source: trunk/xcache/xc_lock.c @ 1206

#include "xc_lock.h"
#include "xcache.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#ifdef ZEND_WIN32
#   include <process.h>
#else
#   include <unistd.h>
#   include <fcntl.h>
#   include <errno.h>
#endif

/* {{{ detect what type of lock is needed */
#ifdef ZTS
#   define XC_LOCK_NEED_TS
#endif

#ifndef ZEND_WIN32
#   define XC_LOCK_NEED_INTERPROCESS
#endif

#if defined(XC_LOCK_NEED_TS) && defined(XC_LOCK_NEED_INTERPROCESS)
/* allow switching off interprocess support */
#   define XC_LOCK_HAVE_INTERPROCESS_SWITCH
#endif
/* }}} */

/* {{{ detect which lock is needed */
#if defined(XC_LOCK_NEED_TS) && defined(XC_LOCK_NEED_INTERPROCESS)
#   ifdef PTHREAD
#       define XC_LOCK_USE_PTHREAD
#       ifndef _POSIX_THREAD_PROCESS_SHARED
#           define XC_LOCK_USE_FCNTL
#       endif
#   else
#       define XC_LOCK_USE_TSRM
#       define XC_LOCK_USE_FCNTL
#   endif
#elif defined(XC_LOCK_NEED_TS)
#   define XC_LOCK_USE_TSRM
#elif defined(XC_LOCK_NEED_INTERPROCESS)
#   define XC_LOCK_USE_FCNTL
#else
#   define XC_LOCK_USE_NOOP
#endif
/* }}} */

/* {{{ fcntl lock impl */
#ifdef XC_LOCK_USE_FCNTL
#ifndef ZEND_WIN32
typedef int HANDLE;
#   ifndef INVALID_HANDLE_VALUE
#       define INVALID_HANDLE_VALUE -1
#   endif
#else
#   define close(h) CloseHandle(h)
#   define open(filename, mode, permission) CreateFile(filename, \
        GENERIC_READ | GENERIC_WRITE, \
        FILE_SHARE_READ | FILE_SHARE_WRITE, \
        NULL, \
        OPEN_ALWAYS, \
        FILE_ATTRIBUTE_NORMAL, \
        NULL)
#endif

typedef struct {
    HANDLE fd;
    char *pathname;
} xc_fcntl_lock_t;

#ifndef ZEND_WIN32
#   define LCK_WR F_WRLCK
#   define LCK_RD F_RDLCK
#   define LCK_UN F_UNLCK
#   define LCK_NB 0
static inline int dolock(xc_fcntl_lock_t *lck, int type)
{
    int ret;
    struct flock lock;

    lock.l_type = type;
    lock.l_start = 0;
    lock.l_whence = SEEK_SET;
    lock.l_len = 1;
    lock.l_pid = 0;

    do {
        ret = fcntl(lck->fd, F_SETLKW, &lock);
    } while (ret < 0 && errno == EINTR);
    return ret;
}
#else

#   include <win32/flock.h>
#   include <io.h>
#   include <fcntl.h>
#   include <sys/types.h>
#   include <sys/stat.h>
#   undef errno
#   define errno GetLastError()
#   define getuid() 0
#   define LCK_WR LOCKFILE_EXCLUSIVE_LOCK
#   define LCK_RD 0
#   define LCK_UN 0
#   define LCK_NB LOCKFILE_FAIL_IMMEDIATELY
static inline int dolock(xc_fcntl_lock_t *lck, int type)
{
    static OVERLAPPED offset = {0, 0, 0, 0, NULL};

    if (type == LCK_UN) {
        return UnlockFileEx(lck->fd, 0, 1, 0, &offset);
    }
    else {
        return LockFileEx(lck->fd, type, 0, 1, 0, &offset);
    }
}
#endif
/* }}} */

static zend_bool xc_fcntl_init(xc_fcntl_lock_t *lck, const char *pathname) /* {{{ */
{
    HANDLE fd;
    int size;
    char *myname;

