xa.c
上传用户:romrleung
上传日期:2022-05-23
资源大小:18897k
文件大小:13k
- /*-
- * See the file LICENSE for redistribution information.
- *
- * Copyright (c) 1998-2002
- * Sleepycat Software. All rights reserved.
- */
- #include "db_config.h"
- #ifndef lint
- static const char revid[] = "$Id: xa.c,v 11.23 2002/08/29 14:22:25 margo Exp $";
- #endif /* not lint */
- #ifndef NO_SYSTEM_INCLUDES
- #include <sys/types.h>
- #include <stdlib.h>
- #include <string.h>
- #endif
- #include "db_int.h"
- #include "dbinc/txn.h"
- static int __db_xa_close __P((char *, int, long));
- static int __db_xa_commit __P((XID *, int, long));
- static int __db_xa_complete __P((int *, int *, int, long));
- static int __db_xa_end __P((XID *, int, long));
- static int __db_xa_forget __P((XID *, int, long));
- static int __db_xa_open __P((char *, int, long));
- static int __db_xa_prepare __P((XID *, int, long));
- static int __db_xa_recover __P((XID *, long, int, long));
- static int __db_xa_rollback __P((XID *, int, long));
- static int __db_xa_start __P((XID *, int, long));
- static void __xa_txn_end __P((DB_TXN *));
- /*
- * Possible flag values:
- * Dynamic registration 0 => no dynamic registration
- * TMREGISTER => dynamic registration
- * Asynchronous operation 0 => no support for asynchrony
- * TMUSEASYNC => async support
- * Migration support 0 => migration of transactions across
- * threads is possible
- * TMNOMIGRATE => no migration across threads
- */
- const struct xa_switch_t db_xa_switch = {
- "Berkeley DB", /* name[RMNAMESZ] */
- TMNOMIGRATE, /* flags */
- 0, /* version */
- __db_xa_open, /* xa_open_entry */
- __db_xa_close, /* xa_close_entry */
- __db_xa_start, /* xa_start_entry */
- __db_xa_end, /* xa_end_entry */
- __db_xa_rollback, /* xa_rollback_entry */
- __db_xa_prepare, /* xa_prepare_entry */
- __db_xa_commit, /* xa_commit_entry */
- __db_xa_recover, /* xa_recover_entry */
- __db_xa_forget, /* xa_forget_entry */
- __db_xa_complete /* xa_complete_entry */
- };
- /*
- * __db_xa_open --
- * The open call in the XA protocol. The rmid field is an id number
- * that the TM assigned us and will pass us on every xa call. We need to
- * map that rmid number into a dbenv structure that we create during
- * initialization. Since this id number is thread specific, we do not
- * need to store it in shared memory. The file xa_map.c implements all
- * such xa->db mappings.
- * The xa_info field is instance specific information. We require
- * that the value of DB_HOME be passed in xa_info. Since xa_info is the
- * only thing that we get to pass to db_env_create, any config information
- * will have to be done via a config file instead of via the db_env_create
- * call.
- */
- static int
- __db_xa_open(xa_info, rmid, flags)
- char *xa_info;
- int rmid;
- long flags;
- {
- DB_ENV *env;
- if (LF_ISSET(TMASYNC))
- return (XAER_ASYNC);
- if (flags != TMNOFLAGS)
- return (XAER_INVAL);
- /* Verify if we already have this environment open. */
- if (__db_rmid_to_env(rmid, &env) == 0)
- return (XA_OK);
- if (__os_calloc(env, 1, sizeof(DB_ENV), &env) != 0)
- return (XAER_RMERR);
- /* Open a new environment. */
- #define XA_FLAGS
- DB_CREATE | DB_INIT_LOCK | DB_INIT_LOG | DB_INIT_MPOOL | DB_INIT_TXN
- if (db_env_create(&env, 0) != 0)
- return (XAER_RMERR);
- if (env->open(env, xa_info, XA_FLAGS, 0) != 0)
- goto err;
- /* Create the mapping. */
- if (__db_map_rmid(rmid, env) != 0)
- goto err;
- /* Allocate space for the current transaction. */
- if (__os_calloc(env, 1, sizeof(DB_TXN), &env->xa_txn) != 0)
- goto err;
- env->xa_txn->txnid = TXN_INVALID;
- return (XA_OK);
- err: (void)env->close(env, 0);
- return (XAER_RMERR);
- }
- /*
- * __db_xa_close --
- * The close call of the XA protocol. The only trickiness here
- * is that if there are any active transactions, we must fail. It is
- * *not* an error to call close on an environment that has already been
- * closed (I am interpreting that to mean it's OK to call close on an
- * environment that has never been opened).
