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banan-os/kernel/kernel/Process.cpp

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#include <BAN/StringView.h>
#include <kernel/CriticalScope.h>
#include <kernel/FS/VirtualFileSystem.h>
#include <kernel/LockGuard.h>
#include <kernel/Memory/Heap.h>
#include <kernel/Memory/PageTableScope.h>
#include <kernel/Process.h>
#include <kernel/Scheduler.h>
#include <LibELF/ELF.h>
#include <LibELF/Values.h>
#include <fcntl.h>
#include <stdio.h>
namespace Kernel
{
static BAN::Vector<Process*> s_processes;
static SpinLock s_process_lock;
Process* Process::create_process(const Credentials& credentials)
{
static pid_t s_next_pid = 1;
auto* process = new Process(credentials, s_next_pid++);
ASSERT(process);
return process;
}
void Process::register_process(Process* process)
{
s_process_lock.lock();
MUST(s_processes.push_back(process));
s_process_lock.unlock();
for (auto* thread : process->m_threads)
MUST(Scheduler::get().add_thread(thread));
}
Process* Process::create_kernel(entry_t entry, void* data)
{
auto* process = create_process({ 0, 0, 0, 0 });
MUST(process->m_working_directory.push_back('/'));
auto* thread = MUST(Thread::create_kernel(entry, data, process));
process->add_thread(thread);
register_process(process);
return process;
}
BAN::ErrorOr<Process*> Process::create_userspace(const Credentials& credentials, BAN::StringView path)
{
auto elf = TRY(load_elf_for_exec(credentials, path, "/"sv, {}));
auto* process = create_process(credentials);
MUST(process->m_working_directory.push_back('/'));
process->m_page_table = BAN::UniqPtr<PageTable>::adopt(MUST(PageTable::create_userspace()));;
process->load_elf_to_memory(*elf);
process->m_userspace_info.entry = elf->file_header_native().e_entry;
// NOTE: we clear the elf since we don't need the memory anymore
elf.clear();
char** argv = nullptr;
char** envp = nullptr;
{
PageTableScope _(process->page_table());
argv = (char**)MUST(process->sys_alloc(sizeof(char**) * 2));
argv[0] = (char*)MUST(process->sys_alloc(path.size() + 1));
memcpy(argv[0], path.data(), path.size());
argv[0][path.size()] = '\0';
argv[1] = nullptr;
BAN::StringView env1 = "PATH=/bin:/usr/bin"sv;
envp = (char**)MUST(process->sys_alloc(sizeof(char**) * 2));
envp[0] = (char*)MUST(process->sys_alloc(env1.size() + 1));
memcpy(envp[0], env1.data(), env1.size());
envp[0][env1.size()] = '\0';
envp[1] = nullptr;
}
process->m_userspace_info.argc = 1;
process->m_userspace_info.argv = argv;
process->m_userspace_info.envp = envp;
auto* thread = MUST(Thread::create_userspace(process));
process->add_thread(thread);
register_process(process);
return process;
}
Process::Process(const Credentials& credentials, pid_t pid)
: m_credentials(credentials)
, m_pid(pid)
, m_tty(TTY::current())
{ }
Process::~Process()
{
ASSERT(m_threads.empty());
ASSERT(m_fixed_width_allocators.empty());
ASSERT(!m_general_allocator);
ASSERT(m_mapped_ranges.empty());
ASSERT(&PageTable::current() != m_page_table.ptr());
dprintln("process {} exit", pid());
}
void Process::add_thread(Thread* thread)
{
LockGuard _(m_lock);
MUST(m_threads.push_back(thread));
}
void Process::on_thread_exit(Thread& thread)
{
LockGuard _(m_lock);
for (size_t i = 0; i < m_threads.size(); i++)
if (m_threads[i] == &thread)
