[jira] [Updated] (PROTON-1292) errno not thread-safe on Solaris

["Justin Ross (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/PROTON-1292?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Justin Ross updated PROTON-1292:
--------------------------------
    Labels: solaris  (was: )

> errno not thread-safe on Solaris
> --------------------------------
>
>                 Key: PROTON-1292
>                 URL: https://issues.apache.org/jira/browse/PROTON-1292
>             Project: Qpid Proton
>          Issue Type: Bug
>          Components: proton-c
>    Affects Versions: 0.12.2, 0.13.0
>            Reporter: Adel Boutros
>            Assignee: Andrew Stitcher
>              Labels: solaris
>             Fix For: 0.16.0
>
>
> For some time, we were having random errors on Solaris with proton-c where we would get a transport error "proton:io connect: Error 0". We were finally able to reproduce it in a multi-threading environment. It turns out some C/C++ system calls such as opening sockets will set the value of "errno" and some parts of proton-c code you rely on the value of errno to determine if the operation was successful or not[1].
> The issue is that errno is not thread safe[2] and as a consequence if by the time Thread A was checking the value of errno, Thread B has set it to something else, the check will fail.
> We resolved it by compiling Proton with "-D_REENTRANT" which makes errno thread local variable.
> Please note we only got this error on Solaris because on Linux setting "-lpthread" implies "-D_REENTRANT flag" according to stackoverflow[2].
> Do you think this flag could be set by default in the CMakeList of proton to avoid others having the same issue?
> On Solaris:
> /usr/include/errno.h
> #if defined(_REENTRANT) || defined(_TS_ERRNO) || _POSIX_C_SOURCE - 0 >= 199506L
> extern int *___errno();
> #define errno (*(___errno()))
> #else
> extern int errno;
> /* ANSI C++ requires that errno be a macro */
> #if __cplusplus >= 199711L
> #define errno errno
> #endif
> #endif  /* defined(_REENTRANT) || defined(_TS_ERRNO) */
> PS: The code is still the same on 0.14.0. So the error could happen there as well I guess.
> [1]: https://github.com/apache/qpid-proton/blob/0.12.2/proton-c/src/posix/io.c (line 187-188)
> [2]: http://stackoverflow.com/questions/1694164/is-errno-thread-safe
> [3]: http://stackoverflow.com/questions/875789/gcc-do-i-need-d-reentrant-with-pthreads 



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