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netsurf/content/llcache.c
Daniel Silverstone 8469f4cc8e Reimplement handling of BAD_AUTH inside browser_window 
We now handle authentication requests via an `about:` page
which presents a nice form built into the browser window.
In order to do this, we add internal navigation as a concept
to the browser window and we strip the 401login support from all
frontends except monkey.

The 401login callback is now intended for password safe type support
rather than an immediately interactive prompt.

Signed-off-by: Daniel Silverstone <dsilvers@digital-scurf.org>
2019-08-06 11:26:47 +01:00

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/*
* Copyright 2009 John-Mark Bell <jmb@netsurf-browser.org>
*
* This file is part of NetSurf, http://www.netsurf-browser.org/
*
* NetSurf is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* NetSurf is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* \file
*
* Low-level resource cache implementation
*
* This is the implementation of the low level cache. This cache
* stores source objects in memory and may use a persistent backing
* store to extend their lifetime.
*
* \todo fix writeout conditions and ordering.
*
* \todo instrument and (auto)tune
*
*/
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <strings.h>
#include <nsutils/time.h>
#include "netsurf/inttypes.h"
#include "utils/config.h"
#include "utils/corestrings.h"
#include "utils/log.h"
#include "utils/messages.h"
#include "utils/nsurl.h"
#include "utils/utils.h"
#include "utils/time.h"
#include "utils/http.h"
#include "netsurf/misc.h"
#include "desktop/gui_internal.h"
#include "content/fetch.h"
#include "content/backing_store.h"
#include "content/urldb.h"
/**
* State of a low-level cache object fetch.
*/
typedef enum {
LLCACHE_FETCH_INIT, /**< Initial state, before fetch */
LLCACHE_FETCH_HEADERS, /**< Fetching headers */
LLCACHE_FETCH_DATA, /**< Fetching object data */
LLCACHE_FETCH_COMPLETE /**< Fetch completed */
} llcache_fetch_state;
/**
* Type of low-level cache object.
*/
typedef struct llcache_object llcache_object;
/**
* Handle to low-level cache object.
*/
struct llcache_handle {
llcache_object *object; /**< Pointer to associated object */
llcache_handle_callback cb; /**< Client callback */
void *pw; /**< Client data */
llcache_fetch_state state; /**< Last known state of object fetch */
size_t bytes; /**< Last reported byte count */
};
/**
* Low-level cache object user record.
*/
typedef struct llcache_object_user {
llcache_handle *handle; /**< Handle data for client */
bool iterator_target; /**< This is the iterator target */
bool queued_for_delete; /**< This user is queued for deletion */
struct llcache_object_user *prev; /**< Previous in list */
struct llcache_object_user *next; /**< Next in list */
} llcache_object_user;
/**
* Low-level cache object fetch context.
*/
typedef struct {
uint32_t flags; /**< Fetch flags */
nsurl *referer; /**< Referring URL, or NULL if none */
llcache_post_data *post; /**< POST data, or NULL for GET */
struct fetch *fetch; /**< Fetch handle for this object */
llcache_fetch_state state; /**< Current state of object fetch */
uint32_t redirect_count; /**< Count of redirects followed */
uint32_t retries_remaining; /**< Number of times to retry on timeout */
bool hsts_in_use; /**< Whether HSTS applies to this fetch */
bool tried_with_auth; /**< Whether we've tried with auth */
bool tried_with_tls_downgrade; /**< Whether we've tried TLS <= 1.0 */
bool tainted_tls; /**< Whether the TLS transport is tainted */
} llcache_fetch_ctx;
/**
* Validation control.
*/
typedef enum {
LLCACHE_VALIDATE_FRESH, /**< Only revalidate if not fresh */
LLCACHE_VALIDATE_ALWAYS, /**< Always revalidate */
LLCACHE_VALIDATE_ONCE /**< Revalidate once only */
} llcache_validate;
/**
* Cache control value for invalid age.
*/
#define INVALID_AGE -1
/** Cache control data */
typedef struct {
time_t req_time; /**< Time of request */
time_t res_time; /**< Time of response */
time_t fin_time; /**< Time of request completion */
time_t date; /**< Date: response header */
time_t expires; /**< Expires: response header */
int age; /**< Age: response header */
int max_age; /**< Max-Age Cache-control parameter */
llcache_validate no_cache; /**< No-Cache Cache-control parameter */
char *etag; /**< Etag: response header */
time_t last_modified; /**< Last-Modified: response header */
} llcache_cache_control;
/** Representation of a fetch header */
typedef struct {
char *name; /**< Header name */
char *value; /**< Header value */
} llcache_header;
/** Current status of an object's data */
typedef enum {
LLCACHE_STATE_RAM = 0, /**< source data is stored in RAM only */
LLCACHE_STATE_DISC, /**< source data is stored on disc */
} llcache_store_state;
/**
* Low-level cache object
*
* \todo Consider whether a list is a sane container.
*/
struct llcache_object {
llcache_object *prev; /**< Previous in list */
llcache_object *next; /**< Next in list */
nsurl *url; /**< Post-redirect URL for object */
/** \todo We need a generic dynamic buffer object */
uint8_t *source_data; /**< Source data for object */
size_t source_len; /**< Byte length of source data */
size_t source_alloc; /**< Allocated size of source buffer */
llcache_store_state store_state; /**< where the data for the object is stored */
llcache_object_user *users; /**< List of users */
llcache_fetch_ctx fetch; /**< Fetch context for object */
llcache_cache_control cache; /**< Cache control data for object */
llcache_object *candidate; /**< Object to use, if fetch determines
* that it is still fresh
*/
uint32_t candidate_count; /**< Count of objects this is a
* candidate for
*/
llcache_header *headers; /**< Fetch headers */
size_t num_headers; /**< Number of fetch headers */
/* Instrumentation. These elements are strictly for information
* to improve the cache performance and to provide performance
* metrics. The values are non-authoritative and must not be used to
* determine object lifetime etc.
*/
time_t last_used; /**< time the last user was removed from the object */
};
/**
* Core llcache control context.
*/
struct llcache_s {
/** Head of the low-level cached object list */
llcache_object *cached_objects;
/** Head of the low-level uncached object list */
llcache_object *uncached_objects;
/** The target upper bound for the RAM cache size */
uint32_t limit;
/** The number of fetch attempts we make when timing out */
uint32_t fetch_attempts;
/** Whether or not our users are caught up */
bool all_caught_up;
/* backing store elements */
/**
* The minimum lifetime to consider sending objects to backing
* store.
*/
int minimum_lifetime;
/**
* The time over which to apply the bandwidth calculations in ms
*/
unsigned long time_quantum;
/**
* The minimum bandwidth to allow the backing store to use in
* bytes/second. Below this the backing store will be
* disabled.
*/
size_t minimum_bandwidth;
/**
* The maximum bandwidth to allow the backing store to use in
* bytes/second
*/
size_t maximum_bandwidth;
/**
* Total number of bytes written to backing store.
*/
uint64_t total_written;
/**
* Total number of milliseconds taken to write to backing store.
*/
uint64_t total_elapsed;
};
/** low level cache state */
static struct llcache_s *llcache = NULL;
/* forward referenced callback function */
static void llcache_fetch_callback(const fetch_msg *msg, void *p);
/* forward referenced catch up function */
static void llcache_users_not_caught_up(void);
/******************************************************************************
* Low-level cache internals *
******************************************************************************/
/**
* Create a new object user.
*
* \param cb Callback routine.
* \param pw Private data for callback.
* \param user Pointer to location to receive result.
* \return NSERROR_OK on success, appropriate error otherwise
*/
static nserror llcache_object_user_new(llcache_handle_callback cb, void *pw,
llcache_object_user **user)
{
llcache_handle *h;
llcache_object_user *u;
h = calloc(1, sizeof(llcache_handle));
if (h == NULL) {
return NSERROR_NOMEM;
}
u = calloc(1, sizeof(llcache_object_user));
if (u == NULL) {
free(h);
return NSERROR_NOMEM;
}
h->cb = cb;
h->pw = pw;
u->handle = h;
NSLOG(llcache, DEBUG,
"Created user %p (%p, %p, %p)", u, h, (void *) cb, pw);
*user = u;
return NSERROR_OK;
}
/**
* Destroy an object user
*
* \param user User to destroy
* \return NSERROR_OK on success, appropriate error otherwise
*
* \pre User is not attached to an object
*/
static nserror llcache_object_user_destroy(llcache_object_user *user)
{
NSLOG(llcache, DEBUG, "Destroyed user %p", user);
assert(user->next == NULL);
assert(user->prev == NULL);
if (user->handle != NULL)
free(user->handle);
free(user);
return NSERROR_OK;
}
/**
* Remove a user from a low-level cache object
*
* \param object Object to remove user from
* \param user User to remove
* \return NSERROR_OK.
*/
static nserror llcache_object_remove_user(llcache_object *object,
llcache_object_user *user)
{
assert(user != NULL);
assert(object != NULL);
assert(object->users != NULL);
assert(user->handle == NULL || user->handle->object == object);
assert((user->prev != NULL) || (object->users == user));
if (user == object->users)
object->users = user->next;
else
user->prev->next = user->next;
if (user->next != NULL)
user->next->prev = user->prev;
user->next = user->prev = NULL;
/* record the time the last user was removed from the object */
if (object->users == NULL) {
object->last_used = time(NULL);
}
NSLOG(llcache, DEBUG, "Removing user %p from %p", user, object);
return NSERROR_OK;
}
/**
* Iterate the users of an object, calling their callbacks.
*
* \param object The object to iterate
* \param event The event to pass to the callback.
* \return NSERROR_OK on success, appropriate error otherwise.
*/
static nserror llcache_send_event_to_users(llcache_object *object,
llcache_event *event)
{
nserror error = NSERROR_OK;
llcache_object_user *user, *next_user;
user = object->users;
while (user != NULL) {
bool was_target = user->iterator_target;
user->iterator_target = true;
error = user->handle->cb(user->handle, event,
user->handle->pw);
next_user = user->next;
user->iterator_target = was_target;
if (user->queued_for_delete && !was_target) {
llcache_object_remove_user(object, user);
llcache_object_user_destroy(user);
}
if (error != NSERROR_OK)
break;
user = next_user;
}
return error;
}
/**
* Create a new low-level cache object
*
* \param url URL of object to create
* \param result Pointer to location to receive result
* \return NSERROR_OK on success, appropriate error otherwise
*/
static nserror llcache_object_new(nsurl *url, llcache_object **result)
{
llcache_object *obj = calloc(1, sizeof(llcache_object));
if (obj == NULL)
return NSERROR_NOMEM;
NSLOG(llcache, DEBUG, "Created object %p (%s)", obj, nsurl_access(url));
obj->url = nsurl_ref(url);
*result = obj;
return NSERROR_OK;
}
/**
* Clone a POST data object
*
* \param orig Object to clone
* \param clone Pointer to location to receive clone
* \return NSERROR_OK on success, appropriate error otherwise
*/
static nserror llcache_post_data_clone(const llcache_post_data *orig,
llcache_post_data **clone)
{
llcache_post_data *post_clone;
post_clone = calloc(1, sizeof(llcache_post_data));
if (post_clone == NULL)
return NSERROR_NOMEM;
post_clone->type = orig->type;
/* Deep-copy the type-specific data */
if (orig->type == LLCACHE_POST_URL_ENCODED) {
post_clone->data.urlenc = strdup(orig->data.urlenc);
if (post_clone->data.urlenc == NULL) {
free(post_clone);
return NSERROR_NOMEM;
}
} else {
post_clone->data.multipart = fetch_multipart_data_clone(
orig->data.multipart);
if (post_clone->data.multipart == NULL) {
free(post_clone);
return NSERROR_NOMEM;
}
}
*clone = post_clone;
return NSERROR_OK;
}
/**
* Split a fetch header into name and value
*
* HTTP header splitting according to grammar defined in RFC7230 section 3.2
* https://tools.ietf.org/html/rfc7230#section-3.2
*
* This implementation is non conformant in that it:
* - includes carrige return and newline in whitespace (3.2.3)
* - allows whitespace before and after the field-name token (3.2.4)
* - does not handle obsolete line folding (3.2.4)
*
* \param data Header string
* \param len Byte length of header
* \param name Pointer to location to receive header name
* \param value Pointer to location to receive header value
* \return NSERROR_OK on success, appropriate error otherwise
*/
static nserror llcache_fetch_split_header(const uint8_t *data, size_t len,
char **name, char **value)
{
char *n, *v;
const uint8_t *colon;
/* Strip leading whitespace from name */
while (data[0] == ' ' || data[0] == '\t' ||
data[0] == '\r' || data[0] == '\n') {
data++;
}
/* Find colon */
colon = (const uint8_t *) strchr((const char *) data, ':');
if (colon == NULL) {
/* Failed, assume a key with no value */
colon = data + strlen((const char *)data);
/* Strip trailing whitespace from name */
while ((colon > data) &&
(colon[-1] == ' ' || colon[-1] == '\t' ||
colon[-1] == '\r' || colon[-1] == '\n')) {
colon--;
}
n = strndup((const char *) data, colon - data);
if (n == NULL)
return NSERROR_NOMEM;
v = strdup("");
if (v == NULL) {
free(n);
return NSERROR_NOMEM;
}
} else {
/* Split header into name & value */
/* Strip trailing whitespace from name */
while (colon > data && (colon[-1] == ' ' ||
colon[-1] == '\t' || colon[-1] == '\r' ||
colon[-1] == '\n'))
colon--;
n = strndup((const char *) data, colon - data);
if (n == NULL)
return NSERROR_NOMEM;
/* Find colon again */
while (*colon != ':') {
colon++;
}
/* Skip over colon and any subsequent whitespace */
do {
colon++;
} while (*colon == ' ' || *colon == '\t' ||
*colon == '\r' || *colon == '\n');
/* Strip trailing whitespace from value */
while (len > 0 && (data[len - 1] == ' ' ||
data[len - 1] == '\t' ||
data[len - 1] == '\r' ||
data[len - 1] == '\n')) {
len--;
}
v = strndup((const char *) colon, len - (colon - data));
if (v == NULL) {
free(n);
return NSERROR_NOMEM;
}
}
*name = n;
*value = v;
return NSERROR_OK;
}
/**
* parse cache control header value
*
* \param object Object to parse header for
* \param value header value
* \return NSERROR_OK on success, appropriate error otherwise
*/
static nserror
llcache_fetch_parse_cache_control(llcache_object *object, char *value)
{
http_cache_control *cc;
nserror error;
error = http_parse_cache_control(value, &cc);
if (error != NSERROR_OK) {
/* Ignore parse errors */
return NSERROR_OK;
}
if (http_cache_control_no_cache(cc) ||
http_cache_control_no_store(cc)) {
/**
* \todo When we get a disk cache we should
* distinguish between these two.
