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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 16:40:38 +00:00
parent ddcba86256
commit 7e84802ce5
3 changed files with 40 additions and 9 deletions
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16
src/backend/parser/scansup.c
View File

@ -9,7 +9,7 @@
* *
* *
* IDENTIFICATION * IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/parser/scansup.c,v 1.30 2005/10/15 02:49:22 momjian Exp $ * $PostgreSQL: pgsql/src/backend/parser/scansup.c,v 1.30.2.1 2010/05/08 16:40:38 tgl Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -177,10 +177,20 @@ truncate_identifier(char *ident, int len, bool warn)
{ {
len = pg_mbcliplen(ident, len, NAMEDATALEN - 1); len = pg_mbcliplen(ident, len, NAMEDATALEN - 1);
if (warn) if (warn)
{
/*
* Cannot use %.*s here because some machines interpret %s's
* precision in characters, others in bytes.
*/
char buf[NAMEDATALEN];
memcpy(buf, ident, len);
buf[len] = '\0';
ereport(NOTICE, ereport(NOTICE,
(errcode(ERRCODE_NAME_TOO_LONG), (errcode(ERRCODE_NAME_TOO_LONG),
errmsg("identifier \"%s\" will be truncated to \"%.*s\"", errmsg("identifier \"%s\" will be truncated to \"%s\"",
ident, len, ident))); ident, buf)));
}
ident[len] = '\0'; ident[len] = '\0';
} }
} }

4
src/backend/utils/error/elog.c
View File

@ -42,7 +42,7 @@
* *
* *
* IDENTIFICATION * IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/error/elog.c,v 1.167.2.9 2009/03/03 00:17:29 tgl Exp $ * $PostgreSQL: pgsql/src/backend/utils/error/elog.c,v 1.167.2.10 2010/05/08 16:40:38 tgl Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -1547,7 +1547,7 @@ log_line_prefix(StringInfo buf)
int displen; int displen;
psdisp = get_ps_display(&displen); psdisp = get_ps_display(&displen);
appendStringInfo(buf, "%.*s", displen, psdisp); appendBinaryStringInfo(buf, psdisp, displen);
} }
break; break;
case 'r': case 'r':

29
src/interfaces/libpq/fe-misc.c
View File

@ -23,7 +23,7 @@
* Portions Copyright (c) 1994, Regents of the University of California * Portions Copyright (c) 1994, Regents of the University of California
* *
* IDENTIFICATION * IDENTIFICATION
* $PostgreSQL: pgsql/src/interfaces/libpq/fe-misc.c,v 1.122.2.1 2005/11/22 18:23:30 momjian Exp $ * $PostgreSQL: pgsql/src/interfaces/libpq/fe-misc.c,v 1.122.2.2 2010/05/08 16:40:38 tgl Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -69,6 +69,20 @@ static int pqSocketCheck(PGconn *conn, int forRead, int forWrite,
static int pqSocketPoll(int sock, int forRead, int forWrite, time_t end_time); static int pqSocketPoll(int sock, int forRead, int forWrite, time_t end_time);
/*
* fputnbytes: print exactly N bytes to a file
*
* Think not to use fprintf with a %.*s format for this. Some machines
* believe %s's precision is measured in characters, others in bytes.
*/
static void
fputnbytes(FILE *f, const char *str, size_t n)
{
while (n-- > 0)
fputc(*str++, f);
}
/* /*
* pqGetc: get 1 character from the connection * pqGetc: get 1 character from the connection
* *
@ -175,8 +189,11 @@ pqGetnchar(char *s, size_t len, PGconn *conn)
conn->inCursor += len; conn->inCursor += len;
if (conn->Pfdebug) if (conn->Pfdebug)
fprintf(conn->Pfdebug, "From backend (%lu)> %.*s\n", {
(unsigned long) len, (int) len, s); fprintf(conn->Pfdebug, "From backend (%lu)> ", (unsigned long) len);
fputnbytes(conn->Pfdebug, s, len);
fprintf(conn->Pfdebug, "\n");
}
return 0; return 0;
} }
@ -192,7 +209,11 @@ pqPutnchar(const char *s, size_t len, PGconn *conn)
return EOF; return EOF;
if (conn->Pfdebug) if (conn->Pfdebug)
fprintf(conn->Pfdebug, "To backend> %.*s\n", (int) len, s); {
fprintf(conn->Pfdebug, "To backend> ");
fputnbytes(conn->Pfdebug, s, len);
fprintf(conn->Pfdebug, "\n");
}
return 0; return 0;
} }