twinunlock bug - plan9port - [fork] Plan 9 from user space
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---
DIR commit 725d9fd7952a63c09f50d5544d0b306177462d43
DIR parent 34e8254fb8cc206664fc9dcba3c7c8ae1de6ab85
HTML Author: rsc <devnull@localhost>
Date: Thu, 28 Jul 2005 04:47:00 +0000
winunlock bug
Diffstat:
M src/cmd/acme/wind.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
---
DIR diff --git a/src/cmd/acme/wind.c b/src/cmd/acme/wind.c
t@@ -145,7 +145,6 @@ winlock(Window *w, int owner)
int i;
File *f;
-//fprint(2, "winlock %p %d %lux\n", w, owner, getcallerpc(&w));
f = w->body.file;
for(i=0; i<f->ntext; i++)
winlock1(f->text[i]->w, owner);
t@@ -157,16 +156,17 @@ winunlock(Window *w)
int i;
File *f;
-//fprint(2, "winunlock %p %lux\n", w, getcallerpc(&w));
+ /*
+ * subtle: loop runs backwards to avoid tripping over
+ * winclose indirectly editing f->text and freeing f
+ * on the last iteration of the loop.
+ */
f = w->body.file;
- for(i=0; i<f->ntext; i++){
+ for(i=f->ntext-1; i>=0; i--){
w = f->text[i]->w;
w->owner = 0;
qunlock(&w->lk);
winclose(w);
- /* winclose() can change up f->text; beware */
- if(f->ntext>0 && w != f->text[i]->w)
- --i; /* winclose() deleted window */
}
}