On 8/20/07, Xavier
On Sun, Jul 22, 2007 at 11:06:44PM +0200, Xavier wrote:
Also, if no Cache Dirs is set, pacman will try to fallback to /tmp/ , but then it segfaults. (try pacman -Sw bar).
Apparently it segfaults on this in libalpm/sync.c , sync_commit function, after downloading the file succesfully : 718 for(i = handle->dbs_sync; i; i = i->next)
I found it weird that inside that loop, i was used a second time in an inner loop : 758 for(i = alpm_option_get_cachedirs(); i; i = alpm_list_next(i)) {
I thought that was the problem, but it didn't fix the segfault.
Second strange thing is that the files list seem to be freed in any cases : 795 FREELIST(files);
but it's used at the end of that _alpm_sync_commit function : 1018 if(!validcache && !(trans->flags & PM_TRANS_FLAG_DOWNLOADONLY)) { 1019 /* delete packages */ 1020 for(i = files; i; i = i->next) { 1021 unlink(i->data); 1022 } 1023 }
Finally, if the cache isn't valid (so it fallbacks to /tmp/) and DOWNLOADONLY is used, files won't be deleted, but will they be used next times? Because the fallback (lines 779-790) happen after the check of existence of the package in the cache (lines 740-744). I can't check what happens because of the segfault.
The segfault still happened because this loop is there twice, but I only saw one occurence of it : for(i = alpm_option_get_cachedirs(); i; i = alpm_list_next(i)) {
And both times, it overlaps with the main loop. I guess Dan was tired when he wrote this ;)
I just fixed all this up in my tree today.
Anyway, I've been looking back at this code because of bug 6404 : http://bugs.archlinux.org/task/6404#comment17750
I've two questions :
1) is it very important to delete the packages when they are put in /tmp ? (the current code doing that is totally bogus as pointed out above, but I wonder if I couldn't just remove it instead of fixing it)
2) If I want to factor the "looking for package in cache" and "get a valide cache dir" codes, where would such functions belong ? I put them in libalpm/server.c , is this ok ?
Take a look at my tree. I made the decision on number 1 not to delete, and for number 2, I put them in util.c. -Dan