int flags = fcntl(fd, F_GETFL, 0);

int r = fcntl(fd, F_SETFL, flags | O_NONBLOCK);

if (r != 0) {

perror("SetNonBlocking()");

}

return r;

int flags = fcntl(fd, F_GETFD, 0);

int r = fcntl(fd, F_SETFD, flags | FD_CLOEXEC);

if (r != 0) {

perror("SetCloseOnExec()");

}

return r;

int flags = fcntl(fd, F_GETFL, 0);

// blocking

int r = fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);

flags = fcntl(fd, F_GETFD, 0);

// unset the CLOEXEC

fcntl(fd, F_SETFD, flags & ~FD_CLOEXEC);

return r;

HandleScope scope;

Local<FunctionTemplate> t = FunctionTemplate::New(ChildProcess::New);

t->InstanceTemplate()->SetInternalFieldCount(1);

t->SetClassName(String::NewSymbol("ChildProcess"));

pid_symbol = NODE_PSYMBOL("pid");

onexit_symbol = NODE_PSYMBOL("onexit");

NODE_SET_PROTOTYPE_METHOD(t, "spawn", ChildProcess::Spawn);

NODE_SET_PROTOTYPE_METHOD(t, "kill", ChildProcess::Kill);

target->Set(String::NewSymbol("ChildProcess"), t->GetFunction());

HandleScope scope;

ChildProcess *p = new ChildProcess();

p->Wrap(args.Holder());

return args.This();

HandleScope scope;

if (args.Length() < 3 ||

!args[0]->IsString() ||

!args[1]->IsArray() ||

!args[2]->IsString() ||

!args[3]->IsArray() ||

!args[4]->IsArray() ||

!args[5]->IsBoolean() ||

!(args[6]->IsInt32() || args[6]->IsString()) ||

!(args[7]->IsInt32() || args[7]->IsString())) {

return ThrowException(Exception::Error(String::New("Bad argument.")));

}

ChildProcess *child = ObjectWrap::Unwrap<ChildProcess>(args.Holder());

String::Utf8Value file(args[0]->ToString());

int i;

// Copy second argument args[1] into a c-string array called argv.

// The array must be null terminated, and the first element must be

// the name of the executable -- hence the complication.

Local<Array> argv_handle = Local<Array>::Cast(args[1]);

int argc = argv_handle->Length();

int argv_length = argc + 1 + 1;

char **argv = new char*[argv_length]; // heap allocated to detect errors

argv[0] = strdup(*file); // + 1 for file

argv[argv_length-1] = NULL; // + 1 for NULL;

for (i = 0; i < argc; i++) {

String::Utf8Value arg(argv_handle->Get(Integer::New(i))->ToString());

argv[i+1] = strdup(*arg);

}

// Copy third argument, args[2], into a c-string called cwd.

String::Utf8Value arg(args[2]->ToString());

char *cwd = strdup(*arg);

// Copy fourth argument, args[3], into a c-string array called env.

Local<Array> env_handle = Local<Array>::Cast(args[3]);

int envc = env_handle->Length();

char **env = new char*[envc + 1]; // heap allocated to detect errors

env[envc] = NULL;

for (int i = 0; i < envc; i++) {

String::Utf8Value pair(env_handle->Get(Integer::New(i))->ToString());

env[i] = strdup(*pair);

}

int custom_fds[3] = { -1, -1, -1 };

if (args[4]->IsArray()) {

// Set the custom file descriptor values (if any) for the child process

Local<Array> custom_fds_handle = Local<Array>::Cast(args[4]);

int custom_fds_len = custom_fds_handle->Length();

// Bound by 3.

if (custom_fds_len > 3) {

custom_fds_len = 3;

}

for (int i = 0; i < custom_fds_len; i++) {

if (custom_fds_handle->Get(i)->IsUndefined()) continue;

Local<Integer> fd = custom_fds_handle->Get(i)->ToInteger();

custom_fds[i] = fd->Value();

}

}

int do_setsid = false;

if (args[5]->IsBoolean()) {

do_setsid = args[5]->BooleanValue();

}

int fds[3];

char *custom_uname = NULL;

int custom_uid = -1;

if (args[6]->IsNumber()) {

custom_uid = args[6]->Int32Value();

} else if (args[6]->IsString()) {

String::Utf8Value pwnam(args[6]->ToString());

custom_uname = (char *)calloc(sizeof(char), pwnam.length() + 1);

strncpy(custom_uname, *pwnam, pwnam.length() + 1);

} else {

return ThrowException(Exception::Error(

String::New("setuid argument must be a number or a string")));

