/** * Copyright (c) 2012-2015, Christopher Jeffrey (MIT License) * Copyright (c) 2017, Daniel Imms (MIT License) * Copyright (c) 2024, Leroy Hopson (MIT License) * * SPDX-License-Identifier: MIT * * pty.cc: * This file is responsible for starting processes * with pseudo-terminal file descriptors. * * See: * man pty * man tty_ioctl * man termios * man forkpty */ /** * Includes */ using namespace godot; #include #include #include #include #include #include #include #include #include #include #include #include /* forkpty */ /* http://www.gnu.org/software/gnulib/manual/html_node/forkpty.html */ #if defined(__linux__) #include #elif defined(__APPLE__) #include #elif defined(__FreeBSD__) #include #endif /* Some platforms name VWERASE and VDISCARD differently */ #if !defined(VWERASE) && defined(VWERSE) #define VWERASE VWERSE #endif #if !defined(VDISCARD) && defined(VDISCRD) #define VDISCARD VDISCRD #endif /* for pty_getproc */ #if defined(__linux__) #include #include #elif defined(__APPLE__) #include #include #include #include #include #include #endif /* NSIG - macro for highest signal + 1, should be defined */ #ifndef NSIG #define NSIG 32 #endif /* macOS 10.14 back does not define this constant */ #ifndef POSIX_SPAWN_SETSID #define POSIX_SPAWN_SETSID 1024 #endif /* environ for execvpe */ /* node/src/node_child_process.cc */ #if !defined(__APPLE__) extern char **environ; #endif #if defined(__APPLE__) extern "C" { // Changes the current thread's directory to a path or directory file // descriptor. libpthread only exposes a syscall wrapper starting in // macOS 10.12, but the system call dates back to macOS 10.5. On older OSes, // the syscall is issued directly. int pthread_chdir_np(const char* dir) API_AVAILABLE(macosx(10.12)); int pthread_fchdir_np(int fd) API_AVAILABLE(macosx(10.12)); } #define HANDLE_EINTR(x) ({ \ int eintr_wrapper_counter = 0; \ decltype(x) eintr_wrapper_result; \ do { \ eintr_wrapper_result = (x); \ } while (eintr_wrapper_result == -1 && errno == EINTR && \ eintr_wrapper_counter++ < 100); \ eintr_wrapper_result; \ }) #endif /** * Structs */ struct pty_baton { Nan::Persistent cb; int exit_code; int signal_code; pid_t pid; uv_async_t async; uv_thread_t tid; }; /** * Methods */ NAN_METHOD(PtyFork); NAN_METHOD(PtyOpen); NAN_METHOD(PtyResize); NAN_METHOD(PtyGetProc); /** * Functions */ static int pty_nonblock(int); #if defined(__APPLE__) static char * pty_getproc(int); #else static char * pty_getproc(int, char *); #endif static void pty_waitpid(void *); static void pty_after_waitpid(uv_async_t *); static void pty_after_close(uv_handle_t *); #if defined(__APPLE__) || defined(__OpenBSD__) static void pty_posix_spawn(char** argv, char** env, const struct termios *termp, const struct winsize *winp, int* master, pid_t* pid, int* err); #endif Dictionary fork( const String &p_file, const PackedStringArray &p_args, const PackedStringArray &p_env, const String &p_cwd, const int p_cols, const int p_rows, const int p_uid, const int p_gid, const bool p_utf8, const String &p_helper_path, const Callable &p_on_exit ) { // file std::string file = p_file.utf8().get_data(); // args v8::Local argv_ = v8::Local::Cast(info[1]); // env v8::Local env_ = v8::Local::Cast(info[2]); int envc = env_->Length(); char **env = new char*[envc+1]; env[envc] = NULL; for (int i = 0; i < envc; i++) { Nan::Utf8String pair(Nan::Get(env_, i).ToLocalChecked()); env[i] = strdup(*pair); } // cwd Nan::Utf8String cwd_(info[3]); // size struct winsize