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rewrite file system layer

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This commit is contained in:
Benji Dial 2024-01-12 20:39:21 -05:00
parent c4ab2f6f44
commit 882e74b219
18 changed files with 746 additions and 832 deletions
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6
documentation/storage.txt
View file

@ -2,6 +2,6 @@ a block_device is a block device such as a disk or a partition that has been
seen since the last boot. when a driver detects a device, it should check if seen since the last boot. when a driver detects a device, it should check if
a block_device with that id has already been created, and if so, reuse it. a block_device with that id has already been created, and if so, reuse it.
eventually, i would like to implement kernel-space exceptions and use those eventually, i would like to implement kernel-space exceptions and
instead of having functions return an io_result, since it's a bit unwieldy use those instead of having functions return bd_result or fs_result,
to propogate those results as is. since it's a bit unwieldy to propogate those results as is.

23
include/mercury/kernel/bd/memory.hpp
View file

@ -1,23 +0,0 @@
#ifndef MERCURY_KERNEL_BD_MEMORY_HPP
#define MERCURY_KERNEL_BD_MEMORY_HPP
#include <mercury/kernel/storage.hpp>
namespace mercury::kernel::bd {
class memory : public storage::block_device {
private:
uint8_t *buffer;
public:
memory(void *buffer, size_t buffer_len);
storage::io_result read_blocks_no_cache(uint64_t start, uint64_t count, void *into) override;
storage::io_result write_blocks_no_cache(uint64_t start, uint64_t count, const void *from) override;
};
}
#endif

45
include/mercury/kernel/fs/tarfs.hpp
View file

@ -1,45 +0,0 @@
#ifndef MERCURY_KERNEL_FS_TARFS_HPP
#define MERCURY_KERNEL_FS_TARFS_HPP
#include <mercury/kernel/storage.hpp>
namespace mercury::kernel::fs {
class tarfs_instance : public storage::file_system_instance {
private:
storage::block_device *bd;
storage::io_result next_node(storage::node_id_t &node);
//name_buf must be at least 255 chars long.
storage::io_result read_name(storage::node_id_t node, char *name_buf, unsigned &name_len_out);
//len <= 12
storage::io_result read_num(uint64_t offset, unsigned len, uint64_t &out);
public:
tarfs_instance(storage::block_device *bd);
storage::io_result get_root_node(storage::node_id_t &out) override;
storage::io_result get_first_child(
storage::node_id_t node, storage::node_id_t &out, storage::directory_iter_t &iter_out) override;
storage::io_result get_next_child(
storage::node_id_t node, storage::node_id_t &out, storage::directory_iter_t &iter) override;
storage::io_result get_child(
storage::node_id_t node, storage::node_id_t &out, const char *name, unsigned name_len) override;
storage::io_result get_name_length(storage::node_id_t node, unsigned &length_out) override;
storage::io_result get_name(storage::node_id_t node, char *buffer, unsigned &length_out) override;
storage::io_result get_file_length(storage::node_id_t node, uint64_t &length_out) override;
storage::io_result get_file_type(storage::node_id_t node, storage::file_type &out) override;
storage::io_result resize_file(storage::node_id_t node, uint64_t new_length) override;
storage::io_result read_bytes_from_file(
storage::node_id_t node, uint64_t start, uint64_t count, void *into) override;
storage::io_result write_bytes_into_file(
storage::node_id_t node, uint64_t start, uint64_t count, const void *from) override;
};
storage::io_result tarfs_mounter(storage::block_device *bd, storage::file_system_instance *&fs_out);
}
#endif

107
include/mercury/kernel/storage.hpp
View file

@ -9,22 +9,32 @@ namespace mercury::kernel::storage {
typedef uint64_t node_id_t; typedef uint64_t node_id_t;
typedef uint64_t directory_iter_t; typedef uint64_t directory_iter_t;
enum file_type { enum class file_type {
regular_file, regular_file,
directory, directory,
symlink symlink
}; };
enum io_result { enum class bd_result {
success, success,
mount_point_already_used,
not_a_directory,
not_supported,
out_of_bounds, out_of_bounds,
device_error
};
enum class fs_result {
success,
device_error, device_error,
fs_corrupt, fs_corrupt
not_found, };
bad_path,
struct dir_entry {
utility::string name;
node_id_t node;
file_type type;
//only used if type is regular_file.
uint64_t length;
//only used if type is symlink.
utility::string target;
}; };
class file_system_instance { class file_system_instance {
@ -32,27 +42,21 @@ namespace mercury::kernel::storage {
public: public:
virtual ~file_system_instance() {} virtual ~file_system_instance() {}
virtual io_result get_root_node(node_id_t &out) = 0; virtual fs_result get_root_node(node_id_t &out) = 0;
//get_first_child sets iter_out to a "directory iterator" representing the //it is assumed that this is a directory. sets iter_out
//first child of this node. get_next_child gets the child after the child //to a value that can be passed to subsequent calls
//represented by the value of iter passed in, and changes iter to represent //to get_next_child with the same argument for node.
//that next child. for an empty directory node, get_first_child returns virtual fs_result get_first_child(node_id_t node, std::optional<dir_entry> &out, directory_iter_t &iter_out) = 0;
//io_result::not_found. when iter represents the last child of a node,
//get_next_child also returns io_result::not_found.
virtual io_result get_first_child(node_id_t node, node_id_t &out, directory_iter_t &iter_out) = 0;
virtual io_result get_next_child(node_id_t node, node_id_t &out, directory_iter_t &iter) = 0;
virtual io_result get_child(node_id_t node, node_id_t &out, const char *name, unsigned name_len) = 0;
virtual io_result get_name_length(node_id_t node, unsigned &length_out) = 0; //it is assumed that this is a directory. sets iter_out
//buffer is assumed to be long enough - call get_name_length first. //to a value that can be passed to subsequent calls
virtual io_result get_name(node_id_t node, char *buffer, unsigned &length_out) = 0; //to get_next_child with the same argument for node.
virtual io_result get_file_length(node_id_t node, uint64_t &length_out) = 0; virtual fs_result get_next_child(node_id_t node, std::optional<dir_entry> &out, directory_iter_t &iter) = 0;
virtual io_result get_file_type(node_id_t node, file_type &out) = 0;
virtual io_result resize_file(node_id_t node, uint64_t new_length) = 0; //it is assumed that this is a regular file and that
virtual io_result read_bytes_from_file(node_id_t node, uint64_t start, uint64_t count, void *into) = 0; //the region requested is within the bounds of the file.
virtual io_result write_bytes_into_file(node_id_t node, uint64_t start, uint64_t count, const void *from) = 0; virtual fs_result read_bytes_from_file(node_id_t node, uint64_t start, uint64_t count, void *into) = 0;
}; };
@ -61,27 +65,29 @@ namespace mercury::kernel::storage {
private: private:
uint8_t *block_cache; uint8_t *block_cache;
uint64_t block_cache_i; uint64_t block_cache_i;
bool block_cache_dirty;
io_result load_cache_block(uint64_t i); //it is assumed that this block is within the bounds of the device.
bd_result load_cache_block(uint64_t i);
protected: protected:
//implemented in driver, bounds not checked //implemented in driver. it is assumed that the
virtual io_result read_blocks_no_cache(uint64_t start, uint64_t count, void *into) = 0; //blocks are within the bounds of the device.
virtual io_result write_blocks_no_cache(uint64_t start, uint64_t count, const void *from) = 0; virtual bd_result read_blocks_no_cache(uint64_t start, uint64_t count, void *into) = 0;
//it is assumed that this is only called once, by the driver, after //it is assumed that this is only called once, by the driver, after
//block_size and block_count have been set, and before read_bytes or //block_size and block_count have been set, and before read_bytes or
//write_bytes can be called (e.g. in the derived class's constructor) //write_bytes can be called (e.g. in the derived class's constructor).
void allocate_block_cache(); void allocate_block_cache();
public: public:
//set by storage component //set by storage component
file_system_instance *mounted_as; file_system_instance *mounted_as;
//set by storage component
utility::uuid id; utility::uuid id;
//set by driver //set by driver
uint64_t block_size; uint64_t block_size;
//set by driver
uint64_t block_count; uint64_t block_count;
virtual ~block_device() { virtual ~block_device() {
@ -89,45 +95,10 @@ namespace mercury::kernel::storage {
delete block_cache; delete block_cache;
} }
io_result read_bytes(uint64_t start, uint64_t count, void *into); bd_result read_bytes(uint64_t start, uint64_t count, void *into);
io_result write_bytes(uint64_t start, uint64_t count, const void *from);
}; };
typedef io_result (*file_system_mounter)(block_device *bd, file_system_instance *&fs_out);
extern utility::list<block_device *> *block_devices;
void init_storage();
//a canon path contains no . or empty directory names, and
//contains no .. except for at the start of a relative path.
struct canon_path {
bool absolute;
unsigned parent_count;
utility::vector<utility::string> segments;
void parent();
void rel(const canon_path &r);
utility::string to_string(bool trailing_slash) const;
};
void canonize_path(const char *str, unsigned len, canon_path &out);
//path must be absolute.
io_result mount_device(block_device *bd, const canon_path &path, file_system_mounter mounter);
//path must be absolute. symlinks are always resolved on nodes other than the
//final one. they are resolved on the final node if and only if resolve final
//node is set to true. mount points are always traversed, including on the
//final node. this assumes that the path is under some mount point, and the
//same for any symlinks traversed (e.g. / is mounted).
io_result look_up_absolute_path(const canon_path &path, block_device *&bd_out,
node_id_t &node_out, bool resolve_final_node, canon_path &path_without_symlinks_out);
} }
#endif #endif

