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tablespace.c
tablespace.c 36.48 KiB
/*-------------------------------------------------------------------------
*
* tablespace.c
* Commands to manipulate table spaces
*
* Tablespaces in PostgreSQL are designed to allow users to determine
* where the data file(s) for a given database object reside on the file
* system.
*
* A tablespace represents a directory on the file system. At tablespace
* creation time, the directory must be empty. To simplify things and
* remove the possibility of having file name conflicts, we isolate
* files within a tablespace into database-specific subdirectories.
*
* To support file access via the information given in RelFileNode, we
* maintain a symbolic-link map in $PGDATA/pg_tblspc. The symlinks are
* named by tablespace OIDs and point to the actual tablespace directories.
* Thus the full path to an arbitrary file is
* $PGDATA/pg_tblspc/spcoid/dboid/relfilenode
*
* There are two tablespaces created at initdb time: pg_global (for shared
* tables) and pg_default (for everything else). For backwards compatibility
* and to remain functional on platforms without symlinks, these tablespaces
* are accessed specially: they are respectively
* $PGDATA/global/relfilenode
* $PGDATA/base/dboid/relfilenode
*
* To allow CREATE DATABASE to give a new database a default tablespace
* that's different from the template database's default, we make the
* provision that a zero in pg_class.reltablespace means the database's
* default tablespace. Without this, CREATE DATABASE would have to go in
* and munge the system catalogs of the new database.
*
*
* Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/tablespace.c,v 1.61 2009/01/22 20:16:02 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <unistd.h>
#include <dirent.h>
#include <sys/types.h>
#include <sys/stat.h>
#include "access/heapam.h"
#include "access/sysattr.h"
#include "access/xact.h"
#include "catalog/catalog.h"
#include "catalog/dependency.h"
#include "catalog/indexing.h"
#include "catalog/pg_tablespace.h"
#include "commands/comment.h"
#include "commands/tablespace.h"
#include "miscadmin.h"
#include "postmaster/bgwriter.h"
#include "storage/fd.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/rel.h"
#include "utils/tqual.h"
/* GUC variables */
char *default_tablespace = NULL;
char *temp_tablespaces = NULL;
static bool remove_tablespace_directories(Oid tablespaceoid, bool redo);
static void set_short_version(const char *path);
/*
* Each database using a table space is isolated into its own name space
* by a subdirectory named for the database OID. On first creation of an
* object in the tablespace, create the subdirectory. If the subdirectory
* already exists, just fall through quietly.
*
* isRedo indicates that we are creating an object during WAL replay.
* In this case we will cope with the possibility of the tablespace
* directory not being there either --- this could happen if we are
* replaying an operation on a table in a subsequently-dropped tablespace.
* We handle this by making a directory in the place where the tablespace
* symlink would normally be. This isn't an exact replay of course, but
* it's the best we can do given the available information.
*
* If tablespaces are not supported, you might think this could be a no-op,
* but you'd be wrong: we still need it in case we have to re-create a
* database subdirectory (of $PGDATA/base) during WAL replay.
*/
void
TablespaceCreateDbspace(Oid spcNode, Oid dbNode, bool isRedo)
{
struct stat st;
char *dir;
/*
* The global tablespace doesn't have per-database subdirectories, so
* nothing to do for it.
*/
if (spcNode == GLOBALTABLESPACE_OID)
return;
Assert(OidIsValid(spcNode));
Assert(OidIsValid(dbNode));
dir = GetDatabasePath(dbNode, spcNode);
if (stat(dir, &st) < 0)
{
if (errno == ENOENT)
{
/*
* Acquire TablespaceCreateLock to ensure that no DROP TABLESPACE
* or TablespaceCreateDbspace is running concurrently.
*/
LWLockAcquire(TablespaceCreateLock, LW_EXCLUSIVE);
/*
* Recheck to see if someone created the directory while we were
* waiting for lock.