- */
- static int
- __db_xa_close(xa_info, rmid, flags)
- char *xa_info;
- int rmid;
- long flags;
- {
- DB_ENV *env;
- int ret, t_ret;
- COMPQUIET(xa_info, NULL);
- if (LF_ISSET(TMASYNC))
- return (XAER_ASYNC);
- if (flags != TMNOFLAGS)
- return (XAER_INVAL);
- /* If the environment is closed, then we're done. */
- if (__db_rmid_to_env(rmid, &env) != 0)
- return (XA_OK);
- /* Check if there are any pending transactions. */
- if (env->xa_txn != NULL && env->xa_txn->txnid != TXN_INVALID)
- return (XAER_PROTO);
- /* Destroy the mapping. */
- ret = __db_unmap_rmid(rmid);
- /* Discard space held for the current transaction. */
- if (env->xa_txn != NULL)
- __os_free(env, env->xa_txn);
- /* Close the environment. */
- if ((t_ret = env->close(env, 0)) != 0 && ret == 0)
- ret = t_ret;
- return (ret == 0 ? XA_OK : XAER_RMERR);
- }
- /*
- * __db_xa_start --
- * Begin a transaction for the current resource manager.
- */
- static int
- __db_xa_start(xid, rmid, flags)
- XID *xid;
- int rmid;
- long flags;
- {
- DB_ENV *env;
- TXN_DETAIL *td;
- size_t off;
- int is_known;
- #define OK_FLAGS (TMJOIN | TMRESUME | TMNOWAIT | TMASYNC | TMNOFLAGS)
- if (LF_ISSET(~OK_FLAGS))
- return (XAER_INVAL);
- if (LF_ISSET(TMJOIN) && LF_ISSET(TMRESUME))
- return (XAER_INVAL);
- if (LF_ISSET(TMASYNC))
- return (XAER_ASYNC);
- if (__db_rmid_to_env(rmid, &env) != 0)
- return (XAER_PROTO);
- is_known = __db_xid_to_txn(env, xid, &off) == 0;
- if (is_known && !LF_ISSET(TMRESUME) && !LF_ISSET(TMJOIN))
- return (XAER_DUPID);
- if (!is_known && LF_ISSET(TMRESUME | TMJOIN))
- return (XAER_NOTA);
- /*
- * This can't block, so we can ignore TMNOWAIT.
- *
- * Other error conditions: RMERR, RMFAIL, OUTSIDE, PROTO, RB*
- */
- if (is_known) {
- td = (TXN_DETAIL *)
- R_ADDR(&((DB_TXNMGR *)env->tx_handle)->reginfo, off);
- if (td->xa_status == TXN_XA_SUSPENDED &&
- !LF_ISSET(TMRESUME | TMJOIN))
- return (XAER_PROTO);
- if (td->xa_status == TXN_XA_DEADLOCKED)
- return (XA_RBDEADLOCK);
- if (td->xa_status == TXN_XA_ABORTED)
- return (XA_RBOTHER);
- /* Now, fill in the global transaction structure. */
- __txn_continue(env, env->xa_txn, td, off);
- td->xa_status = TXN_XA_STARTED;
- } else {
- if (__txn_xa_begin(env, env->xa_txn) != 0)
- return (XAER_RMERR);
- (void)__db_map_xid(env, xid, env->xa_txn->off);
- td = (TXN_DETAIL *)
- R_ADDR(&((DB_TXNMGR *)env->tx_handle)->reginfo,
- env->xa_txn->off);
- td->xa_status = TXN_XA_STARTED;
- }
- return (XA_OK);
- }
- /*
- * __db_xa_end --
- * Disassociate the current transaction from the current process.