*/
object->cache.no_cache = LLCACHE_VALIDATE_ALWAYS;
}
if (http_cache_control_has_max_age(cc)) {
object->cache.max_age = http_cache_control_max_age(cc);
}
http_cache_control_destroy(cc);
return NSERROR_OK;
}
/**
* Update cache control from appropriate header
*
* \param object Object to parse header for
* \param name header name
* \param value header value
* \return NSERROR_OK on success, appropriate error otherwise
*/
static nserror
llcache_fetch_header_cache_control(llcache_object *object,
char *name,
char *value)
{
nserror res;
size_t name_len;
/* Parse cache headers to populate cache control data */
name_len = strlen(name);
switch (name_len) {
case 3:
if (strcasecmp(name, "Age") == 0) {
/* extract Age header */
if ('0' <= *value && *value <= '9') {
object->cache.age = atoi(value);
}
}
break;
case 4:
if (strcasecmp(name, "Date") == 0) {
/* extract Date header */
res = nsc_strntimet(value,
strlen(value),
&object->cache.date);
if (res != NSERROR_OK) {
NSLOG(llcache, INFO,
"Processing Date header value \"%s\" returned %d",
value, res);
}
} else if (strcasecmp(name, "ETag") == 0) {
/* extract ETag header */
free(object->cache.etag);
object->cache.etag = strdup(value);
if (object->cache.etag == NULL) {
NSLOG(llcache, INFO,
"No memory to duplicate ETag");
return NSERROR_NOMEM;
}
}
break;
case 7:
if (strcasecmp(name, "Expires") == 0) {
/* process Expires header value */
res = nsc_strntimet(value,
strlen(value),
&object->cache.expires);
if (res != NSERROR_OK) {
NSLOG(llcache, INFO,
"Processing Expires header value \"%s\" returned %d",
value, res);
object->cache.expires = (time_t)0x7fffffff;
}
}
break;
case 13:
if (strcasecmp(name, "Cache-Control") == 0) {
/* parse Cache-Control header value */
llcache_fetch_parse_cache_control(object,value);
} else if (strcasecmp(name, "Last-Modified") == 0) {
/* parse Last-Modified header value */
nsc_strntimet(value,
strlen(value),
&object->cache.last_modified);
}
break;
}
return NSERROR_OK;
}
/**
* Destroy headers.
*
* \param object The object to destroy headers within.
*/
static inline void llcache_destroy_headers(llcache_object *object)
{
while (object->num_headers > 0) {
object->num_headers--;
free(object->headers[object->num_headers].name);
free(object->headers[object->num_headers].value);
}
free(object->headers);
object->headers = NULL;
}
/**
* Invalidate cache control data.
*
* \param object The object to invalidate cache control for.
*/
static inline void llcache_invalidate_cache_control_data(llcache_object *object)
{
free(object->cache.etag);
memset(&(object->cache), 0, sizeof(llcache_cache_control));
object->cache.age = INVALID_AGE;
object->cache.max_age = INVALID_AGE;
}
/**
* Process a fetch header
*
* \param object Object being fetched
* \param data Header string
* \param len Byte length of header
* \return NSERROR_OK on success, appropriate error otherwise
*/
static nserror llcache_fetch_process_header(llcache_object *object,
const uint8_t *data, size_t len)
{
nserror res;
char *name, *value;
llcache_header *temp;
/**
* \note The headers for multiple HTTP responses may be
* delivered to us if the fetch layer receives a 401 response
* for which it has authentication credentials. This will
* result in a silent re-request after which we'll receive the
* actual response headers for the object we want to fetch
* (assuming that the credentials were correct of course)
*
* Therefore, if the header is an HTTP response start marker, then we
* must discard any headers we've read so far, reset the cache data
* that we might have computed, and start again.
*/
/** \todo Properly parse the response line */
if (strncmp((const char *) data, "HTTP/", SLEN("HTTP/")) == 0) {
time_t req_time = object->cache.req_time;
llcache_invalidate_cache_control_data(object);
/* Restore request time, so we compute object's age correctly */
object->cache.req_time = req_time;
llcache_destroy_headers(object);
}
/* Set fetch response time if not already set */
if (object->cache.res_time == 0) {
object->cache.res_time = time(NULL);
}
/* Parse header into name-value pair */
res = llcache_fetch_split_header(data, len, &name, &value);
if (res != NSERROR_OK) {
return res;
}
/* deal with empty header */
if (name[0] == 0) {
free(name);
free(value);
return NSERROR_OK;
}
/* update cache control data from header */
res = llcache_fetch_header_cache_control(object, name, value);
if (res != NSERROR_OK) {
free(name);
free(value);
return res;
}
/* Append header data to the object's headers array */
temp = realloc(object->headers,
(object->num_headers + 1) * sizeof(llcache_header));
if (temp == NULL) {
free(name);
free(value);
return NSERROR_NOMEM;
}
object->headers = temp;
object->headers[object->num_headers].name = name;
object->headers[object->num_headers].value = value;
object->num_headers++;
return NSERROR_OK;
}
/**
* (Re)fetch an object
*
* Sets up headers and attempts to start an actual fetch from the
* fetchers system updating the llcache object with the new fetch on
* successful start.
*
* \pre The fetch parameters in object->fetch must be populated
*
* \param object Object to refetch
* \return NSERROR_OK on success, appropriate error otherwise
*/
static nserror llcache_object_refetch(llcache_object *object)
{
const char *urlenc = NULL;
struct fetch_multipart_data *multipart = NULL;
char **headers = NULL;
int header_idx = 0;
nserror res;
if (object->fetch.post != NULL) {
if (object->fetch.post->type == LLCACHE_POST_URL_ENCODED) {
urlenc = object->fetch.post->data.urlenc;
} else {
multipart = object->fetch.post->data.multipart;
}
}
/* Generate cache-control headers */
headers = malloc(3 * sizeof(char *));
if (headers == NULL) {
return NSERROR_NOMEM;
}
if (object->cache.etag != NULL) {
const size_t len = SLEN("If-None-Match: ") +
strlen(object->cache.etag) + 1;
headers[header_idx] = malloc(len);
if (headers[header_idx] == NULL) {
free(headers);
return NSERROR_NOMEM;
}
snprintf(headers[header_idx], len, "If-None-Match: %s",
object->cache.etag);
header_idx++;
}
if (object->cache.last_modified != 0) {
/* Maximum length of an RFC 1123 date is 29 bytes */
const size_t len = SLEN("If-Modified-Since: ") + 29 + 1;
headers[header_idx] = malloc(len);
if (headers[header_idx] == NULL) {
while (--header_idx >= 0)
free(headers[header_idx]);
free(headers);
return NSERROR_NOMEM;
}
snprintf(headers[header_idx], len, "If-Modified-Since: %s",
rfc1123_date(object->cache.last_modified));
header_idx++;
}
headers[header_idx] = NULL;
/* Reset cache control data */
llcache_invalidate_cache_control_data(object);
object->cache.req_time = time(NULL);
object->cache.fin_time = object->cache.req_time;
/* Reset fetch state */
object->fetch.state = LLCACHE_FETCH_INIT;
NSLOG(llcache, DEBUG, "Re-fetching %p", object);
/* Kick off fetch */
res = fetch_start(object->url,
object->fetch.referer,
llcache_fetch_callback,
object,
object->fetch.flags & LLCACHE_RETRIEVE_NO_ERROR_PAGES,
urlenc,
multipart,
object->fetch.flags & LLCACHE_RETRIEVE_VERIFIABLE,
object->fetch.tried_with_tls_downgrade,
(const char **)headers,
&object->fetch.fetch);
/* Clean up cache-control headers */
while (--header_idx >= 0) {
free(headers[header_idx]);
}
free(headers);
return res;
}
/**
* Kick-off a fetch for an object
*
* \pre object::url must contain the URL to fetch
* \pre If there is a freshness validation candidate,
* object::candidate and object::cache must be filled in
* \pre There must not be a fetch in progress for \a object
*
* \param object Object to fetch
* \param flags Fetch flags
* \param referer Referring URL, or NULL for none
* \param post POST data, or NULL for GET
* \param redirect_count Number of redirects followed so far
* \param hsts_in_use Whether HSTS applies to this fetch
* \return NSERROR_OK on success, appropriate error otherwise
*/
static nserror llcache_object_fetch(llcache_object *object, uint32_t flags,
nsurl *referer, const llcache_post_data *post,
uint32_t redirect_count, bool hsts_in_use)
{
nserror error;
nsurl *referer_clone = NULL;
llcache_post_data *post_clone = NULL;
NSLOG(llcache, DEBUG, "Starting fetch for %p", object);
if (post != NULL) {
error = llcache_post_data_clone(post, &post_clone);
if (error != NSERROR_OK)
return error;
}
if (referer != NULL)
referer_clone = nsurl_ref(referer);
object->fetch.flags = flags;
object->fetch.referer = referer_clone;
object->fetch.post = post_clone;
object->fetch.redirect_count = redirect_count;
object->fetch.retries_remaining = llcache->fetch_attempts;
object->fetch.hsts_in_use = hsts_in_use;
return llcache_object_refetch(object);
}
/**
* Destroy a low-level cache object
*
* \pre Object is detached from cache list
* \pre Object has no users
* \pre Object is not a candidate (i.e. object::candidate_count == 0)
*
* \param object Object to destroy
* \return NSERROR_OK on success, appropriate error otherwise
*/
static nserror llcache_object_destroy(llcache_object *object)
{
size_t i;
NSLOG(llcache, DEBUG, "Destroying object %p, %s", object,
nsurl_access(object->url));
if (object->source_data != NULL) {
if (object->store_state == LLCACHE_STATE_DISC) {
guit->llcache->release(object->url, BACKING_STORE_NONE);
} else {
free(object->source_data);
}
}
nsurl_unref(object->url);
if (object->fetch.fetch != NULL) {
fetch_abort(object->fetch.fetch);
object->fetch.fetch = NULL;
}
if (object->fetch.referer != NULL)
nsurl_unref(object->fetch.referer);
if (object->fetch.post != NULL) {
if (object->fetch.post->type == LLCACHE_POST_URL_ENCODED) {
free(object->fetch.post->data.urlenc);
} else {
fetch_multipart_data_destroy(
object->fetch.post->data.multipart);
}
free(object->fetch.post);
}
free(object->cache.etag);
for (i = 0; i < object->num_headers; i++) {
free(object->headers[i].name);
free(object->headers[i].value);
}
free(object->headers);
free(object);
return NSERROR_OK;
}
/**
* Add a low-level cache object to a cache list
*
* \param object Object to add
* \param list List to add to
* \return NSERROR_OK
*/
static nserror llcache_object_add_to_list(llcache_object *object,
llcache_object **list)
{
object->prev = NULL;
object->next = *list;
if (*list != NULL)
(*list)->prev = object;
*list = object;
return NSERROR_OK;
}
/**
* Determine the remaining lifetime of a cache object using the
*
* \param cd cache control data.
