stuffr_cli/compat/unzip/

mod.rs

//! The unzip family (`unzip`, `zipinfo`, `funzip`): stuffr behaving as the
//! platform's Info-ZIP UnZip 6.00.
//!
//! **A port** of Apple's `zip-33` tree (`unzip/unzip60/`, the Info-ZIP
//! licence version 2009-Jan-02, `LICENSE-infozip`; this is an altered
//! version, marked as such by every banner). Each ported function carries
//! `// port: <file>.c:<function>`, each Apple change `// apple:
//! <file>.c:<line>`, each Ubuntu difference `// ubuntu: <patch>` or `//
//! ubuntu: -D<DEFINE>`, and each rule taken from the binary rather than the
//! source `// probe: <command>`; where the two disagree, the binary wins.
//! Every string is in `messages.rs`.
//!
//! **Flavours** ([`Flavour`], `flavour.rs`): Apple's `/usr/bin/unzip` on
//! macOS and the BSDs, Ubuntu 24.04's `6.0-28ubuntu4.1` elsewhere
//! ([`default_flavour`]), or as `STUFFR_UNZIP_FLAVOR` (`apple`, `ubuntu`)
//! says; [`run`] reads it once, and anything else in it is refused, exit 1,
//! in stuffr's own words. Ubuntu's build options (its `-D` DEFINES) and
//! its patch series are flavour checks at the points they change
//! behaviour (R13), each marked `// ubuntu:`.
//!
//! **G becomes `Uz`** (R5): Info-ZIP's global `G` (and its `uO`
//! options) is one value per run, holding the host, the flavour, the
//! options and the state, so a sandboxed run ([`run_in_counted`]) touches
//! nothing of the process.
//!
//! **What is here:** the names, the flavour, the
//! command line (`unzip.c`'s `unzip()` front half and `uz_opts()`,
//! `zipinfo.c`'s `zi_opts()`, `envargs.c`), the usage screens, `-hh`, the
//! `-v` screen and funzip's usage (Task 7); opening archives, wildcard
//! archive names, the end records, Zip64, the central directory walk,
//! wildcards and unzip's listings `-l`, `-v`, `-z`, `-T` (`process.rs`,
//! `unix/mod.rs`, `matching.rs`, `list.rs`, `fileio.rs`: Task 8); zipinfo's
//! listings, every format, the totals and the `-v` report (`zipinfo/`:
//! Task 9); testing and extraction (`extract/`: `extract.c`, `fileio.c`'s
//! output side, crypt.c's `decrypt()`; `unix/mapname.rs`, `unix/attrs.rs`:
//! `unix.c`'s names, paths, modes, times and symlinks; `unix/beneath.rs`:
//! the resolve-beneath walk every change goes through; Task 10); the
//! terminal (`ttyio.rs`: `getp()` on `/dev/tty`, `zgetch()`,
//! `screensize()`; `fileio.rs`: `UzpPassword()`, `UzpMorePause()`; `-M`'s
//! line counting in `Uz::print_raw`; crypt.c's retries; the interrupt
//! handler, exit 80: Task 11); funzip (`funzip.rs`: funzip.c, Task 12);
//! Ubuntu's build options and patch series as flavour checks throughout
//! (Tasks 13 and 14; `process/unicode.rs` is Ubuntu's alone).

