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Work around a subtle portability problem in use of printf %s format.

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Depending on which spec you read, field widths and precisions in %s may be
counted either in bytes or characters.  Our code was assuming bytes, which
is wrong at least for glibc's implementation, and in any case libc might
have a different idea of the prevailing encoding than we do.  Hence, for
portable results we must avoid using anything more complex than just "%s"
unless the string to be printed is known to be all-ASCII.

This patch fixes the cases I could find, including the psql formatting
failure reported by Hernan Gonzalez.  In HEAD only, I also added comments
to some places where it appears safe to continue using "%.*s".
This commit is contained in:
Tom Lane
2010-05-08 16:39:53 +00:00
parent 71a185a24d
commit 54cd4f0457
11 changed files with 111 additions and 31 deletions
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11
src/backend/utils/adt/datetime.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/datetime.c,v 1.210 2010/01/02 16:57:53 momjian Exp $
* $PostgreSQL: pgsql/src/backend/utils/adt/datetime.c,v 1.211 2010/05/08 16:39:51 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -3740,6 +3740,14 @@ EncodeDateTime(struct pg_tm * tm, fsec_t fsec, int *tzp, char **tzn, int style,
AppendTimestampSeconds(str + strlen(str), tm, fsec);
/*
* Note: the uses of %.*s in this function would be unportable
* if the timezone names ever contain non-ASCII characters,
* since some platforms think the string length is measured
* in characters not bytes. However, all TZ abbreviations in
* the Olson database are plain ASCII.
*/
if (tzp != NULL && tm->tm_isdst >= 0)
{
if (*tzn != NULL)
@ -4091,6 +4099,7 @@ CheckDateTokenTable(const char *tablename, const datetkn *base, int nel)
{
if (strncmp(base[i - 1].token, base[i].token, TOKMAXLEN) >= 0)
{
/* %.*s is safe since all our tokens are ASCII */
elog(LOG, "ordering error in %s table: \"%.*s\" >= \"%.*s\"",
tablename,
TOKMAXLEN, base[i - 1].token,