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Kernel: Move file finding code to a helper

This commit is contained in:
Bananymous 2024-09-17 18:52:52 +03:00
parent a6b973003b
commit b779b3cf2d
2 changed files with 32 additions and 52 deletions
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2
kernel/include/kernel/Process.h
View File

@ -213,6 +213,8 @@ namespace Kernel
Process(const Credentials&, pid_t pid, pid_t parent, pid_t sid, pid_t pgrp); Process(const Credentials&, pid_t pid, pid_t parent, pid_t sid, pid_t pgrp);
static Process* create_process(const Credentials&, pid_t parent, pid_t sid = 0, pid_t pgrp = 0); static Process* create_process(const Credentials&, pid_t parent, pid_t sid = 0, pid_t pgrp = 0);
BAN::ErrorOr<VirtualFileSystem::File> find_file(int fd, const char* path, int flags);
BAN::ErrorOr<void> validate_string_access(const char*); BAN::ErrorOr<void> validate_string_access(const char*);
BAN::ErrorOr<void> validate_pointer_access_check(const void*, size_t, bool needs_write); BAN::ErrorOr<void> validate_pointer_access_check(const void*, size_t, bool needs_write);
BAN::ErrorOr<void> validate_pointer_access(const void*, size_t, bool needs_write); BAN::ErrorOr<void> validate_pointer_access(const void*, size_t, bool needs_write);

82
kernel/kernel/Process.cpp
View File

@ -351,6 +351,28 @@ namespace Kernel
return read_from_vec_of_str(m_environ, offset, buffer); return read_from_vec_of_str(m_environ, offset, buffer);
} }
BAN::ErrorOr<VirtualFileSystem::File> Process::find_file(int fd, const char* path, int flags)
{
ASSERT(m_process_lock.is_locked());
if (path)
TRY(validate_string_access(path));
VirtualFileSystem::File parent_file;
if (path && path[0] == '/')
parent_file = VirtualFileSystem::get().root_file();
else if (fd == AT_FDCWD)
parent_file = TRY(m_working_directory.clone());
else
parent_file = TRY(m_open_file_descriptors.file_of(fd));
auto file = path
? TRY(VirtualFileSystem::get().file_from_relative_path(parent_file, m_credentials, path, flags))
: BAN::move(parent_file);
return file;
}
BAN::ErrorOr<long> Process::sys_exit(int status) BAN::ErrorOr<long> Process::sys_exit(int status)
{ {
ASSERT(this == &Process::current()); ASSERT(this == &Process::current());
@ -1000,15 +1022,7 @@ namespace Kernel
TRY(validate_string_access(path)); TRY(validate_string_access(path));
TRY(validate_pointer_access(buffer, bufsize, true)); TRY(validate_pointer_access(buffer, bufsize, true));
VirtualFileSystem::File parent_file; auto inode = TRY(find_file(fd, path, O_NOFOLLOW | O_RDONLY)).inode;
if (path[0] == '/')
parent_file = VirtualFileSystem::get().root_file();
else if (fd == AT_FDCWD)
parent_file = TRY(m_working_directory.clone());
else
parent_file = TRY(m_open_file_descriptors.file_of(fd));
auto inode = TRY(VirtualFileSystem::get().file_from_relative_path(parent_file, m_credentials, path, O_NOFOLLOW | O_RDONLY)).inode;
// FIXME: no allocation needed // FIXME: no allocation needed
auto link_target = TRY(inode->link_target()); auto link_target = TRY(inode->link_target());
@ -1036,20 +1050,8 @@ namespace Kernel
flag = O_NOFOLLOW; flag = O_NOFOLLOW;
LockGuard _(m_process_lock); LockGuard _(m_process_lock);
if (path)
TRY(validate_string_access(path));
VirtualFileSystem::File parent_file; auto inode = TRY(find_file(fd, path, O_SEARCH | flag)).inode;
if (path && path[0] == '/')
parent_file = VirtualFileSystem::get().root_file();
else if (fd == AT_FDCWD)
parent_file = TRY(m_working_directory.clone());
else
parent_file = TRY(m_open_file_descriptors.file_of(fd));
auto inode = path
? TRY(VirtualFileSystem::get().file_from_relative_path(parent_file, m_credentials, path, flag)).inode
: parent_file.inode;
if (!m_credentials.is_superuser() && inode->uid() != m_credentials.euid()) if (!m_credentials.is_superuser() && inode->uid() != m_credentials.euid())
{ {
@ -1070,20 +1072,8 @@ namespace Kernel
flag = O_NOFOLLOW; flag = O_NOFOLLOW;
LockGuard _(m_process_lock); LockGuard _(m_process_lock);
if (path)
TRY(validate_string_access(path));
VirtualFileSystem::File parent_file; auto inode = TRY(find_file(fd, path, O_SEARCH | flag)).inode;
if (path && path[0] == '/')
parent_file = VirtualFileSystem::get().root_file();
else if (fd == AT_FDCWD)
parent_file = TRY(m_working_directory.clone());
else
parent_file = TRY(m_open_file_descriptors.file_of(fd));
auto inode = path
? TRY(VirtualFileSystem::get().file_from_relative_path(parent_file, m_credentials, path, flag)).inode
: parent_file.inode;
if (uid != -1 && !m_credentials.is_superuser()) if (uid != -1 && !m_credentials.is_superuser())
return BAN::Error::from_errno(EPERM); return BAN::Error::from_errno(EPERM);
@ -1425,29 +1415,17 @@ namespace Kernel
return {}; return {};
} }
BAN::ErrorOr<long> Process::sys_fstatat(int fd, const char* path, struct stat* buf, int flags) BAN::ErrorOr<long> Process::sys_fstatat(int fd, const char* path, struct stat* buf, int flag)
{ {
if (flags & ~AT_SYMLINK_NOFOLLOW) if (flag & ~AT_SYMLINK_NOFOLLOW)
return BAN::Error::from_errno(EINVAL); return BAN::Error::from_errno(EINVAL);
if (flags == AT_SYMLINK_NOFOLLOW) if (flag == AT_SYMLINK_NOFOLLOW)
flags = O_NOFOLLOW; flag = O_NOFOLLOW;
LockGuard _(m_process_lock); LockGuard _(m_process_lock);
if (path)
TRY(validate_string_access(path));
TRY(validate_pointer_access(buf, sizeof(struct stat), true)); TRY(validate_pointer_access(buf, sizeof(struct stat), true));
VirtualFileSystem::File parent_file; auto inode = TRY(find_file(fd, path, O_SEARCH | flag)).inode;
if (path && path[0] == '/')
parent_file = VirtualFileSystem::get().root_file();
else if (fd == AT_FDCWD)
parent_file = TRY(m_working_directory.clone());
else
parent_file = TRY(m_open_file_descriptors.file_of(fd));
const auto inode = path
? TRY(VirtualFileSystem::get().file_from_relative_path(parent_file, m_credentials, path, flags)).inode
: parent_file.inode;
buf->st_dev = inode->dev(); buf->st_dev = inode->dev();
buf->st_ino = inode->ino(); buf->st_ino = inode->ino();
buf->st_mode = inode->mode().mode; buf->st_mode = inode->mode().mode;