22
include/mercury/kernel/storage/bd/memory.hpp Normal file
View file

@ -0,0 +1,22 @@
#ifndef MERCURY_KERNEL_STORAGE_BD_MEMORY_HPP
#define MERCURY_KERNEL_STORAGE_BD_MEMORY_HPP
#include <mercury/kernel/storage.hpp>
namespace mercury::kernel::storage::bd {
class memory : public block_device {
private:
uint8_t *buffer;
public:
memory(void *buffer, uint64_t buffer_len);
bd_result read_blocks_no_cache(uint64_t start, uint64_t count, void *into) override;
};
}
#endif

32
include/mercury/kernel/storage/fs/tarfs.hpp Normal file
View file

@ -0,0 +1,32 @@
#ifndef MERCURY_KERNEL_STORAGE_FS_TARFS_HPP
#define MERCURY_KERNEL_STORAGE_FS_TARFS_HPP
#include <mercury/kernel/storage.hpp>
namespace mercury::kernel::storage::fs {
class tarfs_instance : public file_system_instance {
private:
block_device *bd;
fs_result next_node(node_id_t node, std::optional<node_id_t> &out);
fs_result read_full_name(node_id_t node, utility::string &out);
//len <= 12.
fs_result read_num(uint64_t offset, unsigned len, uint64_t &out);
fs_result first_child_starting_at(node_id_t parent, node_id_t start, std::optional<node_id_t> &out);
fs_result get_dir_entry(node_id_t node, dir_entry &entry);
public:
tarfs_instance(block_device *bd);
fs_result get_root_node(node_id_t &out);
fs_result get_first_child(node_id_t node, std::optional<dir_entry> &out, directory_iter_t &iter_out);
fs_result get_next_child(node_id_t node, std::optional<dir_entry> &out, directory_iter_t &iter);
fs_result read_bytes_from_file(node_id_t node, uint64_t start, uint64_t count, void *into);
};
}
#endif

4
include/mercury/kernel/terminal.hpp
View file

@ -1,6 +1,8 @@
#ifndef MERCURY_KERNEL_TERMINAL_HPP #ifndef MERCURY_KERNEL_TERMINAL_HPP
#define MERCURY_KERNEL_TERMINAL_HPP #define MERCURY_KERNEL_TERMINAL_HPP
#include <mercury/kernel/framebuffer.hpp>
#include <mercury/kernel/utility.hpp>
#include <cstddef> #include <cstddef>
#include <cstdint> #include <cstdint>
@ -21,7 +23,7 @@ namespace mercury::kernel::terminal {
extern framebuffer::color fg_color; extern framebuffer::color fg_color;
void put_char(char ch); void put_char(char ch);
void put_string(const char *str, size_t len); void put_string(const utility::string &str);
void put_string_sz(const char *str); void put_string_sz(const char *str);
void put_int_decimal(uint64_t n, bool with_commas = true); void put_int_decimal(uint64_t n, bool with_commas = true);