- */
- static int
- __db_xa_end(xid, rmid, flags)
- XID *xid;
- int rmid;
- long flags;
- {
- DB_ENV *env;
- DB_TXN *txn;
- TXN_DETAIL *td;
- size_t off;
- if (flags != TMNOFLAGS && !LF_ISSET(TMSUSPEND | TMSUCCESS | TMFAIL))
- return (XAER_INVAL);
- if (__db_rmid_to_env(rmid, &env) != 0)
- return (XAER_PROTO);
- if (__db_xid_to_txn(env, xid, &off) != 0)
- return (XAER_NOTA);
- txn = env->xa_txn;
- if (off != txn->off)
- return (XAER_PROTO);
- td = (TXN_DETAIL *)R_ADDR(&((DB_TXNMGR *)env->tx_handle)->reginfo, off);
- if (td->xa_status == TXN_XA_DEADLOCKED)
- return (XA_RBDEADLOCK);
- if (td->status == TXN_ABORTED)
- return (XA_RBOTHER);
- if (td->xa_status != TXN_XA_STARTED)
- return (XAER_PROTO);
- /* Update the shared memory last_lsn field */
- td->last_lsn = txn->last_lsn;
- /*
- * If we ever support XA migration, we cannot keep SUSPEND/END
- * status in the shared region; it would have to be process local.
- */
- if (LF_ISSET(TMSUSPEND))
- td->xa_status = TXN_XA_SUSPENDED;
- else
- td->xa_status = TXN_XA_ENDED;
- txn->txnid = TXN_INVALID;
- return (XA_OK);
- }
- /*
- * __db_xa_prepare --
- * Sync the log to disk so we can guarantee recoverability.
- */
- static int
- __db_xa_prepare(xid, rmid, flags)
- XID *xid;
- int rmid;
- long flags;
- {
- DB_ENV *env;
- TXN_DETAIL *td;
- size_t off;
- if (LF_ISSET(TMASYNC))
- return (XAER_ASYNC);
- if (flags != TMNOFLAGS)
- return (XAER_INVAL);
- /*
- * We need to know if we've ever called prepare on this.
- * As part of the prepare, we set the xa_status field to
- * reflect that fact that prepare has been called, and if
- * it's ever called again, it's an error.
- */
- if (__db_rmid_to_env(rmid, &env) != 0)
- return (XAER_PROTO);
- if (__db_xid_to_txn(env, xid, &off) != 0)
- return (XAER_NOTA);
- td = (TXN_DETAIL *)R_ADDR(&((DB_TXNMGR *)env->tx_handle)->reginfo, off);
- if (td->xa_status == TXN_XA_DEADLOCKED)
- return (XA_RBDEADLOCK);
- if (td->xa_status != TXN_XA_ENDED && td->xa_status != TXN_XA_SUSPENDED)
- return (XAER_PROTO);
- /* Now, fill in the global transaction structure. */
- __txn_continue(env, env->xa_txn, td, off);
- if (env->xa_txn->prepare(env->xa_txn, (u_int8_t *)xid->data) != 0)
- return (XAER_RMERR);
- td->xa_status = TXN_XA_PREPARED;
- /* No fatal value that would require an XAER_RMFAIL. */
- __xa_txn_end(env->xa_txn);
- return (XA_OK);
- }
- /*
- * __db_xa_commit --
- * Commit the transaction
- */
- static int
- __db_xa_commit(xid, rmid, flags)
- XID *xid;
- int rmid;
- long flags;
- {
- DB_ENV *env;
- TXN_DETAIL *td;
- size_t off;
- if (LF_ISSET(TMASYNC))
- return (XAER_ASYNC);
- #undef OK_FLAGS
- #define OK_FLAGS (TMNOFLAGS | TMNOWAIT | TMONEPHASE)
- if (LF_ISSET(~OK_FLAGS))
- return (XAER_INVAL);
- /*
- * We need to know if we've ever called prepare on this.
- * We can verify this by examining the xa_status field.
- */
- if (__db_rmid_to_env(rmid, &env) != 0)
- return (XAER_PROTO);
- if (__db_xid_to_txn(env, xid, &off) != 0)
- return (XAER_NOTA);
- td = (TXN_DETAIL *)R_ADDR(&((DB_TXNMGR *)env->tx_handle)->reginfo, off);
- if (td->xa_status == TXN_XA_DEADLOCKED)
- return (XA_RBDEADLOCK);
- if (td->xa_status == TXN_XA_ABORTED)
- return (XA_RBOTHER);
- if (LF_ISSET(TMONEPHASE) &&
- td->xa_status != TXN_XA_ENDED && td->xa_status != TXN_XA_SUSPENDED)
- return (XAER_PROTO);
- if (!LF_ISSET(TMONEPHASE) && td->xa_status != TXN_XA_PREPARED)
- return (XAER_PROTO);
- /* Now, fill in the global transaction structure. */
- __txn_continue(env, env->xa_txn, td, off);
- if (env->xa_txn->commit(env->xa_txn, 0) != 0)
- return (XAER_RMERR);
- /* No fatal value that would require an XAER_RMFAIL. */
- __xa_txn_end(env->xa_txn);
- return (XA_OK);
- }
- /*
- * __db_xa_recover --
- * Returns a list of prepared and heuristically completed transactions.
