Core: fix misallocation at ngx_crypt_apr1 (ticket #412). Found by using auth_basic.t from mdounin nginx-tests under valgrind. ==10470== Invalid write of size 1 ==10470== at 0x43603D: ngx_crypt_to64 (ngx_crypt.c:168) ==10470== by 0x43648E: ngx_crypt (ngx_crypt.c:153) ==10470== by 0x489D8B: ngx_http_auth_basic_crypt_handler (ngx_http_auth_basic_module.c:297) ==10470== by 0x48A24A: ngx_http_auth_basic_handler (ngx_http_auth_basic_module.c:240) ==10470== by 0x44EAB9: ngx_http_core_access_phase (ngx_http_core_module.c:1121) ==10470== by 0x44A822: ngx_http_core_run_phases (ngx_http_core_module.c:895) ==10470== by 0x44A932: ngx_http_handler (ngx_http_core_module.c:878) ==10470== by 0x455EEF: ngx_http_process_request (ngx_http_request.c:1852) ==10470== by 0x456527: ngx_http_process_request_headers (ngx_http_request.c:1283) ==10470== by 0x456A91: ngx_http_process_request_line (ngx_http_request.c:964) ==10470== by 0x457097: ngx_http_wait_request_handler (ngx_http_request.c:486) ==10470== by 0x4411EE: ngx_epoll_process_events (ngx_epoll_module.c:691) ==10470== Address 0x5866fab is 0 bytes after a block of size 27 alloc'd ==10470== at 0x4A074CD: malloc (vg_replace_malloc.c:236) ==10470== by 0x43B251: ngx_alloc (ngx_alloc.c:22) ==10470== by 0x421B0D: ngx_malloc (ngx_palloc.c:119) ==10470== by 0x421B65: ngx_pnalloc (ngx_palloc.c:147) ==10470== by 0x436368: ngx_crypt (ngx_crypt.c:140) ==10470== by 0x489D8B: ngx_http_auth_basic_crypt_handler (ngx_http_auth_basic_module.c:297) ==10470== by 0x48A24A: ngx_http_auth_basic_handler (ngx_http_auth_basic_module.c:240) ==10470== by 0x44EAB9: ngx_http_core_access_phase (ngx_http_core_module.c:1121) ==10470== by 0x44A822: ngx_http_core_run_phases (ngx_http_core_module.c:895) ==10470== by 0x44A932: ngx_http_handler (ngx_http_core_module.c:878) ==10470== by 0x455EEF: ngx_http_process_request (ngx_http_request.c:1852) ==10470== by 0x456527: ngx_http_process_request_headers (ngx_http_request.c:1283) ==10470==

/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>


/*
 * find the middle queue element if the queue has odd number of elements
 * or the first element of the queue's second part otherwise
 */

ngx_queue_t *
ngx_queue_middle(ngx_queue_t *queue)
{
    ngx_queue_t  *middle, *next;

    middle = ngx_queue_head(queue);

    if (middle == ngx_queue_last(queue)) {
        return middle;
    }

    next = ngx_queue_head(queue);

    for ( ;; ) {
        middle = ngx_queue_next(middle);

        next = ngx_queue_next(next);

        if (next == ngx_queue_last(queue)) {
            return middle;
        }

        next = ngx_queue_next(next);

        if (next == ngx_queue_last(queue)) {
            return middle;
        }
    }
}


/* the stable insertion sort */

void
ngx_queue_sort(ngx_queue_t *queue,
    ngx_int_t (*cmp)(const ngx_queue_t *, const ngx_queue_t *))
{
    ngx_queue_t  *q, *prev, *next;

    q = ngx_queue_head(queue);

    if (q == ngx_queue_last(queue)) {
        return;
    }

    for (q = ngx_queue_next(q); q != ngx_queue_sentinel(queue); q = next) {

        prev = ngx_queue_prev(q);
        next = ngx_queue_next(q);

        ngx_queue_remove(q);

        do {
            if (cmp(prev, q) <= 0) {
                break;
            }

            prev = ngx_queue_prev(prev);

        } while (prev != ngx_queue_sentinel(queue));

        ngx_queue_insert_after(prev, q);
    }
}