From c99f8af66da3464447e3f310cddb21f63d59292a Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Fri, 16 Nov 2018 13:11:21 +0100
Subject: [PATCH] Add ioctl() and reimplement tcsetpgrp/tcsetpgrp as ioctls.

---
 Kernel/Process.cpp                    | 27 +++------------------------
 Kernel/Process.h                      |  3 +--
 Kernel/Syscall.cpp                    |  6 ++----
 Kernel/Syscall.h                      | 11 +++++------
 Kernel/TTY.cpp                        | 21 +++++++++++++++++++++
 Kernel/TTY.h                          |  3 +++
 LibC/Makefile                         |  1 +
 LibC/ioctl.cpp                        | 19 +++++++++++++++++++
 LibC/stdarg.h                         |  8 ++++----
 LibC/sys/ioctl.h                      | 10 ++++++++++
 LibC/sys/ioctl_numbers.h              |  7 +++++++
 LibC/termcap.cpp                      |  1 +
 LibC/unistd.cpp                       |  7 +++----
 VirtualFileSystem/CharacterDevice.cpp |  6 ++++++
 VirtualFileSystem/CharacterDevice.h   |  6 +++++-
 VirtualFileSystem/FileDescriptor.h    |  3 +++
 16 files changed, 94 insertions(+), 45 deletions(-)
 create mode 100644 LibC/ioctl.cpp
 create mode 100644 LibC/sys/ioctl_numbers.h

diff --git a/Kernel/Process.cpp b/Kernel/Process.cpp
index 3df32e6abb1..5915872b303 100644
--- a/Kernel/Process.cpp
+++ b/Kernel/Process.cpp
@@ -1586,35 +1586,14 @@ int Process::sys$tcsetattr(int fd, int optional_actions, const Unix::termios* tp
     return 0;
 }
 
-pid_t Process::sys$tcgetpgrp(int fd)
+int Process::sys$ioctl(int fd, unsigned request, unsigned arg)
 {
     auto* descriptor = file_descriptor(fd);
     if (!descriptor)
         return -EBADF;
-    if (!descriptor->isTTY())
+    if (!descriptor->is_character_device())
         return -ENOTTY;
-    auto& tty = *descriptor->tty();
-    if (&tty != m_tty)
-        return -ENOTTY;
-    return tty.pgid();
-}
-
-int Process::sys$tcsetpgrp(int fd, pid_t pgid)
-{
-    if (pgid < 0)
-        return -EINVAL;
-    if (get_sid_from_pgid(pgid) != m_sid)
-        return -EINVAL;
-    auto* descriptor = file_descriptor(fd);
-    if (!descriptor)
-        return -EBADF;
-    if (!descriptor->isTTY())
-        return -ENOTTY;
-    auto& tty = *descriptor->tty();
-    if (&tty != m_tty)
-        return -ENOTTY;
-    tty.set_pgid(pgid);
-    return 0;
+    return descriptor->character_device()->ioctl(*this, request, arg);
 }
 
 int Process::sys$getdtablesize()
diff --git a/Kernel/Process.h b/Kernel/Process.h
index a354d00285d..f15afd1ae99 100644
--- a/Kernel/Process.h
+++ b/Kernel/Process.h
@@ -118,8 +118,6 @@ public:
     int sys$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();
     uid_t sys$geteuid();
@@ -175,6 +173,7 @@ public:
     int sys$fcntl(int fd, int cmd, dword extra_arg);
     int sys$tcgetattr(int fd, Unix::termios*);
     int sys$tcsetattr(int fd, int optional_actions, const Unix::termios*);
+    int sys$ioctl(int fd, unsigned request, unsigned arg);
 
     static void initialize();
 
