nginx 0.3.8 *) Security: nginx now checks URI got from a backend in "X-Accel-Redirect" header line or in SSI file for the "/../" paths and zeroes. *) Change: nginx now does not treat the empty user name in the "Authorization" header line as valid one. *) Feature: the "ssl_session_timeout" directives of the ngx_http_ssl_module and ngx_imap_ssl_module. *) Feature: the "auth_http_header" directive of the ngx_imap_auth_http_module. *) Feature: the "add_header" directive. *) Feature: the ngx_http_realip_module. *) Feature: the new variables to use in the "log_format" directive: $bytes_sent, $apache_bytes_sent, $status, $time_gmt, $uri, $request_time, $request_length, $upstream_status, $upstream_response_time, $gzip_ratio, $uid_got, $uid_set, $connection, $pipe, and $msec. The parameters in the "%name" form will be canceled soon. *) Change: now the false variable values in the "if" directive are the empty string "" and string starting with "0". *) Bugfix: while using proxied or FastCGI-server nginx may leave connections and temporary files with client requests in open state. *) Bugfix: the worker processes did not flush the buffered logs on graceful exit. *) Bugfix: if the request URI was changes by the "rewrite" directive and the request was proxied in location given by regular expression, then the incorrect request was transferred to backend; bug appeared in 0.2.6. *) Bugfix: the "expires" directive did not remove the previous "Expires" header. *) Bugfix: nginx may stop to accept requests if the "rtsig" method and several worker processes were used. *) Bugfix: the "\"" and "\'" escape symbols were incorrectly handled in SSI commands. *) Bugfix: if the response was ended just after the SSI command and gzipping was used, then the response did not transferred complete or did not transferred at all.

/*
 * Copyright (C) Igor Sysoev
 */


#if (NGX_SMP)
#define NGX_SMP_LOCK  "lock;"
#else
#define NGX_SMP_LOCK
#endif


/*
 * "cmpxchgq  r, [m]":
 *
 *     if (rax == [m]) {
 *         zf = 1;
 *         [m] = r;
 *     } else {
 *         zf = 0;
 *         rax = [m];
 *     }
 *
 *
 * The "r" is any register, %rax (%r0) - %r16.
 * The "=a" and "a" are the %rax register.  Although we can return result
 * in any register, we use %rax because it is used in cmpxchgq anyway.
 * The "cc" means that flags were changed.
 */

static ngx_inline ngx_atomic_uint_t
ngx_atomic_cmp_set(ngx_atomic_t *lock, ngx_atomic_uint_t old,
    ngx_atomic_uint_t set)
{   
    ngx_atomic_uint_t  res;

    __asm__ volatile (

         NGX_SMP_LOCK
    "    cmpxchgq  %3, %1;   "
    "    setz      %b0;      "
    "    movzbq    %b0, %0;  "

    : "=a" (res) : "m" (*lock), "a" (old), "r" (set) : "cc", "memory");

    return res;
}


/*
 * "xaddq  r, [m]":
 *
 *     temp = [m];
 *     [m] += r;
 *     r = temp;
 *
 *
 * The "+r" is any register, %rax (%r0) - %r16.
 * The "cc" means that flags were changed.
 */

static ngx_inline ngx_atomic_int_t
ngx_atomic_fetch_add(ngx_atomic_t *value, ngx_atomic_int_t add)
{
    __asm__ volatile (

         NGX_SMP_LOCK
    "    xaddq  %0, %1;   "

    : "+q" (add) : "m" (*value) : "cc", "memory");

    return add;
}


#define ngx_memory_barrier()       __asm__ volatile ("" ::: "memory")