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/*
* Copyright 2016 IoT.bzh
* Author: José Bollo <jose.bollo@iot.bzh>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define _GNU_SOURCE
#include <microhttpd.h>
#include <assert.h>
#include <poll.h>
#include <sys/stat.h>
#include "../include/local-def.h"
#include "afb-method.h"
#include "afb-req-itf.h"
#include "afb-hreq.h"
static char empty_string[1] = "";
/* a valid subpath is a relative path not looking deeper than root using .. */
static int validsubpath(const char *subpath)
{
int l = 0, i = 0;
while (subpath[i]) {
switch (subpath[i++]) {
case '.':
if (!subpath[i])
break;
if (subpath[i] == '/') {
i++;
break;
}
if (subpath[i++] == '.') {
if (!subpath[i]) {
if (--l < 0)
return 0;
break;
}
if (subpath[i++] == '/') {
if (--l < 0)
return 0;
break;
}
}
default:
while (subpath[i] && subpath[i] != '/')
i++;
l++;
case '/':
break;
}
}
return 1;
}
/*
* Removes the 'prefix' of 'length' frome the tail of 'hreq'
* if and only if the prefix exists and is terminated by a leading
* slash
*/
int afb_hreq_unprefix(struct afb_hreq *hreq, const char *prefix, size_t length)
{
/* check the prefix ? */
if (length > hreq->lentail || (hreq->tail[length] && hreq->tail[length] != '/')
|| memcmp(prefix, hreq->tail, length))
return 0;
/* removes successives / */
while (length < hreq->lentail && hreq->tail[length + 1] == '/')
length++;
/* update the tail */
hreq->lentail -= length;
hreq->tail += length;
return 1;
}
int afb_hreq_valid_tail(struct afb_hreq *hreq)
{
return validsubpath(hreq->tail);
}
void afb_hreq_reply_error(struct afb_hreq *hreq, unsigned int status)
{
char *buffer;
int length;
struct MHD_Response *response;
length = asprintf(&buffer, "<html><body>error %u</body></html>", status);
if (length > 0)
response = MHD_create_response_from_buffer((unsigned)length, buffer, MHD_RESPMEM_MUST_FREE);
else {
buffer = "<html><body>error</body></html>";
response = MHD_create_response_from_buffer(strlen(buffer), buffer, MHD_RESPMEM_PERSISTENT);
}
if (!MHD_queue_response(hreq->connection, status, response))
fprintf(stderr, "Failed to reply error code %u", status);
MHD_destroy_response(response);
}
int afb_hreq_reply_file_if_exist(struct afb_hreq *hreq, int dirfd, const char *filename)
{
int rc;
int fd;
unsigned int status;
struct stat st;
char etag[1 + 2 * sizeof(int)];
const char *inm;
struct MHD_Response *response;
/* Opens the file or directory */
fd = openat(dirfd, filename, O_RDONLY);
if (fd < 0) {
if (errno == ENOENT)
return 0;
afb_hreq_reply_error(hreq, MHD_HTTP_FORBIDDEN);
return 1;
}
/* Retrieves file's status */
if (fstat(fd, &st) != 0) {
close(fd);
afb_hreq_reply_error(hreq, MHD_HTTP_INTERNAL_SERVER_ERROR);
return 1;
}
/* serve directory */
if (S_ISDIR(st.st_mode)) {
if (hreq->url[hreq->lenurl - 1] != '/') {
/* the redirect is needed for reliability of relative path */
char *tourl = alloca(hreq->lenurl + 2);
memcpy(tourl, hreq->url, hreq->lenurl);
tourl[hreq->lenurl] = '/';
tourl[hreq->lenurl + 1] = 0;
rc = afb_hreq_redirect_to(hreq, tourl);