    if (pathname == NULL) {
        static int instanceId = 0;
        const char default_tmpdir[] = { DEFAULT_SLASH, 't', 'm', 'p', '\0' };
        const char *tmpdir;

        tmpdir = getenv("TEMP");
        if (!tmpdir) {
            tmpdir = getenv("TMP");
            if (!tmpdir) {
                tmpdir = default_tmpdir;
            }
        }
        size = strlen(tmpdir) + sizeof("/.xcache.lock") - 1 + 3 * 10 + 100;
        myname = malloc(size);
        snprintf(myname, size - 1, "%s%c.xcache.%d.%d.%d.lock", tmpdir, DEFAULT_SLASH, (int) getuid(), (int) getpid(), ++instanceId);
        pathname = myname;
    }
    else {
        myname = NULL;
    }

    fd = open(pathname, O_RDWR|O_CREAT, 0666);

    if (fd != INVALID_HANDLE_VALUE) {

#ifndef __CYGWIN__
        unlink(pathname);
#endif
        lck->fd = fd;
        size = strlen(pathname) + 1;
        lck->pathname = malloc(size);
        memcpy(lck->pathname, pathname, size);
    }
    else {
        zend_error(E_ERROR, "xc_fcntl_create: open(%s, O_RDWR|O_CREAT, 0666) failed:", pathname);
        lck = NULL;
    }

    if (myname) {
        free(myname);
    }

    return lck ? 1 : 0;
}
/* }}} */
static void xc_fcntl_destroy(xc_fcntl_lock_t *lck) /* {{{ */
{
    close(lck->fd);
#ifdef __CYGWIN__
    unlink(lck->pathname);
#endif
    free(lck->pathname);
}
/* }}} */
static void xc_fcntl_lock(xc_fcntl_lock_t *lck) /* {{{ */
{
    if (dolock(lck, LCK_WR) < 0) {
        zend_error(E_ERROR, "xc_fcntl_lock failed errno:%d", errno);
    }
}
/* }}} */
static void xc_fcntl_rdlock(xc_fcntl_lock_t *lck) /* {{{ */
{
    if (dolock(lck, LCK_RD) < 0) {
        zend_error(E_ERROR, "xc_fcntl_lock failed errno:%d", errno);
    }
}
/* }}} */
static void xc_fcntl_unlock(xc_fcntl_lock_t *lck) /* {{{ */
{
    if (dolock(lck, LCK_UN) < 0) {
        zend_error(E_ERROR, "xc_fcntl_unlock failed errno:%d", errno);
    }
}
/* }}} */
#endif /* XC_LOCK_USE_FCNTL */

struct _xc_lock_t {
#ifdef XC_LOCK_USE_NOOP
    int dummy;
#endif

#ifdef XC_LOCK_USE_TSRM
    MUTEX_T tsrm_mutex;
#endif

#ifdef XC_LOCK_HAVE_INTERPROCESS_SWITCH
    zend_bool interprocess;
#endif

#ifdef XC_LOCK_USE_PTHREAD
    pthread_mutex_t pthread_mutex;
#endif

#ifdef XC_LOCK_USE_FCNTL
    xc_fcntl_lock_t fcntl_lock;
#endif

#ifndef NDEBUG
    zend_bool locked;
#endif
};

#ifdef XC_LOCK_HAVE_INTERPROCESS_SWITCH
#   define XC_LOCK_INTERPROCESS (lck->interprocess)
#else
#   define XC_LOCK_INTERPROCESS 1
#endif

size_t xc_lock_size(void) /* {{{ */
{
    return sizeof(xc_lock_t);
}
/* }}} */
xc_lock_t *xc_lock_init(xc_lock_t *lck, const char *pathname, unsigned char interprocess) /* {{{ */
{
#ifdef XC_LOCK_HAVE_INTERPROCESS_SWITCH
    lck->interprocess = interprocess;
#endif

