mp_fopen.c

这是linux下运行的mysql软件包,可用于linux 下安装 php + mysql + apach 的网络配置

				ret = EINVAL;
				goto err;
			}
		}

		/*
		 * If the user specifies DB_MPOOL_LAST or DB_MPOOL_NEW on a
		 * page get, we have to increment the last page in the file.
		 * Figure it out and save it away.
		 *
		 * Note correction: page numbers are zero-based, not 1-based.
		 */
		last_pgno = (db_pgno_t)(mbytes * (MEGABYTE / pagesize));
		last_pgno += (db_pgno_t)(bytes / pagesize);
		if (last_pgno != 0)
			--last_pgno;
		mfp->orig_last_pgno = mfp->last_pgno = last_pgno;

		/* Copy the file path into shared memory. */
		if ((ret = __memp_alloc(dbmp, dbmp->reginfo,
		    NULL, strlen(path) + 1, &mfp->path_off, &p)) != 0)
			goto err;
		memcpy(p, path, strlen(path) + 1);

		/* Copy the file identification string into shared memory. */
		if ((ret = __memp_alloc(dbmp, dbmp->reginfo,
		    NULL, DB_FILE_ID_LEN, &mfp->fileid_off, &p)) != 0)
			goto err;
		memcpy(p, dbmfp->fileid, DB_FILE_ID_LEN);
	}

	/* Copy the page cookie into shared memory. */
	if (dbmfp->pgcookie == NULL || dbmfp->pgcookie->size == 0) {
		mfp->pgcookie_len = 0;
		mfp->pgcookie_off = 0;
	} else {
		if ((ret = __memp_alloc(dbmp, dbmp->reginfo,
		    NULL, dbmfp->pgcookie->size, &mfp->pgcookie_off, &p)) != 0)
			goto err;
		memcpy(p, dbmfp->pgcookie->data, dbmfp->pgcookie->size);
		mfp->pgcookie_len = dbmfp->pgcookie->size;
	}

	/*
	 * Prepend the MPOOLFILE to the list of MPOOLFILE's.
	 */
	R_LOCK(dbenv, dbmp->reginfo);
	ret = __db_mutex_setup(dbenv, dbmp->reginfo, &mfp->mutex,
	    MUTEX_NO_RLOCK);
	if (ret == 0)
		SH_TAILQ_INSERT_HEAD(&mp->mpfq, mfp, q, __mpoolfile);
	R_UNLOCK(dbenv, dbmp->reginfo);
	if (ret != 0)
		goto err;

check_map:
	/*
	 * If a file:
	 *	+ isn't temporary
	 *	+ is read-only
	 *	+ doesn't require any pgin/pgout support
	 *	+ the DB_NOMMAP flag wasn't set (in either the file open or
	 *	  the environment in which it was opened)
	 *	+ and is less than mp_mmapsize bytes in size
	 *
	 * we can mmap it instead of reading/writing buffers.  Don't do error
	 * checking based on the mmap call failure.  We want to do normal I/O
	 * on the file if the reason we failed was because the file was on an
	 * NFS mounted partition, and we can fail in buffer I/O just as easily
	 * as here.
	 *
	 * We'd like to test to see if the file is too big to mmap.  Since we
	 * don't know what size or type off_t's or size_t's are, or the largest
	 * unsigned integral type is, or what random insanity the local C
	 * compiler will perpetrate, doing the comparison in a portable way is
	 * flatly impossible.  Hope that mmap fails if the file is too large.
	 */
#define	DB_MAXMMAPSIZE	(10 * 1024 * 1024)	/* 10 MB. */
	if (F_ISSET(mfp, MP_CAN_MMAP)) {
		if (path == NULL)
			F_CLR(mfp, MP_CAN_MMAP);
		if (!F_ISSET(dbmfp, MP_READONLY))
			F_CLR(mfp, MP_CAN_MMAP);
		if (dbmfp->ftype != 0)
			F_CLR(mfp, MP_CAN_MMAP);
		if (LF_ISSET(DB_NOMMAP) || F_ISSET(dbenv, DB_ENV_NOMMAP))
			F_CLR(mfp, MP_CAN_MMAP);
		maxmap = dbenv->mp_mmapsize == 0 ?
		    DB_MAXMMAPSIZE : dbenv->mp_mmapsize;
		if (mbytes > maxmap / MEGABYTE ||
		    (mbytes == maxmap / MEGABYTE && bytes >= maxmap % MEGABYTE))
			F_CLR(mfp, MP_CAN_MMAP);

