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/*
Copyright (c) 2016, Antonio SJ Musumeci <trapexit@spawn.link>
Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <fuse.h>
#include <sys/statvfs.h>
#include <errno.h>
#include <algorithm>
#include <climits>
#include <map>
#include <string>
#include <vector>
#include "config.hpp"
#include "rwlock.hpp"
#include "success_fail.hpp"
#include "ugid.hpp"
using std::string;
using std::map;
using std::vector;
static
void
_normalize_statvfs(struct statvfs *fsstat,
const unsigned long min_bsize,
const unsigned long min_frsize,
const unsigned long min_namemax)
{
fsstat->f_blocks = (fsblkcnt_t)((fsstat->f_blocks * fsstat->f_frsize) / min_frsize);
fsstat->f_bfree = (fsblkcnt_t)((fsstat->f_bfree * fsstat->f_frsize) / min_frsize);
fsstat->f_bavail = (fsblkcnt_t)((fsstat->f_bavail * fsstat->f_frsize) / min_frsize);
fsstat->f_bsize = min_bsize;
fsstat->f_frsize = min_frsize;
fsstat->f_namemax = min_namemax;
}
static
void
_merge_statvfs(struct statvfs * const out,
const struct statvfs * const in)
{
out->f_blocks += in->f_blocks;
out->f_bfree += in->f_bfree;
out->f_bavail += in->f_bavail;
out->f_files += in->f_files;
out->f_ffree += in->f_ffree;
out->f_favail += in->f_favail;
}
static
void
_statfs_core(const char *srcmount,
unsigned long &min_bsize,
unsigned long &min_frsize,
unsigned long &min_namemax,
map<dev_t,struct statvfs> &fsstats)
{
int rv;
struct stat st;
struct statvfs fsstat;
rv = ::statvfs(srcmount,&fsstat);
if(STATVFS_FAILED(rv))
return;
rv = ::stat(srcmount,&st);
if(STAT_FAILED(rv))
return;
if(min_bsize > fsstat.f_bsize)
min_bsize = fsstat.f_bsize;
if(min_frsize > fsstat.f_frsize)
min_frsize = fsstat.f_frsize;
if(min_namemax > fsstat.f_namemax)
min_namemax = fsstat.f_namemax;
fsstats.insert(std::make_pair(st.st_dev,fsstat));
}
static
int
_statfs(const vector<string> &srcmounts,
struct statvfs &fsstat)
{
map<dev_t,struct statvfs> fsstats;
unsigned long min_bsize = ULONG_MAX;
unsigned long min_frsize = ULONG_MAX;
unsigned long min_namemax = ULONG_MAX;
for(size_t i = 0, ei = srcmounts.size(); i < ei; i++)
{
_statfs_core(srcmounts[i].c_str(),min_bsize,min_frsize,min_namemax,fsstats);
}
map<dev_t,struct statvfs>::iterator iter = fsstats.begin();
map<dev_t,struct statvfs>::iterator enditer = fsstats.end();
if(iter != enditer)
{
fsstat = iter->second;
_normalize_statvfs(&fsstat,min_bsize,min_frsize,min_namemax);
for(++iter; iter != enditer; ++iter)
{
_normalize_statvfs(&iter->second,min_bsize,min_frsize,min_namemax);
_merge_statvfs(&fsstat,&iter->second);
}
}
return 0;
}
namespace mergerfs
{
namespace fuse
{
int
statfs(const char *fusepath,
struct statvfs *stat)
{
const fuse_context *fc = fuse_get_context();
const Config &config = Config::get(fc);
const ugid::Set ugid(fc->uid,fc->gid);
const rwlock::ReadGuard readlock(&config.srcmountslock);
return _statfs(config.srcmounts,
*stat);
}
}
}