shared_alloc_posix.c

/*
 +----------------------------------------------------------------------+
 | Zend OPcache |
 +----------------------------------------------------------------------+
 | Copyright (c) The PHP Group |
 +----------------------------------------------------------------------+
 | This source file is subject to version 3.01 of the PHP license, |
 | that is bundled with this package in the file LICENSE, and is |
 | available through the world-wide-web at the following url: |
 | https://www.php.net/license/3_01.txt |
 | If you did not receive a copy of the PHP license and are unable to |
 | obtain it through the world-wide-web, please send a note to |
 | license@php.net so we can mail you a copy immediately. |
 +----------------------------------------------------------------------+
 | Authors: Andi Gutmans <andi@php.net> |
 | Zeev Suraski <zeev@php.net> |
 | Stanislav Malyshev <stas@zend.com> |
 | Dmitry Stogov <dmitry@php.net> |
 +----------------------------------------------------------------------+
*/

#include"zend_shared_alloc.h"

#ifdefUSE_SHM_OPEN

#include<sys/types.h>
#include<sys/stat.h>
#include<stdio.h>
#include<fcntl.h>
#include<sys/mman.h>
#include<unistd.h>
#include<stdlib.h>

typedefstruct {
zend_shared_segmentcommon;
intshm_fd;
} zend_shared_segment_posix;

staticintcreate_segments(size_trequested_size, zend_shared_segment_posix***shared_segments_p, int*shared_segments_count, constchar**error_in)
{
zend_shared_segment_posix*shared_segment;
charshared_segment_name[sizeof("/ZendAccelerator.") +20];
intshared_segment_flags=O_RDWR|O_CREAT|O_TRUNC;
mode_tshared_segment_mode=0600;

#if defined(HAVE_SHM_CREATE_LARGEPAGE)
/**
 * architectures have 3 entries max and we are interested
 * from the second offset minimum to be worthy creating
 * a special shared segment tagged as 'large'.
 * only then amd64/i386/arm64 and perharps risc64*
 * archs are on interest here.
 */
size_ti, shared_segment_sizes=0, shared_segment_lg_index=0;
size_tshared_segment_sindexes[3] = {0};
constsize_tentries=sizeof(shared_segment_sindexes) / sizeof(shared_segment_sindexes[0]);

shared_segment_sizes=getpagesizes(shared_segment_sindexes, entries);

if (shared_segment_sizes>0) {
for (i=shared_segment_sizes-1; i >= 0; i--) {
if (shared_segment_sindexes[i] !=0&&
 !(requested_size % shared_segment_sindexes[i])) {
shared_segment_lg_index=i;
break;
 }
 }
 }
#endif

*shared_segments_count=1;
*shared_segments_p= (zend_shared_segment_posix**) calloc(1, sizeof(zend_shared_segment_posix) +sizeof(void*));
if (!*shared_segments_p) {
*error_in="calloc";
returnALLOC_FAILURE;
 }
shared_segment= (zend_shared_segment_posix*)((char*)(*shared_segments_p) +sizeof(void*));
 (*shared_segments_p)[0] =shared_segment;

snprintf(shared_segment_name, sizeof(shared_segment_name), "/ZendAccelerator.%d", getpid());
#if defined(HAVE_SHM_CREATE_LARGEPAGE)
if (shared_segment_lg_index>0) {
shared_segment->shm_fd=shm_create_largepage(shared_segment_name, shared_segment_flags, shared_segment_lg_index, SHM_LARGEPAGE_ALLOC_DEFAULT, shared_segment_mode);
if (shared_segment->shm_fd!=-1) {
 goto truncate_segment;
 }
 }
#endif

shared_segment->shm_fd=shm_open(shared_segment_name, shared_segment_flags, shared_segment_mode);
if (shared_segment->shm_fd==-1) {
*error_in="shm_open";
returnALLOC_FAILURE;
 }

#if defined(HAVE_SHM_CREATE_LARGEPAGE)
truncate_segment:
#endif
if (ftruncate(shared_segment->shm_fd, requested_size) !=0) {
*error_in="ftruncate";
shm_unlink(shared_segment_name);
returnALLOC_FAILURE;
 }

shared_segment->common.p=mmap(0, requested_size, PROT_READ | PROT_WRITE, MAP_SHARED, shared_segment->shm_fd, 0);
if (shared_segment->common.p==MAP_FAILED) {
*error_in="mmap";
shm_unlink(shared_segment_name);
returnALLOC_FAILURE;
 }
shm_unlink(shared_segment_name);

shared_segment->common.pos=0;
shared_segment->common.size=requested_size;

returnALLOC_SUCCESS;
}

staticintdetach_segment(zend_shared_segment_posix*shared_segment)
{
munmap(shared_segment->common.p, shared_segment->common.size);
close(shared_segment->shm_fd);
return0;
}

staticsize_tsegment_type_size(void)
{
returnsizeof(zend_shared_segment_posix);
}

constzend_shared_memory_handlerszend_alloc_posix_handlers= {
 (create_segments_t)create_segments,
 (detach_segment_t)detach_segment,
segment_type_size
};

#endif/* USE_SHM_OPEN */