		dbmfp->addr = NULL;
		if (F_ISSET(mfp, MP_CAN_MMAP)) {
			dbmfp->len = (size_t)mbytes * MEGABYTE + bytes;
			if (__os_mapfile(dbenv, rpath,
			    dbmfp->fhp, dbmfp->len, 1, &dbmfp->addr) != 0) {
				dbmfp->addr = NULL;
				F_CLR(mfp, MP_CAN_MMAP);
			}
		}
	}

	dbmfp->mfp = mfp;

	F_SET(dbmfp, MP_OPEN_CALLED);

	/* Add the file to the process' list of DB_MPOOLFILEs. */
	MUTEX_THREAD_LOCK(dbenv, dbmp->mutexp);
	TAILQ_INSERT_TAIL(&dbmp->dbmfq, dbmfp, q);
	MUTEX_THREAD_UNLOCK(dbenv, dbmp->mutexp);

	if (0) {
err:		if (F_ISSET(dbmfp->fhp, DB_FH_VALID))
			(void)__os_closehandle(dbenv, dbmfp->fhp);

		if (mfp_alloc) {
			R_LOCK(dbenv, dbmp->reginfo);
			if (mfp->path_off != 0)
				__db_shalloc_free(dbmp->reginfo[0].addr,
				    R_ADDR(dbmp->reginfo, mfp->path_off));
			if (mfp->fileid_off != 0)
				__db_shalloc_free(dbmp->reginfo[0].addr,
				    R_ADDR(dbmp->reginfo, mfp->fileid_off));
			__db_shalloc_free(dbmp->reginfo[0].addr, mfp);
			R_UNLOCK(dbenv, dbmp->reginfo);
		}

	}
	if (rpath != NULL)
		__os_free(dbenv, rpath);
	return (ret);
}

/*
 * __memp_get_fileid --
 *	Return the file ID.
 *
 * XXX
 * Undocumented interface: DB private.
 */
static void
__memp_get_fileid(dbmfp, fidp)
	DB_MPOOLFILE *dbmfp;
	u_int8_t *fidp;
{
	/*
	 * No lock needed -- we're using the handle, it had better not
	 * be going away.
	 *
	 * !!!
	 * Get the fileID out of the region, not out of the DB_MPOOLFILE
	 * structure because the DB_MPOOLFILE reference is possibly short
	 * lived, and isn't to be trusted.
	 */
	memcpy(fidp, R_ADDR(
	    dbmfp->dbmp->reginfo, dbmfp->mfp->fileid_off), DB_FILE_ID_LEN);
}

/*
 * __memp_last_pgno --
 *	Return the page number of the last page in the file.
 *
 * XXX
 * Undocumented interface: DB private.
 */
static void
__memp_last_pgno(dbmfp, pgnoaddr)
	DB_MPOOLFILE *dbmfp;
	db_pgno_t *pgnoaddr;
{
	DB_ENV *dbenv;
	DB_MPOOL *dbmp;

	dbmp = dbmfp->dbmp;
	dbenv = dbmp->dbenv;

	R_LOCK(dbenv, dbmp->reginfo);
	*pgnoaddr = dbmfp->mfp->last_pgno;
	R_UNLOCK(dbenv, dbmp->reginfo);
}

/*
 * __memp_refcnt --
 *	Return the current reference count.
 *
 * XXX
 * Undocumented interface: DB private.
 */
static void
__memp_refcnt(dbmfp, cntp)
	DB_MPOOLFILE *dbmfp;
	db_pgno_t *cntp;
{
	DB_ENV *dbenv;

	dbenv = dbmfp->dbmp->dbenv;

