Make postgres.bki use the same literal-string syntax as postgresql.conf.

The BKI file's string quoting conventions were previously quite weird,
perhaps as a result of repurposing a function built to scan
single-quoted strings to scan double-quoted ones.  Change to use the
same rules as we use in GUC files, allowing some simplifications in
genbki.pl and initdb.c.

While at it, completely remove the backend's scanstr() function, which
was essentially a duplicate of the string dequoting code in guc-file.l.
Instead export that one (under a less generic name than it had) and let
bootscanner.l use it.  Now we can clarify that scansup.c exists only to
support the main lexer. We could alternatively have removed GUC_scanstr,
but this way seems better since the previous arrangement could mislead
a reader into thinking that scanstr() had something to do with the main
lexer's handling of string literals.  Maybe it did once, but if so it
was a long time ago.

This patch does not bump catversion, since the initially-installed
catalog contents don't change.  Note however that successful initdb
after applying this patch will require up-to-date postgres.bki as well
as postgres and initdb executables.

In passing, remove a bunch of very-long-obsolete #include's in
bootparse.y and bootscanner.l.

John Naylor

Discussion: https://postgr.es/m/CACPNZCtDpd18T0KATTmCggO2GdVC4ow86ypiq5ENff1VnauL8g@mail.gmail.com

5 files changed, 16 insertions, 147 deletions

diff --git a/src/backend/bootstrap/bootparse.y b/src/backend/bootstrap/bootparse.y
index 5eaca279ee8..6bb0c6ed1ea 100644
--- a/src/backend/bootstrap/bootparse.y
+++ b/src/backend/bootstrap/bootparse.y
@@ -18,16 +18,10 @@
 
 #include <unistd.h>
 
-#include "access/attnum.h"
-#include "access/htup.h"
-#include "access/itup.h"
-#include "access/tupdesc.h"
 #include "bootstrap/bootstrap.h"
-#include "catalog/catalog.h"
 #include "catalog/heap.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_am.h"
-#include "catalog/pg_attribute.h"
 #include "catalog/pg_authid.h"
 #include "catalog/pg_class.h"
 #include "catalog/pg_namespace.h"
@@ -36,20 +30,7 @@
 #include "commands/defrem.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
-#include "nodes/nodes.h"
-#include "nodes/parsenodes.h"
-#include "nodes/pg_list.h"
-#include "nodes/primnodes.h"
-#include "rewrite/prs2lock.h"
-#include "storage/block.h"
-#include "storage/fd.h"
-#include "storage/ipc.h"
-#include "storage/itemptr.h"
-#include "storage/off.h"
-#include "storage/smgr.h"
-#include "tcop/dest.h"
 #include "utils/memutils.h"
-#include "utils/rel.h"
 
 
 /*
diff --git a/src/backend/bootstrap/bootscanner.l b/src/backend/bootstrap/bootscanner.l
index 1048e70d053..6a0bed6c8d6 100644
--- a/src/backend/bootstrap/bootscanner.l
+++ b/src/backend/bootstrap/bootscanner.l
@@ -15,25 +15,8 @@
  */
 #include "postgres.h"
 
-#include "access/attnum.h"
-#include "access/htup.h"
-#include "access/itup.h"
-#include "access/tupdesc.h"
 #include "bootstrap/bootstrap.h"
-#include "catalog/pg_am.h"
-#include "catalog/pg_attribute.h"
-#include "catalog/pg_class.h"
-#include "nodes/nodes.h"
-#include "nodes/parsenodes.h"
-#include "nodes/pg_list.h"
-#include "nodes/primnodes.h"
-#include "parser/scansup.h"
-#include "rewrite/prs2lock.h"
-#include "storage/block.h"
-#include "storage/fd.h"
-#include "storage/itemptr.h"
-#include "storage/off.h"
-#include "utils/rel.h"
+#include "utils/guc.h"
 
 /* Not needed now that this file is compiled as part of bootparse. */
 /* #include "bootparse.h" */
@@ -66,7 +49,7 @@ static int	yyline = 1;			/* line number for error reporting */
 
 
 id		[-A-Za-z0-9_]+
-sid		\"([^\"])*\"
+sid		\'([^']|\'\')*\'
 
 /*
  * Keyword tokens return the keyword text (as a constant string) in yylval.kw,
@@ -120,14 +103,12 @@ NOT				{ yylval.kw = "NOT"; return XNOT; }
 NULL			{ yylval.kw = "NULL"; return XNULL; }
 
 {id}			{
-					yylval.str = scanstr(yytext);
+					yylval.str = pstrdup(yytext);
 					return ID;
 				}
 {sid}			{
-					/* leading and trailing quotes are not passed to scanstr */
-					yytext[strlen(yytext) - 1] = '\0';
-					yylval.str = scanstr(yytext+1);
-					yytext[strlen(yytext)] = '"';	/* restore yytext */
+					/* strip quotes and escapes */
+					yylval.str = DeescapeQuotedString(yytext);
 					return ID;
 				}
 
diff --git a/src/backend/catalog/genbki.pl b/src/backend/catalog/genbki.pl
index dc5f442397a..ef3105af44b 100644
--- a/src/backend/catalog/genbki.pl
+++ b/src/backend/catalog/genbki.pl
@@ -845,17 +845,15 @@ sub print_bki_insert
 		# since that represents a NUL char in C code.
 		$bki_value = '' if $bki_value eq '\0';
 
