mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-12-09 08:10:09 +08:00
97c39498e5
Backpatch-through: certain files through 9.4
491 lines
12 KiB
C
491 lines
12 KiB
C
/*-------------------------------------------------------------------------
|
|
*
|
|
* heapfuncs.c
|
|
* Functions to investigate heap pages
|
|
*
|
|
* We check the input to these functions for corrupt pointers etc. that
|
|
* might cause crashes, but at the same time we try to print out as much
|
|
* information as possible, even if it's nonsense. That's because if a
|
|
* page is corrupt, we don't know why and how exactly it is corrupt, so we
|
|
* let the user judge it.
|
|
*
|
|
* These functions are restricted to superusers for the fear of introducing
|
|
* security holes if the input checking isn't as water-tight as it should be.
|
|
* You'd need to be superuser to obtain a raw page image anyway, so
|
|
* there's hardly any use case for using these without superuser-rights
|
|
* anyway.
|
|
*
|
|
* Copyright (c) 2007-2019, PostgreSQL Global Development Group
|
|
*
|
|
* IDENTIFICATION
|
|
* contrib/pageinspect/heapfuncs.c
|
|
*
|
|
*-------------------------------------------------------------------------
|
|
*/
|
|
|
|
#include "postgres.h"
|
|
|
|
#include "pageinspect.h"
|
|
|
|
#include "access/htup_details.h"
|
|
#include "funcapi.h"
|
|
#include "catalog/pg_type.h"
|
|
#include "miscadmin.h"
|
|
#include "utils/array.h"
|
|
#include "utils/builtins.h"
|
|
#include "utils/rel.h"
|
|
|
|
/*
|
|
* It's not supported to create tuples with oids anymore, but when pg_upgrade
|
|
* was used to upgrade from an older version, tuples might still have an
|
|
* oid. Seems worthwhile to display that.
|
|
*/
|
|
#define HeapTupleHeaderGetOidOld(tup) \
|
|
( \
|
|
((tup)->t_infomask & HEAP_HASOID_OLD) ? \
|
|
*((Oid *) ((char *)(tup) + (tup)->t_hoff - sizeof(Oid))) \
|
|
: \
|
|
InvalidOid \
|
|
)
|
|
|
|
|
|
/*
|
|
* bits_to_text
|
|
*
|
|
* Converts a bits8-array of 'len' bits to a human-readable
|
|
* c-string representation.
|
|
*/
|
|
static char *
|
|
bits_to_text(bits8 *bits, int len)
|
|
{
|
|
int i;
|
|
char *str;
|
|
|
|
str = palloc(len + 1);
|
|
|
|
for (i = 0; i < len; i++)
|
|
str[i] = (bits[(i / 8)] & (1 << (i % 8))) ? '1' : '0';
|
|
|
|
str[i] = '\0';
|
|
|
|
return str;
|
|
}
|
|
|
|
|
|
/*
|
|
* text_to_bits
|
|
*
|
|
* Converts a c-string representation of bits into a bits8-array. This is
|
|
* the reverse operation of previous routine.
|
|
*/
|
|
static bits8 *
|
|
text_to_bits(char *str, int len)
|
|
{
|
|
bits8 *bits;
|
|
int off = 0;
|
|
char byte = 0;
|
|
|
|
bits = palloc(len + 1);
|
|
|
|
while (off < len)
|
|
{
|
|
if (off % 8 == 0)
|
|
byte = 0;
|
|
|
|
if ((str[off] == '0') || (str[off] == '1'))
|
|
byte = byte | ((str[off] - '0') << off % 8);
|
|
else
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_DATA_CORRUPTED),
|
|
errmsg("illegal character '%c' in t_bits string", str[off])));
|
|
|
|
if (off % 8 == 7)
|
|
bits[off / 8] = byte;
|
|
|
|
off++;
|
|
}
|
|
|
|
return bits;
|
|
}
|
|
|
|
/*
|
|
* heap_page_items
|
|
*
|
|
* Allows inspection of line pointers and tuple headers of a heap page.
