From 95fac5e87304a50f7e93de94f0f682ec06565006 Mon Sep 17 00:00:00 2001 From: cinap_lenrek Date: Thu, 5 Sep 2013 00:55:58 +0200 Subject: [PATCH] libhtml: fix potential linked list corruption the difficulty is freeing items while parsing because items might already be linked into various linked lists like in docinfo.images or form.fiels. so we link images, tables and formfields to the docinfo as the final step of getitems() pass using the new recursive function linkitems(). as only reachable items get linked theres no danger of dangeling pointers. --- sys/include/html.h | 1 - sys/src/libhtml/build.c | 107 ++++++++++++++++++++++++++-------------- 2 files changed, 69 insertions(+), 39 deletions(-) diff --git a/sys/include/html.h b/sys/include/html.h index 3e3f9ed19..57d227bf6 100644 --- a/sys/include/html.h +++ b/sys/include/html.h @@ -253,7 +253,6 @@ struct Ifloat int y; /* y coord of top */ uchar side; /* margin it floats to: ALleft or ALright */ uchar infloats; /* true if this has been added to a lay.floats */ - Ifloat* nextfloat; /* in list of floats */ }; diff --git a/sys/src/libhtml/build.c b/sys/src/libhtml/build.c index 50e5b1624..7b99d64a1 100644 --- a/sys/src/libhtml/build.c +++ b/sys/src/libhtml/build.c @@ -54,6 +54,7 @@ struct ItemSource int ntables; int nanchors; int nframes; + Formfield* curfield; Form* curform; Map* curmap; Table* tabstk; @@ -358,6 +359,7 @@ newitemsource(Docinfo* di) is->ntables = 0; is->nanchors = 0; is->nframes = 0; + is->curfield = nil; is->curform = nil; is->curmap = nil; is->tabstk = nil; @@ -365,6 +367,62 @@ newitemsource(Docinfo* di) return is; } +static void +linkitems(Docinfo *di, Item *it) +{ + Formfield *ff; + Tablecell *c; + Table *tt; + + while(it != nil){ + switch(it->tag) { + case Iimagetag: + /* link image to docinfo */ + ((Iimage*)it)->nextimage = di->images; + di->images = (Iimage*)it; + break; + case Iformfieldtag: + /* link formfield to form */ + ff = ((Iformfield*)it)->formfield; + if(ff != nil && ff->form != nil){ + for(ff = ff->form->fields; ff != nil; ff = ff->next){ + if(ff == ((Iformfield*)it)->formfield) + goto Next; + if(ff->next == nil) + break; + } + ((Iformfield*)it)->formfield->next = nil; + if(ff != nil){ + ff->next = ((Iformfield*)it)->formfield; + ff = ff->next; + } else { + ff = ((Iformfield*)it)->formfield; + ff->form->fields = ff; + } + linkitems(di, ff->image); + } + break; + case Itabletag: + /* link table to docinfo */ + tt = ((Itable*)it)->table; + if(tt == nil) + break; + tt->tabletok = nil; + tt->next = di->tables; + di->tables = tt; + linkitems(di, tt->caption); + for(c = tt->cells; c != nil; c = c->next) + linkitems(di, c->content); + break; + case Ifloattag: + linkitems(di, ((Ifloat*)it)->item); + break; + } + Next: + it = it->next; + } +} + static Item *getitems(ItemSource* is, uchar* data, int datalen); // Parse an html document and create a list of layout items. @@ -453,7 +511,6 @@ getitems(ItemSource* is, uchar* data, int datalen) Rune* script; Map* map; Form* frm; - Iimage* ii; Kidinfo* kd; Kidinfo* ks; Kidinfo* pks; @@ -693,19 +750,9 @@ getitems(ItemSource* is, uchar* data, int datalen) bg = makebackground(nil, acolorval(tok, Abgcolor, di->background.color)); bgurl = aurlval(tok, Abackground, nil, di->base); if(bgurl != nil) { - if(di->backgrounditem != nil){ - Iimage **ii; - for(ii=&di->images; *ii != nil; ii = &((*ii)->nextimage)){ - if(*ii == di->backgrounditem){ - *ii = di->backgrounditem->nextimage; - break; - } - } + if(di->backgrounditem != nil) freeitem(di->backgrounditem); - } di->backgrounditem = (Iimage*)newiimage(bgurl, nil, ALnone, 0, 0, 0, 0, 0, 0, nil); - di->backgrounditem->nextimage = di->images; - di->images = di->backgrounditem; } ps->curbg = bg; di->background = bg; @@ -902,8 +949,6 @@ getitems(ItemSource* is, uchar* data, int datalen) fprint(2, "warning: unexpected \n"); continue; } - // put fields back in input order - is->curform->fields = (Formfield*)_revlist((List*)is->curform->fields); is->curform = nil; break; @@ -1092,10 +1137,6 @@ getitems(ItemSource* is, uchar* data, int datalen) ps->skipwhite = 0; additem(ps, img, tok); } - if(!ps->skipping) { - ((Iimage*)img)->nextimage = di->images; - di->images = (Iimage*)img; - } ps->curanchor = oldcuranchor; break; @@ -1107,7 +1148,7 @@ getitems(ItemSource* is, uchar* data, int datalen) fprint(2, " not inside
\n"); continue; } - is->curform->fields = field = newformfield( + field = newformfield( atabval(tok, Atype, input_tab, NINPUTTAB, Ftext), ++is->curform->nfields, is->curform, @@ -1115,7 +1156,7 @@ getitems(ItemSource* is, uchar* data, int datalen) aval(tok, Avalue), auintval(tok, Asize, 0), auintval(tok, Amaxlength, 1000), - is->curform->fields); + nil); if(aflagval(tok, Achecked)) field->flags = FFchecked; @@ -1167,9 +1208,6 @@ getitems(ItemSource* is, uchar* data, int datalen) atabval(tok, Aalign, align_tab, NALIGNTAB, ALbottom), auintval(tok, Awidth, 0), auintval(tok, Aheight, 0), 0, 0, 0, 0, nil); - ii = (Iimage*)field->image; - ii->nextimage = di->images; - di->images = ii; break; case Freset: @@ -1202,15 +1240,13 @@ getitems(ItemSource* is, uchar* data, int datalen) di->forms); di->forms = frm; ff = newformfield(Ftext, - 1, + ++frm->nfields, frm, _Strdup(L"_ISINDEX_"), nil, 50, 1000, nil); - frm->fields = ff; - frm->nfields = 1; additem(ps, newiformfield(ff), tok); addbrk(ps, 1, 0); break; @@ -1407,15 +1443,14 @@ getitems(ItemSource* is, uchar* data, int datalen) fprint(2, "\n"); continue; } - field = is->curform->fields; + field = is->curfield; if(field->ftype != Fselect) continue; // put options back in input order field->options = (Option*)_revlist((List*)field->options); + is->curfield = nil; break; // @@ -1553,8 +1589,6 @@ getitems(ItemSource* is, uchar* data, int datalen) } else is->tabstk = is->tabstk->next; - curtab->next = di->tables; - di->tables = curtab; curtab = is->tabstk; if(!isempty) addbrk(ps, 0, 0); @@ -1649,8 +1683,7 @@ getitems(ItemSource* is, uchar* data, int datalen) nil, 0, 0, - is->curform->fields); - is->curform->fields = field; + nil); field->rows = auintval(tok, Arows, 3); field->cols = auintval(tok, Acols, 50); field->value = getpcdata(toks, tokslen, &toki); @@ -1803,8 +1836,6 @@ getitems(ItemSource* is, uchar* data, int datalen) } if(is->tabstk != nil) is->tabstk = is->tabstk->next; - curtab->next = di->tables; - di->tables = curtab; curtab = is->tabstk; } outerps = lastps(ps); @@ -1828,6 +1859,7 @@ return_ans: else printitems(ans, "getitems returning:"); } + linkitems(di, ans); _freetokens(toks, tokslen); return ans; } @@ -3738,7 +3770,6 @@ newtable(int tableid, Align align, Dimen width, int border, t->caption_place = ALbottom; t->caption_lay = nil; t->tabletok = tok; - t->tabletok = nil; t->next = link; return t; }