}

char *custom_gname = NULL;

int custom_gid = -1;

if (args[7]->IsNumber()) {

custom_gid = args[7]->Int32Value();

} else if (args[7]->IsString()) {

String::Utf8Value grnam(args[7]->ToString());

custom_gname = (char *)calloc(sizeof(char), grnam.length() + 1);

strncpy(custom_gname, *grnam, grnam.length() + 1);

} else {

return ThrowException(Exception::Error(

String::New("setgid argument must be a number or a string")));

}

int channel_fd = -1;

int r = child->Spawn(argv[0],

argv,

cwd,

env,

fds,

custom_fds,

do_setsid,

custom_uid,

custom_uname,

custom_gid,

custom_gname,

&channel_fd);

if (custom_uname != NULL) free(custom_uname);

if (custom_gname != NULL) free(custom_gname);

for (i = 0; i < argv_length; i++) free(argv[i]);

delete [] argv;

free(cwd);

for (i = 0; i < envc; i++) free(env[i]);

delete [] env;

if (r != 0) {

return ThrowException(Exception::Error(String::New("Error spawning")));

}

Local<Array> a = Array::New(channel_fd >= 0 ? 4 : 3);

assert(fds[0] >= 0);

a->Set(0, Integer::New(fds[0])); // stdin

assert(fds[1] >= 0);

a->Set(1, Integer::New(fds[1])); // stdout

assert(fds[2] >= 0);

a->Set(2, Integer::New(fds[2])); // stderr

if (channel_fd >= 0) {

a->Set(3, Integer::New(channel_fd));

}

return scope.Close(a);

HandleScope scope;

ChildProcess *child = ObjectWrap::Unwrap<ChildProcess>(args.Holder());

assert(child);

if (child->pid_ < 1) {

// nothing to do

return False();

}

int sig = SIGTERM;

if (args.Length() > 0) {

if (args[0]->IsNumber()) {

sig = args[0]->Int32Value();

} else {

return ThrowException(Exception::TypeError(String::New("Bad argument.")));

}

}

if (child->Kill(sig) != 0) {

return ThrowException(ErrnoException(errno, "Kill"));

}

return True();

if (ev_is_active(&child_watcher_)) {

ev_child_stop(EV_DEFAULT_UC_ &child_watcher_);

Unref();

}

// Don't kill the PID here. We want to allow for killing the parent

// process and reparenting to initd. This is perhaps not going the best

// technique for daemonizing, but I don't want to rule it out.

pid_ = -1;

char *const args[],

const char *cwd,

char **env,

int stdio_fds[3],

int custom_fds[3],

bool do_setsid,

int custom_uid,

char *custom_uname,

int custom_gid,

char *custom_gname,

int* channel) {

HandleScope scope;

assert(pid_ == -1);

assert(!ev_is_active(&child_watcher_));

int stdin_pipe[2], stdout_pipe[2], stderr_pipe[2];

/* An implementation of popen(), basically */

if ((custom_fds[0] == -1 && pipe(stdin_pipe) < 0) ||

(custom_fds[1] == -1 && pipe(stdout_pipe) < 0) ||

(custom_fds[2] == -1 && pipe(stderr_pipe) < 0)) {

perror("pipe()");

return -1;

}

// Set the close-on-exec FD flag

if (custom_fds[0] == -1) {

SetCloseOnExec(stdin_pipe[0]);

SetCloseOnExec(stdin_pipe[1]);

}

if (custom_fds[1] == -1) {

SetCloseOnExec(stdout_pipe[0]);

SetCloseOnExec(stdout_pipe[1]);

}

if (custom_fds[2] == -1) {

SetCloseOnExec(stderr_pipe[0]);

SetCloseOnExec(stderr_pipe[1]);

}

// The channel will be used by js-land "fork()" for a little JSON channel.

// The pointer is used to pass one end of the socket pair back to the

// parent.

// channel_fds[0] is for the parent

// channel_fds[1] is for the child

int channel_fds[2] = { -1, -1 };

#define NODE_CHANNEL_FD "NODE_CHANNEL_FD"

for (int i = 0; env[i]; i++) {

if (!strncmp(env[i], NODE_CHANNEL_FD, sizeof NODE_CHANNEL_FD - 1)) {

if (socketpair(AF_UNIX, SOCK_STREAM, 0, channel_fds)) {

perror("socketpair()");

return -1;

}

assert(channel_fds[0] >= 0 && channel_fds[1] >= 0);

SetNonBlocking(channel_fds[0]);

SetNonBlocking(channel_fds[1]);

// Write over the FILLMEIN :D

sprintf(env[i], NODE_CHANNEL_FD "=%d", channel_fds[1]);

}

}

// Save environ in the case that we get it clobbered

// by the child process.

char **save_our_env = environ;

switch (pid_ = fork()) {

case -1: // Error.

