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httpdirfs
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httpdirfs/network.c

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#include "network.h"
#include <openssl/crypto.h>
#include <ctype.h>
#include <errno.h>
#include <pthread.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define HTTP_OK 200
#define HTTP_PARTIAL_CONTENT 206
#define HTTP_RANGE_NOT_SATISFIABLE 416
/* ------------------------ External variables ----------------------------*/
LinkTable *ROOT_LINK_TBL;
/* ------------------------ Local structs ---------------------------------*/
typedef struct {
char *memory;
size_t size;
} MemoryStruct;
typedef enum {
FILESTAT = 's',
DATA = 'd'
} TransferType;
typedef struct {
TransferType type;
int transferring;
Link *link;
} TransferStruct;
/* ------------------------ Static variable ------------------------------ */
/** \brief curl shared interface - not actually being used. */
static CURLSH *curl_share;
/** \brief curl multi interface handle */
static CURLM *curl_multi;
/** \brief pthread mutex for transfer functions */
static pthread_mutex_t transfer_lock;
/** \brief the lock array for cryptographic functions */
static pthread_mutex_t *crypto_lockarray;
/**
* \brief pthread mutex for curl itself
* \note I am sure if it is being used properly
*/
static pthread_mutex_t curl_lock;
/* -------------------------- Functions ---------------------------------- */
#pragma GCC diagnostic ignored "-Wunused-function"
static void lock_callback(int mode, int type, char *file, int line)
{
#pragma GCC diagnostic pop
(void)file;
(void)line;
if(mode & CRYPTO_LOCK) {
pthread_mutex_lock(&(crypto_lockarray[type]));
}
else {
pthread_mutex_unlock(&(crypto_lockarray[type]));
}
}
#pragma GCC diagnostic ignored "-Wunused-function"
static unsigned long thread_id(void)
{
#pragma GCC diagnostic pop
unsigned long ret;
ret = (unsigned long)pthread_self();
return ret;
}
static void init_locks(void)
{
int i;
crypto_lockarray = (pthread_mutex_t *)OPENSSL_malloc(CRYPTO_num_locks() *
sizeof(pthread_mutex_t));
for(i = 0; i<CRYPTO_num_locks(); i++) {
pthread_mutex_init(&(crypto_lockarray[i]), NULL);
}
CRYPTO_set_id_callback((unsigned long (*)())thread_id);
CRYPTO_set_locking_callback((void (*)())lock_callback);
}
static void pthread_lock_cb(CURL *handle, curl_lock_data data,
curl_lock_access access, void *userptr)
{
(void)access; /* unused */
(void)userptr; /* unused */
(void)handle; /* unused */
(void)data; /* unused */
pthread_mutex_lock(&curl_lock);
}
static void pthread_unlock_cb(CURL *handle, curl_lock_data data,
void *userptr)
{
(void)userptr; /* unused */
(void)handle; /* unused */
(void)data; /* unused */
pthread_mutex_unlock(&curl_lock);
}
void network_init(const char *url)
{
/*
* Intialise the cryptographic locks, these are shamelessly copied from
* https://curl.haxx.se/libcurl/c/threaded-ssl.html
*/
init_locks();
/* Global related */
if (curl_global_init(CURL_GLOBAL_ALL)) {
fprintf(stderr, "network_init(): curl_global_init() failed!\n");
exit(EXIT_FAILURE);
}
/* Share related */
curl_share = curl_share_init();
if (!(curl_share)) {
fprintf(stderr, "network_init(): curl_share_init() failed!\n");
exit(EXIT_FAILURE);
}
curl_share_setopt(curl_share, CURLSHOPT_SHARE, CURL_LOCK_DATA_COOKIE);
curl_share_setopt(curl_share, CURLSHOPT_SHARE, CURL_LOCK_DATA_DNS);
curl_share_setopt(curl_share, CURLSHOPT_SHARE, CURL_LOCK_DATA_CONNECT);
if (pthread_mutex_init(&curl_lock, NULL) != 0)
{
printf(
