Files
danos/library/posix/stdio.zig
T
Daniel Samson ceacc6b514 Post-reorg cleanup: POSIX layer, and naming fixes
Follow-up to the monorepo re-org. Suite 35/35 plus host tests green.

POSIX compatibility is now its own library, library/posix/ (unistd, stdio),
layered strictly over the runtime — it calls the runtime's IPC/heap, never
system calls directly. The runtime is now POSIX-free (the danos-native
application ABI). The VFS wire protocol is danos-native throughout
(Stat -> FileStatus, .stat -> .status, O_CREAT -> create); the POSIX layer
maps the POSIX spellings at the boundary. The coding standard's ABI-name
exception is scoped to one place: a file is allowed POSIX spellings only if it
lives under library/posix/ — everywhere else, danos naming with no exception.

Naming fixes, all mechanical:
- initrd -> initial-ramdisk: the source file, the module, the tool
  (make-initial-ramdisk.py), the artifact (initial-ramdisk.img, including the
  bootloader's load path), and the identifiers.
- system/kernel/device-service.zig -> devices-broker.zig: it is ring-0 kernel
  code (the trusted device table + claim capability), not a ring-3 service. The
  future user-space device *manager* (policy) will live in system/services/.
- Dropped the daemon `d` suffix: hpetd -> hpet, busd -> bus. A driver lives in
  system/drivers/, so the folder already says what it is; encoding the role in
  the name too is redundant. The coding standard drops that exception.
- system/devices/aml/interp.zig -> interpreter.zig (the type was already
  Interpreter).
2026-07-10 13:33:06 +01:00

116 lines
3.2 KiB
Zig

//! A small C stdio layer over the POSIX-style file API (unistd.zig). Unbuffered
//! for now — each fread/fwrite is one VFS round trip; an internal buffer (fewer
//! IPC calls) is a later optimisation. Both a Zig-callable API and `extern "C"`
//! symbols are provided, so Zig and future C programs share it.
const std = @import("std");
const unistd = @import("unistd.zig");
const heap = @import("runtime").heap;
pub const SEEK_SET = unistd.SEEK_SET;
pub const SEEK_CURRENT = unistd.SEEK_CURRENT;
pub const SEEK_END = unistd.SEEK_END;
/// A C `FILE`: an fd plus sticky end-of-file / error flags. Allocated on the
/// heap; `fclose` frees it.
pub const FILE = extern struct {
fd: i32,
eof: c_int = 0,
err: c_int = 0,
};
fn flagsFor(mode: []const u8) u32 {
if (mode.len == 0) return 0;
return switch (mode[0]) {
'w', 'a' => unistd.O_CREAT,
else => 0,
};
}
/// Open `path` in `mode` ("r"/"w"/"a", '+' ignored for now). Returns null on error.
pub fn fopen(path: []const u8, mode: []const u8) ?*FILE {
const fd = unistd.open(path, flagsFor(mode));
if (fd < 0) return null;
const f = heap.allocator().create(FILE) catch {
unistd.close(fd);
return null;
};
f.* = .{ .fd = fd };
if (mode.len > 0 and mode[0] == 'a') _ = unistd.lseek(fd, 0, unistd.SEEK_END);
return f;
}
pub fn fclose(f: *FILE) c_int {
unistd.close(f.fd);
heap.allocator().destroy(f);
return 0;
}
/// Read `size*nmemb` bytes; returns the number of whole items read.
pub fn fread(buffer: []u8, size: usize, nmemb: usize, f: *FILE) usize {
const total = size * nmemb;
if (total == 0) return 0;
const n = unistd.read(f.fd, buffer[0..@min(buffer.len, total)]);
if (n <= 0) {
f.eof = 1;
return 0;
}
return @as(usize, @intCast(n)) / size;
}
/// Write `size*nmemb` bytes; returns the number of whole items written.
pub fn fwrite(data: []const u8, size: usize, nmemb: usize, f: *FILE) usize {
const total = @min(data.len, size * nmemb);
if (total == 0) return 0;
const n = unistd.write(f.fd, data[0..total]);
if (n <= 0) {
f.err = 1;
return 0;
}
return @as(usize, @intCast(n)) / size;
}
pub fn fseek(f: *FILE, off: i64, whence: u32) c_int {
f.eof = 0;
return if (unistd.lseek(f.fd, off, whence) < 0) -1 else 0;
}
pub fn ftell(f: *FILE) i64 {
return unistd.lseek(f.fd, 0, unistd.SEEK_CURRENT);
}
pub fn rewind(f: *FILE) void {
_ = fseek(f, 0, SEEK_SET);
}
pub fn feof(f: *FILE) c_int {
return f.eof;
}
pub fn ferror(f: *FILE) c_int {
return f.err;
}
pub fn fputs(s: []const u8, f: *FILE) c_int {
return if (unistd.write(f.fd, s) < 0) -1 else 0;
}
pub fn fputc(c: u8, f: *FILE) c_int {
const b = [_]u8{c};
return if (unistd.write(f.fd, &b) == 1) c else -1;
}
pub fn fgetc(f: *FILE) c_int {
var b: [1]u8 = undefined;
const n = unistd.read(f.fd, &b);
if (n <= 0) {
f.eof = 1;
return -1; // EOF
}
return b[0];
}
// Real `extern "C"` symbols (fopen/fread/fseek/...) — with a C-string signature
// distinct from the Zig slice API above — land with the first C program, wired
// via @export so they don't collide with these Zig names.