log.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

	}

	need_free = 0;
	hdrsize = HDR_NORMAL_SZ;
	is_hmac = 0;
	recsize = sizeof(LOGP);
	if (CRYPTO_ON(dbenv)) {
		hdrsize = HDR_CRYPTO_SZ;
		recsize = sizeof(LOGP);
		recsize += db_cipher->adj_size(recsize);
		is_hmac = 1;
	}
	if ((ret = __os_calloc(dbenv, 1, recsize + hdrsize, &tmp)) != 0)
		return (ret);
	need_free = 1;
	hdr = (HDR *)tmp;
	persist = (LOGP *)(tmp + hdrsize);
	/* Try to read the header. */
	if ((ret = __os_read(dbenv, &fh, tmp, recsize + hdrsize, &nw)) != 0 ||
	    nw != recsize + hdrsize) {
		if (ret == 0)
			status = DB_LV_INCOMPLETE;
		else
			/*
			 * The error was a fatal read error, not just an
			 * incompletely initialized log file.
			 */
			__db_err(dbenv, "Ignoring log file: %s: %s",
			    fname, db_strerror(ret));

		(void)__os_closehandle(dbenv, &fh);
		goto err;
	}
	(void)__os_closehandle(dbenv, &fh);

	/*
	 * Now we have to validate the persistent record.  We have
	 * several scenarios we have to deal with:
	 *
	 * 1.  User has crypto turned on:
	 *	- They're reading an old, unencrypted log file
	 *	  .  We will fail the record size match check below.
	 *	- They're reading a current, unencrypted log file
	 *	  .  We will fail the record size match check below.
	 *	- They're reading an old, encrypted log file [NOT YET]
	 *	  .  After decryption we'll fail the version check.  [NOT YET]
	 *	- They're reading a current, encrypted log file
	 *	  .  We should proceed as usual.
	 * 2.  User has crypto turned off:
	 *	- They're reading an old, unencrypted log file
	 *	  .  We will fail the version check.
	 *	- They're reading a current, unencrypted log file
	 *	  .  We should proceed as usual.
	 *	- They're reading an old, encrypted log file [NOT YET]
	 *	  .  We'll fail the magic number check (it is encrypted).
	 *	- They're reading a current, encrypted log file
	 *	  .  We'll fail the magic number check (it is encrypted).
	 */
	if (CRYPTO_ON(dbenv)) {
		/*
		 * If we are trying to decrypt an unencrypted log
		 * we can only detect that by having an unreasonable
		 * data length for our persistent data.
		 */
		if ((hdr->len - hdrsize) != sizeof(LOGP)) {
			__db_err(dbenv, "log record size mismatch");
			goto err;
		}
		/* Check the checksum and decrypt. */
		if ((ret = __db_check_chksum(dbenv, db_cipher, &hdr->chksum[0],
		    (u_int8_t *)persist, hdr->len - hdrsize, is_hmac)) != 0) {
			__db_err(dbenv, "log record checksum mismatch");
			goto err;
		}
		if ((ret = db_cipher->decrypt(dbenv, db_cipher->data,
		    &hdr->iv[0], (u_int8_t *)persist, hdr->len - hdrsize)) != 0)
			goto err;
	}

	/* Validate the header. */
	if (persist->magic != DB_LOGMAGIC) {
		__db_err(dbenv,
		    "Ignoring log file: %s: magic number %lx, not %lx",
		    fname, (u_long)persist->magic, (u_long)DB_LOGMAGIC);
		ret = EINVAL;
		goto err;
	}

