439 lines
12 KiB
C
439 lines
12 KiB
C
#include "network.h"
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#include <ctype.h>
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#include <errno.h>
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#include <string.h>
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#include <stdio.h>
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#include <stdlib.h>
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#define HTTP_OK 200
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#define HTTP_PARTIAL_CONTENT 206
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LinkTable *ROOT_LINK_TBL;
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/* ------------------------ Static variable ------------------------------ */
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/** \brief curl shared interface - not actually being used. */
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static CURLSH *curl_share;
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/* Forward declarations */
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static void HTML_to_LinkTable(GumboNode *node, LinkTable *linktbl);
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static LinkType p_url_type(const char *p_url);
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static void Link_free(Link *link);
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static Link *Link_new(const char *p_url, LinkType type);
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static CURL *Link_to_curl(Link *link);
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static void LinkTable_free(LinkTable *linktbl);
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static void LinkTable_add(LinkTable *linktbl, Link *link);
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static void LinkTable_fill(LinkTable *linktbl);
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static Link *path_to_Link_recursive(char *path, LinkTable *linktbl);
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static char *url_append(const char *url, const char *sublink);
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static size_t WriteMemoryCallback(void *contents, size_t size, size_t nmemb,
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void *userp);
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static void do_transfer(CURL *curl);
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/**
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* \brief convert a HTML page to a LinkTable
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* \details Shamelessly copied and pasted from:
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* https://github.com/google/gumbo-parser/blob/master/examples/find_links.cc
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*/
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static void HTML_to_LinkTable(GumboNode *node, LinkTable *linktbl);
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/* -------------------------- Functions ---------------------------------- */
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void network_init(const char *url)
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{
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curl_global_init(CURL_GLOBAL_ALL);
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ROOT_LINK_TBL = LinkTable_new(url);
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curl_share = curl_share_init();
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curl_share_setopt(curl_share, CURLSHOPT_SHARE, CURL_LOCK_DATA_COOKIE);
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curl_share_setopt(curl_share, CURLSHOPT_SHARE, CURL_LOCK_DATA_DNS);
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curl_share_setopt(curl_share, CURLSHOPT_SHARE, CURL_LOCK_DATA_CONNECT);
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}
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static CURL *Link_to_curl(Link *link)
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{
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#ifdef HTTPDIRFS_INFO
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fprintf(stderr, "Link_to_curl(): %s\n", link->f_url);
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fflush(stderr);
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#endif
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CURL *curl = curl_easy_init();
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/* set up some basic curl stuff */
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curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
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curl_easy_setopt(curl, CURLOPT_USERAGENT, "mount-http-dir/libcurl");
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curl_easy_setopt(curl, CURLOPT_VERBOSE, 0);
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curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
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/*
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* only 1 redirection is really needed
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* - for following directories without the '/'
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*/
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curl_easy_setopt(curl, CURLOPT_MAXREDIRS, 1);
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curl_easy_setopt(curl, CURLOPT_URL, link->f_url);
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curl_easy_setopt(curl, CURLOPT_TCP_KEEPALIVE, 1);
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curl_easy_setopt(curl, CURLOPT_SHARE, curl_share);
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return curl;
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}
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static char *url_append(const char *url, const char *sublink)
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{
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int needs_separator = 0;
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if (url[strlen(url)-1] != '/') {
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needs_separator = 1;
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}
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char *str;
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size_t ul = strlen(url);
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size_t sl = strlen(sublink);
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str = calloc(ul + sl + needs_separator + 1, sizeof(char));
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strncpy(str, url, ul);
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if (needs_separator) {
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str[ul] = '/';
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}
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strncat(str, sublink, sl);
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return str;
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}
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/* This is the single thread version */
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static void do_transfer(CURL *curl)
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{
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#ifdef HTTPDIRFS_DEBUG
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#pragma GCC diagnostic ignored "-Wformat"
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fprintf(stderr, "do_transfer(): handle %x\n", curl);
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fflush(stderr);
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#endif
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CURLcode res = curl_easy_perform(curl);
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if (res) {
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fprintf(stderr, "do_transfer() failed: %u, %s\n", res,
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curl_easy_strerror(res));
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fflush(stderr);
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}
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#ifdef HTTPDIRFS_DEBUG
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fprintf(stderr, "do_transfer(): DONE\n");
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fflush(stderr);
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#endif
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}
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static size_t
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WriteMemoryCallback(void *contents, size_t size, size_t nmemb, void *userp)
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{
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size_t realsize = size * nmemb;
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struct MemoryStruct *mem = (struct MemoryStruct *)userp;
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mem->memory = realloc(mem->memory, mem->size + realsize + 1);
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if(mem->memory == NULL) {
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/* out of memory! */
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fprintf(stderr, "WriteMemoryCallback(): cannot realloc!\n");
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fflush(stderr);
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return 0;
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}
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memmove(&(mem->memory[mem->size]), contents, realsize);
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mem->size += realsize;
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mem->memory[mem->size] = 0;
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return realsize;
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}
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static Link *Link_new(const char *p_url, LinkType type)
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{
