apps/CMakeLists.txt

@@ -31,4 +31,3 @@ luna_app(time.cpp time)
 luna_app(ln.cpp ln)
 luna_app(mktemp.cpp mktemp)
 luna_app(sysfuzz.cpp sysfuzz)
-luna_app(pivot_root.cpp pivot_root)

apps/pivot_root.cpp

@@ -1,19 +0,0 @@
-#include <os/ArgumentParser.h>
-#include <sys/syscall.h>
-#include <unistd.h>
-
-Result<int> luna_main(int argc, char** argv)
-{
-    StringView new_root;
-    StringView put_old;
-
-    os::ArgumentParser parser;
-    parser.add_description("Move the current root directory to another directory and replace it with another mount.");
-    parser.add_system_program_info("pivot_root"_sv);
-    parser.add_positional_argument(new_root, "new_root", true);
-    parser.add_positional_argument(put_old, "put_old", true);
-    parser.parse(argc, argv);
-
-    long rc = syscall(SYS_pivot_root, new_root.chars(), put_old.chars());
-    return Result<int>::from_syscall(rc);
-}

kernel/CMakeLists.txt

@@ -44,7 +44,6 @@ set(SOURCES
     src/fs/Pipe.cpp
     src/fs/Mount.cpp
     src/fs/MBR.cpp
-    src/fs/GPT.cpp
     src/fs/tmpfs/FileSystem.cpp
     src/fs/devices/DeviceRegistry.cpp
     src/fs/devices/NullDevice.cpp

kernel/src/fs/GPT.cpp

@@ -1,73 +0,0 @@
-#include "fs/GPT.h"
-#include <luna/CRC32.h>
-
-static const u8 null_guid[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
-
-namespace GPT
-{
-    Result<bool> identify(SharedPtr<Device> device)
-    {
-        if (!device->is_block_device()) return false;
-
-        Header header;
-        // The header is at LBA 1.
-        usize nread = TRY(device->read((u8*)&header, 1 * GPT_SECTOR_SIZE, sizeof(header)));
-        check(nread == sizeof(header));
-
-        if (memcmp(header.signature, GPT_SIGNATURE, GPT_SIGNATURE_LENGTH)) return false;
-
-        kdbgln("gpt: Found GUID partition table on device %s, revision %#.8x, with space for %d partition entries!",
-               device->device_path().chars(), header.revision, header.num_partitions);
-
-        if (header.revision != GPT_REVISION)
-        {
-            kwarnln("gpt: GUID partition table revision not supported!");
-            return false;
-        }
-
-        check(header.hdr_size == 0x5c);
-        check(header.reserved == 0);
-        check(header.this_lba == 1);
-
-#if 0
-        const u32 chksum = checksum_gpt(header);
-
-        if (chksum != header.checksum)
-        {
-            kwarnln("gpt: Header checksum does not match, %#.8x != %#.8x!", chksum, header.checksum);
-            return false;
-        }
-#endif
-
-        u64 partition_table_start = header.partition_table_lba * GPT_SECTOR_SIZE;
-
-        u32 partition_index = 0;
-
-        auto* table = TRY(make_array<PartitionEntry>(header.num_partitions));
-        auto guard = make_scope_guard([table] { delete[] table; });
-
-        nread = TRY(device->read((u8*)table, partition_table_start, sizeof(PartitionEntry) * header.num_partitions));
-        check(nread == sizeof(PartitionEntry) * header.num_partitions);
-
-        for (u32 i = 0; i < header.num_partitions; i++)
-        {
-            PartitionEntry& entry = table[i];
-
-            if (!memcmp(entry.type_guid, null_guid, 16)) continue;
-
-            kdbgln("gpt: Partition entry #%u is active: start=%lu, end=%lu", i, entry.start_lba, entry.end_lba);
-
-            TRY(MBR::PartitionDevice::create(device, entry.start_lba, entry.end_lba - entry.start_lba,
-                                             partition_index++));
-        }
-
-        return true;
-    }
-
-    u32 checksum_gpt(Header header)
-    {
-        header.checksum = 0;
-
-        return CRC32::checksum((u8*)&header, 0x5c);
-    }
-}