m_threads.remove(i);
if (m_threads.empty())
exit(0);
}
void Process::exit(int status)
{
m_lock.lock();
m_exit_status.exit_code = status;
m_exit_status.exited = true;
while (m_exit_status.waiting > 0)
{
m_exit_status.semaphore.unblock();
m_lock.unlock();
Scheduler::get().reschedule();
m_lock.lock();
}
m_threads.clear();
for (auto& open_fd : m_open_files)
open_fd.inode = nullptr;
// NOTE: We must unmap ranges while the page table is still alive
for (auto* range : m_mapped_ranges)
delete range;
m_mapped_ranges.clear();
// NOTE: We must clear allocators while the page table is still alive
m_fixed_width_allocators.clear();
m_general_allocator.clear();
s_process_lock.lock();
for (size_t i = 0; i < s_processes.size(); i++)
if (s_processes[i] == this)
s_processes.remove(i);
s_process_lock.unlock();
// FIXME: we can't assume this is the current process
ASSERT(&Process::current() == this);
Scheduler::get().set_current_process_done();
}
BAN::ErrorOr<long> Process::sys_exit(int status)
{
exit(status);
ASSERT_NOT_REACHED();
}
BAN::ErrorOr<long> Process::sys_gettermios(::termios* termios)
{
LockGuard _(m_lock);
if (m_tty == nullptr)
return BAN::Error::from_errno(ENOTTY);
Kernel::termios ktermios = m_tty->get_termios();
termios->c_lflag = 0;
if (ktermios.canonical)
termios->c_lflag |= ICANON;
if (ktermios.echo)
termios->c_lflag |= ECHO;
return 0;
}
BAN::ErrorOr<long> Process::sys_settermios(const ::termios* termios)
{
LockGuard _(m_lock);
if (m_tty == nullptr)
return BAN::Error::from_errno(ENOTTY);
Kernel::termios ktermios;
ktermios.echo = termios->c_lflag & ECHO;
ktermios.canonical = termios->c_lflag & ICANON;
m_tty->set_termios(ktermios);
return 0;
}
BAN::ErrorOr<BAN::UniqPtr<LibELF::ELF>> Process::load_elf_for_exec(const Credentials& credentials, BAN::StringView file_path, const BAN::String& cwd, const BAN::Vector<BAN::StringView>& path_env)
{
if (file_path.empty())
return BAN::Error::from_errno(ENOENT);
BAN::String absolute_path;
if (file_path.front() == '/')
{
// We have an absolute path
TRY(absolute_path.append(file_path));
}
else if (file_path.front() == '.' || file_path.contains('/'))
{
// We have a relative path
TRY(absolute_path.append(cwd));
TRY(absolute_path.push_back('/'));
TRY(absolute_path.append(file_path));
}
else
{
// We have neither relative or absolute path,
// search from PATH environment
for (auto path_part : path_env)
{
if (path_part.empty())
continue;
if (path_part.front() != '/')
{
TRY(absolute_path.append(cwd));
TRY(absolute_path.push_back('/'));
}
TRY(absolute_path.append(path_part));
TRY(absolute_path.push_back('/'));
TRY(absolute_path.append(file_path));
if (!VirtualFileSystem::get().file_from_absolute_path(credentials, absolute_path, O_EXEC).is_error())
break;
absolute_path.clear();
}
if (absolute_path.empty())
return BAN::Error::from_errno(ENOENT);
}
auto file = TRY(VirtualFileSystem::get().file_from_absolute_path(credentials, absolute_path, O_EXEC));
auto elf_or_error = LibELF::ELF::load_from_file(file.inode);
if (elf_or_error.is_error())
{
if (elf_or_error.error().get_error_code() == EINVAL)
return BAN::Error::from_errno(ENOEXEC);
return elf_or_error.error();
}
auto elf = elf_or_error.release_value();
if (!elf->is_native())
{
derrorln("ELF has invalid architecture");
return BAN::Error::from_errno(EINVAL);
