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Add a C++ helper class for working with shared buffers.

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This is a bit more comfortable than passing the shared buffer ID manually
everywhere and keeping track of size etc.
This commit is contained in:
Andreas Kling 2019-03-08 12:22:55 +01:00
parent 0b5d5fc3c9
commit eda0866992
14 changed files with 186 additions and 46 deletions
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65
Kernel/Process.cpp
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@ -2513,7 +2513,7 @@ KResult Process::wait_for_connect(Socket& socket)
}
struct SharedBuffer {
SharedBuffer(pid_t pid1, pid_t pid2, size_t size)
SharedBuffer(pid_t pid1, pid_t pid2, int size)
: m_pid1(pid1)
, m_pid2(pid2)
, m_vmo(VMObject::create_anonymous(size))
@ -2526,14 +2526,14 @@ struct SharedBuffer {
if (m_pid1 == process.pid()) {
++m_pid1_retain_count;
if (!m_pid1_region) {
m_pid1_region = process.allocate_region_with_vmo(LinearAddress(), size(), m_vmo.copy_ref(), 0, "SharedBuffer", true, true);
m_pid1_region = process.allocate_region_with_vmo(LinearAddress(), size(), m_vmo.copy_ref(), 0, "SharedBuffer", true, m_pid1_writable);
m_pid1_region->set_shared(true);
}
return m_pid1_region->laddr().as_ptr();
} else if (m_pid2 == process.pid()) {
++m_pid2_retain_count;
if (!m_pid2_region) {
m_pid2_region = process.allocate_region_with_vmo(LinearAddress(), size(), m_vmo.copy_ref(), 0, "SharedBuffer", true, true);
m_pid2_region = process.allocate_region_with_vmo(LinearAddress(), size(), m_vmo.copy_ref(), 0, "SharedBuffer", true, m_pid2_writable);
m_pid2_region->set_shared(true);
}
return m_pid2_region->laddr().as_ptr();
@ -2584,6 +2584,20 @@ struct SharedBuffer {
size_t size() const { return m_vmo->size(); }
void destroy_if_unused();
void seal()
{
m_pid1_writable = false;
m_pid2_writable = false;
if (m_pid1_region) {
m_pid1_region->set_writable(false);
MM.remap_region(*m_pid1_region->page_directory(), *m_pid1_region);
}
if (m_pid2_region) {
m_pid2_region->set_writable(false);
MM.remap_region(*m_pid2_region->page_directory(), *m_pid2_region);
}
}
int m_shared_buffer_id { -1 };
pid_t m_pid1;
pid_t m_pid2;
@ -2591,6 +2605,8 @@ struct SharedBuffer {
unsigned m_pid2_retain_count { 0 };
Region* m_pid1_region { nullptr };
Region* m_pid2_region { nullptr };
bool m_pid1_writable { false };
bool m_pid2_writable { false };
Retained<VMObject> m_vmo;
};
@ -2608,7 +2624,7 @@ void SharedBuffer::destroy_if_unused()
if (!m_pid1_retain_count && !m_pid2_retain_count) {
LOCKER(shared_buffers().lock());
#ifdef SHARED_BUFFER_DEBUG
dbgprintf("Destroying unused SharedBuffer{%p} id: %d (pid1: %d, pid2: %d)\n", this, m_shared_buffer_id, m_pid1, m_pid2);
kprintf("Destroying unused SharedBuffer{%p} id: %d (pid1: %d, pid2: %d)\n", this, m_shared_buffer_id, m_pid1, m_pid2);
#endif
size_t count_before = shared_buffers().resource().size();
shared_buffers().resource().remove(m_shared_buffer_id);
@ -2626,9 +2642,9 @@ void Process::disown_all_shared_buffers()
shared_buffer->disown(m_pid);
}
int Process::sys$create_shared_buffer(pid_t peer_pid, size_t size, void** buffer)
int Process::sys$create_shared_buffer(pid_t peer_pid, int size, void** buffer)
{
if (!size)
if (!size || size < 0)
return -EINVAL;
size = PAGE_ROUND_UP(size);
if (!peer_pid || peer_pid < 0 || peer_pid == m_pid)
@ -2650,7 +2666,7 @@ int Process::sys$create_shared_buffer(pid_t peer_pid, size_t size, void** buffer
shared_buffer->m_pid1_region->set_shared(true);
*buffer = shared_buffer->m_pid1_region->laddr().as_ptr();
#ifdef SHARED_BUFFER_DEBUG
dbgprintf("%s(%u): Created shared buffer %d (%u bytes, vmo is %u) for sharing with %d\n", name().characters(), pid(),shared_buffer_id, size, shared_buffer->size(), peer_pid);
kprintf("%s(%u): Created shared buffer %d (%u bytes, vmo is %u) for sharing with %d\n", name().characters(), pid(),shared_buffer_id, size, shared_buffer->size(), peer_pid);
#endif
shared_buffers().resource().set(shared_buffer_id, move(shared_buffer));
return shared_buffer_id;
@ -2664,7 +2680,7 @@ int Process::sys$release_shared_buffer(int shared_buffer_id)
return -EINVAL;
auto& shared_buffer = *(*it).value;
#ifdef SHARED_BUFFER_DEBUG
dbgprintf("%s(%u): Releasing shared buffer %d, buffer count: %u\n", name().characters(), pid(), shared_buffer_id, shared_buffers().resource().size());
kprintf("%s(%u): Releasing shared buffer %d, buffer count: %u\n", name().characters(), pid(), shared_buffer_id, shared_buffers().resource().size());
#endif
shared_buffer.release(*this);
return 0;
@ -2680,11 +2696,42 @@ void* Process::sys$get_shared_buffer(int shared_buffer_id)
if (shared_buffer.pid1() != m_pid && shared_buffer.pid2() != m_pid)
return (void*)-EINVAL;
#ifdef SHARED_BUFFER_DEBUG
dbgprintf("%s(%u): Retaining shared buffer %d, buffer count: %u\n", name().characters(), pid(), shared_buffer_id, shared_buffers().resource().size());
kprintf("%s(%u): Retaining shared buffer %d, buffer count: %u\n", name().characters(), pid(), shared_buffer_id, shared_buffers().resource().size());
#endif
return shared_buffer.retain(*this);
}
int Process::sys$seal_shared_buffer(int shared_buffer_id)
{
LOCKER(shared_buffers().lock());
auto it = shared_buffers().resource().find(shared_buffer_id);
if (it == shared_buffers().resource().end())
return -EINVAL;
auto& shared_buffer = *(*it).value;
if (shared_buffer.pid1() != m_pid && shared_buffer.pid2() != m_pid)
return -EINVAL;
#ifdef SHARED_BUFFER_DEBUG
kprintf("%s(%u): Sealing shared buffer %d\n", name().characters(), pid(), shared_buffer_id);
#endif
shared_buffer.seal();
return 0;
}
int Process::sys$get_shared_buffer_size(int shared_buffer_id)
{
LOCKER(shared_buffers().lock());
auto it = shared_buffers().resource().find(shared_buffer_id);
if (it == shared_buffers().resource().end())
return -EINVAL;
auto& shared_buffer = *(*it).value;
if (shared_buffer.pid1() != m_pid && shared_buffer.pid2() != m_pid)
return -EINVAL;
#ifdef SHARED_BUFFER_DEBUG
kprintf("%s(%u): Get shared buffer %d size: %u\n", name().characters(), pid(), shared_buffer_id, shared_buffers().resource().size());
#endif
return shared_buffer.size();
}
const char* to_string(Process::State state)
{
switch (state) {