	/*
	 * Set our status code to indicate whether the log file
	 * belongs to an unreadable or readable old version;  leave it
	 * alone if and only if the log file version is the current one.
	 */
	if (persist->version > DB_LOGVERSION) {
		/* This is a fatal error--the log file is newer than DB. */
		__db_err(dbenv,
		    "Ignoring log file: %s: unsupported log version %lu",
		    fname, (u_long)persist->version);
		ret = EINVAL;
		goto err;
	} else if (persist->version < DB_LOGOLDVER) {
		status = DB_LV_OLD_UNREADABLE;
		/*
		 * We don't want to set persistent info based on an
		 * unreadable region, so jump to "err".
		 */
		goto err;
	} else if (persist->version < DB_LOGVERSION)
		status = DB_LV_OLD_READABLE;

	/*
	 * Only if we have a current log do we verify the checksum.
	 * We could not check the checksum before checking the magic
	 * and version because old log hdrs have the length and checksum
	 * in a different location.
	 */
	if (!CRYPTO_ON(dbenv) && ((ret = __db_check_chksum(dbenv,
	    db_cipher, &hdr->chksum[0], (u_int8_t *)persist,
	    hdr->len - hdrsize, is_hmac)) != 0)) {
		__db_err(dbenv, "log record checksum mismatch");
		goto err;
	}

	/*
	 * If the log is readable so far and we're doing system initialization,
	 * set the region's persistent information based on the headers.
	 *
	 * Always set the current log file size.  Only set the next log file's
	 * size if the application hasn't set it already.
	 *
	 * XXX
	 * Always use the persistent header's mode, regardless of what was set
	 * in the current environment.  We've always done it this way, but it's
	 * probably a bug -- I can't think of a way not-changing the mode would
	 * be a problem, though.
	 */
	if (set_persist) {
		region = dblp->reginfo.primary;
		region->log_size = persist->log_size;
		if (region->log_nsize == 0)
			region->log_nsize = persist->log_size;
		region->persist.mode = persist->mode;
	}

err:	__os_free(dbenv, fname);
	if (need_free)
		__os_free(dbenv, tmp);
	*statusp = status;
	return (ret);
}

/*
 * __log_dbenv_refresh --
 *	Clean up after the log system on a close or failed open.  Called only
 * from __dbenv_refresh.  (Formerly called __log_close.)
 *
 * PUBLIC: int __log_dbenv_refresh __P((DB_ENV *));
 */
int
__log_dbenv_refresh(dbenv)
	DB_ENV *dbenv;
{
	DB_LOG *dblp;
	int ret, t_ret;

	dblp = dbenv->lg_handle;

	/* We may have opened files as part of XA; if so, close them. */
	F_SET(dblp, DBLOG_RECOVER);
	ret = __dbreg_close_files(dbenv);

	/* Discard the per-thread lock. */
	if (dblp->mutexp != NULL)
		__db_mutex_free(dbenv, &dblp->reginfo, dblp->mutexp);

	/* Detach from the region. */
	if ((t_ret =
	    __db_r_detach(dbenv, &dblp->reginfo, 0)) != 0 && ret == 0)
		ret = t_ret;

	/* Close open files, release allocated memory. */
	if (F_ISSET(&dblp->lfh, DB_FH_VALID) &&
	    (t_ret = __os_closehandle(dbenv, &dblp->lfh)) != 0 && ret == 0)
		ret = t_ret;
	if (dblp->dbentry != NULL)
		__os_free(dbenv, dblp->dbentry);

	__os_free(dbenv, dblp);

	dbenv->lg_handle = NULL;
	return (ret);
}

/*
 * __log_stat --
 *	Return log statistics.
 *
 * PUBLIC: int __log_stat __P((DB_ENV *, DB_LOG_STAT **, u_int32_t));
 */
int
__log_stat(dbenv, statp, flags)
	DB_ENV *dbenv;
	DB_LOG_STAT **statp;
	u_int32_t flags;
{
	DB_LOG *dblp;
	DB_LOG_STAT *stats;
	LOG *region;
	int ret;

	PANIC_CHECK(dbenv);
	ENV_REQUIRES_CONFIG(dbenv,
	    dbenv->lg_handle, "DB_ENV->log_stat", DB_INIT_LOG);