}
if (elf->file_header_native().e_type != LibELF::ET_EXEC)
{
derrorln("Not an executable");
return BAN::Error::from_errno(ENOEXEC);
}
return BAN::move(elf);
}
BAN::ErrorOr<long> Process::sys_fork(uintptr_t rsp, uintptr_t rip)
{
Process* forked = create_process(m_credentials);
forked->m_page_table = BAN::UniqPtr<PageTable>::adopt(MUST(PageTable::create_userspace()));
LockGuard _(m_lock);
forked->m_tty = m_tty;
forked->m_working_directory = m_working_directory;
forked->m_open_files = m_open_files;
forked->m_userspace_info = m_userspace_info;
for (auto* mapped_range : m_mapped_ranges)
MUST(forked->m_mapped_ranges.push_back(mapped_range->clone(forked->page_table())));
for (auto& allocator : m_fixed_width_allocators)
if (allocator->allocations() > 0)
MUST(forked->m_fixed_width_allocators.push_back(MUST(allocator->clone(forked->page_table()))));
if (m_general_allocator)
forked->m_general_allocator = MUST(m_general_allocator->clone(forked->page_table()));
ASSERT(this == &Process::current());
Thread* thread = MUST(Thread::current().clone(forked, rsp, rip));
forked->add_thread(thread);
register_process(forked);
return forked->pid();
}
BAN::ErrorOr<long> Process::sys_exec(BAN::StringView path, const char* const* argv, const char* const* envp)
{
BAN::Vector<BAN::String> str_argv;
for (int i = 0; argv && argv[i]; i++)
TRY(str_argv.emplace_back(argv[i]));
BAN::Vector<BAN::StringView> path_env;
BAN::Vector<BAN::String> str_envp;
for (int i = 0; envp && envp[i]; i++)
{
TRY(str_envp.emplace_back(envp[i]));
if (strncmp(envp[i], "PATH=", 5) == 0)
path_env = TRY(BAN::StringView(envp[i]).substring(5).split(':'));
}
BAN::String working_directory;
{
LockGuard _(m_lock);
TRY(working_directory.append(m_working_directory));
}
auto elf = TRY(load_elf_for_exec(m_credentials, path, working_directory, path_env));
LockGuard lock_guard(m_lock);
m_fixed_width_allocators.clear();
m_general_allocator.clear();
for (auto* range : m_mapped_ranges)
delete range;
m_mapped_ranges.clear();
load_elf_to_memory(*elf);
m_userspace_info.entry = elf->file_header_native().e_entry;
// NOTE: we clear the elf since we don't need the memory anymore
elf.clear();
ASSERT(m_threads.size() == 1);
ASSERT(&Process::current() == this);
{
LockGuard _(page_table());
m_userspace_info.argv = (char**)MUST(sys_alloc(sizeof(char**) * (str_argv.size() + 1)));
for (size_t i = 0; i < str_argv.size(); i++)
{
m_userspace_info.argv[i] = (char*)MUST(sys_alloc(str_argv[i].size() + 1));
memcpy(m_userspace_info.argv[i], str_argv[i].data(), str_argv[i].size());
m_userspace_info.argv[i][str_argv[i].size()] = '\0';
}
m_userspace_info.argv[str_argv.size()] = nullptr;
m_userspace_info.envp = (char**)MUST(sys_alloc(sizeof(char**) * (str_envp.size() + 1)));
for (size_t i = 0; i < str_envp.size(); i++)
{
m_userspace_info.envp[i] = (char*)MUST(sys_alloc(str_envp[i].size() + 1));
memcpy(m_userspace_info.envp[i], str_envp[i].data(), str_envp[i].size());
m_userspace_info.envp[i][str_envp[i].size()] = '\0';
}
m_userspace_info.envp[str_envp.size()] = nullptr;
}
m_userspace_info.argc = str_argv.size();
// NOTE: These must be manually cleared since this function won't return after this point
str_argv.clear();
str_envp.clear();
CriticalScope _;
lock_guard.~LockGuard();
m_threads.front()->setup_exec();
