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".

3 files changed, 40 insertions, 9 deletions

diff --git a/src/backend/parser/scansup.c b/src/backend/parser/scansup.c
index efa851ea0ba..061b68b359f 100644
--- a/src/backend/parser/scansup.c
+++ b/src/backend/parser/scansup.c
@@ -9,7 +9,7 @@
  *
  *
  * 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);
 		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,
 					(errcode(ERRCODE_NAME_TOO_LONG),
-					 errmsg("identifier \"%s\" will be truncated to \"%.*s\"",
-							ident, len, ident)));
+					 errmsg("identifier \"%s\" will be truncated to \"%s\"",
+							ident, buf)));
+		}
 		ident[len] = '\0';
 	}
 }
diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
index 77ca1cec33d..73170457675 100644
--- a/src/backend/utils/error/elog.c
+++ b/src/backend/utils/error/elog.c
@@ -42,7 +42,7 @@
  *
  *
  * 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;
 
 					psdisp = get_ps_display(&displen);
-					appendStringInfo(buf, "%.*s", displen, psdisp);
+					appendBinaryStringInfo(buf, psdisp, displen);
 				}
 				break;
 			case 'r':
diff --git a/src/interfaces/libpq/fe-misc.c b/src/interfaces/libpq/fe-misc.c
index cd9f56fe38b..fff8b6e3881 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 1.122.2.1 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 $
  *
  *-------------------------------------------------------------------------
  */
@@ -70,6 +70,20 @@ 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
  *
  *	All these routines return 0 on success, EOF on error.
@@ -175,8 +189,11 @@ 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;
 }
@@ -192,7 +209,11 @@ 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;
 }