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Correct some code in pg_restore when reading the header of a tar archive:

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(1) The code doesn't initialize `sum', so the initial "does the checksum
    match?" test is wrong.

(2) The loop that is intended to check for a "null block" just checks
    the first byte of the tar block 512 times, rather than each of the
    512 bytes one time (!), which I'm guessing was the intent.

It was only through sheer luck that this worked in the first place.

Per Coverity static analysis performed by EnterpriseDB.
This commit is contained in:
Neil Conway
2005-06-22 02:12:19 +00:00
parent a6f0dee775
commit 0592a1ebc1
1 changed files with 9 additions and 9 deletions
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18
src/bin/pg_dump/pg_backup_tar.c
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@@ -16,7 +16,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/bin/pg_dump/pg_backup_tar.c,v 1.38 2003/10/08 03:52:32 momjian Exp $
* $Header: /cvsroot/pgsql/src/bin/pg_dump/pg_backup_tar.c,v 1.38.2.1 2005/06/22 02:12:19 neilc Exp $
*
*-------------------------------------------------------------------------
*/
@@ -1153,7 +1153,6 @@ _tarGetHeader(ArchiveHandle *AH, TAR_MEMBER *th)
size_t len;
unsigned long ullen;
off_t hPos;
int i;
bool gotBlock = false;
while (!gotBlock)
@@ -1176,7 +1175,7 @@ _tarGetHeader(ArchiveHandle *AH, TAR_MEMBER *th)
hPos = ctx->tarFHpos;
/* Read a 512 byte block, return EOF, exit if short */
len = _tarReadRaw(AH, &h[0], 512, NULL, ctx->tarFH);
len = _tarReadRaw(AH, h, 512, NULL, ctx->tarFH);
if (len == 0) /* EOF */
return 0;
@@ -1186,20 +1185,22 @@ _tarGetHeader(ArchiveHandle *AH, TAR_MEMBER *th)
(unsigned long) len);
/* Calc checksum */
chk = _tarChecksum(&h[0]);
chk = _tarChecksum(h);
sscanf(&h[148], "%8o", &sum);
/*
* If the checksum failed, see if it is a null block. If so, then
* just try with next block...
* If the checksum failed, see if it is a null block. If so,
* silently continue to the next block.
*/
if (chk == sum)
gotBlock = true;
else
{
int i;
for (i = 0; i < 512; i++)
{
if (h[0] != 0)
if (h[i] != 0)
{
gotBlock = true;
break;
@@ -1211,7 +1212,6 @@ _tarGetHeader(ArchiveHandle *AH, TAR_MEMBER *th)
sscanf(&h[0], "%99s", tag);
sscanf(&h[124], "%12lo", &ullen);
len = (size_t) ullen;
sscanf(&h[148], "%8o", &sum);
{
char buf[100];