Enable Tor to load Torrc from <stdin> removing the need to write it to filesystem

This ticket is to enable Tor to load Torrc from remove the need to write it.

Tor wrapper libraries such as txtorcon from meejah, today write "torrc" in temporary directory when starting Tor.

It would be good if Tor could load Torrc from standard input, that way wrapper libraries starting Tor would be able to dynamically "feed" Tor a configuration file, without having to write to filesystem.

changed milestone to %Tor: 0.2.6.x-final

added component::core tor/tor milestone::Tor: 0.2.6.x-final nickm-patch priority::medium resolution::implemented status::closed tor torrc txtorconn type::enhancement unfrozen labels

The right syntax is probably something like "tor -f -", if we're following a unixy model.

Trac:
Keywords: torrc deleted, torrc lorax added
Milestone: N/A to Tor: 0.2.???

I also created this: https://github.com/meejah/txtorcon/issues/87

Covers the same use-case, but without modifying tor. I presume the use-case is "don't ever put the config data on a disk"?

@meejah yes

Preliminary version of the patch:

• https://github.com/rl1987/tor/commits/feature13865

I probably need to update src/test/test_cmdline_args.py to get this feature covered.

Trac:
Status: new to needs_review

Trac:
Cc: griffin to griffin, rl1987@sdf.lonestar.org

With #1976 (moved) and #5976 (moved) using TxTorCon applications such as GlobaLeaks would be able to use Tor without having to deal with FileSystem interaction!

Trac:
Milestone: Tor: 0.2.??? to Tor: 0.2.6.x-final

I agree that tests would be good. The code looks mostly plausible. A few suggestions:

• Make read_torrc_from_stdin const.

• Maybe instead of a trinary ... ? ... : ... expression, prefer an if...else ? If it's multiline like that it probaby isn't adding to clarity.

• The strncmp... should be a strcmp. You're checking whether the value is exactly -, not whether it starts with -.

• How about you replace the body of load_torrc_from_stdin with a call to read_file_to_str_until_eof(STDIN_FILENO, (1u<<24), NULL) ?

Trac:
Status: needs_review to needs_revision

Looks like rl1987 fixed the above issues!

Trac:
Status: needs_revision to needs_review
Keywords: torrc lorax deleted, torrc nickm-patch unfrozen added

Looks good now; merging; thanks!

Trac:
Status: needs_review to closed
Resolution: N/A to implemented

FYI i just opened #14899 (moved) to "Enable Tor to work without using filesystem for cached files" that, together with #6411 (moved) would complete the ability to have a fully filesystem-free Tor process managed by a third party application controller.

This was a great addition - thanks rl1987! Stem now takes advantage of this transparently.

closed

mentioned in issue #14899 (moved)

moved to tpo/core/tor#13865 (closed)

mentioned in issue tpo/core/tor#14899 (closed)