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Fix portability issues in pg_amcheck's 004_verify_heapam.pl.
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Test #12 overwrote a 1-byte varlena header to make it look like the
initial byte of a 4-byte varlena header, but the results were
endian-dependent. Also, the byte "abc" that followed the overwritten
byte would be interpreted differently depending on endian-ness.
Overwrite 4 bytes instead, in an endian-aware manner.

Test #13 accidentally managed to depend on TOAST_MAX_CHUNK_SIZE,
which varies slightly depending on MAXIMUM_ALIGNOF. That's not
the point anyway, so make the regexp insensitive to the expected
number of chunks.

Mark Dilger

Discussion: http://postgr.es/m/[email protected]
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@robertmhaas
robertmhaas committed Mar 12, 2021
1 parent 02b5940 commit 6611256
Showing 1 changed file with 42 additions and 30 deletions.
72 changes: 42 additions & 30 deletions src/bin/pg_amcheck/t/004_verify_heapam.pl
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Original file line number Diff line number Diff line change
Expand Up @@ -53,10 +53,10 @@
# We choose to read and write binary copies of our table's tuples, using perl's
# pack() and unpack() functions. Perl uses a packing code system in which:
#
# l = "signed 32-bit Long",
# L = "Unsigned 32-bit Long",
# S = "Unsigned 16-bit Short",
# C = "Unsigned 8-bit Octet",
# c = "signed 8-bit octet",
# q = "signed 64-bit quadword"
#
# Each tuple in our table has a layout as follows:
Expand All @@ -72,16 +72,16 @@
# xx t_hoff: x offset = 22 C
# xx t_bits: x offset = 23 C
# xx xx xx xx xx xx xx xx 'a': xxxxxxxx offset = 24 q
# xx xx xx xx xx xx xx xx 'b': xxxxxxxx offset = 32 Cccccccc
# xx xx xx xx xx xx xx xx 'c': xxxxxxxx offset = 40 SSSS
# xx xx xx xx xx xx xx xx : xxxxxxxx ...continued SSSS
# xx xx : xx ...continued S
# xx xx xx xx xx xx xx xx 'b': xxxxxxxx offset = 32 CCCCCCCC
# xx xx xx xx xx xx xx xx 'c': xxxxxxxx offset = 40 CCllLL
# xx xx xx xx xx xx xx xx : xxxxxxxx ...continued
# xx xx : xx ...continued
#
# We could choose to read and write columns 'b' and 'c' in other ways, but
# it is convenient enough to do it this way. We define packing code
# constants here, where they can be compared easily against the layout.

use constant HEAPTUPLE_PACK_CODE => 'LLLSSSSSCCqCcccccccSSSSSSSSS';
use constant HEAPTUPLE_PACK_CODE => 'LLLSSSSSCCqCCCCCCCCCCllLL';
use constant HEAPTUPLE_PACK_LENGTH => 58; # Total size

# Read a tuple of our table from a heap page.
Expand Down Expand Up @@ -121,15 +121,12 @@ sub read_tuple
b_body5 => shift,
b_body6 => shift,
b_body7 => shift,
c1 => shift,
c2 => shift,
c3 => shift,
c4 => shift,
c5 => shift,
c6 => shift,
c7 => shift,
c8 => shift,
c9 => shift);
c_va_header => shift,
c_va_vartag => shift,
c_va_rawsize => shift,
c_va_extsize => shift,
c_va_valueid => shift,
c_va_toastrelid => shift);
# Stitch together the text for column 'b'
$tup{b} = join('', map { chr($tup{"b_body$_"}) } (1..7));
return \%tup;
Expand Down Expand Up @@ -168,15 +165,12 @@ sub write_tuple
$tup->{b_body5},
$tup->{b_body6},
$tup->{b_body7},
$tup->{c1},
$tup->{c2},
$tup->{c3},
$tup->{c4},
$tup->{c5},
$tup->{c6},
$tup->{c7},
$tup->{c8},
$tup->{c9});
$tup->{c_va_header},
$tup->{c_va_vartag},
$tup->{c_va_rawsize},
$tup->{c_va_extsize},
$tup->{c_va_valueid},
$tup->{c_va_toastrelid});
seek($fh, $offset, 0)
or BAIL_OUT("seek failed: $!");
defined(syswrite($fh, $buffer, HEAPTUPLE_PACK_LENGTH))
Expand Down Expand Up @@ -273,6 +267,7 @@ sub write_tuple
or BAIL_OUT("open failed: $!");
binmode $file;

my $ENDIANNESS;
for (my $tupidx = 0; $tupidx < ROWCOUNT; $tupidx++)
{
my $offnum = $tupidx + 1; # offnum is 1-based, not zero-based
Expand All @@ -289,6 +284,9 @@ sub write_tuple
plan skip_all => qq(Page layout differs from our expectations: expected (12345678, "abcdefg"), got ($a, "$b"));
exit;
}

# Determine endianness of current platform from the 1-byte varlena header
$ENDIANNESS = $tup->{b_header} == 0x11 ? "little" : "big";
}
close($file)
or BAIL_OUT("close failed: $!");
Expand Down Expand Up @@ -459,22 +457,36 @@ sub header
}
elsif ($offnum == 12)
{
# Corrupt the bits in column 'b' 1-byte varlena header
$tup->{b_header} = 0x80;
# Overwrite column 'b' 1-byte varlena header and initial characters to
# look like a long 4-byte varlena
#
# On little endian machines, bytes ending in two zero bits (xxxxxx00 bytes)
# are 4-byte length word, aligned, uncompressed data (up to 1G). We set the
# high six bits to 111111 and the lower two bits to 00, then the next three
# bytes with 0xFF using 0xFCFFFFFF.
#
# On big endian machines, bytes starting in two zero bits (00xxxxxx bytes)
# are 4-byte length word, aligned, uncompressed data (up to 1G). We set the
# low six bits to 111111 and the high two bits to 00, then the next three
# bytes with 0xFF using 0x3FFFFFFF.
#
$tup->{b_header} = $ENDIANNESS eq 'little' ? 0xFC : 0x3F;
$tup->{b_body1} = 0xFF;
$tup->{b_body2} = 0xFF;
$tup->{b_body3} = 0xFF;

$header = header(0, $offnum, 1);
push @expected,
qr/${header}attribute 1 with length 4294967295 ends at offset 416848000 beyond total tuple length 58/;
qr/${header}attribute \d+ with length \d+ ends at offset \d+ beyond total tuple length \d+/;
}
elsif ($offnum == 13)
{
# Corrupt the bits in column 'c' toast pointer
$tup->{c6} = 41;
$tup->{c7} = 41;
$tup->{c_va_valueid} = 0xFFFFFFFF;

$header = header(0, $offnum, 2);
push @expected,
qr/${header}final toast chunk number 0 differs from expected value 6/,
qr/${header}final toast chunk number 0 differs from expected value \d+/,
qr/${header}toasted value for attribute 2 missing from toast table/;
}
elsif ($offnum == 14)
Expand Down

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