vfs_http.c

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/*
 * Copyright (c) 2006-2009 Ed Schouten <ed@80386.nl>
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
#include "stdinc.h"

#include <curl/curl.h>
#include <curl/easy.h>
#include <curl/multi.h>

#include "gui.h"
#include "vfs.h"
#include "vfs_modules.h"

struct httpstream {
        char    *url;
        CURL    *con;
        CURLM   *conm;

        char    *bufptr;
        char    *buflen;
        char    buf[CURL_MAX_WRITE_SIZE];
};

static size_t
vfs_http_incoming(void *ptr, size_t size, size_t nmemb, void *cookie)
{
        struct httpstream *hs = cookie;
        size_t len;

        /* We just assume the buffer is completely drained */
        len = size * nmemb;
        memcpy(hs->buf, ptr, size * nmemb);
        hs->bufptr = hs->buf;
        hs->buflen = hs->buf + len;

        return (len);
}

#ifdef __GLIBC__
static ssize_t
vfs_http_readfn(void *cookie, char *buf, size_t len)
#else /* !__GLIBC__ */
static int
vfs_http_readfn(void *cookie, char *buf, int len)
#endif /* __GLIBC__ */
{
        struct httpstream *hs = cookie;
        struct timeval timeout = { 5, 0 };
        char *errmsg;
        int handles, left = len, copylen, maxfd, sret;
        fd_set rfds, wfds, efds;
        CURLMcode cret;

        while (left > 0) {
                if (hs->bufptr == hs->buflen) {
                        FD_ZERO(&rfds);
                        FD_ZERO(&wfds);
                        FD_ZERO(&efds);
                        curl_multi_fdset(hs->conm, &rfds, &wfds, &efds,
                            &maxfd);
                        if (maxfd != -1) {
                                /* Wait for data to arrive */
                                sret = select(maxfd + 1, &rfds, &wfds,
                                    &efds, &timeout);
                                if (sret <= 0)
                                        goto bad;
                        }
                        /* Fetch data from socket */
                        cret = curl_multi_perform(hs->conm, &handles);
                        if (handles == 0)
                                goto bad;
                        if (cret == CURLM_CALL_MULTI_PERFORM ||
                            hs->bufptr == hs->buflen)
                                continue;
                        if (cret != CURLM_OK)
                                goto bad;
                }

                /* Perform a copyout of the buffer */
                copylen = MIN(left, hs->buflen - hs->bufptr);
                memcpy(buf, hs->bufptr, copylen);
                left -= copylen;
                hs->bufptr += copylen;
                buf += copylen;
        }

        return (len);

bad:    /* Bail out with an error message */
        errmsg = g_strdup_printf(
            _("Connection with \"%s\" lost."), hs->url);
        gui_msgbar_warn(errmsg);
        g_free(errmsg);
        return (0);
}

static int
vfs_http_closefn(void *cookie)
{
        struct httpstream *hs = cookie;

        curl_multi_cleanup(hs->conm);
        curl_easy_cleanup(hs->con);
        g_free(hs->url);
        g_slice_free(struct httpstream, hs);

        return (0);
}

/*
 * Public interface
 */

int
vfs_http_match(struct vfsent *ve, int isdir)
{
        return strncmp(ve->filename, "http://", 7);
}

FILE *
vfs_http_open(struct vfsent *ve)
{
        struct httpstream *hs;
        FILE *ret;
#ifdef __GLIBC__
        cookie_io_functions_t iofn = {
            vfs_http_readfn, NULL, NULL, vfs_http_closefn };
#endif /* __GLIBC__ */

        /* Allocate the datastructure */
        hs = g_slice_new(struct httpstream);
        hs->bufptr = hs->buflen = NULL;

        /* Curl connection */
        hs->con = curl_easy_init();
        hs->url = g_strdup(ve->filename);
        curl_easy_setopt(hs->con, CURLOPT_URL, hs->url);
        curl_easy_setopt(hs->con, CURLOPT_CONNECTTIMEOUT, 5);
        curl_easy_setopt(hs->con, CURLOPT_USERAGENT, APP_NAME "/" APP_VERSION);

        curl_easy_setopt(hs->con, CURLOPT_WRITEFUNCTION, vfs_http_incoming);
        curl_easy_setopt(hs->con, CURLOPT_WRITEDATA, hs);

        hs->conm = curl_multi_init();
        curl_multi_add_handle(hs->conm, hs->con);

#ifdef __GLIBC__
        /* glibc systems should have fopencookie() */
        ret = fopencookie(hs, "rb", iofn);
#else /* !__GLIBC__ */
        /* BSD's */
        ret = funopen(hs, vfs_http_readfn, NULL, NULL, vfs_http_closefn);
#endif /* __GLIBC__ */
        if (ret == NULL)
                vfs_http_closefn(hs);

        return (ret);
}

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