hiredis bug?

[Richard Perini]

Hi,

I recently upgraded our hiredis client library from 0.10.1 to 1.1.0.
Following the upgrade, our processes that use the BRPOPLPUSH verb ceased
responding to SIGINT or SIGTERM, i.e. became uninterruptible while blocked
waiting for a new element on the list. The processes in question have been
running happily for years with the old driver.

I tracked this down to a change in the handling of the error return from recv()
(net.c redisNetRead() in the case of 1.1.0), versus similar handling for read()
in the old version (hiredis.c redisBufferRead() in 0.10.1).

The old version used to respond to EINTR by setting REDIS_ERR_IO with
__redisSetError(c,REDIS_ERR_IO,NULL) and return REDIS_ERR (-1).

The new version "ignores" EINTR by returning 0 from redisNetRead(), without
setting REDIS_ERR_IO. This in turn prevents redisGetReply() from ever
breaking out of the while(aux == NULL) loop.

I changed redisNetRead() to treat EINTR as it used to, by calling
__redisSetError(c, REDIS_ERR_IO, strerror(errno)); and returning -1, which
solves the problem for me.

Have I misunderstood something, or is this a bug? If so, is my fix the
correct way to rectify it?

Thank you,

--
Richard Perini

[Itamar Haber]

Hello Richard,

It would be good if you could also post this at the hiredis repo as an issue (https://github.com/redis/hiredis/issues/new) - it would probably get additional expert eyeballs there :)

Cheers,

Itamar