From 2ec8cfcd7d34415a99c3f3db3024ae954c00d0dd Mon Sep 17 00:00:00 2001 From: Maxim Dounin Date: Mon, 27 Apr 2015 18:25:42 +0300 Subject: 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 --- src/core/ngx_cycle.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'src/core/ngx_cycle.c') diff --git a/src/core/ngx_cycle.c b/src/core/ngx_cycle.c index d24245fb8..4852e3bbe 100644 --- a/src/core/ngx_cycle.c +++ b/src/core/ngx_cycle.c @@ -863,6 +863,22 @@ ngx_init_zone_pool(ngx_cycle_t *cycle, ngx_shm_zone_t *zn) return NGX_OK; } +#if (NGX_WIN32) + + /* remap at the required address */ + + if (ngx_shm_remap(&zn->shm, sp->addr) != NGX_OK) { + return NGX_ERROR; + } + + sp = (ngx_slab_pool_t *) zn->shm.addr; + + if (sp == sp->addr) { + return NGX_OK; + } + +#endif + ngx_log_error(NGX_LOG_EMERG, cycle->log, 0, "shared zone \"%V\" has no equal addresses: %p vs %p", &zn->shm.name, sp->addr, sp); -- cgit v1.2.3