Hojun-Cho
fbe0df4e68
temp mirrors Hare's temp: file, named, dir. file() routes through named() and discards the path (no O_TMPFILE yet). Path randomizer uses inline SplitMix64 seeded from getpid + O_EXCL retry (Hare uses crypto::random which we don't ship). named() takes out-pointers for fd + path — return shape gated on tasks #5 and #11. Caller closes and removes; no defer in ww. os gains mkdir, rmdir, flag.EXCL — straight ports of ref/hare/os. selfhost combined files cascade; 995_self_rebuild byte-identity holds.
244 lines
8.7 KiB
Plaintext
244 lines
8.7 KiB
Plaintext
// temp — process-local temporary files and directories.
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//
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// Mirrors Hare's temp:: at ref/hare/temp/+linux.ha; drops underscores
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// per plan 9 style and the layers Hare wires on top of raw os: there
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// is no fs::fs filesystem handle, no io::file abstraction, no defer
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// hook for auto-cleanup. Callers MUST [[os.close]] the returned fd
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// and [[os.remove]] / [[os.rmdir]] the returned path themselves; the
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// absence of defer is a deliberate ergonomic divergence drew-devault
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// was explicit about — do not invent auto-cleanup wrappers.
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//
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// Subset divergence from Hare's +linux.ha:
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//
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// * No TMPDIR env probe. lib/os doesn't expose getenv yet, so
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// [[file]] and [[dir]] are pinned to "/tmp". Graduate to a
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// `gettmpdir` that mirrors Hare's os::tryenv lookup when
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// lib/os.getenv lands.
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// * No O_TMPFILE fast path in [[file]]. We always go through
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// [[named]] and discard the returned path, matching Hare's
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// +freebsd.ha branch (and the +linux.ha fallback). The on-disk
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// entry leaks until the caller of [[named]] removes it; [[file]]
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// callers cannot remove it because they no longer hold the path.
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// Lift to a real O_TMPFILE branch when lib/os gains a TMPFILE
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// flag.
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// * [[named]] writes its (fd, path) result through out-pointers
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// instead of returning Hare's `(io::file, str) | fs::error`
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// 2-tuple. ww's cgen drops 32B return-by-value (task #5) and
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// mis-sizes the (i32, str) tuple (task #11), so we mirror
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// memio's / getopt's out-pointer shape until both close.
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// * Hare's `fs: *fs::fs` parameter is dropped — lib/os hands out
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// raw fds, there is no virtual-filesystem indirection.
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// * `iomode: mode` is our own subset of Hare's io::mode — only
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// WRITE and RDWR, the two values Hare's temp asserts on.
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// * `perm: i32` is the raw Linux mode_t bitset rather than
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// Hare's fs::mode enum; matches what [[os.open]] takes.
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// * No PRNG seeding from crypto::random. Hare reads /dev/urandom
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// (via crypto::random::buffer); ww doesn't ship crypto::random
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// yet, so we seed an inline SplitMix64 from [[os.getpid]] and
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// rely on O_EXCL retry for collision avoidance. Adopt a real
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// entropy source when crypto::random is ported.
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// * The path stored in pathbuf is NUL-terminated for direct
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// handoff to syscalls; the returned str view excludes the NUL.
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// Hare's path::buffer carries no terminator.
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//
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// GRADUATE-IN-ONE-GO WARNING (lib/CLAUDE.md policy). Once tasks #5
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// and #11 close and lib/os exposes a real io::file abstraction plus
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// getenv, [[named]] graduates to Hare's value-returning
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// `(io::file, str) | fs::error` shape with a `fs: *fs::fs` first
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// arg, [[file]] grows an O_TMPFILE fast path, and [[gettmpdir]]
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// consults $TMPDIR. The old out-pointer surface disappears in the
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// same commit — callers MUST NOT bake it into themselves.