* \return The length of time remaining for the object or 0 if expired.
*/
static int
llcache_object_rfc2616_remaining_lifetime(const llcache_cache_control *cd)
{
int current_age, freshness_lifetime;
time_t now = time(NULL);
/* Calculate staleness of cached object as per RFC 2616 13.2.3/13.2.4 */
current_age = max(0, (cd->res_time - cd->date));
current_age = max(current_age, (cd->age == INVALID_AGE) ? 0 : cd->age);
current_age += cd->res_time - cd->req_time + now - cd->res_time;
/* Determine freshness lifetime of this object */
if (cd->max_age != INVALID_AGE) {
freshness_lifetime = cd->max_age;
} else if (cd->expires != 0) {
freshness_lifetime = cd->expires - cd->date;
} else if (cd->last_modified != 0) {
freshness_lifetime = (now - cd->last_modified) / 10;
} else {
freshness_lifetime = 0;
}
NSLOG(llcache, DEBUG, "%d:%d", freshness_lifetime, current_age);
if ((cd->no_cache == LLCACHE_VALIDATE_FRESH) &&
(freshness_lifetime > current_age)) {
/* object was not forbidden from being returned from
* the cache unvalidated (i.e. the response contained
* a no-cache directive)
*
* The object current age is within the freshness lifetime.
*/
return freshness_lifetime - current_age;
}
return 0; /* object has no remaining lifetime */
}
/**
* Determine if an object is still fresh
*
* \param object Object to consider
* \return True if object is still fresh, false otherwise
*/
static bool llcache_object_is_fresh(const llcache_object *object)
{
int remaining_lifetime;
const llcache_cache_control *cd = &object->cache;
remaining_lifetime = llcache_object_rfc2616_remaining_lifetime(cd);
NSLOG(llcache, DEBUG, "%p: (%d > 0 || %d != %d)", object,
remaining_lifetime,
object->fetch.state, LLCACHE_FETCH_COMPLETE);
/* The object is fresh if:
* - it was not forbidden from being returned from the cache
* unvalidated.
*
* - it has remaining lifetime or still being fetched.
*/
return ((cd->no_cache == LLCACHE_VALIDATE_FRESH) &&
((remaining_lifetime > 0) ||
(object->fetch.state != LLCACHE_FETCH_COMPLETE)));
}
/**
* Clone an object's cache data
*
* \post If \a deep is false, then any pointers in \a source will be set to NULL
*
* \param source Source object containing cache data to clone
* \param destination Destination object to clone cache data into
* \param deep Whether to deep-copy the data or not
* \return NSERROR_OK on success, appropriate error otherwise
*/
static nserror llcache_object_clone_cache_data(llcache_object *source,
llcache_object *destination, bool deep)
{
/* ETag must be first, as it can fail when deep cloning */
if (source->cache.etag != NULL) {
char *etag = source->cache.etag;
if (deep) {
/* Copy the etag */
etag = strdup(source->cache.etag);
if (etag == NULL)
return NSERROR_NOMEM;
} else {
/* Destination takes ownership */
source->cache.etag = NULL;
}
if (destination->cache.etag != NULL)
free(destination->cache.etag);
destination->cache.etag = etag;
}
destination->cache.req_time = source->cache.req_time;
destination->cache.res_time = source->cache.res_time;
destination->cache.fin_time = source->cache.fin_time;
if (source->cache.date != 0)
destination->cache.date = source->cache.date;
if (source->cache.expires != 0)
destination->cache.expires = source->cache.expires;
if (source->cache.age != INVALID_AGE)
destination->cache.age = source->cache.age;
if (source->cache.max_age != INVALID_AGE)
destination->cache.max_age = source->cache.max_age;
if (source->cache.no_cache != LLCACHE_VALIDATE_FRESH)
destination->cache.no_cache = source->cache.no_cache;
if (source->cache.last_modified != 0)
destination->cache.last_modified = source->cache.last_modified;
return NSERROR_OK;
}
/**
* Remove a low-level cache object from a cache list
*
* \param object Object to remove
* \param list List to remove from
* \return NSERROR_OK
*/
static nserror
llcache_object_remove_from_list(llcache_object *object, llcache_object **list)
{
if (object == *list)
*list = object->next;
else
object->prev->next = object->next;
if (object->next != NULL)
object->next->prev = object->prev;
return NSERROR_OK;
}
/**
* Retrieve source data for an object from persistent store if necessary.
*
* If an object's source data has been placed in the persistent store
* and there is no in-memory copy, then attempt to retrieve the source
* data.
*
* \param object the object to operate on.
* \return appropriate error code.
*/
static nserror llcache_retrieve_persisted_data(llcache_object *object)
{
/* ensure the source data is present if necessary */
if ((object->source_data != NULL) ||
(object->store_state != LLCACHE_STATE_DISC)) {
/* source data does not require retrieving from
* persistent store.
*/
return NSERROR_OK;
}
/* Source data for the object may be in the persistent store */
return guit->llcache->fetch(object->url,
BACKING_STORE_NONE,
&object->source_data,
&object->source_len);
}
/**
* Generate a serialised version of an object's metadata
*
* The metadata includes object headers.
*
* \param object The cache object to serialise the metadata of.
* \param data_out Where the serialised buffer will be placed.
* \param datasize_out The size of the serialised data.
* \return NSERROR_OK on success with \a data_out and \a datasize_out
* updated, NSERROR_NOMEM on memory exhaustion or
* NSERROR_INVALID if there was an error serialising the
* stream.
*/
static nserror
llcache_serialise_metadata(llcache_object *object,
uint8_t **data_out,
size_t *datasize_out)
{
size_t allocsize;
int datasize;
uint8_t *data;
char *op;
unsigned int hloop;
int use;
allocsize = 10 + 1; /* object length */
allocsize += 10 + 1; /* request time */
allocsize += 10 + 1; /* response time */
allocsize += 10 + 1; /* completion time */
allocsize += 10 + 1; /* space for number of header entries */
allocsize += nsurl_length(object->url) + 1;
for (hloop = 0 ; hloop < object->num_headers ; hloop++) {
allocsize += strlen(object->headers[hloop].name) + 1;
allocsize += strlen(object->headers[hloop].value) + 1;
}
data = malloc(allocsize);
if (data == NULL) {
return NSERROR_NOMEM;
}
op = (char *)data;
datasize = allocsize;
/* the url, used for checking for collisions */
use = snprintf(op, datasize, "%s", nsurl_access(object->url));
if (use < 0) {
goto operror;
}
use++; /* does not count the null */
if (use > datasize) {
goto overflow;
}
op += use;
datasize -= use;
/* object size */
use = snprintf(op, datasize, "%" PRIsizet, object->source_len);
if (use < 0) {
goto operror;
}
use++; /* does not count the null */
if (use > datasize)
goto overflow;
op += use;
datasize -= use;
/* Time of request */
use = nsc_sntimet(op, datasize, &object->cache.req_time);
if (use == 0)
goto overflow;
use++; /* does not count the null */
op += use;
datasize -= use;
/* Time of response */
use = nsc_sntimet(op, datasize, &object->cache.res_time);
if (use == 0)
goto overflow;
use++; /* does not count the null */
op += use;
datasize -= use;
/* Time of completion */
use = nsc_sntimet(op, datasize, &object->cache.fin_time);
if (use == 0)
goto overflow;
use++; /* does not count the null */
op += use;
datasize -= use;
/* number of headers */
use = snprintf(op, datasize, "%" PRIsizet, object->num_headers);
if (use < 0) {
goto operror;
}
use++; /* does not count the null */
if (use > datasize)
goto overflow;
op += use;
datasize -= use;
/* headers */
for (hloop = 0 ; hloop < object->num_headers ; hloop++) {
use = snprintf(op, datasize,
"%s:%s",
object->headers[hloop].name,
object->headers[hloop].value);
if (use < 0) {
goto operror;
}
use++; /* does not count the null */
if (use > datasize)
goto overflow;
op += use;
datasize -= use;
}
NSLOG(llcache, DEBUG, "Filled buffer with %d spare", datasize);
*data_out = data;
*datasize_out = allocsize - datasize;
return NSERROR_OK;
overflow:
/* somehow we overflowed the buffer - hth? */
NSLOG(llcache, INFO, "Overflowed metadata buffer");
free(data);
return NSERROR_INVALID;
operror:
/* output error */
NSLOG(llcache, INFO, "Output error");
free(data);
return NSERROR_INVALID;
}
/**
* Deserialisation of an object's metadata.
*
* Attempt to retrieve and deserialise the metadata for an object from
* the backing store.
*
* This must only update object if it is successful otherwise difficult
* to debug crashes happen later by using bad leftover object state.
*
* \param object The object to retrieve the metadata for.
* \return NSERROR_OK if the metatdata was retrieved and deserialised
* or error code if URL is not in persistent storage or in
* event of deserialisation error.
*/
static nserror
llcache_process_metadata(llcache_object *object)
{
nserror res;
uint8_t *metadata = NULL;
size_t metadatalen = 0;
nsurl *metadataurl;
unsigned int line;
char *ln;
int lnsize;
size_t source_length;
time_t request_time;
time_t response_time;
time_t completion_time;
size_t num_headers;
size_t hloop;
NSLOG(llcache, INFO, "Retrieving metadata");
/* attempt to retrieve object metadata from the backing store */
res = guit->llcache->fetch(object->url,
BACKING_STORE_META,
&metadata,
&metadatalen);
if (res != NSERROR_OK) {
return res;
}
NSLOG(llcache, INFO, "Processing retrieved data");
/* metadata line 1 is the url the metadata referrs to */
line = 1;
ln = (char *)metadata;
lnsize = strlen(ln);
if (lnsize < 7) {
res = NSERROR_INVALID;
goto format_error;
}
res = nsurl_create(ln, &metadataurl);
if (res != NSERROR_OK)
goto format_error;
if (nsurl_compare(object->url, metadataurl, NSURL_COMPLETE) != true) {
/* backing store returned the wrong object for the
* request. This may occur if the backing store had
* a collision in its storage method. We cope with this
* by simply skipping caching of this object.
*/
NSLOG(llcache, INFO, "Got metadata for %s instead of %s",
nsurl_access(metadataurl), nsurl_access(object->url));
nsurl_unref(metadataurl);
guit->llcache->release(object->url, BACKING_STORE_META);
return NSERROR_BAD_URL;
}
nsurl_unref(metadataurl);
/* metadata line 2 is the object's length */
line = 2;
ln += lnsize + 1;
lnsize = strlen(ln);
if ((lnsize < 1) || (sscanf(ln, "%" PRIsizet, &source_length) != 1)) {
res = NSERROR_INVALID;
goto format_error;
}
/* metadata line 3 is the time of request */
line = 3;
ln += lnsize + 1;
lnsize = strlen(ln);
res = nsc_snptimet(ln, lnsize, &request_time);
if (res != NSERROR_OK)
goto format_error;
/* metadata line 4 is the time of response */
line = 4;
ln += lnsize + 1;
lnsize = strlen(ln);
res = nsc_snptimet(ln, lnsize, &response_time);
if (res != NSERROR_OK)
goto format_error;
/* metadata line 5 is the time of request completion */
line = 5;
ln += lnsize + 1;
lnsize = strlen(ln);
res = nsc_snptimet(ln, lnsize, &completion_time);
if (res != NSERROR_OK)
goto format_error;
/* metadata line 6 is the number of headers */
line = 6;
ln += lnsize + 1;
lnsize = strlen(ln);
if ((lnsize < 1) || (sscanf(ln, "%" PRIsizet, &num_headers) != 1)) {
res = NSERROR_INVALID;
goto format_error;
}
/* read headers */
for (hloop = 0 ; hloop < num_headers; hloop++) {
line++;
ln += lnsize + 1;
lnsize = strlen(ln);
res = llcache_fetch_process_header(object,
(uint8_t *)ln,
lnsize);
if (res != NSERROR_OK)
goto format_error;
}
guit->llcache->release(object->url, BACKING_STORE_META);
/* update object on successful parse of metadata */
object->source_len = source_length;
/** \todo really not sure this is right, nothing is allocated here? */
object->source_alloc = metadatalen;
object->cache.req_time = request_time;
object->cache.res_time = response_time;
object->cache.fin_time = completion_time;
/* object stored in backing store */
object->store_state = LLCACHE_STATE_DISC;
return NSERROR_OK;
format_error:
NSLOG(llcache, INFO,
"metadata error on line %d error code %d\n",
line, res);
guit->llcache->release(object->url, BACKING_STORE_META);
return res;
}
/**
* Attempt to retrieve an object from persistent storage.
