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File: [cvsweb.bsd.lv] / mandoc / eqn_parse.h (download)
Revision 1.4, Wed Apr 13 20:26:19 2022 UTC (2 years, 6 months ago) by schwarze
To prevent infinite recursion while expanding eqn(7) definitions, we must not reset the recursion counter when moving beyond the end of the *previous* expansion, but we may only do so when moving beyond the rightmost position reached by *any* expansion in the current equation. This matters because definitions can nest; consider: .EQ define inner "content" define outer "inner outer" outer .EN This endless loop was found by tb@ using afl(1). Incidentally, GNU eqn(1) also performs an infinite loop in this situation and then crashes when memory runs out, but that's not an excuse for nasty behaviour of mandoc(1). While here, consistently print the expanded content even when the expansion is finally truncated. While that is not likely to help end-users, it may help authors of eqn(7) code to understand what's going on. Besides, it sends a very clear signal that something is amiss, which was easy to miss in the past unless people enabled -W error or used -T lint. |
/* $Id: eqn_parse.h,v 1.4 2022/04/13 20:26:19 schwarze Exp $ */ /* * Copyright (c) 2014, 2017, 2018, 2022 Ingo Schwarze <schwarze@openbsd.org> * Copyright (c) 2011 Kristaps Dzonsons <kristaps@bsd.lv> * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. * * External interface of the eqn(7) parser. * For use in the roff(7) and eqn(7) parsers only. */ struct roff_node; struct eqn_box; struct eqn_def; struct eqn_node { struct roff_node *node; /* Syntax tree of this equation. */ struct eqn_def *defs; /* Array of definitions. */ char *data; /* Source code of this equation. */ char *start; /* First byte of the current token. */ char *end; /* First byte of the next token. */ size_t defsz; /* Number of definitions. */ size_t sz; /* Length of the source code. */ size_t toksz; /* Length of the current token. */ int sublen; /* End of rightmost substitution, so far. */ int subcnt; /* Number of recursive substitutions. */ int gsize; /* Default point size. */ int delim; /* In-line delimiters enabled. */ char odelim; /* In-line opening delimiter. */ char cdelim; /* In-line closing delimiter. */ }; struct eqn_node *eqn_alloc(void); struct eqn_box *eqn_box_new(void); void eqn_box_free(struct eqn_box *); void eqn_free(struct eqn_node *); void eqn_parse(struct eqn_node *); void eqn_read(struct eqn_node *, const char *); void eqn_reset(struct eqn_node *);