Hi Bojan,
first of all the question is if the apr_file_t handle can be safely used
from different threads? e.g. is APR file wrapper thread safe? And I
don't think so! Or am I wrong? If it isn't thread safe the caller is
responsible for locking the involved operations in different threads!
If APR file wrappers should be thread safe, it has to use a mutex to
protect its state changes...
Regards,
Stefan
Bojan Smojver wrote:
We have effectively this code closing the file in apr_file_close():
---------------
static apr_status_t file_cleanup(apr_file_t *file, int is_child)
{
apr_status_t rv = APR_SUCCESS;
if (close(file->filedes) == 0) {
file->filedes = -1;
---------------
If someone calls apr_file_os_get() from another thread (whether they set
APR_FOPEN_XTHREAD or not), then may get a file->filedes which is an FD
of an already closed file. It gets worse - they may get an FD which was
reused by yet another thread. Quite dangerous.
I think it would be safer if we did this:
---------------
static apr_status_t file_cleanup(apr_file_t *file, int is_child)
{
apr_status_t rv = APR_SUCCESS;
int fd = file->filedes;
file->filedes = -1;
if (close(fd) == 0) {
[ ... ]
}
else {
[ ... ]
file->filedes = fd; /* restore, close() was not successful */
}
---------------
apr_socket_close() is similar.
Opinions?