	MUTEX_LOCK(dbenv, &dbmfp->mfp->mutex);
	*cntp = dbmfp->mfp->mpf_cnt;
	MUTEX_UNLOCK(dbenv, &dbmfp->mfp->mutex);
}

/*
 * __memp_set_unlink --
 *	Set unlink on last close flag.
 *
 * XXX
 * Undocumented interface: DB private.
 */
static void
__memp_set_unlink(dbmpf, set)
	DB_MPOOLFILE *dbmpf;
	int set;
{
	DB_ENV *dbenv;

	dbenv = dbmpf->dbmp->dbenv;

	MUTEX_LOCK(dbenv, &dbmpf->mfp->mutex);
	if (set)
		F_SET(dbmpf->mfp, MP_UNLINK);
	else
		F_CLR(dbmpf->mfp, MP_UNLINK);
	MUTEX_UNLOCK(dbenv, &dbmpf->mfp->mutex);
}

/*
 * memp_fclose --
 *	Close a backing file for the memory pool.
 */
static int
__memp_fclose(dbmfp, flags)
	DB_MPOOLFILE *dbmfp;
	u_int32_t flags;
{
	DB_ENV *dbenv;
	int ret, t_ret;

	dbenv = dbmfp->dbmp->dbenv;

	PANIC_CHECK(dbenv);

	/*
	 * XXX
	 * DB_MPOOL_DISCARD: Undocumented flag: DB private.
	 */
	ret = __db_fchk(dbenv, "DB_MPOOLFILE->close", flags, DB_MPOOL_DISCARD);

	if ((t_ret = __memp_fclose_int(dbmfp, flags)) != 0 && ret == 0)
		ret = t_ret;

	return (ret);
}

/*
 * __memp_fclose_int --
 *	Internal version of __memp_fclose.
 *
 * PUBLIC: int __memp_fclose_int __P((DB_MPOOLFILE *, u_int32_t));
 */
int
__memp_fclose_int(dbmfp, flags)
	DB_MPOOLFILE *dbmfp;
	u_int32_t flags;
{
	DB_ENV *dbenv;
	DB_MPOOL *dbmp;
	MPOOLFILE *mfp;
	char *rpath;
	int deleted, ret, t_ret;

	dbmp = dbmfp->dbmp;
	dbenv = dbmp->dbenv;
	ret = 0;

	/*
	 * We have to reference count DB_MPOOLFILE structures as other threads
	 * in the process may be using them.  Here's the problem:
	 *
	 * Thread A opens a database.
	 * Thread B uses thread A's DB_MPOOLFILE to write a buffer
	 *    in order to free up memory in the mpool cache.
	 * Thread A closes the database while thread B is using the
	 *    DB_MPOOLFILE structure.
	 *
	 * By opening all databases before creating any threads, and closing
	 * the databases after all the threads have exited, applications get
	 * better performance and avoid the problem path entirely.
	 *
	 * Regardless, holding the DB_MPOOLFILE to flush a dirty buffer is a
	 * short-term lock, even in worst case, since we better be the only
	 * thread of control using the DB_MPOOLFILE structure to read pages
	 * *into* the cache.  Wait until we're the only reference holder and
	 * remove the DB_MPOOLFILE structure from the list, so nobody else can
	 * find it.  We do this, rather than have the last reference holder
	 * (whoever that might be) discard the DB_MPOOLFILE structure, because
	 * we'd rather write error messages to the application in the close
	 * routine, not in the checkpoint/sync routine.
	 *
	 * !!!
	 * It's possible the DB_MPOOLFILE was never added to the DB_MPOOLFILE
	 * file list, check the DB_OPEN_CALLED flag to be sure.
	 */
	for (deleted = 0;;) {
		MUTEX_THREAD_LOCK(dbenv, dbmp->mutexp);
		if (dbmfp->ref == 1) {
			if (F_ISSET(dbmfp, MP_OPEN_CALLED))
				TAILQ_REMOVE(&dbmp->dbmfq, dbmfp, q);
			deleted = 1;
		}
		MUTEX_THREAD_UNLOCK(dbenv, dbmp->mutexp);

