vfs interface

boot/limine/entry.c

@@ -2,8 +2,8 @@
 #include <zinnia/cmdline.h>
 #include <zinnia/init.h>
 #include <zinnia/print.h>
-#include <zinnia/utils.h>
 #include <zinnia/string.h>
+#include <zinnia/utils.h>
 #include "limine.h"
 
 [[__initdata_sorted("limine.0")]]

core/clock.c

@@ -48,6 +48,7 @@ bool clock_switch(struct clock* clock) {
     spin_unlock(&lock);
 
     log("clock: Switching to clock source \"%s\"\n", clock->name);
+
     return true;
 }
 

core/dpc.c

@@ -0,0 +1,3 @@
+#include <zinnia/dpc.h>
+
+// TODO

core/lib/runtime.c

@@ -1,5 +1,4 @@
-// Compiler runtime support like libgcc or compiler-rt.
-// Extend as required.
+// Compiler runtime support.
 
 #include <stdint.h>
 

core/mem/pmap.c

@@ -2,9 +2,9 @@
 #include <zinnia/errno.h>
 #include <zinnia/pmap.h>
 #include <zinnia/spin.h>
+#include <zinnia/string.h>
 #include <zinnia/vma.h>
 #include <config.h>
-#include <zinnia/string.h>
 
 // TODO: For now, we assume that we can do generic PTE lookups on every arch that has a MMU.
 static_assert(CONFIG_HAVE_MMU_GENERIC);

core/mem/pmm.c

@@ -3,9 +3,9 @@
 #include <zinnia/panic.h>
 #include <zinnia/print.h>
 #include <zinnia/spin.h>
+#include <zinnia/string.h>
 #include <zinnia/virt.h>
 #include <stdint.h>
-#include <zinnia/string.h>
 
 uintptr_t mem_hhdm_base = 0;
 

core/mem/vma.c

@@ -60,7 +60,7 @@ static struct vma_mapping* find_mapping(struct vma* v, size_t page) {
     return nullptr;
 }
 
-static bool access_allowed(enum prot_flags prot, const struct vma_fault_info* info) {
+static bool can_access(enum prot_flags prot, const struct vma_fault_info* info) {
     if (info->caused_by_write)
         return prot & PROT_WRITE;
     if (info->caused_by_fetch)
@@ -87,7 +87,7 @@ bool vma_page_fault(struct vma* v, const struct vma_fault_info* info) {
 
     spin_lock(&v->lock);
     struct vma_mapping* mapping = find_mapping(v, faulty_page);
-    if (!mapping || !access_allowed(mapping->prot, info)) {
+    if (!mapping || !can_access(mapping->prot, info)) {
         spin_unlock(&v->lock);
         return false;
     }
@@ -107,8 +107,7 @@ bool vma_page_fault(struct vma* v, const struct vma_fault_info* info) {
     spin_lock(&v->lock);
     mapping = find_mapping(v, faulty_page);
     const bool still_valid = mapping && mapping->object == object &&
-        (faulty_page - mapping->start_page) + mapping->offset_page == object_page &&
-        access_allowed(mapping->prot, info);
+        (faulty_page - mapping->start_page) + mapping->offset_page == object_page && can_access(mapping->prot, info);
 
     if (still_valid) {
         errno_t status =

core/mem/vmo.c

@@ -1,9 +1,9 @@
 #include <zinnia/alloc.h>
 #include <zinnia/errno.h>
 #include <zinnia/list.h>
+#include <zinnia/string.h>
 #include <zinnia/utils.h>
 #include <zinnia/vmo.h>
-#include <zinnia/string.h>
 
 void vmo_ref(struct vmo* obj) {
     refcount_inc(&obj->rc);
@@ -211,6 +211,25 @@ errno_t vmo_new_phys(struct paged_vmo** out) {
     return vmo_new_paged(phys_pager, out);
 }
 