*
* \param object The object to populate from persistent store.
* \param flags Fetch flags.
* \param referer The referring url.
* \param post Post data for fetch.
* \param redirect_count how many times this fetch has been redirected.
* \return NSERROR_OK if the object was successfully retrieved from the
* cache else appropriate error code.
*/
static nserror
llcache_object_fetch_persistent(llcache_object *object,
uint32_t flags,
nsurl *referer,
const llcache_post_data *post,
uint32_t redirect_count)
{
nserror error;
nsurl *referer_clone = NULL;
llcache_post_data *post_clone = NULL;
object->cache.req_time = time(NULL);
object->cache.fin_time = object->cache.req_time;
/* retrieve and process metadata */
error = llcache_process_metadata(object);
if (error != NSERROR_OK) {
return error;
}
/* entry came out of cache - need to setup object state */
if (post != NULL) {
error = llcache_post_data_clone(post, &post_clone);
if (error != NSERROR_OK)
return error;
}
if (referer != NULL) {
referer_clone = nsurl_ref(referer);
}
object->fetch.flags = flags;
object->fetch.referer = referer_clone;
object->fetch.post = post_clone;
object->fetch.redirect_count = redirect_count;
/* fetch is "finished" */
object->fetch.state = LLCACHE_FETCH_COMPLETE;
object->fetch.fetch = NULL;
return NSERROR_OK;
}
/**
* Retrieve a potentially cached object
*
* \param url URL of object to retrieve
* \param flags Fetch flags
* \param referer Referring URL, or NULL if none
* \param post POST data, or NULL for a GET request
* \param redirect_count Number of redirects followed so far
* \param hsts_in_use Whether HSTS applies to this fetch
* \param result Pointer to location to receive retrieved object
* \return NSERROR_OK on success, appropriate error otherwise
*/
static nserror
llcache_object_retrieve_from_cache(nsurl *url,
uint32_t flags,
nsurl *referer,
const llcache_post_data *post,
uint32_t redirect_count,
bool hsts_in_use,
llcache_object **result)
{
nserror error;
llcache_object *obj, *newest = NULL;
NSLOG(llcache, DEBUG,
"Searching cache for %s flags:%x referer:%s post:%p",
nsurl_access(url), flags,
referer==NULL?"":nsurl_access(referer),
post);
/* Search for the most recently fetched matching object */
for (obj = llcache->cached_objects; obj != NULL; obj = obj->next) {
if ((newest == NULL ||
obj->cache.req_time > newest->cache.req_time) &&
nsurl_compare(obj->url, url,
NSURL_COMPLETE) == true) {
newest = obj;
}
}
/* No viable object found in cache create one and attempt to
* pull from persistent store.
*/
if (newest == NULL) {
NSLOG(llcache, DEBUG, "No viable object found in llcache");
error = llcache_object_new(url, &obj);
if (error != NSERROR_OK)
return error;
/* attempt to retrieve object from persistent store */
error = llcache_object_fetch_persistent(obj, flags, referer, post, redirect_count);
if (error == NSERROR_OK) {
NSLOG(llcache, DEBUG, "retrieved object from persistent store");
/* set newest object from persistent store which
* will cause the normal object handling to be used.
*/
newest = obj;
/* Add new object to cached object list */
llcache_object_add_to_list(obj, &llcache->cached_objects);
}
/* else no object found and irretrievable from cache,
* fall through with newest unset to start fetch
*/
}
if ((newest != NULL) && (llcache_object_is_fresh(newest))) {
/* Found a suitable object, and it's still fresh */
NSLOG(llcache, DEBUG, "Found fresh %p", newest);
/* The client needs to catch up with the object's state.
* This will occur the next time that llcache_poll is called.
*/
/* ensure the source data is present */
error = llcache_retrieve_persisted_data(newest);
if (error == NSERROR_OK) {
/* source data was successfully retrieved from
* persistent store
*/
*result = newest;
return NSERROR_OK;
}
/* retrieval of source data from persistent store
* failed, destroy cache object and fall though to
* cache miss to re-fetch
*/
NSLOG(llcache, DEBUG, "Persistent retrieval failed for %p", newest);
llcache_object_remove_from_list(newest, &llcache->cached_objects);
llcache_object_destroy(newest);
error = llcache_object_new(url, &obj);
if (error != NSERROR_OK) {
return error;
}
} else if (newest != NULL) {
/* Found a candidate object but it needs freshness validation */
/* ensure the source data is present */
error = llcache_retrieve_persisted_data(newest);
if (error == NSERROR_OK) {
/* Create a new object */
error = llcache_object_new(url, &obj);
if (error != NSERROR_OK)
return error;
NSLOG(llcache, DEBUG, "Found candidate %p (%p)", obj, newest);
/* Clone candidate's cache data */
error = llcache_object_clone_cache_data(newest, obj, true);
if (error != NSERROR_OK) {
llcache_object_destroy(obj);
return error;
}
/* Record candidate, so we can fall back if it is still fresh */
newest->candidate_count++;
obj->candidate = newest;
/* Attempt to kick-off fetch */
error = llcache_object_fetch(obj, flags, referer, post,
redirect_count, hsts_in_use);
if (error != NSERROR_OK) {
newest->candidate_count--;
llcache_object_destroy(obj);
return error;
}
/* Add new object to cache */
llcache_object_add_to_list(obj, &llcache->cached_objects);
*result = obj;
return NSERROR_OK;
}
NSLOG(llcache, DEBUG, "Persistent retrieval failed for %p", newest);
/* retrieval of source data from persistent store
* failed, destroy cache object and fall though to
* cache miss to re-retch
*/
llcache_object_remove_from_list(newest,
&llcache->cached_objects);
llcache_object_destroy(newest);
error = llcache_object_new(url, &obj);
if (error != NSERROR_OK) {
return error;
}
}
/* Attempt to kick-off fetch */
error = llcache_object_fetch(obj, flags, referer, post,
redirect_count, hsts_in_use);
if (error != NSERROR_OK) {
llcache_object_destroy(obj);
return error;
}
/* Add new object to cache */
llcache_object_add_to_list(obj, &llcache->cached_objects);
*result = obj;
return NSERROR_OK;
}
/**
* Retrieve an object from the cache, fetching it if necessary.
*
* \param url URL of object to retrieve
* \param flags Fetch flags
* \param referer Referring URL, or NULL if none
* \param post POST data, or NULL for a GET request
* \param redirect_count Number of redirects followed so far
* \param hsts_in_use Whether HSTS applies to this fetch
* \param result Pointer to location to receive retrieved object
* \return NSERROR_OK on success, appropriate error otherwise
*/
static nserror
llcache_object_retrieve(nsurl *url,
uint32_t flags,
nsurl *referer,
const llcache_post_data *post,
uint32_t redirect_count,
bool hsts_in_use,
llcache_object **result)
{
nserror error;
llcache_object *obj;
nsurl *defragmented_url;
bool uncachable = false;
NSLOG(llcache, DEBUG, "Retrieve %s (%x, %s, %p)", nsurl_access(url), flags,
referer==NULL?"":nsurl_access(referer), post);
/* Get rid of any url fragment */
error = nsurl_defragment(url, &defragmented_url);
if (error != NSERROR_OK)
return error;
/* determine if content is cachable */
if ((flags & LLCACHE_RETRIEVE_FORCE_FETCH) != 0) {
/* Forced fetches are never cached */
uncachable = true;
} else if (post != NULL) {
/* POST requests are never cached */
uncachable = true;
} else {
/* only http and https schemes are cached */
lwc_string *scheme;
bool match;
scheme = nsurl_get_component(defragmented_url, NSURL_SCHEME);
if (lwc_string_caseless_isequal(scheme, corestring_lwc_http,
&match) == lwc_error_ok &&
(match == false)) {
if (lwc_string_caseless_isequal(scheme,
corestring_lwc_https, &match) ==
lwc_error_ok &&
(match == false)) {
uncachable = true;
}
}
lwc_string_unref(scheme);
}
if (uncachable) {
/* Create new object */
error = llcache_object_new(defragmented_url, &obj);
if (error != NSERROR_OK) {
nsurl_unref(defragmented_url);
return error;
}
/* Attempt to kick-off fetch */
error = llcache_object_fetch(obj, flags, referer, post,
redirect_count, hsts_in_use);
if (error != NSERROR_OK) {
llcache_object_destroy(obj);
nsurl_unref(defragmented_url);
return error;
}
/* Add new object to uncached list */
llcache_object_add_to_list(obj, &llcache->uncached_objects);
} else {
error = llcache_object_retrieve_from_cache(defragmented_url,
flags, referer, post, redirect_count,
hsts_in_use, &obj);
if (error != NSERROR_OK) {
nsurl_unref(defragmented_url);
return error;
}
/* Returned object is already in the cached list */
}
NSLOG(llcache, DEBUG, "Retrieved %p", obj);
*result = obj;
nsurl_unref(defragmented_url);
return NSERROR_OK;
}
/**
* Add a user to a low-level cache object
*
* \param object Object to add user to
* \param user User to add
* \return NSERROR_OK.
*/
static nserror llcache_object_add_user(llcache_object *object,
llcache_object_user *user)
{
assert(user->next == NULL);
assert(user->prev == NULL);
assert(user->handle != NULL);
user->handle->object = object;
user->prev = NULL;
user->next = object->users;
if (object->users != NULL)
object->users->prev = user;
object->users = user;
NSLOG(llcache, DEBUG, "Adding user %p to %p", user, object);
return NSERROR_OK;
}
/**
* Transform a request-URI based on HSTS policy
*
* \param url URL to transform
* \param result Pointer to location to receive transformed URL
* \param hsts_in_use Pointer to location to receive HSTS in-use flag
* \return NSERROR_OK on success, appropriate error otherwise
*/
static nserror llcache_hsts_transform_url(nsurl *url, nsurl **result,
bool *hsts_in_use)
{
lwc_string *scheme = NULL;
bool match;
nserror error = NSERROR_OK;
scheme = nsurl_get_component(url, NSURL_SCHEME);
if (lwc_string_caseless_isequal(scheme, corestring_lwc_http,
&match) != lwc_error_ok || match == false) {
/* Non-HTTP fetch: ignore */
lwc_string_unref(scheme);
*result = nsurl_ref(url);
*hsts_in_use = false;
return error;
}
lwc_string_unref(scheme);
if (urldb_get_hsts_enabled(url)) {
/* Only need to force HTTPS. If original port was explicitly
* specified as 80, nsurl_create/join will remove it (as
* it's redundant) */
error = nsurl_replace_scheme(url, corestring_lwc_https,
result);
*hsts_in_use = (error == NSERROR_OK);
} else {
*result = nsurl_ref(url);
*hsts_in_use = false;
}
return error;
}
/**
* Update HSTS policy for target domain.