//! Known deviations (the source of truth; the README and the spec mirror
//! this list):
//!
//! 1. SIGPIPE: `run` restores SIGPIPE's default action, as the other
//!    families do; under a parent that ignores SIGPIPE, unzip sees `EPIPE`
//!    and stuffr still dies of the signal (the Rust runtime ignores it
//!    before `main`, so the inherited disposition cannot be told apart).
//! 2. The first banner line of each program's usage and `-v` names stuffr
//!    and says it is altered (Info-ZIP licence clause 3):
//!    `UnZip 6.00 of 20 April 2009, by stuffr X.Y.Z (altered; original by
//!    Info-ZIP, with modifications by Apple Inc.).` (Ubuntu: `(altered;
//!    Debian's build, original by Info-ZIP).`), and likewise for zipinfo
//!    and funzip. That line is wider than the pager's 80 columns, so under
//!    `-M` it counts as two screen lines and `-Mh` pauses one text line
//!    earlier than the reference (P26). `-v`'s `Compiled with` line is the
//!    recorded reference build's (Apple: this release's macOS build), so
//!    other macOS builds print a different one.
//! 3. Pre-existing symlinks: the Ubuntu flavour also stays beneath the
//!    extraction root, as Apple's does. On unix only: off unix (Windows)
//!    the walk (`unix/beneath.rs`'s `imp_std`) follows symlinks, so
//!    neither flavour is contained there.
//! 4. The archive being read is never overwritten.
//! 5. `-O`/`-I` (Ubuntu) convert names through `iconv(3)`; they are
//!    unavailable on Windows, where they are parsed as Ubuntu parses them
//!    and convert nothing, as a conversion Ubuntu's `iconv_open()` refuses
//!    (silently: the names stay as stored; ruling T14-5).
//! 6. Locale-dependent output is identical under `C`, `C.UTF-8` and
//!    `en_US.UTF-8` only.
//! 7. On macOS the Ubuntu flavour also propagates the archive's quarantine
//!    attribute (R9), as Apple's does.
//! 8. The terminal (T11-1, P28): after a prompt, a pager key or an
//!    interrupt, the terminal's mode is put back exactly as it was, where
//!    unzip's `echon()` only sets echo again (after an interrupt in the
//!    `-M` pager it leaves canonical mode off). A SIGABRT stuffr raises
//!    itself (a crash) kills it by the signal; one sent by another process
//!    exits 80, as unzip does for both. funzip installs no handler, so a
//!    signal at its password prompt kills it, echo off; stuffr puts the
//!    mode back first, then dies of the same signal (`host::arm_tty_restore`).
//! 9. funzip never loses a write failure (T12-4): a failed write to
//!    standard output is answered `out of space on stdout`, exit 9, on a
//!    real host too. The C writes through buffered stdio and does not check
//!    its final `fflush()`, so it loses the data and exits 0.
//! 10. Undefined behaviour and endless loops are not reproduced. Where a
//!     reference's behaviour is undefined, or never ends, stuffr gives a
//!     defined answer instead. Ubuntu's bzip2 decoding loops for ever on a
//!     truncated entry; stuffr answers as for bad bzip2 data, exit 2
//!     (T13-2). Apple's `-:` on a `../` directory entry changes the
//!     directory above the extraction root; stuffr refuses (T10-10). After
//!     a failed create Apple writes through the previous entry's closed
//!     stream; stuffr says "cannot create" and goes on (T10-11). At the end
//!     of input the C asks for a new name for ever at the rename prompt,
//!     and waits for ever at the `-M` pager's; stuffr takes `[N]one` and
//!     stops pausing (T10-9, T11-4). Buffer overflows are answered in both
//!     flavours with the forms of Ubuntu's CVE fixes: a method above 999
//!     is `Unk` and four hex digits (`Unk03E8`), and a password prompt
//!     whose names are too long is "Enter password: " (T11-5). The full
//!     set is in the code's `// ruling:` comments.

use std::collections::BTreeMap;
use std::ffi::{OsStr, OsString};
use std::io::{self, BufWriter, Write};
use std::path::Path;
use std::process::ExitCode;
use std::sync::atomic::AtomicU64;
use std::sync::{Arc, Mutex};

use super::CountedRun;
use super::host::{self, Host, SANDBOX_OUTPUT_CAP, Sandbox};

pub(crate) mod cli;
mod extract;
mod fileio;
pub(crate) mod flavour;
mod funzip;
mod list;
mod matching;
mod messages;
mod process;
mod ttyio;
mod unix;
mod zipinfo;

pub use flavour::Flavour;
use messages::{self as m, printf};

/// The environment variable that overrides [`default_flavour`].
const FLAVOR_VAR: &str = "STUFFR_UNZIP_FLAVOR";

// unzip.h's PK_* exit codes (those the front end returns).
/// unzip.h:PK_OK, no error.
pub(crate) const PK_OK: i32 = 0;
/// unzip.h:PK_COOL, no error (the usage screen was asked for).
pub(crate) const PK_COOL: i32 = 0;
/// unzip.h:PK_WARN, a warning.
pub(crate) const PK_WARN: i32 = 1;
/// unzip.h:PK_ERR, an error in the archive.
pub(crate) const PK_ERR: i32 = 2;
/// unzip.h:PK_BADERR, a severe error.
pub(crate) const PK_BADERR: i32 = 3;
/// unzip.h:PK_NOZIP, the archive was not found.
pub(crate) const PK_NOZIP: i32 = 9;
/// unzip.h:PK_PARAM, bad or illegal parameters.
pub(crate) const PK_PARAM: i32 = 10;
/// unzip.h:PK_FIND, no files found.
pub(crate) const PK_FIND: i32 = 11;
/// unzip.h:PK_EOF, an unexpected end of the archive.
pub(crate) const PK_EOF: i32 = 51;
/// unzip.h:IZ_CTRLC, "user hit ^C to terminate": the interrupt's exit code.
pub(crate) const IZ_CTRLC: i32 = 80;
/// unzpriv.h:IZ_DIR, the archive operand is a directory (never an exit
/// code: `process_zipfiles()` counts it).
pub(crate) const IZ_DIR: i32 = 76;