+void vmo_truncate_paged(struct paged_vmo* paged, size_t length) {
+    const size_t page_size = arch_mem_page_size();
+    const size_t keep_pages = ROUND_UP(length, page_size) / page_size;
+
+    spin_lock(&paged->lock);
+    struct page_list** pp = &list_first(&paged->cache);
+    while (*pp) {
+        struct page_list* entry = *pp;
+        if (entry->offset >= keep_pages) {
+            *pp = list_next(entry, next);
+            paged->source.put_page(&paged->source, entry->offset, entry->value);
+            mem_free(entry);
+        } else {
+            pp = &list_next(entry, next);
+        }
+    }
+    spin_unlock(&paged->lock);
+}
+
 struct phys_range_vmo {
     struct vmo object;
     uintptr_t start;

core/meson.build

@@ -1,7 +1,6 @@
 kernel_sources += files(
     'clock.c',
     'console.c',
-    'elf.c',
     'irq.c',
     'module.c',
     'panic.c',

core/percpu.c

@@ -29,6 +29,9 @@ struct percpu* percpu_new() {
     const size_t size = __ld_percpu_end - __ld_percpu_start;
     const size_t num_pages = ALIGN_UP(size, arch_mem_page_size()) / arch_mem_page_size();
 
+    // TODO: Map pages past the end of the kernel.
+    // TODO: Document how allocations work.
+
     phys_t mem;
     if (mem_phys_alloc(num_pages, 0, &mem))
         return nullptr;

core/spin.c

@@ -1,6 +1,11 @@
 #include <zinnia/spin.h>
 #include <stdatomic.h>
 
+void spin_init(struct spinlock* spin) {
+    spin->next = 0;
+    spin->owner = 0;
+}
+
 void spin_lock(struct spinlock* spin) {
     uint32_t my = atomic_fetch_add_explicit(&spin->next, 1, memory_order_relaxed);
 

dev/meson.build

@@ -1,12 +1,9 @@
 subdir('common')
 subdir('block')
+subdir('dt')
 
 if kconfig.get('CONFIG_ACPI', 'n') == 'y'
     subdir('acpi')
 endif
 
-if kconfig.get('CONFIG_DT', 'n') == 'y'
-    subdir('dt')
-endif
-
 module_lds = meson.current_source_dir() / 'module.ld'

fs/exec/elf.c

@@ -9,6 +9,7 @@
 #include <zinnia/sched.h>
 #include <zinnia/string.h>
 #include <zinnia/utils.h>
+#include <zinnia/vfs.h>
 #include <zinnia/vma.h>
 #include <zinnia/vmo.h>
 #include <bits/elf.h>

fs/exec/meson.build

@@ -0,0 +1,3 @@
+kernel_sources += files(
+    'elf.c',
+)

fs/meson.build

@@ -1 +1 @@
-subdir('tmpfs')
+subdir('exec')

fs/tmpfs/meson.build

@@ -1 +0,0 @@
-kernel_sources += files('tmpfs.c')

fs/tmpfs/tmpfs.c

@@ -1 +0,0 @@
-// TODO

fs/vfs/ident.c

@@ -0,0 +1,7 @@
+#include <zinnia/ident.h>
+
+static const struct ident kernel_identity = {0};
+
+const struct ident* ident_kernel() {
+    return &kernel_identity;
+}

fs/vfs/meson.build

@@ -0,0 +1,3 @@
+kernel_sources += files(
+    'ident.c',
+)

include/uapi/time.h

@@ -17,12 +17,12 @@ struct __timeval {
     __suseconds_t tv_usec;
 };
 
-struct itimerval {
+struct __itimerval {
     struct __timeval it_interval;
     struct __timeval it_value;
 };
 
-struct itimerspec {
+struct __itimerspec {
     struct __timespec it_interval;
     struct __timespec it_value;
 };

include/zinnia/alloc.h

@@ -26,7 +26,10 @@ struct phys_mem {
 
 // Base address of the HHDM.
 extern uintptr_t mem_hhdm_base;
-#define HHDM_PTR(paddr) (void*)(mem_hhdm_base + (paddr))
+
+static inline void* HHDM_PTR(phys_t paddr) {
+    return (void*)(mem_hhdm_base + paddr);
+}
 
