fs.writeFile and fs.writeFileSync ignores options.mode and always writes with permission '644'

[kaizhu256]

bug reproduced on node v0.10 and v0.12, on both linux and mac with the following code:

var fs = require('fs');
fs.writeFileSync('a00.txt', 'hello', { mode: '666' });
console.log(fs.statSync('a00.txt').mode.toString(8));
// output: 100644

[thefourtheye]

Just tried with v0.12.7 and I got 100666

[kaizhu256]

here's screenshot on my macbook air (late 2014, running mavericks with homebrew node v0.12.7)

[kaizhu256]

another screenshot running debian unstable on linode

[jfmercer]

I've gotten some strange results. It works when I use '0755', but not when I use '0666'. Because octals are forbidden in strict mode, I've passed them as strings to parseInt().

'0755':

'0666':

[targos]

I can reproduce the results in the OP with v0.12.7. (OSX 10.10)

[jasnell]

Yes, I'm able to reproduce this. The documentation even states that the default mode is 666, but when calling writeFileSync without the mode param, the mode will still be set as 644. /cc @joyent/node-tsc

[jfmercer]

My workaround was to use fs.chmod, e.g., fs.chmod('file.txt', '0755');, after the file had been created with fs.writeFile. Note that I had to pass the octal number as a string because JS strict mode prohibits the use of octal numbers, but not parsable octal strings.

Still, I'd like fs.writeFile and fs.writeFileSync work as described in the documentation.

[targos]

I found that this is in fact not an issue, but just how UNIX file permissions are handled.
Whatever mode you pass to writeFile, it will be combined with the umask during the open system call.

You can change the umask with process.umask(newValue). If you set it to 0, the mode will be set exactly to the value you pass to the fs methods.

See nodejs/node#2249 and nodejs/node#1104 for more discussion about this problem.

[jasnell]

Yeah, I suspected that was the case but hadn't investigated. Unfortunately the documentation is not clear on that at all. I'm going to tag this as a documentation fix. If you're up to it, a PR fixing up the docs is always welcome ;-)