	*statp = NULL;
	if ((ret = __db_fchk(dbenv,
	    "DB_ENV->log_stat", flags, DB_STAT_CLEAR)) != 0)
		return (ret);

	dblp = dbenv->lg_handle;
	region = dblp->reginfo.primary;

	if ((ret = __os_umalloc(dbenv, sizeof(DB_LOG_STAT), &stats)) != 0)
		return (ret);

	/* Copy out the global statistics. */
	R_LOCK(dbenv, &dblp->reginfo);
	*stats = region->stat;
	if (LF_ISSET(DB_STAT_CLEAR))
		memset(&region->stat, 0, sizeof(region->stat));

	stats->st_magic = region->persist.magic;
	stats->st_version = region->persist.version;
	stats->st_mode = region->persist.mode;
	stats->st_lg_bsize = region->buffer_size;
	stats->st_lg_size = region->log_nsize;

	stats->st_region_wait = dblp->reginfo.rp->mutex.mutex_set_wait;
	stats->st_region_nowait = dblp->reginfo.rp->mutex.mutex_set_nowait;
	if (LF_ISSET(DB_STAT_CLEAR)) {
		dblp->reginfo.rp->mutex.mutex_set_wait = 0;
		dblp->reginfo.rp->mutex.mutex_set_nowait = 0;
	}
	stats->st_regsize = dblp->reginfo.rp->size;

	stats->st_cur_file = region->lsn.file;
	stats->st_cur_offset = region->lsn.offset;
	stats->st_disk_file = region->s_lsn.file;
	stats->st_disk_offset = region->s_lsn.offset;

	R_UNLOCK(dbenv, &dblp->reginfo);

	*statp = stats;
	return (0);
}

/*
 * __log_get_cached_ckp_lsn --
 *	Retrieve any last checkpoint LSN that we may have found on startup.
 *
 * PUBLIC: void __log_get_cached_ckp_lsn __P((DB_ENV *, DB_LSN *));
 */
void
__log_get_cached_ckp_lsn(dbenv, ckp_lsnp)
	DB_ENV *dbenv;
	DB_LSN *ckp_lsnp;
{
	DB_LOG *dblp;
	LOG *lp;

	dblp = (DB_LOG *)dbenv->lg_handle;
	lp = (LOG *)dblp->reginfo.primary;

	R_LOCK(dbenv, &dblp->reginfo);
	*ckp_lsnp = lp->cached_ckp_lsn;
	R_UNLOCK(dbenv, &dblp->reginfo);
}

/*
 * __log_region_size --
 *	Return the amount of space needed for the log region.
 *	Make the region large enough to hold txn_max transaction
 *	detail structures  plus some space to hold thread handles
 *	and the beginning of the shalloc region and anything we
 *	need for mutex system resource recording.
 */
static size_t
__log_region_size(dbenv)
	DB_ENV *dbenv;
{
	size_t s;

	s = dbenv->lg_regionmax + dbenv->lg_bsize;
#ifdef HAVE_MUTEX_SYSTEM_RESOURCES
	if (F_ISSET(dbenv, DB_ENV_THREAD))
		s += sizeof(REGMAINT) + LG_MAINT_SIZE;
#endif
	return (s);
}

/*
 * __log_region_destroy
 *	Destroy any region maintenance info.
 *
 * PUBLIC: void __log_region_destroy __P((DB_ENV *, REGINFO *));
 */
void
__log_region_destroy(dbenv, infop)
	DB_ENV *dbenv;
	REGINFO *infop;
{
	__db_shlocks_destroy(infop, (REGMAINT *)R_ADDR(infop,
	    ((LOG *)R_ADDR(infop, infop->rp->primary))->maint_off));