winp; winp.ws_col = info[4]->IntegerValue(Nan::GetCurrentContext()).FromJust(); winp.ws_row = info[5]->IntegerValue(Nan::GetCurrentContext()).FromJust(); winp.ws_xpixel = 0; winp.ws_ypixel = 0; #if !defined(__APPLE__) // uid / gid int uid = info[6]->IntegerValue(Nan::GetCurrentContext()).FromJust(); int gid = info[7]->IntegerValue(Nan::GetCurrentContext()).FromJust(); #endif // termios struct termios t = termios(); struct termios *term = &t; term->c_iflag = ICRNL | IXON | IXANY | IMAXBEL | BRKINT; if (Nan::To(info[8]).FromJust()) { #if defined(IUTF8) term->c_iflag |= IUTF8; #endif } term->c_oflag = OPOST | ONLCR; term->c_cflag = CREAD | CS8 | HUPCL; term->c_lflag = ICANON | ISIG | IEXTEN | ECHO | ECHOE | ECHOK | ECHOKE | ECHOCTL; term->c_cc[VEOF] = 4; term->c_cc[VEOL] = -1; term->c_cc[VEOL2] = -1; term->c_cc[VERASE] = 0x7f; term->c_cc[VWERASE] = 23; term->c_cc[VKILL] = 21; term->c_cc[VREPRINT] = 18; term->c_cc[VINTR] = 3; term->c_cc[VQUIT] = 0x1c; term->c_cc[VSUSP] = 26; term->c_cc[VSTART] = 17; term->c_cc[VSTOP] = 19; term->c_cc[VLNEXT] = 22; term->c_cc[VDISCARD] = 15; term->c_cc[VMIN] = 1; term->c_cc[VTIME] = 0; #if (__APPLE__) term->c_cc[VDSUSP] = 25; term->c_cc[VSTATUS] = 20; #endif cfsetispeed(term, B38400); cfsetospeed(term, B38400); // helperPath Nan::Utf8String helper_path(info[9]); pid_t pid; int master; #if defined(__APPLE__) int argc = argv_->Length(); int argl = argc + 4; char **argv = new char*[argl]; argv[0] = strdup(*helper_path); argv[1] = strdup(*cwd_); argv[2] = strdup(*file); argv[argl - 1] = NULL; for (int i = 0; i < argc; i++) { Nan::Utf8String arg(Nan::Get(argv_, i).ToLocalChecked()); argv[i + 3] = strdup(*arg); } int err = -1; pty_posix_spawn(argv, env, term, &winp, &master, &pid, &err); if (err != 0) { Nan::ThrowError("posix_spawnp failed."); goto done; } if (pty_nonblock(master) == -1) { Nan::ThrowError("Could not set master fd to nonblocking."); goto done; } #else int argc = argv_->Length(); int argl = argc + 2; char **argv = new char*[argl]; argv[0] = strdup(*file); argv[argl - 1] = NULL; for (int i = 0; i < argc; i++) { Nan::Utf8String arg(Nan::Get(argv_, i).ToLocalChecked()); argv[i + 1] = strdup(*arg); } char* cwd = strdup(*cwd_); sigset_t newmask, oldmask; struct sigaction sig_action; // temporarily block all signals // this is needed due to a race condition in openpty // and to avoid running signal handlers in the child // before exec* happened sigfillset(&newmask); pthread_sigmask(SIG_SETMASK, &newmask, &oldmask); pid = forkpty(&master, nullptr, static_cast(term), static_cast(&winp)); if (!pid) { // remove all signal handler from child sig_action.sa_handler = SIG_DFL; sig_action.sa_flags = 0; sigemptyset(&sig_action.sa_mask); for (int i = 0 ; i < NSIG ; i++) { // NSIG is a macro for all signals + 1 sigaction(i, &sig_action, NULL); } } else { for (int i = 0; i < argl; i++) free(argv[i]); delete[] argv; for (int i = 0; i < envc; i++) free(env[i]); delete[] env; free(cwd); } // re-enable signals pthread_sigmask(SIG_SETMASK, &oldmask, NULL); switch (pid) { case -1: Nan::ThrowError("forkpty(3) failed."); goto done; case 0: if (strlen(cwd)) { if (chdir(cwd) == -1) { perror("chdir(2) failed."); _exit(1); } } if (uid != -1 && gid != -1) { if (setgid(gid) == -1) { perror("setgid(2) failed."); _exit(1); } if (setuid(uid) == -1) { perror("setuid(2) failed."); _exit(1); } } { char **old = environ; environ = env; execvp(argv[0], argv); environ = old; perror("execvp(3) failed."); _exit(1); } default: if (pty_nonblock(master) == -1) { Nan::ThrowError("Could not set master fd to nonblocking."); goto done; } } #endif { v8::Local obj = Nan::New(); Nan::Set(obj, Nan::New("fd").ToLocalChecked(), Nan::New(master)); Nan::Set(obj, Nan::New("pid").ToLocalChecked(), Nan::New(pid)); Nan::Set(obj, Nan::New("pty").ToLocalChecked(), Nan::New(ptsname(master)).ToLocalChecked()); pty_baton *baton = new pty_baton(); baton->exit_code = 0; baton->signal_code = 0; baton->cb.Reset(v8::Local::Cast(info[10])); baton->pid = pid; baton->async.data = baton; uv_async_init(uv_default_loop(), &baton->async, pty_after_waitpid); uv_thread_create(&baton->tid, pty_waitpid, static_cast(baton)); return info.GetReturnValue().Set(obj); } done: #if defined(__APPLE__) for (int i = 0; i < argl; i++) free(argv[i]); delete[] argv; for (int i = 0; i < envc; i++) free(env[i]); delete[] env; #endif return info.GetReturnValue().SetUndefined(); } NAN_METHOD(PtyOpen) { Nan::HandleScope scope; if (info.Length() != 2 || !info[0]->IsNumber() || !info[1]->IsNumber()) { return Nan::ThrowError("Usage: pty.open(cols, rows)"); } // size struct winsize winp; winp.ws_col = info[0]->IntegerValue(Nan::GetCurrentContext()).FromJust(); winp.ws_row = info[1]->IntegerValue(Nan::GetCurrentContext()).FromJust(); winp.ws_xpixel = 0; winp.ws_ypixel = 0; // pty int master, slave; int ret = openpty(&master, &slave, nullptr, NULL, static_cast(&winp)); if (ret == -1) { return Nan::ThrowError("openpty(3) failed."); } if (pty_nonblock(master) == -1) { return Nan::ThrowError("Could not set master fd to nonblocking."); } if (pty_nonblock(slave) == -1) { return Nan::ThrowError("Could not set slave fd to nonblocking."); } v8::Local obj = Nan::New(); Nan::Set(obj, Nan::New("master").ToLocalChecked(), Nan::New(master)); Nan::Set(obj, Nan::New("slave").ToLocalChecked(), Nan::New(slave)); Nan::Set(obj, Nan::New("pty").ToLocalChecked(), Nan::New(ptsname(master)).ToLocalChecked()); return info.GetReturnValue().Set(obj); } NAN_METHOD(PtyResize) { Nan::HandleScope scope; if (info.Length() != 3 || !info[0]->IsNumber() || !info[1]->IsNumber() || !info[2]->IsNumber()) { return Nan::ThrowError("Usage: pty.resize(fd, cols, rows)"); } int fd = info[0]->IntegerValue(Nan::GetCurrentContext()).FromJust(); struct winsize winp; winp.ws_col = info[1]->IntegerValue(Nan::GetCurrentContext()).FromJust(); winp.ws_row = info[2]->IntegerValue(Nan::GetCurrentContext()).FromJust(); winp.ws_xpixel = 0; winp.ws_ypixel = 0; if (ioctl(fd, TIOCSWINSZ, &winp) == -1) { switch (errno) { case EBADF: return Nan::ThrowError("ioctl(2) failed, EBADF"); case EFAULT: return Nan::ThrowError("ioctl(2) failed, EFAULT"); case EINVAL: return Nan::ThrowError("ioctl(2) failed, EINVAL"); case ENOTTY: return Nan::ThrowError("ioctl(2) failed, ENOTTY"); } return Nan::ThrowError("ioctl(2) failed"); } return info.GetReturnValue().SetUndefined(); } /** * Foreground Process Name */ NAN_METHOD(PtyGetProc) { Nan::HandleScope scope; #if defined(__APPLE__) if (info.Length() != 1 || !info[0]->IsNumber()) { return Nan::ThrowError("Usage: pty.process(pid)"); } int pid = info[0]->IntegerValue(Nan::GetCurrentContext()).FromJust(); char *name = pty_getproc(pid); #else if (info.Length() != 2 || !info[0]->IsNumber() || !info[1]->IsString()) { return Nan::ThrowError("Usage: pty.process(fd, tty)"); } int fd = info[0]->IntegerValue(Nan::GetCurrentContext()).FromJust(); Nan::Utf8String tty_(info[1]); char *tty = strdup(*tty_); char *name = pty_getproc(fd, tty); free(tty); #endif