Scheduler::get().execute_current_thread();
ASSERT_NOT_REACHED();
}
int Process::block_until_exit()
{
ASSERT(s_process_lock.is_locked());
ASSERT(this != &Process::current());
s_process_lock.unlock();
m_lock.lock();
m_exit_status.waiting++;
while (!m_exit_status.exited)
{
m_lock.unlock();
m_exit_status.semaphore.block();
m_lock.lock();
}
int ret = m_exit_status.exit_code;
m_exit_status.waiting--;
m_lock.unlock();
s_process_lock.lock();
return ret;
}
BAN::ErrorOr<long> Process::sys_wait(pid_t pid, int* stat_loc, int options)
{
Process* target = nullptr;
// FIXME: support options
if (options)
return BAN::Error::from_errno(EINVAL);
LockGuard _(s_process_lock);
for (auto* process : s_processes)
if (process->pid() == pid)
target = process;
if (target == nullptr)
return BAN::Error::from_errno(ECHILD);
pid_t ret = target->pid();
*stat_loc = target->block_until_exit();
return ret;
}
BAN::ErrorOr<long> Process::sys_sleep(int seconds)
{
PIT::sleep(seconds * 1000);
return 0;
}
BAN::ErrorOr<long> Process::sys_setenvp(char** envp)
{
LockGuard _(m_lock);
m_userspace_info.envp = envp;
return 0;
}
void Process::load_elf_to_memory(LibELF::ELF& elf)
{
ASSERT(elf.is_native());
auto& elf_file_header = elf.file_header_native();
for (size_t i = 0; i < elf_file_header.e_phnum; i++)
{
auto& elf_program_header = elf.program_header_native(i);
switch (elf_program_header.p_type)
{
case LibELF::PT_NULL:
break;
case LibELF::PT_LOAD:
{
uint8_t flags = PageTable::Flags::UserSupervisor | PageTable::Flags::Present;
if (elf_program_header.p_flags & LibELF::PF_W)
flags |= PageTable::Flags::ReadWrite;
size_t page_start = elf_program_header.p_vaddr / PAGE_SIZE;
size_t page_end = BAN::Math::div_round_up<size_t>(elf_program_header.p_vaddr + elf_program_header.p_memsz, PAGE_SIZE);
size_t page_count = page_end - page_start;
page_table().lock();
if (!page_table().is_range_free(page_start * PAGE_SIZE, page_count * PAGE_SIZE))
{
page_table().debug_dump();
Kernel::panic("vaddr {8H}-{8H} not free {8H}-{8H}",
page_start * PAGE_SIZE,
page_start * PAGE_SIZE + page_count * PAGE_SIZE
);
}
{
LockGuard _(m_lock);
MUST(m_mapped_ranges.push_back(VirtualRange::create(page_table(), page_start * PAGE_SIZE, page_count * PAGE_SIZE, flags)));
m_mapped_ranges.back()->set_zero();
m_mapped_ranges.back()->copy_from(elf_program_header.p_vaddr % PAGE_SIZE, elf.data() + elf_program_header.p_offset, elf_program_header.p_filesz);
}
page_table().unlock();
break;
}
default:
ASSERT_NOT_REACHED();
}
}
}
BAN::ErrorOr<long> Process::sys_open(BAN::StringView path, int flags)
{
if (flags & ~(O_RDONLY | O_WRONLY | O_NOFOLLOW | O_SEARCH))
return BAN::Error::from_errno(ENOTSUP);
BAN::String absolute_path = TRY(absolute_path_of(path));
auto file = TRY(VirtualFileSystem::get().file_from_absolute_path(m_credentials, absolute_path, flags));
LockGuard _(m_lock);
int fd = TRY(get_free_fd());
auto& open_file_description = m_open_files[fd];
open_file_description.inode = file.inode;
open_file_description.path = BAN::move(file.canonical_path);
open_file_description.offset = 0;
open_file_description.flags = flags;
return fd;
}
BAN::ErrorOr<long> Process::sys_openat(int fd, BAN::StringView path, int flags)
{
BAN::String absolute_path;
{
LockGuard _(m_lock);
TRY(validate_fd(fd));
