Add new function BackgroundWorkerInitializeConnectionByOid.

Sometimes it's useful for a background worker to be able to initialize
its database connection by OID rather than by name, so provide a way
to do that.
This commit is contained in:
Robert Haas 2015-02-02 16:23:59 -05:00
parent 2488eff889
commit 5d2f957f3f
9 changed files with 56 additions and 22 deletions

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@ -146,14 +146,17 @@ typedef struct BackgroundWorker
</para>
<para>Once running, the process can connect to a database by calling
<function>BackgroundWorkerInitializeConnection(<parameter>char *dbname</parameter>, <parameter>char *username</parameter>)</function>.
<function>BackgroundWorkerInitializeConnection(<parameter>char *dbname</parameter>, <parameter>char *username</parameter>)</function> or
<function>BackgroundWorkerInitializeConnectionByOid(<parameter>Oid dboid</parameter>, <parameter>Oid useroid</parameter>)</function>.
This allows the process to run transactions and queries using the
<literal>SPI</literal> interface. If <varname>dbname</> is NULL,
the session is not connected to any particular database, but shared catalogs
can be accessed. If <varname>username</> is NULL, the process will run as
the superuser created during <command>initdb</>.
BackgroundWorkerInitializeConnection can only be called once per background
process, it is not possible to switch databases.
<literal>SPI</literal> interface. If <varname>dbname</> is NULL or
<varname>dboid</> is <literal>InvalidOid</>, the session is not connected
to any particular database, but shared catalogs can be accessed.
If <varname>username</> is NULL or <varname>useroid</> is
<literal>InvalidOid</>, the process will run as the superuser created
during <command>initdb</>.
A background worker can only call one of these two functions, and only
once. It is not possible to switch databases.
</para>
<para>

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@ -467,7 +467,7 @@ BootstrapModeMain(void)
*/
InitProcess();
InitPostgres(NULL, InvalidOid, NULL, NULL);
InitPostgres(NULL, InvalidOid, NULL, InvalidOid, NULL);
/* Initialize stuff for bootstrap-file processing */
for (i = 0; i < MAXATTR; i++)

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@ -450,7 +450,7 @@ AutoVacLauncherMain(int argc, char *argv[])
InitProcess();
#endif
InitPostgres(NULL, InvalidOid, NULL, NULL);
InitPostgres(NULL, InvalidOid, NULL, InvalidOid, NULL);
SetProcessingMode(NormalProcessing);
@ -1620,7 +1620,7 @@ AutoVacWorkerMain(int argc, char *argv[])
* Note: if we have selected a just-deleted database (due to using
* stale stats info), we'll fail and exit here.
*/
InitPostgres(NULL, dbid, NULL, dbname);
InitPostgres(NULL, dbid, NULL, InvalidOid, dbname);
SetProcessingMode(NormalProcessing);
set_ps_display(dbname, false);
ereport(DEBUG1,

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@ -5313,7 +5313,30 @@ BackgroundWorkerInitializeConnection(char *dbname, char *username)
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("database connection requirement not indicated during registration")));
InitPostgres(dbname, InvalidOid, username, NULL);
InitPostgres(dbname, InvalidOid, username, InvalidOid, NULL);
/* it had better not gotten out of "init" mode yet */
if (!IsInitProcessingMode())
ereport(ERROR,
(errmsg("invalid processing mode in background worker")));
SetProcessingMode(NormalProcessing);
}
/*
* Connect background worker to a database using OIDs.
*/
void
BackgroundWorkerInitializeConnectionByOid(Oid dboid, Oid useroid)
{
BackgroundWorker *worker = MyBgworkerEntry;
/* XXX is this the right errcode? */
if (!(worker->bgw_flags & BGWORKER_BACKEND_DATABASE_CONNECTION))
ereport(FATAL,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("database connection requirement not indicated during registration")));
InitPostgres(NULL, dboid, NULL, useroid, NULL);
/* it had better not gotten out of "init" mode yet */
if (!IsInitProcessingMode())

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@ -3714,7 +3714,7 @@ PostgresMain(int argc, char *argv[],
* it inside InitPostgres() instead. In particular, anything that
* involves database access should be there, not here.
*/
InitPostgres(dbname, InvalidOid, username, NULL);
InitPostgres(dbname, InvalidOid, username, InvalidOid, NULL);
/*
* If the PostmasterContext is still around, recycle the space; we don't