|
|
*/
|
|
PG_FUNCTION_INFO_V1(heap_page_items);
|
|
|
|
typedef struct heap_page_items_state
|
|
{
|
|
TupleDesc tupd;
|
|
Page page;
|
|
uint16 offset;
|
|
} heap_page_items_state;
|
|
|
|
Datum
|
|
heap_page_items(PG_FUNCTION_ARGS)
|
|
{
|
|
bytea *raw_page = PG_GETARG_BYTEA_P(0);
|
|
heap_page_items_state *inter_call_data = NULL;
|
|
FuncCallContext *fctx;
|
|
int raw_page_size;
|
|
|
|
if (!superuser())
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
|
|
(errmsg("must be superuser to use raw page functions"))));
|
|
|
|
raw_page_size = VARSIZE(raw_page) - VARHDRSZ;
|
|
|
|
if (SRF_IS_FIRSTCALL())
|
|
{
|
|
TupleDesc tupdesc;
|
|
MemoryContext mctx;
|
|
|
|
if (raw_page_size < SizeOfPageHeaderData)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
|
|
errmsg("input page too small (%d bytes)", raw_page_size)));
|
|
|
|
fctx = SRF_FIRSTCALL_INIT();
|
|
mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx);
|
|
|
|
inter_call_data = palloc(sizeof(heap_page_items_state));
|
|
|
|
/* Build a tuple descriptor for our result type */
|
|
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
|
|
elog(ERROR, "return type must be a row type");
|
|
|
|
inter_call_data->tupd = tupdesc;
|
|
|
|
inter_call_data->offset = FirstOffsetNumber;
|
|
inter_call_data->page = VARDATA(raw_page);
|
|
|
|
fctx->max_calls = PageGetMaxOffsetNumber(inter_call_data->page);
|
|
fctx->user_fctx = inter_call_data;
|
|
|
|
MemoryContextSwitchTo(mctx);
|
|
}
|
|
|
|
fctx = SRF_PERCALL_SETUP();
|
|
inter_call_data = fctx->user_fctx;
|
|
|
|
if (fctx->call_cntr < fctx->max_calls)
|
|
{
|
|
Page page = inter_call_data->page;
|
|
HeapTuple resultTuple;
|
|
Datum result;
|
|
ItemId id;
|
|
Datum values[14];
|
|
bool nulls[14];
|
|
uint16 lp_offset;
|
|
uint16 lp_flags;
|
|
uint16 lp_len;
|
|
|
|
memset(nulls, 0, sizeof(nulls));
|
|
|
|
/* Extract information from the line pointer */
|
|
|
|
id = PageGetItemId(page, inter_call_data->offset);
|
|
|
|
lp_offset = ItemIdGetOffset(id);
|
|
lp_flags = ItemIdGetFlags(id);
|
|
lp_len = ItemIdGetLength(id);
|
|
|
|
values[0] = UInt16GetDatum(inter_call_data->offset);
|
|
values[1] = UInt16GetDatum(lp_offset);
|
|
values[2] = UInt16GetDatum(lp_flags);
|
|
values[3] = UInt16GetDatum(lp_len);
|
|
|
|
/*
|
|
* We do just enough validity checking to make sure we don't reference
|
|
* data outside the page passed to us. The page could be corrupt in
|
|
* many other ways, but at least we won't crash.
|
|
*/
|
|
if (ItemIdHasStorage(id) &&
|
|
lp_len >= MinHeapTupleSize &&
|
|
lp_offset == MAXALIGN(lp_offset) &&
|
|
lp_offset + lp_len <= raw_page_size)
|
|
{
|
|
HeapTupleHeader tuphdr;
|
|
bytea *tuple_data_bytea;
|
|
int tuple_data_len;
|
|
|
|
/* Extract information from the tuple header */
|
|
|
|
tuphdr = (HeapTupleHeader) PageGetItem(page, id);
|
|
|
|
values[4] = UInt32GetDatum(HeapTupleHeaderGetRawXmin(tuphdr));
|
|
values[5] = UInt32GetDatum(HeapTupleHeaderGetRawXmax(tuphdr));
|
|
/* shared with xvac */
|
|
values[6] = UInt32GetDatum(HeapTupleHeaderGetRawCommandId(tuphdr));
|
|
values[7] = PointerGetDatum(&tuphdr->t_ctid);
|
|
values[8] = UInt32GetDatum(tuphdr->t_infomask2);
|
|
values[9] = UInt32GetDatum(tuphdr->t_infomask);
|
|
values[10] = UInt8GetDatum(tuphdr->t_hoff);
|
|
|
|
/* Copy raw tuple data into bytea attribute */
|
|
tuple_data_len = lp_len - tuphdr->t_hoff;
|
|
tuple_data_bytea = (bytea *) palloc(tuple_data_len + VARHDRSZ);
|
|
SET_VARSIZE(tuple_data_bytea, tuple_data_len + VARHDRSZ);
|
|
memcpy(VARDATA(tuple_data_bytea), (char *) tuphdr + tuphdr->t_hoff,
|
|
tuple_data_len);
|
|
values[13] = PointerGetDatum(tuple_data_bytea);
|
|
|
|
/*
|
|
* We already checked that the item is completely within the raw
|
|
* page passed to us, with the length given in the line pointer.
|
|
* Let's check that t_hoff doesn't point over lp_len, before using
|
|
* it to access t_bits and oid.