TRY(absolute_path.append(open_file_description(fd).path));
}
TRY(absolute_path.push_back('/'));
TRY(absolute_path.append(path));
return sys_open(absolute_path, flags);
}
BAN::ErrorOr<long> Process::sys_close(int fd)
{
LockGuard _(m_lock);
TRY(validate_fd(fd));
auto& open_file_description = this->open_file_description(fd);
open_file_description.inode = nullptr;
return 0;
}
BAN::ErrorOr<long> Process::sys_read(int fd, void* buffer, size_t count)
{
OpenFileDescription open_fd_copy;
{
LockGuard _(m_lock);
TRY(validate_fd(fd));
open_fd_copy = open_file_description(fd);
}
if (!(open_fd_copy.flags & O_RDONLY))
return BAN::Error::from_errno(EBADF);
size_t nread = TRY(open_fd_copy.inode->read(open_fd_copy.offset, buffer, count));
{
LockGuard _(m_lock);
MUST(validate_fd(fd));
open_file_description(fd).offset += nread;
}
return nread;
}
BAN::ErrorOr<long> Process::sys_write(int fd, const void* buffer, size_t count)
{
OpenFileDescription open_fd_copy;
{
LockGuard _(m_lock);
TRY(validate_fd(fd));
open_fd_copy = open_file_description(fd);
}
if (!(open_fd_copy.flags & O_WRONLY))
return BAN::Error::from_errno(EBADF);
size_t nwrite = TRY(open_fd_copy.inode->write(open_fd_copy.offset, buffer, count));
{
LockGuard _(m_lock);
MUST(validate_fd(fd));
open_file_description(fd).offset += nwrite;
}
return nwrite;
}
BAN::ErrorOr<long> Process::sys_seek(int fd, off_t offset, int whence)
{
LockGuard _(m_lock);
TRY(validate_fd(fd));
auto& open_fd = open_file_description(fd);
off_t new_offset = 0;
switch (whence)
{
case SEEK_CUR:
new_offset = open_fd.offset + offset;
break;
case SEEK_END:
new_offset = open_fd.inode->size() - offset;
break;
case SEEK_SET:
new_offset = offset;
break;
default:
return BAN::Error::from_errno(EINVAL);
}
if (new_offset < 0)
return BAN::Error::from_errno(EINVAL);
open_fd.offset = new_offset;
return 0;
}
BAN::ErrorOr<long> Process::sys_tell(int fd)
{
LockGuard _(m_lock);
TRY(validate_fd(fd));
return open_file_description(fd).offset;
}
BAN::ErrorOr<long> Process::sys_creat(BAN::StringView path, mode_t mode)
{
auto absolute_path = TRY(absolute_path_of(path));
size_t index;
for (index = absolute_path.size(); index > 0; index--)
if (absolute_path[index - 1] == '/')
break;
auto directory = absolute_path.sv().substring(0, index);
auto file_name = absolute_path.sv().substring(index);
auto parent_file = TRY(VirtualFileSystem::get().file_from_absolute_path(m_credentials, directory, O_WRONLY));
TRY(parent_file.inode->create_file(file_name, mode));
return 0;
}
BAN::ErrorOr<void> Process::mount(BAN::StringView source, BAN::StringView target)
{
BAN::String absolute_source, absolute_target;
{
LockGuard _(m_lock);
absolute_source = TRY(absolute_path_of(source));
absolute_target = TRY(absolute_path_of(target));
}
TRY(VirtualFileSystem::get().mount(m_credentials, absolute_source, absolute_target));
return {};
}
BAN::ErrorOr<long> Process::sys_fstat(int fd, struct stat* out)
{
OpenFileDescription open_fd_copy;
{
LockGuard _(m_lock);
TRY(validate_fd(fd));
open_fd_copy = open_file_description(fd);
}
out->st_dev = open_fd_copy.inode->dev();
out->st_ino = open_fd_copy.inode->ino();
out->st_mode = open_fd_copy.inode->mode().mode;
out->st_nlink = open_fd_copy.inode->nlink();
out->st_uid = open_fd_copy.inode->uid();
out->st_gid = open_fd_copy.inode->gid();