diff --git a/Kernel/Syscall.cpp b/Kernel/Syscall.cpp
index 557725fc15d..95f41e0c824 100644
--- a/Kernel/Syscall.cpp
+++ b/Kernel/Syscall.cpp
@@ -125,10 +125,6 @@ static DWORD handle(RegisterDump& regs, DWORD function, DWORD arg1, DWORD arg2,
         return current->sys$getpgid((pid_t)arg1);
     case Syscall::SC_getpgrp:
         return current->sys$getpgrp();
-    case Syscall::SC_tcgetpgrp:
-        return current->sys$tcgetpgrp((int)arg1);
-    case Syscall::SC_tcsetpgrp:
-        return current->sys$tcsetpgrp((int)arg1, (pid_t)arg2);
     case Syscall::SC_fork:
         return current->sys$fork(regs);
     case Syscall::SC_execve:
@@ -179,6 +175,8 @@ static DWORD handle(RegisterDump& regs, DWORD function, DWORD arg1, DWORD arg2,
         return current->sys$tcgetattr((int)arg1, (Unix::termios*)arg2);
     case Syscall::SC_tcsetattr:
         return current->sys$tcsetattr((int)arg1, (int)arg2, (const Unix::termios*)arg3);
+    case Syscall::SC_ioctl:
+        return current->sys$ioctl((int)arg1, (unsigned)arg2, (unsigned)arg3);
     default:
         kprintf("<%u> int0x80: Unknown function %x requested {%x, %x, %x}\n", current->pid(), function, arg1, arg2, arg3);
         break;
diff --git a/Kernel/Syscall.h b/Kernel/Syscall.h
index a9346ff2112..65ce348950e 100644
--- a/Kernel/Syscall.h
+++ b/Kernel/Syscall.h
@@ -37,8 +37,6 @@
     __ENUMERATE_SYSCALL(getpgid) \
     __ENUMERATE_SYSCALL(setpgid) \
     __ENUMERATE_SYSCALL(getpgrp) \
-    __ENUMERATE_SYSCALL(tcsetpgrp) \
-    __ENUMERATE_SYSCALL(tcgetpgrp) \
     __ENUMERATE_SYSCALL(fork) \
     __ENUMERATE_SYSCALL(execve) \
     __ENUMERATE_SYSCALL(geteuid) \
@@ -66,6 +64,7 @@
     __ENUMERATE_SYSCALL(fcntl) \
     __ENUMERATE_SYSCALL(tcsetattr) \
     __ENUMERATE_SYSCALL(tcgetattr) \
+    __ENUMERATE_SYSCALL(ioctl) \
 
 
 #define DO_SYSCALL_A0(function) Syscall::invoke((dword)(function))
@@ -104,28 +103,28 @@ struct SC_mmap_params {
 
 void initialize();
 
-inline dword invoke(dword function)
+inline dword invoke(Function function)
 {
     dword result;
     asm volatile("int $0x80":"=a"(result):"a"(function):"memory");
     return result;
 }
 
-inline dword invoke(dword function, dword arg1)
+inline dword invoke(Function function, dword arg1)
 {
     dword result;
     asm volatile("int $0x80":"=a"(result):"a"(function),"d"(arg1):"memory");
     return result;
 }
 
-inline dword invoke(dword function, dword arg1, dword arg2)
+inline dword invoke(Function function, dword arg1, dword arg2)
 {
     dword result;
     asm volatile("int $0x80":"=a"(result):"a"(function),"d"(arg1),"c"(arg2):"memory");
     return result;
 }
 
-inline dword invoke(dword function, dword arg1, dword arg2, dword arg3)
+inline dword invoke(Function function, dword arg1, dword arg2, dword arg3)
 {
     dword result;
     asm volatile("int $0x80":"=a"(result):"a"(function),"d"(arg1),"c"(arg2),"b"(arg3):"memory");
diff --git a/Kernel/TTY.cpp b/Kernel/TTY.cpp
index 3fc553a8bd6..6b2f2fb34c8 100644
--- a/Kernel/TTY.cpp
+++ b/Kernel/TTY.cpp
@@ -1,6 +1,8 @@
 #include "TTY.h"
 #include "Process.h"
+#include <LibC/errno_numbers.h>
 #include <LibC/signal_numbers.h>
+#include <LibC/sys/ioctl_numbers.h>
 
