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".

1 files changed, 9 insertions, 9 deletions

diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index a591dec792a..98f13750bf2 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -3,7 +3,7 @@
  *
  * Copyright (c) 2000-2010, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/bin/psql/help.c,v 1.157 2010/03/07 17:02:34 mha Exp $
+ * $PostgreSQL: pgsql/src/bin/psql/help.c,v 1.158 2010/05/08 16:39:51 tgl Exp $
  */
 #include "postgres_fe.h"
 
@@ -284,6 +284,7 @@ slashUsage(unsigned short int pager)
 /*
  * helpSQL -- help with SQL commands
  *
+ * Note: we assume caller removed any trailing spaces in "topic".
  */
 void
 helpSQL(const char *topic, unsigned short int pager)
@@ -352,17 +353,16 @@ helpSQL(const char *topic, unsigned short int pager)
 					wordlen;
 		int			nl_count = 0;
 
-		/* User gets two chances: exact match, then the first word */
-
-		/* First pass : strip trailing spaces and semicolons */
+		/*
+		 * We first try exact match, then first + second words, then first
+		 * word only.
+		 */
 		len = strlen(topic);
-		while (topic[len - 1] == ' ' || topic[len - 1] == ';')
-			len--;
 
-		for (x = 1; x <= 3; x++)	/* Three chances to guess that word... */
+		for (x = 1; x <= 3; x++)
 		{
 			if (x > 1)			/* Nothing on first pass - try the opening
-								 * words */
+								 * word(s) */
 			{
 				wordlen = j = 1;
 				while (topic[j] != ' ' && j++ < len)
@@ -423,7 +423,7 @@ helpSQL(const char *topic, unsigned short int pager)
 		}
 
 		if (!help_found)
-			fprintf(output, _("No help available for \"%-.*s\".\nTry \\h with no arguments to see available help.\n"), (int) len, topic);
+			fprintf(output, _("No help available for \"%s\".\nTry \\h with no arguments to see available help.\n"), topic);
 
 		/* Only close if we used the pager */
 		if (output != stdout)