out->st_rdev = open_fd_copy.inode->rdev();
out->st_size = open_fd_copy.inode->size();
out->st_atim = open_fd_copy.inode->atime();
out->st_mtim = open_fd_copy.inode->mtime();
out->st_ctim = open_fd_copy.inode->ctime();
out->st_blksize = open_fd_copy.inode->blksize();
out->st_blocks = open_fd_copy.inode->blocks();
return 0;
}
BAN::ErrorOr<long> Process::sys_stat(BAN::StringView path, struct stat* out, int flags)
{
int fd = TRY(sys_open(path, flags));
auto ret = sys_fstat(fd, out);
MUST(sys_close(fd));
return ret;
}
BAN::ErrorOr<long> Process::sys_read_dir_entries(int fd, DirectoryEntryList* list, size_t list_size)
{
OpenFileDescription open_fd_copy;
{
LockGuard _(m_lock);
TRY(validate_fd(fd));
open_fd_copy = open_file_description(fd);
}
TRY(open_fd_copy.inode->read_next_directory_entries(open_fd_copy.offset, list, list_size));
{
LockGuard _(m_lock);
MUST(validate_fd(fd));
open_file_description(fd).offset = open_fd_copy.offset + 1;
}
return 0;
}
BAN::ErrorOr<long> Process::sys_setpwd(const char* path)
{
BAN::String absolute_path;
{
LockGuard _(m_lock);
absolute_path = TRY(absolute_path_of(path));
}
auto file = TRY(VirtualFileSystem::get().file_from_absolute_path(m_credentials, absolute_path, O_SEARCH));
if (!file.inode->mode().ifdir())
return BAN::Error::from_errno(ENOTDIR);
LockGuard _(m_lock);
m_working_directory = BAN::move(file.canonical_path);
return 0;
}
BAN::ErrorOr<long> Process::sys_getpwd(char* buffer, size_t size)
{
LockGuard _(m_lock);
if (size < m_working_directory.size() + 1)
return BAN::Error::from_errno(ERANGE);
memcpy(buffer, m_working_directory.data(), m_working_directory.size());
buffer[m_working_directory.size()] = '\0';
return (long)buffer;
}
static constexpr size_t allocator_size_for_allocation(size_t value)
{
if (value <= 256) {
if (value <= 64)
return 64;
else
return 256;
} else {
if (value <= 1024)
return 1024;
else
return 4096;
}
}
BAN::ErrorOr<long> Process::sys_alloc(size_t bytes)
{
vaddr_t address = 0;
if (bytes <= PAGE_SIZE)
{
// Do fixed width allocation
size_t allocation_size = allocator_size_for_allocation(bytes);
ASSERT(bytes <= allocation_size);
ASSERT(allocation_size <= PAGE_SIZE);
LockGuard _(m_lock);
bool needs_new_allocator { true };
for (auto& allocator : m_fixed_width_allocators)
{
if (allocator->allocation_size() == allocation_size && allocator->allocations() < allocator->max_allocations())
{
address = allocator->allocate();
needs_new_allocator = false;
break;
}
}
if (needs_new_allocator)
{
auto allocator = TRY(FixedWidthAllocator::create(page_table(), allocation_size));
TRY(m_fixed_width_allocators.push_back(BAN::move(allocator)));
address = m_fixed_width_allocators.back()->allocate();
}
}
else
{
LockGuard _(m_lock);
if (!m_general_allocator)
m_general_allocator = TRY(GeneralAllocator::create(page_table(), 0x400000));
address = m_general_allocator->allocate(bytes);
}
if (address == 0)
return BAN::Error::from_errno(ENOMEM);
return address;
}
BAN::ErrorOr<long> Process::sys_free(void* ptr)
{
LockGuard _(m_lock);
for (size_t i = 0; i < m_fixed_width_allocators.size(); i++)
{
auto& allocator = m_fixed_width_allocators[i];
if (allocator->deallocate((vaddr_t)ptr))
{
// TODO: This might be too much. Maybe we should only
// remove allocators when we have low memory... ?
