which means "follow POSIX", which we don't want here
*/
if (syscall(SYS_kill, -1, SIGKILL, false) == 0) break;
+#elif __GNU__
+ /* Killing all a user's processes using PID=-1 does currently
+ not work on the Hurd. */
+ if (kill(getpid(), SIGKILL) == 0) break;
#else
if (kill(-1, SIGKILL) == 0) break;
#endif
});
int status = pid.wait(true);
+#if __GNU__
+ /* When the child killed itself, status = SIGKILL. */
+ if (status == SIGKILL) return;
+#endif
if (status != 0)
throw Error(format("cannot kill processes for uid `%1%': %2%") % uid % statusToString(status));
}
}
+static const string pathNullDevice = "/dev/null";
+
+/* Common initialisation performed in child processes. */
+void commonChildInit(Pipe & logPipe)
+{
+ /* Put the child in a separate session (and thus a separate
+ process group) so that it has no controlling terminal (meaning
+ that e.g. ssh cannot open /dev/tty) and it doesn't receive
+ terminal signals. */
+ if (setsid() == -1)
+ throw SysError(format("creating a new session"));
+
+ /* Dup the write side of the logger pipe into stderr. */
+ if (dup2(logPipe.writeSide, STDERR_FILENO) == -1)
+ throw SysError("cannot pipe standard error into log file");
+
+ /* Dup stderr to stdout. */
+ if (dup2(STDERR_FILENO, STDOUT_FILENO) == -1)
+ throw SysError("cannot dup stderr into stdout");
+
+ /* Reroute stdin to /dev/null. */
+ int fdDevNull = open(pathNullDevice.c_str(), O_RDWR);
+ if (fdDevNull == -1)
+ throw SysError(format("cannot open `%1%'") % pathNullDevice);
+ if (dup2(fdDevNull, STDIN_FILENO) == -1)
+ throw SysError("cannot dup null device into stdin");
+ close(fdDevNull);
+}
+
+//////////////////////////////////////////////////////////////////////
+
+Agent::Agent(const string &command, const Strings &args, const std::map<string, string> &env)
+{
+ debug(format("starting agent '%1%'") % command);
+
+ /* Create a pipe to get the output of the child. */
+ fromAgent.create();
+
+ /* Create the communication pipes. */
+ toAgent.create();
+
+ /* Create a pipe to get the output of the builder. */
+ builderOut.create();
+
+ /* Fork the hook. */
+ pid = startProcess([&]() {
+
+ commonChildInit(fromAgent);
+
+ for (auto pair: env) {
+ setenv(pair.first.c_str(), pair.second.c_str(), 1);
+ }
+
+ if (chdir("/") == -1) throw SysError("changing into `/");
+
+ /* Dup the communication pipes. */
+ if (dup2(toAgent.readSide, STDIN_FILENO) == -1)
+ throw SysError("dupping to-hook read side");
+
+ /* Use fd 4 for the builder's stdout/stderr. */
+ if (dup2(builderOut.writeSide, 4) == -1)
+ throw SysError("dupping builder's stdout/stderr");
+
+ Strings allArgs;
+ allArgs.push_back(command);
+ allArgs.insert(allArgs.end(), args.begin(), args.end()); // append
+
+ execv(command.c_str(), stringsToCharPtrs(allArgs).data());
+
+ throw SysError(format("executing `%1%'") % command);
+ });
+
+ pid.setSeparatePG(true);
+ fromAgent.writeSide.close();
+ toAgent.readSide.close();
+}
+
+
+Agent::~Agent()
+{
+ try {
+ toAgent.writeSide.close();
+ pid.kill(true);
+ } catch (...) {
+ ignoreException();
+ }
+}
+
}