// unzpriv.h's message flag bits, read by `Uz::info` (fileio.c's
// `UzpMessagePrnt`).
/// unzpriv.h:MSG_STDERR, bit 0: standard error (standard output under `-t`).
pub(crate) const MSG_STDERR: u32 = 0x0001;
/// unzpriv.h:MSG_LNEWLN, bit 5: a leading newline when not at the start of
/// a line.
pub(crate) const MSG_LNEWLN: u32 = 0x0020;
/// unzpriv.h:MSG_TNEWLN, bit 6: a trailing newline when the text lacks one.
pub(crate) const MSG_TNEWLN: u32 = 0x0040;

/// The exit codes the family can return under Apple's flavour (the plan's
/// Global Constraints): 0–3, 4–8 (`PK_MEM*`, only where the reference gives
/// them), 9–11, 50, 51, 80–82. For the `compat` fuzz target (Task 15).
#[doc(hidden)]
pub const EXIT_CODES_APPLE: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 50, 51, 80, 81, 82];
/// [`EXIT_CODES_APPLE`] plus 12 (`PK_BOMB`, ubuntu:
/// 23-cve-2019-13232-zip-bomb-with-overlapped-entries.patch).
#[doc(hidden)]
pub const EXIT_CODES_UBUNTU: &[i32] =
    &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 50, 51, 80, 81, 82];

/// The flavour a build uses when `STUFFR_UNZIP_FLAVOR` is unset or empty:
/// Apple on macOS and the BSDs, Ubuntu everywhere else, Windows included.
pub fn default_flavour() -> Flavour {
    if cfg!(any(
        target_os = "macos",
        target_os = "freebsd",
        target_os = "netbsd",
        target_os = "openbsd",
        target_os = "dragonfly"
    )) {
        Flavour::Apple
    } else {
        Flavour::Ubuntu
    }
}

/// The flavour `STUFFR_UNZIP_FLAVOR`'s value selects: `apple` or `ubuntu`,
/// the default when unset or empty, and `Err(value)` for anything else.
pub(crate) fn flavour_from(value: Option<OsString>) -> Result<Flavour, OsString> {
    match value {
        None => Ok(default_flavour()),
        Some(v) if v.is_empty() => Ok(default_flavour()),
        Some(v) if v == "apple" => Ok(Flavour::Apple),
        Some(v) if v == "ubuntu" => Ok(Flavour::Ubuntu),
        Some(v) => Err(v),
    }
}