kernel/src/fs/GPT.h

@@ -1,43 +0,0 @@
-#pragma once
-#include "fs/MBR.h"
-
-#define GPT_SIGNATURE "EFI PART"
-#define GPT_SIGNATURE_LENGTH 8
-#define GPT_SECTOR_SIZE 512ul
-#define GPT_REVISION 0x00010000
-
-namespace GPT
-{
-    struct [[gnu::packed]] Header
-    {
-        u8 signature[GPT_SIGNATURE_LENGTH];
-        u32 revision;
-        u32 hdr_size;
-        u32 checksum;
-        u32 reserved;
-        u64 this_lba;
-        u64 alternate_lba;
-        u64 first_usable;
-        u64 last_usable;
-        u8 guid[16];
-        u64 partition_table_lba;
-        u32 num_partitions;
-        u32 partition_entry_size;
-        u32 partition_table_checksum;
-        char blank[512 - 0x5c];
-    };
-
-    struct [[gnu::packed]] PartitionEntry
-    {
-        u8 type_guid[16];
-        u8 unique_guid[16];
-        u64 start_lba;
-        u64 end_lba;
-        u64 attributes;
-        char partition_name[72]; // Could be more or less, see Header::partition_entry_size - 0x38 for the actual size.
-    };
-
-    Result<bool> identify(SharedPtr<Device> device);
-
-    u32 checksum_gpt(Header header);
-}

kernel/src/fs/MBR.cpp

@@ -1,6 +1,5 @@
 #include "fs/MBR.h"
 #include "Log.h"
-#include "fs/GPT.h"
 #include <luna/CType.h>
 
 static Result<String> create_partition_name(SharedPtr<Device> host_device, u32 partition_index)
@@ -61,12 +60,6 @@ namespace MBR
 
         u32 partition_index = 0;
 
-        for (int i = 0; i < 4; i++)
-        {
-            const auto& part = hdr.partitions[i];
-            if (part.partition_type == 0xee) return GPT::identify(device);
-        }
-
         for (int i = 0; i < 4; i++)
         {
             const auto& part = hdr.partitions[i];

kernel/src/fs/Mount.cpp

@@ -6,18 +6,14 @@ Result<SharedPtr<VFS::Inode>> MountInode::create(SharedPtr<VFS::Inode> source, S
 {
     auto inode = TRY(adopt_shared_if_nonnull(new (std::nothrow) MountInode()));
 
+    inode->m_source = source;
     inode->m_mountee = fs;
     inode->m_mount_root_inode = fs->root_inode();
 
-    if (source)
-    {
-        inode->m_source = source;
-
     auto parent = TRY(source->find(".."));
     TRY(fs->set_mount_dir(parent));
 
     source->add_handle();
-    }
 
     g_mounts.append(inode.ptr());
 
@@ -26,5 +22,5 @@ Result<SharedPtr<VFS::Inode>> MountInode::create(SharedPtr<VFS::Inode> source, S
 
 MountInode::~MountInode()
 {
-    if (m_source) m_source->remove_handle();
+    m_source->remove_handle();
 }

kernel/src/fs/Mount.h

@@ -142,27 +142,10 @@ class MountInode : public VFS::Inode, public LinkedListNode<MountInode>
         return m_mount_root_inode->replace_entry(inode, name);
     }
 
-    Result<void> set_source(SharedPtr<VFS::Inode> source)
-    {
-        if (m_source) m_source->remove_handle();
-
-        m_source = source;
-
-        if (source)
-        {
-            auto parent = TRY(source->find(".."));
-            TRY(m_mountee->set_mount_dir(parent));
-
-            source->add_handle();
-        }
-
-        return {};
-    }
-
     virtual ~MountInode();
 
   private:
-    SharedPtr<VFS::Inode> m_source {};
+    SharedPtr<VFS::Inode> m_source;
     SharedPtr<VFS::FileSystem> m_mountee;
     SharedPtr<VFS::Inode> m_mount_root_inode;
 

kernel/src/fs/VFS.cpp

@@ -8,11 +8,11 @@
 
 namespace VFS
 {
-    SharedPtr<VFS::Inode> g_root_inode = {};
+    SharedPtr<FileSystem> root_fs;
 
     Inode& root_inode()
     {
-        return *g_root_inode;
+        return *root_fs->root_inode();
     }
 
     static constexpr int MAX_SYMLINKS = 8;
@@ -40,7 +40,7 @@ namespace VFS
 
                 SharedPtr<VFS::Inode> symlink_root;
 
