There is a general consensus that this change results in better
consistency between different operating systems and differently
tuned operating systems.
Note: this changes the width and meaning of the ipv6only field
of the ngx_listening_t structure. 3rd party modules that create
their own listening sockets might need fixing.
With previous code wildcard names were added to hash even if conflict
was detected. This resulted in identical names in hash and segfault
later in ngx_hash_wildcard_init().
If sending a DNS request fails with an error (e.g., when mistakenly trying
to send it to a local IP broadcast), such a request is not deleted if there
are clients waiting on it. However, it was still erroneously removed from
the queue. Later ngx_resolver_cleanup_tree() attempted to remove it from
the queue again that resulted in a NULL pointer dereference.
If we already had CNAME in resolver node (i.e. rn->cnlen and rn->u.cname
set), and got additional response with A record, it resulted in rn->cnlen
set and rn->u.cname overwritten by rn->u.addr (or rn->u.addrs), causing
segmentation fault later in ngx_resolver_free_node() on an attempt to free
overwritten rn->u.cname. The opposite (i.e. CNAME got after A) might cause
similar problems as well.
If name passed for resolution was { 0, NULL } (e.g. as a result
of name server returning CNAME pointing to ".") pointer wrapped
to (void *) -1 resulting in segmentation fault on an attempt to
dereference it.
Reported by Lanshun Zhou.
Integer overflow is undefined behaviour in C and this indeed caused
problems on Solaris/SPARC (at least in some cases). Fix is to
subtract unsigned integers instead, and then cast result to a signed
one, which is implementation-defined behaviour and used to work.
Strictly speaking, we should compare (unsigned) result with the maximum
value of the corresponding signed integer type instead, this will be
defined behaviour. This will require much more changes though, and
considered to be overkill for now.
Previous code incorrectly assumed that nodes with identical keys are linked
together. This might not be true after tree rebalance.
Patch by Lanshun Zhou.
The cycle->new_log.file may not be set before config parsing finished if
there are no error_log directive defined at global level. Fix is to
copy it after config parsing.
Patch by Roman Arutyunyan.
the last path component if "if_not_owner" parameter is used.
To prevent race condition we have to open a file before checking its owner and
there's no way to change access flags for already opened file descriptor, so
we disable symlinks for the last path component at all if flags allow creating
or truncating the file.
Solaris has AT_FDCWD defined to unsigned value, and comparison of a file
descriptor with it causes warnings in modern versions of gcc. Explicitly
cast AT_FDCWD to ngx_fd_t to resolve these warnings.
