Mercurial > hg > nginx-quic
view src/core/ngx_array.c @ 6133:af7eba90645d
Win32: shared memory base addresses and remapping.
Two mechanisms are implemented to make it possible to store pointers
in shared memory on Windows, in particular on Windows Vista and later
versions with ASLR:
- The ngx_shm_remap() function added to allow remapping of a shared memory
zone to the address originally used for it in the master process. While
important, it doesn't solve the problem by itself as in many cases it's
not possible to use the address because of conflicts with other
allocations.
- We now create mappings at the same address in all processes by starting
mappings at predefined addresses normally unused by newborn processes.
These two mechanisms combined allow to use shared memory on Windows
almost without problems, including reloads.
Based on the patch by Sergey Brester:
http://mailman.nginx.org/pipermail/nginx-devel/2015-April/006836.html
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 27 Apr 2015 18:25:42 +0300 |
parents | 4fef8ed52389 |
children |
line wrap: on
line source
/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> ngx_array_t * ngx_array_create(ngx_pool_t *p, ngx_uint_t n, size_t size) { ngx_array_t *a; a = ngx_palloc(p, sizeof(ngx_array_t)); if (a == NULL) { return NULL; } if (ngx_array_init(a, p, n, size) != NGX_OK) { return NULL; } return a; } void ngx_array_destroy(ngx_array_t *a) { ngx_pool_t *p; p = a->pool; if ((u_char *) a->elts + a->size * a->nalloc == p->d.last) { p->d.last -= a->size * a->nalloc; } if ((u_char *) a + sizeof(ngx_array_t) == p->d.last) { p->d.last = (u_char *) a; } } void * ngx_array_push(ngx_array_t *a) { void *elt, *new; size_t size; ngx_pool_t *p; if (a->nelts == a->nalloc) { /* the array is full */ size = a->size * a->nalloc; p = a->pool; if ((u_char *) a->elts + size == p->d.last && p->d.last + a->size <= p->d.end) { /* * the array allocation is the last in the pool * and there is space for new allocation */ p->d.last += a->size; a->nalloc++; } else { /* allocate a new array */ new = ngx_palloc(p, 2 * size); if (new == NULL) { return NULL; } ngx_memcpy(new, a->elts, size); a->elts = new; a->nalloc *= 2; } } elt = (u_char *) a->elts + a->size * a->nelts; a->nelts++; return elt; } void * ngx_array_push_n(ngx_array_t *a, ngx_uint_t n) { void *elt, *new; size_t size; ngx_uint_t nalloc; ngx_pool_t *p; size = n * a->size; if (a->nelts + n > a->nalloc) { /* the array is full */ p = a->pool; if ((u_char *) a->elts + a->size * a->nalloc == p->d.last && p->d.last + size <= p->d.end) { /* * the array allocation is the last in the pool * and there is space for new allocation */ p->d.last += size; a->nalloc += n; } else { /* allocate a new array */ nalloc = 2 * ((n >= a->nalloc) ? n : a->nalloc); new = ngx_palloc(p, nalloc * a->size); if (new == NULL) { return NULL; } ngx_memcpy(new, a->elts, a->nelts * a->size); a->elts = new; a->nalloc = nalloc; } } elt = (u_char *) a->elts + a->size * a->nelts; a->nelts += n; return elt; }