 // Allocates a region of memory which can be smaller than the page size.
 // Returns `nullptr` if the allocator cannot provide an allocation for the given `length` + `flags`.

include/zinnia/dpc.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#include <zinnia/list.h>
+#include <zinnia/percpu.h>
+#include <stdatomic.h>
+
+struct dpc {
+    void (*const callback)(struct dpc* dpc, void* data);
+    void* data;
+    atomic_bool inserted;
+
+    list_link(struct dpc*) link;
+};
+
+void dpc_dispatch();
+
+struct dpc_percpu {};
+extern struct dpc_percpu dpc_percpu_data;

include/zinnia/elf.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <zinnia/errno.h>
+#include <zinnia/vfs.h>
 #include <bits/elf.h>
 #include <stdint.h>
 
@@ -341,15 +342,4 @@ static inline uint32_t ELF64_R_TYPE(uint64_t info) {
     return info & 0xFFFFFFFF;
 }
 
-struct vma;
-struct vmo;
-struct task;
-
-struct exec_info {
-    struct vma* space;
-    struct vmo* file_obj;
-    const char** argv;
-    const char** envp;
-};
-
 errno_t elf_load(struct exec_info* info, struct task** out);

include/zinnia/fdt.h

@@ -0,0 +1,45 @@
+#pragma once
+
+#include <stddef.h>
+#include <stdint.h>
+
+struct fdt_header {
+    uint32_t magic;
+    uint32_t total_size;
+    uint32_t structs_offset;
+    uint32_t strings_offset;
+    uint32_t reserved_offset;
+    uint32_t version;
+    uint32_t compat_version;
+    uint32_t boot_cpuid;
+    uint32_t strings_size;
+    uint32_t structs_size;
+};
+
+constexpr uint32_t FDT_BEGIN_NODE = 0x00000001;
+constexpr uint32_t FDT_END_NODE = 0x00000002;
+constexpr uint32_t FDT_PROP = 0x00000003;
+constexpr uint32_t FDT_NOP = 0x00000004;
+constexpr uint32_t FDT_END = 0x00000009;
+
+struct fdt {
+    uint32_t version;
+    uint32_t compat_version;
+    uint32_t boot_cpuid;
+
+    const uint8_t* structs;
+    size_t structs_len;
+    const uint8_t* strings;
+    size_t strings_len;
+};
+
+struct fdt_node {
+    struct fdt* tree;
+};
+
+struct fdt_prop {
+    struct fdt* tree;
+};
+
+// Root of the device tree.
+struct fdt_node fdt_root(struct fdt* tree);

include/zinnia/ident.h

@@ -1,5 +1,13 @@
 #pragma once
 
+#include <zinnia/types.h>
+#include <zinnia/vec.h>
+
 struct ident {
-    // TODO
+    uid_t uid, euid, suid;
+    gid_t gid, egid, sgid;
+
+    vec(gid_t) groups;
 };
+
+const struct ident* ident_kernel(void);

include/zinnia/iovec.h

@@ -1,12 +1,37 @@
 #pragma once
 
+#include <zinnia/errno.h>
+#include <zinnia/string.h>
+#include <zinnia/usercopy.h>
+#include <zinnia/utils.h>
+#include <stddef.h>
 #include <uapi/uio.h>
 
 struct iovec_iter {
-    struct iovec* iovecs;
+    struct __iovec* iovecs;
     size_t iovecs_len;
     size_t total_len;
     size_t total_offset;
     size_t current_idx;
     size_t current_offset;
 };
+
+static inline size_t iovec_iter_len(struct iovec_iter* iter) {
+    return iter->total_len - iter->total_offset;
+}
+
+// Creates an iovec iterator over kernel memory.
+static inline struct iovec_iter iovec_iter_kernel(struct __iovec* iovecs, size_t count) {
+    size_t total = 0;
+    for (size_t i = 0; i < count; i++)
+        total += iovecs[i].len;
+
+    return (struct iovec_iter){
+        .iovecs = iovecs,
+        .iovecs_len = count,
+        .total_len = total,
+        .total_offset = 0,
+        .current_idx = 0,
+        .current_offset = 0,
+    };
+}

include/zinnia/spin.h

@@ -10,6 +10,8 @@ struct spinlock {
     _Atomic(uint32_t) next;
 };
 