		if (deleted)
			break;
		__os_sleep(dbenv, 1, 0);
	}

	/* Complain if pinned blocks never returned. */
	if (dbmfp->pinref != 0) {
		__db_err(dbenv, "%s: close: %lu blocks left pinned",
		    __memp_fn(dbmfp), (u_long)dbmfp->pinref);
		ret = __db_panic(dbenv, DB_RUNRECOVERY);
	}

	/* Discard any mmap information. */
	if (dbmfp->addr != NULL &&
	    (ret = __os_unmapfile(dbenv, dbmfp->addr, dbmfp->len)) != 0)
		__db_err(dbenv, "%s: %s", __memp_fn(dbmfp), db_strerror(ret));

	/* Close the file; temporary files may not yet have been created. */
	if (F_ISSET(dbmfp->fhp, DB_FH_VALID) &&
	    (t_ret = __os_closehandle(dbenv, dbmfp->fhp)) != 0) {
		__db_err(dbenv, "%s: %s", __memp_fn(dbmfp), db_strerror(t_ret));
		if (ret == 0)
			ret = t_ret;
	}

	/* Discard the thread mutex. */
	if (dbmfp->mutexp != NULL)
		__db_mutex_free(dbenv, dbmp->reginfo, dbmfp->mutexp);

	/*
	 * Discard our reference on the the underlying MPOOLFILE, and close
	 * it if it's no longer useful to anyone.  It possible the open of
	 * the file never happened or wasn't successful, in which case, mpf
	 * will be NULL;
	 */
	if ((mfp = dbmfp->mfp) == NULL)
		goto done;

	/*
	 * If it's a temp file, all outstanding references belong to unflushed
	 * buffers.  (A temp file can only be referenced by one DB_MPOOLFILE).
	 * We don't care about preserving any of those buffers, so mark the
	 * MPOOLFILE as dead so that even the dirty ones just get discarded
	 * when we try to flush them.
	 */
	deleted = 0;
	MUTEX_LOCK(dbenv, &mfp->mutex);
	if (--mfp->mpf_cnt == 0 || LF_ISSET(DB_MPOOL_DISCARD)) {
		if (LF_ISSET(DB_MPOOL_DISCARD) ||
		    F_ISSET(mfp, MP_TEMP | MP_UNLINK))
			MPOOLFILE_IGNORE(mfp);
		if (F_ISSET(mfp, MP_UNLINK)) {
			if ((t_ret = __db_appname(dbmp->dbenv,
			    DB_APP_DATA, R_ADDR(dbmp->reginfo,
			    mfp->path_off), 0, NULL, &rpath)) != 0 && ret == 0)
				ret = t_ret;
			if (t_ret == 0) {
				if ((t_ret = __os_unlink(
				    dbmp->dbenv, rpath) != 0) && ret == 0)
					ret = t_ret;
				__os_free(dbenv, rpath);
			}
		}
		if (mfp->block_cnt == 0) {
			if ((t_ret =
			    __memp_mf_discard(dbmp, mfp)) != 0 && ret == 0)
				ret = t_ret;
			deleted = 1;
		}
	}
	if (deleted == 0)
		MUTEX_UNLOCK(dbenv, &mfp->mutex);

	/* Discard the DB_MPOOLFILE structure. */
done:	__os_free(dbenv, dbmfp->fhp);
	__os_free(dbenv, dbmfp);

	return (ret);
}

/*
 * __memp_mf_discard --
 *	Discard an MPOOLFILE.
 *
 * PUBLIC: int __memp_mf_discard __P((DB_MPOOL *, MPOOLFILE *));
 */
int
__memp_mf_discard(dbmp, mfp)
	DB_MPOOL *dbmp;
	MPOOLFILE *mfp;
{
	DB_ENV *dbenv;
	DB_FH fh;
	DB_MPOOL_STAT *sp;
	MPOOL *mp;
	char *rpath;
	int ret;

	dbenv = dbmp->dbenv;
	mp = dbmp->reginfo[0].primary;
	ret = 0;

