Files
Odin/core/os/os2/file_linux.odin
2025-08-08 12:38:20 +01:00

565 lines
15 KiB
Odin

#+private
package os2
import "base:runtime"
import "core:io"
import "core:time"
import "core:sync"
import "core:sys/linux"
// Most implementations will EINVAL at some point when doing big writes.
// In practice a read/write call would probably never read/write these big buffers all at once,
// which is why the number of bytes is returned and why there are procs that will call this in a
// loop for you.
// We set a max of 1GB to keep alignment and to be safe.
MAX_RW :: 1 << 30
File_Impl :: struct {
file: File,
name: string,
fd: linux.Fd,
allocator: runtime.Allocator,
buffer: []byte,
rw_mutex: sync.RW_Mutex, // read write calls
p_mutex: sync.Mutex, // pread pwrite calls
}
_stdin := File{
stream = {
procedure = _file_stream_proc,
},
fstat = _fstat,
}
_stdout := File{
stream = {
procedure = _file_stream_proc,
},
fstat = _fstat,
}
_stderr := File{
stream = {
procedure = _file_stream_proc,
},
fstat = _fstat,
}
@init
_standard_stream_init :: proc "contextless" () {
new_std :: proc "contextless" (impl: ^File_Impl, fd: linux.Fd, name: string) -> ^File {
impl.file.impl = impl
impl.fd = linux.Fd(fd)
impl.allocator = runtime.nil_allocator()
impl.name = name
impl.file.stream = {
data = impl,
procedure = _file_stream_proc,
}
impl.file.fstat = _fstat
return &impl.file
}
@(static) files: [3]File_Impl
stdin = new_std(&files[0], 0, "/proc/self/fd/0")
stdout = new_std(&files[1], 1, "/proc/self/fd/1")
stderr = new_std(&files[2], 2, "/proc/self/fd/2")
}
_open :: proc(name: string, flags: File_Flags, perm: int) -> (f: ^File, err: Error) {
temp_allocator := TEMP_ALLOCATOR_GUARD({})
name_cstr := clone_to_cstring(name, temp_allocator) or_return
// Just default to using O_NOCTTY because needing to open a controlling
// terminal would be incredibly rare. This has no effect on files while
// allowing us to open serial devices.
sys_flags: linux.Open_Flags = {.NOCTTY, .CLOEXEC}
when size_of(rawptr) == 4 {
sys_flags += {.LARGEFILE}
}
switch flags & (O_RDONLY|O_WRONLY|O_RDWR) {
case O_RDONLY:
case O_WRONLY: sys_flags += {.WRONLY}
case O_RDWR: sys_flags += {.RDWR}
}
if .Append in flags { sys_flags += {.APPEND} }
if .Create in flags { sys_flags += {.CREAT} }
if .Excl in flags { sys_flags += {.EXCL} }
if .Sync in flags { sys_flags += {.DSYNC} }
if .Trunc in flags { sys_flags += {.TRUNC} }
if .Inheritable in flags { sys_flags -= {.CLOEXEC} }
fd, errno := linux.open(name_cstr, sys_flags, transmute(linux.Mode)u32(perm))
if errno != .NONE {
return nil, _get_platform_error(errno)
}
return _new_file(uintptr(fd), name, file_allocator())
}
_new_file :: proc(fd: uintptr, _: string, allocator: runtime.Allocator) -> (f: ^File, err: Error) {
impl := new(File_Impl, allocator) or_return
defer if err != nil {
free(impl, allocator)
}
impl.file.impl = impl
impl.fd = linux.Fd(fd)
impl.allocator = allocator
impl.name = _get_full_path(impl.fd, impl.allocator) or_return
impl.file.stream = {
data = impl,
procedure = _file_stream_proc,
}
impl.file.fstat = _fstat
return &impl.file, nil
}
_clone :: proc(f: ^File) -> (clone: ^File, err: Error) {
if f == nil || f.impl == nil {
return
}
fd := (^File_Impl)(f.impl).fd
clonefd, errno := linux.dup(fd)
if errno != nil {
err = _get_platform_error(errno)
return
}
defer if err != nil { linux.close(clonefd) }
return _new_file(uintptr(clonefd), "", file_allocator())
}
@(require_results)
_open_buffered :: proc(name: string, buffer_size: uint, flags := File_Flags{.Read}, perm := 0o777) -> (f: ^File, err: Error) {
assert(buffer_size > 0)
f, err = _open(name, flags, perm)
if f != nil && err == nil {
impl := (^File_Impl)(f.impl)
impl.buffer = make([]byte, buffer_size, file_allocator())
f.stream.procedure = _file_stream_buffered_proc
}
return
}
_destroy :: proc(f: ^File_Impl) -> Error {
if f == nil {
return nil
}
a := f.allocator
err0 := delete(f.name, a)
err1 := delete(f.buffer, a)
err2 := free(f, a)
err0 or_return
err1 or_return
err2 or_return
return nil
}
_close :: proc(f: ^File_Impl) -> Error {
if f == nil{
return nil
}
errno := linux.close(f.fd)
if errno == .EBADF { // avoid possible double free
return _get_platform_error(errno)
}
_destroy(f)
return _get_platform_error(errno)
}
_fd :: proc(f: ^File) -> uintptr {
if f == nil || f.impl == nil {
return ~uintptr(0)
}
impl := (^File_Impl)(f.impl)
return uintptr(impl.fd)
}
_name :: proc(f: ^File) -> string {
return (^File_Impl)(f.impl).name if f != nil && f.impl != nil else ""
}
_seek :: proc(f: ^File_Impl, offset: i64, whence: io.Seek_From) -> (ret: i64, err: Error) {
// We have to handle this here, because Linux returns EINVAL for both
// invalid offsets and invalid whences.
