From 27594103806c8e209993f31a50d91d7add968b2f Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sat, 8 May 2010 16:40:31 +0000 Subject: Work around a subtle portability problem in use of printf %s format. 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". --- src/interfaces/libpq/fe-misc.c | 29 +++++++++++++++++++++++++---- 1 file changed, 25 insertions(+), 4 deletions(-) (limited to 'src/interfaces/libpq/fe-misc.c') diff --git a/src/interfaces/libpq/fe-misc.c b/src/interfaces/libpq/fe-misc.c index 17b9ed3e856..108995b0041 100644 --- a/src/interfaces/libpq/fe-misc.c +++ b/src/interfaces/libpq/fe-misc.c @@ -23,7 +23,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/interfaces/libpq/fe-misc.c,v 1.130.2.1 2008/08/20 11:53:49 mha Exp $ + * $PostgreSQL: pgsql/src/interfaces/libpq/fe-misc.c,v 1.130.2.2 2010/05/08 16:40:31 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -67,6 +67,20 @@ static int pqSocketCheck(PGconn *conn, int forRead, int forWrite, 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 * @@ -173,8 +187,11 @@ pqGetnchar(char *s, size_t len, PGconn *conn) conn->inCursor += len; 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; } @@ -190,7 +207,11 @@ pqPutnchar(const char *s, size_t len, PGconn *conn) return EOF; 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; } -- cgit v1.2.3