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//
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// Caller cleanup template (no defer yet):
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//
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// let fd: i32; let p: str;
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// match (temp.named(&fd, &p, "/tmp", temp.mode.RDWR, 384i32)) {
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// case void => { /* use fd */ os.close(fd); os.remove(p.ptr); };
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// case let e: os.oserror => { /* error */ };
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// };
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//
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// let d: str = temp.dir();
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// /* populate d ... */
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// os.rmdir(d.ptr);
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use os;
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// mode — temp's io flavour. Hare exposes io::mode {READ, WRITE,
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// RDWR}; temp asserts iomode must be WRITE or RDWR, so we ship just
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// those two. Numeric values match the corresponding [[os.flag]]
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// bits so the OR with CREATE/EXCL composes correctly.
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export type mode = enum i32 {
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WRITE = 1, // os.flag.WRONLY
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RDWR = 2, // os.flag.RDWR
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};
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// pathbuf — shared scratch path for [[named]] and [[dir]]. Sized
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// for any caller-supplied directory <= 233 bytes plus our 22-byte
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// "/temp.<16-hex-digits>\0" suffix; [[named]] returns ENAMETOOLONG
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// past that. Hare uses a path::buffer of PATH_MAX bytes; this
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// collapses to a single static slot because lib/path doesn't yet
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// ship a path::buffer type. NUL byte at `pathbuf[pathlen]` lets the
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// bytes be handed straight to [[os.open]] / [[os.mkdir]] /
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// [[os.remove]] / [[os.rmdir]].
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let pathbuf: [256]u8;
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let pathlen: i32 = 0;
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// rng* — SplitMix64 state. Lazily seeded on first call from
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// [[os.getpid]]; collisions are caught by the O_EXCL retry loops in
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// [[named]] and [[dir]]. Inline rather than `use math.random;` to
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// keep temp's import surface minimal and avoid pulling random's
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// module-level scope into temp's namespace.
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let rngstate: u64 = 0u64;
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let rnginit: i32 = 0;
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fn seedrng() void = {
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if (rnginit == 0) {
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rngstate = (os.getpid(): u64) ^ 0x9E3779B97F4A7C15u64;
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rnginit = 1;
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};
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};
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fn nextrand() u64 = {
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seedrng();
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rngstate = rngstate + 0x9E3779B97F4A7C15u64;
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let a: u64 = rngstate;
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a = (a ^ (a >> 30u64)) * 0xBF58476D1CE4E5B9u64;
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a = (a ^ (a >> 27u64)) * 0x94D049BB133111EBu64;
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return a ^ (a >> 31u64);
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};
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// gettmpdir — Hare's get_tmpdir(). Hardcoded /tmp until lib/os
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// exposes getenv; documented in the file header.
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fn gettmpdir() str = { return "/tmp"; };
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// puts — copy `s` into pathbuf starting at `off`. Caps writes
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// against pathbuf's capacity so a long caller-supplied dir can't
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// run off the end. Returns the new offset.
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fn puts(off: i32, s: str) i32 = {
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let i: i32 = 0;
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for (i < s.len) {
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if (off + i >= 255) { break; };
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pathbuf[off + i] = s[i];
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i += 1;
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};
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return off + i;
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};
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// puthex — 16 lowercase hex digits of `v` into pathbuf[off..off+16].
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fn puthex(off: i32, v: u64) i32 = {
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let hex: str = "0123456789abcdef";
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let i: i32 = 0;
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for (i < 16) {
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let shift: u64 = ((15 - i): u64) * 4u64;
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let nib: i32 = ((v >> shift) & 0xFu64): i32;
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if (off + i < 255) { pathbuf[off + i] = hex[nib]; };
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i += 1;
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};
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return off + 16;
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};
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// makenamed — `<dir>/temp.<hex>\0` into pathbuf. Returns the path
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// length (excluding NUL).