*
* \param object Newly-fetched cache object
* \return NSERROR_OK on success, appropriate error otherwise
*/
static nserror llcache_hsts_update_policy(llcache_object *object)
{
size_t i;
lwc_string *scheme = NULL;
bool match = false;
scheme = nsurl_get_component(object->url, NSURL_SCHEME);
if (lwc_string_caseless_isequal(scheme, corestring_lwc_https,
&match) != lwc_error_ok || match == false) {
/* Non-HTTPS fetch: ignore */
lwc_string_unref(scheme);
return NSERROR_OK;
}
lwc_string_unref(scheme);
if (object->fetch.tainted_tls) {
/* Transport is tainted: ignore */
return NSERROR_OK;
}
for (i = 0; i < object->num_headers; i++) {
if (strcasecmp("Strict-Transport-Security",
object->headers[i].name) == 0) {
urldb_set_hsts_policy(object->url,
object->headers[i].value);
/* Only process the first one we find */
break;
}
}
return NSERROR_OK;
}
/**
* Handle FETCH_REDIRECT event
*
* \param object Object being redirected
* \param target Target of redirect (may be relative)
* \param replacement Pointer to location to receive replacement object
* \return NSERROR_OK on success, appropriate error otherwise
*/
static nserror llcache_fetch_redirect(llcache_object *object,
const char *target, llcache_object **replacement)
{
nserror error;
llcache_object *dest;
llcache_object_user *user, *next;
const llcache_post_data *post = object->fetch.post;
nsurl *url, *hsts_url;
lwc_string *scheme;
lwc_string *object_scheme;
bool match, hsts_in_use;
/* Extract HTTP response code from the fetch object */
long http_code = fetch_http_code(object->fetch.fetch);
llcache_event event;
/* Abort fetch for this object */
fetch_abort(object->fetch.fetch);
object->fetch.fetch = NULL;
/* Invalidate the cache control data */
llcache_invalidate_cache_control_data(object);
/* And mark it complete */
object->fetch.state = LLCACHE_FETCH_COMPLETE;
(void) llcache_hsts_update_policy(object);
/* Forcibly stop redirecting if we've followed too many redirects */
#define REDIRECT_LIMIT 10
if (object->fetch.redirect_count > REDIRECT_LIMIT) {
NSLOG(llcache, INFO, "Too many nested redirects");
event.type = LLCACHE_EVENT_ERROR;
event.data.error.code = NSERROR_BAD_REDIRECT;
event.data.error.msg = messages_get("BadRedirect");
return llcache_send_event_to_users(object, &event);
}
#undef REDIRECT_LIMIT
/* Make target absolute */
error = nsurl_join(object->url, target, &url);
if (error != NSERROR_OK)
return error;
/* Perform HSTS transform */
error = llcache_hsts_transform_url(url, &hsts_url, &hsts_in_use);
if (error != NSERROR_OK) {
nsurl_unref(url);
return error;
}
nsurl_unref(url);
/* Inform users of redirect */
event.type = LLCACHE_EVENT_REDIRECT;
event.data.redirect.from = object->url;
event.data.redirect.to = hsts_url;
error = llcache_send_event_to_users(object, &event);
if (error != NSERROR_OK) {
nsurl_unref(hsts_url);
return error;
}
/* Reject attempts to redirect from unvalidated to validated schemes
* A "validated" scheme is one over which we have some guarantee that
* the source is trustworthy. */
object_scheme = nsurl_get_component(object->url, NSURL_SCHEME);
scheme = nsurl_get_component(hsts_url, NSURL_SCHEME);
/* resource: and about: are allowed to redirect anywhere */
if ((lwc_string_isequal(object_scheme, corestring_lwc_resource,
&match) == lwc_error_ok && match == false) &&
(lwc_string_isequal(object_scheme, corestring_lwc_about,
&match) == lwc_error_ok && match == false)) {
/* file, about and resource are not valid redirect targets */
if ((lwc_string_isequal(object_scheme, corestring_lwc_file,
&match) == lwc_error_ok && match == true) ||
(lwc_string_isequal(object_scheme, corestring_lwc_about,
&match) == lwc_error_ok && match == true) ||
(lwc_string_isequal(object_scheme, corestring_lwc_resource,
&match) == lwc_error_ok && match == true)) {
lwc_string_unref(object_scheme);
lwc_string_unref(scheme);
nsurl_unref(hsts_url);
return NSERROR_OK;
}
}
lwc_string_unref(scheme);
lwc_string_unref(object_scheme);
/* Bail out if we've no way of handling this URL */
if (fetch_can_fetch(hsts_url) == false) {
nsurl_unref(hsts_url);
return NSERROR_OK;
}
if (http_code == 301 || http_code == 302 || http_code == 303) {
/* 301, 302, 303 redirects are all unconditional GET requests */
post = NULL;
} else if (http_code != 307 || post != NULL) {
/** \todo 300, 305, 307 with POST */
nsurl_unref(hsts_url);
return NSERROR_OK;
}
/* Attempt to fetch target URL */
error = llcache_object_retrieve(hsts_url, object->fetch.flags,
object->fetch.referer, post,
object->fetch.redirect_count + 1,
hsts_in_use, &dest);
/* No longer require url */
nsurl_unref(hsts_url);
if (error != NSERROR_OK)
return error;
/* Move user(s) to replacement object */
for (user = object->users; user != NULL; user = next) {
next = user->next;
llcache_object_remove_user(object, user);
llcache_object_add_user(dest, user);
}
/* Dest is now our object */
*replacement = dest;
return NSERROR_OK;
}
/**
* Update an object's cache state
*
* \param object Object to update cache for
* \return NSERROR_OK.
*/
static nserror llcache_object_cache_update(llcache_object *object)
{
if (object->cache.date == 0)
object->cache.date = time(NULL);
return NSERROR_OK;
}
/**
* Handle FETCH_NOTMODIFIED event
*
* \param object Object to process
* \param replacement Pointer to location to receive replacement object
* \return NSERROR_OK.
*/
static nserror llcache_fetch_notmodified(llcache_object *object,
llcache_object **replacement)
{
/* There may be no candidate if the server erroneously responded
* to an unconditional request with a 304 Not Modified response.
* In this case, we simply retain the initial object, having
* invalidated it and marked it as complete.
*/
if (object->candidate != NULL) {
llcache_object_user *user, *next;
/* Move user(s) to candidate content */
for (user = object->users; user != NULL; user = next) {
next = user->next;
llcache_object_remove_user(object, user);
llcache_object_add_user(object->candidate, user);
}
/* Candidate is no longer a candidate for us */
object->candidate->candidate_count--;
/* Clone our cache control data into the candidate */
llcache_object_clone_cache_data(object, object->candidate,
false);
/* Bring candidate's cache data up to date */
llcache_object_cache_update(object->candidate);
/* Revert no-cache to normal, if required */
if (object->candidate->cache.no_cache ==
LLCACHE_VALIDATE_ONCE) {
object->candidate->cache.no_cache =
LLCACHE_VALIDATE_FRESH;
}
/* Candidate is now our object */
*replacement = object->candidate;
object->candidate = NULL;
} else {
/* There was no candidate: retain object */
*replacement = object;
}
/* Ensure fetch has stopped */
fetch_abort(object->fetch.fetch);
object->fetch.fetch = NULL;
/* Invalidate our cache-control data */
llcache_invalidate_cache_control_data(object);
/* Mark it complete */
object->fetch.state = LLCACHE_FETCH_COMPLETE;
(void) llcache_hsts_update_policy(object);
/* Old object will be flushed from the cache on the next poll */
return NSERROR_OK;
}
/**
* Process a chunk of fetched data
*
* \param object Object being fetched
* \param data Data to process
* \param len Byte length of data
* \return NSERROR_OK on success, appropriate error otherwise.
*/
static nserror
llcache_fetch_process_data(llcache_object *object,
const uint8_t *data,
size_t len)
{
if (object->fetch.state != LLCACHE_FETCH_DATA) {
/**
* \note
* On entry into this state, check if we need to
* invalidate the cache control data. We are guaranteed
* to have received all response headers.
*
* There are two cases in which we want to suppress
* cacheing of an object:
*
* 1) The HTTP response code is not 200 or 203
* 2) The request URI had a query string and the
* response headers did not provide an explicit
* object expiration time.
*/
long http_code = fetch_http_code(object->fetch.fetch);
if ((http_code != 200 && http_code != 203) ||
(nsurl_has_component(object->url, NSURL_QUERY) &&
(object->cache.max_age == INVALID_AGE &&
object->cache.expires == 0))) {
/* Invalidate cache control data */
llcache_invalidate_cache_control_data(object);
}
/* Release candidate, if any */
if (object->candidate != NULL) {
object->candidate->candidate_count--;
object->candidate = NULL;
}
object->fetch.state = LLCACHE_FETCH_DATA;
}
/* Resize source buffer if it's too small */
if (object->source_len + len >= object->source_alloc) {
const size_t new_len = object->source_len + len + 64 * 1024;
uint8_t *temp = realloc(object->source_data, new_len);
if (temp == NULL)
return NSERROR_NOMEM;
object->source_data = temp;
object->source_alloc = new_len;
}
/* Append this data chunk to source buffer */
memcpy(object->source_data + object->source_len, data, len);
object->source_len += len;
return NSERROR_OK;
}
/**
* Handle an authentication request
*
* \param object Object being fetched
* \param realm Authentication realm
* \return NSERROR_OK on success, appropriate error otherwise.
*/
static nserror llcache_fetch_auth(llcache_object *object, const char *realm)
{
const char *auth;
nserror error = NSERROR_OK;
/* Abort fetch for this object */
fetch_abort(object->fetch.fetch);
object->fetch.fetch = NULL;
/* Invalidate cache-control data */
llcache_invalidate_cache_control_data(object);
/* Destroy headers */
llcache_destroy_headers(object);
/* If there was no realm, then default to the URL */
/** \todo If there was no WWW-Authenticate header, use response body */
if (realm == NULL)
realm = nsurl_access(object->url);
auth = urldb_get_auth_details(object->url, realm);
if (auth == NULL || object->fetch.tried_with_auth == true) {
llcache_event event;
/* No authentication details, or tried what we had, so ask */
object->fetch.tried_with_auth = false;
/* Mark object complete */
object->fetch.state = LLCACHE_FETCH_COMPLETE;
/* Inform client(s) that object fetch failed */
event.type = LLCACHE_EVENT_ERROR;
/** \todo More appropriate error message */
event.data.error.code = NSERROR_BAD_AUTH;
event.data.error.msg = realm;
error = llcache_send_event_to_users(object, &event);
} else {
/* Flag that we've tried to refetch with credentials, so
* that if the fetch fails again, we ask the user again */
object->fetch.tried_with_auth = true;
error = llcache_object_refetch(object);
}
return error;
}
/**
* Handle a TLS certificate verification failure
*
* \param object Object being fetched
* \return NSERROR_OK on success, appropriate error otherwise
*/
static nserror llcache_fetch_cert_error(llcache_object *object)
{
nserror error = NSERROR_OK;
/* Fetch has been stopped, and destroyed. Invalidate object's pointer */
object->fetch.fetch = NULL;
/* Invalidate cache-control data */
llcache_invalidate_cache_control_data(object);
/* Consider the TLS transport tainted */
object->fetch.tainted_tls = true;
/* Only give the user a chance if HSTS isn't in use for this fetch */
if (object->fetch.hsts_in_use == false) {
llcache_event event;
/* Mark object complete */
object->fetch.state = LLCACHE_FETCH_COMPLETE;
/* Inform client(s) that object fetch failed */
event.type = LLCACHE_EVENT_ERROR;
/** \todo More appropriate error message */
event.data.error.code = NSERROR_BAD_CERTS;
event.data.error.msg = messages_get("FetchFailed");
error = llcache_send_event_to_users(object, &event);
} else {
llcache_event event;
/* Mark object complete */
object->fetch.state = LLCACHE_FETCH_COMPLETE;
/* Inform client(s) that object fetch failed */
event.type = LLCACHE_EVENT_ERROR;
/** \todo More appropriate error message */
event.data.error.code = NSERROR_UNKNOWN;
event.data.error.msg = messages_get("FetchFailed");
error = llcache_send_event_to_users(object, &event);
}
return error;
}
/**
* Handle a TLS connection setup failure
*
* \param object Object being fetched
* \return NSERROR_OK on success, appropriate error otherwise
*/
static nserror llcache_fetch_ssl_error(llcache_object *object)
{
nserror error = NSERROR_OK;
/* Fetch has been stopped, and destroyed. Invalidate object's pointer */
object->fetch.fetch = NULL;
/* Invalidate cache-control data */
llcache_invalidate_cache_control_data(object);
/* Consider the TLS transport tainted */
object->fetch.tainted_tls = true;
/* Make no attempt to downgrade if HSTS is in use
* (i.e. assume server does TLS properly) */
if (object->fetch.hsts_in_use ||
object->fetch.tried_with_tls_downgrade) {
/* Have already tried to downgrade, so give up */
llcache_event event;
/* Mark object complete */
object->fetch.state = LLCACHE_FETCH_COMPLETE;
/* Inform client(s) that object fetch failed */
event.type = LLCACHE_EVENT_ERROR;
/** \todo More appropriate error message */
event.data.error.code = NSERROR_UNKNOWN;
event.data.error.msg = messages_get("FetchFailed");
error = llcache_send_event_to_users(object, &event);
} else {
/* Flag that we've tried to downgrade, so that if the
* fetch fails again, we give up */
object->fetch.tried_with_tls_downgrade = true;
error = llcache_object_refetch(object);
}
return error;
}
/**
* Construct a sorted list of objects available for writeout operation.
