95 lines
1.9 KiB
C++
95 lines
1.9 KiB
C++
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#include "Process.hpp"
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#include <linux/sched.h>
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#include <sched.h>
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#include <signal.h>
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#include <sys/types.h>
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#include "WordExp.hpp"
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namespace nanosm {
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inline static pid_t Clone3(const clone_args& args) {
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return syscall(SYS_clone3, &args, sizeof(clone_args));
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}
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Process::~Process() {
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Kill();
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Reset();
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}
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int Process::GetFD() const {
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return pidFd;
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}
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int Process::InterestedEvents() const {
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/// Pidfd only returns EPOLLIN.
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return EPOLLIN;
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}
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void Process::Spawn(const std::string& commandLine) {
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commLine = commandLine;
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Respawn();
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}
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void Process::Respawn() {
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pid = Clone3({
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.flags = CLONE_PIDFD,
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.pidfd = std::bit_cast<u64>(&pidFd),
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.exit_signal = SIGCHLD,
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});
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if(pid < 0)
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perror("Clone3()");
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if(pid == 0) {
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// Forked from the parent successfully, execute the given thing
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auto exp = nanosm::WordExp::Expand(commLine);
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std::vector<char*> argv(exp.words.size());
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for(usize i = 0; i < exp.words.size(); ++i)
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argv[i] = exp.words[i].data();
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execvp(exp.words[0].data(), argv.data());
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} else {
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// Parent: monitor FD
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eventLoop.AddObject(IoObject::Ptr(shared_from_this()));
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}
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}
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void Process::OnReady(int eventMask) {
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// In our case, any readiness signaled by the pidfd means the process exited
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// so this will never block (or really, wait).
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waitid(P_PIDFD, pidFd, &siginfo, WNOHANG);
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// Post a callback to call the user's exit callback (if one exists)
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eventLoop.Post([self = shared_from_this()]() {
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// Prepare for re-attaching, or etc.
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self->eventLoop.RemoveObject(self);
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self->Reset();
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if(self->onProcessExit)
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self->onProcessExit(self->siginfo.si_status);
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});
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}
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void Process::Kill() {
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if(pid != -1)
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kill(pid, SIGTERM);
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}
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void Process::SetExitCallback(std::function<void(int)> f) {
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onProcessExit = f;
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}
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void Process::Reset() {
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if(pidFd != -1) {
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close(pidFd);
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pidFd = -1;
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}
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pid = -1;
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siginfo = {};
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}
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} // namespace nanosm
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