"network_init(): curl_lock initialisation failed!\n");
exit(EXIT_FAILURE);
}
curl_share_setopt(curl_share, CURLSHOPT_LOCKFUNC, pthread_lock_cb);
curl_share_setopt(curl_share, CURLSHOPT_UNLOCKFUNC, pthread_unlock_cb);
/* Multi related */
curl_multi = curl_multi_init();
if (!curl_multi) {
fprintf(stderr, "network_init(): curl_multi_init() failed!\n");
exit(EXIT_FAILURE);
}
curl_multi_setopt(curl_multi, CURLMOPT_MAXCONNECTS,
CURL_MULTI_MAX_CONNECTION);
/* Initialise transfer lock */
if (pthread_mutex_init(&transfer_lock, NULL) != 0)
{
printf(
"network_init(): transfer_lock initialisation failed!\n");
exit(EXIT_FAILURE);
}
curl_version_info_data *data = curl_version_info(CURLVERSION_NOW);
printf("libcurl SSL engine: %s\n", data->ssl_version);
/* create the root link table */
ROOT_LINK_TBL = LinkTable_new(url);
}
static void link_set_stat(Link* this_link, CURL *curl)
{
long http_resp;
curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &http_resp);
if (http_resp == HTTP_OK) {
double cl = 0;
curl_easy_getinfo(curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &cl);
curl_easy_getinfo(curl, CURLINFO_FILETIME, &(this_link->time));
if (cl == -1) {
/* Turns out not to be a file after all */
this_link->content_length = 0;
this_link->type = LINK_DIR;
} else {
this_link->content_length = cl;
this_link->type = LINK_FILE;
}
} else {
this_link->type = LINK_INVALID;
}
}
/**
* Shamelessly copy and pasted from:
* https://curl.haxx.se/libcurl/c/10-at-a-time.html
*/
static int curl_multi_perform_once()
{
pthread_mutex_lock(&transfer_lock);
/* Get curl multi interface to perform pending tasks */
int n_running_curl;
curl_multi_perform(curl_multi, &n_running_curl);
/* Check if any of the tasks encountered error */
int max_fd;
fd_set read_fd_set;
fd_set write_fd_set;
fd_set exc_fd_set;
FD_ZERO(&read_fd_set);
FD_ZERO(&write_fd_set);
FD_ZERO(&exc_fd_set);
CURLMcode res;
res = curl_multi_fdset(curl_multi, &read_fd_set, &write_fd_set, &exc_fd_set,
&max_fd);
if(res > 0) {
fprintf(stderr, "curl_multi_perform_once(): curl_multi_fdset: %d, %s\n",
res, curl_multi_strerror(res));
exit(EXIT_FAILURE);
}
long timeout;
if(curl_multi_timeout(curl_multi, &timeout)) {
fprintf(stderr, "curl_multi_perform_once(): curl_multi_timeout\n");
exit(EXIT_FAILURE);
}
if(timeout == -1) {
timeout = 100;
}
if(max_fd == -1) {
sleep((unsigned int)timeout / 1000);
} else {
struct timeval t;
t.tv_sec = timeout/1000;
t.tv_usec = (timeout%1000)*1000;
if(select(max_fd + 1, &read_fd_set, &write_fd_set,
&exc_fd_set, &t) < 0) {
fprintf(stderr,
"curl_multi_perform_once(): select(%i,,,,%li): %i: %s\n",
max_fd + 1, timeout, errno, strerror(errno));
exit(EXIT_FAILURE);
}
}
/* Process messages */
int n_mesgs;
CURLMsg *curl_msg;
while((curl_msg = curl_multi_info_read(curl_multi, &n_mesgs))) {
if (curl_msg->msg == CURLMSG_DONE) {
TransferStruct *transfer;
CURL *curl = curl_msg->easy_handle;
curl_easy_getinfo(curl_msg->easy_handle, CURLINFO_PRIVATE,
&transfer);
transfer->transferring = 0;
char *url = NULL;
if (curl_msg->data.result) {
curl_easy_getinfo(curl, CURLINFO_EFFECTIVE_URL, url);
fprintf(stderr,
"curl_multi_perform_once(): %d - %s <%s>\n",
curl_msg->data.result,
curl_easy_strerror(curl_msg->data.result),
url);
} else {
/* Transfer successful, query the file size */
if (transfer->type == FILESTAT) {
link_set_stat(transfer->link, curl);
}
}
curl_multi_remove_handle(curl_multi, curl);
/* clean up the handle, if we are querying the file size */
if (transfer->type == FILESTAT) {
curl_easy_cleanup(curl);
free(transfer);