Stop();

return -4;

case 0: // Child.

if (do_setsid && setsid() < 0) {

perror("setsid");

_exit(127);

}

if (custom_fds[0] == -1) {

close(stdin_pipe[1]); // close write end

dup2(stdin_pipe[0], STDIN_FILENO);

} else {

ResetFlags(custom_fds[0]);

dup2(custom_fds[0], STDIN_FILENO);

}

if (custom_fds[1] == -1) {

close(stdout_pipe[0]); // close read end

dup2(stdout_pipe[1], STDOUT_FILENO);

} else {

ResetFlags(custom_fds[1]);

dup2(custom_fds[1], STDOUT_FILENO);

}

if (custom_fds[2] == -1) {

close(stderr_pipe[0]); // close read end

dup2(stderr_pipe[1], STDERR_FILENO);

} else {

ResetFlags(custom_fds[2]);

dup2(custom_fds[2], STDERR_FILENO);

}

if (strlen(cwd) && chdir(cwd)) {

perror("chdir()");

_exit(127);

}

static char buf[PATH_MAX + 1];

int gid = -1;

if (custom_gid != -1) {

gid = custom_gid;

} else if (custom_gname != NULL) {

struct group grp, *grpp = NULL;

int err = getgrnam_r(custom_gname,

&grp,

buf,

PATH_MAX + 1,

&grpp);

if (err || grpp == NULL) {

perror("getgrnam_r()");

_exit(127);

}

gid = grpp->gr_gid;

}

int uid = -1;

if (custom_uid != -1) {

uid = custom_uid;

} else if (custom_uname != NULL) {

struct passwd pwd, *pwdp = NULL;

int err = getpwnam_r(custom_uname,

&pwd,

buf,

PATH_MAX + 1,

&pwdp);

if (err || pwdp == NULL) {

perror("getpwnam_r()");

_exit(127);

}

uid = pwdp->pw_uid;

}

if (gid != -1 && setgid(gid)) {

perror("setgid()");

_exit(127);

}

if (uid != -1 && setuid(uid)) {

perror("setuid()");

_exit(127);

}

// Close the parent's end of the channel.

if (channel_fds[0] >= 0) {

close(channel_fds[0]);

channel_fds[0] = -1;

}

environ = env;

execvp(file, args);

perror("execvp()");

_exit(127);

}

// Parent.

// Restore environment.

environ = save_our_env;

ev_child_set(&child_watcher_, pid_, 0);

ev_child_start(EV_DEFAULT_UC_ &child_watcher_);

Ref();

handle_->Set(pid_symbol, Integer::New(pid_));

if (custom_fds[0] == -1) {

close(stdin_pipe[0]);

stdio_fds[0] = stdin_pipe[1];

SetNonBlocking(stdin_pipe[1]);

} else {

stdio_fds[0] = custom_fds[0];

}

if (custom_fds[1] == -1) {

close(stdout_pipe[1]);

stdio_fds[1] = stdout_pipe[0];

SetNonBlocking(stdout_pipe[0]);

} else {

stdio_fds[1] = custom_fds[1];

}

if (custom_fds[2] == -1) {

close(stderr_pipe[1]);

stdio_fds[2] = stderr_pipe[0];

SetNonBlocking(stderr_pipe[0]);

} else {

stdio_fds[2] = custom_fds[2];

}

// Close the child's end of the channel.

if (channel_fds[1] >= 0) {

close(channel_fds[1]);

channel_fds[1] = -1;

assert(channel_fds[0] >= 0);

assert(channel);

*channel = channel_fds[0];

} else {

*channel = -1;

}

return 0;

HandleScope scope;

pid_ = -1;

Stop();

handle_->Set(pid_symbol, Null());

Local<Value> onexit_v = handle_->Get(onexit_symbol);

assert(onexit_v->IsFunction());

Local<Function> onexit = Local<Function>::Cast(onexit_v);

TryCatch try_catch;

Local<Value> argv[2];

if (WIFEXITED(status)) {

argv[0] = Integer::New(WEXITSTATUS(status));

} else {

argv[0] = Local<Value>::New(Null());

}

if (WIFSIGNALED(status)) {

argv[1] = String::NewSymbol(signo_string(WTERMSIG(status)));

} else {

argv[1] = Local<Value>::New(Null());

}

onexit->Call(handle_, 2, argv);

if (try_catch.HasCaught()) {

FatalException(try_catch);

}