ladybird/Kernel/Process.h
Andreas Kling 8accc92c3c Implement fork()!
This is quite cool! The syscall entry point plumbs the register dump
down to sys$fork(), which uses it to set up the child process's TSS
in order to resume execution right after the int 0x80 fork() call. :^)

This works pretty well, although there is some problem with the kernel
alias mappings used to clone the parent process's regions. If I disable
the MM::release_page_directory() code, there's no problem. Probably there's
a premature freeing of a physical page somehow.
2018-11-02 20:41:58 +01:00

248 lines
7.5 KiB
C++

#pragma once
#include "types.h"
#include "InlineLinkedList.h"
#include <AK/String.h>
#include "TSS.h"
#include <AK/Vector.h>
#include "i386.h"
#include <VirtualFileSystem/VirtualFileSystem.h>
#include "TTY.h"
class FileHandle;
class PageDirectory;
class Region;
class Subregion;
class Zone;
class Process : public InlineLinkedListNode<Process> {
friend class InlineLinkedListNode<Process>;
public:
static Process* createKernelProcess(void (*entry)(), String&& name);
static Process* createUserProcess(const String& path, uid_t, gid_t, pid_t parentPID, int& error, const char** args = nullptr, TTY* = nullptr);
~Process();
static Vector<Process*> allProcesses();
enum State {
Invalid = 0,
Runnable = 1,
Running = 2,
Terminated = 3,
Crashing = 4,
Exiting = 5,
BeingInspected = 6,
BlockedSleep = 7,
BlockedWait = 8,
BlockedRead = 9,
};
enum RingLevel {
Ring0 = 0,
Ring3 = 3,
};
bool isRing0() const { return m_ring == Ring0; }
bool isRing3() const { return m_ring == Ring3; }
static Process* fromPID(pid_t);
static Process* kernelProcess();
const String& name() const { return m_name; }
pid_t pid() const { return m_pid; }
pid_t sid() const { return m_sid; }
pid_t pgid() const { return m_pgid; }
DWORD ticks() const { return m_ticks; }
WORD selector() const { return m_farPtr.selector; }
TSS32& tss() { return m_tss; }
State state() const { return m_state; }
uid_t uid() const { return m_uid; }
uid_t gid() const { return m_gid; }
pid_t parentPID() const { return m_parentPID; }
const FarPtr& farPtr() const { return m_farPtr; }
FileHandle* fileHandleIfExists(int fd);
static void doHouseKeeping();
void block(Process::State);
void unblock();
void setWakeupTime(DWORD t) { m_wakeupTime = t; }
DWORD wakeupTime() const { return m_wakeupTime; }
static void for_each_in_pgrp(pid_t pgid, Function<void(Process&)>);
static void prepForIRETToNewProcess();
bool tick() { ++m_ticks; return --m_ticksLeft; }
void setTicksLeft(DWORD t) { m_ticksLeft = t; }
void setSelector(WORD s) { m_farPtr.selector = s; }
void set_state(State s) { m_state = s; }
pid_t sys$setsid();
pid_t sys$getsid(pid_t);
int sys$setpgid(pid_t pid, pid_t pgid);
pid_t sys$getpgrp();
pid_t sys$getpgid(pid_t);
pid_t sys$tcgetpgrp(int fd);
int sys$tcsetpgrp(int fd, pid_t pgid);
uid_t sys$getuid();
gid_t sys$getgid();
pid_t sys$getpid();
int sys$open(const char* path, int options);
int sys$close(int fd);
ssize_t sys$read(int fd, void* outbuf, size_t nread);
ssize_t sys$write(int fd, const void*, size_t);
int sys$lstat(const char*, Unix::stat*);
int sys$stat(const char*, Unix::stat*);
int sys$lseek(int fd, off_t, int whence);
int sys$kill(pid_t pid, int sig);
int sys$geterror() { return m_error; }
void sys$exit(int status);
int sys$spawn(const char* path, const char** args);
pid_t sys$waitpid(pid_t, int* wstatus, int options);
void* sys$mmap(void*, size_t size);
int sys$munmap(void*, size_t size);
int sys$set_mmap_name(void*, size_t, const char*);
int sys$get_dir_entries(int fd, void*, size_t);
int sys$getcwd(char*, size_t);
int sys$chdir(const char*);
int sys$sleep(unsigned seconds);
int sys$gettimeofday(timeval*);
int sys$gethostname(char* name, size_t length);
int sys$get_arguments(int* argc, char*** argv);
