Erik Faye-Lund <kusmab...@gmail.com> writes:
> On Wed, Jan 23, 2013 at 4:32 PM, Thomas Rast <tr...@student.ethz.ch> wrote:
>> Erik Faye-Lund <kusmab...@gmail.com> writes:
>>> POSIX allows error codes
>>> to be generated other than those defined. From
>>> "Implementations may support additional errors not included in this
>>> list, *may generate errors included in this list under circumstances
>>> other than those described here*, or may contain extensions or
>>> limitations that prevent some errors from occurring."
>> That same page says, however:
>> For functions under the Threads option for which [EINTR] is not listed
>> as a possible error condition in this volume of IEEE Std 1003.1-2001,
>> an implementation shall not return an error code of [EINTR].
> Yes, but surely that's for pthreads functions, no? utime is not one of
> those functions...
Ah, my bad. In fact in
there is a paragraph "Signal Effects on Other Functions", which says
The most common behavior of an interrupted function after a
signal-catching function returns is for the interrupted function to
give an [EINTR] error unless the SA_RESTART flag is in effect for the
signal. However, there are a number of specific exceptions, including
sleep() and certain situations with read() and write().
The historical implementations of many functions defined by IEEE Std
1003.1-2001 are not interruptible[...]
Functions not mentioned explicitly as interruptible may be so on some
implementations, possibly as an extension where the function gives an
[EINTR] error. There are several functions (for example, getpid(),
getuid()) that are specified as never returning an error, which can
thus never be extended in this way.
If a signal-catching function returns while the SA_RESTART flag is in
effect, an interrupted function is restarted at the point it was
interrupted. Conforming applications cannot make assumptions about the
internal behavior of interrupted functions, even if the functions are
async-signal-safe. For example, suppose the read() function is
interrupted with SA_RESTART in effect, the signal-catching function
closes the file descriptor being read from and returns, and the read()
function is then restarted; in this case the application cannot assume
that the read() function will give an [EBADF] error, since read()
might have checked the file descriptor for validity before being
Taken together this should mean that the bug is in fact simply that the
calls do not *restart*. They are (like you say) allowed to return EINTR
despite not being specified to, *but* SA_RESTART should restart it.
Now, does that make it a lustre bug or a glibc bug? :-)
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