-                if (PathParser::is_absolute(link.chars())) symlink_root = g_root_inode;
+                if (PathParser::is_absolute(link.chars())) symlink_root = root_fs->root_inode();
                 else
                     symlink_root = parent_inode;
 
@@ -60,7 +60,7 @@ namespace VFS
     {
         SharedPtr<Inode> current_inode;
 
-        if (PathParser::is_absolute(path) || !working_directory) current_inode = g_root_inode;
+        if (PathParser::is_absolute(path) || !working_directory) current_inode = root_fs->root_inode();
         else
             current_inode = working_directory;
 
@@ -180,47 +180,7 @@ namespace VFS
 
     Result<void> mount_root(SharedPtr<VFS::FileSystem> fs)
     {
-        check(!g_root_inode);
+        root_fs = fs;
-
-        g_root_inode = TRY(MountInode::create({}, fs));
-
-        return {};
-    }
-
-    Result<void> pivot_root(const char* new_root, const char* put_old, SharedPtr<VFS::Inode> working_directory)
-    {
-        auto root_parser = TRY(PathParser::create(new_root));
-        auto new_root_parent = TRY(root_parser.dirname());
-        auto new_root_path = TRY(root_parser.basename());
-
-        auto new_root_parent_inode = TRY(VFS::resolve_path(new_root_parent.chars(), Credentials {}, working_directory));
-        auto new_root_inode = TRY(new_root_parent_inode->find(new_root_path.chars()));
-
-        if (new_root_inode->type() != VFS::InodeType::Directory) return err(ENOTDIR);
-        if (!new_root_inode->is_mountpoint()) return err(EINVAL);
-        if (new_root_inode->fs() == g_root_inode->fs()) return err(EBUSY);
-
-        auto parser = TRY(PathParser::create(put_old));
-        auto parent_path = TRY(parser.dirname());
-        auto child = TRY(parser.basename());
-
-        kdbgln("vfs: Pivoting root from / to %s, using %s as new root", put_old, new_root);
-
-        auto parent_inode = TRY(resolve_path(parent_path.chars(), Credentials {}, working_directory));
-
-        auto inode = TRY(parent_inode->find(child.chars()));
-        if (inode->type() != VFS::InodeType::Directory) return err(ENOTDIR);
-        if (inode->is_mountpoint()) return err(EBUSY);
-        if (inode->fs() != new_root_inode->fs()) return err(EINVAL);
-
-        auto mount = g_root_inode;
-
-        TRY(parent_inode->replace_entry(mount, child.chars()));
-        ((MountInode*)mount.ptr())->set_source(inode);
-
-        g_root_inode = new_root_inode;
-        TRY(new_root_parent_inode->replace_entry(((MountInode*)g_root_inode.ptr())->source(), new_root_path.chars()));
-        ((MountInode*)g_root_inode.ptr())->set_source({});
 
         return {};
     }
@@ -253,8 +213,6 @@ namespace VFS
         auto parent_path = TRY(parser.dirname());
         auto child = TRY(parser.basename());
 
-        if (child.view() == "/") return err(EBUSY);
-
         kdbgln("vfs: Unmounting filesystem on target %s", path);
 
         auto parent_inode = TRY(resolve_path(parent_path.chars(), auth, working_directory));

kernel/src/fs/VFS.h

@@ -297,7 +297,6 @@ namespace VFS
     Inode& root_inode();
 
     Result<void> mount_root(SharedPtr<VFS::FileSystem> fs);
-    Result<void> pivot_root(const char* new_root, const char* put_old, SharedPtr<VFS::Inode> working_directory);
     Result<void> mount(const char* path, SharedPtr<VFS::FileSystem> fs, Credentials auth,
                        SharedPtr<Inode> working_directory = {});
 

kernel/src/sys/file.cpp

@@ -16,8 +16,6 @@ Result<u64> sys_read(Registers*, SyscallArgs args)
     u8* buf = (u8*)args[1];
     usize size = (usize)args[2];
 
-    if (!size) return 0;
-
     if (!MemoryManager::validate_user_write(buf, size)) return err(EFAULT);
 
     Thread* current = Scheduler::current();
@@ -46,8 +44,6 @@ Result<u64> sys_write(Registers*, SyscallArgs args)
     const u8* buf = (const u8*)args[1];
     usize size = (usize)args[2];
 