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Link *link = calloc(1, sizeof(Link));
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strncpy(link->p_url, p_url, LINK_LEN_MAX);
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link->type = type;
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/* remove the '/' from p_url if it exists */
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char *c = &(link->p_url[strnlen(link->p_url, LINK_LEN_MAX) - 1]);
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if ( *c == '/') {
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*c = '\0';
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}
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return link;
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}
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static void Link_free(Link *link)
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{
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free(link);
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link = NULL;
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}
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long Link_download(const char *path, char *output_buf, size_t size,
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off_t offset)
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{
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Link *link;
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link = path_to_Link(path);
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if (!link) {
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return -ENOENT;
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}
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size_t start = offset;
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size_t end = start + size;
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CURL *curl = Link_to_curl(link);
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char range_str[64];
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snprintf(range_str, sizeof(range_str), "%lu-%lu", start, end);
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MemoryStruct buf;
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buf.size = 0;
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buf.memory = NULL;
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curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&buf);
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curl_easy_setopt(curl, CURLOPT_RANGE, range_str);
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do_transfer(curl);
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long http_resp;
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curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &http_resp);
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if ( (http_resp != HTTP_OK) && ( http_resp != HTTP_PARTIAL_CONTENT) ) {
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fprintf(stderr, "Link_download(): Could not download %s, HTTP %ld\n",
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link->f_url, http_resp);
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fflush(stderr);
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return -ENOENT;
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}
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double dl;
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curl_easy_getinfo(curl, CURLINFO_SIZE_DOWNLOAD, &dl);
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size_t recv = dl;
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if (recv > size) {
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recv = size;
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}
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memmove(output_buf, buf.memory, recv);
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curl_easy_cleanup(curl);
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free(buf.memory);
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return recv;
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}
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LinkTable *LinkTable_new(const char *url)
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{
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LinkTable *linktbl = calloc(1, sizeof(LinkTable));
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/* populate the base URL */
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LinkTable_add(linktbl, Link_new("/", LINK_HEAD));
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Link *head_link = linktbl->links[0];
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head_link->type = LINK_HEAD;
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strncpy(head_link->f_url, url, URL_LEN_MAX);
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/* start downloading the base URL */
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CURL *curl = Link_to_curl(head_link);
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MemoryStruct buf;
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buf.size = 0;
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buf.memory = NULL;
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curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&buf);
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do_transfer(curl);
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/* if downloading base URL failed */
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long http_resp;
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curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &http_resp);
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if (http_resp != HTTP_OK) {
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fprintf(stderr, "link.c: LinkTable_new() cannot retrive the base URL, \
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URL: %s, HTTP %ld\n", url, http_resp);
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fflush(stderr);
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LinkTable_free(linktbl);
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linktbl = NULL;
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return linktbl;
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};
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curl_easy_cleanup(curl);
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/* Otherwise parsed the received data */
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GumboOutput* output = gumbo_parse(buf.memory);
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HTML_to_LinkTable(output->root, linktbl);
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gumbo_destroy_output(&kGumboDefaultOptions, output);
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free(buf.memory);
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/* Fill in the link table */
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LinkTable_fill(linktbl);
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#ifdef HTTPDIRFS_INFO
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LinkTable_print(linktbl);
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#endif
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return linktbl;
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}
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static void LinkTable_free(LinkTable *linktbl)
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{
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for (int i = 0; i < linktbl->num; i++) {
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Link_free(linktbl->links[i]);
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}
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free(linktbl->links);
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free(linktbl);
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linktbl = NULL;
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}
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static void LinkTable_add(LinkTable *linktbl, Link *link)
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{
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linktbl->num++;
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linktbl->links = realloc(
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linktbl->links,
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linktbl->num * sizeof(Link *));
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linktbl->links[linktbl->num - 1] = link;
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}
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size_t Link_get_size(Link *this_link)
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{
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double cl = 0;
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if (this_link->type == LINK_FILE) {
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CURL *curl = Link_to_curl(this_link);
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curl_easy_setopt(curl, CURLOPT_NOBODY, 1);
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do_transfer(curl);
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long http_resp;
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curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &http_resp);
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if (http_resp == HTTP_OK) {
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curl_easy_getinfo(curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &cl);
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if (cl == -1) {
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/* Turns out not to be a file after all */
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this_link->content_length = 0;
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this_link->type = LINK_DIR;
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} else {
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this_link->content_length = cl;
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this_link->type = LINK_FILE;
