Start adding a basic /proc filesystem and a "ps" utility.

Kernel/Makefile

@@ -21,7 +21,8 @@ KERNEL_OBJS = \
        MemoryManager.o \
        Console.o \
        IRQHandler.o \
-       kprintf.o
+       kprintf.o \
+       ProcFileSystem.o
 
 VFS_OBJS = \
     ../VirtualFileSystem/DiskDevice.o \
@@ -35,7 +36,8 @@ VFS_OBJS = \
     ../VirtualFileSystem/Ext2FileSystem.o \
     ../VirtualFileSystem/InodeIdentifier.o \
     ../VirtualFileSystem/VirtualFileSystem.o \
-    ../VirtualFileSystem/FileHandle.o
+    ../VirtualFileSystem/FileHandle.o \
+    ../VirtualFileSystem/SyntheticFileSystem.o
 
 ELFLOADER_OBJS = \
     ../ELFLoader/ELFImage.o \

Kernel/ProcFileSystem.cpp

@@ -0,0 +1,29 @@
+#include "ProcFileSystem.h"
+#include <AK/StdLib.h>
+
+RetainPtr<ProcFileSystem> ProcFileSystem::create()
+{
+    return adopt(*new ProcFileSystem);
+}
+
+ProcFileSystem::ProcFileSystem()
+{
+}
+
+ProcFileSystem::~ProcFileSystem()
+{
+}
+
+bool ProcFileSystem::initialize()
+{
+    SyntheticFileSystem::initialize();
+    addFile(createGeneratedFile("summary", [] {
+        return String("Process summary!").toByteBuffer();
+    }));
+    return true;
+}
+
+const char* ProcFileSystem::className() const
+{
+    return "procfs";
+}

Kernel/ProcFileSystem.h

@@ -0,0 +1,17 @@
+#pragma once
+
+#include <AK/Types.h>
+#include <VirtualFileSystem/SyntheticFileSystem.h>
+
+class ProcFileSystem final : public SyntheticFileSystem {
+public:
+    virtual ~ProcFileSystem() override;
+    static RetainPtr<ProcFileSystem> create();
+
+    virtual bool initialize() override;
+    virtual const char* className() const override;
+
+private:
+    ProcFileSystem();
+};
+

Kernel/Task.cpp

@@ -645,7 +645,9 @@ FileHandle* Task::openFile(String&& path)
 {
     auto handle = VirtualFileSystem::the().open(move(path));
     if (!handle) {
+#ifdef DEBUG_IO
         kprintf("vfs::open() failed\n");
+#endif
         return nullptr;
     }
     handle->setFD(m_fileHandles.size());

Kernel/init.cpp

@@ -25,6 +25,7 @@
 #include "MemoryManager.h"
 #include <ELFLoader/ELFLoader.h>
 #include "Console.h"
+#include "ProcFileSystem.h"
 
 #define TEST_VFS
 //#define TEST_ELF_LOADER
@@ -132,7 +133,9 @@ static void init_stage2()
 
     vfs->mountRoot(e2fs.copyRef());
 
-    //vfs->listDirectory("/");
+    auto procfs = ProcFileSystem::create();
+    procfs->initialize();
+    vfs->mount(procfs.copyRef(), "/proc");
 
     {
         auto motdFile = vfs->open("/motd.txt");

Kernel/sync-sh

@@ -1,5 +1,7 @@
 mkdir mnt
 mount -o loop _fs_contents mnt/
 cp ../Userland/sh mnt/bin/sh
+cp ../Userland/id mnt/bin/id
+cp ../Userland/ps mnt/bin/ps
 umount mnt
 sync