if (name == NULL) { return info.GetReturnValue().SetUndefined(); } v8::Local name_ = Nan::New(name).ToLocalChecked(); free(name); return info.GetReturnValue().Set(name_); } /** * Nonblocking FD */ static int pty_nonblock(int fd) { int flags = fcntl(fd, F_GETFL, 0); if (flags == -1) return -1; return fcntl(fd, F_SETFL, flags | O_NONBLOCK); } /** * pty_waitpid * Wait for SIGCHLD to read exit status. */ static void pty_waitpid(void *data) { int ret; int stat_loc; pty_baton *baton = static_cast(data); errno = 0; #if defined(__APPLE__) // Based on // https://source.chromium.org/chromium/chromium/src/+/main:base/process/kill_mac.cc;l=35-69? int kq = HANDLE_EINTR(kqueue()); struct kevent change = {0}; EV_SET(&change, baton->pid, EVFILT_PROC, EV_ADD, NOTE_EXIT, 0, NULL); ret = HANDLE_EINTR(kevent(kq, &change, 1, NULL, 0, NULL)); if (ret == -1) { if (errno == ESRCH) { // At this point, one of the following has occurred: // 1. The process has died but has not yet been reaped. // 2. The process has died and has already been reaped. // 3. The process is in the process of dying. It's no longer // kqueueable, but it may not be waitable yet either. Mark calls // this case the "zombie death race". ret = HANDLE_EINTR(waitpid(baton->pid, &stat_loc, WNOHANG)); if (ret == 0) { ret = kill(baton->pid, SIGKILL); if (ret != -1) { HANDLE_EINTR(waitpid(baton->pid, &stat_loc, 0)); } } } } else { struct kevent event = {0}; ret = HANDLE_EINTR(kevent(kq, NULL, 0, &event, 1, NULL)); if (ret == 1) { if ((event.fflags & NOTE_EXIT) && (event.ident == static_cast(baton->pid))) { // The process is dead or dying. This won't block for long, if at // all. HANDLE_EINTR(waitpid(baton->pid, &stat_loc, 0)); } } } #else if ((ret = waitpid(baton->pid, &stat_loc, 0)) != baton->pid) { if (ret == -1 && errno == EINTR) { return pty_waitpid(baton); } if (ret == -1 && errno == ECHILD) { // XXX node v0.8.x seems to have this problem. // waitpid is already handled elsewhere. ; } else { assert(false); } } #endif if (WIFEXITED(stat_loc)) { baton->exit_code = WEXITSTATUS(stat_loc); // errno? } if (WIFSIGNALED(stat_loc)) { baton->signal_code = WTERMSIG(stat_loc); } uv_async_send(&baton->async); } /** * pty_after_waitpid * Callback after exit status has been read. */ static void pty_after_waitpid(uv_async_t *async) { Nan::HandleScope scope; pty_baton *baton = static_cast(async->data); v8::Local argv[] = { Nan::New(baton->exit_code), Nan::New(baton->signal_code), }; v8::Local cb = Nan::New(baton->cb); baton->cb.Reset(); memset(&baton->cb, -1, sizeof(baton->cb)); Nan::AsyncResource resource("pty_after_waitpid"); resource.runInAsyncScope(Nan::GetCurrentContext()->Global(), cb, 2, argv); uv_close((uv_handle_t *)async, pty_after_close); } /** * pty_after_close * uv_close() callback - free handle data */ static void pty_after_close(uv_handle_t *handle) { uv_async_t *async = (uv_async_t *)handle; pty_baton *baton = static_cast(async->data); delete baton; } /** * pty_getproc * Taken from tmux. */ // Taken from: tmux (http://tmux.sourceforge.net/) // Copyright (c) 2009 Nicholas Marriott // Copyright (c) 2009 Joshua Elsasser // Copyright (c) 2009 Todd Carson // // Permission to use, copy, modify, and distribute this software for any // purpose with or without fee is hereby granted, provided that the above // copyright notice and this permission notice appear in all copies. // // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES // WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF // MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR // ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES // WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER // IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING // OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. #if defined(__linux__) static char * pty_getproc(int fd, char *tty) { FILE *f; char *path, *buf; size_t len; int ch; pid_t pgrp; int r; if ((pgrp = tcgetpgrp(fd)) == -1) { return NULL; } r = asprintf(&path, "/proc/%lld/cmdline", (long long)pgrp); if (r == -1 || path == NULL) return NULL; if ((f = fopen(path, "r")) == NULL) { free(path); return NULL; } free(path); len = 0; buf = NULL; while ((ch = fgetc(f)) != EOF) { if (ch == '\0') break; buf = (char *)realloc(buf, len + 2); if (buf == NULL) return NULL; buf[len++] = ch; } if (buf != NULL) { buf[len] = '\0'; } fclose(f); return buf; } #elif defined(__APPLE__) static char * pty_getproc(int pid) { char pname[MAXCOMLEN + 1]; if (!proc_name(pid, pname, sizeof(pname))) { return NULL; } return strdup(pname); } #else static char * pty_getproc(int fd, char *tty) { return NULL; } #endif #if defined(__APPLE__) static void pty_posix_spawn(char** argv, char** env, const struct termios *termp, const struct winsize *winp, int* master, pid_t* pid, int* err) { int low_fds[3]; size_t count = 0; for (; count < 3; count++) { low_fds[count] = posix_openpt(O_RDWR); if (low_fds[count] >= STDERR_FILENO) break; } int flags = POSIX_SPAWN_CLOEXEC_DEFAULT | POSIX_SPAWN_SETSIGDEF | POSIX_SPAWN_SETSIGMASK | POSIX_SPAWN_SETSID; *master = posix_openpt(O_RDWR); if (*master == -1) { return; } int res = grantpt(*master) || unlockpt(*master); if (res == -1) { return; } // Use TIOCPTYGNAME instead of ptsname() to avoid threading problems. int slave; char slave_pty_name[128]; res = ioctl(*master, TIOCPTYGNAME, slave_pty_name); if (res == -1) { return; } slave = open(slave_pty_name, O_RDWR | O_NOCTTY); if (slave == -1) { return; } if (termp) { res = tcsetattr(slave, TCSANOW, termp); if (res == -1) { return; }; } if (winp) { res = ioctl(slave, TIOCSWINSZ, winp); if (res == -1) { return; } } posix_spawn_file_actions_t acts; posix_spawn_file_actions_init(&acts); posix_spawn_file_actions_adddup2(&acts, slave, STDIN_FILENO); posix_spawn_file_actions_adddup2(&acts, slave, STDOUT_FILENO); posix_spawn_file_actions_adddup2(&acts, slave, STDERR_FILENO); posix_spawn_file_actions_addclose(&acts, slave); posix_spawn_file_actions_addclose(&acts, *master); posix_spawnattr_t attrs; posix_spawnattr_init(&attrs); *err = posix_spawnattr_setflags(&attrs, flags); if (*err != 0) { goto done; } sigset_t signal_set; /* Reset all signal the child to their default behavior */ sigfillset(&signal_set); *err = posix_spawnattr_setsigdefault(&attrs, &signal_set); if (*err != 0) { goto done; } /* Reset the signal mask for all signals */ sigemptyset(&signal_set); *err = posix_spawnattr_setsigmask(&attrs, &signal_set); if (*err != 0) { goto done; } do *err = posix_spawn(pid, argv[0], &acts, &attrs, argv, env); while (*err == EINTR); done: posix_spawn_file_actions_destroy(&acts); posix_spawnattr_destroy(&attrs); for (; count > 0; count--) { close(low_fds[count]); } } #endif /** * Init */ NAN_MODULE_INIT(init) { Nan::HandleScope scope; Nan::Export(target, "fork", PtyFork); Nan::Export(target, "open", PtyOpen); Nan::Export(target, "resize", PtyResize); Nan::Export(target, "process", PtyGetProc); } NODE_MODULE(pty, init)