/* * Mesa 3-D graphics library * * Copyright (C) 1999-2005 Brian Paul All Rights Reserved. * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included * in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR * OTHER DEALINGS IN THE SOFTWARE. */ /** * \file glapi_execmem.c * * Function for allocating executable memory for dispatch stubs. * * Copied from main/execmem.c and simplified for dispatch stubs. */ #include "c99_compat.h" #include "c11/threads.h" #include "u_execmem.h" #define EXEC_MAP_SIZE (4*1024) static mtx_t exec_mutex = _MTX_INITIALIZER_NP; static unsigned int head = 0; static unsigned char *exec_mem = (unsigned char *)0; #if defined(__linux__) || defined(__OpenBSD__) || defined(_NetBSD__) || defined(__sun) || defined(__HAIKU__) #include <unistd.h> #include <sys/mman.h> #ifdef MESA_SELINUX #include <selinux/selinux.h> #endif #ifndef MAP_ANONYMOUS #define MAP_ANONYMOUS MAP_ANON #endif /* * Dispatch stubs are of fixed size and never freed. Thus, we do not need to * overlay a heap, we just mmap a page and manage through an index. */ static int init_map(void) { #ifdef MESA_SELINUX if (is_selinux_enabled()) { if (!security_get_boolean_active("allow_execmem") || !security_get_boolean_pending("allow_execmem")) return 0; } #endif if (!exec_mem) exec_mem = mmap(NULL, EXEC_MAP_SIZE, PROT_EXEC | PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); return (exec_mem != MAP_FAILED); } #elif defined(_WIN32) #include <windows.h> /* * Avoid Data Execution Prevention. */ static int init_map(void) { exec_mem = VirtualAlloc(NULL, EXEC_MAP_SIZE, MEM_COMMIT, PAGE_EXECUTE_READWRITE); return (exec_mem != NULL); } #else #include <stdlib.h> static int init_map(void) { exec_mem = malloc(EXEC_MAP_SIZE); return (exec_mem != NULL); } #endif void * u_execmem_alloc(unsigned int size) { void *addr = NULL; mtx_lock(&exec_mutex); if (!init_map()) goto bail; /* free space check, assumes no integer overflow */ if (head + size > EXEC_MAP_SIZE) goto bail; /* allocation, assumes proper addr and size alignement */ addr = exec_mem + head; head += size; bail: mtx_unlock(&exec_mutex); return addr; }