-    if (!size) return 0;
-
     if (!MemoryManager::validate_user_read(buf, size)) return err(EFAULT);
 
     Thread* current = Scheduler::current();

kernel/src/sys/mount.cpp

@@ -36,16 +36,3 @@ Result<u64> sys_umount(Registers*, SyscallArgs args)
 
     return 0;
 }
-
-Result<u64> sys_pivot_root(Registers*, SyscallArgs args)
-{
-    auto new_root = TRY(MemoryManager::strdup_from_user(args[0]));
-    auto put_old = TRY(MemoryManager::strdup_from_user(args[1]));
-
-    auto* current = Scheduler::current();
-    if (current->auth.euid != 0) return err(EPERM);
-
-    TRY(VFS::pivot_root(new_root.chars(), put_old.chars(), current->current_directory));
-
-    return 0;
-}

libluna/CMakeLists.txt

@@ -4,7 +4,6 @@ file(GLOB HEADERS include/luna/*.h)
 
 set(FREESTANDING_SOURCES
     ${HEADERS}
-    src/CRC32.cpp
     src/Format.cpp
     src/Sort.cpp
     src/NumberParsing.cpp

libluna/include/luna/CRC32.h

@@ -1,7 +0,0 @@
-#pragma once
-#include <luna/Types.h>
-
-namespace CRC32
-{
-    u32 checksum(const u8* data, usize size);
-}

libluna/include/luna/Syscall.h

@@ -5,8 +5,7 @@
         _e(lseek) _e(mkdir) _e(execve) _e(fork) _e(waitpid) _e(getppid) _e(fcntl) _e(getdents) _e(getuid) _e(geteuid)  \
             _e(getgid) _e(getegid) _e(setuid) _e(setgid) _e(seteuid) _e(setegid) _e(fchmodat) _e(fchownat) _e(ioctl)   \
                 _e(fstatat) _e(chdir) _e(getcwd) _e(unlinkat) _e(uname) _e(sethostname) _e(dup2) _e(pipe) _e(mount)    \
-                    _e(umount) _e(pstat) _e(getrusage) _e(symlinkat) _e(readlinkat) _e(umask) _e(linkat) _e(faccessat) \
+                    _e(umount) _e(pstat) _e(getrusage) _e(symlinkat) _e(readlinkat) _e(umask) _e(linkat) _e(faccessat)
-                        _e(pivot_root)
 
 enum Syscalls
 {

libluna/include/luna/Types.h

@@ -1,4 +1,3 @@
-#pragma once
 #include <stddef.h>
 #include <stdint.h>
 

libluna/src/CRC32.cpp

@@ -1,52 +0,0 @@
-#include <luna/CRC32.h>
-#include <luna/DebugLog.h>
-
-static const u32 crc_table[] = {
-    0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832,
-    0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
-    0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856, 0x646ba8c0, 0xfd62f97a,
-    0x8a65c9ec, 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
-    0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3,
-    0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
-    0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, 0x2f6f7c87, 0x58684c11, 0xc1611dab,
-    0xb6662d3d, 0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
-    0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01, 0x6b6b51f4,
-    0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
-    0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074,
-    0xd4bb30e2, 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
-    0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, 0x5768b525,
-    0x206f85b3, 0xb966d409, 0xce61e49f, 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
-    0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615,
-    0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
-    0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7, 0xfed41b76,
-    0x89d32be0, 0x10da7a5a, 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
-    0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c, 0x36034af6,
-    0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
-    0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7,
-    0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
-    0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7,
-    0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
-    0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278,
-    0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
-    0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9, 0xbdbdf21c, 0xcabac28a, 0x53b39330,
-    0x24b4a3a6, 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
-    0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
-};
-
-namespace CRC32
-{
-    // FIXME: This shouldn't return 0xffffffff when there are 4 zeros in a row somewhere in the data, right? That's what
-    // happens to the GPT header. (other CRC32 implementations don't seem to have this problem)
-    u32 checksum(const u8* data, usize size)
-    {
-        u32 crc = 0xffffffffu;
-
-        for (usize i = 0; i < size; i++)
-        {
-            const u32 index = (crc & data[i]) & 0xff;
-            crc = (crc >> 8) ^ (crc_table[index]);
-        }
-
-        return ~crc;
-    }
-}