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}
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} else {
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this_link->type = LINK_INVALID;
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}
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curl_easy_cleanup(curl);
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}
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return cl;
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}
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void LinkTable_fill(LinkTable *linktbl)
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{
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Link *head_link = linktbl->links[0];
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for (int i = 0; i < linktbl->num; i++) {
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Link *this_link = linktbl->links[i];
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if (this_link->type) {
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char *url;
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url = url_append(head_link->f_url, this_link->p_url);
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strncpy(this_link->f_url, url, URL_LEN_MAX);
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free(url);
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if (this_link->type == LINK_FILE) {
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this_link->content_length = Link_get_size(this_link);
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}
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}
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}
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}
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#ifdef HTTPDIRFS_INFO
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void LinkTable_print(LinkTable *linktbl)
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{
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for (int i = 0; i < linktbl->num; i++) {
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Link *this_link = linktbl->links[i];
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fprintf(stderr, "%d %c %lu %s %s\n",
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i,
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this_link->type,
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this_link->content_length,
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this_link->p_url,
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this_link->f_url
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);
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fflush(stderr);
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}
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}
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#endif
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static LinkType p_url_type(const char *p_url)
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{
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/* The link name has to start with alphanumerical character */
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if (!isalnum(p_url[0])) {
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return LINK_INVALID;
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}
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/* check for http:// and https:// */
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if ( !strncmp(p_url, "http://", 7) || !strncmp(p_url, "https://", 8) ) {
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return LINK_INVALID;
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}
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if ( p_url[strlen(p_url) - 1] == '/' ) {
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return LINK_DIR;
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}
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return LINK_FILE;
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}
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static void HTML_to_LinkTable(GumboNode *node, LinkTable *linktbl)
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{
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if (node->type != GUMBO_NODE_ELEMENT) {
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return;
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}
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GumboAttribute* href;
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if (node->v.element.tag == GUMBO_TAG_A &&
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(href = gumbo_get_attribute(&node->v.element.attributes, "href"))) {
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/* if it is valid, copy the link onto the heap */
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LinkType type = p_url_type(href->value);
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if (type) {
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LinkTable_add(linktbl, Link_new(href->value, type));
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}
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}
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/* Note the recursive call, lol. */
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GumboVector *children = &node->v.element.children;
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for (size_t i = 0; i < children->length; ++i) {
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HTML_to_LinkTable((GumboNode*)children->data[i], linktbl);
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}
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return;
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}
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static Link *path_to_Link_recursive(char *path, LinkTable *linktbl)
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{
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/* skip the leading '/' if it exists */
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if (*path == '/') {
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path++;
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}
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/* remove the last '/' if it exists */
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char *slash = &(path[strnlen(path, URL_LEN_MAX) - 1]);
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if (*slash == '/') {
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*slash = '\0';
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}
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slash = strchr(path, '/');
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if ( slash == NULL ) {
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/* We cannot find another '/', we have reached the last level */
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for (int i = 1; i < linktbl->num; i++) {
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if (!strncmp(path, linktbl->links[i]->p_url, LINK_LEN_MAX)) {
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/* We found our link */
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return linktbl->links[i];
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}
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}
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} else {
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/*
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* We can still find '/', time to consume the path and traverse
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* the tree structure
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*/
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/*
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* add termination mark to the current string,
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* effective create two substrings
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*/
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*slash = '\0';
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/* move the pointer past the '/' */
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char *next_path = slash + 1;
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for (int i = 1; i < linktbl->num; i++) {
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if (!strncmp(path, linktbl->links[i]->p_url, LINK_LEN_MAX)) {
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/* The next sub-directory exists */
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LinkTable *next_table = linktbl->links[i]->next_table;
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if (!(next_table)) {
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next_table = LinkTable_new(linktbl->links[i]->f_url);
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}
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return path_to_Link_recursive(next_path, next_table);
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}
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}
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}
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#ifdef HTTPDIRFS_DEBUG
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fprintf(stderr, "path_to_Link(): %s does not exist.\n", path);
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fflush(stderr);
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#endif
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return NULL;
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}
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Link *path_to_Link(const char *path)
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{
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char *new_path = strndup(path, URL_LEN_MAX);
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return path_to_Link_recursive(new_path, ROOT_LINK_TBL);
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}
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