/// One run's state: Info-ZIP's `G` (globals.h `Uz_Globs`) with its `uO`
/// ([`cli::Options`]), R5: the command line, the message layer, the
/// archive and entry state, and the window the decoders share.
pub(crate) struct Uz<'a> {
    /// The process, or a sandbox's stand-ins for it.
    pub(crate) host: Host,
    /// Which reference this run behaves as.
    pub(crate) flavour: Flavour,
    /// `G.UzO` (`uO`): the options.
    pub(crate) o: cli::Options,
    /// `getenv`: the process's environment, or a sandbox's stand-in.
    pub(crate) env: &'a dyn Fn(&str) -> Option<OsString>,
    /// Standard output (stdio's `stdout`), flushed after every message as
    /// `UzpMessagePrnt` does.
    pub(crate) out: BufWriter<Box<dyn Write + Send>>,
    /// Standard error.
    pub(crate) err: &'a mut dyn Write,
    /// `G.sol`: the last message ended a line (`TRUE` at start).
    pub(crate) sol: bool,
    /// `G.noargs`: the command line had no arguments at all.
    pub(crate) noargs: bool,
    /// `G.extract_flag`: the run extracts (no `-c -t -l -v -z -T`, not
    /// zipinfo).
    pub(crate) extract_flag: bool,
    /// `G.process_all_files`: no names were given after the archive.
    pub(crate) process_all_files: bool,
    /// `G.native_is_utf8` (ubuntu: -DUTF8_MAYBE_NATIVE): the locale's
    /// codeset is UTF-8 (`fileio::init_locale`; `false` under `LANG=C` and
    /// in a sandbox).
    /// Apple's `fnfilter()` reads the same fact through `isprint()`.
    pub(crate) native_is_utf8: bool,
    /// `G.unicode_escape_all` (ubuntu: -DUNICODE_WCHAR): `-U` given once.
    pub(crate) unicode_escape_all: bool,
    /// `checkdir()`'s state: the extraction root (`G.rootpath`,
    /// `G.rootlen`, Apple's `G.rootdir`: apple: globals.c:164, `-1` at
    /// start) and the path being built (`unix/mapname.rs`).
    pub(crate) ck: unix::mapname::Checkdir,
    /// `G.qf`, what the archive's quarantine gives what is extracted from
    /// it (P7's rewritten value; `NULL`: none; apple: globals.c:165).
    pub(crate) qf: Option<Vec<u8>>,
    /// `G.overwrite_mode`: query, always or never (`extract::OVERWRT_*`).
    pub(crate) overwrite_mode: i32,
    /// `G.answerbuf`: the last answer read from standard input (kept when
    /// an answer finds the end of input).
    pub(crate) answerbuf: [u8; 10],
    /// Standard input as one stdio stream for the run (`fgets(...,
    /// stdin)`), opened at the first question ([`Uz::stdin`]).
    pub(crate) stdin: Option<Box<dyn io::BufRead>>,
    /// `G.key`: the password tried on encrypted entries (zeroed when
    /// dropped).
    pub(crate) key: Option<ttyio::Password>,
    /// `G.nopwd`: no more prompting (`-P`, or "skip all").
    pub(crate) nopwd: bool,
    /// `G.newzip`: no encrypted entry of this archive seen yet.
    pub(crate) newzip: bool,
    /// The run ends with this code: readbyte()'s `EXIT(PK_BADERR)` after a
    /// read error.
    pub(crate) abort: Option<i32>,
    /// What `Info()` formatted into `slide` while a decoder held it, in
    /// order: written to its front when it comes back (P13).
    /// Each is an offset, the bytes and whether a NUL follows them.
    pub(crate) pending_slide: Vec<(usize, Vec<u8>, bool)>,
    /// `G.area.Slide`: the one window every decoder writes into and the
    /// message layer formats into (rulings P13/P16), at least
    /// `stuffr::infozip::WSIZE`, reused across entries. `fnfilter()` and
    /// `do_string()` write into it as the C does.
    pub(crate) slide: Box<[u8]>,
    /// The archive input: `G.zipfd`, `G.inbuf` and `readbuf()`'s state.
    pub(crate) zin: fileio::ZipIn,
    /// `G.wildzipfn`: the archive operand as given.
    pub(crate) wildzipfn: Vec<u8>,
    /// `G.zipfn`: the archive being processed.
    pub(crate) zipfn: Vec<u8>,
    /// `G.pfnames[0..G.filespecs]`: the include patterns.
    pub(crate) pfnames: Vec<Vec<u8>>,
    /// `G.pxnames[0..G.xfilespecs]`: the exclude patterns.
    pub(crate) pxnames: Vec<Vec<u8>>,
    /// `G.no_ecrec`: an earlier candidate had no end record (so the last
    /// chance says "cannot find zipfile directory").
    pub(crate) no_ecrec: bool,
    /// `G.ecrec`: the end-of-central-directory record.
    pub(crate) ecrec: process::Ecrec,
    /// `G.lrec`: the last local header read (getZip64Data() reads it too).
    pub(crate) lrec: process::Lrec,
    /// `G.csize`: the entry's compressed bytes left (a C `zoff_t`).
    pub(crate) csize: i64,
    /// `G.zip64` (ubuntu: 23-cve-2019-13232-zip-bomb-with-overlapped-
    /// entries.patch): cleared by each `getZip64Data()` and set by a Unicode
    /// Path block that `getUnicodeData()` takes (where the patch's hunk
    /// landed), never by a Zip64 block; `extract_or_test_member()`'s data
    /// descriptor skip reads it.
    pub(crate) zip64: bool,
    /// `G.real_ecrec_offset`: where the end record was found.
    pub(crate) real_ecrec_offset: i64,
    /// `G.expect_ecrec_offset`: where the directory says it should be.
    pub(crate) expect_ecrec_offset: i64,
    /// `G.sig`: the last signature read (bytes a short read did not
    /// replace are the earlier ones).
    pub(crate) sig: [u8; 4],
    /// `G.filename`, `FILNAMSIZ` bytes (`flavour::filnamsiz`): the entry's
    /// name as a C string, the bytes past its NUL left from earlier names.
    pub(crate) filename: Vec<u8>,
    /// `G.filename_full` (ubuntu: -DUNICODE_SUPPORT): the last name read,
    /// whole, as a C string, for the Unicode Path checksum; `None` (`NULL`)
    /// until a name is read. Its length is `G.fnfull_bufsize`.
    pub(crate) filename_full: Option<Vec<u8>>,
    /// `G.crec.relative_offset_local_header` as zipinfo's loop last left
    /// it (after `getZip64Data()` for a selected entry): `zipinfo()` starts
    /// the next archive's `endprev` at 4 when it is 4.
    pub(crate) crec_relative_offset_local_header: u64,
    /// `-M`'s pager (globals.h, `MORE`): `G.height`, the lines a screen
    /// holds less two (`SCREENSIZE()`, read at every message).
    pub(crate) height: i32,
    /// `G.width`, the screen's columns (`SCREENLWRAP`: a line that reaches
    /// it counts as two).
    pub(crate) width: i32,
    /// `G.lines`, lines shown since the last full screen.
    pub(crate) lines: i32,
    /// `G.numlines`, every line shown, for `--More--(%lu)`.
    pub(crate) numlines: u64,
    /// `G.chars`, the columns used on the current line.
    pub(crate) chars: i32,
}

