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-rw-r--r--changes/bug80317
-rw-r--r--src/or/microdesc.c66
2 files changed, 49 insertions, 24 deletions
diff --git a/changes/bug8031 b/changes/bug8031
new file mode 100644
index 000000000..17329ec5b
--- /dev/null
+++ b/changes/bug8031
@@ -0,0 +1,7 @@
+ o Minor bugfixes:
+ - Use direct writes rather than stdio when building microdescriptor
+ caches, in an attempt to mitigate bug 8031, or at least make it
+ less common.
+ - Warn more aggressively when flushing microdescriptors to a
+ microdescriptor cache fails, in an attempt to mitegate bug 8031,
+ or at least make it more diagnosable.
diff --git a/src/or/microdesc.c b/src/or/microdesc.c
index ac48930fa..f9dbcac80 100644
--- a/src/or/microdesc.c
+++ b/src/or/microdesc.c
@@ -71,7 +71,7 @@ HT_GENERATE(microdesc_map, microdesc_t, node,
* *<b>annotation_len_out</b> to the number of bytes written as
* annotations. */
static ssize_t
-dump_microdescriptor(FILE *f, microdesc_t *md, size_t *annotation_len_out)
+dump_microdescriptor(int fd, microdesc_t *md, size_t *annotation_len_out)
{
ssize_t r = 0;
size_t written;
@@ -81,10 +81,10 @@ dump_microdescriptor(FILE *f, microdesc_t *md, size_t *annotation_len_out)
char annotation[ISO_TIME_LEN+32];
format_iso_time(buf, md->last_listed);
tor_snprintf(annotation, sizeof(annotation), "@last-listed %s\n", buf);
- if (fputs(annotation, f) < 0) {
+ if (write_all(fd, annotation, strlen(annotation), 0) < 0) {
log_warn(LD_DIR,
"Couldn't write microdescriptor annotation: %s",
- strerror(ferror(f)));
+ strerror(errno));
return -1;
}
r += strlen(annotation);
@@ -93,13 +93,13 @@ dump_microdescriptor(FILE *f, microdesc_t *md, size_t *annotation_len_out)
*annotation_len_out = 0;
}
- md->off = (off_t) ftell(f);
- written = fwrite(md->body, 1, md->bodylen, f);
+ md->off = tor_fd_getpos(fd);
+ written = write_all(fd, md->body, md->bodylen, 0);
if (written != md->bodylen) {
log_warn(LD_DIR,
"Couldn't dump microdescriptor (wrote %lu out of %lu): %s",
(unsigned long)written, (unsigned long)md->bodylen,
- strerror(ferror(f)));
+ strerror(errno));
return -1;
}
r += md->bodylen;
@@ -198,15 +198,15 @@ microdescs_add_list_to_cache(microdesc_cache_t *cache,
{
smartlist_t *added;
open_file_t *open_file = NULL;
- FILE *f = NULL;
+ int fd = -1;
// int n_added = 0;
ssize_t size = 0;
if (where == SAVED_NOWHERE && !no_save) {
- f = start_writing_to_stdio_file(cache->journal_fname,
- OPEN_FLAGS_APPEND|O_BINARY,
- 0600, &open_file);
- if (!f) {
+ fd = start_writing_to_file(cache->journal_fname,
+ OPEN_FLAGS_APPEND|O_BINARY,
+ 0600, &open_file);
+ if (fd < 0) {
log_warn(LD_DIR, "Couldn't append to journal in %s: %s",
cache->journal_fname, strerror(errno));
return NULL;
@@ -228,9 +228,9 @@ microdescs_add_list_to_cache(microdesc_cache_t *cache,
}
/* Okay, it's a new one. */
- if (f) {
+ if (fd >= 0) {
size_t annotation_len;
- size = dump_microdescriptor(f, md, &annotation_len);
+ size = dump_microdescriptor(fd, md, &annotation_len);
if (size < 0) {
/* we already warned in dump_microdescriptor */
abort_writing_to_file(open_file);
@@ -252,8 +252,14 @@ microdescs_add_list_to_cache(microdesc_cache_t *cache,
cache->total_len_seen += md->bodylen;
} SMARTLIST_FOREACH_END(md);
- if (f)
- finish_writing_to_file(open_file); /*XXX Check me.*/
+ if (fd >= 0) {
+ if (finish_writing_to_file(open_file) < 0) {
+ log_warn(LD_DIR, "Error appending to microdescriptor file: %s",
+ strerror(errno));
+ smartlist_clear(added);
+ return added;
+ }
+ }
{
networkstatus_t *ns = networkstatus_get_latest_consensus();
@@ -406,11 +412,11 @@ int
microdesc_cache_rebuild(microdesc_cache_t *cache, int force)
{
open_file_t *open_file;
- FILE *f;
+ int fd = -1;
microdesc_t **mdp;
smartlist_t *wrote;
ssize_t size;
- off_t off = 0;
+ off_t off = 0, off_real;
int orig_size, new_size;
if (cache == NULL) {
@@ -430,10 +436,10 @@ microdesc_cache_rebuild(microdesc_cache_t *cache, int force)
orig_size = (int)(cache->cache_content ? cache->cache_content->size : 0);
orig_size += (int)cache->journal_len;
- f = start_writing_to_stdio_file(cache->cache_fname,
- OPEN_FLAGS_REPLACE|O_BINARY,
- 0600, &open_file);
- if (!f)
+ fd = start_writing_to_file(cache->cache_fname,
+ OPEN_FLAGS_REPLACE|O_BINARY,
+ 0600, &open_file);
+ if (fd < 0)
return -1;
wrote = smartlist_new();
@@ -444,7 +450,7 @@ microdesc_cache_rebuild(microdesc_cache_t *cache, int force)
if (md->no_save)
continue;
- size = dump_microdescriptor(f, md, &annotation_len);
+ size = dump_microdescriptor(fd, md, &annotation_len);
if (size < 0) {
/* XXX handle errors from dump_microdescriptor() */
/* log? return -1? die? coredump the universe? */
@@ -453,6 +459,14 @@ microdesc_cache_rebuild(microdesc_cache_t *cache, int force)
tor_assert(((size_t)size) == annotation_len + md->bodylen);
md->off = off + annotation_len;
off += size;
+ off_real = tor_fd_getpos(fd);
+ if (off_real != off) {
+ log_warn(LD_BUG, "Discontinuity in position in microdescriptor cache."
+ "By my count, I'm at "I64_FORMAT
+ ", but I should be at "I64_FORMAT,
+ I64_PRINTF_ARG(off), I64_PRINTF_ARG(off_real));
+ off = off_real;
+ }
if (md->saved_location != SAVED_IN_CACHE) {
tor_free(md->body);
md->saved_location = SAVED_IN_CACHE;
@@ -460,11 +474,15 @@ microdesc_cache_rebuild(microdesc_cache_t *cache, int force)
smartlist_add(wrote, md);
}
+ if (finish_writing_to_file(open_file) < 0) {
+ log_warn(LD_DIR, "Error rebuilding microdescriptor cache: %s",
+ strerror(errno));
+ return -1;
+ }
+
if (cache->cache_content)
tor_munmap_file(cache->cache_content);
- finish_writing_to_file(open_file); /*XXX Check me.*/
-
cache->cache_content = tor_mmap_file(cache->cache_fname);
if (!cache->cache_content && smartlist_len(wrote)) {