106
include/mercury/kernel/utility.hpp
View file

@ -106,6 +106,18 @@ namespace mercury::kernel::utility {
last = new_last; last = new_last;
} }
void remove(node *n) {
if (n->prev)
n->prev->next = n->next;
else
first = n->next;
if (n->next)
n->next->prev = n->prev;
else
last = n->prev;
delete n;
}
}; };
template <class value_t> template <class value_t>
@ -124,6 +136,14 @@ namespace mercury::kernel::utility {
buffer[i] = copy_from[i]; buffer[i] = copy_from[i];
} }
vector(const vector<value_t> &other)
: buffer(new value_t[other.buffer_len]),
buffer_len(other.buffer_len), count(other.count)
{
for (unsigned i = 0; i < count; ++i)
buffer[i] = other.buffer[i];
}
~vector() { ~vector() {
if (buffer) if (buffer)
delete[] buffer; delete[] buffer;
@ -134,6 +154,7 @@ namespace mercury::kernel::utility {
delete[] buffer; delete[] buffer;
buffer = new value_t[other.buffer_len]; buffer = new value_t[other.buffer_len];
buffer_len = other.buffer_len; buffer_len = other.buffer_len;
count = other.count;
for (unsigned i = 0; i < other.count; ++i) for (unsigned i = 0; i < other.count; ++i)
buffer[i] = other.buffer[i]; buffer[i] = other.buffer[i];
return *this; return *this;
@ -185,92 +206,19 @@ namespace mercury::kernel::utility {
++count; ++count;
} }
}; bool starts_with(const vector<value_t> &other) {
if (count < other.count)
typedef vector<char> string;
template <class key_component_t, class value_t>
struct trie {
typedef vector<key_component_t> key_t;
struct child {
key_component_t component;
trie tr;
};
//really this should be a hashmap or something
vector<child> children;
trie *try_get_child(const key_component_t &component) const {
for (unsigned i = 0; i < children.count; ++i)
if (children.buffer[i].component == component)
return &children.buffer[i].tr;
return 0;
}
std::optional<value_t> value_here;
trie() : children(0) {}
//prefix length is in key components, with the root node having a prefix
//length of 0. if no prefix of key has a value, then this just returns the
//root node and sets prefix length to 0.
const trie &longest_prefix_with_value(
const key_t &key, unsigned &prefix_length_out
) const {
const trie *on = this;
unsigned with_i = 0;
const trie *longest_found = this;
prefix_length_out = 0;
while (true) {
if (with_i == key.count)
return *longest_found;
on = on->try_get_child(key.buffer[with_i]);
if (!on)
return *longest_found;
++with_i;
if (on->value_here) {
longest_found = on;
prefix_length_out = with_i;
}
}
}
bool has_key(const key_t &key) {
const trie *on = this;
for (unsigned i = 0; i < key.count; ++i) {
on = on->try_get_child(key.buffer[i]);
if (!on)
return false; return false;
} for (unsigned i = 0; i < other.count; ++i)
return on->value_here.has_value(); if (buffer[i] != other.buffer[i])
}
//returns false if this key is already in use.
bool try_insert(const key_t &key, value_t value) {
trie *on = this;
for (unsigned i = 0; i < key.count; ++i) {
on = on->try_get_child(key.buffer[i]);
if (!on) {
child ch;
ch.component = key.buffer[i];
on->children.add_end(std::move(ch));
on = &on->children.buffer[on->children.count - 1].tr;
}
}
if (on->value_here)
return false; return false;
*on->value_here = value;
return true; return true;
} }
}; };
typedef vector<char> string;
} }
#endif #endif

62
include/mercury/kernel/vfile.hpp Normal file
View file

@ -0,0 +1,62 @@
#ifndef MERCURY_KERNEL_VFILE_HPP
#define MERCURY_KERNEL_VFILE_HPP
#include <mercury/kernel/storage.hpp>
#include <mercury/kernel/utility.hpp>
//TODO: mounts points.
//maybe a two-way map between mount points and targets? one mount point per
//target and vice versa. only directories may be mount points, and only file
//system roots (which must be directories) may be targets.
namespace mercury::kernel::vfile {
//a canon path contains no . or empty directory names, and
//contains no .. except for at the start of a relative path.
struct canon_path {
bool absolute;
unsigned parent_count;
utility::vector<utility::string> segments;
canon_path() : absolute(false), parent_count(0), segments(8) {}
void parent();
void rel(const canon_path &r);
utility::string to_string(bool trailing_slash) const;
};
void canonize_path(const utility::string &name, canon_path &out);
struct vfile {
//on followed symlinks, path is the source of the symlink and the
//rest of these are the target. in any case, path should be absolute.
canon_path path;
storage::block_device *bd;
storage::dir_entry dir_entry;
//TODO: instead of passing root, use saved mount points.
storage::fs_result follow_symlinks(
const vfile &root, std::optional<vfile> &out) const;
//dir_entry.type is assumed to be directory.
storage::fs_result get_child(
std::optional<vfile> &out, const utility::string &name) const;
//dir_entry.type is assumed to be directory. out must be empty on entry.
storage::fs_result get_children(utility::vector<vfile> &out) const;
};
//path must be absolute. follows symlinks on all but the last node.
//relative_to should be a directory to do the lookup inside; e.g.,
//if relative_to is /a/b and path is c, then out becomes /a/b/c.
//TODO: instead of passing root, use saved mount points.
storage::fs_result lookup_path(
const vfile &root, const canon_path &path, std::optional<vfile> &out);
}
#endif

27
kernel/bd/memory.cpp
View file

@ -1,27 +0,0 @@
#include <mercury/kernel/bd/memory.hpp>
namespace mercury::kernel::bd {
memory::memory(void *buffer, size_t buffer_len) : buffer((uint8_t *)buffer) {
block_size = 1;
block_count = buffer_len;
//block cache will never be used, since the block size is 1.
}
storage::io_result memory::read_blocks_no_cache(
uint64_t start, uint64_t count, void *into
) {
for (uint64_t i = 0; i < count; ++i)
((uint8_t *)into)[i] = buffer[start + i];
return storage::io_result::success;
}
storage::io_result memory::write_blocks_no_cache(
uint64_t start, uint64_t count, const void *into
) {
for (uint64_t i = 0; i < count; ++i)
buffer[start + i] = ((uint8_t *)into)[i];
return storage::io_result::success;
}
}

