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#include <Kernel/Process.h>
#include <Kernel/SharedBuffer.h>
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) {
dbgprintf("%s sanity -- SharedBuffer{%p} id: %d has total refs %d but we found %d\n", what, this, m_shared_buffer_id, m_total_refs, found_refs);
for (const auto& ref : m_refs) {
dbgprintf(" ref from pid %d: refcnt %d\n", ref.pid, 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()) {
ref.count++;
m_total_refs++;
if (ref.region == nullptr) {
ref.region = process.allocate_region_with_vmobject(VirtualAddress(), size(), m_vmobject, 0, "SharedBuffer", PROT_READ | (m_writable ? PROT_WRITE : 0));
ref.region->set_shared(true);
}
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());
for (auto& ref : m_refs) {
if (ref.pid == peer_pid) {
// don't increment the reference count yet; let them get_shared_buffer 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 (int 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
dbgprintf("Releasing shared buffer reference on %d of size %d by PID %d\n", m_shared_buffer_id, size(), process.pid());
#endif
process.deallocate_region(*ref.region);
m_refs.remove(i);
#ifdef SHARED_BUFFER_DEBUG
dbgprintf("Released shared buffer reference on %d of size %d by PID %d\n", m_shared_buffer_id, size(), 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 (int i = 0; i < m_refs.size(); ++i) {
auto& ref = m_refs[i];
if (ref.pid == pid) {
#ifdef SHARED_BUFFER_DEBUG
dbgprintf("Disowning shared buffer %d of size %d by PID %d\n", m_shared_buffer_id, size(), pid);
#endif
m_total_refs -= ref.count;
m_refs.remove(i);
#ifdef SHARED_BUFFER_DEBUG
dbgprintf("Disowned shared buffer %d of size %d by PID %d\n", m_shared_buffer_id, size(), 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
kprintf("Destroying unused SharedBuffer{%p} id: %d\n", this, m_shared_buffer_id);
#endif
auto count_before = shared_buffers().resource().size();
shared_buffers().resource().remove(m_shared_buffer_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();
}
}
}
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