impl<'a> Uz<'a> {
    // port: globals.c:globalsCtor
    /// A run's `G` as `globalsCtor()` and Apple's `apple_globals_ctor()`
    /// leave it.
    pub(crate) fn new(
        host: Host,
        flavour: Flavour,
        env: &'a dyn Fn(&str) -> Option<OsString>,
        err: &'a mut dyn Write,
    ) -> Uz<'a> {
        let out = host.out_writer(None);
        Uz {
            host,
            flavour,
            o: cli::Options::new(),
            env,
            out,
            err,
            sol: true, // at start of line
            noargs: false,
            extract_flag: false,
            process_all_files: false,
            native_is_utf8: false,
            unicode_escape_all: false,
            // apple: globals.c:164 (`G.rootdir = -1`)
            ck: unix::mapname::Checkdir::default(),
            // apple: globals.c:165 (`G.qf = NULL`)
            qf: None,
            overwrite_mode: extract::OVERWRT_QUERY,
            answerbuf: [0; 10],
            stdin: None,
            key: None,
            nopwd: false,
            newzip: false,
            abort: None,
            pending_slide: Vec::new(),
            slide: vec![0u8; stuffr::infozip::WSIZE].into_boxed_slice(),
            zin: fileio::ZipIn::new(),
            wildzipfn: Vec::new(),
            zipfn: Vec::new(),
            pfnames: Vec::new(),
            pxnames: Vec::new(),
            no_ecrec: false,
            ecrec: process::Ecrec::default(),
            lrec: process::Lrec::default(),
            csize: 0,
            zip64: false,
            real_ecrec_offset: 0,
            expect_ecrec_offset: 0,
            sig: [0; 4],
            filename: vec![0u8; flavour::filnamsiz(flavour)],
            filename_full: None,
            crec_relative_offset_local_header: 0,
            height: 0,
            width: 0,
            lines: 0,
            numlines: 0,
            chars: 0,
        }
    }

    /// Standard input as stdio's `stdin`: a fill takes what one `read(2)`
    /// returns (a line from a terminal, what a pipe holds), so a question
    /// is answered as soon as its line is typed. A sandbox's is its bytes.
    pub(crate) fn stdin(&mut self) -> &mut dyn io::BufRead {
        if self.stdin.is_none() {
            self.stdin = Some(match self.host {
                Host::Real => Box::new(io::stdin().lock()),
                Host::Sandbox(_) => Box::new(self.host.stdin()),
            });
        }
        self.stdin.as_deref_mut().expect("just opened")
    }