*/
if (stat(dir, &st) == 0 && S_ISDIR(st.st_mode))
{
/* need not do anything */
}
else
{
/* OK, go for it */
if (mkdir(dir, S_IRWXU) < 0)
{ char *parentdir;
if (errno != ENOENT || !isRedo)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not create directory \"%s\": %m",
dir)));
/* Try to make parent directory too */
parentdir = pstrdup(dir);
get_parent_directory(parentdir);
if (mkdir(parentdir, S_IRWXU) < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not create directory \"%s\": %m",
parentdir)));
pfree(parentdir);
if (mkdir(dir, S_IRWXU) < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not create directory \"%s\": %m",
dir)));
}
}
LWLockRelease(TablespaceCreateLock);
}
else
{
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not stat directory \"%s\": %m", dir)));
}
}
else
{
/* be paranoid */
if (!S_ISDIR(st.st_mode))
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" exists but is not a directory",
dir)));
}
pfree(dir);
}
/*
* Create a table space
*
* Only superusers can create a tablespace. This seems a reasonable restriction
* since we're determining the system layout and, anyway, we probably have
* root if we're doing this kind of activity
*/
void
CreateTableSpace(CreateTableSpaceStmt *stmt)
{
#ifdef HAVE_SYMLINK
Relation rel;
Datum values[Natts_pg_tablespace];
bool nulls[Natts_pg_tablespace];
HeapTuple tuple;
Oid tablespaceoid;
char *location;
char *linkloc;
Oid ownerId;
/* Must be super user */
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), errmsg("permission denied to create tablespace \"%s\"",
stmt->tablespacename),
errhint("Must be superuser to create a tablespace.")));
/* However, the eventual owner of the tablespace need not be */
if (stmt->owner)
ownerId = get_roleid_checked(stmt->owner);
else
ownerId = GetUserId();
/* Unix-ify the offered path, and strip any trailing slashes */
location = pstrdup(stmt->location);
canonicalize_path(location);
/* disallow quotes, else CREATE DATABASE would be at risk */
if (strchr(location, '\''))
ereport(ERROR,
(errcode(ERRCODE_INVALID_NAME),
errmsg("tablespace location cannot contain single quotes")));
/*
* Allowing relative paths seems risky
*
* this also helps us ensure that location is not empty or whitespace
*/
if (!is_absolute_path(location))
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("tablespace location must be an absolute path")));
/*
* Check that location isn't too long. Remember that we're going to append
* '/<dboid>/<relid>.<nnn>' (XXX but do we ever form the whole path
* explicitly? This may be overly conservative.)
*/
if (strlen(location) >= (MAXPGPATH - 1 - 10 - 1 - 10 - 1 - 10))
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("tablespace location \"%s\" is too long",
location)));
/*
* Disallow creation of tablespaces named "pg_xxx"; we reserve this
* namespace for system purposes.
*/
if (!allowSystemTableMods && IsReservedName(stmt->tablespacename))
ereport(ERROR,
(errcode(ERRCODE_RESERVED_NAME),
errmsg("unacceptable tablespace name \"%s\"",
stmt->tablespacename),
errdetail("The prefix \"pg_\" is reserved for system tablespaces.")));
/*
* Check that there is no other tablespace by this name. (The unique
* index would catch this anyway, but might as well give a friendlier
* message.)
*/
if (OidIsValid(get_tablespace_oid(stmt->tablespacename)))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_OBJECT),
errmsg("tablespace \"%s\" already exists",
stmt->tablespacename)));
/*
* Insert tuple into pg_tablespace. The purpose of doing this first is to
* lock the proposed tablename against other would-be creators. The
* insertion will roll back if we find problems below.
*/
rel = heap_open(TableSpaceRelationId, RowExclusiveLock);
MemSet(nulls, false, sizeof(nulls));
values[Anum_pg_tablespace_spcname - 1] =
DirectFunctionCall1(namein, CStringGetDatum(stmt->tablespacename));
values[Anum_pg_tablespace_spcowner - 1] =
ObjectIdGetDatum(ownerId);
values[Anum_pg_tablespace_spclocation - 1] =
CStringGetTextDatum(location);
nulls[Anum_pg_tablespace_spcacl - 1] = true;
tuple = heap_form_tuple(rel->rd_att, values, nulls);
tablespaceoid = simple_heap_insert(rel, tuple);
CatalogUpdateIndexes(rel, tuple);
heap_freetuple(tuple);
/* Record dependency on owner */
recordDependencyOnOwner(TableSpaceRelationId, tablespaceoid, ownerId);
/*
* Attempt to coerce target directory to safe permissions. If this fails,
* it doesn't exist or has the wrong owner.
*/
if (chmod(location, 0700) != 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not set permissions on directory \"%s\": %m",
location)));
/*
* Check the target directory is empty.
*/
if (!directory_is_empty(location))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("directory \"%s\" is not empty",
location)));
/*
* Create the PG_VERSION file in the target directory. This has several
* purposes: to make sure we can write in the directory, to prevent
* someone from creating another tablespace pointing at the same directory
* (the emptiness check above will fail), and to label tablespace
* directories by PG version.