}
} else {
fprintf(stderr, "curl_multi_perform_once(): curl_msg->msg: %d\n",
curl_msg->msg);
}
}
pthread_mutex_unlock(&transfer_lock);
return n_running_curl;
}
static void nonblocking_transfer(CURL *curl)
{
pthread_mutex_lock(&transfer_lock);
CURLMcode res = curl_multi_add_handle(curl_multi, curl);
pthread_mutex_unlock(&transfer_lock);
if(res > 0) {
fprintf(stderr, "blocking_multi_transfer(): %d, %s\n",
res, curl_multi_strerror(res));
exit(EXIT_FAILURE);
}
}
/* This uses the curl multi interface */
static void blocking_transfer(CURL *curl)
{
TransferStruct transfer;
transfer.type = DATA;
transfer.transferring = 1;
curl_easy_setopt(curl, CURLOPT_PRIVATE, &transfer);
pthread_mutex_lock(&transfer_lock);
CURLMcode res = curl_multi_add_handle(curl_multi, curl);
pthread_mutex_unlock(&transfer_lock);
if(res > 0) {
fprintf(stderr, "blocking_multi_transfer(): %d, %s\n",
res, curl_multi_strerror(res));
exit(EXIT_FAILURE);
}
while (transfer.transferring) {
curl_multi_perform_once();
}
}
static char *url_append(const char *url, const char *sublink)
{
int needs_separator = 0;
if (url[strlen(url)-1] != '/') {
needs_separator = 1;
}
char *str;
size_t ul = strlen(url);
size_t sl = strlen(sublink);
str = calloc(ul + sl + needs_separator + 1, sizeof(char));
if (!str) {
fprintf(stderr, "url_append(): calloc failure!\n");
exit(EXIT_FAILURE);
}
strncpy(str, url, ul);
if (needs_separator) {
str[ul] = '/';
}
strncat(str, sublink, sl);
return str;
}
static size_t
WriteMemoryCallback(void *contents, size_t size, size_t nmemb, void *userp)
{
size_t realsize = size * nmemb;
MemoryStruct *mem = (MemoryStruct *)userp;
mem->memory = realloc(mem->memory, mem->size + realsize + 1);
if(!mem->memory) {
/* out of memory! */
fprintf(stderr, "WriteMemoryCallback(): realloc failure!\n");
exit(EXIT_FAILURE);
return 0;
}
memmove(&(mem->memory[mem->size]), contents, realsize);
mem->size += realsize;
mem->memory[mem->size] = 0;
return realsize;
}
static Link *Link_new(const char *p_url, LinkType type)
{
Link *link = calloc(1, sizeof(Link));
if (!link) {
fprintf(stderr, "Link_new(): calloc failure!\n");
exit(EXIT_FAILURE);
}
strncpy(link->p_url, p_url, LINK_LEN_MAX);
link->type = type;
/* remove the '/' from p_url if it exists */
char *c = &(link->p_url[strnlen(link->p_url, LINK_LEN_MAX) - 1]);
if ( *c == '/') {
*c = '\0';
}
return link;
}
static CURL *Link_to_curl(Link *link)
{
CURL *curl = curl_easy_init();
if (!curl) {
fprintf(stderr, "Link_to_curl(): curl_easy_init() failed!\n");
}
/* set up some basic curl stuff */
curl_easy_setopt(curl, CURLOPT_USERAGENT, "mount-http-dir/libcurl");
curl_easy_setopt(curl, CURLOPT_VERBOSE, 0);
curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
/* for following directories without the '/' */
curl_easy_setopt(curl, CURLOPT_MAXREDIRS, 2);
curl_easy_setopt(curl, CURLOPT_URL, link->f_url);
curl_easy_setopt(curl, CURLOPT_TCP_KEEPALIVE, 1);
curl_easy_setopt(curl, CURLOPT_SHARE, curl_share);
/*
* The write back function pointer has to be set at curl handle creation,
* for thread safety
*/
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
return curl;
}
long path_download(const char *path, char *output_buf, size_t size,
off_t offset)
{
Link *link;
link = path_to_Link(path);
if (!link) {
return -ENOENT;
}
size_t start = offset;
size_t end = start + size;
char range_str[64];
snprintf(range_str, sizeof(range_str), "%lu-%lu", start, end);
MemoryStruct buf;
buf.size = 0;
buf.memory = NULL;
#ifdef HTTPDIRFS_INFO
fprintf(stderr, "path_download(%s, %p, %s);\n",
