root/trunk/mmap.c @ 79

#undef ALLOC_DEBUG

#include <stdio.h>
#include <assert.h>
#include <limits.h>
#include <string.h>
#include <stdlib.h>

/* mmap */
#ifdef ZEND_WIN32
#   define ftruncate chsize
#   define getuid() 0
#   define XCacheCreateFileMapping(size, perm, name) \
        CreateFileMapping(INVALID_HANDLE_VALUE, NULL, perm, (sizeof(xc_shmsize_t) > 4) ? size >> 32 : 0, size & 0xffffffff, name)
#   define XCACHE_MAP_FAILED NULL
#   define munmap(p, s) UnmapViewOfFile(p)
#else
#   include <unistd.h>
/* make sure to mark(change) it to NULL to keep consistent */
#   define XCACHE_MAP_FAILED MAP_FAILED
#endif

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#ifndef ZEND_WIN32
#include <sys/mman.h>
#endif

#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;
    char *name;
    int newfile;
#ifdef ZEND_WIN32
    HANDLE hmap;
    HANDLE hmap_ro;
#endif
};

#undef NDEBUG
#ifdef ALLOC_DEBUG
#   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)
#define PTR_ADD(ptr, v) (((char *) (ptr)) + (v))
#define PTR_SUB(ptr, v) (((char *) (ptr)) - (v))

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 = PTR_SUB(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 = PTR_ADD(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;
        */
    }
#ifdef ZEND_WIN32
    if (shm->hmap) {
        CloseHandle(shm->hmap);
    }
    if (shm->hmap_ro) {
        CloseHandle(shm->hmap_ro);
    }
#endif

    if (shm->name) {
#ifdef __CYGWIN__
        if (shm->newfile) {
            unlink(shm->name);
        }
#endif
        free(shm->name);
    }
    /*
    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) /* {{{ */
{
#ifdef ZEND_WIN32
#   define TMP_PATH "XCache"
#else
#   define TMP_PATH "/tmp/XCache"
#endif
    xc_shm_t *shm = NULL;
    int fd = -1;
    int ro_ok;
    volatile void *romem;
    char tmpname[sizeof(TMP_PATH) - 1 + 100];

    CHECK(shm = calloc(1, sizeof(xc_shm_t)), "shm OOM");
    shm->size = size;

    if (path == NULL || !path[0]) {
        static int inc = 0;
        snprintf(tmpname, sizeof(tmpname) - 1, "%s.%d.%d.%d", TMP_PATH, (int) getuid(), inc ++, rand());
        path = tmpname;
    }

    shm->name = strdup(path);

#ifndef ZEND_WIN32
#   define XCACHE_MMAP_PERMISSION (S_IRUSR | S_IWUSR)
    fd = open(shm->name, O_RDWR, XCACHE_MMAP_PERMISSION);
    if (fd == -1) {
        /* do not create file in /dev */
        if (strncmp(shm->name, "/dev", 4) == 0) {
            goto err;
        }
        fd = open(shm->name, O_CREAT | O_RDWR, XCACHE_MMAP_PERMISSION);
        shm->newfile = 1;
        if (fd == -1) {
            goto err;
        }
    }
    ftruncate(fd, size);
#endif

#ifdef ZEND_WIN32
    shm->hmap = XCacheCreateFileMapping(size, PAGE_READWRITE, shm->name);
    shm->ptr = (LPSTR) MapViewOfFile(shm->hmap, FILE_MAP_WRITE, 0, 0, 0);
#else
    shm->ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
#endif

    if (shm->ptr == XCACHE_MAP_FAILED) {
        shm->ptr = NULL;
        goto err;
    }

    /* {{{ readonly protection, mmap it readonly and check if ptr_ro works */
    if (readonly_protection) {
        ro_ok = 0;

#ifdef ZEND_WIN32
        shm->hmap_ro = XCacheCreateFileMapping(size, PAGE_READONLY, shm->name);
        shm->ptr_ro = (LPSTR) MapViewOfFile(shm->hmap_ro, FILE_MAP_READ, 0, 0, 0);
#else
        shm->ptr_ro = mmap(NULL, size, PROT_READ, MAP_SHARED, fd, 0);
#endif
        if (shm->ptr_ro == XCACHE_MAP_FAILED) {
            shm->ptr_ro = NULL;
        }
        romem = shm->ptr_ro;

        do {
            if (romem == NULL || romem == 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 = PTR_SUB(shm->ptr_ro, (char *) shm->ptr);
            /* no overlap */
            assert(abs(shm->diff) >= size);
        }
        else {
            if (shm->ptr_ro) {
                munmap(shm->ptr_ro, size);
            }
#ifdef ZEND_WIN32
            if (shm->hmap_ro) {
                CloseHandle(shm->hmap_ro);
            }
#endif
            shm->ptr_ro = NULL;
            shm->diff = 0;
        }
    }

    /* }}} */

    close(fd);
#ifndef __CYGWIN__
    if (shm->newfile) {
        unlink(shm->name);
    }
#endif

    return shm;

err:
    if (fd != -1) {
        close(fd);
    }
    if (shm) {
        xc_shm_destroy(shm);
    }
    return NULL;
}
/* }}} */

void *xc_shm_ptr(xc_shm_t *shm) /* {{{ */
{
    return shm->ptr;
}
/* }}} */