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spawn's stdio can result in stderr being closed in child #862
Description
var cp = require('child_process');
var fs = require('fs');
if (process.env.CHILD) {
console.error('ERROR');
return;
}
// open child stdout and stderr on our stderr
var options = {
stdio: [0, 2, 2],
env: { CHILD: true },
};
var c = cp.spawn(process.execPath, [__filename], options);
Result: 'ERROR' is not printed.
Excerpt from strace:
[pid 11780] write(2, "ERROR\n", 6) = -1 EBADF (Bad file descriptor)
[pid 11780] write(2, "ERROR\n", 6) = -1 EBADF (Bad file descriptor)
[pid 11780] epoll_ctl(4, EPOLL_CTL_DEL, 2, {EPOLLWRNORM|EPOLLHUP|EPOLLRDHUP|EPOLLET|0x242e0000, {u32=32767, u64=47321597480042495}}) = -1 ENOENT (No such file or directory)
[pid 11780] write(2, "events.js:141\n throw er; //"..., 244) = -1 EBADF (Bad file descriptor)
[pid 11780] exit_group(1) = ?
[pid 11785] +++ exited with 1 +++
This likely a bug in libuv, but reporting it here because that's where I saw it.
Affects node v0.10 and io.js.
/cc @saghul @bnoordhuis I think we tried to fix a variant of this a year or so ago.
Activity
saghul commentedon Feb 17, 2015
I believe that's still not fixed. This is the closest open issue I could find: joyent/libuv#923
bnoordhuis commentedon Feb 17, 2015
I think this asks for a two-pronged approach: libuv probably has a bug or two that need to be addressed but io.js could reopen fds 0-2 as /dev/null if they aren't valid file descriptors.
vkurchatkin commentedon Feb 17, 2015
@bnoordhuis can you also comment on #831 ?
sam-github commentedon Feb 18, 2015
Opening fd 2 on /dev/null would avoid the EBADF, and probably is a good idea, so fd 2 doesn't become some random open file, but wouldn't avoid the underlying problem, that
console.error()never prints, because stderr is gone.I dug up the last time I saw this:
test: do not trigger node bug with fd mapping
sam-github commentedon Feb 24, 2015
@saghul I think I've fixed this, as well as some related bugs. I'm putting together some node tests, then I'll PR the fix to libuv.
saghul commentedon Feb 24, 2015
Great! Thanks Sam.
On Feb 24, 2015 6:57 PM, "Sam Roberts" notifications@github.com wrote:
unix: don't close the fds we just setup
unix: don't close the fds we just setup
unix: don't close the fds we just setup
unix: don't close the fds we just setup
deps: update libuv to 1.5.0
bnoordhuis commentedon May 6, 2015
Should be fixed by 04cc03b. Closing, holler if I should reopen it.
deps: update libuv to 1.5.0
leth commentedon Sep 7, 2016
I'm seeing a failure like this frequently from
npm installunder node 6.4.0.