fix #571: accessTokens.json is 0644

[yugangw-msft]

@ahmetalpbalkan , i do it on newly created file, just in case people might have tweaked to other permissions they prefer.

[ahmetb]

@yugangw-msft doesn't python have an open(2) equivalent call where you w+ and get to specify chmod mode?

[ahmetb]

I see os.open will do the job for you

print os.open.__doc__
open(filename, flag [, mode=0777]) -> fd

Open a file (for low level IO).

I don't find the current patch with new_file clean.

[ahmetb]

doesn't this always remove the contents you just wrote one line above? if you need file to be truncated when you open it, you can use os.O_TRUNC.

[yugangw-msft]

no, this is working code. and a little surprising to me. Checkout this SO thread

[yugangw-msft]

Using the flag appears do the same, but more consistent, so i take your suggestion.
Note, barring the effect of umask, the whole change will always update the file mode, even a file which a user has specifically tweaked the permission. i thought it would be an issue, but i don't have strong opinions

[ahmetb]

even a file which a user has specifically tweaked the permission.

I think this is going to be fine. on the flip side, if users make an error and make their files too open, you'll be fixing it for them.

for instance, programs like /usr/bin/ssh don't work with private key files if they are readable by other users as well.