It is currently used from master process on abnormal worker termination to
unlock accept mutex (unlocking of accept mutex was broken in 1.0.2). It is
expected to be used in the future to unlock other mutexes as well.
Shared mutex code was rewritten to make this possible in a safe way, i.e.
with a check if lock was actually held by the exited process. We again use
pid to lock mutex, and use separate atomic variable for a count of processes
waiting in sem_wait().
Stale write event may happen if epoll_wait() reported both read and write
events, and processing of the read event closed descriptor.
Patch by Yichun Zhang (agentzh).
If possible we now just extend already present file buffer in p->out chain
instead of keeping ngx_buf_t for each buffer we've flushed to disk. This
saves about 120 bytes of memory per buffer flushed to disk, and resolves
high CPU usage observed in edge cases (due to coalescing these buffers on
send).
1. In ngx_event_pipe_write_chain_to_temp_file() make sure to fully write
all shadow buffers up to last_shadow. With this change recycled buffers
cannot appear in p->out anymore. This also fixes segmentation faults
observed due to ngx_event_pipe_write_chain_to_temp() not freeing any
raw buffers while still returning NGX_OK.
2. In ngx_event_pipe_write_to_downstream() we now properly check for busy
size as a size of buffers, not a size of data in these buffers. This
fixes situations where all available buffers became busy (including
segmentation faults due to this).
3. The ngx_event_pipe_free_shadow_raw_buf() function is dropped. It's
incorrect and not needed.
If client closed connection in ngx_event_pipe_write_to_downstream(), buffers
in the "out" chain were lost. This caused cpu hog if all available buffers
were in the "out" chain. Fix is to call ngx_chain_update_chains() before
checking return code of output filter to avoid loosing buffers in the "out"
chain.
Note that this situation (all available buffers in the "out" chain) isn't
normal, it should be prevented by busy buffers limit. Though right now it
may happen with complex protocols like fastcgi. This should be addressed
separately.
The default value is 32 AIO simultaneous requests per worker. Previously
they were hardcoded to 1024, and it was too large, since Linux allocated
them early on io_setup(), but not on request itself. So with default value
of /proc/sys/fs/aio-max-nr equal to 65536 only 64 worker processes could
be run simultaneously. 32 AIO requests are enough for modern disks even if
server runs only 1 worker.
syscall(2) uses usual libc convention, it returns -1 on error and
sets errno. Obsolete _syscall(2) returns negative value of error.
Thanks to Hagai Avrahami.
As long as ngx_event_pipe() has more data read from upstream than specified
in p->length it's passed to input filter even if buffer isn't yet full. This
allows to process data with known length without relying on connection close
to signal data end.
By default p->length is set to -1 in upstream module, i.e. end of data is
indicated by connection close. To set it from per-protocol handlers upstream
input_filter_init() now called in buffered mode (as well as in
unbuffered mode).
The ngx_chain_update_chains() needs pool to free chain links used for buffers
with non-matching tags. Providing one helps to reduce memory consumption
for long-lived requests.
Setting read->eof to 0 seems to be just a typo. It appeared in
nginx-0.0.1-2003-10-28-18:45:41 import (r164), while identical code in
ngx_recv.c introduced in the same import do actually set read->eof to 1.
Failure to set read->eof to 1 results in EOF not being generally detectable
from connection flags. On the other hand, kqueue won't report any read
events on such a connection since we use EV_CLEAR. This resulted in read
timeouts if such connection was cached and used for another request.
If connection has unsent alerts, SSL_shutdown() tries to send them even
if SSL_set_shutdown(SSL_RECEIVED_SHUTDOWN|SSL_SENT_SHUTDOWN) was used.
This can be prevented by SSL_set_quiet_shutdown(). SSL_set_shutdown()
is required nevertheless to preserve session.
enabled in any server. The previous r1033 does not help when unused zone
becomes used after reconfiguration, so it is backed out.
The initial thought was to make SSL modules independed from SSL implementation
and to keep OpenSSL code dependance as much as in separate files.
and is shared among all hosts instead of pregenerating for every HTTPS host
on configuraiton phase. This decreases start time for configuration with
large number of HTTPS hosts.
this fixes OpenSSL "bad write retry" error, when
*) nginx passed a single buf greater than our buffer (say 32K) to OpenSSL,
*) OpenSSL returns SSL_ERROR_WANT_WRITE,
*) after some time nginx has to send a new data,
*) so there are at least two bufs nginx does pass them directly to OpenSSL,
*) but copies the first buf part to buffer, and sends the buffer to OpenSSL.
*) because the data length is lesser than it was in previous SSL_write():
16K < 32K, OpenSSL returns SSL_R_BAD_WRITE_RETRY.
*) test ssl_client_certificate for ssl_verify_client
*) $ssl_client_cert adds TAB before each line except first one
*) $ssl_client_raw_cert contains certificate as is