149
kernel/entry.cpp
View file

@ -1,9 +1,10 @@
#include <mercury/kernel/storage/bd/memory.hpp>
#include <mercury/kernel/storage/fs/tarfs.hpp>
#include <mercury/kernel/framebuffer.hpp> #include <mercury/kernel/framebuffer.hpp>
#include <mercury/kernel/bd/memory.hpp>
#include <mercury/kernel/fs/tarfs.hpp>
#include <mercury/kernel/terminal.hpp> #include <mercury/kernel/terminal.hpp>
#include <mercury/kernel/limine.hpp> #include <mercury/kernel/limine.hpp>
#include <mercury/kernel/paging.hpp> #include <mercury/kernel/paging.hpp>
#include <mercury/kernel/vfile.hpp>
using namespace mercury::kernel; using namespace mercury::kernel;
@ -182,78 +183,67 @@ extern "C" [[noreturn]] void entry() {
[[noreturn]] static void print_and_halt(const char *msg) { [[noreturn]] static void print_and_halt(const char *msg) {
terminal::put_string_sz(msg); terminal::put_string_sz(msg);
while (1) while (1)
; asm ("hlt");
}
static void draw_indent(unsigned indent) {
for (unsigned i = 0; i < indent; ++i)
terminal::put_char(' ');
} }
static void dir_tree( static void dir_tree(
storage::block_device *bd, storage::node_id_t node, unsigned indent const vfile::vfile &root, const vfile::vfile &f, unsigned indent
) { ) {
storage::node_id_t child_node; draw_indent(indent);
storage::directory_iter_t dir_iter; terminal::put_string(f.dir_entry.name);
storage::io_result result =
bd->mounted_as->get_first_child(node, child_node, dir_iter);
if (result == storage::io_result::not_found) {
for (unsigned i = 0; i < indent; ++i)
terminal::put_char(' ');
terminal::put_string_sz("[empty]\n");
return;
}
else if (result)
print_and_halt("error getting first child.");
while (true) {
unsigned name_len;
if (bd->mounted_as->get_name_length(child_node, name_len))
print_and_halt("failed to get name length.");
char *name_buf = new char[name_len];
if (bd->mounted_as->get_name(child_node, name_buf, name_len))
print_and_halt("failed to get name.");
for (unsigned i = 0; i < indent; ++i)
terminal::put_char(' ');
terminal::put_string(name_buf, name_len);
terminal::put_string(":\n", 2);
delete[] name_buf;
storage::file_type type;
if (bd->mounted_as->get_file_type(child_node, type))
print_and_halt("failed to get type.");
if (type == storage::file_type::directory)
dir_tree(bd, child_node, indent + 2);
else {
uint64_t len;
if (bd->mounted_as->get_file_length(child_node, len))
print_and_halt("failed to get length.");
char *contents = new char[len];
if (bd->mounted_as->read_bytes_from_file(child_node, 0, len, contents))
print_and_halt("failed to read file.");
if (contents[len - 1] == '\n')
len--;
for (unsigned i = 0; i < indent + 2; ++i)
terminal::put_char(' ');
if (len == 0)
terminal::put_string_sz("[empty]\n");
else {
terminal::put_string(contents, len);
terminal::put_char('\n'); terminal::put_char('\n');
}
delete[] contents; std::optional<vfile::vfile> followed;
} utility::vector<vfile::vfile> children;
storage::io_result result switch (f.dir_entry.type) {
= bd->mounted_as->get_next_child(node, child_node, dir_iter);
if (result == storage::io_result::not_found) case storage::file_type::regular_file:
return; draw_indent(indent + 2);
else if (result) terminal::put_string_sz("type: regular file\n");
print_and_halt("error getting next child."); draw_indent(indent + 2);
terminal::put_string_sz("length: ");
terminal::put_int_decimal(f.dir_entry.length);
terminal::put_string_sz(" bytes\n");
break;
case storage::file_type::symlink:
draw_indent(indent + 2);
terminal::put_string_sz("type: symlink\n");
draw_indent(indent + 2);
terminal::put_string_sz("target: ");
terminal::put_string(f.dir_entry.target);
terminal::put_char('\n');
if (f.follow_symlinks(root, followed) != storage::fs_result::success)
print_and_halt("failed to follow symlink.");
if (!followed) {
draw_indent(indent + 4);
terminal::put_string_sz("[broken]\n");
}
dir_tree(root, *followed, indent + 4);
break;
case storage::file_type::directory:
if (f.get_children(children) != storage::fs_result::success)
print_and_halt("failed to get children.");
draw_indent(indent + 2);
terminal::put_string_sz("type: directory\n");
draw_indent(indent + 2);
terminal::put_string_sz("children:\n");
if (children.count == 0) {
draw_indent(indent + 4);
terminal::put_string_sz("[empty]\n");
}
else
for (unsigned i = 0; i < children.count; ++i)
dir_tree(root, children.buffer[i], indent + 4);
break;
} }
@ -262,16 +252,10 @@ static void dir_tree(
[[noreturn]] static void with_kernel_p4() { [[noreturn]] static void with_kernel_p4() {
terminal::init_terminal(); terminal::init_terminal();
storage::init_storage();
storage::block_device *initfs_bd = new bd::memory(initfs, initfs_len); storage::bd::memory initfs_bd(initfs, initfs_len);
storage::block_devices->insert_end(initfs_bd); storage::fs::tarfs_instance initfs_fs(&initfs_bd);
initfs_bd.mounted_as = &initfs_fs;
storage::canon_path root;
storage::canonize_path("/", 1, root);
if (storage::mount_device(initfs_bd, root, &fs::tarfs_mounter))
print_and_halt("failed to mount initfs.");
terminal::put_string_sz("kernel initialization complete.\n"); terminal::put_string_sz("kernel initialization complete.\n");
@ -283,12 +267,17 @@ static void dir_tree(
terminal::put_int_decimal(free_pram_kib); terminal::put_int_decimal(free_pram_kib);
terminal::put_string_sz(" kiB physical memory free.\n"); terminal::put_string_sz(" kiB physical memory free.\n");
storage::node_id_t root_node; vfile::vfile root;
if (initfs_bd->mounted_as->get_root_node(root_node)) root.bd = &initfs_bd;
print_and_halt("failed to get root initfs node."); root.dir_entry.type = storage::file_type::directory;
root.path.absolute = true;
terminal::put_string_sz("initfs:\n"); if (initfs_fs.get_root_node(root.dir_entry.node) !=
dir_tree(initfs_bd, root_node, 2); storage::fs_result::success)
print_and_halt("failed to get root node.");
terminal::put_string_sz("initfs");
dir_tree(root, root, 0);
print_and_halt("halting."); print_and_halt("halting.");
} }