path, output_buf, range_str);
#endif
CURL *curl = Link_to_curl(link);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&buf);
curl_easy_setopt(curl, CURLOPT_RANGE, range_str);
blocking_transfer(curl);
long http_resp;
curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &http_resp);
if ( !(
(http_resp != HTTP_OK) ||
(http_resp != HTTP_PARTIAL_CONTENT) ||
(http_resp != HTTP_RANGE_NOT_SATISFIABLE)
)) {
fprintf(stderr, "path_download(): Could not download %s, HTTP %ld\n",
link->f_url, http_resp);
return -ENOENT;
}
double dl;
curl_easy_getinfo(curl, CURLINFO_SIZE_DOWNLOAD, &dl);
size_t recv = dl;
if (recv > size) {
recv = size;
}
memmove(output_buf, buf.memory, recv);
curl_easy_cleanup(curl);
free(buf.memory);
return recv;
}
static void LinkTable_free(LinkTable *linktbl)
{
for (int i = 0; i < linktbl->num; i++) {
free(linktbl->links[i]);
}
free(linktbl->links);
free(linktbl);
}
static LinkType p_url_type(const char *p_url)
{
/* The link name has to start with alphanumerical character */
if (!isalnum(p_url[0])) {
return LINK_INVALID;
}
/* check for http:// and https:// */
if ( !strncmp(p_url, "http://", 7) || !strncmp(p_url, "https://", 8) ) {
return LINK_INVALID;
}
if ( p_url[strlen(p_url) - 1] == '/' ) {
return LINK_DIR;
}
return LINK_FILE;
}
static void LinkTable_add(LinkTable *linktbl, Link *link)
{
linktbl->num++;
linktbl->links = realloc(linktbl->links, linktbl->num * sizeof(Link *));
if (!linktbl->links) {
fprintf(stderr, "LinkTable_add(): realloc failure!\n");
exit(EXIT_FAILURE);
}
linktbl->links[linktbl->num - 1] = link;
}
/**
* Shamelessly copied and pasted from:
* https://github.com/google/gumbo-parser/blob/master/examples/find_links.cc
*/
static void HTML_to_LinkTable(GumboNode *node, LinkTable *linktbl)
{
if (node->type != GUMBO_NODE_ELEMENT) {
return;
}
GumboAttribute* href;
if (node->v.element.tag == GUMBO_TAG_A &&
(href = gumbo_get_attribute(&node->v.element.attributes, "href"))) {
/* if it is valid, copy the link onto the heap */
LinkType type = p_url_type(href->value);
if (type) {
LinkTable_add(linktbl, Link_new(href->value, type));
}
}
/* Note the recursive call, lol. */
GumboVector *children = &node->v.element.children;
for (size_t i = 0; i < children->length; ++i) {
HTML_to_LinkTable((GumboNode*)children->data[i], linktbl);
}
return;
}
void Link_get_stat(Link *this_link)
{
#ifdef HTTPDIRFS_INFO
fprintf(stderr, "Link_get_size(%s);\n", this_link->f_url);
#endif
if (this_link->type == LINK_FILE) {
CURL *curl = Link_to_curl(this_link);
curl_easy_setopt(curl, CURLOPT_NOBODY, 1);
curl_easy_setopt(curl, CURLOPT_FILETIME, 1L);
TransferStruct *transfer = malloc(sizeof(TransferStruct));
if (!transfer) {
fprintf(stderr, "Link_get_size(): malloc failed!\n");
}
transfer->link = this_link;
transfer->type = FILESTAT;
curl_easy_setopt(curl, CURLOPT_PRIVATE, transfer);
nonblocking_transfer(curl);
}
}
void LinkTable_fill(LinkTable *linktbl)
{
Link *head_link = linktbl->links[0];
for (int i = 0; i < linktbl->num; i++) {
Link *this_link = linktbl->links[i];
if (this_link->type) {
char *url;
url = url_append(head_link->f_url, this_link->p_url);
strncpy(this_link->f_url, url, URL_LEN_MAX);
free(url);
char *unescaped_p_url;
unescaped_p_url = curl_easy_unescape(NULL, this_link->p_url, 0,
NULL);
strncpy(this_link->p_url, unescaped_p_url, LINK_LEN_MAX);
curl_free(unescaped_p_url);
if (this_link->type == LINK_FILE && !(this_link->content_length)) {
Link_get_stat(this_link);
}
}
}
/* Block until the LinkTable is filled up */