|
|
*/
|
|
if (tuphdr->t_hoff >= SizeofHeapTupleHeader &&
|
|
tuphdr->t_hoff <= lp_len &&
|
|
tuphdr->t_hoff == MAXALIGN(tuphdr->t_hoff))
|
|
{
|
|
if (tuphdr->t_infomask & HEAP_HASNULL)
|
|
{
|
|
int bits_len;
|
|
|
|
bits_len =
|
|
BITMAPLEN(HeapTupleHeaderGetNatts(tuphdr)) * BITS_PER_BYTE;
|
|
values[11] = CStringGetTextDatum(
|
|
bits_to_text(tuphdr->t_bits, bits_len));
|
|
}
|
|
else
|
|
nulls[11] = true;
|
|
|
|
if (tuphdr->t_infomask & HEAP_HASOID_OLD)
|
|
values[12] = HeapTupleHeaderGetOidOld(tuphdr);
|
|
else
|
|
nulls[12] = true;
|
|
}
|
|
else
|
|
{
|
|
nulls[11] = true;
|
|
nulls[12] = true;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/*
|
|
* The line pointer is not used, or it's invalid. Set the rest of
|
|
* the fields to NULL
|
|
*/
|
|
int i;
|
|
|
|
for (i = 4; i <= 13; i++)
|
|
nulls[i] = true;
|
|
}
|
|
|
|
/* Build and return the result tuple. */
|
|
resultTuple = heap_form_tuple(inter_call_data->tupd, values, nulls);
|
|
result = HeapTupleGetDatum(resultTuple);
|
|
|
|
inter_call_data->offset++;
|
|
|
|
SRF_RETURN_NEXT(fctx, result);
|
|
}
|
|
else
|
|
SRF_RETURN_DONE(fctx);
|
|
}
|
|
|
|
/*
|
|
* tuple_data_split_internal
|
|
*
|
|
* Split raw tuple data taken directly from a page into an array of bytea
|
|
* elements. This routine does a lookup on NULL values and creates array
|
|
* elements accordingly. This is a reimplementation of nocachegetattr()
|
|
* in heaptuple.c simplified for educational purposes.
|
|
*/
|
|
static Datum
|
|
tuple_data_split_internal(Oid relid, char *tupdata,
|
|
uint16 tupdata_len, uint16 t_infomask,
|
|
uint16 t_infomask2, bits8 *t_bits,
|
|
bool do_detoast)
|
|
{
|
|
ArrayBuildState *raw_attrs;
|
|
int nattrs;
|
|
int i;
|
|
int off = 0;
|
|
Relation rel;
|
|
TupleDesc tupdesc;
|
|
|
|
/* Get tuple descriptor from relation OID */
|
|
rel = relation_open(relid, AccessShareLock);
|
|
tupdesc = RelationGetDescr(rel);
|
|
|
|
raw_attrs = initArrayResult(BYTEAOID, CurrentMemoryContext, false);
|
|
nattrs = tupdesc->natts;
|
|
|
|
if (nattrs < (t_infomask2 & HEAP_NATTS_MASK))
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_DATA_CORRUPTED),
|
|
errmsg("number of attributes in tuple header is greater than number of attributes in tuple descriptor")));
|
|
|
|
for (i = 0; i < nattrs; i++)
|
|
{
|
|
Form_pg_attribute attr;
|
|
bool is_null;
|
|
bytea *attr_data = NULL;
|
|
|
|
attr = TupleDescAttr(tupdesc, i);
|
|
|
|
/*
|
|
* Tuple header can specify less attributes than tuple descriptor as
|
|
* ALTER TABLE ADD COLUMN without DEFAULT keyword does not actually
|
|
* change tuples in pages, so attributes with numbers greater than
|
|
* (t_infomask2 & HEAP_NATTS_MASK) should be treated as NULL.
|
|
*/
|
|
if (i >= (t_infomask2 & HEAP_NATTS_MASK))
|
|
is_null = true;
|
|
else
|
|
is_null = (t_infomask & HEAP_HASNULL) && att_isnull(i, t_bits);
|
|
|
|
if (!is_null)
|
|
{
|
|
int len;
|
|
|
|
if (attr->attlen == -1)
|
|
{
|
|
off = att_align_pointer(off, attr->attalign, -1,
|
|
tupdata + off);
|
|
|
|
/*
|
|
* As VARSIZE_ANY throws an exception if it can't properly
|
|
* detect the type of external storage in macros VARTAG_SIZE,
|
|
* this check is repeated to have a nicer error handling.