296
kernel/fs/tarfs.cpp
View file

@ -1,296 +0,0 @@
#include <mercury/kernel/fs/tarfs.hpp>
//in fs::tarfs_instance, storage::node_id_t refers to the number
//of bytes into the block device that the info sector is located
namespace mercury::kernel::fs {
storage::io_result tarfs_mounter(
storage::block_device *bd, storage::file_system_instance *&fs_out
) {
fs_out = new tarfs_instance(bd);
return storage::io_result::success;
}
tarfs_instance::tarfs_instance(storage::block_device *bd) : bd(bd) {}
storage::io_result tarfs_instance::next_node(storage::node_id_t &node) {
uint64_t file_length;
storage::io_result result = read_num(node + 124, 12, file_length);
if (result != storage::io_result::success)
return result;
node += ((file_length - 1) / 512 + 2) * 512;
uint8_t sector[512];
result = bd->read_bytes(node, 512, sector);
if (result != storage::io_result::success)
return result;
for (unsigned i = 0; i < 512; ++i)
if (sector[i] != 0)
return storage::io_result::success;
return storage::io_result::out_of_bounds;
}
storage::io_result tarfs_instance::read_name(
storage::node_id_t node, char *name_buf, unsigned &name_len_out
) {
name_len_out = 0;
storage::io_result result = bd->read_bytes(node + 345, 155, name_buf);
if (result != storage::io_result::success)
return result;
while (name_buf[name_len_out] && name_len_out < 155)
++name_len_out;
result = bd->read_bytes(node, 100, name_buf + name_len_out);
if (result != storage::io_result::success)
return result;
unsigned new_limit = name_len_out + 100;
while (name_buf[name_len_out] && name_len_out < new_limit)
++name_len_out;
return storage::io_result::success;
}
storage::io_result tarfs_instance::read_num(
uint64_t offset, unsigned len, uint64_t &out
) {
//len <= 12
char buffer[12];
storage::io_result result = bd->read_bytes(offset, len, buffer);
if (result != storage::io_result::success)
return result;
out = 0;
for (unsigned i = 0; i < len; ++i) {
if (!buffer[i])
return i == 0 ? storage::io_result::fs_corrupt
: storage::io_result::success;
if (buffer[i] < '0' || buffer[i] > '7')
return storage::io_result::fs_corrupt;
out = out * 8 + buffer[i] - '0';
}
return storage::io_result::success;
}
#define RETURN_MAYBE_NOT_FOUND(expr) \
{ \
storage::io_result _result = expr; \
if (_result == storage::io_result::out_of_bounds) \
return storage::io_result::not_found; \
if (_result != storage::io_result::success) \
return _result; \
}
#define RETURN_NOT_SUCCESS(expr) \
{ \
storage::io_result _result = expr; \
if (_result != storage::io_result::success) \
return _result; \
}
storage::io_result tarfs_instance::get_root_node(storage::node_id_t &out) {
out = 0;
while (true) {
char name_buf[255];
unsigned name_len;
RETURN_MAYBE_NOT_FOUND(read_name(out, name_buf, name_len))
if (name_len == 2 && name_buf[0] == '.' && name_buf[1] == '/')
return storage::io_result::success;
RETURN_MAYBE_NOT_FOUND(next_node(out))
}
}
storage::io_result tarfs_instance::get_first_child(storage::node_id_t node,
storage::node_id_t &out, storage::directory_iter_t &iter_out
) {
char name_buf[255];
unsigned name_len;
RETURN_NOT_SUCCESS(read_name(node, name_buf, name_len))
out = 0;
while (true) {
char cand_name_buf[255];
unsigned cand_name_len;
RETURN_MAYBE_NOT_FOUND(read_name(out, cand_name_buf, cand_name_len))
if (cand_name_len > name_len && utility::starts_with(
cand_name_buf, cand_name_len, name_buf, name_len
)) {
const char *rem = cand_name_buf + name_len;
unsigned rem_len = cand_name_len - name_len;
unsigned slash = utility::find(rem, rem_len, '/');
if (slash == rem_len - 1 || slash == rem_len) {
iter_out = out;
return storage::io_result::success;
}
}
RETURN_MAYBE_NOT_FOUND(next_node(out))
}
}
storage::io_result tarfs_instance::get_next_child(storage::node_id_t node,
storage::node_id_t &out, storage::directory_iter_t &iter
) {
char name_buf[255];
unsigned name_len;
RETURN_NOT_SUCCESS(read_name(node, name_buf, name_len))
out = iter;
RETURN_MAYBE_NOT_FOUND(next_node(out))
while (true) {
char cand_name_buf[255];
unsigned cand_name_len;
RETURN_MAYBE_NOT_FOUND(read_name(out, cand_name_buf, cand_name_len))
if (cand_name_len > name_len && utility::starts_with(
cand_name_buf, cand_name_len, name_buf, name_len
)) {
const char *rem = cand_name_buf + name_len;
unsigned rem_len = cand_name_len - name_len;
unsigned slash = utility::find(rem, rem_len, '/');
if (slash == rem_len - 1 || slash == rem_len) {
iter = out;
return storage::io_result::success;
}
}
RETURN_MAYBE_NOT_FOUND(next_node(out))
}
}
storage::io_result tarfs_instance::get_child(storage::node_id_t node,
storage::node_id_t &out, const char *name, unsigned name_len
) {
char full_name[255];
unsigned full_name_len;
RETURN_MAYBE_NOT_FOUND(read_name(node, full_name, full_name_len))
if (full_name_len + name_len > 255)
return storage::io_result::not_supported;
for (unsigned i = 0; i < name_len; ++i)
full_name[full_name_len + i] = name[i];
full_name_len += name_len;
out = 0;
while (true) {
char cand_name[255];
unsigned cand_name_len;
RETURN_MAYBE_NOT_FOUND(read_name(out, cand_name, cand_name_len))
if (cand_name_len != full_name_len && cand_name_len != full_name_len + 1)
goto next_iter;
for (unsigned i = 0; i < full_name_len; ++i)
if (cand_name[i] != full_name[i])
goto next_iter;
if (cand_name_len == full_name_len + 1 &&
cand_name[full_name_len] != '/')
goto next_iter;
return storage::io_result::success;
next_iter:
RETURN_MAYBE_NOT_FOUND(next_node(out))
}
}
storage::io_result tarfs_instance::get_name_length(
storage::node_id_t node, unsigned &length_out
) {
char name_buf[255];
return get_name(node, name_buf, length_out);
}
storage::io_result tarfs_instance::get_name(
storage::node_id_t node, char *buffer, unsigned &length_out
) {
unsigned full_length;
char full_buffer[255];
RETURN_NOT_SUCCESS(read_name(node, full_buffer, full_length))
if (full_length == 2) {
//full buffer must be ./
length_out = 0;
return storage::io_result::success;
}
if (full_buffer[full_length - 1] == '/')
--full_length;
unsigned start = utility::find_last(full_buffer, full_length, '/') + 1;
length_out = full_length - start;
for (unsigned i = 0; i < length_out; ++i)
buffer[i] = full_buffer[start + i];
return storage::io_result::success;
}
storage::io_result tarfs_instance::get_file_length(
storage::node_id_t node, uint64_t &length_out
) {
return read_num(node + 124, 12, length_out);
}
storage::io_result tarfs_instance::get_file_type(
storage::node_id_t node, storage::file_type &out
) {
uint64_t ft;
storage::io_result result = read_num(node + 156, 1, ft);
if (result != storage::io_result::success)
return result;
switch (ft) {
case 0:
out = storage::file_type::regular_file;
return storage::io_result::success;
case 2:
out = storage::file_type::symlink;
return storage::io_result::success;
case 5:
out = storage::file_type::directory;
return storage::io_result::success;
default:
return storage::io_result::not_supported;
}
}
storage::io_result tarfs_instance::resize_file(
storage::node_id_t, uint64_t
) {
//TODO: support resize if sector count isn't changed?
return storage::io_result::not_supported;
}
storage::io_result tarfs_instance::read_bytes_from_file(
storage::node_id_t node, uint64_t start, uint64_t count, void *into
) {
return bd->read_bytes(node + 512 + start, count, into);
}
storage::io_result tarfs_instance::write_bytes_into_file(
storage::node_id_t, uint64_t, uint64_t, const void *
) {
//TODO: support this.
return storage::io_result::not_supported;
}
}

