Also disable the semantic patch as the code needs tweaks here and there because
some destroy functions might not destroy the object and return early if the
object is still in use.
This commits removes superfluous checks when using the isc_refcount API.
Examples of superfluous checks:
1. The isc_refcount_decrement function ensures there was not underflow,
so this check is superfluous:
INSIST(isc_refcount_decrement(&r) > 0);
2 .The isc_refcount_destroy() includes check whether the counter
is zero, therefore this is superfluous:
INSIST(isc_refcount_decrement(&r) == 1 && isc_refcount_destroy(&r));
glibc 2.30 deprecated the <sys/sysctl.h> header [1]. However, that
header is still used on other Unix-like systems, so only prevent it from
being used on Linux, in order to prevent compiler warnings from being
triggered.
[1] https://sourceware.org/ml/libc-alpha/2019-08/msg00029.html
isc_event_allocate() calls isc_mem_get() to allocate the event structure. As
isc_mem_get() cannot fail softly (e.g. it never returns NULL), the
isc_event_allocate() cannot return NULL, hence we remove the (ret == NULL)
handling blocks using the semantic patch from the previous commit.
Previously isc_thread_join() would return ISC_R_UNEXPECTED on a failure to
create new thread. All such occurences were caught and wrapped into assert
function at higher level. The function was simplified to assert directly in the
isc_thread_join() function and all caller level assertions were removed.
Previously isc_thread_create() would return ISC_R_UNEXPECTED on a failure to
create new thread. All such occurences were caught and wrapped into assert
function at higher level. The function was simplified to assert directly in the
isc_thread_create() function and all caller level assertions were removed.
Using isc_mem_put(mctx, ...) + isc_mem_detach(mctx) required juggling with the
local variables when mctx was part of the freed object. The isc_mem_putanddetach
function can handle this case internally, but it wasn't used everywhere. This
commit apply the semantic patching plus bit of manual work to replace all such
occurrences with proper usage of isc_mem_putanddetach().
The SO_BSDCOMPAT socket option is no-op since Linux 2.4, see the manpage:
SO_BSDCOMPAT
Enable BSD bug-to-bug compatibility. This is used by the UDP protocol
module in Linux 2.0 and 2.2. If enabled, ICMP errors received for a UDP
socket will not be passed to the user program. In later kernel
versions, support for this option has been phased out: Linux 2.4
silently ignores it, and Linux 2.6 generates a kernel warning (printk())
if a program uses this option. Linux 2.0 also enabled BSD bug-to-bug
compatibility options (random header changing, skipping of the broadcast
flag) for raw sockets with this option, but that was removed in Linux
2.2.
The json-c have previously leaked into the global namespace leading
to forced -I<include_path> for every compilation unit using isc/xml.h
header. This MR fixes the usage making the caller object opaque.
The libxml2 have previously leaked into the global namespace leading
to forced -I<include_path> for every compilation unit using isc/xml.h
header. This MR fixes the usage making the caller object opaque.
There's a small possibility of race between udp dispatcher and
socket code - socket code can still hold internal reference to a
socket while dispatcher calls isc_socket_open, which can cause
an assertion failure. Fix it by relaxing the assertion test, and
instead simply locking the socket in isc_socket_open.
Each network thread holds an array of locks, indexed by a hash
of fd. When we accept a connection we hold a lock in accepting thread.
We then generate the thread number and lock bucket for the new
connection socket - if we hit the same thread and lock bucket as
accepting socket we get a deadlock. Avoid this by checking if we're
in the same thread/lock bucket and not locking in this case.
This work cleans up the API which includes couple of things:
1. Make the isc_appctx_t type fully opaque
2. Protect all access to the isc_app_t members via stdatomics
3. sigwait() is part of POSIX.1, remove dead non-sigwait code
4. Remove unused code: isc_appctx_set{taskmgr,sockmgr,timermgr}
Mutexes are slower if they're in the same cache line. Since
fd's come in herds, and usually our listen sockets will have nearby
fd numbers, we mangle fdlocks so that the locks are further away.
