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Fix tar files emitted by pg_basebackup to be POSIX conformant.

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Back-patch portions of commit 05b555d12b.
There doesn't seem to be any reason not to fix pg_basebackup fully, but
we can't change pg_dump's "magic" string without breaking older versions
of pg_restore.  Instead, just patch pg_restore to accept either version
of the magic string, in hopes of avoiding compatibility problems when
9.3 comes out.  I also fixed pg_dump to write the correct 2-block EOF
marker, since that won't create a compatibility problem with pg_restore
and it could help with some versions of tar.

Brian Weaver and Tom Lane
This commit is contained in:
Tom Lane
2012-09-28 15:35:46 -04:00
parent f2366e584a
commit 900d77fa57
3 changed files with 64 additions and 34 deletions
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27
src/bin/pg_dump/pg_backup_tar.c
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@@ -882,8 +882,10 @@ _CloseArchive(ArchiveHandle *AH)
tarClose(AH, th);
/* Add a block of NULLs since it's de-rigeur. */
for (i = 0; i < 512; i++)
/*
* EOF marker for tar files is two blocks of NULLs.
*/
for (i = 0; i < 512 * 2; i++)
{
if (fputc(0, ctx->tarFH) == EOF)
exit_horribly(modulename,
@@ -1032,11 +1034,16 @@ _tarChecksum(char *header)
int i,
sum;
sum = 0;
/*
* Per POSIX, the checksum is the simple sum of all bytes in the header,
* treating the bytes as unsigned, and treating the checksum field (at
* offset 148) as though it contained 8 spaces.
*/
sum = 8 * ' '; /* presumed value for checksum field */
for (i = 0; i < 512; i++)
if (i < 148 || i >= 156)
sum += 0xFF & header[i];
return sum + 256; /* Assume 8 blanks in checksum field */
return sum;
}
bool
@@ -1050,11 +1057,15 @@ isValidTarHeader(char *header)
if (sum != chk)
return false;
/* POSIX format */
if (strncmp(&header[257], "ustar00", 7) == 0)
/* POSIX tar format */
if (memcmp(&header[257], "ustar\0", 6) == 0 &&
memcmp(&header[263], "00", 2) == 0)
return true;
/* older format */
if (strncmp(&header[257], "ustar ", 7) == 0)
/* GNU tar format */
if (memcmp(&header[257], "ustar \0", 8) == 0)
return true;
/* not-quite-POSIX format written by pre-9.3 pg_dump */
if (memcmp(&header[257], "ustar00\0", 8) == 0)
return true;
return false;