    /// unzip's `EXIT(code)` from inside the run (the pager's `q`): the
    /// process exits with `code` once its output is flushed. A sandbox
    /// cannot exit: the code is kept in `abort`, and the caller returns.
    pub(crate) fn exit_run(&mut self, code: i32) {
        if matches!(self.host, Host::Real) {
            let _ = self.out.flush();
            let _ = self.err.flush();
            std::process::exit(code);
        }
        self.abort = Some(code);
    }

    /// `Info(slide, flag, ((char *)slide, ...))`: the message formatted into
    /// `slide`'s front (and its NUL), as the C's `sprintf` puts it there
    /// (P13), then printed ([`Uz::print_raw`]).
    pub(crate) fn info(&mut self, flag: u32, buf: &[u8]) {
        let owned: Vec<u8>;
        let buf = if flag & MSG_TNEWLN != 0
            && ((buf.is_empty() && !self.sol) || (!buf.is_empty() && buf.last() != Some(&b'\n')))
        {
            // UzpMessagePrnt appends the newline in the buffer itself
            owned = [buf, b"\n"].concat();
            &owned[..]
        } else {
            buf
        };
        self.put_in_slide(buf);
        self.print_raw(flag & !MSG_TNEWLN, buf);
    }

    /// `buf` at `slide`'s front with a NUL after it (or, while a decoder
    /// holds the window, kept for [`Uz::restore_slide`]).
    fn put_in_slide(&mut self, buf: &[u8]) {
        self.put_slide_at(0, buf, true);
    }

    /// `buf` into `slide` at `at`, and a NUL after it when `nul` and it
    /// fits: what `sprintf()` and `fnfilter()` write there. While a decoder
    /// holds the window (`slide` empty) it is kept for
    /// [`Uz::restore_slide`]; a write past the window's end is the C's
    /// never-reached case and is dropped.
    pub(crate) fn put_slide_at(&mut self, at: usize, buf: &[u8], nul: bool) {
        if self.slide.is_empty() {
            self.pending_slide.push((at, buf.to_vec(), nul));
            return;
        }
        let end = at + buf.len();
        if end <= self.slide.len() {
            self.slide[at..end].copy_from_slice(buf);
            if nul && end < self.slide.len() {
                self.slide[end] = 0;
            }
        }
    }

    /// The window is back from a decoder: what `Info()` and `fnfilter()`
    /// wrote meanwhile goes to it, in order (P13).
    pub(crate) fn restore_slide(&mut self) {
        for (at, b, nul) in std::mem::take(&mut self.pending_slide) {
            self.put_slide_at(at, &b, nul);
        }
    }

    // port: fileio.c:UzpMessagePrnt
    /// `(*G.message)(&G, buf, size, flag)`: print `buf` to standard error
    /// when `flag` has [`MSG_STDERR`] and `-t` is not set, else to standard
    /// output, with the leading and trailing newlines `flag` asks for, and
    /// flush. Write errors are ignored, as every `Info()` caller ignores
    /// them. Under `-M` every line shown is counted (a line reaching the
    /// screen's width counts too, `SCREENLWRAP`; no tab expansion, no
    /// `TABSIZE` in either build) and a full screen pauses
    /// ([`fileio::more_pause`], `--More--(N)`).
    pub(crate) fn print_raw(&mut self, flag: u32, buf: &[u8]) {
        let _ = self.message(flag, buf, false);
    }

    /// `(*G.message)(&G, rawbuf, size, 0)` for `-c` and `-p`'s data:
    /// standard output, flushed (and paged under `-M`); a failed write is
    /// returned (flush() then gives up on the entry).
    pub(crate) fn print_data(&mut self, buf: &[u8]) -> io::Result<()> {
        self.message(0, buf, true)
    }