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@ -453,11 +453,10 @@ has_rolreplication(Oid roleid)
* Initialize user identity during normal backend startup
*/
void
InitializeSessionUserId(const char *rolename)
InitializeSessionUserId(const char *rolename, Oid roleid)
{
HeapTuple roleTup;
Form_pg_authid rform;
Oid roleid;
/*
* Don't do scans if we're bootstrapping, none of the system catalogs
@ -468,7 +467,10 @@ InitializeSessionUserId(const char *rolename)
/* call only once */
AssertState(!OidIsValid(AuthenticatedUserId));
if (rolename != NULL)
roleTup = SearchSysCache1(AUTHNAME, PointerGetDatum(rolename));
else
roleTup = SearchSysCache1(AUTHOID, ObjectIdGetDatum(roleid));
if (!HeapTupleIsValid(roleTup))
ereport(FATAL,
(errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),

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@ -523,6 +523,9 @@ BaseInit(void)
* name can be returned to the caller in out_dbname. If out_dbname isn't
* NULL, it must point to a buffer of size NAMEDATALEN.
*
* Similarly, the username can be passed by name, using the username parameter,
* or by OID using the useroid parameter.
*
* In bootstrap mode no parameters are used. The autovacuum launcher process
* doesn't use any parameters either, because it only goes far enough to be
* able to read pg_database; it doesn't connect to any particular database.
@ -537,7 +540,7 @@ BaseInit(void)
*/
void
InitPostgres(const char *in_dbname, Oid dboid, const char *username,
char *out_dbname)
Oid useroid, char *out_dbname)
{
bool bootstrap = IsBootstrapProcessingMode();
bool am_superuser;
@ -692,18 +695,18 @@ InitPostgres(const char *in_dbname, Oid dboid, const char *username,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("no roles are defined in this database system"),
errhint("You should immediately run CREATE USER \"%s\" SUPERUSER;.",
username)));
username != NULL ? username : "postgres")));
}
else if (IsBackgroundWorker)
{
if (username == NULL)
if (username == NULL && !OidIsValid(useroid))
{
InitializeSessionUserIdStandalone();
am_superuser = true;
}
else
{
InitializeSessionUserId(username);
InitializeSessionUserId(username, useroid);
am_superuser = superuser();
}
}
@ -712,7 +715,7 @@ InitPostgres(const char *in_dbname, Oid dboid, const char *username,
/* normal multiuser case */
Assert(MyProcPort != NULL);
PerformAuthentication(MyProcPort);
InitializeSessionUserId(username);
InitializeSessionUserId(username, useroid);
am_superuser = superuser();
}

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@ -307,7 +307,7 @@ extern bool InLocalUserIdChange(void);
extern bool InSecurityRestrictedOperation(void);
extern void GetUserIdAndContext(Oid *userid, bool *sec_def_context);
extern void SetUserIdAndContext(Oid userid, bool sec_def_context);
extern void InitializeSessionUserId(const char *rolename);
extern void InitializeSessionUserId(const char *rolename, Oid useroid);
extern void InitializeSessionUserIdStandalone(void);
extern void SetSessionAuthorization(Oid userid, bool is_superuser);
extern Oid GetCurrentRoleId(void);
@ -411,7 +411,7 @@ extern AuxProcType MyAuxProcType;
extern void pg_split_opts(char **argv, int *argcp, char *optstr);
extern void InitializeMaxBackends(void);
extern void InitPostgres(const char *in_dbname, Oid dboid, const char *username,
char *out_dbname);
Oid useroid, char *out_dbname);
extern void BaseInit(void);
/* in utils/init/miscinit.c */

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@ -130,6 +130,9 @@ extern PGDLLIMPORT BackgroundWorker *MyBgworkerEntry;
*/
extern void BackgroundWorkerInitializeConnection(char *dbname, char *username);
/* Just like the above, but specifying database and user by OID. */
extern void BackgroundWorkerInitializeConnectionByOid(Oid dboid, Oid useroid);
/* Block/unblock signals in a background worker process */
extern void BackgroundWorkerBlockSignals(void);
extern void BackgroundWorkerUnblockSignals(void);