commit f455686b77e4ac686251c6edf1f4a506a369866c Author: Nick Mathewson nickm@torproject.org Date: Wed Jun 12 12:04:33 2013 -0400

Unmap the microdescriptor cache before replacing it.

This is a reprise of the fix in bdff7e3299d78; 6905c1f6 reintroduced that bug. Briefly: windows doesn't seem to like deleting a mapped file. I tried adding the PROT_SHARED_DELETE flag to the createfile all, but that didn't actually fix this issue. Fortunately, the unit test I added in 4f4fc63fea0589a4fa03f3859dc27860cdde75af should prevent us from making this particular screw-up again.

This patch also tries to limit the crash potential of a failure to write by a little bit, although it could do a better job of retaining microdescriptor bodies.

Fix for bug 8822, bugfix on 0.2.4.12-alpha. --- changes/bug8822 | 5 +++++ src/or/microdesc.c | 20 +++++++++++++++++--- 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/changes/bug8822 b/changes/bug8822 new file mode 100644 index 0000000..c6787af --- /dev/null +++ b/changes/bug8822 @@ -0,0 +1,5 @@ + o Major bugfixes (windows): + - Prevent failures on Windows Vista and later when rebuilding the + microdescriptor cache. Diagnosed by Robert Ransom. Fixes bug 8822; + bugfix on 0.2.4.12-alpha. + diff --git a/src/or/microdesc.c b/src/or/microdesc.c index d9955c7..f99e1c8 100644 --- a/src/or/microdesc.c +++ b/src/or/microdesc.c @@ -474,15 +474,29 @@ microdesc_cache_rebuild(microdesc_cache_t *cache, int force) smartlist_add(wrote, md); }

+ /* We must do this unmap _before_ we call finish_writing_to_file(), or + * windows will not actually replace the file. */ + if (cache->cache_content) + tor_munmap_file(cache->cache_content); + if (finish_writing_to_file(open_file) < 0) { log_warn(LD_DIR, "Error rebuilding microdescriptor cache: %s", strerror(errno)); + /* Okay. Let's prevent from making things worse elsewhere. */ + cache->cache_content = NULL; + HT_FOREACH(mdp, microdesc_map, &cache->map) { + microdesc_t *md = *mdp; + if (md->saved_location == SAVED_IN_CACHE) { + md->off = 0; + md->saved_location = SAVED_NOWHERE; + md->body = NULL; + md->bodylen = 0; + md->no_save = 1; + } + } return -1; }

- if (cache->cache_content) - tor_munmap_file(cache->cache_content); - cache->cache_content = tor_mmap_file(cache->cache_fname);

if (!cache->cache_content && smartlist_len(wrote)) {