123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161 |
- #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();
- }
- }
- }
|