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/lib/stringinfo.c b/src/backend/lib/stringinfo.c
index 88db51871e914bcce9c4e435850b94bf5541f7ec..9ae2455000f7706ecdc6c19cf27bd978e6ffc83c 100644 (file)
--- a/src/backend/lib/stringinfo.c
+++ b/src/backend/lib/stringinfo.c
@@ -9,7 +9,7 @@
  * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *       $PostgreSQL: pgsql/src/backend/lib/stringinfo.c,v 1.52 2010/01/02 16:57:45 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/lib/stringinfo.c,v 1.53 2010/05/08 16:39:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -226,7 +226,8 @@ appendBinaryStringInfo(StringInfo str, const char *data, int datalen)
 
        /*
         * Keep a trailing null in place, even though it's probably useless for
-        * binary data...
+        * binary data.  (Some callers are dealing with text but call this
+        * because their input isn't null-terminated.)
         */
        str->data[str->len] = '\0';
 }

diff --git a/src/backend/parser/scansup.c b/src/backend/parser/scansup.c
index 5bc6d8d6071081f47deb57000e2f6c6b909ed1f9..417c79dd14ea29e02236f1f221ad4f92709e300e 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 1.39 2010/01/02 16:57:50 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/parser/scansup.c,v 1.40 2010/05/08 16:39:49 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/tsearch/wparser_def.c b/src/backend/tsearch/wparser_def.c
index a2da9210c4c7128cb4390dd11a628f63dc5947d6..d2e47ceaf5e32dd53f53014055ffb26b67d45dab 100644 (file)
--- a/src/backend/tsearch/wparser_def.c
+++ b/src/backend/tsearch/wparser_def.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/tsearch/wparser_def.c,v 1.30 2010/04/28 02:04:16 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/tsearch/wparser_def.c,v 1.31 2010/05/08 16:39:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -322,6 +322,12 @@ TParserInit(char *str, int len)
        prs->state->state = TPS_Base;
 
 #ifdef WPARSER_TRACE
+       /*
+        * Use of %.*s here is not portable when the string contains multibyte
+        * characters: some machines interpret the length in characters, others
+        * in bytes.  Since it's only a debugging aid, we haven't bothered to
+        * fix this.
+        */
        fprintf(stderr, "parsing \"%.*s\"\n", len, str);
 #endif
 
@@ -361,6 +367,7 @@ TParserCopyInit(const TParser *orig)
        prs->state->state = TPS_Base;
 
 #ifdef WPARSER_TRACE
+       /* See note above about %.*s */
        fprintf(stderr, "parsing copy of \"%.*s\"\n", prs->lenstr, prs->str);
 #endif
 

diff --git a/src/backend/utils/adt/datetime.c b/src/backend/utils/adt/datetime.c
index f9e40f115fc98b466ef42e4fa0f4feb422a5618e..743ca8345d609d96a09bd49cbe674773988dbee9 100644 (file)
--- a/src/backend/utils/adt/datetime.c
+++ b/src/backend/utils/adt/datetime.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/utils/adt/datetime.c,v 1.210 2010/01/02 16:57:53 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/utils/adt/datetime.c,v 1.211 2010/05/08 16:39:51 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -3740,6 +3740,14 @@ EncodeDateTime(struct pg_tm * tm, fsec_t fsec, int *tzp, char **tzn, int style,
 
                        AppendTimestampSeconds(str + strlen(str), tm, fsec);
 
+                       /*
+                        * Note: the uses of %.*s in this function would be unportable
+                        * if the timezone names ever contain non-ASCII characters,
+                        * since some platforms think the string length is measured
+                        * in characters not bytes.  However, all TZ abbreviations in
+                        * the Olson database are plain ASCII.
+                        */
+
                        if (tzp != NULL && tm->tm_isdst >= 0)
                        {
                                if (*tzn != NULL)
@@ -4091,6 +4099,7 @@ CheckDateTokenTable(const char *tablename, const datetkn *base, int nel)
        {
                if (strncmp(base[i - 1].token, base[i].token, TOKMAXLEN) >= 0)
                {
+                       /* %.*s is safe since all our tokens are ASCII */
                        elog(LOG, "ordering error in %s table: \"%.*s\" >= \"%.*s\"",
                                 tablename,
                                 TOKMAXLEN, base[i - 1].token,

diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
index a6992e65d94544899be6bb201dced1bf73b9d37c..b2fab359b8744f3e82bb253681b67739598160e5 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 1.223 2010/02/26 02:01:12 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/utils/error/elog.c,v 1.224 2010/05/08 16:39:51 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1871,7 +1871,7 @@ log_line_prefix(StringInfo buf, ErrorData *edata)
                                        int                     displen;
 
