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Kernel: Make sure processes always start out with fds 0, 1 and 2 open.

If we don't have a TTY for the process, fall back to /dev/null.
This commit is contained in:
Andreas Kling 2019-02-12 11:25:25 +01:00
parent 7def86c86d
commit 111589a558
5 changed files with 46 additions and 15 deletions

View file

@ -3,9 +3,18 @@
#include <AK/StdLibExtras.h>
#include <AK/kstdio.h>
static NullDevice* s_the;
NullDevice& NullDevice::the()
{
ASSERT(s_the);
return *s_the;
}
NullDevice::NullDevice()
: CharacterDevice(1, 3)
{
s_the = this;
}
NullDevice::~NullDevice()

View file

@ -8,6 +8,8 @@ public:
NullDevice();
virtual ~NullDevice() override;
static NullDevice& the();
private:
// ^CharacterDevice
virtual ssize_t read(Process&, byte* buffer, size_t bufferSize) override;

View file

@ -6,6 +6,7 @@
#include "system.h"
#include <Kernel/FileDescriptor.h>
#include <Kernel/VirtualFileSystem.h>
#include <Kernel/NullDevice.h>
#include "ELFLoader.h"
#include "MemoryManager.h"
#include "i8253.h"
@ -623,12 +624,11 @@ Process::Process(String&& name, uid_t uid, gid_t gid, pid_t ppid, RingLevel ring
}
} else {
m_fds.resize(m_max_open_file_descriptors);
if (tty) {
int error;
m_fds[0].set(tty->open(error, O_RDONLY));
m_fds[1].set(tty->open(error, O_WRONLY));
m_fds[2].set(tty->open(error, O_WRONLY));
}
auto& device_to_use_as_tty = tty ? (CharacterDevice&)*tty : NullDevice::the();
int error;
m_fds[0].set(device_to_use_as_tty.open(error, O_RDONLY));
m_fds[1].set(device_to_use_as_tty.open(error, O_WRONLY));
m_fds[2].set(device_to_use_as_tty.open(error, O_WRONLY));
}
if (fork_parent)

View file

@ -43,6 +43,7 @@ VirtualConsole* tty3;
Keyboard* keyboard;
PS2MouseDevice* ps2mouse;
GUIEventDevice* gui_event_device;
NullDevice* dev_null;
VFS* vfs;
#ifdef STRESS_TEST_SPAWNING
@ -72,7 +73,6 @@ static void init_stage2()
auto dev_zero = make<ZeroDevice>();
vfs->register_character_device(*dev_zero);
auto dev_null = make<NullDevice>();
vfs->register_character_device(*dev_null);
auto dev_full = make<FullDevice>();
@ -162,6 +162,7 @@ void init()
keyboard = new Keyboard;
ps2mouse = new PS2MouseDevice;
gui_event_device = new GUIEventDevice;
dev_null = new NullDevice;
VirtualConsole::initialize();
tty0 = new VirtualConsole(0, VirtualConsole::AdoptCurrentVGABuffer);