while(curl_multi_perform_once());
}
LinkTable *LinkTable_new(const char *url)
{
#ifdef HTTPDIRFS_INFO
fprintf(stderr, "LinkTable_new(%s);\n", url);
#endif
LinkTable *linktbl = calloc(1, sizeof(LinkTable));
if (!linktbl) {
fprintf(stderr, "LinkTable_new(): calloc failure!\n");
exit(EXIT_FAILURE);
}
/* populate the base URL */
LinkTable_add(linktbl, Link_new("/", LINK_HEAD));
Link *head_link = linktbl->links[0];
head_link->type = LINK_HEAD;
strncpy(head_link->f_url, url, URL_LEN_MAX);
/* start downloading the base URL */
CURL *curl = Link_to_curl(head_link);
MemoryStruct buf;
buf.size = 0;
buf.memory = NULL;
// curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&buf);
blocking_transfer(curl);
/* if downloading base URL failed */
long http_resp;
curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &http_resp);
if (http_resp != HTTP_OK) {
fprintf(stderr, "link.c: LinkTable_new() cannot retrive the base URL, \
URL: %s, HTTP %ld\n", url, http_resp);
LinkTable_free(linktbl);
linktbl = NULL;
return linktbl;
};
curl_easy_cleanup(curl);
/* Otherwise parsed the received data */
GumboOutput* output = gumbo_parse(buf.memory);
HTML_to_LinkTable(output->root, linktbl);
gumbo_destroy_output(&kGumboDefaultOptions, output);
free(buf.memory);
/* Fill in the link table */
LinkTable_fill(linktbl);
return linktbl;
}
#ifdef HTTPDIRFS_INFO
void LinkTable_print(LinkTable *linktbl)
{
fprintf(stderr, "--------------------------------------------\n");
fprintf(stderr, " LinkTable %p for %s\n", linktbl,
linktbl->links[0]->f_url);
fprintf(stderr, "--------------------------------------------\n");
for (int i = 0; i < linktbl->num; i++) {
Link *this_link = linktbl->links[i];
fprintf(stderr, "%d %c %lu %s %p %s\n",
i,
this_link->type,
this_link->content_length,
this_link->p_url,
this_link->next_table,
this_link->f_url
);
}
fprintf(stderr, "--------------------------------------------\n");
}
#endif
static Link *path_to_Link_recursive(char *path, LinkTable *linktbl)
{
/* skip the leading '/' if it exists */
if (*path == '/') {
path++;
}
/* remove the last '/' if it exists */
char *slash = &(path[strnlen(path, URL_LEN_MAX) - 1]);
if (*slash == '/') {
*slash = '\0';
}
slash = strchr(path, '/');
if ( slash == NULL ) {
/* We cannot find another '/', we have reached the last level */
for (int i = 1; i < linktbl->num; i++) {
if (!strncmp(path, linktbl->links[i]->p_url, LINK_LEN_MAX)) {
/* We found our link */
return linktbl->links[i];
}
}
} else {
/*
* We can still find '/', time to consume the path and traverse
* the tree structure
*/
/*
* add termination mark to the current string,
* effective create two substrings
*/
*slash = '\0';
/* move the pointer past the '/' */
char *next_path = slash + 1;
for (int i = 1; i < linktbl->num; i++) {
if (!strncmp(path, linktbl->links[i]->p_url, LINK_LEN_MAX)) {
/* The next sub-directory exists */
if (!(linktbl->links[i]->next_table)) {
linktbl->links[i]->next_table = LinkTable_new(
linktbl->links[i]->f_url);
#ifdef HTTPDIRFS_INFO
fprintf(stderr, "Created new link table for %s\n",
linktbl->links[i]->f_url);
LinkTable_print(linktbl->links[i]->next_table);
#endif
}
return path_to_Link_recursive(next_path,
linktbl->links[i]->next_table);
}
}
}
return NULL;
}
Link *path_to_Link(const char *path)
{
char *new_path = strndup(path, URL_LEN_MAX);
if (!new_path) {
fprintf(stderr, "path_to_Link(): cannot allocate memory\n");
exit(EXIT_FAILURE);
}
return path_to_Link_recursive(new_path, ROOT_LINK_TBL);
}
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