                                        psdisp = get_ps_display(&displen);
-                                       appendStringInfo(buf, "%.*s", displen, psdisp);
+                                       appendBinaryStringInfo(buf, psdisp, displen);
                                }
                                break;
                        case 'r':
@@ -2029,7 +2029,7 @@ 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/command.c b/src/bin/psql/command.c
index 4a94a1ace12ae731d6a65246ae337f8ff6579f40..b9624451c3530806fd3ab5da8bbc97add5e824bd 100644 (file)
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -3,7 +3,7 @@
  *
  * Copyright (c) 2000-2010, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/bin/psql/command.c,v 1.218 2010/04/03 20:55:57 tgl Exp $
+ * $PostgreSQL: pgsql/src/bin/psql/command.c,v 1.219 2010/05/08 16:39:51 tgl Exp $
  */
 #include "postgres_fe.h"
 #include "command.h"
@@ -651,6 +651,13 @@ exec_command(const char *cmd,
        {
                char       *opt = psql_scan_slash_option(scan_state,
                                                                                                 OT_WHOLE_LINE, NULL, false);
+               size_t          len;
+
+               /* strip any trailing spaces and semicolons */
+               len = strlen(opt);
+               while (len > 0 &&
+                          (isspace((unsigned char) opt[len - 1]) || opt[len - 1] == ';'))
+                       opt[--len] = '\0';
 
                helpSQL(opt, pset.popt.topt.pager);
                free(opt);

diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index a591dec792ae48c38d44c1b1ba65e9e3bc90b76f..98f13750bf26c41c8f908ccd98e4af5e451d7e76 100644 (file)
--- 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)

diff --git a/src/bin/psql/print.c b/src/bin/psql/print.c
index d62b46d01035ea6cac366be3e32f01ebbb368659..1d73fd5790f39a8c16d6b3e5e94fd3a02ffba86f 100644 (file)
--- a/src/bin/psql/print.c
+++ b/src/bin/psql/print.c
@@ -3,7 +3,7 @@
  *
  * Copyright (c) 2000-2010, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/bin/psql/print.c,v 1.124 2010/03/01 21:27:26 heikki Exp $
+ * $PostgreSQL: pgsql/src/bin/psql/print.c,v 1.125 2010/05/08 16:39:52 tgl Exp $
  */
 #include "postgres_fe.h"
 
@@ -252,6 +252,20 @@ format_numeric_locale(const char *my_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               */
 /*************************/
@@ -913,14 +927,16 @@ 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);
                                        }
 
                                        bytes_output[j] += bytes_to_output;

diff --git a/src/interfaces/ecpg/ecpglib/error.c b/src/interfaces/ecpg/ecpglib/error.c
index ea48f082dcab50ad1364d6d15b8909912db25044..5451fd298198fbf27c4c1fcfd781f0a90a2a18c2 100644 (file)
--- a/src/interfaces/ecpg/ecpglib/error.c
+++ b/src/interfaces/ecpg/ecpglib/error.c
@@ -1,4 +1,4 @@
-/* $PostgreSQL: pgsql/src/interfaces/ecpg/ecpglib/error.c,v 1.25 2010/03/08 12:15:24 meskes Exp $ */
+/* $PostgreSQL: pgsql/src/interfaces/ecpg/ecpglib/error.c,v 1.26 2010/05/08 16:39:52 tgl Exp $ */
 
 #define POSTGRES_ECPG_INTERNAL
 #include "postgres_fe.h"
@@ -332,6 +332,7 @@ ecpg_raise_backend(int line, PGresult *result, PGconn *conn, int compat)
        else
                sqlca->sqlcode = ECPG_PGSQL;
 
+       /* %.*s is safe here as long as sqlstate is all-ASCII */
        ecpg_log("raising sqlstate %.*s (sqlcode %d): %s\n",
                         sizeof(sqlca->sqlstate), sqlca->sqlstate, sqlca->sqlcode, sqlca->sqlerrm.sqlerrmc);
 

diff --git a/src/interfaces/ecpg/pgtypeslib/dt_common.c b/src/interfaces/ecpg/pgtypeslib/dt_common.c
index 9fb6357ddafcef0caf5e793a3e8b4660273df5cd..dc5fbe7fd96b2b19850f429de6d866e2bc643fe7 100644 (file)
--- a/src/interfaces/ecpg/pgtypeslib/dt_common.c
+++ b/src/interfaces/ecpg/pgtypeslib/dt_common.c
@@ -1,4 +1,4 @@
-/* $PostgreSQL: pgsql/src/interfaces/ecpg/pgtypeslib/dt_common.c,v 1.51 2009/06/11 14:49:13 momjian Exp $ */
+/* $PostgreSQL: pgsql/src/interfaces/ecpg/pgtypeslib/dt_common.c,v 1.52 2010/05/08 16:39:52 tgl Exp $ */
 
 #include "postgres_fe.h"
 
@@ -855,6 +855,14 @@ EncodeDateTime(struct tm * tm, fsec_t fsec, int *tzp, char **tzn, int style, cha
                        if (tm->tm_year <= 0)
                                sprintf(str + strlen(str), " BC");
 
+                       /*
+                        * Note: the uses of %.*s in this function would be unportable
+                        * if the timezone names ever contain non-ASCII characters,
+                        * since some platforms think the string length is measured
+                        * in characters not bytes.  However, all TZ abbreviations in
+                        * the Olson database are plain ASCII.
+                        */
+
                        if (tzp != NULL && tm->tm_isdst >= 0)
                        {
                                if (*tzn != NULL)

diff --git a/src/interfaces/libpq/fe-misc.c b/src/interfaces/libpq/fe-misc.c
index 5176cf562512a20d09eb5bb61729ab115ecad137..096e0d84a7a1e016751b97c812b90342c0d19694 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 1.141 2010/01/02 16:58:12 momjian Exp $
+ *       $PostgreSQL: pgsql/src/interfaces/libpq/fe-misc.c,v 1.142 2010/05/08 16:39:53 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;
 }