switch whence {
case .Start, .Current, .End:
break
case:
return 0, .Invalid_Whence
}
n, errno := linux.lseek(f.fd, offset, linux.Seek_Whence(whence))
#partial switch errno {
case .EINVAL:
return 0, .Invalid_Offset
case .NONE:
return n, nil
case:
return -1, _get_platform_error(errno)
}
}
_read :: proc(f: ^File_Impl, p: []byte) -> (i64, Error) {
if len(p) <= 0 {
return 0, nil
}
n, errno := linux.read(f.fd, p[:min(len(p), MAX_RW)])
if errno != .NONE {
return -1, _get_platform_error(errno)
}
return i64(n), io.Error.EOF if n == 0 else nil
}
_read_at :: proc(f: ^File_Impl, p: []byte, offset: i64) -> (i64, Error) {
if len(p) <= 0 {
return 0, nil
}
if offset < 0 {
return 0, .Invalid_Offset
}
n, errno := linux.pread(f.fd, p[:min(len(p), MAX_RW)], offset)
if errno != .NONE {
return -1, _get_platform_error(errno)
}
if n == 0 {
return 0, .EOF
}
return i64(n), nil
}
_write :: proc(f: ^File_Impl, p: []byte) -> (nt: i64, err: Error) {
p := p
for len(p) > 0 {
n, errno := linux.write(f.fd, p[:min(len(p), MAX_RW)])
if errno != .NONE {
err = _get_platform_error(errno)
return
}
p = p[n:]
nt += i64(n)
}
return
}
_write_at :: proc(f: ^File_Impl, p: []byte, offset: i64) -> (nt: i64, err: Error) {
if offset < 0 {
return 0, .Invalid_Offset
}
p := p
offset := offset
for len(p) > 0 {
n, errno := linux.pwrite(f.fd, p[:min(len(p), MAX_RW)], offset)
if errno != .NONE {
err = _get_platform_error(errno)
return
}
p = p[n:]
nt += i64(n)
offset += i64(n)
}
return
}
@(no_sanitize_memory)
_file_size :: proc(f: ^File_Impl) -> (n: i64, err: Error) {
// TODO: Identify 0-sized "pseudo" files and return No_Size. This would
// eliminate the need for the _read_entire_pseudo_file procs.
