ERR_ALREADY_RUNNING is misleading if it's just a file permission problem

[Eric Myers]

The way the client determines whether another instance of itself is running is to try to open a lock file (via get_client_mutex() in lib/util.cpp). But this will fail not only if there is another client already running, but in the simpler case that the lock file cannot be created/written due to bad file permissions. It would be helpful to first test the file permissions and throw an error warning of that problem before checking the lock file itself.

For discussion and background see this thread: http://boinc.berkeley.edu/dev/forum_thread.php?id=4532 He figured it out, but it would have been easier with an explicit message pointing to a file permission problem.

[davea]

(In [20051]) - client: Unix: if can't create client lock file,

report ERR_OPEN rather than ERR_ALREADY_RUNNING fixes #970

[Nicolas]

Why not check errno to know why the client can't create lock file?

[Eric Myers]

Will this now give ERR_OPEN when in fact the problem is that another instance of the client daemon is running (the purpose of the lock file in the first place)?

[romw]

(In [20163]) - client: Unix: if can't create client lock file,

report ERR_OPEN rather than ERR_ALREADY_RUNNING fixes #970

lib/

util.cpp filesys.cpp