*/
set_short_version(location);
/*
* All seems well, create the symlink
*/
linkloc = (char *) palloc(10 + 10 + 1);
sprintf(linkloc, "pg_tblspc/%u", tablespaceoid);
if (symlink(location, linkloc) < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not create symbolic link \"%s\": %m",
linkloc)));
/* Record the filesystem change in XLOG */
{
xl_tblspc_create_rec xlrec;
XLogRecData rdata[2];
xlrec.ts_id = tablespaceoid;
rdata[0].data = (char *) &xlrec;
rdata[0].len = offsetof(xl_tblspc_create_rec, ts_path);
rdata[0].buffer = InvalidBuffer; rdata[0].next = &(rdata[1]);
rdata[1].data = (char *) location;
rdata[1].len = strlen(location) + 1;
rdata[1].buffer = InvalidBuffer;
rdata[1].next = NULL;
(void) XLogInsert(RM_TBLSPC_ID, XLOG_TBLSPC_CREATE, rdata);
}
/*
* Force synchronous commit, to minimize the window between creating the
* symlink on-disk and marking the transaction committed. It's not great
* that there is any window at all, but definitely we don't want to make
* it larger than necessary.
*/
ForceSyncCommit();
pfree(linkloc);
pfree(location);
/* We keep the lock on pg_tablespace until commit */
heap_close(rel, NoLock);
#else /* !HAVE_SYMLINK */
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("tablespaces are not supported on this platform")));
#endif /* HAVE_SYMLINK */
}
/*
* Drop a table space
*
* Be careful to check that the tablespace is empty.
*/
void
DropTableSpace(DropTableSpaceStmt *stmt)
{
#ifdef HAVE_SYMLINK
char *tablespacename = stmt->tablespacename;
HeapScanDesc scandesc;
Relation rel;
HeapTuple tuple;
ScanKeyData entry[1];
Oid tablespaceoid;
/*
* Find the target tuple
*/
rel = heap_open(TableSpaceRelationId, RowExclusiveLock);
ScanKeyInit(&entry[0],
Anum_pg_tablespace_spcname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(tablespacename));
scandesc = heap_beginscan(rel, SnapshotNow, 1, entry);
tuple = heap_getnext(scandesc, ForwardScanDirection);
if (!HeapTupleIsValid(tuple))
{
if (!stmt->missing_ok)
{
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("tablespace \"%s\" does not exist",
tablespacename)));
}
else
{
ereport(NOTICE, (errmsg("tablespace \"%s\" does not exist, skipping",
tablespacename)));
/* XXX I assume I need one or both of these next two calls */
heap_endscan(scandesc);
heap_close(rel, NoLock);
}
return;
}
tablespaceoid = HeapTupleGetOid(tuple);
/* Must be tablespace owner */
if (!pg_tablespace_ownercheck(tablespaceoid, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_TABLESPACE,
tablespacename);
/* Disallow drop of the standard tablespaces, even by superuser */
if (tablespaceoid == GLOBALTABLESPACE_OID ||
tablespaceoid == DEFAULTTABLESPACE_OID)
aclcheck_error(ACLCHECK_NO_PRIV, ACL_KIND_TABLESPACE,
tablespacename);
/*
* Remove the pg_tablespace tuple (this will roll back if we fail below)
*/
simple_heap_delete(rel, &tuple->t_self);
heap_endscan(scandesc);
/*
* Remove any comments on this tablespace.
*/
DeleteSharedComments(tablespaceoid, TableSpaceRelationId);
/*
* Remove dependency on owner.
*/
deleteSharedDependencyRecordsFor(TableSpaceRelationId, tablespaceoid, 0);
/*
* Acquire TablespaceCreateLock to ensure that no TablespaceCreateDbspace
* is running concurrently.
*/
LWLockAcquire(TablespaceCreateLock, LW_EXCLUSIVE);
/*
* Try to remove the physical infrastructure.
*/
if (!remove_tablespace_directories(tablespaceoid, false))
{
/*
* Not all files deleted? However, there can be lingering empty files
* in the directories, left behind by for example DROP TABLE, that
* have been scheduled for deletion at next checkpoint (see comments
* in mdunlink() for details). We could just delete them immediately,
* but we can't tell them apart from important data files that we
* mustn't delete. So instead, we force a checkpoint which will clean
* out any lingering files, and try again.
*/
RequestCheckpoint(CHECKPOINT_IMMEDIATE | CHECKPOINT_FORCE | CHECKPOINT_WAIT);
if (!remove_tablespace_directories(tablespaceoid, false))
{
/* Still not empty, the files must be important then */
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("tablespace \"%s\" is not empty",
tablespacename)));
}
}
/* Record the filesystem change in XLOG */
{
xl_tblspc_drop_rec xlrec;
XLogRecData rdata[1];
xlrec.ts_id = tablespaceoid;
rdata[0].data = (char *) &xlrec;
rdata[0].len = sizeof(xl_tblspc_drop_rec);
rdata[0].buffer = InvalidBuffer;
rdata[0].next = NULL;
(void) XLogInsert(RM_TBLSPC_ID, XLOG_TBLSPC_DROP, rdata);
}
/*
* Note: because we checked that the tablespace was empty, there should be
* no need to worry about flushing shared buffers or free space map
* entries for relations in the tablespace.