+void spin_init(struct spinlock* spin);
+
 // Attempts to lock a spinlock. If it's already locked, waits until it's freed.
 void spin_lock(struct spinlock* spin);
 

include/zinnia/time.h

@@ -2,6 +2,16 @@
 
 #include <uapi/time.h>
 
-struct timespec time_from_sec(uint64_t sec);
-struct timespec time_from_nano(uint64_t nsec);
-struct timespec time_from_milli(uint64_t msec);
+typedef struct __timespec timespec_t;
+
+static inline timespec_t time_from_sec(uint64_t sec) {
+    return (timespec_t){.tv_sec = sec, .tv_nsec = 0};
+}
+
+static inline timespec_t time_from_nano(uint64_t nsec) {
+    return (timespec_t){.tv_sec = nsec / 1'000'000'000, .tv_nsec = nsec % 1'000'000'000};
+}
+
+static inline timespec_t time_from_milli(uint64_t msec) {
+    return (timespec_t){.tv_sec = msec / 1'000, .tv_nsec = (msec % 1'000) * 1'000'000};
+}

include/zinnia/vfs.h

@@ -3,13 +3,35 @@
 #include <zinnia/errno.h>
 #include <zinnia/ident.h>
 #include <zinnia/iovec.h>
+#include <zinnia/mman.h>
+#include <zinnia/mutex.h>
 #include <zinnia/refcount.h>
 #include <zinnia/spin.h>
+#include <zinnia/tailq.h>
+#include <zinnia/time.h>
 #include <zinnia/types.h>
+#include <zinnia/vec.h>
+#include <zinnia/vma.h>
+#include <zinnia/vmo.h>
 #include <stddef.h>
 #include <stdint.h>
+#include <uapi/dirent.h>
 #include <uapi/fcntl.h>
+#include <uapi/limits.h>
+#include <uapi/mount.h>
 #include <uapi/stat.h>
+#include <uapi/statvfs.h>
+#include <uapi/time.h>
+
+struct vfs_mount;
+struct vfs_entry;
+struct vfs_path;
+struct vfs_node;
+struct vfs_file;
+struct vfs_super_block;
+struct vfs_filesystem;
+struct vfs_node_ops;
+struct vfs_file_ops;
 
 enum open_flags : uint32_t {
     O_RDONLY = __O_RDONLY,
@@ -38,24 +60,30 @@ enum open_flags : uint32_t {
     O_ACCMODE = __O_ACCMODE,
 };
 
-struct vfs_mount {
-    struct refcount rc;
-    // TODO
+enum mount_flags : uint32_t {
+    MNT_RDONLY = __MNT_RDONLY,
+    MNT_NOSUID = __MNT_NOSUID,
+    MNT_NOEXEC = __MNT_NOEXEC,
+    MNT_RELATIME = __MNT_RELATIME,
+    MNT_NOATIME = __MNT_NOATIME,
+    MNT_REMOUNT = __MNT_REMOUNT,
+    MNT_FORCE = __MNT_FORCE,
 };
 
-struct vfs_entry {
-    struct refcount rc;
-    // TODO
+struct exec_info {
+    struct vma* space;
+    struct vmo* file_obj;
+    const char** argv;
+    const char** envp;
 };
 
-struct vfs_path {
-    struct vfs_mount* mount;
-    struct vfs_entry* entry;
+enum vfs_lookup_flags : uint32_t {
+    VFS_LOOKUP_FOLLOW_SYMLINKS = 1 << 0,
+    VFS_LOOKUP_MUST_EXIST = 1 << 1,
+    VFS_LOOKUP_MUST_NOT_EXIST = 1 << 2,
+    VFS_LOOKUP_REAL_ID = 1 << 3,
 };
 
