shared_alloc_posix.c

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/*
   +----------------------------------------------------------------------+
   | 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"
 
#ifdef USE_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>
 
typedef struct  {
    zend_shared_segment common;
    int shm_fd;
} zend_shared_segment_posix;
 
static int create_segments(size_t requested_size, zend_shared_segment_posix ***shared_segments_p, int *shared_segments_count, const char **error_in)
{
    zend_shared_segment_posix *shared_segment;
    char shared_segment_name[sizeof("/ZendAccelerator.") + 20];
    int shared_segment_flags = O_RDWR|O_CREAT|O_TRUNC;
    mode_t shared_segment_mode = 0600;
 
#if defined(HAVE_SHM_CREATE_LARGEPAGE)
    size_t i, shared_segment_sizes = 0, shared_segment_lg_index = 0;
    size_t shared_segment_sindexes[3] = {0};
    const size_t entries = 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";
        return ALLOC_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";
        return ALLOC_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);
        return ALLOC_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);
        return ALLOC_FAILURE;
    }
    shm_unlink(shared_segment_name);
 
    shared_segment->common.pos = 0;
    shared_segment->common.size = requested_size;
 
    return ALLOC_SUCCESS;
}
 
static int detach_segment(zend_shared_segment_posix *shared_segment)
{
    munmap(shared_segment->common.p, shared_segment->common.size);
    close(shared_segment->shm_fd);
    return 0;
}
 
static size_t segment_type_size(void)
{
    return sizeof(zend_shared_segment_posix);
}
 
const zend_shared_memory_handlers zend_alloc_posix_handlers = {
    (create_segments_t)create_segments,
    (detach_segment_t)detach_segment,
    segment_type_size
};
 
#endif /* USE_SHM_OPEN */