RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-31 21:08:12 +00:00
Code Issues Activity Actions

Kernel: Implement basic support for sys$mmap() with MAP_PRIVATE

Browse source 
You can now mmap a file as private and writable, and the changes you
make will only be visible to you.

This works because internally a MAP_PRIVATE region is backed by a
unique PrivateInodeVMObject instead of using the globally shared
SharedInodeVMObject like we always did before. :^)

Fixes #1045.
This commit is contained in:
Andreas Kling 2020-02-28 20:47:27 +01:00
parent aa1e209845
commit 8fbdda5a2d
11 changed files with 45 additions and 31 deletions
Download patch file Download diff file Expand all files Collapse all files

2
Kernel/FileSystem/File.cpp
View file

@ -54,7 +54,7 @@ int File::ioctl(FileDescription&, unsigned, unsigned)
return -ENOTTY;
}
KResultOr<Region*> File::mmap(Process&, FileDescription&, VirtualAddress, size_t, size_t, int)
KResultOr<Region*> File::mmap(Process&, FileDescription&, VirtualAddress, size_t, size_t, int, bool)
{
return KResult(-ENODEV);
}

2
Kernel/FileSystem/File.h
View file

@ -77,7 +77,7 @@ public:
virtual ssize_t read(FileDescription&, u8*, ssize_t) = 0;
virtual ssize_t write(FileDescription&, const u8*, ssize_t) = 0;
virtual int ioctl(FileDescription&, unsigned request, unsigned arg);
virtual KResultOr<Region*> mmap(Process&, FileDescription&, VirtualAddress preferred_vaddr, size_t offset, size_t size, int prot);
virtual KResultOr<Region*> mmap(Process&, FileDescription&, VirtualAddress preferred_vaddr, size_t offset, size_t size, int prot, bool shared);
virtual String absolute_path(const FileDescription&) const = 0;

4
Kernel/FileSystem/FileDescription.cpp
View file

@ -281,10 +281,10 @@ InodeMetadata FileDescription::metadata() const
return {};
}
KResultOr<Region*> FileDescription::mmap(Process& process, VirtualAddress vaddr, size_t offset, size_t size, int prot)
KResultOr<Region*> FileDescription::mmap(Process& process, VirtualAddress vaddr, size_t offset, size_t size, int prot, bool shared)
{
LOCKER(m_lock);
return m_file->mmap(process, *this, vaddr, offset, size, prot);
return m_file->mmap(process, *this, vaddr, offset, size, prot, shared);
}
KResult FileDescription::truncate(u64 length)

2
Kernel/FileSystem/FileDescription.h
View file

@ -109,7 +109,7 @@ public:
Custody* custody() { return m_custody.ptr(); }
const Custody* custody() const { return m_custody.ptr(); }
KResultOr<Region*> mmap(Process&, VirtualAddress, size_t offset, size_t, int prot);
KResultOr<Region*> mmap(Process&, VirtualAddress, size_t offset, size_t, int prot, bool shared);
bool is_blocking() const { return m_is_blocking; }
void set_blocking(bool b) { m_is_blocking = b; }

12
Kernel/FileSystem/InodeFile.cpp
View file

@ -29,6 +29,7 @@
#include <Kernel/FileSystem/InodeFile.h>
#include <Kernel/FileSystem/VirtualFileSystem.h>
#include <Kernel/Process.h>
#include <Kernel/VM/PrivateInodeVMObject.h>
#include <Kernel/VM/SharedInodeVMObject.h>
namespace Kernel {
@ -60,11 +61,18 @@ ssize_t InodeFile::write(FileDescription& description, const u8* data, ssize_t c
return nwritten;
}
KResultOr<Region*> InodeFile::mmap(Process& process, FileDescription& description, VirtualAddress preferred_vaddr, size_t offset, size_t size, int prot)
KResultOr<Region*> InodeFile::mmap(Process& process, FileDescription& description, VirtualAddress preferred_vaddr, size_t offset, size_t size, int prot, bool shared)
{
ASSERT(offset == 0);
// FIXME: If PROT_EXEC, check that the underlying file system isn't mounted noexec.
auto* region = process.allocate_region_with_vmobject(preferred_vaddr, size, SharedInodeVMObject::create_with_inode(inode()), offset, description.absolute_path(), prot);
RefPtr<InodeVMObject> vmobject;
if (shared)
vmobject = SharedInodeVMObject::create_with_inode(inode());
else
vmobject = PrivateInodeVMObject::create_with_inode(inode());
if (!vmobject)
return KResult(-ENOMEM);
auto* region = process.allocate_region_with_vmobject(preferred_vaddr, size, *vmobject, offset, description.absolute_path(), prot);
if (!region)
return KResult(-ENOMEM);
return region;

2
Kernel/FileSystem/InodeFile.h
View file

@ -49,7 +49,7 @@ public:
virtual ssize_t read(FileDescription&, u8*, ssize_t) override;
virtual ssize_t write(FileDescription&, const u8*, ssize_t) override;
virtual KResultOr<Region*> mmap(Process&, FileDescription&, VirtualAddress preferred_vaddr, size_t offset, size_t size, int prot) override;
virtual KResultOr<Region*> mmap(Process&, FileDescription&, VirtualAddress preferred_vaddr, size_t offset, size_t size, int prot, bool shared) override;
virtual String absolute_path(const FileDescription&) const override;