	COMPQUIET(dbenv, NULL);
	COMPQUIET(infop, NULL);
}

/*
 * __log_vtruncate
 *	This is a virtual truncate.  We set up the log indicators to
 * make everyone believe that the given record is the last one in the
 * log.  Returns with the next valid LSN (i.e., the LSN of the next
 * record to be written). This is used in replication to discard records
 * in the log file that do not agree with the master.
 *
 * PUBLIC: int __log_vtruncate __P((DB_ENV *, DB_LSN *, DB_LSN *));
 */
int
__log_vtruncate(dbenv, lsn, ckplsn)
	DB_ENV *dbenv;
	DB_LSN *lsn, *ckplsn;
{
	DBT log_dbt;
	DB_FH fh;
	DB_LOG *dblp;
	DB_LOGC *logc;
	DB_LSN end_lsn;
	LOG *lp;
	u_int32_t bytes, c_len;
	int fn, ret, t_ret;
	char *fname;

	/* Need to find out the length of this soon-to-be-last record. */
	if ((ret = dbenv->log_cursor(dbenv, &logc, 0)) != 0)
		return (ret);
	memset(&log_dbt, 0, sizeof(log_dbt));
	ret = logc->get(logc, lsn, &log_dbt, DB_SET);
	c_len = logc->c_len;
	if ((t_ret = logc->close(logc, 0)) != 0 && ret == 0)
		ret = t_ret;
	if (ret != 0)
		return (ret);

	/* Now do the truncate. */
	dblp = (DB_LOG *)dbenv->lg_handle;
	lp = (LOG *)dblp->reginfo.primary;

	R_LOCK(dbenv, &dblp->reginfo);
	end_lsn = lp->lsn;
	lp->lsn = *lsn;
	lp->len = c_len;
	lp->lsn.offset += lp->len;

	/*
	 * I am going to assume that the number of bytes written since
	 * the last checkpoint doesn't exceed a 32-bit number.
	 */
	DB_ASSERT(lp->lsn.file >= ckplsn->file);
	bytes = 0;
	if (ckplsn->file != lp->lsn.file) {
		bytes = lp->log_size - ckplsn->offset;
		if (lp->lsn.file > ckplsn->file + 1)
			bytes += lp->log_size *
			    (lp->lsn.file - ckplsn->file - 1);
		bytes += lp->lsn.offset;
	} else
		bytes = lp->lsn.offset - ckplsn->offset;

	lp->stat.st_wc_mbytes += bytes / MEGABYTE;
	lp->stat.st_wc_bytes += bytes % MEGABYTE;

	/*
	 * If the saved lsn is greater than our new end of log, reset it
	 * to our current end of log.
	 */
	if (log_compare(&lp->s_lsn, lsn) > 0)
		lp->s_lsn = lp->lsn;

	/*
	 * If the new end of log is in the middle of the buffer,
	 * don't change the w_off or f_lsn.  If the new end is
	 * before the w_off then reset w_off and f_lsn to the new
	 * end of log.
	 */
	if (lp->w_off >= lp->lsn.offset) {
		lp->f_lsn = lp->lsn;
		lp->w_off = lp->lsn.offset;
		lp->b_off = 0;
	} else
		lp->b_off = lp->lsn.offset - lp->w_off;

	ZERO_LSN(lp->waiting_lsn);
	lp->ready_lsn = lp->lsn;
	lp->wait_recs = 0;
	lp->rcvd_recs = 0;

	/* Now throw away any extra log files that we have around. */
	for (fn = lp->lsn.file + 1;; fn++) {
		if (__log_name(dblp, fn, &fname, &fh, DB_OSO_RDONLY) != 0) {
			__os_free(dbenv, fname);
			break;
		}
		(void)__os_closehandle(dbenv, &fh);
		ret = __os_unlink(dbenv, fname);
		__os_free(dbenv, fname);
		if (ret != 0)
			goto err;
	}

