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Prevent integer overflows during units conversion when displaying a GUC

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variable that has units.  Per report from Stefan Kaltenbrunner.

Backport to 8.2.  I also backported my patch of 2007-06-21 that prevented
comparable overflows on the input side, since that now seems to have enough
field track record to be back-patched safely.  That patch included addition
of hints listing the available unit names, which I did not bother to strip
out of it --- this will make a little more work for the translators, but
they can copy the translation from 8.3, and anyway an untranslated hint
is better than no hint.
This commit is contained in:
Tom Lane
2008-07-06 19:48:53 +00:00
parent bbfb4a0ab9
commit e3780bce58
1 changed files with 25 additions and 16 deletions
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41
src/backend/utils/misc/guc.c
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@@ -10,7 +10,7 @@
* Written by Peter Eisentraut <peter_e@gmx.net>. * Written by Peter Eisentraut <peter_e@gmx.net>.
* *
* IDENTIFICATION * IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.432.2.1 2008/05/26 18:54:36 tgl Exp $ * $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.432.2.2 2008/07/06 19:48:53 tgl Exp $
* *
*-------------------------------------------------------------------- *--------------------------------------------------------------------
*/ */
@@ -5824,10 +5824,18 @@ _ShowOption(struct config_generic * record, bool use_units)
val = (*conf->show_hook) (); val = (*conf->show_hook) ();
else else
{ {
char unit[4]; /*
int result = *conf->variable; * Use int64 arithmetic to avoid overflows in units
* conversion. If INT64_IS_BUSTED we might overflow
* anyway and print bogus answers, but there are few
* enough such machines that it doesn't seem worth
* trying harder.
*/
int64 result = *conf->variable;
const char *unit;
if (use_units && result > 0 && (record->flags & GUC_UNIT_MEMORY)) if (use_units && result > 0 &&
(record->flags & GUC_UNIT_MEMORY))
{ {
switch (record->flags & GUC_UNIT_MEMORY) switch (record->flags & GUC_UNIT_MEMORY)
{ {
@@ -5842,19 +5850,20 @@ _ShowOption(struct config_generic * record, bool use_units)
if (result % KB_PER_GB == 0) if (result % KB_PER_GB == 0)
{ {
result /= KB_PER_GB; result /= KB_PER_GB;
strcpy(unit, "GB"); unit = "GB";
} }
else if (result % KB_PER_MB == 0) else if (result % KB_PER_MB == 0)
{ {
result /= KB_PER_MB; result /= KB_PER_MB;
strcpy(unit, "MB"); unit = "MB";
} }
else else
{ {
strcpy(unit, "kB"); unit = "kB";
} }
} }
else if (use_units && result > 0 && (record->flags & GUC_UNIT_TIME)) else if (use_units && result > 0 &&
(record->flags & GUC_UNIT_TIME))
{ {
switch (record->flags & GUC_UNIT_TIME) switch (record->flags & GUC_UNIT_TIME)
{ {
@@ -5869,33 +5878,33 @@ _ShowOption(struct config_generic * record, bool use_units)
if (result % MS_PER_D == 0) if (result % MS_PER_D == 0)
{ {
result /= MS_PER_D; result /= MS_PER_D;
strcpy(unit, "d"); unit = "d";
} }
else if (result % MS_PER_H == 0) else if (result % MS_PER_H == 0)
{ {
result /= MS_PER_H; result /= MS_PER_H;
strcpy(unit, "h"); unit = "h";
} }
else if (result % MS_PER_MIN == 0) else if (result % MS_PER_MIN == 0)
{ {
result /= MS_PER_MIN; result /= MS_PER_MIN;
strcpy(unit, "min"); unit = "min";
} }
else if (result % MS_PER_S == 0) else if (result % MS_PER_S == 0)
{ {
result /= MS_PER_S; result /= MS_PER_S;
strcpy(unit, "s"); unit = "s";
} }
else else
{ {
strcpy(unit, "ms"); unit = "ms";
} }
} }
else else
strcpy(unit, ""); unit = "";
snprintf(buffer, sizeof(buffer), "%d%s", snprintf(buffer, sizeof(buffer), INT64_FORMAT "%s",
(int) result, unit); result, unit);
val = buffer; val = buffer;
} }
} }