|
|
*/
|
|
if (VARATT_IS_EXTERNAL(tupdata + off) &&
|
|
!VARATT_IS_EXTERNAL_ONDISK(tupdata + off) &&
|
|
!VARATT_IS_EXTERNAL_INDIRECT(tupdata + off))
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_DATA_CORRUPTED),
|
|
errmsg("first byte of varlena attribute is incorrect for attribute %d", i)));
|
|
|
|
len = VARSIZE_ANY(tupdata + off);
|
|
}
|
|
else
|
|
{
|
|
off = att_align_nominal(off, attr->attalign);
|
|
len = attr->attlen;
|
|
}
|
|
|
|
if (tupdata_len < off + len)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_DATA_CORRUPTED),
|
|
errmsg("unexpected end of tuple data")));
|
|
|
|
if (attr->attlen == -1 && do_detoast)
|
|
attr_data = DatumGetByteaPCopy(tupdata + off);
|
|
else
|
|
{
|
|
attr_data = (bytea *) palloc(len + VARHDRSZ);
|
|
SET_VARSIZE(attr_data, len + VARHDRSZ);
|
|
memcpy(VARDATA(attr_data), tupdata + off, len);
|
|
}
|
|
|
|
off = att_addlength_pointer(off, attr->attlen,
|
|
tupdata + off);
|
|
}
|
|
|
|
raw_attrs = accumArrayResult(raw_attrs, PointerGetDatum(attr_data),
|
|
is_null, BYTEAOID, CurrentMemoryContext);
|
|
if (attr_data)
|
|
pfree(attr_data);
|
|
}
|
|
|
|
if (tupdata_len != off)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_DATA_CORRUPTED),
|
|
errmsg("end of tuple reached without looking at all its data")));
|
|
|
|
relation_close(rel, AccessShareLock);
|
|
|
|
return makeArrayResult(raw_attrs, CurrentMemoryContext);
|
|
}
|
|
|
|
/*
|
|
* tuple_data_split
|
|
*
|
|
* Split raw tuple data taken directly from page into distinct elements
|
|
* taking into account null values.
|
|
*/
|
|
PG_FUNCTION_INFO_V1(tuple_data_split);
|
|
|
|
Datum
|
|
tuple_data_split(PG_FUNCTION_ARGS)
|
|
{
|
|
Oid relid;
|
|
bytea *raw_data;
|
|
uint16 t_infomask;
|
|
uint16 t_infomask2;
|
|
char *t_bits_str;
|
|
bool do_detoast = false;
|
|
bits8 *t_bits = NULL;
|
|
Datum res;
|
|
|
|
relid = PG_GETARG_OID(0);
|
|
raw_data = PG_ARGISNULL(1) ? NULL : PG_GETARG_BYTEA_P(1);
|
|
t_infomask = PG_GETARG_INT16(2);
|
|
t_infomask2 = PG_GETARG_INT16(3);
|
|
t_bits_str = PG_ARGISNULL(4) ? NULL :
|
|
text_to_cstring(PG_GETARG_TEXT_PP(4));
|
|
|
|
if (PG_NARGS() >= 6)
|
|
do_detoast = PG_GETARG_BOOL(5);
|
|
|
|
if (!superuser())
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
|
|
errmsg("must be superuser to use raw page functions")));
|
|
|
|
if (!raw_data)
|
|
PG_RETURN_NULL();
|
|
|
|
/*
|
|
* Convert t_bits string back to the bits8 array as represented in the
|
|
* tuple header.
|
|
*/
|
|
if (t_infomask & HEAP_HASNULL)
|
|
{
|
|
int bits_str_len;
|
|
int bits_len;
|
|
|
|
bits_len = BITMAPLEN(t_infomask2 & HEAP_NATTS_MASK) * BITS_PER_BYTE;
|
|
if (!t_bits_str)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_DATA_CORRUPTED),
|
|
errmsg("argument of t_bits is null, but it is expected to be null and %d character long",
|
|
bits_len)));
|
|
|
|
bits_str_len = strlen(t_bits_str);
|
|
if (bits_len != bits_str_len)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_DATA_CORRUPTED),
|
|
errmsg("unexpected length of t_bits %u, expected %d",
|
|
bits_str_len, bits_len)));
|
|
|
|
/* do the conversion */
|
|
t_bits = text_to_bits(t_bits_str, bits_str_len);
|
|
}
|
|
else
|
|
{
|
|
if (t_bits_str)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_DATA_CORRUPTED),
|
|
errmsg("t_bits string is expected to be NULL, but instead it is %zu bytes length",
|
|
strlen(t_bits_str))));
|
|
}
|
|
|
|
/* Split tuple data */
|
|
res = tuple_data_split_internal(relid, (char *) raw_data + VARHDRSZ,
|
|
VARSIZE(raw_data) - VARHDRSZ,
|
|
t_infomask, t_infomask2, t_bits,
|
|
do_detoast);
|
|
|
|
if (t_bits)
|
|
pfree(t_bits);
|
|
|
|
PG_RETURN_ARRAYTYPE_P(res);
|
|
}
|