 TTY::TTY(unsigned major, unsigned minor)
     : CharacterDevice(major, minor)
@@ -66,3 +68,22 @@ void TTY::set_termios(const Unix::termios& t)
         should_echo_input(),
         should_generate_signals());
 }
+
+int TTY::ioctl(Process& process, unsigned request, unsigned arg)
+{
+    if (process.tty() != this)
+        return -ENOTTY;
+    switch (request) {
+    case TIOCGPGRP:
+        return pgid();
+    case TIOCSPGRP: {
+        // FIXME: Validate pgid fully.
+        pid_t pgid = static_cast<pid_t>(arg);
+        if (pgid < 0)
+            return -EINVAL;
+        set_pgid(arg);
+        return 0;
+    }
+    }
+    return -EINVAL;
+}
diff --git a/Kernel/TTY.h b/Kernel/TTY.h
index e8bce25f736..8018012ce00 100644
--- a/Kernel/TTY.h
+++ b/Kernel/TTY.h
@@ -3,6 +3,8 @@
 #include <VirtualFileSystem/CharacterDevice.h>
 #include <VirtualFileSystem/UnixTypes.h>
 
+class Process;
+
 class TTY : public CharacterDevice {
 public:
     virtual ~TTY() override;
@@ -10,6 +12,7 @@ public:
     virtual ssize_t read(byte*, size_t) override;
     virtual ssize_t write(const byte*, size_t) override;
     virtual bool hasDataAvailableForRead() const override;
+    virtual int ioctl(Process&, unsigned request, unsigned arg) override final;
 
     virtual String ttyName() const = 0;
 
diff --git a/LibC/Makefile b/LibC/Makefile
index bbe6a1136d3..9cabeb8ea6f 100644
--- a/LibC/Makefile
+++ b/LibC/Makefile
@@ -30,6 +30,7 @@ LIBC_OBJS = \
        termios.o \
        ulimit.o \
        qsort.o \
+       ioctl.o \
        entry.o
 
 OBJS = $(AK_OBJS) $(LIBC_OBJS)
diff --git a/LibC/ioctl.cpp b/LibC/ioctl.cpp
new file mode 100644
index 00000000000..dcfc7ce7a41
--- /dev/null
+++ b/LibC/ioctl.cpp
@@ -0,0 +1,19 @@
+#include <errno.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <sys/ioctl.h>
+#include <Kernel/Syscall.h>
+
+extern "C" {
+
+int ioctl(int fd, unsigned request, ...)
+{
+    va_list ap;
+    va_start(ap, request);
+    unsigned arg = va_arg(ap, unsigned);
+    int rc = Syscall::invoke(Syscall::SC_ioctl, (dword)fd, (dword)request, (dword)arg);
+    __RETURN_WITH_ERRNO(rc, rc, -1);
+}
+
+}
+
diff --git a/LibC/stdarg.h b/LibC/stdarg.h
index 724ffb59d57..c58efc85fa0 100644
--- a/LibC/stdarg.h
+++ b/LibC/stdarg.h
@@ -4,11 +4,11 @@
 
 __BEGIN_DECLS
 
-typedef char* va_list;
+typedef __builtin_va_list va_list;
 
-#define va_start(ap, v) ap = (va_list)&v + sizeof(v)
-#define va_arg(ap, t) ((t*)(ap += sizeof(t)))[-1]
-#define va_end(ap) ap = nullptr
+#define va_start(v, l) __builtin_va_start(v, l)
+#define va_end(v) __builtin_va_end(v)
+#define va_arg(v, l) __builtin_va_arg(v, l)
 
 __END_DECLS
 
diff --git a/LibC/sys/ioctl.h b/LibC/sys/ioctl.h
index e69de29bb2d..3a2dcd0b5f2 100644
--- a/LibC/sys/ioctl.h
+++ b/LibC/sys/ioctl.h
@@ -0,0 +1,10 @@
+#pragma once
+
+#include <sys/cdefs.h>
+#include <sys/ioctl_numbers.h>
+
+__BEGIN_DECLS
+
+int ioctl(int fd, unsigned request, ...);
+
+__END_DECLS
diff --git a/LibC/sys/ioctl_numbers.h b/LibC/sys/ioctl_numbers.h
new file mode 100644
index 00000000000..c0c0fe23d70
--- /dev/null
+++ b/LibC/sys/ioctl_numbers.h
@@ -0,0 +1,7 @@
+#pragma once
+
+enum IOCtlNumber {
+    TIOCGPGRP,
+    TIOCSPGRP,
+};
+
diff --git a/LibC/termcap.cpp b/LibC/termcap.cpp
index d422d476975..5c8e9ce0a8d 100644
--- a/LibC/termcap.cpp
+++ b/LibC/termcap.cpp
@@ -108,6 +108,7 @@ char* tgoto(const char* cap, int col, int row)
 int tputs(const char* str, int affcnt, int (*putc)(int))
 {
     printf("%s", str);
+    return 0;
 }
 
