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sortix--sortix/kernel/dtable.cpp
2014-03-01 14:37:39 +01:00

222 lines
5.7 KiB
C++

/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2011, 2012, 2013.
This file is part of Sortix.
Sortix is free software: you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or (at your option) any later
version.
Sortix 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
Sortix. If not, see <http://www.gnu.org/licenses/>.
dtable.cpp
Table of file descriptors.
*******************************************************************************/
#include <assert.h>
#include <errno.h>
#include <limits.h>
#include <string.h>
#include <sortix/fcntl.h>
#include <sortix/kernel/descriptor.h>
#include <sortix/kernel/dtable.h>
#include <sortix/kernel/kernel.h>
#include <sortix/kernel/kthread.h>
#include <sortix/kernel/process.h>
#include <sortix/kernel/refcount.h>
namespace Sortix {
DescriptorTable::DescriptorTable()
{
dtablelock = KTHREAD_MUTEX_INITIALIZER;
entries = NULL;
numentries = 0;
}
DescriptorTable::~DescriptorTable()
{
Reset();
}
bool DescriptorTable::IsGoodEntry(int i)
{
bool ret = 0 <= i && i < numentries && entries[i].desc;
return ret;
}
Ref<DescriptorTable> DescriptorTable::Fork()
{
ScopedLock lock(&dtablelock);
Ref<DescriptorTable> ret(new DescriptorTable);
if ( !ret ) { return Ref<DescriptorTable>(NULL); }
ret->entries = new dtableent_t[numentries];
if ( !ret->entries ) { return Ref<DescriptorTable>(NULL); }
for ( ret->numentries = 0; ret->numentries < numentries; ret->numentries++ )
{
int i = ret->numentries;
if ( entries[i].desc && !(entries[i].flags & FD_CLOFORK) )
ret->entries[i] = entries[i];
else
/* Already set to NULL in dtableent_t::desc constructor. */{}
}
return ret;
}
Ref<Descriptor> DescriptorTable::Get(int index)
{
ScopedLock lock(&dtablelock);
if ( !IsGoodEntry(index) ) { errno = EBADF; return Ref<Descriptor>(NULL); }
return entries[index].desc;
}
bool DescriptorTable::Enlargen(int atleast)
{
if ( numentries == INT_MAX ) { errno = EOVERFLOW; return -1; }
int newnumentries = INT_MAX - numentries < numentries ?
INT_MAX :
numentries ? 2 * numentries : 8;
if ( newnumentries < atleast )
newnumentries = atleast;
dtableent_t* newentries = new dtableent_t[newnumentries];
if ( !newentries )
return false;
for ( int i = 0; i < numentries; i++ )
newentries[i].desc = entries[i].desc,
newentries[i].flags = entries[i].flags;
for ( int i = numentries; i < newnumentries; i++ )
/* newentries[i].desc is set in dtableent_t::desc constructor */
newentries[i].flags = 0;
delete[] entries; entries = newentries;
numentries = newnumentries;
return true;
}
int DescriptorTable::AllocateInternal(Ref<Descriptor> desc, int flags,
int min_index)
{
// dtablelock is held.
if ( flags & ~__FD_ALLOWED_FLAGS )
return errno = EINVAL, -1;
if ( min_index < 0 )
return errno = EINVAL, -1;
for ( int i = min_index; i < numentries; i++ )
if ( !entries[i].desc )
{
entries[i].desc = desc;
entries[i].flags = flags;
return i;
}
int oldnumentries = numentries;
if ( !Enlargen(min_index) )
return -1;
int i = oldnumentries++;
entries[i].desc = desc;
entries[i].flags = flags;
return i;
}
int DescriptorTable::Allocate(Ref<Descriptor> desc, int flags, int min_index)
{
ScopedLock lock(&dtablelock);
return AllocateInternal(desc, flags, min_index);
}
int DescriptorTable::Allocate(int src_index, int flags, int min_index)
{
ScopedLock lock(&dtablelock);
if ( !IsGoodEntry(src_index) )
return errno = EBADF, -1;
return AllocateInternal(entries[src_index].desc, flags, min_index);
}
int DescriptorTable::Copy(int from, int to, int flags)
{
if ( flags & ~__FD_ALLOWED_FLAGS )
return errno = EINVAL, -1;
ScopedLock lock(&dtablelock);
if ( from < 0 || to < 0 )
return errno = EINVAL, -1;
if ( !(from < numentries) )
return errno = EBADF, -1;
if ( !entries[from].desc )
return errno = EBADF, -1;
if ( from == to )
return errno = EINVAL, -1;
while ( !(to < numentries) )
if ( !Enlargen(to+1) )
return -1;
if ( entries[to].desc != entries[from].desc )
{
if ( entries[to].desc )
/* TODO: Should this be synced or otherwise properly closed? */{}
entries[to].desc = entries[from].desc;
}
entries[to].flags = flags;
return to;
}
Ref<Descriptor> DescriptorTable::FreeKeep(int index)
{
ScopedLock lock(&dtablelock);
if ( !IsGoodEntry(index) ) { errno = EBADF; return Ref<Descriptor>(NULL); }
Ref<Descriptor> ret = entries[index].desc;
entries[index].desc.Reset();
return ret;
}
void DescriptorTable::Free(int index)
{
FreeKeep(index);
}
void DescriptorTable::OnExecute()
{
ScopedLock lock(&dtablelock);
for ( int i = 0; i < numentries; i++ )
{
if ( !entries[i].desc )
continue;
if ( !(entries[i].flags & FD_CLOEXEC) )
continue;
entries[i].desc.Reset();
}
}
void DescriptorTable::Reset()
{
ScopedLock lock(&dtablelock);
numentries = 0;
delete[] entries;
entries = NULL;
}
bool DescriptorTable::SetFlags(int index, int flags)
{
if ( flags & ~__FD_ALLOWED_FLAGS )
return errno = EINVAL, -1;
ScopedLock lock(&dtablelock);
if ( !IsGoodEntry(index) ) { errno = EBADF; return false; }
entries[index].flags = flags;
return true;
}
int DescriptorTable::GetFlags(int index)
{
ScopedLock lock(&dtablelock);
if ( !IsGoodEntry(index) ) { errno = EBADF; return -1; }
return entries[index].flags;
}
} // namespace Sortix