-errno_t vfs_path_mount();
-errno_t vfs_path_lookup(struct vfs_path);
-
 enum vfs_node_type {
     VNODE_REGULAR,
     VNODE_DIRECTORY,
@@ -64,56 +92,373 @@ enum vfs_node_type {
     VNODE_BLOCKDEV,
     VNODE_CHARDEV,
     VNODE_SOCKET,
+    VNODE_ANONYMOUS,
+};
+
+enum vfs_entry_state {
+    VFS_ENTRY_NOT_CACHED,  // Entry hasn't been looked up yet.
+    VFS_ENTRY_PRESENT,     // Entry is positive and contains a link to the inode.
+    VFS_ENTRY_NOT_PRESENT, // Entry is negative.
+};
+
+struct vfs_entry {
+    struct refcount rc;
+    // The name of this entry.
+    char* name;
+    size_t name_len;
+    struct mutex lock;
+
+    enum vfs_entry_state state;
+    // The inode this entry points to when present.
+    struct vfs_node* inode;
+    // The parent of this entry, weak reference.
+    struct vfs_entry* parent;
+
+    // All cached children of this entry.
+    tailq_head(struct vfs_entry) children;
+    tailq_link(struct vfs_entry) child_link;
+
+    // A list of mounts on this entry.
+    vec(struct vfs_mount*) mounts;
+};
+
+struct vfs_path {
+    struct vfs_mount* mount;
+    struct vfs_entry* entry;
+};
+
+struct vfs_path vfs_path_clone(struct vfs_path path);
+void vfs_path_drop(struct vfs_path path);
+
+struct vfs_mount {
+    struct refcount rc;
+    enum mount_flags flags;
+    struct vfs_entry* root;
+    struct vfs_path mount_point;
+    bool has_mount_point;
+};
+
+void vfs_mount_ref(struct vfs_mount* mount);
+void vfs_mount_unref(struct vfs_mount* mount);
+errno_t vfs_mount(const char* fs_name, enum mount_flags flags, void* arg, struct vfs_mount** out);
+errno_t vfs_unmount(struct vfs_mount* mount);
+
+struct vfs_super_block_ops {
+    errno_t (*sync)(struct vfs_super_block* sb);
+    errno_t (*statvfs)(struct vfs_super_block* sb, struct __statvfs* out);
+    void (*destroy)(struct vfs_super_block* sb);
+};
+
+struct vfs_super_block {
+    struct refcount rc;
+    const struct vfs_super_block_ops* ops;
+};
+
+// TODO: Maybe not like this
+struct vfs_mknod_target {
+    enum vfs_node_type type;
+    const struct vfs_node_ops* ops;
+    void* priv;
 };
 