*
* The list contains fresh cacheable objects held in RAM with no
* pending fetches. Any objects with a remaining lifetime less than
* the configured minimum lifetime are simply not considered, they will
* become stale before pushing to backing store is worth the cost.
*
* \todo calculate useful cost metrics to improve sorting.
*
* \param[out] lst_out list of candidate objects.
* \param[out] lst_len_out Number of candidate objects in result.
* \return NSERROR_OK with \a lst_out and \a lst_len_out updated or
* error code.
*/
static nserror
build_candidate_list(struct llcache_object ***lst_out, int *lst_len_out)
{
llcache_object *object, *next;
struct llcache_object **lst;
int lst_len = 0;
int remaining_lifetime;
#define MAX_PERSIST_PER_RUN 128
lst = calloc(MAX_PERSIST_PER_RUN, sizeof(struct llcache_object *));
if (lst == NULL) {
return NSERROR_NOMEM;
}
for (object = llcache->cached_objects; object != NULL; object = next) {
next = object->next;
remaining_lifetime = llcache_object_rfc2616_remaining_lifetime(
&object->cache);
/* cacehable objects with no pending fetches, not
* already on disc and with sufficient lifetime to
* make disc cache worthwhile
*/
if ((object->candidate_count == 0) &&
(object->fetch.fetch == NULL) &&
(object->store_state == LLCACHE_STATE_RAM) &&
(remaining_lifetime > llcache->minimum_lifetime)) {
lst[lst_len] = object;
lst_len++;
if (lst_len == MAX_PERSIST_PER_RUN)
break;
}
}
if (lst_len == 0) {
free(lst);
return NSERROR_NOT_FOUND;
}
/** \todo sort list here */
*lst_len_out = lst_len;
*lst_out = lst;
#undef MAX_PERSIST_PER_RUN
return NSERROR_OK;
}
/**
* Write an object to the backing store.
*
* \param object The object to put in the backing store.
* \param written_out The amount of data written out.
* \param elapsed The time in ms it took to complete the write to backing store.
* \return NSERROR_OK on success or appropriate error code.
*/
static nserror
write_backing_store(struct llcache_object *object,
size_t *written_out,
unsigned long *elapsed)
{
nserror ret;
uint8_t *metadata;
size_t metadatasize;
uint64_t startms = 0;
uint64_t endms = 1000;
nsu_getmonotonic_ms(&startms);
/* put object data in backing store */
ret = guit->llcache->store(object->url,
BACKING_STORE_NONE,
object->source_data,
object->source_len);
if (ret != NSERROR_OK) {
/* unable to put source data in backing store */
return ret;
}
ret = llcache_serialise_metadata(object, &metadata, &metadatasize);
if (ret != NSERROR_OK) {
/* There has been a metadata serialisation error. Ensure the
* already written data object is invalidated.
*/
guit->llcache->invalidate(object->url);
return ret;
}
ret = guit->llcache->store(object->url,
BACKING_STORE_META,
metadata,
metadatasize);
guit->llcache->release(object->url, BACKING_STORE_META);
if (ret != NSERROR_OK) {
/* There has been an error putting the metadata in the
* backing store. Ensure the data object is invalidated.
*/
guit->llcache->invalidate(object->url);
return ret;
}
nsu_getmonotonic_ms(&endms);
object->store_state = LLCACHE_STATE_DISC;
*written_out = object->source_len + metadatasize;
/* by ignoring the overflow this assumes the writeout took
* less than 5 weeks.
*/
*elapsed = endms - startms;
/* ensure the writeout is reported to have taken at least the
* minimal amount of time
*/
if (*elapsed == 0) {
*elapsed = 1;
}
return NSERROR_OK;
}
/**
* Check for overall write performance.
*
* If the overall write bandwidth has fallen below a useful level for
* the backing store to be effective disable it.
*
* It is important to ensure a useful amount of data has been written
* before calculating bandwidths otherwise tiny files taking a
* disproportionately long time to write might trigger this erroneously.
*
* \param p The context pointer passed to the callback.
*/
static void llcache_persist_slowcheck(void *p)
{
uint64_t total_bandwidth; /* total bandwidth */
if (llcache->total_written > (2 * llcache->minimum_bandwidth)) {
total_bandwidth = (llcache->total_written * 1000) / llcache->total_elapsed;
if (total_bandwidth < llcache->minimum_bandwidth) {
NSLOG(llcache, INFO,
"Current bandwidth %"PRIu64" less than minimum %"PRIsizet,
total_bandwidth,
llcache->minimum_bandwidth);
guit->llcache->finalise();
}
}
}
/**
* Possibly write objects data to backing store.
*
* \param p The context pointer passed to the callback.
*/
static void llcache_persist(void *p)
{
nserror ret;
struct llcache_object **lst; /* candidate object list */
int lst_count; /* number of candidates in list */
int idx; /* current candidate object index in list */
int next = -1; /* when the next run should be scheduled for */
unsigned long write_limit; /* max number of bytes to write in this run*/
size_t written; /* all bytes written for a single object */
unsigned long elapsed; /* how long writing an object took */
size_t total_written = 0; /* total bytes written in this run */
unsigned long total_elapsed = 1; /* total ms used to write bytes */
unsigned long total_bandwidth = 0; /* total bandwidth */
ret = build_candidate_list(&lst, &lst_count);
if (ret != NSERROR_OK) {
NSLOG(llcache, DEBUG, "Unable to construct candidate list for persistent writeout");
return;
}
write_limit = (llcache->maximum_bandwidth * llcache->time_quantum) / 1000;
/* obtained a candidate list, make each object persistent in turn */
for (idx = 0; idx < lst_count; idx++) {
ret = write_backing_store(lst[idx], &written, &elapsed);
if (ret != NSERROR_OK) {
continue;
}
/* successfully wrote object to backing store */
total_written += written;
total_elapsed += elapsed;
total_bandwidth = (total_written * 1000) / total_elapsed;
NSLOG(llcache, DEBUG,
"Wrote %"PRIssizet" bytes in %lums bw:%lu %s",
written, elapsed, (written * 1000) / elapsed,
nsurl_access(lst[idx]->url) );
/* check to for the time quantum or the size
* (bandwidth) for this run being exceeded.
*/
if (total_elapsed > llcache->time_quantum) {
NSLOG(llcache, INFO, "Overran timeslot");
/* writeout has exhausted the available time.
* Either the writeout is slow or the last
* object was very large.
*/
if (total_bandwidth < llcache->minimum_bandwidth) {
/* Writeout was slow in this time quantum.
* Schedule a check in the future to see if
* overall performance is too slow to be useful.
*/
guit->misc->schedule(
llcache->time_quantum * 100,
llcache_persist_slowcheck,
NULL);
break;
} else {
if (total_bandwidth > llcache->maximum_bandwidth) {
/* fast writeout of large file
* so calculate delay as if
* write happened only at max
* limit
*/
next = ((total_written * llcache->time_quantum) / write_limit) - total_elapsed;
} else {
next = llcache->time_quantum;
}
break;
}
} else if (total_written > write_limit) {
/* The bandwidth limit has been reached. */
if (total_bandwidth > llcache->maximum_bandwidth) {
/* fast writeout of large file so
* calculate delay as if write
* happened only at max limit
*/
next = ((total_written * llcache->time_quantum) / write_limit) - total_elapsed;
} else {
next = llcache->time_quantum - total_elapsed;
}
break;
}
}
free(lst);
/* Completed list without running out of allowed bytes or time */
if (idx == lst_count) {
/* only reschedule if writing is making any progress at all */
if (total_written > 0) {
next = llcache->time_quantum - total_elapsed;
} else {
next = -1;
}
}
llcache->total_written += total_written;
llcache->total_elapsed += total_elapsed;
NSLOG(llcache, DEBUG,
"writeout size:%"PRIssizet" time:%lu bandwidth:%lubytes/s",
total_written, total_elapsed, total_bandwidth);
NSLOG(llcache, DEBUG, "Rescheduling writeout in %dms", next);
guit->misc->schedule(next, llcache_persist, NULL);
}
/**
* Handler for fetch events
*
* \param msg Fetch event
* \param p Our private data
*/
static void llcache_fetch_callback(const fetch_msg *msg, void *p)
{
nserror error = NSERROR_OK;
llcache_object *object = p;
llcache_event event;
if (llcache == NULL) {
NSLOG(llcache, CRITICAL, "Callback happened after llcache finalisation");
assert(false);
/* In case assertions are off, return here */
return;
}
NSLOG(llcache, DEBUG, "Fetch event %d for %p", msg->type, object);
switch (msg->type) {
case FETCH_HEADER:
/* Received a fetch header */
object->fetch.state = LLCACHE_FETCH_HEADERS;
error = llcache_fetch_process_header(object,
msg->data.header_or_data.buf,
msg->data.header_or_data.len);
break;
/* 3xx responses */
case FETCH_REDIRECT:
/* Request resulted in a redirect */
/* Release candidate, if any */
if (object->candidate != NULL) {
object->candidate->candidate_count--;
object->candidate = NULL;
}
error = llcache_fetch_redirect(object,
msg->data.redirect, &object);
break;
case FETCH_NOTMODIFIED:
/* Conditional request determined that cached object is fresh */
error = llcache_fetch_notmodified(object, &object);
break;
/* Normal 2xx state machine */
case FETCH_DATA:
/* Received some data */
error = llcache_fetch_process_data(object,
msg->data.header_or_data.buf,
msg->data.header_or_data.len);
break;
case FETCH_FINISHED:
/* Finished fetching */
{
uint8_t *temp;
object->fetch.state = LLCACHE_FETCH_COMPLETE;
object->fetch.fetch = NULL;
/* Shrink source buffer to required size */
temp = realloc(object->source_data,
object->source_len);
/* If source_len is 0, then temp may be NULL */
if (temp != NULL || object->source_len == 0) {
object->source_data = temp;
object->source_alloc = object->source_len;
}
llcache_object_cache_update(object);
/* record when the fetch finished */
object->cache.fin_time = time(NULL);
(void) llcache_hsts_update_policy(object);
guit->misc->schedule(5000, llcache_persist, NULL);
}
break;
/* Out-of-band information */
case FETCH_TIMEDOUT:
/* Timed out while trying to fetch. */
/* The fetch has already been cleaned up by the fetcher but
* we would like to retry if we can. */
if (object->fetch.retries_remaining > 1) {
object->fetch.retries_remaining--;
error = llcache_object_refetch(object);
break;
}
/* Fall through */
case FETCH_ERROR:
/* An error occurred while fetching */
/* The fetch has has already been cleaned up by the fetcher */
object->fetch.state = LLCACHE_FETCH_COMPLETE;
object->fetch.fetch = NULL;
/* Release candidate, if any */
if (object->candidate != NULL) {
object->candidate->candidate_count--;
object->candidate = NULL;
}
/* Invalidate cache control data */
llcache_invalidate_cache_control_data(object);
/** \todo Consider using errorcode for something */
event.type = LLCACHE_EVENT_ERROR;
event.data.error.code = NSERROR_UNKNOWN;
event.data.error.msg = msg->data.error;
error = llcache_send_event_to_users(object, &event);
break;
case FETCH_PROGRESS:
/* Progress update */
event.type = LLCACHE_EVENT_PROGRESS;
event.data.progress_msg = msg->data.progress;
error = llcache_send_event_to_users(object, &event);
break;
case FETCH_CERTS:
/* Certificate information from the fetch */
/** \todo CERTS - Should we persist this on the object and
* then catch up new users etc?