225
kernel/storage.cpp
View file

@ -1,49 +1,38 @@
#include <mercury/kernel/storage.hpp> #include <mercury/kernel/storage.hpp>
#define RETURN_IF_NOT_SUCCESS(expr) \
{ \
io_result _result = expr; \
if (_result != io_result::success) \
return _result; \
}
namespace mercury::kernel::storage { namespace mercury::kernel::storage {
io_result block_device::load_cache_block(uint64_t i) { bd_result block_device::load_cache_block(uint64_t i) {
if (block_cache_i == i) if (block_cache_i == i)
return io_result::success; return bd_result::success;
if (block_cache_dirty) { bd_result result = read_blocks_no_cache(i, 1, block_cache);
RETURN_IF_NOT_SUCCESS(
write_blocks_no_cache(block_cache_i, 1, block_cache))
block_cache_dirty = false;
}
io_result result = read_blocks_no_cache(i, 1, block_cache); if (result != bd_result::success) {
if (result != io_result::success) {
block_cache_i = block_count; block_cache_i = block_count;
return result; return result;
} }
block_cache_i = i; block_cache_i = i;
return io_result::success; return bd_result::success;
} }
io_result block_device::read_bytes( bd_result block_device::read_bytes(
uint64_t start, uint64_t count, void *into uint64_t start, uint64_t count, void *into
) { ) {
if (start + count > block_size * block_count) if (start + count > block_size * block_count)
return io_result::out_of_bounds; return bd_result::out_of_bounds;
uint8_t *into_u8 = (uint8_t *)into; uint8_t *into_u8 = (uint8_t *)into;
if (start % block_size != 0) { if (start % block_size != 0) {
uint64_t prefix_len = block_size - start % block_size; uint64_t prefix_len = block_size - start % block_size;
RETURN_IF_NOT_SUCCESS(load_cache_block(start / block_size)) bd_result result = load_cache_block(start / block_size);
if (result != bd_result::success)
return result;
for (uint64_t i = 0; i < prefix_len; ++i) for (uint64_t i = 0; i < prefix_len; ++i)
into_u8[i] = block_cache[start % block_size + i]; into_u8[i] = block_cache[start % block_size + i];
into_u8 += prefix_len; into_u8 += prefix_len;
@ -54,202 +43,24 @@ namespace mercury::kernel::storage {
uint64_t postfix_start = ((start + count) / block_size) * block_size; uint64_t postfix_start = ((start + count) / block_size) * block_size;
if (postfix_start != start) { if (postfix_start != start) {
RETURN_IF_NOT_SUCCESS(read_blocks_no_cache( bd_result result = read_blocks_no_cache(
start / block_size, (postfix_start - start) / block_size, into_u8)) start / block_size, (postfix_start - start) / block_size, into_u8);
if (result != bd_result::success)
return result;
count -= postfix_start - start; count -= postfix_start - start;
into_u8 += postfix_start - start; into_u8 += postfix_start - start;
start = postfix_start; start = postfix_start;
} }
if (count != 0) { if (count != 0) {
RETURN_IF_NOT_SUCCESS(load_cache_block(start / block_size)) bd_result result = load_cache_block(start / block_size);
if (result != bd_result::success)
return result;
for (uint64_t i = 0; i < count; ++i) for (uint64_t i = 0; i < count; ++i)
into_u8[i] = block_cache[i]; into_u8[i] = block_cache[i];
} }
return io_result::success; return bd_result::success;
}
utility::list<block_device *> *block_devices;
static utility::trie<utility::string, block_device *> *mounted_devices;
void init_storage() {
block_devices = new utility::list<block_device *>();
mounted_devices = new utility::trie<utility::string, block_device *>();
}
void canon_path::parent() {
if (segments.count != 0)
--segments.count;
else if (!absolute)
++parent_count;
}
void canon_path::rel(const canon_path &r) {
if (r.absolute) {
segments.count = 0;
absolute = true;
parent_count = 0;
}
for (unsigned i = 0; i < r.parent_count; ++i)
parent();
for (unsigned i = 0; i < r.segments.count; ++i)
segments.add_end(r.segments.buffer[i]);
}
void canonize_path(const char *str, unsigned len, canon_path &out) {
out.absolute = false;
out.parent_count = 0;
out.segments.count = 0;
if (len == 0)
return;
if (len == 1 && str[0] == '/') {
out.absolute = true;
return;
}
if (str[0] == '/') {
out.absolute = true;
++str;
--len;
}
while (len != 0) {
unsigned segment_len = utility::find(str, len, '/');
unsigned to_skip = segment_len == len ? segment_len : segment_len + 1;
if (segment_len == 0)
;
else if (segment_len == 1 && str[0] == '.')
;
else if (segment_len == 2 && str[0] == '.' && str[1] == '.')
out.parent();
else {
utility::string segment(str, segment_len);
out.segments.add_end(std::move(segment));
}
str += to_skip;
len -= to_skip;
}
}
io_result mount_device(
block_device *bd, const canon_path &path, file_system_mounter mounter
) {
if (!path.absolute)
return io_result::bad_path;
if (mounted_devices->has_key(path.segments))
return io_result::mount_point_already_used;
file_system_instance *fs;
RETURN_IF_NOT_SUCCESS(mounter(bd, fs));
bd->mounted_as = fs;
mounted_devices->try_insert(path.segments, bd);
return io_result::success;
}
static io_result symlink_contents(
block_device *bd, node_id_t node, canon_path &out
) {
//TODO
while (1)
;
(void)bd;
(void)node;
(void)out;
}
static io_result resolve_symlinks(
block_device *&bd, node_id_t &node, canon_path &path
) {
file_type ft;
RETURN_IF_NOT_SUCCESS(bd->mounted_as->get_file_type(node, ft))
if (ft != file_type::symlink)
return io_result::success;
canon_path contents;
RETURN_IF_NOT_SUCCESS(symlink_contents(bd, node, contents))
path.parent();
path.rel(contents);
return look_up_absolute_path(path, bd, node, true, path);
}
io_result look_up_absolute_path(const canon_path &path,
block_device *&bd_out, node_id_t &node_out, bool resolve_final_node,
canon_path &path_without_symlinks_out
) {
if (!path.absolute)
return io_result::bad_path;
unsigned prefix_length;
bd_out =
*mounted_devices->longest_prefix_with_value(path.segments, prefix_length)
.value_here;
RETURN_IF_NOT_SUCCESS(bd_out->mounted_as->get_root_node(node_out))
path_without_symlinks_out.absolute = true;
path_without_symlinks_out.parent_count = 0;
path_without_symlinks_out.segments.count = 0;
for (unsigned i = 0; i < prefix_length; ++i)
path_without_symlinks_out.segments.add_end(path.segments.buffer[i]);
if (path.segments.count == 0)
goto on_final_node;
for (unsigned i = prefix_length; i < path.segments.count - 1; ++i) {
path_without_symlinks_out.segments.add_end(path.segments.buffer[i]);
RETURN_IF_NOT_SUCCESS(bd_out->mounted_as->get_child(node_out, node_out,
path.segments.buffer[i].buffer, path.segments.buffer[i].count))
RETURN_IF_NOT_SUCCESS(resolve_symlinks(
bd_out, node_out, path_without_symlinks_out))
file_type ft;
RETURN_IF_NOT_SUCCESS(bd_out->mounted_as->get_file_type(node_out, ft))
if (ft != file_type::directory)
return io_result::not_a_directory;
}
{
//in a block so that compiler sees last_segment
//isn't needed after this and allows the goto above.
const utility::string &last_segment =
path.segments.buffer[path.segments.count - 1];
path_without_symlinks_out.segments.add_end(last_segment);
RETURN_IF_NOT_SUCCESS(bd_out->mounted_as->get_child(
node_out, node_out, last_segment.buffer, last_segment.count))
}
on_final_node:
if (resolve_final_node)
RETURN_IF_NOT_SUCCESS(resolve_symlinks(
bd_out, node_out, path_without_symlinks_out))
return io_result::success;
} }