-struct vfs_file;
-struct vfs_node;
 struct vfs_node_ops {
-    errno_t (*sync)();
+    // Synchronizes the node metadata back to the underlying file system.
+    errno_t (*sync)(struct vfs_node* node);
+    // Destroys private state and drops references.
+    void (*destroy)(struct vfs_node* node);
+    // Operations that can be performed on an open file of this node.
+    const struct vfs_file_ops* file_ops;
+
     union {
+        // VNODE_REGULAR
         struct {
-            errno_t (*truncate)(struct vfs_node*, uint64_t new_length);
+            // Truncates the file down to `new_length` bytes.
+            errno_t (*truncate)(struct vfs_node* node, uint64_t new_length);
         } regular;
+
+        // VNODE_SYMLINK
         struct {
-            errno_t (*read_link)(struct vfs_node*, char* buf, size_t len, size_t* out_written);
+            // Reads the value of the symlink into `buf`.
+            errno_t (*read_link)(struct vfs_node* node, struct iovec_iter* iter, size_t* out_read);
         } symlink;
+
+        // VNODE_DIR
         struct {
-            errno_t (*lookup)(struct vfs_node*, struct vfs_path entry);
+            errno_t (*lookup)(struct vfs_node* node, struct vfs_path* child);
             errno_t (*open)(
-                struct vfs_node*,
-                struct vfs_path entry,
+                struct vfs_node* node,
+                struct vfs_path* path,
                 enum open_flags flags,
                 const struct ident* identity,
-                struct vfs_file* out_file
+                struct vfs_file** out_file
+            );
+            errno_t (*create)(
+                struct vfs_node* node,
+                struct vfs_entry* entry,
+                mode_t mode,
+                const struct ident* identity
+            );
+            errno_t (*mkdir)(struct vfs_node* node, struct vfs_path* path, mode_t mode, const struct ident* identity);
+            errno_t (*symlink)(
+                struct vfs_node* node,
+                struct vfs_path* path,
+                const char* target,
+                size_t target_len,
+                const struct ident* identity
+            );
+            errno_t (*link)(
+                struct vfs_node* node,
+                struct vfs_path* path,
+                struct vfs_node* target,
+                const struct ident* identity
+            );
+            errno_t (*unlink)(struct vfs_node* node, struct vfs_path* path, const struct ident* identity);
+            errno_t (*rmdir)(struct vfs_node* node, struct vfs_path* path, const struct ident* identity);
+            errno_t (*rename)(
+                struct vfs_node* node,
+                struct vfs_path* path,
+                struct vfs_node* target,
+                struct vfs_path* target_path,
+                const struct ident* identity
+            );
+            errno_t (*mknod)(
+                struct vfs_node* node,
+                mode_t mode,
+                struct vfs_mknod_target* target,
+                const struct ident* identity,
+                struct vfs_node** out
+            );
+            errno_t (*get_dir_entries)(
+                struct vfs_node* node,
+                struct vfs_entry* entry,
+                off_t offset,
+                struct __dirent* buffer,
+                size_t buffer_len,
+                const struct ident* identity,
+                size_t* out_count
             );
-            errno_t (*create)(struct vfs_node*, const struct ident* identity);
         } dir;
     };
 };
 
 struct vfs_node {
+    struct refcount rc;
     enum vfs_node_type type;
     bool is_seekable;
+
+    const struct vfs_node_ops* ops;
+    const struct vfs_file_ops* file_ops;
+    struct vfs_super_block* sb;
+
+    struct mutex lock;
+    void* priv;
+
+    ino_t id;
+    size_t size;
+    mode_t mode;
+    uid_t uid;
+    gid_t gid;
+    timespec_t atime;
+    timespec_t mtime;
+    timespec_t ctime;
 };
 
-struct vfs_file;
 struct vfs_file_ops {
     errno_t (*read)(struct vfs_file* file, struct iovec_iter* buffer, uint64_t offset, ssize_t* out_read);
     errno_t (*write)(struct vfs_file* file, struct iovec_iter* buffer, uint64_t offset, ssize_t* out_written);
     errno_t (*ioctl)(struct vfs_file* file, uintptr_t request, uintptr_t arg, uintptr_t* out_result);
+    errno_t (*sync)(struct vfs_file* file, bool data_only);
+    errno_t (*mmap)(
+        struct vfs_file* file,
+        struct vma* vma,
+        uintptr_t addr,
+        size_t len,
+        enum prot_flags prot,
+        enum map_flags flags,
+        off_t offset,
+        uintptr_t* out_addr
+    );
+    bool (*seekable)(struct vfs_file* file);
 };
 
+enum vfs_file_position {
+    VFS_POSITION_STREAM,   // The file has no meaningful position.
+    VFS_POSITION_POSITION, // The file has a position, but accesses do not serialize the whole operation.
+    VFS_POSITION_ATOMIC,   // Accesses through the shared file position are serialized.
+};
+
+enum vfs_seek_anchor {
+    VFS_SEEK_START,
+    VFS_SEEK_CURRENT,
+    VFS_SEEK_END,
+};
+
+// The kernel representation of an open file.
 struct vfs_file {
     struct refcount rc;
-    const struct vfs_file_ops* ops; // vtable for operations on this open file.
-    struct vfs_node* vnode;         // The opened vnode.
-    const char* abs_path;           // Absolute path resolved during `open()`.
-    struct spinlock lock;
+    const struct vfs_file_ops* ops;
+    struct vfs_node* vnode;
 