s: linux.Stat = ---
errno := linux.fstat(f.fd, &s)
if errno != .NONE {
return -1, _get_platform_error(errno)
}
if s.mode & linux.S_IFMT == linux.S_IFREG {
return i64(s.size), nil
}
return 0, .No_Size
}
_sync :: proc(f: ^File) -> Error {
impl := (^File_Impl)(f.impl)
return _get_platform_error(linux.fsync(impl.fd))
}
_flush :: proc(f: ^File_Impl) -> Error {
return _get_platform_error(linux.fsync(f.fd))
}
_truncate :: proc(f: ^File, size: i64) -> Error {
impl := (^File_Impl)(f.impl)
return _get_platform_error(linux.ftruncate(impl.fd, size))
}
_remove :: proc(name: string) -> Error {
temp_allocator := TEMP_ALLOCATOR_GUARD({})
name_cstr := clone_to_cstring(name, temp_allocator) or_return
if fd, errno := linux.open(name_cstr, _OPENDIR_FLAGS + {.NOFOLLOW}); errno == .NONE {
linux.close(fd)
return _get_platform_error(linux.rmdir(name_cstr))
}
return _get_platform_error(linux.unlink(name_cstr))
}
_rename :: proc(old_name, new_name: string) -> Error {
temp_allocator := TEMP_ALLOCATOR_GUARD({})
old_name_cstr := clone_to_cstring(old_name, temp_allocator) or_return
new_name_cstr := clone_to_cstring(new_name, temp_allocator) or_return
return _get_platform_error(linux.rename(old_name_cstr, new_name_cstr))
}
_link :: proc(old_name, new_name: string) -> Error {
temp_allocator := TEMP_ALLOCATOR_GUARD({})
old_name_cstr := clone_to_cstring(old_name, temp_allocator) or_return
new_name_cstr := clone_to_cstring(new_name, temp_allocator) or_return
return _get_platform_error(linux.link(old_name_cstr, new_name_cstr))
}
_symlink :: proc(old_name, new_name: string) -> Error {
temp_allocator := TEMP_ALLOCATOR_GUARD({})
old_name_cstr := clone_to_cstring(old_name, temp_allocator) or_return
new_name_cstr := clone_to_cstring(new_name, temp_allocator) or_return
return _get_platform_error(linux.symlink(old_name_cstr, new_name_cstr))
}
_read_link_cstr :: proc(name_cstr: cstring, allocator: runtime.Allocator) -> (string, Error) {
bufsz : uint = 256
buf := make([]byte, bufsz, allocator)
for {
sz, errno := linux.readlink(name_cstr, buf[:])
if errno != .NONE {
delete(buf, allocator)
return "", _get_platform_error(errno)
} else if sz == int(bufsz) {
bufsz *= 2
delete(buf, allocator)
buf = make([]byte, bufsz, allocator)
} else {
return string(buf[:sz]), nil
}
}
}
_read_link :: proc(name: string, allocator: runtime.Allocator) -> (s: string, e: Error) {
temp_allocator := TEMP_ALLOCATOR_GUARD({ allocator })
name_cstr := clone_to_cstring(name, temp_allocator) or_return
return _read_link_cstr(name_cstr, allocator)
}
_chdir :: proc(name: string) -> Error {
temp_allocator := TEMP_ALLOCATOR_GUARD({})
name_cstr := clone_to_cstring(name, temp_allocator) or_return
return _get_platform_error(linux.chdir(name_cstr))
}
_fchdir :: proc(f: ^File) -> Error {
impl := (^File_Impl)(f.impl)
return _get_platform_error(linux.fchdir(impl.fd))
}
_chmod :: proc(name: string, mode: int) -> Error {
temp_allocator := TEMP_ALLOCATOR_GUARD({})
name_cstr := clone_to_cstring(name, temp_allocator) or_return
return _get_platform_error(linux.chmod(name_cstr, transmute(linux.Mode)(u32(mode))))
}
_fchmod :: proc(f: ^File, mode: int) -> Error {
impl := (^File_Impl)(f.impl)
return _get_platform_error(linux.fchmod(impl.fd, transmute(linux.Mode)(u32(mode))))
}
// NOTE: will throw error without super user priviledges
_chown :: proc(name: string, uid, gid: int) -> Error {
temp_allocator := TEMP_ALLOCATOR_GUARD({})
name_cstr := clone_to_cstring(name, temp_allocator) or_return
return _get_platform_error(linux.chown(name_cstr, linux.Uid(uid), linux.Gid(gid)))
}
// NOTE: will throw error without super user priviledges
_lchown :: proc(name: string, uid, gid: int) -> Error {
temp_allocator := TEMP_ALLOCATOR_GUARD({})
name_cstr := clone_to_cstring(name, temp_allocator) or_return
return _get_platform_error(linux.lchown(name_cstr, linux.Uid(uid), linux.Gid(gid)))
}
// NOTE: will throw error without super user priviledges
_fchown :: proc(f: ^File, uid, gid: int) -> Error {
impl := (^File_Impl)(f.impl)
return _get_platform_error(linux.fchown(impl.fd, linux.Uid(uid), linux.Gid(gid)))