} else {
rc = afb_hreq_reply_file_if_exist(hreq, fd, "index.html");
}
close(fd);
return rc;
}
/* Don't serve special files */
if (!S_ISREG(st.st_mode)) {
close(fd);
afb_hreq_reply_error(hreq, MHD_HTTP_FORBIDDEN);
return 1;
}
/* Check the method */
if ((hreq->method & (afb_method_get | afb_method_head)) == 0) {
close(fd);
afb_hreq_reply_error(hreq, MHD_HTTP_METHOD_NOT_ALLOWED);
return 1;
}
/* computes the etag */
sprintf(etag, "%08X%08X", ((int)(st.st_mtim.tv_sec) ^ (int)(st.st_mtim.tv_nsec)), (int)(st.st_size));
/* checks the etag */
inm = MHD_lookup_connection_value(hreq->connection, MHD_HEADER_KIND, MHD_HTTP_HEADER_IF_NONE_MATCH);
if (inm && 0 == strcmp(inm, etag)) {
/* etag ok, return NOT MODIFIED */
close(fd);
if (verbose)
fprintf(stderr, "Not Modified: [%s]\n", filename);
response = MHD_create_response_from_buffer(0, empty_string, MHD_RESPMEM_PERSISTENT);
status = MHD_HTTP_NOT_MODIFIED;
} else {
/* check the size */
if (st.st_size != (off_t) (size_t) st.st_size) {
close(fd);
afb_hreq_reply_error(hreq, MHD_HTTP_INTERNAL_SERVER_ERROR);
return 1;
}
/* create the response */
response = MHD_create_response_from_fd((size_t) st.st_size, fd);
status = MHD_HTTP_OK;
#if defined(USE_MAGIC_MIME_TYPE)
/* set the type */
if (hreq->session->magic) {
const char *mimetype = magic_descriptor(hreq->session->magic, fd);
if (mimetype != NULL)
MHD_add_response_header(response, MHD_HTTP_HEADER_CONTENT_TYPE, mimetype);
}
#endif
}
/* fills the value and send */
MHD_add_response_header(response, MHD_HTTP_HEADER_CACHE_CONTROL, hreq->session->cacheTimeout);
MHD_add_response_header(response, MHD_HTTP_HEADER_ETAG, etag);
MHD_queue_response(hreq->connection, status, response);
MHD_destroy_response(response);
return 1;
}
int afb_hreq_reply_file(struct afb_hreq *hreq, int dirfd, const char *filename)
{
int rc = afb_hreq_reply_file_if_exist(hreq, dirfd, filename);
if (rc == 0)
afb_hreq_reply_error(hreq, MHD_HTTP_NOT_FOUND);
return 1;
}
int afb_hreq_redirect_to(struct afb_hreq *hreq, const char *url)
{
struct MHD_Response *response;
response = MHD_create_response_from_buffer(0, empty_string, MHD_RESPMEM_PERSISTENT);
MHD_add_response_header(response, MHD_HTTP_HEADER_LOCATION, url);
MHD_queue_response(hreq->connection, MHD_HTTP_MOVED_PERMANENTLY, response);
MHD_destroy_response(response);
if (verbose)
fprintf(stderr, "redirect from [%s] to [%s]\n", hreq->url, url);
return 1;
}
const char *afb_hreq_get_cookie(struct afb_hreq *hreq, const char *name)
{
return MHD_lookup_connection_value(hreq->connection, MHD_COOKIE_KIND, name);
}
const char *afb_hreq_get_argument(struct afb_hreq *hreq, const char *name)
{
return MHD_lookup_connection_value(hreq->connection, MHD_GET_ARGUMENT_KIND, name);
}
const char *afb_hreq_get_header(struct afb_hreq *hreq, const char *name)
{
return MHD_lookup_connection_value(hreq->connection, MHD_HEADER_KIND, name);
}
struct afb_req_itf afb_hreq_itf = {
.get_cookie = (void*)afb_hreq_get_cookie,
.get_argument = (void*)afb_hreq_get_argument
};
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