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Kernel: Separate VFS stat() from open().

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It was very confusing that you had to open a FileDescriptor in order to stat
a file. This patch gives VFS a separate stat() function and uses it to
implement the stat() and lstat() syscalls.
This commit is contained in:
Andreas Kling 2019-02-21 16:09:12 +01:00
parent f5f136931a
commit ce3b548077
3 changed files with 20 additions and 8 deletions
Download patch file Download diff file Expand all files Collapse all files

10
Kernel/Process.cpp
View file

@ -1217,10 +1217,9 @@ int Process::sys$lstat(const char* path, stat* statbuf)
if (!validate_write_typed(statbuf)) if (!validate_write_typed(statbuf))
return -EFAULT; return -EFAULT;
int error; int error;
auto descriptor = VFS::the().open(move(path), error, O_NOFOLLOW_NOERROR | O_DONT_OPEN_DEVICE, 0, *cwd_inode()); if (!VFS::the().stat(move(path), error, O_NOFOLLOW_NOERROR, *cwd_inode(), *statbuf))
if (!descriptor)
return error; return error;
return descriptor->fstat(statbuf); return 0;
} }
int Process::sys$stat(const char* path, stat* statbuf) int Process::sys$stat(const char* path, stat* statbuf)
@ -1228,10 +1227,9 @@ int Process::sys$stat(const char* path, stat* statbuf)
if (!validate_write_typed(statbuf)) if (!validate_write_typed(statbuf))
return -EFAULT; return -EFAULT;
int error; int error;
auto descriptor = VFS::the().open(move(path), error, O_DONT_OPEN_DEVICE, 0, *cwd_inode()); if (!VFS::the().stat(move(path), error, 0, *cwd_inode(), *statbuf))
if (!descriptor)
return error; return error;
return descriptor->fstat(statbuf); return 0;
} }
int Process::sys$readlink(const char* path, char* buffer, size_t size) int Process::sys$readlink(const char* path, char* buffer, size_t size)

16
Kernel/VirtualFileSystem.cpp
View file

@ -131,6 +131,17 @@ RetainPtr<FileDescriptor> VFS::open(RetainPtr<Device>&& device, int& error, int
return FileDescriptor::create(move(device)); return FileDescriptor::create(move(device));
} }
bool VFS::stat(const String& path, int& error, int options, Inode& base, struct stat& statbuf)
{
auto inode_id = resolve_path(path, base.identifier(), error, options);
if (!inode_id.is_valid())
return false;
error = FileDescriptor::create(get_inode(inode_id))->fstat(&statbuf);
if (error)
return false;
return true;
}
RetainPtr<FileDescriptor> VFS::open(const String& path, int& error, int options, mode_t mode, Inode& base) RetainPtr<FileDescriptor> VFS::open(const String& path, int& error, int options, mode_t mode, Inode& base)
{ {
auto inode_id = resolve_path(path, base.identifier(), error, options); auto inode_id = resolve_path(path, base.identifier(), error, options);
@ -145,7 +156,9 @@ RetainPtr<FileDescriptor> VFS::open(const String& path, int& error, int options,
} }
if (!inode) if (!inode)
return nullptr; return nullptr;
auto metadata = inode->metadata(); auto metadata = inode->metadata();
// NOTE: Read permission is a bit weird, since O_RDONLY == 0, // NOTE: Read permission is a bit weird, since O_RDONLY == 0,
// so we check if (NOT write_only OR read_and_write) // so we check if (NOT write_only OR read_and_write)
if (!(options & O_WRONLY) || (options & O_RDWR)) { if (!(options & O_WRONLY) || (options & O_RDWR)) {
@ -160,7 +173,8 @@ RetainPtr<FileDescriptor> VFS::open(const String& path, int& error, int options,
return nullptr; return nullptr;
} }
} }
if (!(options & O_DONT_OPEN_DEVICE) && metadata.is_device()) {
if (metadata.is_device()) {
auto it = m_devices.find(encoded_device(metadata.major_device, metadata.minor_device)); auto it = m_devices.find(encoded_device(metadata.major_device, metadata.minor_device));
if (it == m_devices.end()) { if (it == m_devices.end()) {
kprintf("VFS::open: no such device %u,%u\n", metadata.major_device, metadata.minor_device); kprintf("VFS::open: no such device %u,%u\n", metadata.major_device, metadata.minor_device);

2
Kernel/VirtualFileSystem.h
View file

@ -24,7 +24,6 @@
#define O_NOFOLLOW 00400000 #define O_NOFOLLOW 00400000
#define O_CLOEXEC 02000000 #define O_CLOEXEC 02000000
#define O_NOFOLLOW_NOERROR 0x4000000 #define O_NOFOLLOW_NOERROR 0x4000000
#define O_DONT_OPEN_DEVICE 0x8000000
class Device; class Device;
class FileDescriptor; class FileDescriptor;
@ -70,6 +69,7 @@ public:
bool unlink(const String& path, Inode& base, int& error); bool unlink(const String& path, Inode& base, int& error);
bool rmdir(const String& path, Inode& base, int& error); bool rmdir(const String& path, Inode& base, int& error);
bool chmod(const String& path, mode_t, Inode& base, int& error); bool chmod(const String& path, mode_t, Inode& base, int& error);
bool stat(const String& path, int& error, int options, Inode& base, struct stat&);
void register_device(Device&); void register_device(Device&);
void unregister_device(Device&); void unregister_device(Device&);