ladybird/Kernel/SharedBuffer.cpp
Liav A 0fc60e41dd Kernel: Use klog() instead of kprintf()
Also, duplicate data in dbg() and klog() calls were removed.
In addition, leakage of virtual address to kernel log is prevented.
This is done by replacing kprintf() calls to dbg() calls with the
leaked data instead.
Also, other kprintf() calls were replaced with klog().
2020-03-02 22:23:39 +01:00

196 lines
6.2 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* 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 COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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 <Kernel/Process.h>
#include <Kernel/SharedBuffer.h>
namespace Kernel {
Lockable<HashMap<int, NonnullOwnPtr<SharedBuffer>>>& shared_buffers()
{
static Lockable<HashMap<int, NonnullOwnPtr<SharedBuffer>>>* map;
if (!map)
map = new Lockable<HashMap<int, NonnullOwnPtr<SharedBuffer>>>;
return *map;
}
void SharedBuffer::sanity_check(const char* what)
{
LOCKER(shared_buffers().lock());
unsigned found_refs = 0;
for (const auto& ref : m_refs)
found_refs += ref.count;
if (found_refs != m_total_refs) {
dbg() << what << " sanity -- SharedBuffer{" << this << "} id: " << m_shbuf_id << " has total refs " << m_total_refs << " but we found " << found_refs;
for (const auto& ref : m_refs) {
dbg() << " ref from pid " << ref.pid << ": refcnt " << ref.count;
}
ASSERT_NOT_REACHED();
}
}
bool SharedBuffer::is_shared_with(pid_t peer_pid)
{
LOCKER(shared_buffers().lock());
if (m_global)
return true;
for (auto& ref : m_refs) {
if (ref.pid == peer_pid) {
return true;
}
}
return false;
}
void* SharedBuffer::ref_for_process_and_get_address(Process& process)
{
LOCKER(shared_buffers().lock());
ASSERT(is_shared_with(process.pid()));
if (m_global) {
bool found = false;
for (auto& ref : m_refs) {
if (ref.pid == process.pid()) {
found = true;
break;
}
}
if (!found)
m_refs.append(Reference(process.pid()));
}
for (auto& ref : m_refs) {
if (ref.pid == process.pid()) {
if (!ref.region) {
auto* region = process.allocate_region_with_vmobject(VirtualAddress(), size(), m_vmobject, 0, "SharedBuffer", PROT_READ | (m_writable ? PROT_WRITE : 0));
if (!region)
return (void*)-ENOMEM;
ref.region = region->make_weak_ptr();
ref.region->set_shared(true);
}
ref.count++;
m_total_refs++;
sanity_check("ref_for_process_and_get_address");
return ref.region->vaddr().as_ptr();
}
}
ASSERT_NOT_REACHED();
}
void SharedBuffer::share_with(pid_t peer_pid)
{
LOCKER(shared_buffers().lock());
if (m_global)
return;
for (auto& ref : m_refs) {
if (ref.pid == peer_pid) {
// don't increment the reference count yet; let them shbuf_get it first.
sanity_check("share_with (old ref)");
return;
}
}
m_refs.append(Reference(peer_pid));
sanity_check("share_with (new ref)");
}
void SharedBuffer::deref_for_process(Process& process)
{
LOCKER(shared_buffers().lock());
for (size_t i = 0; i < m_refs.size(); ++i) {
auto& ref = m_refs[i];
if (ref.pid == process.pid()) {
ref.count--;
m_total_refs--;
if (ref.count == 0) {
#ifdef SHARED_BUFFER_DEBUG
dbg() << "Releasing shared buffer reference on " << m_shbuf_id << " of size " << size() << " by PID " << process.pid();
#endif
process.deallocate_region(*ref.region);
m_refs.unstable_remove(i);
#ifdef SHARED_BUFFER_DEBUG
dbg() << "Released shared buffer reference on " << m_shbuf_id << " of size " << size() << " by PID " << process.pid();
#endif
sanity_check("deref_for_process");
destroy_if_unused();
return;
}
return;
}
}
ASSERT_NOT_REACHED();
}
void SharedBuffer::disown(pid_t pid)
{
LOCKER(shared_buffers().lock());
for (size_t i = 0; i < m_refs.size(); ++i) {
auto& ref = m_refs[i];
if (ref.pid == pid) {
#ifdef SHARED_BUFFER_DEBUG
dbg() << "Disowning shared buffer " << m_shbuf_id << " of size " << size() << " by PID " << pid;
#endif
m_total_refs -= ref.count;
m_refs.unstable_remove(i);
#ifdef SHARED_BUFFER_DEBUG
dbg() << "Disowned shared buffer " << m_shbuf_id << " of size " << size() << " by PID " << pid;
#endif
destroy_if_unused();
return;
}
}
}
void SharedBuffer::destroy_if_unused()
{
LOCKER(shared_buffers().lock());
sanity_check("destroy_if_unused");
if (m_total_refs == 0) {
#ifdef SHARED_BUFFER_DEBUG
dbg() << "Destroying unused SharedBuffer{" << this << "} id: " << m_shbuf_id;
#endif
auto count_before = shared_buffers().resource().size();
shared_buffers().resource().remove(m_shbuf_id);
ASSERT(count_before != shared_buffers().resource().size());
}
}
void SharedBuffer::seal()
{
LOCKER(shared_buffers().lock());
m_writable = false;
for (auto& ref : m_refs) {
if (ref.region) {
ref.region->set_writable(false);
ref.region->remap();
}
}
}
}