-    struct vfs_path path; // The cached entry pointing to this node.
-    bool has_path;        // If this file has a path.
+    // Absolute path resolved during open.
+    char* absolute_path;
+    enum open_flags flags;
+
+    enum vfs_file_position position_kind;
+    off_t position;
+    struct mutex lock;
+
+    struct vfs_path path;
+    bool has_path;
 };
 
-errno_t vfs_file_read(struct vfs_file* file, struct iovec_iter* buffer, uint64_t offset, ssize_t* out_read);
-errno_t vfs_file_write(struct vfs_file* file, struct iovec_iter* buffer, uint64_t offset, ssize_t* out_written);
+// A file system driver.
+struct vfs_filesystem {
+    const char* name;
+    errno_t (*mount)(const struct vfs_filesystem* fs, enum mount_flags flags, void* arg, struct vfs_mount** out);
+};
+
+void vfs_node_ref(struct vfs_node* node);
+void vfs_node_unref(struct vfs_node* node);
+void vfs_entry_ref(struct vfs_entry* entry);
+void vfs_entry_unref(struct vfs_entry* entry);
+void vfs_file_ref(struct vfs_file* file);
+void vfs_file_unref(struct vfs_file* file);
+void vfs_super_block_ref(struct vfs_super_block* sb);
+void vfs_super_block_unref(struct vfs_super_block* sb);
+
+// Gets the kernel path representation of the absolute root.
+struct vfs_path vfs_get_root();
+
+void vfs_init();
+
+errno_t vfs_register_filesystem(const struct vfs_filesystem* fs);
+
+errno_t vfs_sync_all();
+
+// Resolves a `path` to a VFS path, relative to `root` and `cwd`.
+// Returns the result in `out` if the lookup with the given flags was successful.
+errno_t vfs_path_lookup(
+    struct vfs_path root,
+    struct vfs_path cwd,
+    const char* path,
+    const struct ident* identity,
+    enum vfs_lookup_flags flags,
+    struct vfs_path* out
+);
+
+errno_t vfs_path_lookup_parent(struct vfs_path path, struct vfs_path* out);
+
+errno_t vfs_path_lookup_child(
+    struct vfs_path path,
+    struct vfs_path* root,
+    const char* name,
+    size_t name_len,
+    struct vfs_path* out
+);
+
+// Builds the absolute path of `path` from `root` and stores the result in `buf`.
+// Returns the amount of actually written bytes in `out_len`.
+errno_t vfs_path_absolute(struct vfs_path path, struct vfs_path* root, char* buf, size_t len, size_t* out_len);
+
+// Creates a new directory at `path`, relative to `root` and `cwd` with `mode`.
+errno_t vfs_mkdir(
+    struct vfs_path root,
+    struct vfs_path cwd,
+    const char* path,
+    mode_t mode,
+    const struct ident* identity
+);
+
+// Creates a new symbolic link at `path`, relative to `root` and `cwd`, pointing to `target`.
+errno_t vfs_symlink(
+    struct vfs_path root,
+    struct vfs_path cwd,
+    const char* path,
+    const char* target,
+    const struct ident* identity
+);
+
+// Unlinks a file at `path`, relative to `root` and `cwd`.
+errno_t vfs_unlink(struct vfs_path root, struct vfs_path cwd, const char* path, const struct ident* identity);
+
+// Removes a directory at `path`, relative to `root` and `cwd`.
+errno_t vfs_rmdir(struct vfs_path root, struct vfs_path cwd, const char* path, const struct ident* identity);
+
+errno_t vfs_mknod(
+    struct vfs_path root,
+    struct vfs_path cwd,
+    const char* path,
+    mode_t mode,
+    struct vfs_mknod_target* target,
+    const struct ident* identity
+);
+
+// Checks if an access to a `node` with `flags` using `identity` is allowed.
+// Returns 0 if the access is allowed.
