XCache is a fast, stable PHP opcode cacher that has been proven and is now running on production servers under high load. https://xcache.lighttpd.net/
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191 lines
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#undef ALLOC_DEBUG
#include <stdio.h>
#include <assert.h>
#include <limits.h>
#include <string.h>
#include <stdlib.h>
/* mmap */
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/mman.h>
#include "php.h"
#include "myshm.h"
#ifndef max
#define max(a, b) ((a) < (b) ? (b) : (a))
#endif
// {{{ xc_shm_t
struct _xc_shm_t {
void *ptr;
void *ptr_ro;
long diff;
xc_shmsize_t size;
};
#ifdef ALLOC_DEBUG
# undef NDEBUG
# define inline
#else
# define NDEBUG
#endif
#include <assert.h>
/* }}} */
#define CHECK(x, e) do { if ((x) == NULL) { zend_error(E_ERROR, "XCache: " e); goto err; } } while (0)
int xc_shm_can_readonly(xc_shm_t *shm) /* {{{ */
{
return shm->ptr_ro != NULL;
}
/* }}} */
int xc_shm_is_readwrite(xc_shm_t *shm, const void *p) /* {{{ */
{
return p >= shm->ptr && (char *)p < (char *)shm->ptr + shm->size;
}
/* }}} */
int xc_shm_is_readonly(xc_shm_t *shm, const void *p) /* {{{ */
{
return xc_shm_can_readonly(shm) && p >= shm->ptr_ro && (char *)p < (char *)shm->ptr_ro + shm->size;
}
/* }}} */
void *xc_shm_to_readwrite(xc_shm_t *shm, void *p) /* {{{ */
{
if (shm->diff) {
assert(xc_shm_is_readonly(p));
p = p - shm->diff;
}
assert(xc_shm_is_readwrite(p));
return p;
}
/* }}} */
void *xc_shm_to_readonly(xc_shm_t *shm, void *p) /* {{{ */
{
assert(xc_shm_is_readwrite(p));
if (shm->diff) {
p = p + shm->diff;
assert(xc_shm_is_readonly(p));
}
return p;
}
/* }}} */
void xc_shm_destroy(xc_shm_t *shm) /* {{{ */
{
if (shm->ptr_ro) {
munmap(shm->ptr_ro, shm->size);
/*
shm->ptr_ro = NULL;
*/
}
if (shm->ptr) {
/* shm->size depends on shm->ptr */
munmap(shm->ptr, shm->size);
/*
shm->ptr = NULL;
*/
}
/*
shm->size = NULL;
shm->diff = 0;
*/
free(shm);
return;
}
/* }}} */
xc_shm_t *xc_shm_init(const char *path, xc_shmsize_t size, zend_bool readonly_protection) /* {{{ */
{
xc_shm_t *shm = NULL;
int fd;
int ro_ok;
volatile void *romem;
int created = 0;
CHECK(shm = calloc(1, sizeof(xc_shm_t)), "shm OOM");
shm->size = size;
if (path == NULL || !path[0]) {
path = "/tmp/xcache";
}
fd = open(path, O_RDWR, S_IRUSR | S_IWUSR);
if (fd == -1) {
created = 1;
fd = open(path, O_CREAT | O_RDWR, S_IRUSR | S_IWUSR);
if (fd == -1) {
if (created) {
unlink(path);
}
goto err;
}
}
ftruncate(fd, size);
shm->ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (shm->ptr == MAP_FAILED) {
shm->ptr = NULL;
close(fd);
if (created) {
unlink(path);
}
goto err;
}
ro_ok = 0;
if (readonly_protection) {
shm->ptr_ro = mmap(NULL, size, PROT_READ, MAP_SHARED, fd, 0);
romem = shm->ptr_ro;
/* {{{ check if ptr_ro works */
do {
if (shm->ptr_ro == MAP_FAILED || shm->ptr_ro == shm->ptr) {
break;
}
*(char *)shm->ptr = 1;
if (*(char *)romem != 1) {
break;
}
*(char *)shm->ptr = 2;
if (*(char *)romem != 2) {
break;
}
ro_ok = 1;
} while (0);
}
if (ro_ok) {
shm->diff = shm->ptr_ro - shm->ptr;
assert(abs(shm->diff) >= size);
}
else {
if (shm->ptr_ro != MAP_FAILED) {
munmap(shm->ptr_ro, size);
}
shm->ptr_ro = NULL;
shm->diff = 0;
}
/* }}} */
close(fd);
if (created) {
unlink(path);
}
return shm;
err:
if (shm) {
xc_shm_destroy(shm);
}
return NULL;
}
/* }}} */
void *xc_shm_ptr(xc_shm_t *shm) /* {{{ */
{
return shm->ptr;
}
/* }}} */