Bugs item #2800519, was opened at 2009-06-03 15:55
Message generated for change (Settings changed) made by bagder
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Category: misc
Group: None
Status: Open
>Resolution: Fixed
Priority: 5
Private: No
Submitted By: Nobody/Anonymous (nobody)
Assigned to: Daniel Stenberg (bagder)
Summary: libssh2 library is not thread safe
Initial Comment:
By default, there is no "-D_REENTRANT" flag passed to the C preprocessor (nor any -mt (Sun Studio) or -pthreads (gcc) option to the C compiler).
Note: I'm using libssh2 on Solaris 9/10, using Sun Studio 12.
Referencing errno in many pieces of code makes the whole library not thread safe (libssh2_session_startup() for example). There are many EAGAIN errors that are now thrown internally (because of new non-blocking sockets in 1.1), but unfortunately, the errno value is not correctly accessed, leading to undefined behaviour. This can be "easily" reproduced using something like (compiled in a thread safe manner):
Th.1: set errno
Th.1: detach thread 2
Th.2: establish an SSH connection. libssh2_session_startup() will usually fail.
I've passed CPPFLAGS="-D_REENTRANT" to the configure script, and things seem now to be OK.
Miscellaneous defects of the "configure" script:
- Specifying LDFLAGS="-mt -pthreads" does not pass these options to the ld linker.
- Specifying --disable-debug still compiles with "-g".
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>Comment By: Daniel Stenberg (bagder)
Date: 2009-06-04 20:26
Message:
I've now committed a fix for this in the git repo. It'd be great if you
tried it.
The fix will be included in the June 5 and later snapshots from =>
http://libssh2.haxx.se/snapshots.html
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Comment By: Gaëtan Buchetet (p82420)
Date: 2009-06-04 11:13
Message:
Hello,
Sorry, but I'm not really confident with configure.in, m4 macros and all
that stuff.
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Comment By: Daniel Stenberg (bagder)
Date: 2009-06-04 08:55
Message:
The configure script obviously needs to check for _REENTRANT. I'm confident
we can get some inspiration and code from here:
http://curl.haxx.se/lxr/source/m4/curl-reentrant.m4#L390
You able to provide a patch?
----------------------------------------------------------------------
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https://sourceforge.net/tracker/?func=detail&atid=703942&aid=2800519&group_id=125852
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Received on 2009-06-04