tests/jai-test-probe.cc

#include <csignal> #include <cstdlib> #include <filesystem> #include <iostream> #include <set> #include <string> #include <string_view> #include <system_error> #include <vector> #include <dirent.h> #include <fcntl.h> #include <sys/ioctl.h> #include <sys/stat.h> #include <unistd.h> namespace { [[noreturn]] void die(std::string_view msg) { std::cerr << "FAIL: " << msg << '\n'; std::exit(1); } void check(bool ok, std::string_view msg) { if (!ok) die(msg); } int signal_from_name(std::string_view name) { if (name == "stop") return SIGSTOP; if (name == "tstp") return SIGTSTP; if (name == "ttin") return SIGTTIN; if (name == "ttou") return SIGTTOU; die("unknown signal name"); } std::string join_pids(const std::set<int> &pids) { std::string out; bool first = true; for (int pid : pids) { if (!first) out += ','; first = false; out += std::to_string(pid); } return out; } std::set<int> numeric_proc_entries() { std::set<int> out; DIR *dir = opendir("/proc"); check(dir != nullptr, "opendir(/proc) failed"); while (dirent *de = readdir(dir)) { char *end{}; long v = std::strtol(de->d_name, &end, 10); if (*de->d_name != '\0' && end && *end == '\0') out.insert(static_cast<int>(v)); } closedir(dir); return out; } int open_tty() { return open("/dev/tty", O_RDWR | O_CLOEXEC); } long foreground_pgrp(int ttyfd) { if (ttyfd < 0) return -1; auto pg = tcgetpgrp(ttyfd); if (pg == -1) return -1; return pg; } void print_probe() { struct stat tmp{}, vartmp{}; check(stat("/tmp", &tmp) == 0, "stat(/tmp) failed"); check(stat("/var/tmp", &vartmp) == 0, "stat(/var/tmp) failed"); int ttyfd = open_tty(); const auto pids = numeric_proc_entries(); std::cout << "pid=" << getpid() << '\n'; std::cout << "ppid=" << getppid() << '\n'; std::cout << "pgid=" << getpgid(0) << '\n'; std::cout << "sid=" << getsid(0) << '\n'; std::cout << "tty=" << (ttyfd >= 0 ? "yes" : "no") << '\n'; std::cout << "fg_pgrp=" << foreground_pgrp(ttyfd) << '\n'; std::cout << "tmp_same_inode=" << ((tmp.st_dev == vartmp.st_dev && tmp.st_ino == vartmp.st_ino) ? "yes" : "no") << '\n'; std::cout << "proc_pids=" << join_pids(pids) << '\n'; if (ttyfd >= 0) close(ttyfd); } void run_suspend(int argc, char **argv) { bool new_pgrp = false; bool foreground = false; int stop_signal = SIGSTOP; for (int i = 2; i < argc; ++i) { std::string_view arg = argv[i]; if (arg == "--new-pgrp") new_pgrp = true; else if (arg == "--foreground") foreground = true; else if (arg.starts_with("--signal=")) stop_signal = signal_from_name(arg.substr(9)); else die("unknown suspend argument"); } if (new_pgrp) check(setpgid(0, 0) == 0, "setpgid failed"); int ttyfd = open_tty(); if (foreground && ttyfd >= 0) { struct sigaction old_act{}, ign{}; ign.sa_handler = SIG_IGN; check(sigaction(SIGTTOU, &ign, &old_act) == 0, "sigaction(SIGTTOU) failed"); check(tcsetpgrp(ttyfd, getpgrp()) == 0, "tcsetpgrp failed"); check(sigaction(SIGTTOU, &old_act, nullptr) == 0, "restoring SIGTTOU failed"); } std::cout << "READY" << " pid=" << getpid() << " ppid=" << getppid() << " pgid=" << getpgid(0) << " sid=" << getsid(0) << " fg_pgrp=" << foreground_pgrp(ttyfd) << " signal=" << stop_signal << '\n' << std::flush; check(raise(stop_signal) == 0, "raise failed"); std::cout << "RESUMED" << " pid=" << getpid() << " pgid=" << getpgid(0) << " fg_pgrp=" << foreground_pgrp(ttyfd) << '\n' << std::flush; if (ttyfd >= 0) close(ttyfd); } } // namespace int main(int argc, char **argv) { std::ios::sync_with_stdio(false); if (argc < 2) die("missing subcommand"); std::string_view cmd = argv[1]; if (cmd == "probe") print_probe(); else if (cmd == "suspend") run_suspend(argc, argv); else die("unknown subcommand"); return 0; }