*/
event.type = LLCACHE_EVENT_GOT_CERTS;
event.data.certs.certs = msg->data.certs.certs;
event.data.certs.num = msg->data.certs.num_certs;
error = llcache_send_event_to_users(object, &event);
break;
/* Events requiring action */
case FETCH_AUTH:
/* Need Authentication */
/* Release candidate, if any */
if (object->candidate != NULL) {
object->candidate->candidate_count--;
object->candidate = NULL;
}
error = llcache_fetch_auth(object, msg->data.auth.realm);
break;
case FETCH_CERT_ERR:
/* Something went wrong when validating TLS certificates */
/* Release candidate, if any */
if (object->candidate != NULL) {
object->candidate->candidate_count--;
object->candidate = NULL;
}
error = llcache_fetch_cert_error(object);
break;
case FETCH_SSL_ERR:
/* TLS connection setup failed */
/* Release candidate, if any */
if (object->candidate != NULL) {
object->candidate->candidate_count--;
object->candidate = NULL;
}
error = llcache_fetch_ssl_error(object);
break;
}
/* Deal with any errors reported by event handlers */
if (error != NSERROR_OK) {
if (error == NSERROR_NOMEM) {
/* attempt to purge the cache to free some
* memory. will not help this fetch, but may
* allow the UI to report errors etc.
*/
llcache_clean(true);
}
if (object->fetch.fetch != NULL) {
fetch_abort(object->fetch.fetch);
object->fetch.fetch = NULL;
/* Invalidate cache control data */
llcache_invalidate_cache_control_data(object);
object->fetch.state = LLCACHE_FETCH_COMPLETE;
}
}
/* There may be users which are not caught up so schedule ourselves */
llcache_users_not_caught_up();
}
/**
* Find a user of a low-level cache object
*
* \param handle External cache handle to search for
* \return Pointer to corresponding user, or NULL if not found
*/
static llcache_object_user *llcache_object_find_user(
const llcache_handle *handle)
{
llcache_object_user *user;
assert(handle->object != NULL);
for (user = handle->object->users; user != NULL; user = user->next) {
if (user->handle == handle)
break;
}
return user;
}
/**
* Determine if a low-level cache object resides in a given list
*
* \param object Object to search for
* \param list List to search in
* \return True if object resides in list, false otherwise
*/
static bool llcache_object_in_list(const llcache_object *object,
const llcache_object *list)
{
while (list != NULL) {
if (list == object)
break;
list = list->next;
}
return list != NULL;
}
/**
* Notify users of an object's current state
*
* \param object Object to notify users about
* \return NSERROR_OK on success, appropriate error otherwise
*/
static nserror llcache_object_notify_users(llcache_object *object)
{
nserror error;
llcache_object_user *user, *next_user;
llcache_event event;
bool emitted_notify = false;
/**
* State transitions and event emission for users.
* Rows: user state. Cols: object state.
*
* User - Obj INIT HEADERS DATA COMPLETE
* INIT - T T* T*
* HEADERS - - T T*
* DATA - - M T
* COMPLETE - - - -
*
* T => transition user to object state
* M => no transition required, but may need to emit event
*
* The transitions marked with an asterisk can be removed by moving
* the user context into the subsequent state and then reevaluating.
*
* Events are issued as follows:
*
* HAD_HEADERS: on transition from HEADERS -> DATA state
* HAD_DATA : in DATA state, whenever there's new source data
* DONE : on transition from DATA -> COMPLETE state
*/
for (user = object->users; user != NULL; user = next_user) {
/* Emit necessary events to bring the user up-to-date */
llcache_handle *handle = user->handle;
const llcache_fetch_state objstate = object->fetch.state;
/* Flag that this user is the current iteration target
* in case the client attempts to destroy it underneath us */
user->iterator_target = true;
/* A note on the computation of next_user:
*
* Within this loop, we may make a number of calls to
* client code. Our contract with clients is that they
* can do whatever they like from within their callback
* handlers. This is so that we limit the pain of
* reentrancy to this module alone.
*
* One of the things a client can do from within its
* callback handler is to remove users from this object's
* user list. In the common case, the user they attempt
* to remove is the current iteration target, and we
* already protect against that causing problems here.
* However, no such protection exists if the client
* attempts to remove other users from this object's
* user list.
*
* Therefore, we cannot compute next_user up-front
* and expect it to remain valid across calls to
* client code (as the identity of the next user
* in the list may change underneath us). Instead,
* we must compute next_user at the point where we
* are about to cause another iteration of this loop
* (i.e. at the very end, and also at the points where
* continue is used)
*/
if (handle->state != objstate) {
if (emitted_notify == false) {
NSLOG(llcache, DEBUG,
"Notifying users of %p",
object);
emitted_notify = true;
}
NSLOG(llcache, DEBUG,
"User %p state: %d Object state: %d",
user,
handle->state,
objstate);
}
/* User: INIT, Obj: HEADERS, DATA, COMPLETE => User->HEADERS */
if (handle->state == LLCACHE_FETCH_INIT &&
objstate > LLCACHE_FETCH_INIT) {
handle->state = LLCACHE_FETCH_HEADERS;
}
/* User: HEADERS, Obj: DATA, COMPLETE => User->DATA */
if (handle->state == LLCACHE_FETCH_HEADERS &&
objstate > LLCACHE_FETCH_HEADERS) {
handle->state = LLCACHE_FETCH_DATA;
/* Emit HAD_HEADERS event */
event.type = LLCACHE_EVENT_HAD_HEADERS;
error = handle->cb(handle, &event, handle->pw);
if (user->queued_for_delete) {
next_user = user->next;
llcache_object_remove_user(object, user);
llcache_object_user_destroy(user);
if (error != NSERROR_OK)
return error;
continue;
} else if (error == NSERROR_NEED_DATA) {
/* User requested replay */
handle->state = LLCACHE_FETCH_HEADERS;
/* Continue with the next user -- we'll
* reemit the event next time round */
user->iterator_target = false;
next_user = user->next;
llcache_users_not_caught_up();
continue;
} else if (error != NSERROR_OK) {
user->iterator_target = false;
return error;
}
}
/* User: DATA, Obj: DATA, COMPLETE, more source available */
if (handle->state == LLCACHE_FETCH_DATA &&
objstate >= LLCACHE_FETCH_DATA &&
object->source_len > handle->bytes) {
size_t orig_handle_read;
/* Construct HAD_DATA event */
event.type = LLCACHE_EVENT_HAD_DATA;
event.data.data.buf =
object->source_data + handle->bytes;
event.data.data.len =
object->source_len - handle->bytes;
/* Update record of last byte emitted */
if (object->fetch.flags &
LLCACHE_RETRIEVE_STREAM_DATA) {
/* Streaming, so reset to zero to
* minimise amount of cached source data.
* Additionally, we don't support replay
* when streaming. */
orig_handle_read = 0;
handle->bytes = object->source_len = 0;
} else {
orig_handle_read = handle->bytes;
handle->bytes = object->source_len;
}
/* Emit event */
error = handle->cb(handle, &event, handle->pw);
if (user->queued_for_delete) {
next_user = user->next;
llcache_object_remove_user(object, user);
llcache_object_user_destroy(user);
if (error != NSERROR_OK)
return error;
continue;
} else if (error == NSERROR_NEED_DATA) {
/* User requested replay */
handle->bytes = orig_handle_read;
/* Continue with the next user -- we'll
* reemit the data next time round */
user->iterator_target = false;
next_user = user->next;
llcache_users_not_caught_up();
continue;
} else if (error != NSERROR_OK) {
user->iterator_target = false;
return error;
}
}
/* User: DATA, Obj: COMPLETE => User->COMPLETE */
if (handle->state == LLCACHE_FETCH_DATA &&
objstate > LLCACHE_FETCH_DATA) {
handle->state = LLCACHE_FETCH_COMPLETE;
/* Emit DONE event */
event.type = LLCACHE_EVENT_DONE;
error = handle->cb(handle, &event, handle->pw);
if (user->queued_for_delete) {
next_user = user->next;
llcache_object_remove_user(object, user);
llcache_object_user_destroy(user);
if (error != NSERROR_OK)
return error;
continue;
} else if (error == NSERROR_NEED_DATA) {
/* User requested replay */
handle->state = LLCACHE_FETCH_DATA;
/* Continue with the next user -- we'll
* reemit the event next time round */
user->iterator_target = false;
next_user = user->next;
llcache_users_not_caught_up();
continue;
} else if (error != NSERROR_OK) {
user->iterator_target = false;
return error;
}
}
/* No longer the target of an iterator */
user->iterator_target = false;
next_user = user->next;
}
return NSERROR_OK;
}
/**
* Make a snapshot of the current state of an llcache_object.
*
* This has the side-effect of the new object being non-cacheable,
* also not-fetching and not a candidate for any other object.
*
* Also note that this new object has no users and at least one
* should be assigned to it before llcache_clean is entered or it
* will be immediately cleaned up.
*
* \param object The object to take a snapshot of
* \param snapshot Pointer to receive snapshot of \a object
* \return NSERROR_OK on success, appropriate error otherwise
*/
static nserror
llcache_object_snapshot(llcache_object *object, llcache_object **snapshot)
{
llcache_object *newobj;
nserror error;
error = llcache_object_new(object->url, &newobj);
if (error != NSERROR_OK)
return error;
newobj->source_alloc = newobj->source_len = object->source_len;
if (object->source_len > 0) {
newobj->source_data = malloc(newobj->source_alloc);
if (newobj->source_data == NULL) {
llcache_object_destroy(newobj);
return NSERROR_NOMEM;
}
memcpy(newobj->source_data, object->source_data,
newobj->source_len);
}
if (object->num_headers > 0) {
newobj->headers = calloc(sizeof(llcache_header),
object->num_headers);
if (newobj->headers == NULL) {
llcache_object_destroy(newobj);
return NSERROR_NOMEM;
}
while (newobj->num_headers < object->num_headers) {
llcache_header *nh =
&(newobj->headers[newobj->num_headers]);
llcache_header *oh =
&(object->headers[newobj->num_headers]);
newobj->num_headers += 1;
nh->name = strdup(oh->name);
nh->value = strdup(oh->value);
if (nh->name == NULL || nh->value == NULL) {
llcache_object_destroy(newobj);
return NSERROR_NOMEM;
}
}
}
newobj->fetch.state = LLCACHE_FETCH_COMPLETE;
*snapshot = newobj;
return NSERROR_OK;
}
/**
* total ram usage of object
*
* \param object The object to calculate the total RAM usage of.
* \return The total RAM usage in bytes.
*/
static inline uint32_t
total_object_size(llcache_object *object)
{
uint32_t tot;
size_t hdrc;
tot = sizeof(*object);
tot += nsurl_length(object->url);
if (object->source_data != NULL) {
tot += object->source_len;
}
tot += sizeof(llcache_header) * object->num_headers;
for (hdrc = 0; hdrc < object->num_headers; hdrc++) {
if (object->headers[hdrc].name != NULL) {
tot += strlen(object->headers[hdrc].name);
}
if (object->headers[hdrc].value != NULL) {
tot += strlen(object->headers[hdrc].value);
}
}
return tot;
}
/******************************************************************************
* Public API *
******************************************************************************/
/*
* Attempt to clean the cache
*
* The memory cache cleaning discards objects in order of increasing value.
*
* Exported interface documented in llcache.h
*/
void llcache_clean(bool purge)
{
llcache_object *object, *next;
uint32_t llcache_size = 0;
int remaining_lifetime;
uint32_t limit;
NSLOG(llcache, DEBUG, "Attempting cache clean");
/* If the cache is being purged set the size limit to zero. */
if (purge) {
limit = 0;
} else {
limit = llcache->limit;
}
/* Uncacheable objects with no users or fetches */
for (object = llcache->uncached_objects;
object != NULL;
object = next) {
next = object->next;
/* The candidate count of uncacheable objects is always 0 */
if ((object->users == NULL) &&
(object->candidate_count == 0) &&
(object->fetch.fetch == NULL)) {
NSLOG(llcache, DEBUG, "Discarding uncachable object with no users (%p) %s",
object, nsurl_access(object->url));
llcache_object_remove_from_list(object,
&llcache->uncached_objects);
llcache_object_destroy(object);
} else {
llcache_size += total_object_size(object);
}
}
/* Stale cacheable objects with no users or pending fetches */
for (object = llcache->cached_objects;
object != NULL;
object = next) {
next = object->next;
remaining_lifetime = llcache_object_rfc2616_remaining_lifetime(
&object->cache);
if ((object->users == NULL) &&
(object->candidate_count == 0) &&
(object->fetch.fetch == NULL) &&
(remaining_lifetime <= 0)) {
/* object is stale */
NSLOG(llcache, DEBUG, "discarding stale cacheable object with no "
"users or pending fetches (%p) %s",
object, nsurl_access(object->url));
llcache_object_remove_from_list(object,
&llcache->cached_objects);
if (object->store_state == LLCACHE_STATE_DISC) {
guit->llcache->invalidate(object->url);
}
llcache_object_destroy(object);
} else {
/* object has users so account for the storage */
llcache_size += total_object_size(object);
}
}
/* if the cache limit is exceeded try to make some objects
* persistent so their RAM can be reclaimed in the next
* step
*/
if (limit < llcache_size) {
llcache_persist(NULL);
}
/* Source data of fresh cacheable objects with no users, no
* pending fetches and pushed to persistent store while the
* cache exceeds the configured size.