21
kernel/storage/bd/memory.cpp Normal file
View file

@ -0,0 +1,21 @@
#include <mercury/kernel/storage/bd/memory.hpp>
namespace mercury::kernel::storage::bd {
memory::memory(void *buffer, uint64_t buffer_len)
: buffer((uint8_t *)buffer)
{
block_size = 1;
block_count = buffer_len;
//block cache will never be used, since the block size is 1.
}
bd_result memory::read_blocks_no_cache(
uint64_t start, uint64_t count, void *into
) {
for (uint64_t i = 0; i < count; ++i)
((uint8_t *)into)[i] = buffer[start + i];
return bd_result::success;
}
}

254
kernel/storage/fs/tarfs.cpp Normal file
View file

@ -0,0 +1,254 @@
#include <mercury/kernel/storage/fs/tarfs.hpp>
//in tarfs_instance, node_id_t and directory_iter_t refer to the number
//of bytes into the block device that the info sector is located.
namespace mercury::kernel::storage::fs {
#define BD_TO_FS(expr) \
{ \
bd_result _result = expr; \
if (_result == bd_result::out_of_bounds) \
return fs_result::fs_corrupt; \
if (_result == bd_result::device_error) \
return fs_result::device_error; \
}
#define FS_TO_FS(expr) \
{ \
fs_result _result = expr; \
if (_result != fs_result::success) \
return _result; \
}
tarfs_instance::tarfs_instance(block_device *bd) : bd(bd) {}
fs_result tarfs_instance::next_node(
node_id_t node, std::optional<node_id_t> &out
) {
uint64_t bytes;
FS_TO_FS(read_num(node + 124, 12, bytes))
out = node + ((bytes - 1) / 512 + 2) * 512;
uint8_t sector[512];
BD_TO_FS(bd->read_bytes(node, 512, sector))
for (unsigned i = 0; i < 512; ++i)
if (sector[i] != 0)
return fs_result::success;
out = {};
return fs_result::success;
}
fs_result tarfs_instance::read_full_name(
node_id_t node, utility::string &out
) {
out.count = 0;
out.verify_buffer_len(155);
BD_TO_FS(bd->read_bytes(node + 345, 155, out.buffer))
while (out.count < 155 && out.buffer[out.count] != '\0')
++out.count;
unsigned new_max = out.count + 100;
out.verify_buffer_len(new_max);
BD_TO_FS(bd->read_bytes(node, 100, out.buffer + out.count))
while (out.count < 255 && out.buffer[out.count] != '\0')
++out.count;
return fs_result::success;
}
//len <= 12.
fs_result tarfs_instance::read_num(
uint64_t offset, unsigned len, uint64_t &out
) {
char buf[12];
BD_TO_FS(bd->read_bytes(offset, len, buf))
out = 0;
for (unsigned i = 0; i < len && buf[i] != '\0'; ++i) {
if (buf[i] < '0' || buf[i] > '7')
return fs_result::fs_corrupt;
out = out * 8 + buf[i] - '0';
}
return fs_result::success;
}
fs_result tarfs_instance::first_child_starting_at(
node_id_t parent, node_id_t start, std::optional<node_id_t> &out
) {
utility::string parent_full_name;
FS_TO_FS(read_full_name(parent, parent_full_name))
utility::string child_full_name;
out = start;
do {
FS_TO_FS(read_full_name(*out, child_full_name))
if (child_full_name.count > parent_full_name.count &&
child_full_name.starts_with(parent_full_name)
) {
if (child_full_name.buffer[child_full_name.count - 1] == '/')
--child_full_name.count;
for (unsigned i = parent_full_name.count;
i < child_full_name.count; ++i)
if (child_full_name.buffer[i] == '/')
goto next;
return fs_result::success;
}
next:
next_node(*out, out);
} while (out);
return fs_result::success;
}
fs_result tarfs_instance::get_dir_entry(node_id_t node, dir_entry &entry) {
utility::string full_name;
read_full_name(node, full_name);
if (full_name.count == 2)
entry.name.count = 0;
else {
if (full_name.buffer[full_name.count - 1] == '/')
--full_name.count;
unsigned last_slash =
utility::find_last(full_name.buffer, full_name.count, '/');
entry.name.count = full_name.count - last_slash - 1;
entry.name.verify_buffer_len(entry.name.count);
for (unsigned i = 0; i < entry.name.count; ++i)
entry.name.buffer[i] = full_name.buffer[last_slash + 1 + i];
}
entry.node = node;
char ch;
BD_TO_FS(bd->read_bytes(node + 156, 1, &ch));
switch (ch) {
case '0':
entry.type = file_type::regular_file;
break;
case '2':
entry.type = file_type::symlink;
break;
case '5':
entry.type = file_type::directory;
break;
default:
return fs_result::fs_corrupt;
}
if (entry.type == file_type::regular_file) {
uint64_t length;
FS_TO_FS(read_num(node + 124, 12, length))
entry.length = length;
}
else if (entry.type == file_type::symlink) {
utility::string target;
target.verify_buffer_len(100);
BD_TO_FS(bd->read_bytes(node + 157, 100, target.buffer))
while (target.count < 100 && target.buffer[target.count] != '\0')
++target.count;
entry.target = std::move(target);
}
return fs_result::success;
}
fs_result tarfs_instance::get_root_node(node_id_t &out) {
utility::string full_name;
std::optional<node_id_t> on = 0;
do {
FS_TO_FS(read_full_name(*on, full_name))
if (full_name.count == 2) {
out = *on;
return fs_result::success;
}
next_node(*on, on);
} while (on);
return fs_result::fs_corrupt;
}
fs_result tarfs_instance::get_first_child(
node_id_t node, std::optional<dir_entry> &out, directory_iter_t &iter_out
) {
std::optional<node_id_t> child;
FS_TO_FS(first_child_starting_at(node, 0, child))
if (!child) {
out = {};
return fs_result::success;
}
dir_entry entry;
FS_TO_FS(get_dir_entry(*child, entry))
out = std::move(entry);
iter_out = (directory_iter_t)*child;
return fs_result::success;
}
fs_result tarfs_instance::get_next_child(
node_id_t node, std::optional<dir_entry> &out, directory_iter_t &iter
) {
std::optional<node_id_t> start;
FS_TO_FS(next_node((node_id_t)iter, start))
if (!start) {
out = {};
return fs_result::success;
}
std::optional<node_id_t> child;
FS_TO_FS(first_child_starting_at(node, *start, child))
if (!child) {
out = {};
return fs_result::success;
}
dir_entry entry;
FS_TO_FS(get_dir_entry(*child, entry))
out = std::move(entry);
iter = (directory_iter_t)*child;
return fs_result::success;
}
fs_result tarfs_instance::read_bytes_from_file(
node_id_t node, uint64_t start, uint64_t count, void *into
) {
BD_TO_FS(bd->read_bytes(node + 512 + start, count, into))
return fs_result::success;
}
}

