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Extract the body-copying portion of microdesc parsing

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This code is logically independent of the rest of the function, and
goes better in its own function.

This is almost purely code movement; I suggest reviewing with
--color-moved.
This commit is contained in:
Nick Mathewson 2019-09-09 15:21:01 -04:00
parent e7d7e04155
commit 9cbc166ea0
1 changed files with 43 additions and 16 deletions
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59
src/feature/dirparse/microdesc_parse.c
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@ -123,6 +123,45 @@ saved_location_to_string(saved_location_t where)
return location;
}
/**
* Given a microdescriptor stored in <b>where</b> which starts at <b>s</b>,
* which ends at <b>start_of_next_microdescriptor</b>, and which is located
* within a larger document beginning at <b>start</b>: Fill in the body,
* bodylen, bodylen, saved_location, off, and digest fields of <b>md</b> as
* appropriate.
*
* The body field will be an alias within <b>s</b> if <b>saved_location</b>
* is SAVED_IN_CACHE, and will be copied into body and nul-terminated
* otherwise.
**/
static int
microdesc_extract_body(microdesc_t *md,
const char *start,
const char *s, const char *start_of_next_microdesc,
saved_location_t where)
{
const int copy_body = (where != SAVED_IN_CACHE);
const char *cp = tor_memstr(s, start_of_next_microdesc-s,
"onion-key");
const int no_onion_key = (cp == NULL);
if (no_onion_key) {
cp = s; /* So that we have *some* junk to put in the body */
}
md->bodylen = start_of_next_microdesc - cp;
md->saved_location = where;
if (copy_body)
md->body = tor_memdup_nulterm(cp, md->bodylen);
else
md->body = (char*)cp;
md->off = cp - start;
crypto_digest256(md->digest, md->body, md->bodylen, DIGEST_SHA256);
return no_onion_key ? -1 : 0;
}
/** Parse as many microdescriptors as are found from the string starting at
* <b>s</b> and ending at <b>eos</b>. If allow_annotations is set, read any
* annotations we recognize and ignore ones we don't.
@ -147,7 +186,6 @@ microdescs_parse_from_string(const char *s, const char *eos,
const char *start = s;
const char *start_of_next_microdesc;
int flags = allow_annotations ? TS_ANNOTATIONS_OK : 0;
const int copy_body = (where != SAVED_IN_CACHE);
directory_token_t *tok;
@ -169,23 +207,12 @@ microdescs_parse_from_string(const char *s, const char *eos,
md = tor_malloc_zero(sizeof(microdesc_t));
uint8_t md_digest[DIGEST256_LEN];
{
const char *cp = tor_memstr(s, start_of_next_microdesc-s,
"onion-key");
const int no_onion_key = (cp == NULL);
if (no_onion_key) {
cp = s; /* So that we have *some* junk to put in the body */
}
int body_not_found = microdesc_extract_body(md, start, s,
start_of_next_microdesc,
where) < 0;
md->bodylen = start_of_next_microdesc - cp;
md->saved_location = where;
if (copy_body)
md->body = tor_memdup_nulterm(cp, md->bodylen);
else
md->body = (char*)cp;
md->off = cp - start;
crypto_digest256(md->digest, md->body, md->bodylen, DIGEST_SHA256);
memcpy(md_digest, md->digest, DIGEST256_LEN);
if (no_onion_key) {
if (body_not_found) {
log_fn(LOG_PROTOCOL_WARN, LD_DIR, "Malformed or truncated descriptor");
goto next;
}