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Use whitelist to choose files scanned with pg_verify_checksums

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The original implementation of pg_verify_checksums used a blacklist to
decide which files should be skipped for scanning as they do not include
data checksums, like pg_internal.init or pg_control.  However, this
missed two things:
- Some files are created within builds of EXEC_BACKEND and these were
not listed, causing failures on Windows.
- Extensions may create custom files in data folders, causing the tool
to equally fail.

This commit switches to a whitelist-like method instead by checking if
the files to scan are authorized relation files.  This is close to a
reverse-engineering of what is defined in relpath.c in charge of
building the relation paths, and we could consider refactoring what this
patch does so as all routines are in a single place.  This is left for
later.

This is based on a suggestion from Andres Freund.  TAP tests are updated
so as multiple file patterns are tested.  The bug has been spotted by
various buildfarm members as a result of b34e84f which has introduced
the TAP tests of pg_verify_checksums.

Author: Michael Paquier
Reviewed-by: Andrew Dunstan, Michael Banck
Discussion: https://postgr.es/m/20181012005614.GC26424@paquier.xyz
Backpatch-through: 11
This commit is contained in:
Michael Paquier 2018-10-19 22:44:12 +09:00
parent 06292bb949
commit cc7f27eae8
1 changed files with 60 additions and 17 deletions
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77
src/bin/pg_verify_checksums/pg_verify_checksums.c
View File

@ -15,6 +15,7 @@
#include "catalog/pg_control.h"
#include "common/controldata_utils.h"
#include "common/relpath.h"
#include "getopt_long.h"
#include "pg_getopt.h"
#include "storage/bufpage.h"
@ -49,27 +50,69 @@ usage(void)
printf(_("Report bugs to <pgsql-bugs@postgresql.org>.\n"));
}
static const char *const skip[] = {
"pg_control",
"pg_filenode.map",
"pg_internal.init",
"PG_VERSION",
NULL,
};
/*
* isRelFileName
*
* Check if the given file name is authorized for checksum verification.
*/
static bool
skipfile(const char *fn)
isRelFileName(const char *fn)
{
const char *const *f;
int pos;
if (strcmp(fn, ".") == 0 ||
strcmp(fn, "..") == 0)
/*----------
* Only files including data checksums are authorized for verification.
* This is guessed based on the file name by reverse-engineering
* GetRelationPath() so make sure to update both code paths if any
* updates are done. The following file name formats are allowed:
* <digits>
* <digits>.<segment>
* <digits>_<forkname>
* <digits>_<forkname>.<segment>
*
* Note that temporary files, beginning with 't', are also skipped.
*
*----------
*/
/* A non-empty string of digits should follow */
for (pos = 0; isdigit((unsigned char) fn[pos]); ++pos)
;
/* leave if no digits */
if (pos == 0)
return false;
/* good to go if only digits */
if (fn[pos] == '\0')
return true;
for (f = skip; *f; f++)
if (strcmp(*f, fn) == 0)
return true;
return false;
/* Authorized fork files can be scanned */
if (fn[pos] == '_')
{
int forkchar = forkname_chars(&fn[pos + 1], NULL);
if (forkchar <= 0)
return false;
pos += forkchar + 1;
}
/* Check for an optional segment number */
if (fn[pos] == '.')
{
int segchar;
for (segchar = 1; isdigit((unsigned char) fn[pos + segchar]); ++segchar)
;
if (segchar <= 1)
return false;
pos += segchar;
}
/* Now this should be the end */
if (fn[pos] != '\0')
return false;
return true;
}
static void
@ -146,7 +189,7 @@ scan_directory(const char *basedir, const char *subdir)
char fn[MAXPGPATH];
struct stat st;
if (skipfile(de->d_name))
if (!isRelFileName(de->d_name))
continue;
snprintf(fn, sizeof(fn), "%s/%s", path, de->d_name);