*/
/*
* Force synchronous commit, to minimize the window between removing the
* files on-disk and marking the transaction committed. It's not great
* that there is any window at all, but definitely we don't want to make
* it larger than necessary.
*/
ForceSyncCommit();
/*
* Allow TablespaceCreateDbspace again.
*/
LWLockRelease(TablespaceCreateLock);
/* We keep the lock on pg_tablespace until commit */
heap_close(rel, NoLock);
#else /* !HAVE_SYMLINK */
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("tablespaces are not supported on this platform")));
#endif /* HAVE_SYMLINK */
}
/*
* remove_tablespace_directories: attempt to remove filesystem infrastructure
*
* Returns TRUE if successful, FALSE if some subdirectory is not empty
*
* redo indicates we are redoing a drop from XLOG; okay if nothing there
*/
static bool
remove_tablespace_directories(Oid tablespaceoid, bool redo)
{
char *location;
DIR *dirdesc;
struct dirent *de;
char *subfile;
struct stat st;
location = (char *) palloc(10 + 10 + 1);
sprintf(location, "pg_tblspc/%u", tablespaceoid);
/*
* Check if the tablespace still contains any files. We try to rmdir each
* per-database directory we find in it. rmdir failure implies there are
* still files in that subdirectory, so give up. (We do not have to worry
* about undoing any already completed rmdirs, since the next attempt to
* use the tablespace from that database will simply recreate the
* subdirectory via TablespaceCreateDbspace.)
*
* Since we hold TablespaceCreateLock, no one else should be creating any * fresh subdirectories in parallel. It is possible that new files are
* being created within subdirectories, though, so the rmdir call could
* fail. Worst consequence is a less friendly error message.
*
* If redo is true then ENOENT is a likely outcome here, and we allow it
* to pass without comment. In normal operation we still allow it, but
* with a warning. This is because even though ProcessUtility disallows
* DROP TABLESPACE in a transaction block, it's possible that a previous
* DROP failed and rolled back after removing the tablespace directories
* and symlink. We want to allow a new DROP attempt to succeed at
* removing the catalog entries, so we should not give a hard error here.
*/
dirdesc = AllocateDir(location);
if (dirdesc == NULL)
{
if (errno == ENOENT)
{
if (!redo)
ereport(WARNING,
(errcode_for_file_access(),
errmsg("could not open directory \"%s\": %m",
location)));
pfree(location);
return true;
}
/* else let ReadDir report the error */
}
while ((de = ReadDir(dirdesc, location)) != NULL)
{
/* Note we ignore PG_VERSION for the nonce */
if (strcmp(de->d_name, ".") == 0 ||
strcmp(de->d_name, "..") == 0 ||
strcmp(de->d_name, "PG_VERSION") == 0)
continue;
subfile = palloc(strlen(location) + 1 + strlen(de->d_name) + 1);
sprintf(subfile, "%s/%s", location, de->d_name);
/* This check is just to deliver a friendlier error message */
if (!directory_is_empty(subfile))
{
FreeDir(dirdesc);
return false;
}
/* Do the real deed */
if (rmdir(subfile) < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not remove directory \"%s\": %m",
subfile)));
pfree(subfile);
}
FreeDir(dirdesc);
/*
* Okay, try to unlink PG_VERSION (we allow it to not be there, even in
* non-REDO case, for robustness).
*/
subfile = palloc(strlen(location) + 11 + 1);
sprintf(subfile, "%s/PG_VERSION", location);
if (unlink(subfile) < 0)
{
if (errno != ENOENT)
ereport(ERROR,
(errcode_for_file_access(), errmsg("could not remove file \"%s\": %m",
subfile)));
}
pfree(subfile);
/*
* Okay, try to remove the symlink. We must however deal with the
* possibility that it's a directory instead of a symlink --- this could
* happen during WAL replay (see TablespaceCreateDbspace), and it is also
* the normal case on Windows.
