnection(openUncachedStore(), from, to, trusted, NotRecursive, [&](Store & store) {
|
|
#if 0
|
|
/* Prevent users from doing something very dangerous. */
|
|
if (geteuid() == 0 &&
|
|
querySetting("build-users-group", "") == "")
|
|
throw Error("if you run 'nix-daemon' as root, then you MUST set 'build-users-group'!");
|
|
#endif
|
|
store.createUser(user, peer.uid);
|
|
});
|
|
|
|
exit(0);
|
|
}, options);
|
|
|
|
} catch (Interrupted & e) {
|
|
return;
|
|
} catch (Error & error) {
|
|
ErrorInfo ei = error.info();
|
|
// FIXME: add to trace?
|
|
ei.msg = hintfmt("error processing connection: %1%", ei.msg.str());
|
|
logError(ei);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void runDaemon(bool stdio)
|
|
{
|
|
if (stdio) {
|
|
if (auto store = openUncachedStore().dynamic_pointer_cast<RemoteStore>()) {
|
|
auto conn = store->openConnectionWrapper();
|
|
int from = conn->from.fd;
|
|
int to = conn->to.fd;
|
|
|
|
auto nfds = std::max(from, STDIN_FILENO) + 1;
|
|
while (true) {
|
|
fd_set fds;
|
|
FD_ZERO(&fds);
|
|
FD_SET(from, &fds);
|
|
FD_SET(STDIN_FILENO, &fds);
|
|
if (select(nfds, &fds, nullptr, nullptr, nullptr) == -1)
|
|
throw SysError("waiting for data from client or server");
|
|
if (FD_ISSET(from, &fds)) {
|
|
auto res = splice(from, nullptr, STDOUT_FILENO, nullptr, SSIZE_MAX, SPLICE_F_MOVE);
|
|
if (res == -1)
|
|
throw SysError("splicing data from daemon socket to stdout");
|
|
else if (res == 0)
|
|
throw EndOfFile("unexpected EOF from daemon socket");
|
|
}
|
|
if (FD_ISSET(STDIN_FILENO, &fds)) {
|
|
auto res = splice(STDIN_FILENO, nullptr, to, nullptr, SSIZE_MAX, SPLICE_F_MOVE);
|
|
if (res == -1)
|
|
throw SysError("splicing data from stdin to daemon socket");
|
|
else if (res == 0)
|
|
return;
|
|
}
|
|
}
|
|
} else {
|
|
FdSource from(STDIN_FILENO);
|
|
FdSink to(STDOUT_FILENO);
|
|
/* Auth hook is empty because in this mode we blindly trust the
|
|
standard streams. Limiting access to those is explicitly
|
|
not `nix-daemon`'s responsibility. */
|
|
processConnection(openUncachedStore(), from, to, Trusted, NotRecursive, [&](Store & _){});
|
|
}
|
|
} else
|
|
daemonLoop();
|
|
}
|
|
|
|
static int main_nix_daemon(int argc, char * * argv)
|
|
{
|
|
{
|
|
auto stdio = false;
|
|
|
|
parseCmdLine(argc, argv, [&](Strings::iterator & arg, const Strings::iterator & end) {
|
|
if (*arg == "--daemon")
|
|
; // ignored for backwards compatibility
|
|
else if (*arg == "--help")
|
|
showManPage("nix-daemon");
|
|
else if (*arg == "--version")
|
|
printVersion("nix-daemon");
|
|
else if (*arg == "--stdio")
|
|
stdio = true;
|
|
else return false;
|
|
return true;
|
|
});
|
|
|
|
runDaemon(stdio);
|
|
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
static RegisterLegacyCommand r_nix_daemon("nix-daemon", main_nix_daemon);
|
|
|
|
struct CmdDaemon : StoreCommand
|
|
{
|
|
std::string description() override
|
|
{
|
|
return "daemon to perform store operations on behalf of non-root clients";
|
|
}
|
|
|
|
Category category() override { return catUtility; }
|
|
|
|
std::string doc() override
|
|
{
|
|
return
|
|
#include "daemon.md"
|
|
;
|
|
}
|
|
|
|
void run(ref<Store> store) override
|
|
{
|
|
runDaemon(false);
|
|
}
|
|
};
|
|
|
|
static auto rCmdDaemon = registerCommand2<CmdDaemon>({"daemon"});
|