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/*
* read.c - FUSE read function
*
* This file is part of gnunet-fuse.
* Copyright (C) 2007 David Barksdale
*
* gnunet-fuse is free software; you can redistribute it and/or
* modify if under the terms of version 2 of the GNU General Public License
* as published by the Free Software Foundation.
*
* gnunet-fuse 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, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#define _XOPEN_SOURCE 500
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <fuse.h>
#include "gnfs.h"
struct read_data
{
char *buf;
guint size;
guint64 offset;
};
static void dpcb(unsigned long long totalBytes,
unsigned long long completedBytes, GNUNET_CronTime eta,
unsigned long long lastBlockOffset, const char *lastBlock,
unsigned int lastBlockSize, void *cls)
{
struct read_data *d = cls;
guint64 block_end = lastBlockOffset + lastBlockSize;
guint64 buf_end = d->offset + d->size;
(void)totalBytes;
(void)completedBytes;
(void)eta;
/* Check if this block is entirely before the buffer */
if(block_end < d->offset)
return;
/* Check if this block is entirely after the buffer */
if(lastBlockOffset > buf_end)
return;
/* Chop off residue at beginning of block */
if(lastBlockOffset < d->offset)
{
lastBlock += d->offset - lastBlockOffset;
lastBlockSize -= d->offset - lastBlockOffset;
lastBlockOffset = d->offset;
}
/* Chop off residue at end of block */
if(block_end > buf_end)
{
lastBlockSize -= block_end - buf_end;
}
memcpy(d->buf + (lastBlockOffset - d->offset), lastBlock,
lastBlockSize);
}
static int tt(void *cls)
{
(void)cls;
return fuse_interrupted() ? GNUNET_SYSERR : GNUNET_OK;
}
int gn_read(const char *path, char *buf, size_t size, off_t offset,
struct fuse_file_info *fi)
{
struct dirent *de;
struct read_data d;
char *special;
int ret;
ssize_t slen;
guint64 len;
(void)fi;
GNUNET_GE_LOG(ectx, GNUNET_GE_BULK | GNUNET_GE_DEVELOPER | GNUNET_GE_DEBUG,
"%s: called for '%s' %u bytes %lld offset\n", __FUNCTION__,
path, size, offset);
/* Check for special file */
special = gn_get_special_file(path);
if(special != NULL)
{
slen = strlen(special);
if(offset >= slen)
{
GNUNET_free(special);
return 0;
}
if( ((ssize_t) (offset + size)) > slen)
{
size = slen - offset;
}
memcpy(buf, special + offset, size);
GNUNET_free(special);
return size;
}
/* Lookup dirent for path */
de = gn_dirent_find(path);
if(de == NULL)
{
GNUNET_GE_LOG(ectx, GNUNET_GE_BULK | GNUNET_GE_DEVELOPER | GNUNET_GE_DEBUG,
"%s: file not found\n", __FUNCTION__);
return -ENOENT;
}
if(de->de_type != DE_FILE)
{
GNUNET_GE_LOG(ectx, GNUNET_GE_BULK | GNUNET_GE_DEVELOPER | GNUNET_GE_DEBUG,
"%s: not a file\n", __FUNCTION__);
size = -ENOENT;
goto out;
}
if(GNUNET_semaphore_down(de->de_sema, GNUNET_YES) == GNUNET_SYSERR)
{
size = -EIO;
goto out;
}
if(de->de_cached)
{
slen = pread(de->de_fd, buf, size, offset);
if(slen == -1)
size = -errno;
else
size = slen;
goto out_sema_up;
}
len = GNUNET_ECRS_uri_get_file_size(de->de_fi.uri);
if((guint64)offset >= len)
{
size = 0;
goto out_sema_up;
}
if((guint64)offset + size > len)
{
size = len - offset;
}
d.buf = buf;
d.size = size;
d.offset = offset;
ret = GNUNET_ECRS_file_download_partial(ectx, cfg, de->de_fi.uri, "/dev/null",
offset, size, anonymity, GNUNET_YES, dpcb, &d, tt, NULL);
if(ret != GNUNET_OK)
{
GNUNET_GE_LOG(ectx, GNUNET_GE_BULK | GNUNET_GE_USER | GNUNET_GE_ERROR,
"%s: failed to download file\n", __FUNCTION__);
size = -ENODATA;
}
out_sema_up:
GNUNET_semaphore_up(de->de_sema);
out:
gn_dirent_put(de);
return size;
}
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