*/
if (lstat(location, &st) == 0 && S_ISDIR(st.st_mode))
{
if (rmdir(location) < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not remove directory \"%s\": %m",
location)));
}
else
{
if (unlink(location) < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not remove symbolic link \"%s\": %m",
location)));
}
pfree(location);
return true;
}
/*
* write out the PG_VERSION file in the specified directory
*/
static void
set_short_version(const char *path)
{
char *short_version;
bool gotdot = false;
int end;
char *fullname;
FILE *version_file;
/* Construct short version string (should match initdb.c) */
short_version = pstrdup(PG_VERSION);
for (end = 0; short_version[end] != '\0'; end++)
{
if (short_version[end] == '.')
{
Assert(end != 0);
if (gotdot)
break;
else
gotdot = true;
}
else if (short_version[end] < '0' || short_version[end] > '9')
{
/* gone past digits and dots */
break;
}
}
Assert(end > 0 && short_version[end - 1] != '.' && gotdot);
short_version[end] = '\0';
/* Now write the file */
fullname = palloc(strlen(path) + 11 + 1); sprintf(fullname, "%s/PG_VERSION", path);
version_file = AllocateFile(fullname, PG_BINARY_W);
if (version_file == NULL)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not write to file \"%s\": %m",
fullname)));
fprintf(version_file, "%s\n", short_version);
if (FreeFile(version_file))
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not write to file \"%s\": %m",
fullname)));
pfree(fullname);
pfree(short_version);
}
/*
* Check if a directory is empty.
*
* This probably belongs somewhere else, but not sure where...
*/
bool
directory_is_empty(const char *path)
{
DIR *dirdesc;
struct dirent *de;
dirdesc = AllocateDir(path);
while ((de = ReadDir(dirdesc, path)) != NULL)
{
if (strcmp(de->d_name, ".") == 0 ||
strcmp(de->d_name, "..") == 0)
continue;
FreeDir(dirdesc);
return false;
}
FreeDir(dirdesc);
return true;
}
/*
* Rename a tablespace
*/
void
RenameTableSpace(const char *oldname, const char *newname)
{
Relation rel;
ScanKeyData entry[1];
HeapScanDesc scan;
HeapTuple tup;
HeapTuple newtuple;
Form_pg_tablespace newform;
/* Search pg_tablespace */
rel = heap_open(TableSpaceRelationId, RowExclusiveLock);
ScanKeyInit(&entry[0],
Anum_pg_tablespace_spcname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(oldname));
scan = heap_beginscan(rel, SnapshotNow, 1, entry);
tup = heap_getnext(scan, ForwardScanDirection);
if (!HeapTupleIsValid(tup))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("tablespace \"%s\" does not exist", oldname)));
newtuple = heap_copytuple(tup);
newform = (Form_pg_tablespace) GETSTRUCT(newtuple);
heap_endscan(scan);
/* Must be owner */
if (!pg_tablespace_ownercheck(HeapTupleGetOid(newtuple), GetUserId()))
aclcheck_error(ACLCHECK_NO_PRIV, ACL_KIND_TABLESPACE, oldname);
/* Validate new name */
if (!allowSystemTableMods && IsReservedName(newname))
ereport(ERROR,
(errcode(ERRCODE_RESERVED_NAME),
errmsg("unacceptable tablespace name \"%s\"", newname),
errdetail("The prefix \"pg_\" is reserved for system tablespaces.")));
/* Make sure the new name doesn't exist */
ScanKeyInit(&entry[0],
Anum_pg_tablespace_spcname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(newname));
scan = heap_beginscan(rel, SnapshotNow, 1, entry);
tup = heap_getnext(scan, ForwardScanDirection);
if (HeapTupleIsValid(tup))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_OBJECT),
errmsg("tablespace \"%s\" already exists",
newname)));
heap_endscan(scan);
/* OK, update the entry */
namestrcpy(&(newform->spcname), newname);
simple_heap_update(rel, &newtuple->t_self, newtuple);
CatalogUpdateIndexes(rel, newtuple);
heap_close(rel, NoLock);
}
/*
* Change tablespace owner
*/
void
AlterTableSpaceOwner(const char *name, Oid newOwnerId)
{
Relation rel;
ScanKeyData entry[1];
HeapScanDesc scandesc;
Form_pg_tablespace spcForm;
HeapTuple tup;
/* Search pg_tablespace */
rel = heap_open(TableSpaceRelationId, RowExclusiveLock);
ScanKeyInit(&entry[0],
Anum_pg_tablespace_spcname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(name));
scandesc = heap_beginscan(rel, SnapshotNow, 1, entry);
tup = heap_getnext(scandesc, ForwardScanDirection);
if (!HeapTupleIsValid(tup))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("tablespace \"%s\" does not exist", name)));
spcForm = (Form_pg_tablespace) GETSTRUCT(tup);
/*
* If the new owner is the same as the existing owner, consider the
* command to have succeeded. This is for dump restoration purposes.