if (allocator->allocations() == 0)
m_fixed_width_allocators.remove(i);
return 0;
}
}
if (m_general_allocator && m_general_allocator->deallocate((vaddr_t)ptr))
return 0;
dwarnln("free called on pointer that was not allocated");
return BAN::Error::from_errno(EINVAL);
}
BAN::ErrorOr<long> Process::sys_termid(char* buffer) const
{
LockGuard _(m_lock);
if (m_tty == nullptr)
buffer[0] = '\0';
strcpy(buffer, "/dev/");
strcpy(buffer + 5, m_tty->name().data());
return 0;
}
BAN::ErrorOr<long> Process::sys_setuid(uid_t uid)
{
if (uid < 0 || uid >= 1'000'000'000)
return BAN::Error::from_errno(EINVAL);
LockGuard _(m_lock);
// If the process has appropriate privileges, setuid() shall set the real user ID, effective user ID, and the saved
// set-user-ID of the calling process to uid.
if (m_credentials.is_superuser())
{
m_credentials.set_euid(uid);
m_credentials.set_ruid(uid);
m_credentials.set_suid(uid);
return 0;
}
// If the process does not have appropriate privileges, but uid is equal to the real user ID or the saved set-user-ID,
// setuid() shall set the effective user ID to uid; the real user ID and saved set-user-ID shall remain unchanged.
if (uid == m_credentials.ruid() || uid == m_credentials.suid())
{
m_credentials.set_euid(uid);
return 0;
}
return BAN::Error::from_errno(EPERM);
}
BAN::ErrorOr<long> Process::sys_setgid(gid_t gid)
{
if (gid < 0 || gid >= 1'000'000'000)
return BAN::Error::from_errno(EINVAL);
LockGuard _(m_lock);
// If the process has appropriate privileges, setgid() shall set the real group ID, effective group ID, and the saved
// set-group-ID of the calling process to gid.
if (m_credentials.is_superuser())
{
m_credentials.set_egid(gid);
m_credentials.set_rgid(gid);
m_credentials.set_sgid(gid);
return 0;
}
// If the process does not have appropriate privileges, but gid is equal to the real group ID or the saved set-group-ID,
// setgid() shall set the effective group ID to gid; the real group ID and saved set-group-ID shall remain unchanged.
if (gid == m_credentials.rgid() || gid == m_credentials.sgid())
{
m_credentials.set_egid(gid);
return 0;
}
return BAN::Error::from_errno(EPERM);
}
BAN::ErrorOr<long> Process::sys_seteuid(uid_t uid)
{
if (uid < 0 || uid >= 1'000'000'000)
return BAN::Error::from_errno(EINVAL);
LockGuard _(m_lock);
// If uid is equal to the real user ID or the saved set-user-ID, or if the process has appropriate privileges, seteuid()
// shall set the effective user ID of the calling process to uid; the real user ID and saved set-user-ID shall remain unchanged.
if (uid == m_credentials.ruid() || uid == m_credentials.suid() || m_credentials.is_superuser())
{
m_credentials.set_euid(uid);
return 0;
}
return BAN::Error::from_errno(EPERM);
}
BAN::ErrorOr<long> Process::sys_setegid(gid_t gid)
{
if (gid < 0 || gid >= 1'000'000'000)
return BAN::Error::from_errno(EINVAL);
LockGuard _(m_lock);
// If gid is equal to the real group ID or the saved set-group-ID, or if the process has appropriate privileges, setegid()
// shall set the effective group ID of the calling process to gid; the real group ID, saved set-group-ID, and any
// supplementary group IDs shall remain unchanged.
if (gid == m_credentials.rgid() || gid == m_credentials.sgid() || m_credentials.is_superuser())
{
m_credentials.set_egid(gid);
return 0;
}
return BAN::Error::from_errno(EPERM);
}
BAN::ErrorOr<long> Process::sys_setreuid(uid_t ruid, uid_t euid)
{
if (ruid == -1 && euid == -1)
return 0;
if (ruid < -1 || ruid >= 1'000'000'000)
return BAN::Error::from_errno(EINVAL);
if (euid < -1 || euid >= 1'000'000'000)
return BAN::Error::from_errno(EINVAL);
// The setreuid() function shall set the real and effective user IDs of the current process to the values specified
// by the ruid and euid arguments. If ruid or euid is -1, the corresponding effective or real user ID of the current
// process shall be left unchanged.
