d62627487
Denys Vlasenko
2021-07-14
Subject
awk: tighten parsing - disallow extra semicolons
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editors/awk.c+24 -16
| @@ -1634,7 +1634,7 @@ static void chain_group(void) | |
| debug_printf_parse("%s: ST_FOR\n", __func__); | |
| next_token(TC_LPAREN); | |
| n2 = parse_expr(TC_SEMICOL | TC_RPAREN); | |
| - | if (t_tclass & TC_RPAREN) { /* for-in */ |
| + | if (t_tclass & TC_RPAREN) { /* for (I in ARRAY) */ |
| if (!n2 || n2->info != TI_IN) | |
| syntax_error(EMSG_UNEXP_TOKEN); | |
| n = chain_node(OC_WALKINIT | VV); | |
| @@ -1700,20 +1700,15 @@ static void parse_program(char *p) | |
| for (;;) { | |
| uint32_t tclass; | |
| - | tclass = next_token(TC_EOF | TS_OPSEQ | TC_LBRACE | |
| - | TC_SEMICOL | TC_NEWLINE | TC_BEGIN | TC_END | TC_FUNCDECL); |
| - | |
| + | tclass = next_token(TS_OPSEQ | TC_LBRACE | TC_BEGIN | TC_END | TC_FUNCDECL |
| + | | TC_EOF | TC_NEWLINE /* but not TC_SEMICOL */); |
| + | got_tok: |
| if (tclass == TC_EOF) { | |
| debug_printf_parse("%s: TC_EOF\n", __func__); | |
| break; | |
| } | |
| - | if (tclass & (TC_SEMICOL | TC_NEWLINE)) { |
| - | debug_printf_parse("%s: TC_SEMICOL | TC_NEWLINE\n", __func__); |
| - | //NB: gawk allows many newlines, but does not allow more than one semicolon: |
| - | // BEGIN {...}<newline>;<newline>; |
| - | //would complain "each rule must have a pattern or an action part". |
| - | //Same message for |
| - | // ; BEGIN {...} |
| + | if (tclass == TC_NEWLINE) { |
| + | debug_printf_parse("%s: TC_NEWLINE\n", __func__); |
| continue; | |
| } | |
| if (tclass == TC_BEGIN) { | |
| @@ -1722,7 +1717,7 @@ static void parse_program(char *p) | |
| /* ensure there is no newline between BEGIN and { */ | |
| next_token(TC_LBRACE); | |
| chain_until_rbrace(); | |
| - | continue; |
| + | goto next_tok; |
| } | |
| if (tclass == TC_END) { | |
| debug_printf_parse("%s: TC_END\n", __func__); | |
| @@ -1730,7 +1725,7 @@ static void parse_program(char *p) | |
| /* ensure there is no newline between END and { */ | |
| next_token(TC_LBRACE); | |
| chain_until_rbrace(); | |
| - | continue; |
| + | goto next_tok; |
| } | |
| if (tclass == TC_FUNCDECL) { | |
| func *f; | |
| @@ -1765,7 +1760,7 @@ static void parse_program(char *p) | |
| continue; | |
| chain_until_rbrace(); | |
| hash_clear(ahash); | |
| - | continue; |
| + | goto next_tok; |
| } | |
| seq = &mainseq; | |
| if (tclass & TS_OPSEQ) { | |
| @@ -1784,12 +1779,25 @@ static void parse_program(char *p) | |
| chain_node(OC_PRINT); | |
| } | |
| cn->r.n = mainseq.last; | |
| - | continue; |
| + | goto next_tok; |
| } | |
| /* tclass == TC_LBRACE */ | |
| debug_printf_parse("%s: TC_LBRACE(?)\n", __func__); | |
| chain_until_rbrace(); | |
| - | } |
| + | next_tok: |
| + | /* Same as next_token() at the top of the loop, + TC_SEMICOL */ |
| + | tclass = next_token(TS_OPSEQ | TC_LBRACE | TC_BEGIN | TC_END | TC_FUNCDECL |
| + | | TC_EOF | TC_NEWLINE | TC_SEMICOL); |
| + | /* gawk allows many newlines, but does not allow more than one semicolon: |
| + | * BEGIN {...}<newline>;<newline>; |
| + | * would complain "each rule must have a pattern or an action part". |
| + | * Same message for |
| + | * ; BEGIN {...} |
| + | */ |
| + | if (tclass != TC_SEMICOL) |
| + | goto got_tok; /* use this token */ |
| + | /* else: loop back - ate the semicolon, get and use _next_ token */ |
| + | } /* for (;;) */ |
| } | |