-		# Handle single quotes by doubling them, and double quotes by
-		# converting them to octal escapes, because that's what the
+		# Handle single quotes by doubling them, because that's what the
 		# bootstrap scanner requires.  We do not process backslashes
 		# specially; this allows escape-string-style backslash escapes
 		# to be used in catalog data.
 		$bki_value =~ s/'/''/g;
-		$bki_value =~ s/"/\\042/g;
 
 		# Quote value if needed.  We need not quote values that satisfy
 		# the "id" pattern in bootscanner.l, currently "[-A-Za-z0-9_]+".
-		$bki_value = sprintf(qq'"%s"', $bki_value)
+		$bki_value = sprintf("'%s'", $bki_value)
 		  if length($bki_value) == 0
 		  or $bki_value =~ /[^-A-Za-z0-9_]/;
 
diff --git a/src/backend/parser/scansup.c b/src/backend/parser/scansup.c
index cac70d5df7a..d07cbafcee7 100644
--- a/src/backend/parser/scansup.c
+++ b/src/backend/parser/scansup.c
@@ -1,8 +1,7 @@
 /*-------------------------------------------------------------------------
  *
  * scansup.c
- *	  support routines for the lex/flex scanner, used by both the normal
- * backend as well as the bootstrap backend
+ *	  scanner support routines used by the core lexer
  *
  * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
@@ -20,98 +19,6 @@
 #include "mb/pg_wchar.h"
 #include "parser/scansup.h"
 
-/* ----------------
- *		scanstr
- *
- * if the string passed in has escaped codes, map the escape codes to actual
- * chars
- *
- * the string returned is palloc'd and should eventually be pfree'd by the
- * caller!
- * ----------------
- */
-
-char *
-scanstr(const char *s)
-{
-	char	   *newStr;
-	int			len,
-				i,
-				j;
-
-	if (s == NULL || s[0] == '\0')
-		return pstrdup("");
-
-	len = strlen(s);
-
-	newStr = palloc(len + 1);	/* string cannot get longer */
-
-	for (i = 0, j = 0; i < len; i++)
-	{
-		if (s[i] == '\'')
-		{
-			/*
-			 * Note: if scanner is working right, unescaped quotes can only
-			 * appear in pairs, so there should be another character.
-			 */
-			i++;
-			/* The bootstrap parser is not as smart, so check here. */
-			Assert(s[i] == '\'');
-			newStr[j] = s[i];
-		}
-		else if (s[i] == '\\')
-		{
-			i++;
-			switch (s[i])
-			{
-				case 'b':
-					newStr[j] = '\b';
-					break;
-				case 'f':
-					newStr[j] = '\f';
-					break;
-				case 'n':
-					newStr[j] = '\n';
-					break;
-				case 'r':
-					newStr[j] = '\r';
-					break;
-				case 't':
-					newStr[j] = '\t';
-					break;
-				case '0':
-				case '1':
-				case '2':
-				case '3':
-				case '4':
-				case '5':
-				case '6':
-				case '7':
-					{
-						int			k;
-						long		octVal = 0;
-
-						for (k = 0;
-							 s[i + k] >= '0' && s[i + k] <= '7' && k < 3;
-							 k++)
-							octVal = (octVal << 3) + (s[i + k] - '0');
-						i += k - 1;
-						newStr[j] = ((char) octVal);
-					}
-					break;
-				default:
-					newStr[j] = s[i];
-					break;
-			}					/* switch */
-		}						/* s[i] == '\\' */
-		else
-			newStr[j] = s[i];
-		j++;
-	}
-	newStr[j] = '\0';
-	return newStr;
-}
-
 
 /*
  * downcase_truncate_identifier() --- do appropriate downcasing and
diff --git a/src/backend/utils/misc/guc-file.l b/src/backend/utils/misc/guc-file.l
index 268b7455283..c98e2202951 100644
--- a/src/backend/utils/misc/guc-file.l
+++ b/src/backend/utils/misc/guc-file.l
@@ -55,7 +55,6 @@ static void record_config_file_error(const char *errmsg,
 						 ConfigVariable **tail_p);
 
 static int	GUC_flex_fatal(const char *msg);
-static char *GUC_scanstr(const char *s);
 
 /* LCOV_EXCL_START */
 
@@ -797,7 +796,7 @@ ParseConfigFp(FILE *fp, const char *config_file, int depth, int elevel,
 			token != GUC_UNQUOTED_STRING)
 			goto parse_error;
 		if (token == GUC_STRING)	/* strip quotes and escapes */
-			opt_value = GUC_scanstr(yytext);
+			opt_value = DeescapeQuotedString(yytext);
 		else
 			opt_value = pstrdup(yytext);
 
@@ -1132,22 +1131,25 @@ FreeConfigVariable(ConfigVariable *item)
 
 
 /*
- *		scanstr
+ *		DeescapeQuotedString
  *
  * Strip the quotes surrounding the given string, and collapse any embedded
  * '' sequences and backslash escapes.
  *
- * the string returned is palloc'd and should eventually be pfree'd by the
+ * The string returned is palloc'd and should eventually be pfree'd by the
  * caller.
+ *
+ * This is exported because it is also used by the bootstrap scanner.
  */
-static char *
-GUC_scanstr(const char *s)
+char *
+DeescapeQuotedString(const char *s)
 {
 	char	   *newStr;
 	int			len,
 				i,
 				j;
 
+	/* We just Assert that there are leading and trailing quotes */
 	Assert(s != NULL && s[0] == '\'');
 	len = strlen(s);
 	Assert(len >= 2);