SubProc.cxx

// cosmos
#include <cosmos/error/ApiError.hxx>
#include <cosmos/error/UsageError.hxx>
#include <cosmos/io/Poller.hxx>
#include <cosmos/private/cosmos.hxx>
#include <cosmos/proc/process.hxx>
#include <cosmos/proc/signal.hxx>
#include <cosmos/proc/SubProc.hxx>
 
namespace cosmos {
 
SubProc::~SubProc() {
        if (running()) {
                fatal_error("destroying SubProc while child process still running");
        }
}
 
void SubProc::kill(const Signal s) {
        signal::send(m_child_fd, s);
}
 
void SubProc::reset() {
        m_pid = ProcessID::INVALID;
        m_child_fd.close();
}
 
ChildData SubProc::wait(const WaitFlags flags) {
 
        if (flags[WaitFlag::NO_HANG]) {
                cosmos_throw (UsageError("cannot use NO_HANG with SubProc, use waitTimed() instead"));
        }
 
        try {
                auto child = proc::wait(m_child_fd, flags);
                if (!flags[WaitFlag::LEAVE_INFO] && (child->exited() || child->signaled())) {
                        reset();
                }
                return *child;
        } catch (const ApiError &err) {
                // for some reason the child was already collected, invalidate
                // our state to prevent infinite loops / uncleanable SubProc
                // objects
                if (err.errnum() == Errno::NO_CHILD) {
                        try {
                                reset();
                        } catch(...) {
                                // FileDescriptor will be invalidated already in this case
                        }
                }
 
                throw;
        }
}
 
std::optional<ChildData> SubProc::waitTimed(const IntervalTime max, const WaitFlags flags) {
        Poller poller(8);
 
        poller.addFD(m_child_fd, {Poller::MonitorFlag::INPUT});
 
        if (poller.wait(max).empty()) {
                return std::nullopt;
        }
 
        return wait(flags);
}
 
SubProc& SubProc::operator=(SubProc &&other) noexcept {
        if (running()) {
                fatal_error("moving into SubProc object with still running child process");
        }
        m_pid = other.m_pid;
        m_child_fd = other.m_child_fd;
        other.m_pid = ProcessID::INVALID;
        other.m_child_fd.reset();
        return *this;
}
 
} // end ns