    // port: fileio.c:UzpMessagePrnt
    /// [`Uz::print_raw`] and [`Uz::print_data`]: `strict` returns the first
    /// failed write, as `WriteTxtErr()`'s error is returned; a message's is
    /// ignored, as every `Info()` caller ignores it. After the run's
    /// `EXIT` (`abort`) nothing more is printed: the C has exited.
    fn message(&mut self, flag: u32, buf: &[u8], strict: bool) -> io::Result<()> {
        // ruling: T11-7. Nothing is printed after the run's `EXIT`.
        if self.abort.is_some() {
            return Ok(());
        }
        let to_stderr = flag & MSG_STDERR != 0 && !self.o.tflag;
        let owned: Vec<u8>;
        let buf = if flag & MSG_TNEWLN != 0
            && ((buf.is_empty() && !self.sol) || (!buf.is_empty() && buf.last() != Some(&b'\n')))
        {
            owned = [buf, b"\n"].concat();
            &owned[..]
        } else {
            buf
        };
        if self.o.m_flag {
            // room for --More-- and one line of overlap:
            let (height, width) = ttyio::screensize(&self.host);
            self.height = height - 2;
            self.width = width;
        }
        // error output from testing redirected:  also send to stderr
        let also_stderr = flag & MSG_STDERR != 0
            && self.o.tflag
            && !self.host.stdout_is_tty()
            && self.host.stderr_is_tty();
        if flag & MSG_LNEWLN != 0 && !self.sol {
            // not at start of line:  want newline
            self.emit(to_stderr, b"\n", strict)?;
            if self.o.m_flag {
                self.chars = 0;
                self.numlines += 1;
                self.lines += 1;
                if self.lines >= self.height {
                    self.more();
                    if self.abort.is_some() {
                        // ruling: T11-7 (`q`: the C has exited)
                        return Ok(());
                    }
                }
            }
            if also_stderr {
                let _ = self.err.write_all(b"\n");
                let _ = self.err.flush();
            }
            self.sol = true;
        }

        // put zipfile name, filename and/or error/warning keywords here
        let mut q = 0;
        if self.o.m_flag {
            for p in 0..buf.len() {
                let mut islinefeed = false;
                if buf[p] == b'\n' {
                    islinefeed = true;
                } else if buf[p] == b'\r' {
                    self.chars = 0;
                } else {
                    self.chars += 1;
                    if self.chars >= self.width {
                        islinefeed = true;
                    }
                }
                if islinefeed && self.o.m_flag {
                    // (`-M` off again mid-message: ruling T11-4's end of
                    // input)
                    self.chars = 0;
                    self.numlines += 1;
                    self.lines += 1;
                    if self.lines >= self.height {
                        self.emit(to_stderr, &buf[q..=p], strict)?;
                        self.sol = true;
                        q = p + 1;
                        self.more();
                        if self.abort.is_some() {
                            // ruling: T11-7
                            return Ok(());
                        }
                    }
                }
            }
        }
        let rest = &buf[q..];
        if !rest.is_empty() {
            self.emit(to_stderr, rest, strict)?;
            if also_stderr {
                let _ = self.err.write_all(rest);
                let _ = self.err.flush();
            }
            self.sol = buf.last() == Some(&b'\n');
        }
        Ok(())
    }

    /// `(*G.mpause)(&G, MorePrompt, 1)`.
    fn more(&mut self) {
        let mut prompt = Vec::new();
        printf(
            &mut prompt,
            m::MORE_PROMPT,
            &[self.numlines.to_string().as_bytes()],
        );
        fileio::more_pause(self, &prompt, 1);
    }

    /// `WriteTxtErr(buf, outfp)` + `fflush(outfp)`: the error returned when
    /// `strict`, else ignored.
    fn emit(&mut self, to_stderr: bool, buf: &[u8], strict: bool) -> io::Result<()> {
        if !strict {
            self.write(to_stderr, buf);
            return Ok(());
        }
        let w: &mut dyn Write = if to_stderr {
            &mut *self.err
        } else {
            &mut self.out
        };
        w.write_all(buf)?;
        w.flush()
    }

    /// [`Uz::info`] of `fmt` with its `%s`/`%d` filled from `args`.
    pub(crate) fn info_fmt(&mut self, flag: u32, fmt: &str, args: &[&[u8]]) {
        let mut buf = Vec::new();
        printf(&mut buf, fmt, args);
        self.info(flag, &buf);
    }

    /// One message to one stream, flushed (`WriteTxtErr` + `fflush`).
    fn write(&mut self, to_stderr: bool, buf: &[u8]) {
        if to_stderr {
            let _ = self.err.write_all(buf);
            let _ = self.err.flush();
        } else {
            let _ = self.out.write_all(buf);
            let _ = self.out.flush();
        }
    }
}