}
_chtimes :: proc(name: string, atime, mtime: time.Time) -> Error {
temp_allocator := TEMP_ALLOCATOR_GUARD({})
name_cstr := clone_to_cstring(name, temp_allocator) or_return
times := [2]linux.Time_Spec {
{
uint(atime._nsec) / uint(time.Second),
uint(atime._nsec) % uint(time.Second),
},
{
uint(mtime._nsec) / uint(time.Second),
uint(mtime._nsec) % uint(time.Second),
},
}
return _get_platform_error(linux.utimensat(linux.AT_FDCWD, name_cstr, &times[0], nil))
}
_fchtimes :: proc(f: ^File, atime, mtime: time.Time) -> Error {
times := [2]linux.Time_Spec {
{
uint(atime._nsec) / uint(time.Second),
uint(atime._nsec) % uint(time.Second),
},
{
uint(mtime._nsec) / uint(time.Second),
uint(mtime._nsec) % uint(time.Second),
},
}
impl := (^File_Impl)(f.impl)
return _get_platform_error(linux.utimensat(impl.fd, nil, &times[0], nil))
}
_exists :: proc(name: string) -> bool {
temp_allocator := TEMP_ALLOCATOR_GUARD({})
name_cstr, _ := clone_to_cstring(name, temp_allocator)
return linux.access(name_cstr, linux.F_OK) == .NONE
}
/* For reading Linux system files that stat to size 0 */
_read_entire_pseudo_file :: proc { _read_entire_pseudo_file_string, _read_entire_pseudo_file_cstring }
_read_entire_pseudo_file_string :: proc(name: string, allocator: runtime.Allocator) -> (b: []u8, e: Error) {
temp_allocator := TEMP_ALLOCATOR_GUARD({ allocator })
name_cstr := clone_to_cstring(name, temp_allocator) or_return
return _read_entire_pseudo_file_cstring(name_cstr, allocator)
}
_read_entire_pseudo_file_cstring :: proc(name: cstring, allocator: runtime.Allocator) -> ([]u8, Error) {
fd, errno := linux.open(name, {})
if errno != .NONE {
return nil, _get_platform_error(errno)
}
defer linux.close(fd)
BUF_SIZE_STEP :: 128
contents := make([dynamic]u8, 0, BUF_SIZE_STEP, allocator)
n: int
i: int
for {
resize(&contents, i + BUF_SIZE_STEP)
n, errno = linux.read(fd, contents[i:i+BUF_SIZE_STEP])
if errno != .NONE {
delete(contents)
return nil, _get_platform_error(errno)
}
if n < BUF_SIZE_STEP {
break
}
i += BUF_SIZE_STEP
}
resize(&contents, i + n)
return contents[:], nil
}
@(private="package")
_file_stream_proc :: proc(stream_data: rawptr, mode: io.Stream_Mode, p: []byte, offset: i64, whence: io.Seek_From) -> (n: i64, err: io.Error) {
f := (^File_Impl)(stream_data)
ferr: Error
switch mode {
case .Read:
n, ferr = _read(f, p)
err = error_to_io_error(ferr)
return
case .Read_At:
n, ferr = _read_at(f, p, offset)
err = error_to_io_error(ferr)
return
case .Write:
n, ferr = _write(f, p)
err = error_to_io_error(ferr)
return
case .Write_At:
n, ferr = _write_at(f, p, offset)
err = error_to_io_error(ferr)
return
case .Seek:
n, ferr = _seek(f, offset, whence)
err = error_to_io_error(ferr)
return
case .Size:
n, ferr = _file_size(f)
err = error_to_io_error(ferr)
return
case .Flush:
ferr = _flush(f)
err = error_to_io_error(ferr)
return
case .Close, .Destroy:
ferr = _close(f)
err = error_to_io_error(ferr)
return
case .Query:
return io.query_utility({.Read, .Read_At, .Write, .Write_At, .Seek, .Size, .Flush, .Close, .Destroy, .Query})
}
return 0, .Empty
}
@(private="package")
_file_stream_buffered_proc :: proc(stream_data: rawptr, mode: io.Stream_Mode, p: []byte, offset: i64, whence: io.Seek_From) -> (n: i64, err: io.Error) {
f := (^File_Impl)(stream_data)
ferr: Error
switch mode {
case .Read:
n, ferr = _read(f, p)
err = error_to_io_error(ferr)
return
case .Read_At:
n, ferr = _read_at(f, p, offset)
err = error_to_io_error(ferr)
return
case .Write:
n, ferr = _write(f, p)
err = error_to_io_error(ferr)
return
case .Write_At:
n, ferr = _write_at(f, p, offset)
err = error_to_io_error(ferr)
return
case .Seek:
n, ferr = _seek(f, offset, whence)
err = error_to_io_error(ferr)
return
case .Size:
n, ferr = _file_size(f)
err = error_to_io_error(ferr)
return
case .Flush:
ferr = _flush(f)
err = error_to_io_error(ferr)
return
case .Close, .Destroy:
ferr = _close(f)
err = error_to_io_error(ferr)
return
case .Query:
return io.query_utility({.Read, .Read_At, .Write, .Write_At, .Seek, .Size, .Flush, .Close, .Destroy, .Query})
}
return 0, .Empty
}