*/
if (spcForm->spcowner != newOwnerId)
{
Datum repl_val[Natts_pg_tablespace];
bool repl_null[Natts_pg_tablespace];
bool repl_repl[Natts_pg_tablespace];
Acl *newAcl;
Datum aclDatum;
bool isNull;
HeapTuple newtuple;
/* Otherwise, must be owner of the existing object */
if (!pg_tablespace_ownercheck(HeapTupleGetOid(tup), GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_TABLESPACE,
name);
/* Must be able to become new owner */
check_is_member_of_role(GetUserId(), newOwnerId);
/*
* Normally we would also check for create permissions here, but there
* are none for tablespaces so we follow what rename tablespace does
* and omit the create permissions check.
*
* NOTE: Only superusers may create tablespaces to begin with and so
* initially only a superuser would be able to change its ownership
* anyway.
*/
memset(repl_null, false, sizeof(repl_null));
memset(repl_repl, false, sizeof(repl_repl));
repl_repl[Anum_pg_tablespace_spcowner - 1] = true;
repl_val[Anum_pg_tablespace_spcowner - 1] = ObjectIdGetDatum(newOwnerId);
/*
* Determine the modified ACL for the new owner. This is only
* necessary when the ACL is non-null.
*/
aclDatum = heap_getattr(tup,
Anum_pg_tablespace_spcacl,
RelationGetDescr(rel),
&isNull);
if (!isNull)
{
newAcl = aclnewowner(DatumGetAclP(aclDatum),
spcForm->spcowner, newOwnerId);
repl_repl[Anum_pg_tablespace_spcacl - 1] = true;
repl_val[Anum_pg_tablespace_spcacl - 1] = PointerGetDatum(newAcl);
}
newtuple = heap_modify_tuple(tup, RelationGetDescr(rel), repl_val, repl_null, repl_repl);
simple_heap_update(rel, &newtuple->t_self, newtuple);
CatalogUpdateIndexes(rel, newtuple);
heap_freetuple(newtuple);
/* Update owner dependency reference */
changeDependencyOnOwner(TableSpaceRelationId, HeapTupleGetOid(tup),
newOwnerId);
}
heap_endscan(scandesc);
heap_close(rel, NoLock);
}
/*
* Routines for handling the GUC variable 'default_tablespace'.
*/
/* assign_hook: validate new default_tablespace, do extra actions as needed */
const char *
assign_default_tablespace(const char *newval, bool doit, GucSource source)
{
/*
* If we aren't inside a transaction, we cannot do database access so
* cannot verify the name. Must accept the value on faith.
*/
if (IsTransactionState())
{
if (newval[0] != '\0' &&
!OidIsValid(get_tablespace_oid(newval)))
{
ereport(GUC_complaint_elevel(source),
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("tablespace \"%s\" does not exist",
newval)));
return NULL;
}
}
return newval;
}
/*
* GetDefaultTablespace -- get the OID of the current default tablespace
*
* Regular objects and temporary objects have different default tablespaces,
* hence the forTemp parameter must be specified.
*
* May return InvalidOid to indicate "use the database's default tablespace".
*
* Note that caller is expected to check appropriate permissions for any
* result other than InvalidOid.
*
* This exists to hide (and possibly optimize the use of) the
* default_tablespace GUC variable.
*/
Oid
GetDefaultTablespace(bool forTemp)
{
Oid result;
/* The temp-table case is handled elsewhere */
if (forTemp)
{
PrepareTempTablespaces();
return GetNextTempTableSpace();
}
/* Fast path for default_tablespace == "" */
if (default_tablespace == NULL || default_tablespace[0] == '\0')
return InvalidOid;
/*
* It is tempting to cache this lookup for more speed, but then we would
* fail to detect the case where the tablespace was dropped since the GUC
* variable was set. Note also that we don't complain if the value fails
* to refer to an existing tablespace; we just silently return InvalidOid,
* causing the new object to be created in the database's tablespace.
*/
result = get_tablespace_oid(default_tablespace);
/*
* Allow explicit specification of database's default tablespace in * default_tablespace without triggering permissions checks.
*/
if (result == MyDatabaseTableSpace)
result = InvalidOid;
return result;
}
/*
* Routines for handling the GUC variable 'temp_tablespaces'.
*/
/* assign_hook: validate new temp_tablespaces, do extra actions as needed */
const char *
assign_temp_tablespaces(const char *newval, bool doit, GucSource source)
{
char *rawname;
List *namelist;
/* Need a modifiable copy of string */
rawname = pstrdup(newval);
/* Parse string into list of identifiers */
if (!SplitIdentifierString(rawname, ',', &namelist))
{
/* syntax error in name list */
pfree(rawname);
list_free(namelist);
return NULL;
}
/*
* If we aren't inside a transaction, we cannot do database access so
* cannot verify the individual names. Must accept the list on faith.