	/* Truncate the log to the new point. */
	if ((ret = __log_zero(dbenv, &lp->lsn, &end_lsn)) != 0)
		goto err;

err:	R_UNLOCK(dbenv, &dblp->reginfo);
	return (ret);
}

/*
 * __log_is_outdated --
 *	Used by the replication system to identify if a client's logs
 * are too old.  The log represented by dbenv is compared to the file
 * number passed in fnum.  If the log file fnum does not exist and is
 * lower-numbered than the current logs, the we return *outdatedp non
 * zero, else we return it 0.
 *
 * PUBLIC: int __log_is_outdated __P((DB_ENV *dbenv,
 * PUBLIC:     u_int32_t fnum, int *outdatedp));
 */
int
__log_is_outdated(dbenv, fnum, outdatedp)
	DB_ENV *dbenv;
	u_int32_t fnum;
	int *outdatedp;
{
	DB_LOG *dblp;
	LOG *lp;
	char *name;
	int ret;
	u_int32_t cfile;

	dblp = dbenv->lg_handle;
	*outdatedp = 0;

	if ((ret = __log_name(dblp, fnum, &name, NULL, 0)) != 0)
		return (ret);

	/* If the file exists, we're just fine. */
	if (__os_exists(name, NULL) == 0)
		goto out;

	/*
	 * It didn't exist, decide if the file number is too big or
	 * too little.  If it's too little, then we need to indicate
	 * that the LSN is outdated.
	 */
	R_LOCK(dbenv, &dblp->reginfo);
	lp = (LOG *)dblp->reginfo.primary;
	cfile = lp->lsn.file;
	R_UNLOCK(dbenv, &dblp->reginfo);

	if (cfile > fnum)
		*outdatedp = 1;
out:	__os_free(dbenv, name);
	return (ret);
}

/*
 * __log_zero --
 *	Zero out the tail of a log after a truncate.
 */
static int
__log_zero(dbenv, from_lsn, to_lsn)
	DB_ENV *dbenv;
	DB_LSN *from_lsn, *to_lsn;
{
	char *lname;
	DB_LOG *dblp;
	LOG *lp;
	int ret;
	size_t nbytes, len, nw;
	u_int8_t buf[4096];
	u_int32_t mbytes, bytes;

	dblp = dbenv->lg_handle;
	lp = (LOG *)dblp->reginfo.primary;
	lname = NULL;

	if (dblp->lfname != lp->lsn.file) {
		if (F_ISSET(&dblp->lfh, DB_FH_VALID))
			(void)__os_closehandle(dbenv, &dblp->lfh);
		dblp->lfname = lp->lsn.file;
	}

	if (from_lsn->file != to_lsn->file) {
		/* We removed some log files; have to 0 to end of file. */
		if (!F_ISSET(&dblp->lfh, DB_FH_VALID) && (ret =
		    __log_name(dblp, dblp->lfname, &lname, &dblp->lfh, 0)) != 0)
			return (ret);
		if ((ret = __os_ioinfo(dbenv,
		    NULL, &dblp->lfh, &mbytes, &bytes, NULL)) != 0)
			goto err;
		len = mbytes * MEGABYTE + bytes - from_lsn->offset;
	} else if (to_lsn->offset <= from_lsn->offset)
		return (0);
	else
		len = to_lsn->offset = from_lsn->offset;

	memset(buf, 0, sizeof(buf));

	/* Initialize the write position. */
	if (!F_ISSET(&dblp->lfh, DB_FH_VALID) &&
	    (ret = __log_name(dblp, dblp->lfname, &lname, &dblp->lfh, 0)) != 0)
		goto err;

	if ((ret = __os_seek(dbenv,
	    &dblp->lfh, 0, 0, from_lsn->offset, 0, DB_OS_SEEK_SET)) != 0)
		return (ret);

	while (len > 0) {
		nbytes = len > sizeof(buf) ? sizeof(buf) : len;
		if ((ret =
		    __os_write(dbenv, &dblp->lfh, buf, nbytes, &nw)) != 0)
			return (ret);
		len -= nbytes;
	}
err:	if (lname != NULL)
		__os_free(dbenv, lname);

	return (0);
}