#ifdef XC_LOCK_USE_PTHREAD
    {
        pthread_mutexattr_t psharedm;
        pthread_mutexattr_init(&psharedm);
        pthread_mutexattr_setpshared(&psharedm, XC_LOCK_INTERPROCESS ? PTHREAD_PROCESS_PRIVATE : PTHREAD_PROCESS_SHARED);
        pthread_mutex_init(&lck->pthread_mutex, &psharedm);
    }
#endif

#ifdef XC_LOCK_USE_TSRM
    lck->tsrm_mutex = tsrm_mutex_alloc();
#endif

#ifdef XC_LOCK_USE_FCNTL
    if (XC_LOCK_INTERPROCESS) {
        xc_fcntl_init(&lck->fcntl_lock, pathname);
    }
#endif

#ifndef NDEBUG
    lck->locked = 0;
#endif

    return lck;
}
/* }}} */
void xc_lock_destroy(xc_lock_t *lck) /* {{{ */
{
#ifdef XC_LOCK_USE_PTHREAD
    pthread_mutex_destroy(&lck->pthread_mutex);
#endif

#ifdef XC_LOCK_USE_TSRM
    tsrm_mutex_free(lck->tsrm_mutex);
    lck->tsrm_mutex = NULL;
#endif

#ifdef XC_LOCK_USE_FCNTL
    if (XC_LOCK_INTERPROCESS) {
        xc_fcntl_destroy(&lck->fcntl_lock);
    }
#endif
}
/* }}} */
void xc_lock(xc_lock_t *lck) /* {{{ */
{
#ifdef XC_LOCK_USE_PTHREAD
    if (pthread_mutex_lock(&lck->pthread_mutex) < 0) {
        zend_error(E_ERROR, "xc_lock failed errno:%d", errno);
    }
#endif

#ifdef XC_LOCK_USE_TSRM
    if (tsrm_mutex_lock(lck->tsrm_mutex) < 0) {
        zend_error(E_ERROR, "xc_lock failed errno:%d", errno);
    }
#endif

#ifdef XC_LOCK_USE_FCNTL
    if (XC_LOCK_INTERPROCESS) {
        xc_fcntl_lock(&lck->fcntl_lock);
    }
#endif

#ifndef NDEBUG
    assert(!lck->locked);
    lck->locked = 1;
    assert(lck->locked);
#endif
}
/* }}} */
void xc_rdlock(xc_lock_t *lck) /* {{{ */
{
#ifdef XC_LOCK_USE_PTHREAD
    if (pthread_mutex_lock(&lck->pthread_mutex) < 0) {
        zend_error(E_ERROR, "xc_rdlock failed errno:%d", errno);
    }
#endif

#ifdef XC_LOCK_USE_TSRM
    if (tsrm_mutex_lock(lck->tsrm_mutex) < 0) {
        zend_error(E_ERROR, "xc_rdlock failed errno:%d", errno);
    }
#endif

#ifdef XC_LOCK_USE_FCNTL
    if (XC_LOCK_INTERPROCESS) {
        xc_fcntl_lock(&lck->fcntl_lock);
    }
#endif

#ifndef NDEBUG
    assert(!lck->locked);
    lck->locked = 1;
    assert(lck->locked);
#endif
}
/* }}} */
void xc_unlock(xc_lock_t *lck) /* {{{ */
{
#ifndef NDEBUG
    assert(lck->locked);
    lck->locked = 0;
    assert(!lck->locked);
#endif

#ifdef XC_LOCK_USE_FCNTL
    if (XC_LOCK_INTERPROCESS) {
        xc_fcntl_unlock(&lck->fcntl_lock);
    }
#endif

#ifdef XC_LOCK_USE_TSRM
    if (tsrm_mutex_unlock(lck->tsrm_mutex) < 0) {
        zend_error(E_ERROR, "xc_unlock failed errno:%d", errno);
    }
#endif

#ifdef XC_LOCK_USE_PTHREAD
    if (pthread_mutex_unlock(&lck->pthread_mutex) < 0) {
        zend_error(E_ERROR, "xc_unlock failed errno:%d", errno);
    }
#endif
}
/* }}} */