* Fortunately, there's then also no need to pass the data to fd.c.
*/
if (IsTransactionState())
{
/*
* If we error out below, or if we are called multiple times in one
* transaction, we'll leak a bit of TopTransactionContext memory.
* Doesn't seem worth worrying about.
*/
Oid *tblSpcs;
int numSpcs;
ListCell *l;
tblSpcs = (Oid *) MemoryContextAlloc(TopTransactionContext,
list_length(namelist) * sizeof(Oid));
numSpcs = 0;
foreach(l, namelist)
{
char *curname = (char *) lfirst(l);
Oid curoid;
AclResult aclresult;
/* Allow an empty string (signifying database default) */
if (curname[0] == '\0')
{
tblSpcs[numSpcs++] = InvalidOid;
continue;
}
/* Else verify that name is a valid tablespace name */
curoid = get_tablespace_oid(curname);
if (curoid == InvalidOid)
{
/*
* In an interactive SET command, we ereport for bad info.
* Otherwise, silently ignore any bad list elements. */
if (source >= PGC_S_INTERACTIVE)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("tablespace \"%s\" does not exist",
curname)));
continue;
}
/*
* Allow explicit specification of database's default tablespace
* in temp_tablespaces without triggering permissions checks.
*/
if (curoid == MyDatabaseTableSpace)
{
tblSpcs[numSpcs++] = InvalidOid;
continue;
}
/* Check permissions similarly */
aclresult = pg_tablespace_aclcheck(curoid, GetUserId(),
ACL_CREATE);
if (aclresult != ACLCHECK_OK)
{
if (source >= PGC_S_INTERACTIVE)
aclcheck_error(aclresult, ACL_KIND_TABLESPACE, curname);
continue;
}
tblSpcs[numSpcs++] = curoid;
}
/* If actively "doing it", give the new list to fd.c */
if (doit)
SetTempTablespaces(tblSpcs, numSpcs);
else
pfree(tblSpcs);
}
pfree(rawname);
list_free(namelist);
return newval;
}
/*
* PrepareTempTablespaces -- prepare to use temp tablespaces
*
* If we have not already done so in the current transaction, parse the
* temp_tablespaces GUC variable and tell fd.c which tablespace(s) to use
* for temp files.
*/
void
PrepareTempTablespaces(void)
{
char *rawname;
List *namelist;
Oid *tblSpcs;
int numSpcs;
ListCell *l;
/* No work if already done in current transaction */
if (TempTablespacesAreSet())
return;
/*
* Can't do catalog access unless within a transaction. This is just a
* safety check in case this function is called by low-level code that
* could conceivably execute outside a transaction. Note that in such a
* scenario, fd.c will fall back to using the current database's default * tablespace, which should always be OK.
*/
if (!IsTransactionState())
return;
/* Need a modifiable copy of string */
rawname = pstrdup(temp_tablespaces);
/* Parse string into list of identifiers */
if (!SplitIdentifierString(rawname, ',', &namelist))
{
/* syntax error in name list */
SetTempTablespaces(NULL, 0);
pfree(rawname);
list_free(namelist);
return;
}
/* Store tablespace OIDs in an array in TopTransactionContext */
tblSpcs = (Oid *) MemoryContextAlloc(TopTransactionContext,
list_length(namelist) * sizeof(Oid));
numSpcs = 0;
foreach(l, namelist)
{
char *curname = (char *) lfirst(l);
Oid curoid;
AclResult aclresult;
/* Allow an empty string (signifying database default) */
if (curname[0] == '\0')
{
tblSpcs[numSpcs++] = InvalidOid;
continue;
}
/* Else verify that name is a valid tablespace name */
curoid = get_tablespace_oid(curname);
if (curoid == InvalidOid)
{
/* Silently ignore any bad list elements */
continue;
}
/*
* Allow explicit specification of database's default tablespace in
* temp_tablespaces without triggering permissions checks.
*/
if (curoid == MyDatabaseTableSpace)
{
tblSpcs[numSpcs++] = InvalidOid;
continue;
}
/* Check permissions similarly */
aclresult = pg_tablespace_aclcheck(curoid, GetUserId(),
ACL_CREATE);
if (aclresult != ACLCHECK_OK)
continue;
tblSpcs[numSpcs++] = curoid;
}
SetTempTablespaces(tblSpcs, numSpcs);
pfree(rawname);
list_free(namelist);
}
/* * get_tablespace_oid - given a tablespace name, look up the OID
*
* Returns InvalidOid if tablespace name not found.