 }
diff --git a/LibC/unistd.cpp b/LibC/unistd.cpp
index 09387a5f644..821654494c4 100644
--- a/LibC/unistd.cpp
+++ b/LibC/unistd.cpp
@@ -6,6 +6,7 @@
 #include <grp.h>
 #include <pwd.h>
 #include <stdio.h>
+#include <sys/ioctl.h>
 #include <Kernel/Syscall.h>
 
 extern "C" {
@@ -60,14 +61,12 @@ pid_t setsid()
 
 pid_t tcgetpgrp(int fd)
 {
-    int rc = Syscall::invoke(Syscall::SC_tcgetpgrp, (dword)fd);
-    __RETURN_WITH_ERRNO(rc, rc, -1);
+    return ioctl(fd, TIOCGPGRP);
 }
 
 int tcsetpgrp(int fd, pid_t pgid)
 {
-    int rc = Syscall::invoke(Syscall::SC_tcsetpgrp, (dword)fd, (dword)pgid);
-    __RETURN_WITH_ERRNO(rc, rc, -1);
+    return ioctl(fd, TIOCSPGRP, pgid);
 }
 
 int setpgid(pid_t pid, pid_t pgid)
diff --git a/VirtualFileSystem/CharacterDevice.cpp b/VirtualFileSystem/CharacterDevice.cpp
index 10afe42b1c9..851664ba9be 100644
--- a/VirtualFileSystem/CharacterDevice.cpp
+++ b/VirtualFileSystem/CharacterDevice.cpp
@@ -1,4 +1,5 @@
 #include "CharacterDevice.h"
+#include <LibC/errno_numbers.h>
 
 CharacterDevice::~CharacterDevice()
 {
@@ -8,3 +9,8 @@ RetainPtr<FileDescriptor> CharacterDevice::open(int options)
 {
     return VFS::the().open(*this, options);
 }
+
+int CharacterDevice::ioctl(Process&, unsigned, unsigned)
+{
+    return -ENOTTY;
+}
diff --git a/VirtualFileSystem/CharacterDevice.h b/VirtualFileSystem/CharacterDevice.h
index 47127977dce..3c78a84da53 100644
--- a/VirtualFileSystem/CharacterDevice.h
+++ b/VirtualFileSystem/CharacterDevice.h
@@ -4,6 +4,8 @@
 #include "Limits.h"
 #include "FileDescriptor.h"
 
+class Process;
+
 class CharacterDevice {
 public:
     virtual ~CharacterDevice();
@@ -20,10 +22,12 @@ public:
 
     virtual bool isTTY() const { return false; }
 
+    virtual int ioctl(Process&, unsigned request, unsigned arg);
+
 protected:
     CharacterDevice(unsigned major, unsigned minor) : m_major(major), m_minor(minor) { }
 
 private:
     unsigned m_major { 0 };
-    unsigned m_minor{ 0 };
+    unsigned m_minor { 0 };
 };
diff --git a/VirtualFileSystem/FileDescriptor.h b/VirtualFileSystem/FileDescriptor.h
index eeb2bec9ca9..b5836cf4d3c 100644
--- a/VirtualFileSystem/FileDescriptor.h
+++ b/VirtualFileSystem/FileDescriptor.h
@@ -38,6 +38,9 @@ public:
 
     bool isDirectory() const;
 
+    bool is_character_device() const { return m_vnode && m_vnode->isCharacterDevice(); }
+    CharacterDevice* character_device() { return m_vnode ? m_vnode->characterDevice() : nullptr; }
+
 #ifdef SERENITY
     bool isTTY() const;
     const TTY* tty() const;