- *
- * The return value is the number of xids placed into the xid array (less
- * than or equal to the count parameter). The flags are going to indicate
- * whether we are starting a scan or continuing one.
- */
- static int
- __db_xa_recover(xids, count, rmid, flags)
- XID *xids;
- long count, flags;
- int rmid;
- {
- DB_ENV *env;
- u_int32_t newflags;
- long rval;
- /* If the environment is closed, then we're done. */
- if (__db_rmid_to_env(rmid, &env) != 0)
- return (XAER_PROTO);
- if (LF_ISSET(TMSTARTRSCAN))
- newflags = DB_FIRST;
- else if (LF_ISSET(TMENDRSCAN))
- newflags = DB_LAST;
- else
- newflags = DB_NEXT;
- rval = 0;
- if (__txn_get_prepared(env, xids, NULL, count, &rval, newflags) != 0)
- return (XAER_RMERR);
- else
- return (rval);
- }
- /*
- * __db_xa_rollback
- * Abort an XA transaction.
- */
- static int
- __db_xa_rollback(xid, rmid, flags)
- XID *xid;
- int rmid;
- long flags;
- {
- DB_ENV *env;
- TXN_DETAIL *td;
- size_t off;
- if (LF_ISSET(TMASYNC))
- return (XAER_ASYNC);
- if (flags != TMNOFLAGS)
- return (XAER_INVAL);
- if (__db_rmid_to_env(rmid, &env) != 0)
- return (XAER_PROTO);
- if (__db_xid_to_txn(env, xid, &off) != 0)
- return (XAER_NOTA);
- td = (TXN_DETAIL *)R_ADDR(&((DB_TXNMGR *)env->tx_handle)->reginfo, off);
- if (td->xa_status == TXN_XA_DEADLOCKED)
- return (XA_RBDEADLOCK);
- if (td->xa_status == TXN_XA_ABORTED)
- return (XA_RBOTHER);
- if (td->xa_status != TXN_XA_ENDED && td->xa_status != TXN_XA_SUSPENDED
- && td->xa_status != TXN_XA_PREPARED)
- return (XAER_PROTO);
- /* Now, fill in the global transaction structure. */
- __txn_continue(env, env->xa_txn, td, off);
- if (env->xa_txn->abort(env->xa_txn) != 0)
- return (XAER_RMERR);
- /* No fatal value that would require an XAER_RMFAIL. */
- __xa_txn_end(env->xa_txn);
- return (XA_OK);
- }
- /*
- * __db_xa_forget --
- * Forget about an XID for a transaction that was heuristically
- * completed. Since we do not heuristically complete anything, I
- * don't think we have to do anything here, but we should make sure
- * that we reclaim the slots in the txnid table.
- */
- static int
- __db_xa_forget(xid, rmid, flags)
- XID *xid;
- int rmid;
- long flags;
- {
- DB_ENV *env;
- size_t off;
- if (LF_ISSET(TMASYNC))
- return (XAER_ASYNC);
- if (flags != TMNOFLAGS)
- return (XAER_INVAL);
- if (__db_rmid_to_env(rmid, &env) != 0)
- return (XAER_PROTO);
- /*
- * If mapping is gone, then we're done.
- */
- if (__db_xid_to_txn(env, xid, &off) != 0)
- return (XA_OK);
- __db_unmap_xid(env, xid, off);
- /* No fatal value that would require an XAER_RMFAIL. */
- return (XA_OK);
- }
- /*
- * __db_xa_complete --
- * Used to wait for asynchronous operations to complete. Since we're
- * not doing asynch, this is an invalid operation.
- */
- static int
- __db_xa_complete(handle, retval, rmid, flags)
- int *handle, *retval, rmid;
- long flags;
- {
- COMPQUIET(handle, NULL);
- COMPQUIET(retval, NULL);
- COMPQUIET(rmid, 0);
- COMPQUIET(flags, 0);
- return (XAER_INVAL);
- }
- /*
- * __xa_txn_end --
- * Invalidate a transaction structure that was generated by __txn_continue.
- */
- static void
- __xa_txn_end(txn)
- DB_TXN *txn;
- {
- if (txn != NULL)
- txn->txnid = TXN_INVALID;
- }