diff options
| author |   anton <anton@openbsd.org> | 2020-12-11 07:27:55 +0000 |
|---|---|---|
| committer | anton <anton@openbsd.org> | 2020-12-11 07:27:55 +0000 |
| commit | 85e665dc337dc8951ed1d2e14417b82acd4995e5 (patch) | |
| tree | 447388306ed67f473f595048c87d6bc96a33c807 | |
| parent | pass down the `skip' flag to the mountfs() function in the case of (diff) | |
| download | wireguard-openbsd-85e665dc337dc8951ed1d2e14417b82acd4995e5.tar.xz wireguard-openbsd-85e665dc337dc8951ed1d2e14417b82acd4995e5.zip | |
Tracing syscalls which conflict with reserved bt(5) keywords currently
causes btrace to reject such programs. An example is exit which is both
a syscall and a builtin btrace function. Pointed out by bluhm@
To resolve the conflict, make use of a lexer backdoor. A concept
described in the original yacc paper and also found in other yacc
parsers in our tree.
ok bluhm@ mpi@
| -rw-r--r-- | usr.sbin/btrace/bt_parse.y | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/usr.sbin/btrace/bt_parse.y b/usr.sbin/btrace/bt_parse.y index ee4ac9b259d..520b544040f 100644 --- a/usr.sbin/btrace/bt_parse.y +++ b/usr.sbin/btrace/bt_parse.y @@ -1,4 +1,4 @@ -/* $OpenBSD: bt_parse.y,v 1.19 2020/12/07 20:14:35 anton Exp $ */ +/* $OpenBSD: bt_parse.y,v 1.20 2020/12/11 07:27:55 anton Exp $ */ /* * Copyright (c) 2019 - 2020 Martin Pieuchot <mpi@openbsd.org> @@ -98,6 +98,8 @@ typedef struct { static void yyerror(const char *, ...); static int yylex(void); + +static int pflag; %} %token ERROR OP_EQ OP_NEQ BEGIN END HZ @@ -112,7 +114,7 @@ static int yylex(void); %type <v.i> filterval oper builtin %type <v.i> BUILTIN F_DELETE F_PRINT FUNC0 FUNC1 FUNCN OP1 OP4 %type <v.i> MOP0 MOP1 -%type <v.probe> probe +%type <v.probe> probe probeval %type <v.filter> predicate %type <v.stmt> action stmt stmtlist %type <v.arg> expr vargs map mexpr printargs term @@ -138,7 +140,9 @@ beginend : BEGIN { $$ = B_RT_BEGIN; } | END { $$ = B_RT_END; } ; -probe : STRING ':' STRING ':' STRING { $$ = bp_new($1, $3, $5, 0); } +probe : { pflag = 1; } probeval { $$ = $2; pflag = 0; } + +probeval : STRING ':' STRING ':' STRING { $$ = bp_new($1, $3, $5, 0); } | STRING ':' HZ ':' NUMBER { $$ = bp_new($1, "hz", NULL, $5); } ; @@ -784,6 +788,15 @@ again: err(1, "%s", __func__); return STRING; } + if (pflag) { + /* + * Probe lexer backdoor, interpret the token as a string + * rather than a keyword. Otherwise, reserved keywords + * would conflict with syscall names. + */ + yylval.v.string = kwp->word; + return STRING; + } yylval.v.i = kwp->type; return kwp->token; } |