6
kernel/terminal.cpp
View file

@ -74,9 +74,9 @@ namespace mercury::kernel::terminal {
} }
} }
void put_string(const char *str, size_t len) { void put_string(const utility::string &str) {
for (size_t i = 0; i < len; ++i) for (size_t i = 0; i < str.count; ++i)
put_char(str[i]); put_char(str.buffer[i]);
} }
void put_string_sz(const char *str) { void put_string_sz(const char *str) {

192
kernel/vfile.cpp Normal file
View file

@ -0,0 +1,192 @@
#include <mercury/kernel/vfile.hpp>
//TODO: handle symlink loops nicely in vfile::get_child,
// vfile::get_children, and lookup_path.
namespace mercury::kernel::vfile {
void canon_path::parent() {
if (segments.count != 0)
--segments.count;
else if (!absolute)
++parent_count;
}
void canon_path::rel(const canon_path &r) {
if (r.absolute) {
segments.count = 0;
absolute = true;
parent_count = 0;
}
for (unsigned i = 0; i < r.parent_count; ++i)
parent();
for (unsigned i = 0; i < r.segments.count; ++i)
segments.add_end(r.segments.buffer[i]);
}
void canonize_path(const utility::string &name, canon_path &out) {
out.absolute = false;
out.parent_count = 0;
out.segments.count = 0;
const char *str = name.buffer;
unsigned len = name.count;
if (len == 0)
return;
if (len == 1 && str[0] == '/') {
out.absolute = true;
return;
}
if (str[0] == '/') {
out.absolute = true;
++str;
--len;
}
while (len != 0) {
unsigned segment_len = utility::find(str, len, '/');
unsigned to_skip = segment_len == len ? segment_len : segment_len + 1;
if (segment_len == 0)
;
else if (segment_len == 1 && str[0] == '.')
;
else if (segment_len == 2 && str[0] == '.' && str[1] == '.')
out.parent();
else {
utility::string segment(str, segment_len);
out.segments.add_end(std::move(segment));
}
str += to_skip;
len -= to_skip;
}
}
#define RET_NOT_SUC(expr) \
{ \
storage::fs_result _result = expr; \
if (_result != storage::fs_result::success) \
return _result; \
}
storage::fs_result vfile::follow_symlinks(
const vfile &root, std::optional<vfile> &out
) const {
if (dir_entry.type != storage::file_type::symlink) {
out = *this;
return storage::fs_result::success;
}
canon_path target_path;
canonize_path(dir_entry.target, target_path);
canon_path full_path = path;
full_path.parent();
full_path.rel(target_path);
std::optional<vfile> next;
RET_NOT_SUC(lookup_path(root, full_path, next))
if (!next) {
out = {};
return storage::fs_result::success;
}
next->path = path;
return next->follow_symlinks(root, out);
}
storage::fs_result vfile::get_child(
std::optional<vfile> &out, const utility::string &name
) const {
std::optional<storage::dir_entry> entry;
storage::directory_iter_t iter;
RET_NOT_SUC(bd->mounted_as->get_first_child(dir_entry.node, entry, iter))
while (entry) {
if (entry->name == name) {
vfile vf;
vf.bd = bd;
vf.dir_entry = std::move(*entry);
vf.path = path;
vf.path.segments.add_end(name);
out = std::move(vf);
return storage::fs_result::success;
}
RET_NOT_SUC(bd->mounted_as->get_next_child(dir_entry.node, entry, iter))
}
out = {};
return storage::fs_result::success;
}
storage::fs_result vfile::get_children(utility::vector<vfile> &out) const {
std::optional<storage::dir_entry> entry;
storage::directory_iter_t iter;
RET_NOT_SUC(bd->mounted_as->get_first_child(dir_entry.node, entry, iter))
while (entry) {
vfile vf;
vf.bd = bd;
vf.path = path;
vf.path.segments.add_end(entry->name);
vf.dir_entry = std::move(*entry);
out.add_end(std::move(vf));
RET_NOT_SUC(bd->mounted_as->get_next_child(dir_entry.node, entry, iter))
}
return storage::fs_result::success;
}
storage::fs_result lookup_path(
const vfile &root, const canon_path &path, std::optional<vfile> &out
) {
//assume path is absolute.
out = root;
for (unsigned i = 0; i < path.segments.count; ++i) {
std::optional<vfile> result;
RET_NOT_SUC(out->follow_symlinks(root, result))
out = std::move(result);
if (!out)
return storage::fs_result::success;
RET_NOT_SUC(out->get_child(result, path.segments.buffer[i]))
out = std::move(result);
if (!out)
return storage::fs_result::success;
}
return storage::fs_result::success;
}
}

5
makefile
View file

@ -1,6 +1,6 @@
GPP_ARGS = -Wall -Wextra -O3 -ggdb -I include -ffreestanding -fno-exceptions -fno-rtti -mno-sse GPP_ARGS = -Wall -Wextra -O3 -ggdb -I include -ffreestanding -fno-exceptions -fno-rtti -mno-sse
KERNEL_OBJECTS = allocator.cpp entry.cpp framebuffer.cpp paging.asm \ KERNEL_OBJECTS = allocator.cpp entry.cpp framebuffer.cpp paging.asm paging.cpp storage.cpp \
paging.cpp storage.cpp terminal.cpp utility.cpp bd/memory.cpp fs/tarfs.cpp storage/bd/memory.cpp storage/fs/tarfs.cpp terminal.cpp utility.cpp vfile.cpp
all: out/disk.iso all: out/disk.iso
@ -39,6 +39,7 @@ obj/initfs.tgz:
@mkdir -p obj/initfs @mkdir -p obj/initfs
echo test > obj/initfs/test.txt echo test > obj/initfs/test.txt
mkdir -p obj/initfs/dir/dir2 mkdir -p obj/initfs/dir/dir2
ln -s ../test.txt obj/initfs/dir/test2.txt
tar czf obj/initfs.tgz -C obj/initfs . tar czf obj/initfs.tgz -C obj/initfs .
out/disk.iso: obj/kernel.elf obj/initfs.tgz limine out/disk.iso: obj/kernel.elf obj/initfs.tgz limine