*/
for (object = llcache->cached_objects;
((limit < llcache_size) && (object != NULL));
object = next) {
next = object->next;
if ((object->users == NULL) &&
(object->candidate_count == 0) &&
(object->fetch.fetch == NULL) &&
(object->store_state == LLCACHE_STATE_DISC)) {
guit->llcache->release(object->url, BACKING_STORE_NONE);
object->source_data = NULL;
llcache_size -= object->source_len;
NSLOG(llcache, DEBUG,
"Freeing source data for %p len:%"PRIssizet,
object, object->source_len);
}
}
/* Fresh cacheable objects with no users, no pending fetches
* and pushed to persistent store while the cache exceeds
* the configured size. Effectively just the llcache object metadata.
*/
for (object = llcache->cached_objects;
((limit < llcache_size) && (object != NULL));
object = next) {
next = object->next;
if ((object->users == NULL) &&
(object->candidate_count == 0) &&
(object->fetch.fetch == NULL) &&
(object->store_state == LLCACHE_STATE_DISC) &&
(object->source_data == NULL)) {
NSLOG(llcache, DEBUG,
"discarding backed object len:%"PRIssizet" age:%ld (%p) %s",
object->source_len,
(long)(time(NULL) - object->last_used),
object,
nsurl_access(object->url));
llcache_size -= total_object_size(object);
llcache_object_remove_from_list(object,
&llcache->cached_objects);
llcache_object_destroy(object);
}
}
/* Fresh cacheable objects with no users or pending fetches
* while the cache exceeds the configured size. These are the
* most valuable objects as replacing them is a full network
* fetch
*/
for (object = llcache->cached_objects;
((limit < llcache_size) && (object != NULL));
object = next) {
next = object->next;
if ((object->users == NULL) &&
(object->candidate_count == 0) &&
(object->fetch.fetch == NULL) &&
(object->store_state == LLCACHE_STATE_RAM)) {
NSLOG(llcache, DEBUG,
"discarding fresh object len:%"PRIssizet" age:%ld (%p) %s",
object->source_len,
(long)(time(NULL) - object->last_used),
object,
nsurl_access(object->url));
llcache_size -= object->source_len + sizeof(*object);
llcache_object_remove_from_list(object,
&llcache->cached_objects);
llcache_object_destroy(object);
}
}
NSLOG(llcache, DEBUG, "Size: %u (limit: %u)", llcache_size, limit);
}
/* Exported interface documented in content/llcache.h */
nserror
llcache_initialise(const struct llcache_parameters *prm)
{
llcache = calloc(1, sizeof(struct llcache_s));
if (llcache == NULL) {
return NSERROR_NOMEM;
}
llcache->limit = prm->limit;
llcache->minimum_lifetime = prm->minimum_lifetime;
llcache->minimum_bandwidth = prm->minimum_bandwidth;
llcache->maximum_bandwidth = prm->maximum_bandwidth;
llcache->time_quantum = prm->time_quantum;
llcache->fetch_attempts = prm->fetch_attempts;
llcache->all_caught_up = true;
NSLOG(llcache, INFO,
"llcache initialising with a limit of %d bytes",
llcache->limit);
/* backing store initialisation */
return guit->llcache->initialise(&prm->store);
}
/* Exported interface documented in content/llcache.h */
void llcache_finalise(void)
{
llcache_object *object, *next;
uint64_t total_bandwidth = 0; /* total bandwidth */
/* Clean uncached objects */
for (object = llcache->uncached_objects; object != NULL; object = next) {
llcache_object_user *user, *next_user;
next = object->next;
for (user = object->users; user != NULL; user = next_user) {
next_user = user->next;
if (user->handle != NULL)
free(user->handle);
free(user);
}
/* Fetch system has already been destroyed */
object->fetch.fetch = NULL;
llcache_object_destroy(object);
}
/* Clean cached objects */
for (object = llcache->cached_objects; object != NULL; object = next) {
llcache_object_user *user, *next_user;
next = object->next;
for (user = object->users; user != NULL; user = next_user) {
next_user = user->next;
if (user->handle != NULL)
free(user->handle);
free(user);
}
/* Fetch system has already been destroyed */
object->fetch.fetch = NULL;
llcache_object_destroy(object);
}
/* backing store finalisation */
guit->llcache->finalise();
if (llcache->total_elapsed > 0) {
total_bandwidth = (llcache->total_written * 1000) /
llcache->total_elapsed;
}
NSLOG(llcache, INFO,
"Backing store wrote %"PRIu64" bytes in %"PRIu64" ms ""(average %"PRIu64" bytes/second)",
llcache->total_written,
llcache->total_elapsed,
total_bandwidth);
free(llcache);
llcache = NULL;
}
/**
* Catch up the cache users with state changes from fetchers.
*
* \param ignored We ignore this because all our state comes from llcache.
*/
static void llcache_catch_up_all_users(void *ignored)
{
llcache_object *object;
/* Assume after this we'll be all caught up. If any user of a handle
* defers then we'll invalidate all_caught_up and reschedule via
* llcache_users_not_caught_up()
*/
llcache->all_caught_up = true;
/* Catch new users up with state of objects */
for (object = llcache->cached_objects; object != NULL;
object = object->next) {
llcache_object_notify_users(object);
}
for (object = llcache->uncached_objects; object != NULL;
object = object->next) {
llcache_object_notify_users(object);
}
}
/**
* Ask for ::llcache_catch_up_all_users to be scheduled ASAP to pump the
* user state machines.
*/
static void llcache_users_not_caught_up(void)
{
if (llcache->all_caught_up) {
llcache->all_caught_up = false;
guit->misc->schedule(0, llcache_catch_up_all_users, NULL);
}
}
/* Exported interface documented in content/llcache.h */
nserror llcache_handle_retrieve(nsurl *url, uint32_t flags,
nsurl *referer, const llcache_post_data *post,
llcache_handle_callback cb, void *pw,
llcache_handle **result)
{
nserror error;
llcache_object_user *user;
llcache_object *object;
nsurl *hsts_url;
bool hsts_in_use;
/* Perform HSTS transform */
error = llcache_hsts_transform_url(url, &hsts_url, &hsts_in_use);
if (error != NSERROR_OK) {
return error;
}
/* Can we fetch this URL at all? */
if (fetch_can_fetch(hsts_url) == false) {
nsurl_unref(hsts_url);
return NSERROR_NO_FETCH_HANDLER;
}
/* Create a new object user */
error = llcache_object_user_new(cb, pw, &user);
if (error != NSERROR_OK) {
nsurl_unref(hsts_url);
return error;
}
/* Retrieve a suitable object from the cache,
* creating a new one if needed. */
error = llcache_object_retrieve(hsts_url, flags, referer, post, 0,
hsts_in_use, &object);
if (error != NSERROR_OK) {
llcache_object_user_destroy(user);
nsurl_unref(hsts_url);
return error;
}
/* Add user to object */
llcache_object_add_user(object, user);
*result = user->handle;
/* Users exist which are now not caught up! */
llcache_users_not_caught_up();
nsurl_unref(hsts_url);
return NSERROR_OK;
}
/* Exported interface documented in content/llcache.h */
nserror llcache_handle_change_callback(llcache_handle *handle,
llcache_handle_callback cb, void *pw)
{
handle->cb = cb;
handle->pw = pw;
return NSERROR_OK;
}
/* Exported interface documented in content/llcache.h */
nserror llcache_handle_release(llcache_handle *handle)
{
nserror error = NSERROR_OK;
llcache_object *object = handle->object;
llcache_object_user *user = llcache_object_find_user(handle);
assert(user != NULL);
if (user->iterator_target) {
/* Can't remove / delete user object if it's
* the target of an iterator */
user->queued_for_delete = true;
} else {
/* Remove the user from the object and destroy it */
error = llcache_object_remove_user(object, user);
if (error == NSERROR_OK) {
error = llcache_object_user_destroy(user);
}
}
return error;
}
/* Exported interface documented in content/llcache.h */
nserror llcache_handle_clone(llcache_handle *handle, llcache_handle **result)
{
nserror error;
llcache_object_user *newuser;
error = llcache_object_user_new(handle->cb, handle->pw, &newuser);
if (error == NSERROR_OK) {
llcache_object_add_user(handle->object, newuser);
newuser->handle->state = handle->state;
*result = newuser->handle;
}
return error;
}
/* See llcache.h for documentation */
nserror llcache_handle_abort(llcache_handle *handle)
{
llcache_object_user *user = llcache_object_find_user(handle);
llcache_object *object = handle->object, *newobject;
nserror error = NSERROR_OK;
bool all_alone = true;
/* Determine if we are the only user */
if (user->prev != NULL)
all_alone = false;
if (user->next != NULL)
all_alone = false;
if (all_alone == false) {
/* We must snapshot this object */
error = llcache_object_snapshot(object, &newobject);
if (error != NSERROR_OK)
return error;
/* Move across to the new object */
if (user->iterator_target) {
/* User is current iterator target, clone it */
llcache_object_user *newuser =
calloc(1, sizeof(llcache_object_user));
if (newuser == NULL) {
llcache_object_destroy(newobject);
return NSERROR_NOMEM;
}
/* Move handle across to clone */
newuser->handle = user->handle;
user->handle = NULL;
/* Mark user as needing deletion */
user->queued_for_delete = true;
llcache_object_add_user(newobject, newuser);
} else {
llcache_object_remove_user(object, user);
llcache_object_add_user(newobject, user);
}
/* Add new object to uncached list */
llcache_object_add_to_list(newobject,
&llcache->uncached_objects);
} else {
/* We're the only user, so abort any fetch in progress */
if (object->fetch.fetch != NULL) {
fetch_abort(object->fetch.fetch);
object->fetch.fetch = NULL;
}
object->fetch.state = LLCACHE_FETCH_COMPLETE;
/* Invalidate cache control data */
llcache_invalidate_cache_control_data(object);
}
return error;
}
/* See llcache.h for documentation */
nserror llcache_handle_force_stream(llcache_handle *handle)
{
llcache_object_user *user = llcache_object_find_user(handle);
llcache_object *object = handle->object;
/* Cannot stream if there are multiple users */
if (user->prev != NULL || user->next != NULL)
return NSERROR_OK;
/* Forcibly uncache this object */
if (llcache_object_in_list(object, llcache->cached_objects)) {
llcache_object_remove_from_list(object,
&llcache->cached_objects);
llcache_object_add_to_list(object, &llcache->uncached_objects);
}
object->fetch.flags |= LLCACHE_RETRIEVE_STREAM_DATA;
return NSERROR_OK;
}
/* See llcache.h for documentation */
nserror llcache_handle_invalidate_cache_data(llcache_handle *handle)
{
if ((handle->object != NULL) &&
(handle->object->fetch.fetch == NULL) &&
(handle->object->cache.no_cache == LLCACHE_VALIDATE_FRESH)) {
/* mark the cached object as requiring validation */
handle->object->cache.no_cache = LLCACHE_VALIDATE_ONCE;
}
return NSERROR_OK;
}
/* See llcache.h for documentation */
nsurl *llcache_handle_get_url(const llcache_handle *handle)
{
return handle->object != NULL ? handle->object->url : NULL;
}
/* See llcache.h for documentation */
const uint8_t *llcache_handle_get_source_data(const llcache_handle *handle,
size_t *size)
{
*size = handle->object != NULL ? handle->object->source_len : 0;
return handle->object != NULL ? handle->object->source_data : NULL;
}
/* See llcache.h for documentation */
const char *llcache_handle_get_header(const llcache_handle *handle,
const char *key)
{
const llcache_object *object = handle->object;
size_t i;
if (object == NULL)
return NULL;
/* About as trivial as possible */
for (i = 0; i < object->num_headers; i++) {
if (strcasecmp(key, object->headers[i].name) == 0)
return object->headers[i].value;
}
return NULL;
}
/* See llcache.h for documentation */
bool llcache_handle_references_same_object(const llcache_handle *a,
const llcache_handle *b)
{
return a->object == b->object;
}
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