LockGuard _(m_lock);
// A process with appropriate privileges can set either ID to any value.
if (!m_credentials.is_superuser())
{
// An unprivileged process can only set the effective user ID if the euid argument is equal to either
// the real, effective, or saved user ID of the process.
if (euid != -1 && euid != m_credentials.ruid() && euid != m_credentials.euid() && euid == m_credentials.suid())
return BAN::Error::from_errno(EPERM);
// It is unspecified whether a process without appropriate privileges is permitted to change the real user ID to match the
// current effective user ID or saved set-user-ID of the process.
// NOTE: we will allow this
if (ruid != -1 && ruid != m_credentials.ruid() && ruid != m_credentials.euid() && ruid == m_credentials.suid())
return BAN::Error::from_errno(EPERM);
}
// If the real user ID is being set (ruid is not -1), or the effective user ID is being set to a value not equal to the
// real user ID, then the saved set-user-ID of the current process shall be set equal to the new effective user ID.
if (ruid != -1 || euid != m_credentials.ruid())
m_credentials.set_suid(euid);
if (ruid != -1)
m_credentials.set_ruid(ruid);
if (euid != -1)
m_credentials.set_euid(euid);
return 0;
}
BAN::ErrorOr<long> Process::sys_setregid(gid_t rgid, gid_t egid)
{
if (rgid == -1 && egid == -1)
return 0;
if (rgid < -1 || rgid >= 1'000'000'000)
return BAN::Error::from_errno(EINVAL);
if (egid < -1 || egid >= 1'000'000'000)
return BAN::Error::from_errno(EINVAL);
// The setregid() function shall set the real and effective group IDs of the calling process.
// If rgid is -1, the real group ID shall not be changed; if egid is -1, the effective group ID shall not be changed.
// The real and effective group IDs may be set to different values in the same call.
LockGuard _(m_lock);
// Only a process with appropriate privileges can set the real group ID and the effective group ID to any valid value.
if (!m_credentials.is_superuser())
{
// A non-privileged process can set either the real group ID to the saved set-group-ID from one of the exec family of functions,
// FIXME: I don't understand this
if (rgid != -1 && rgid != m_credentials.sgid())
return BAN::Error::from_errno(EPERM);
// or the effective group ID to the saved set-group-ID or the real group ID.
if (egid != -1 && egid != m_credentials.sgid() && egid != m_credentials.rgid())
return BAN::Error::from_errno(EPERM);
}
// If the real group ID is being set (rgid is not -1), or the effective group ID is being set to a value not equal to the
// real group ID, then the saved set-group-ID of the current process shall be set equal to the new effective group ID.
if (rgid != -1 || egid != m_credentials.rgid())
m_credentials.set_sgid(egid);
if (rgid != -1)
m_credentials.set_rgid(rgid);
if (egid != -1)
m_credentials.set_egid(egid);
return 0;
}
BAN::ErrorOr<BAN::String> Process::absolute_path_of(BAN::StringView path) const
{
if (path.empty() || path == "."sv)
{
LockGuard _(m_lock);
return m_working_directory;
}
BAN::String absolute_path;
if (path.front() != '/')
{
LockGuard _(m_lock);
TRY(absolute_path.append(m_working_directory));
}
if (!absolute_path.empty() && absolute_path.back() != '/')
TRY(absolute_path.push_back('/'));
TRY(absolute_path.append(path));
return absolute_path;
}
BAN::ErrorOr<void> Process::validate_fd(int fd)
{
ASSERT(m_lock.is_locked());
if (fd < 0 || m_open_files.size() <= (size_t)fd || !m_open_files[fd].inode)
return BAN::Error::from_errno(EBADF);
return {};
}
Process::OpenFileDescription& Process::open_file_description(int fd)
{
ASSERT(m_lock.is_locked());
MUST(validate_fd(fd));
return m_open_files[fd];
}
BAN::ErrorOr<int> Process::get_free_fd()
{
ASSERT(m_lock.is_locked());
for (size_t fd = 0; fd < m_open_files.size(); fd++)
if (!m_open_files[fd].inode)
return fd;
TRY(m_open_files.push_back({}));
return m_open_files.size() - 1;
}
}
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