+errno_t vfs_node_try_access(struct vfs_node* node, const struct ident* identity, enum open_flags flags, bool use_real);
+
+// Opens a node at `path`, relative to `root` and `cwd`.
+// Returns the opened node as a file in `out`.
+errno_t vfs_file_open(
+    struct vfs_path root,
+    struct vfs_path cwd,
+    const char* path,
+    enum open_flags flags,
+    mode_t mode,
+    const struct ident* identity,
+    struct vfs_file** out
+);
+
+// Reads from a `file` into a `buffer` from the current offset.
+// Returns the actual bytes read in `out_read`.
+errno_t vfs_file_read(struct vfs_file* file, struct iovec_iter* buffer, ssize_t* out_read);
+
+// Same as `vfs_file_read`, but from a given offset.
+errno_t vfs_file_pread(struct vfs_file* file, struct iovec_iter* buffer, uint64_t offset, ssize_t* out_read);
+
+// Wites to a `file` from a `buffer` from the current offset.
+// Returns the actual bytes written in `out_written`.
+errno_t vfs_file_write(struct vfs_file* file, struct iovec_iter* buffer, ssize_t* out_written);
+
+// Same as `vfs_file_write`, but from a given offset.
+errno_t vfs_file_pwrite(struct vfs_file* file, struct iovec_iter* buffer, uint64_t offset, ssize_t* out_written);
+
+// Performs a generic `request` on a `file`.
+// Returns the result in `out_result`.
 errno_t vfs_file_ioctl(struct vfs_file* file, uintptr_t request, uintptr_t arg, uintptr_t* out_result);
+
+errno_t vfs_file_sync(struct vfs_file* file, bool data_only);
+
+errno_t vfs_file_seek(struct vfs_file* file, enum vfs_seek_anchor anchor, off_t offset, off_t* out_position);
+off_t vfs_file_tell(struct vfs_file* file);
+
+// Maps `len` bytes of a `file` from `offset` into `vma` at `addr`.
+// Returns the start of the mapped region in `out_addr`.
+errno_t vfs_file_mmap(
+    struct vfs_file* file,
+    struct vma* vma,
+    uintptr_t addr,
+    size_t len,
+    enum prot_flags prot,
+    enum map_flags flags,
+    off_t offset,
+    uintptr_t* out_addr
+);
+
+// Directory listing.
+errno_t vfs_get_dir_entries(
+    struct vfs_file* file,
+    struct __dirent* buffer,
+    size_t buffer_len,
+    const struct ident* identity,
+    size_t* out_count
+);
+
+// Creates an inode belonging to the anonymous pseudo file system.
+errno_t vfs_create_anon_inode(
+    const struct vfs_file_ops* file_ops,
+    enum vfs_node_type type,
+    mode_t mode,
+    const struct ident* identity,
+    struct vfs_node** out
+);

include/zinnia/vmo.h

@@ -33,7 +33,7 @@ struct pager_ops {
     errno_t (*put_page)(struct pager_ops* pager, uintptr_t offset_idx, struct page* page);
 };
 
-// TODO: change to btree
+// TODO: change to rbtree
 struct page_list {
     uintptr_t offset;
     struct page* value;
@@ -50,5 +50,8 @@ struct paged_vmo {
 errno_t vmo_new_paged(struct pager_ops ops, struct paged_vmo** out);
 errno_t vmo_new_phys(struct paged_vmo** out);
 
+// Drops all cached pages past `length` bytes.
+void vmo_truncate_paged(struct paged_vmo* paged, size_t length);
+
 // Creates a VMO backed by a specific physical address range (e.g. for MMIO).
 errno_t vmo_new_phys_range(uintptr_t addr, size_t length, struct vmo** out);

syscalls/uname.c

@@ -13,7 +13,7 @@ static struct __utsname uname_buf = {
     .version = CONFIG_KERNEL_FLAVOR,
     .nodename = "localhost",
     .machine = ZINNIA_ARCH,
-    .domainname = "none",
+    .domainname = "(none)",
 };
 
 struct syscall_ret sys_setuname(const __user struct __utsname* ptr) {