*/
Oid
get_tablespace_oid(const char *tablespacename)
{
Oid result;
Relation rel;
HeapScanDesc scandesc;
HeapTuple tuple;
ScanKeyData entry[1];
/*
* Search pg_tablespace. We use a heapscan here even though there is an
* index on name, on the theory that pg_tablespace will usually have just
* a few entries and so an indexed lookup is a waste of effort.
*/
rel = heap_open(TableSpaceRelationId, AccessShareLock);
ScanKeyInit(&entry[0],
Anum_pg_tablespace_spcname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(tablespacename));
scandesc = heap_beginscan(rel, SnapshotNow, 1, entry);
tuple = heap_getnext(scandesc, ForwardScanDirection);
/* We assume that there can be at most one matching tuple */
if (HeapTupleIsValid(tuple))
result = HeapTupleGetOid(tuple);
else
result = InvalidOid;
heap_endscan(scandesc);
heap_close(rel, AccessShareLock);
return result;
}
/*
* get_tablespace_name - given a tablespace OID, look up the name
*
* Returns a palloc'd string, or NULL if no such tablespace.
*/
char *
get_tablespace_name(Oid spc_oid)
{
char *result;
Relation rel;
HeapScanDesc scandesc;
HeapTuple tuple;
ScanKeyData entry[1];
/*
* Search pg_tablespace. We use a heapscan here even though there is an
* index on oid, on the theory that pg_tablespace will usually have just a
* few entries and so an indexed lookup is a waste of effort.
*/
rel = heap_open(TableSpaceRelationId, AccessShareLock);
ScanKeyInit(&entry[0],
ObjectIdAttributeNumber,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(spc_oid));
scandesc = heap_beginscan(rel, SnapshotNow, 1, entry);
tuple = heap_getnext(scandesc, ForwardScanDirection);
/* We assume that there can be at most one matching tuple */
if (HeapTupleIsValid(tuple))
result = pstrdup(NameStr(((Form_pg_tablespace) GETSTRUCT(tuple))->spcname)); else
result = NULL;
heap_endscan(scandesc);
heap_close(rel, AccessShareLock);
return result;
}
/*
* TABLESPACE resource manager's routines
*/
void
tblspc_redo(XLogRecPtr lsn, XLogRecord *record)
{
uint8 info = record->xl_info & ~XLR_INFO_MASK;
/* Backup blocks are not used in tblspc records */
Assert(!(record->xl_info & XLR_BKP_BLOCK_MASK));
if (info == XLOG_TBLSPC_CREATE)
{
xl_tblspc_create_rec *xlrec = (xl_tblspc_create_rec *) XLogRecGetData(record);
char *location = xlrec->ts_path;
char *linkloc;
/*
* Attempt to coerce target directory to safe permissions. If this
* fails, it doesn't exist or has the wrong owner.
*/
if (chmod(location, 0700) != 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not set permissions on directory \"%s\": %m",
location)));
/* Create or re-create the PG_VERSION file in the target directory */
set_short_version(location);
/* Create the symlink if not already present */
linkloc = (char *) palloc(10 + 10 + 1);
sprintf(linkloc, "pg_tblspc/%u", xlrec->ts_id);
if (symlink(location, linkloc) < 0)
{
if (errno != EEXIST)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not create symbolic link \"%s\": %m",
linkloc)));
}
pfree(linkloc);
}
else if (info == XLOG_TBLSPC_DROP)
{
xl_tblspc_drop_rec *xlrec = (xl_tblspc_drop_rec *) XLogRecGetData(record);
if (!remove_tablespace_directories(xlrec->ts_id, true))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("tablespace %u is not empty",
xlrec->ts_id)));
}
else
elog(PANIC, "tblspc_redo: unknown op code %u", info);
}
voidtblspc_desc(StringInfo buf, uint8 xl_info, char *rec)
{
uint8 info = xl_info & ~XLR_INFO_MASK;
if (info == XLOG_TBLSPC_CREATE)
{
xl_tblspc_create_rec *xlrec = (xl_tblspc_create_rec *) rec;
appendStringInfo(buf, "create ts: %u \"%s\"",
xlrec->ts_id, xlrec->ts_path);
}
else if (info == XLOG_TBLSPC_DROP)
{
xl_tblspc_drop_rec *xlrec = (xl_tblspc_drop_rec *) rec;
appendStringInfo(buf, "drop ts: %u", xlrec->ts_id);
}
else
appendStringInfo(buf, "UNKNOWN");
}