	/*
	 * Expects caller to be holding the MPOOLFILE mutex.
	 *
	 * When discarding a file, we have to flush writes from it to disk.
	 * The scenario is that dirty buffers from this file need to be
	 * flushed to satisfy a future checkpoint, but when the checkpoint
	 * calls mpool sync, the sync code won't know anything about them.
	 */
	if (!F_ISSET(mfp, MP_DEADFILE) &&
	    (ret = __db_appname(dbenv, DB_APP_DATA,
	    R_ADDR(dbmp->reginfo, mfp->path_off), 0, NULL, &rpath)) == 0) {
		if ((ret = __os_open(dbenv, rpath, 0, 0, &fh)) == 0) {
			ret = __os_fsync(dbenv, &fh);
			(void)__os_closehandle(dbenv, &fh);
		}
		__os_free(dbenv, rpath);
	}

	/*
	 * We have to release the MPOOLFILE lock before acquiring the region
	 * lock so that we don't deadlock.  Make sure nobody ever looks at
	 * this structure again.
	 */
	MPOOLFILE_IGNORE(mfp);

	/* Discard the mutex we're holding. */
	MUTEX_UNLOCK(dbenv, &mfp->mutex);

	/* Delete from the list of MPOOLFILEs. */
	R_LOCK(dbenv, dbmp->reginfo);
	SH_TAILQ_REMOVE(&mp->mpfq, mfp, q, __mpoolfile);

	/* Copy the statistics into the region. */
	sp = &mp->stat;
	sp->st_cache_hit += mfp->stat.st_cache_hit;
	sp->st_cache_miss += mfp->stat.st_cache_miss;
	sp->st_map += mfp->stat.st_map;
	sp->st_page_create += mfp->stat.st_page_create;
	sp->st_page_in += mfp->stat.st_page_in;
	sp->st_page_out += mfp->stat.st_page_out;

	/* Clear the mutex this MPOOLFILE recorded. */
	__db_shlocks_clear(&mfp->mutex, dbmp->reginfo,
	    (REGMAINT *)R_ADDR(dbmp->reginfo, mp->maint_off));

	/* Free the space. */
	if (mfp->path_off != 0)
		__db_shalloc_free(dbmp->reginfo[0].addr,
		    R_ADDR(dbmp->reginfo, mfp->path_off));
	if (mfp->fileid_off != 0)
		__db_shalloc_free(dbmp->reginfo[0].addr,
		    R_ADDR(dbmp->reginfo, mfp->fileid_off));
	if (mfp->pgcookie_off != 0)
		__db_shalloc_free(dbmp->reginfo[0].addr,
		    R_ADDR(dbmp->reginfo, mfp->pgcookie_off));
	__db_shalloc_free(dbmp->reginfo[0].addr, mfp);

	R_UNLOCK(dbenv, dbmp->reginfo);

	return (ret);
}

/*
 * __memp_fn --
 *	On errors we print whatever is available as the file name.
 *
 * PUBLIC: char * __memp_fn __P((DB_MPOOLFILE *));
 */
char *
__memp_fn(dbmfp)
	DB_MPOOLFILE *dbmfp;
{
	return (__memp_fns(dbmfp->dbmp, dbmfp->mfp));
}

/*
 * __memp_fns --
 *	On errors we print whatever is available as the file name.
 *
 * PUBLIC: char * __memp_fns __P((DB_MPOOL *, MPOOLFILE *));
 *
 */
char *
__memp_fns(dbmp, mfp)
	DB_MPOOL *dbmp;
	MPOOLFILE *mfp;
{
	if (mfp->path_off == 0)
		return ((char *)"temporary");

	return ((char *)R_ADDR(dbmp->reginfo, mfp->path_off));
}