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fn makenamed(dir: str) i32 = {
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let off: i32 = 0;
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off = puts(off, dir);
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pathbuf[off] = 47u8; off += 1; // '/'
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off = puts(off, "temp.");
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off = puthex(off, nextrand());
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pathbuf[off] = 0u8;
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return off;
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};
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// makedir — `<tmpdir>/<hex>\0` into pathbuf. Returns path length
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// (excluding NUL).
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fn makedir() i32 = {
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let off: i32 = 0;
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off = puts(off, gettmpdir());
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pathbuf[off] = 47u8; off += 1;
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off = puthex(off, nextrand());
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pathbuf[off] = 0u8;
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return off;
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};
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@symbol("rt_abort") fn rtabort(msg: str) void;
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// named — create a fresh `<dir>/temp.<hex>` with O_EXCL. On success
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// `*outfd` receives the fd and `*outpath` receives a borrowed view
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// into a module-level path buffer; the buffer is overwritten on
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// every subsequent [[named]] or [[dir]] call. Caller MUST close
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// *outfd and [[os.remove]] *outpath when done.
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//
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// Returns -ENAMETOOLONG (-36) as `os.oserror` if `dir.len > 233`:
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// pathbuf is 256B, the suffix "/temp.<16-hex>\0" needs 22 bytes,
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// leaving 234 for `dir` (0..233 inclusive). Without this guard
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// [[makenamed]]'s final NUL-store would write past pathbuf's end.
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//
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// Mirrors Hare's temp::named (minus the fs::fs first arg and the
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// 2-tuple return — see file header).
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export fn named(outfd: *i32, outpath: *str,
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dir: str, iomode: mode, perm: i32) (void | os.oserror) = {
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if (dir.len > 233) { return -36i64: os.oserror; };
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let flags: os.flag = os.flag.CREATE | os.flag.EXCL;
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if (iomode == mode.RDWR) {
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flags = flags | os.flag.RDWR;
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} else {
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flags = flags | os.flag.WRONLY;
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};
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for (true) {
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pathlen = makenamed(dir);
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let fd: i32 = os.open(&pathbuf[0], flags, perm);
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if (fd >= 0) {
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*outfd = fd;
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let p: str;
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p.ptr = &pathbuf[0];
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p.len = pathlen;
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*outpath = p;
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return;
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};
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let e: i64 = fd: i64;
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if (e != -17i64) { return e: os.oserror; }; // -EEXIST → retry
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};
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return;
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};
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// file — create a temporary file under [[gettmpdir]] and return the
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// fd. The on-disk path is discarded; without O_TMPFILE the entry
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// persists until removed externally. Matches Hare's +freebsd.ha
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// branch (and the +linux.ha fallback path). Caller MUST close.
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//
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// Mirrors Hare's temp::file.
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export fn file(iomode: mode, perm: i32) (i32 | os.oserror) = {
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let fd: i32 = 0;
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let p: str;
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match (named(&fd, &p, gettmpdir(), iomode, perm)) {
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case void => return fd;
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case let e: os.oserror => return e;
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};
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};
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// dir — create a fresh temporary directory under [[gettmpdir]] with
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// mode 0o700. Returns a borrowed view of the static path buffer;
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// the buffer is overwritten on every subsequent [[named]] or
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// [[dir]] call. Caller MUST [[os.rmdir]] the path when done.
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// Aborts on syscall failure other than EEXIST, mirroring Hare's
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// `abort("Could not create temp directory")`.
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//
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// Mirrors Hare's temp::dir.
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export fn dir() str = {
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for (true) {
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pathlen = makedir();
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let r: i32 = os.mkdir(&pathbuf[0], 448i32); // 0o700
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if (r >= 0) {
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let p: str;
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p.ptr = &pathbuf[0];
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p.len = pathlen;
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return p;
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};
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if (r != -17) { rtabort("temp.dir: mkdir failed"); }; // EEXIST → retry
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};
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let p: str;
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p.ptr = &pathbuf[0];
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p.len = pathlen;
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return p;
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};
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