From 3e4bacb171001644583ac14e29ae1b09ce818c92 Mon Sep 17 00:00:00 2001 From: Peter Eisentraut Date: Thu, 19 Dec 2024 15:37:44 +0100 Subject: [PATCH] bootstrap: pure parser and reentrant scanner Use the flex %option reentrant and the bison option %pure-parser to make the generated scanner and parser pure, reentrant, and thread-safe. Make the generated scanner use palloc() etc. instead of malloc() etc. For the bootstrap scanner and parser, reentrancy and memory management aren't that important, but we make this change here anyway so that all the scanners and parsers in the backend use a similar set of options and APIs. Reviewed-by: Heikki Linnakangas Reviewed-by: Andreas Karlsson Discussion: https://www.postgresql.org/message-id/flat/eb6faeac-2a8a-4b69-9189-c33c520e5b7b@eisentraut.org --- src/backend/bootstrap/bootparse.y | 9 +-- src/backend/bootstrap/bootscanner.l | 91 +++++++++++++++++++---------- src/backend/bootstrap/bootstrap.c | 6 +- src/include/bootstrap/bootstrap.h | 12 +++- 4 files changed, 80 insertions(+), 38 deletions(-) diff --git a/src/backend/bootstrap/bootparse.y b/src/backend/bootstrap/bootparse.y index 73a7592fb71..05ef26c07d0 100644 --- a/src/backend/bootstrap/bootparse.y +++ b/src/backend/bootstrap/bootparse.y @@ -34,10 +34,6 @@ #include "bootparse.h" -/* silence -Wmissing-variable-declarations */ -extern int boot_yychar; -extern int boot_yynerrs; - /* * Bison doesn't allocate anything that needs to live across parser calls, @@ -81,6 +77,9 @@ static int num_columns_read = 0; %} +%parse-param {yyscan_t yyscanner} +%lex-param {yyscan_t yyscanner} +%pure-parser %expect 0 %name-prefix="boot_yy" @@ -141,6 +140,8 @@ Boot_OpenStmt: do_start(); boot_openrel($2); do_end(); + + (void) yynerrs; /* suppress compiler warning */ } ; diff --git a/src/backend/bootstrap/bootscanner.l b/src/backend/bootstrap/bootscanner.l index 31d63ff3015..ad33b4e3fd8 100644 --- a/src/backend/bootstrap/bootscanner.l +++ b/src/backend/bootstrap/bootscanner.l @@ -39,17 +39,19 @@ fprintf_to_ereport(const char *fmt, const char *msg) ereport(ERROR, (errmsg_internal("%s", msg))); } - -static int yyline = 1; /* line number for error reporting */ - %} +%option reentrant +%option bison-bridge %option 8bit %option never-interactive %option nodefault %option noinput %option nounput %option noyywrap +%option noyyalloc +%option noyyrealloc +%option noyyfree %option warn %option prefix="boot_yy" @@ -58,7 +60,7 @@ id [-A-Za-z0-9_]+ sid \'([^']|\'\')*\' /* - * Keyword tokens return the keyword text (as a constant string) in boot_yylval.kw, + * Keyword tokens return the keyword text (as a constant string) in yylval->kw, * just in case that's needed because we want to treat the keyword as an * unreserved identifier. Note that _null_ is not treated as a keyword * for this purpose; it's the one "reserved word" in the bootstrap syntax. @@ -66,23 +68,23 @@ sid \'([^']|\'\')*\' * Notice that all the keywords are case-sensitive, and for historical * reasons some must be upper case. * - * String tokens return a palloc'd string in boot_yylval.str. + * String tokens return a palloc'd string in yylval->str. */ %% -open { boot_yylval.kw = "open"; return OPEN; } +open { yylval->kw = "open"; return OPEN; } -close { boot_yylval.kw = "close"; return XCLOSE; } +close { yylval->kw = "close"; return XCLOSE; } -create { boot_yylval.kw = "create"; return XCREATE; } +create { yylval->kw = "create"; return XCREATE; } -OID { boot_yylval.kw = "OID"; return OBJ_ID; } -bootstrap { boot_yylval.kw = "bootstrap"; return XBOOTSTRAP; } -shared_relation { boot_yylval.kw = "shared_relation"; return XSHARED_RELATION; } -rowtype_oid { boot_yylval.kw = "rowtype_oid"; return XROWTYPE_OID; } +OID { yylval->kw = "OID"; return OBJ_ID; } +bootstrap { yylval->kw = "bootstrap"; return XBOOTSTRAP; } +shared_relation { yylval->kw = "shared_relation"; return XSHARED_RELATION; } +rowtype_oid { yylval->kw = "rowtype_oid"; return XROWTYPE_OID; } -insert { boot_yylval.kw = "insert"; return INSERT_TUPLE; } +insert { yylval->kw = "insert"; return INSERT_TUPLE; } _null_ { return NULLVAL; } @@ -91,35 +93,35 @@ _null_ { return NULLVAL; } "(" { return LPAREN; } ")" { return RPAREN; } -[\n] { yyline++; } +[\n] { yylineno++; } [\r\t ] ; ^\#[^\n]* ; /* drop everything after "#" for comments */ -declare { boot_yylval.kw = "declare"; return XDECLARE; } -build { boot_yylval.kw = "build"; return XBUILD; } -indices { boot_yylval.kw = "indices"; return INDICES; } -unique { boot_yylval.kw = "unique"; return UNIQUE; } -index { boot_yylval.kw = "index"; return INDEX; } -on { boot_yylval.kw = "on"; return ON; } -using { boot_yylval.kw = "using"; return USING; } -toast { boot_yylval.kw = "toast"; return XTOAST; } -FORCE { boot_yylval.kw = "FORCE"; return XFORCE; } -NOT { boot_yylval.kw = "NOT"; return XNOT; } -NULL { boot_yylval.kw = "NULL"; return XNULL; } +declare { yylval->kw = "declare"; return XDECLARE; } +build { yylval->kw = "build"; return XBUILD; } +indices { yylval->kw = "indices"; return INDICES; } +unique { yylval->kw = "unique"; return UNIQUE; } +index { yylval->kw = "index"; return INDEX; } +on { yylval->kw = "on"; return ON; } +using { yylval->kw = "using"; return USING; } +toast { yylval->kw = "toast"; return XTOAST; } +FORCE { yylval->kw = "FORCE"; return XFORCE; } +NOT { yylval->kw = "NOT"; return XNOT; } +NULL { yylval->kw = "NULL"; return XNULL; } {id} { - boot_yylval.str = pstrdup(yytext); + yylval->str = pstrdup(yytext); return ID; } {sid} { /* strip quotes and escapes */ - boot_yylval.str = DeescapeQuotedString(yytext); + yylval->str = DeescapeQuotedString(yytext); return ID; } . { - elog(ERROR, "syntax error at line %d: unexpected character \"%s\"", yyline, yytext); + elog(ERROR, "syntax error at line %d: unexpected character \"%s\"", yylineno, yytext); } %% @@ -127,7 +129,36 @@ NULL { boot_yylval.kw = "NULL"; return XNULL; } /* LCOV_EXCL_STOP */ void -boot_yyerror(const char *message) +boot_yyerror(yyscan_t yyscanner, const char *message) { - elog(ERROR, "%s at line %d", message, yyline); + struct yyguts_t * yyg = (struct yyguts_t *) yyscanner; /* needed for yylineno macro */ + + elog(ERROR, "%s at line %d", message, yylineno); +} + +/* + * Interface functions to make flex use palloc() instead of malloc(). + * It'd be better to make these static, but flex insists otherwise. + */ + +void * +yyalloc(yy_size_t size, yyscan_t yyscanner) +{ + return palloc(size); +} + +void * +yyrealloc(void *ptr, yy_size_t size, yyscan_t yyscanner) +{ + if (ptr) + return repalloc(ptr, size); + else + return palloc(size); +} + +void +yyfree(void *ptr, yyscan_t yyscanner) +{ + if (ptr) + pfree(ptr); } diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c index f3a7a007f77..d35ccab4873 100644 --- a/src/backend/bootstrap/bootstrap.c +++ b/src/backend/bootstrap/bootstrap.c @@ -202,6 +202,7 @@ BootstrapModeMain(int argc, char *argv[], bool check_only) int flag; char *userDoption = NULL; uint32 bootstrap_data_checksum_version = 0; /* No checksum */ + yyscan_t scanner; Assert(!IsUnderPostmaster); @@ -378,11 +379,14 @@ BootstrapModeMain(int argc, char *argv[], bool check_only) Nulls[i] = false; } + if (boot_yylex_init(&scanner) != 0) + elog(ERROR, "yylex_init() failed: %m"); + /* * Process bootstrap input. */ StartTransactionCommand(); - boot_yyparse(); + boot_yyparse(scanner); CommitTransactionCommand(); /* diff --git a/src/include/bootstrap/bootstrap.h b/src/include/bootstrap/bootstrap.h index 73b78b31335..33035d4ed82 100644 --- a/src/include/bootstrap/bootstrap.h +++ b/src/include/bootstrap/bootstrap.h @@ -55,9 +55,15 @@ extern void boot_get_type_io_data(Oid typid, Oid *typinput, Oid *typoutput); -extern int boot_yyparse(void); +union YYSTYPE; +#ifndef YY_TYPEDEF_YY_SCANNER_T +#define YY_TYPEDEF_YY_SCANNER_T +typedef void *yyscan_t; +#endif -extern int boot_yylex(void); -extern void boot_yyerror(const char *message) pg_attribute_noreturn(); +extern int boot_yyparse(yyscan_t yyscanner); +extern int boot_yylex_init(yyscan_t *yyscannerp); +extern int boot_yylex(union YYSTYPE *yylval_param, yyscan_t yyscanner); +extern void boot_yyerror(yyscan_t yyscanner, const char *message) pg_attribute_noreturn(); #endif /* BOOTSTRAP_H */