int sys$get_environment(char*** environ);
int sys$uname(utsname*);
int sys$readlink(const char*, char*, size_t);
int sys$ttyname_r(int fd, char*, size_t);
pid_t sys$fork(RegisterDump&);
static void initialize();
static void processDidCrash(Process*);
const TTY* tty() const { return m_tty; }
size_t regionCount() const { return m_regions.size(); }
const Vector<RetainPtr<Region>>& regions() const { return m_regions; }
size_t subregionCount() const { return m_regions.size(); }
const Vector<OwnPtr<Subregion>>& subregions() const { return m_subregions; }
void dumpRegions();
void didSchedule() { ++m_timesScheduled; }
dword timesScheduled() const { return m_timesScheduled; }
pid_t waitee() const { return m_waitee; }
dword framePtr() const { return m_tss.ebp; }
dword stackPtr() const { return m_tss.esp; }
dword stackTop() const { return m_tss.ss == 0x10 ? m_stackTop0 : m_stackTop3; }
bool isValidAddressForKernel(LinearAddress) const;
bool validate_user_read(LinearAddress) const;
bool validate_user_write(LinearAddress) const;
InodeIdentifier cwdInode() const { return m_cwd ? m_cwd->inode : InodeIdentifier(); }
InodeIdentifier executableInode() const { return m_executable ? m_executable->inode : InodeIdentifier(); }
size_t number_of_open_file_descriptors() const;
size_t max_open_file_descriptors() const { return m_max_open_file_descriptors; }
FileHandle* file_descriptor(size_t i) { return m_file_descriptors[i].ptr(); }
const FileHandle* file_descriptor(size_t i) const { return m_file_descriptors[i].ptr(); }
void send_signal(int signal, Process* sender);
Process* fork(RegisterDump&);
private:
friend class MemoryManager;
friend bool scheduleNewProcess();
Process(String&& name, uid_t, gid_t, pid_t parentPID, RingLevel, RetainPtr<VirtualFileSystem::Node>&& cwd = nullptr, RetainPtr<VirtualFileSystem::Node>&& executable = nullptr, TTY* = nullptr, Process* fork_parent = nullptr);
void allocateLDT();
PageDirectory* m_page_directory { nullptr };
Process* m_prev { nullptr };
Process* m_next { nullptr };
String m_name;
void (*m_entry)() { nullptr };
pid_t m_pid { 0 };
uid_t m_uid { 0 };
gid_t m_gid { 0 };
pid_t m_sid { 0 };
pid_t m_pgid { 0 };
DWORD m_ticks { 0 };
DWORD m_ticksLeft { 0 };
DWORD m_stackTop0 { 0 };
DWORD m_stackTop3 { 0 };
FarPtr m_farPtr;
State m_state { Invalid };
DWORD m_wakeupTime { 0 };
TSS32 m_tss;
Vector<OwnPtr<FileHandle>> m_file_descriptors;
RingLevel m_ring { Ring0 };
int m_error { 0 };
void* m_kernelStack { nullptr };
dword m_timesScheduled { 0 };
pid_t m_waitee { -1 };
int m_waiteeStatus { 0 };
int m_fdBlockedOnRead { -1 };
size_t m_max_open_file_descriptors { 16 };
RetainPtr<VirtualFileSystem::Node> m_cwd;
RetainPtr<VirtualFileSystem::Node> m_executable;
TTY* m_tty { nullptr };
Region* allocateRegion(size_t, String&& name);
Region* allocateRegion(size_t, String&& name, LinearAddress);
bool deallocateRegion(Region& region);
Region* regionFromRange(LinearAddress, size_t);
Vector<RetainPtr<Region>> m_regions;
Vector<OwnPtr<Subregion>> m_subregions;
// FIXME: Implement some kind of ASLR?
LinearAddress m_nextRegion;
pid_t m_parentPID { 0 };
static void notify_waiters(pid_t waitee, int exit_status, int signal);
Vector<String> m_arguments;
Vector<String> m_initialEnvironment;
};
class ProcessInspectionScope {
public:
ProcessInspectionScope(Process& process)
: m_process(process)
, m_original_state(process.state())
{
m_process.set_state(Process::BeingInspected);
}
~ProcessInspectionScope()
{
m_process.set_state(m_original_state);
}
private:
Process& m_process;
Process::State m_original_state { Process::Invalid };
};
extern void yield();
extern bool scheduleNewProcess();
extern void switchNow();
extern void block(Process::State);
extern void sleep(DWORD ticks);
extern Process* current;