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".

diff --git a/src/backend/parser/scansup.c b/src/backend/parser/scansup.c
index b4d8612d6c95722824945cb062d91968b280fc63..7aa406ff7c0b342b08f1393d923d1408aa6c1e31 100644 (file)
--- 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 1.37 2009/01/01 17:23:46 momjian Exp $
+ *   $PostgreSQL: pgsql/src/backend/parser/scansup.c,v 1.37.2.1 2010/05/08 16:40:03 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -176,10 +176,20 @@ 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 db334824347b781c5cb764d43e9220e29bca4fdb..7b9a62b00c97d7744a504afb135e433a88261e2c 100644 (file)
--- 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 1.216 2009/06/25 23:07:15 tgl Exp $
+ *   $PostgreSQL: pgsql/src/backend/utils/error/elog.c,v 1.216.2.1 2010/05/08 16:40:03 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1782,7 +1782,7 @@ log_line_prefix(StringInfo buf)
                    int         displen;
 
                    psdisp = get_ps_display(&displen);
-                   appendStringInfo(buf, "%.*s", displen, psdisp);
+                   appendBinaryStringInfo(buf, psdisp, displen);
                }
                break;
            case 'r':
@@ -1937,7 +1937,7 @@ write_csvlog(ErrorData *edata)
        initStringInfo(&msgbuf);
 
        psdisp = get_ps_display(&displen);
-       appendStringInfo(&msgbuf, "%.*s", displen, psdisp);
+       appendBinaryStringInfo(&msgbuf, psdisp, displen);
        appendCSVLiteral(&buf, msgbuf.data);
 
        pfree(msgbuf.data);

diff --git a/src/bin/psql/print.c b/src/bin/psql/print.c
index 4a091ab45f81225eea6321007cadc56a91d314b9..5c0547c260514d8973a515887bd2a6c53e4f9dd7 100644 (file)
--- a/src/bin/psql/print.c
+++ b/src/bin/psql/print.c
@@ -3,7 +3,7 @@
  *
  * Copyright (c) 2000-2009, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/bin/psql/print.c,v 1.116.2.3 2010/03/01 21:27:32 heikki Exp $
+ * $PostgreSQL: pgsql/src/bin/psql/print.c,v 1.116.2.4 2010/05/08 16:40:03 tgl Exp $
  */
 #include "postgres_fe.h"
 
@@ -172,6 +172,20 @@ format_numeric_locale(const char *my_str)
    return new_str;
 }
 
+/*
+ * 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);
+}
+
+
 /*************************/
 /* Unaligned text       */
 /*************************/
@@ -813,14 +827,16 @@ print_aligned_text(const printTableContent *cont, FILE *fout)
                    {
                        /* spaces first */
                        fprintf(fout, "%*s", width_wrap[j] - chars_to_output, "");
-                       fprintf(fout, "%.*s", bytes_to_output,
-                               this_line->ptr + bytes_output[j]);
+                       fputnbytes(fout,
+                                  this_line->ptr + bytes_output[j],
+                                  bytes_to_output);
                    }
                    else    /* Left aligned cell */
                    {
                        /* spaces second */
-                       fprintf(fout, "%.*s", bytes_to_output,
-                               this_line->ptr + bytes_output[j]);
+                       fputnbytes(fout,
+                                  this_line->ptr + bytes_output[j],
+                                  bytes_to_output);
                        if (finalspaces)
                            fprintf(fout, "%*s", width_wrap[j] - chars_to_output, "");
                    }
@@ -1030,7 +1046,10 @@ print_aligned_vertical(const printTableContent *cont, FILE *fout)
                record_str_len = strlen(record_str);
 
                if (record_str_len + opt_border > strlen(divider))
+               {
+                   /* %.*s OK here because divider is all ASCII */
                    fprintf(fout, "%.*s%s\n", opt_border, divider, record_str);
+               }
                else
                {
                    char       *div_copy = pg_strdup(divider);

diff --git a/src/interfaces/libpq/fe-misc.c b/src/interfaces/libpq/fe-misc.c
index 4ae6cdc9109e6427280af98ee3fc533c9a7e2e61..561d95736e5a553a8ab69c5f261a21a000a56e03 100644 (file)
--- 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 1.140 2009/06/11 14:49:14 momjian Exp $
+ *   $PostgreSQL: pgsql/src/interfaces/libpq/fe-misc.c,v 1.140.2.1 2010/05/08 16:40:03 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
  *
@@ -187,8 +201,11 @@ 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;
 }
@@ -204,7 +221,11 @@ 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;
 }