I found this in mod_perl but the issue can be demonstrated with Perl
alone and also without Perl. I'll start from the latter...
Attempting to open a file for append using the following flags:
APR_BUFFERED | APR_BINARY | APR_CREATE | APR_APPEND
will not work. The apr_file_open() function returns APR_EACCES. If the
following flags are used:
APR_BUFFERED | APR_BINARY | APR_CREATE | APR_WRITE | APR_APPEND
it works fine. In a vacuum this behavior is debatable. On the one
hand, APR_APPEND could be seen to imply APR_WRITE. On the other hand,
it might be argued that the first case is incomplete flag-wise.
In the context of Perl, however, particularly when using the APR PerlIO
filter, this becomes problematic. Perl uses special character sequences
which are converted to the proper flags down underneath the covers. So
in Perl '>' (write to a new file) converts properly but '>>' (append to
an existing file or create a new one if necessary) does not. There is
no message either, AFAIK, it just fails silently.
I'm attaching a couple of my test files. They demonstrate the problem
but don't show why it happens. I instrumented a copy of
file_io/unix/open.c to figure out what was happening. It fails in this
code:
if ((flag & APR_READ) && (flag & APR_WRITE)) {
oflags = O_RDWR;
}
else if (flag & APR_READ) {
oflags = O_RDONLY;
}
else if (flag & APR_WRITE) {
oflags = O_WRONLY;
}
else {
printf("fails here...\n");
return APR_EACCES;
}
I might suggest checking for APR_WRITE /or/ APR_APPEND, but there may be
some reason why it's done this way.
Has anyone else stumbled on this or am I doing something that breaks the
warranty? Is there a work-around in Perl?
--
Marc M. Adkins
Software Development Engineer
520 Pike Street, Suite 500
Seattle, WA 98101
P: 206-331-3508
F: 206.331.3695
E: madkins@marchex.com
Marchex Inc.
www.marchex.com
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--
Marc M. Adkins
Software Development Engineer
520 Pike Street, Suite 500
Seattle, WA 98101
P: 206-331-3508
F: 206.331.3695
E: madkins@marchex.com
Marchex Inc.
www.marchex.com
This e-mail message and any attachments are solely for
intended recipients, and may contain information that is
privileged and confidential. If you are not the intended
recipient, any dissemination, distribution or copying is
strictly prohibited. If you believe that you may have
received this message in error, please immediately notify
the sender by replying to this e-mail message.
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