/// Entry point for `unzip`, `zipinfo` and `funzip`; `name` is the
/// canonical invoked name, `argv0` the program as invoked (unzip.c reads
/// its last component for ZipInfo mode) and `args` the arguments after it.
pub fn run(name: &'static str, argv0: &OsStr, args: Vec<OsString>) -> ExitCode {
    // Deviation 1: as the other families.
    host::reset_sigpipe();
    let env = |k: &str| std::env::var_os(k);
    let mut err = io::stderr();
    let flavour = match flavour_from(env(FLAVOR_VAR)) {
        Ok(f) => f,
        Err(v) => {
            printf(
                &mut err,
                m::FLAVOR_REFUSED,
                &[name.as_bytes(), v.as_encoded_bytes()],
            );
            return ExitCode::from(1);
        }
    };
    let argv0 = if argv0.is_empty() {
        name.as_bytes()
    } else {
        argv0.as_encoded_bytes()
    };
    let code = main(flavour, name, argv0, &args, &env, Host::Real, &mut err);
    // The process's exit status is the code's low byte, as `exit()` makes
    // it (every code here is below 256).
    ExitCode::from(code as u8)
}

/// [`run`] without the process, as `flavour` (R7): operands resolve against
/// `dir`, standard input is `stdin` (a pipe of bytes), standard output and
/// error are captured and returned with the exit code and what each input
/// read, neither is a terminal, `env` stands in for the environment
/// (`UNZIP`, `UNZIPOPT`, `ZIPINFO`, `ZIPINFOOPT`; `STUFFR_UNZIP_FLAVOR` is
/// not consulted), no signal is touched, and standard output and output
/// files share the [`SANDBOX_OUTPUT_CAP`] budget. For the fuzz target; not
/// a stable interface.
#[doc(hidden)]
pub fn run_in_counted(
    flavour: Flavour,
    dir: &Path,
    name: &'static str,
    args: &[OsString],
    stdin: &[u8],
    env: &dyn Fn(&str) -> Option<OsString>,
) -> CountedRun {
    let stdout = Arc::new(Mutex::new(Vec::new()));
    let reads = Arc::new(Mutex::new(BTreeMap::new()));
    let host = Host::Sandbox(Sandbox {
        dir: dir.to_path_buf(),
        stdin: Some(stdin.to_vec()),
        stdout: stdout.clone(),
        budget: Arc::new(AtomicU64::new(SANDBOX_OUTPUT_CAP)),
        reads: reads.clone(),
    });
    let mut err = Vec::new();
    let code = main(flavour, name, name.as_bytes(), args, env, host, &mut err);
    let out = std::mem::take(&mut *stdout.lock().unwrap_or_else(|p| p.into_inner()));
    let reads = std::mem::take(&mut *reads.lock().unwrap_or_else(|p| p.into_inner()));
    (code, out, err, reads)
}

/// The run below the process boundary. Returns the exit code.
fn main(
    flavour: Flavour,
    name: &str,
    argv0: &[u8],
    args: &[OsString],
    env: &dyn Fn(&str) -> Option<OsString>,
    host: Host,
    err: &mut dyn Write,
) -> i32 {
    if name == "funzip" {
        let mut uz = Uz::new(host, flavour, env, err);
        return funzip::funzip(&mut uz, args);
    }
    // port: unzip.c:unzip (`SET_SIGHANDLER(SIGINT, handler)` and its
    // siblings): for the whole run, an interrupt puts the terminal's echo
    // back and exits with IZ_CTRLC, leaving a partial output in place.
    // probe: `kill -INT`/`-TERM`/`-ABRT` during `unzip big.zip` (Apple's and
    // Ubuntu's): exit 80, nothing printed, `big.bin` kept, also under an
    // inherited `SIG_IGN`; SIGHUP and SIGQUIT kill it.
    let _interrupt =
        host::arm_interrupt_exit(&host, host::UNZIP_SIGNALS, IZ_CTRLC, m::HANDLER_TEXT);
    let mut uz = Uz::new(host, flavour, env, err);
    uz.native_is_utf8 = fileio::init_locale(&uz.host);
    // ubuntu: 20-unzip60-alt-iconv-utf8.patch (unzip.c: `#ifdef UNIX
    // init_conversion_charsets()`, before the options are read)
    if flavour::iconv_charsets(flavour) {
        unix::charset::init_conversion_charsets(&mut uz);
    }
    let code = unzip(&mut uz, argv0, args);
    let _ = uz.out.flush();
    code
}

/// Whether `s` begins with `prefix`, ignoring ASCII case (`STRNICMP(s,
/// prefix, n) == 0` with `n` the prefix's length).
fn starts_with_ignore_case(s: &[u8], prefix: &[u8]) -> bool {
    s.len() >= prefix.len() && s[..prefix.len()].eq_ignore_ascii_case(prefix)
}

// port: unzip.c:unzip
/// unzip.c's `unzip()`: ZipInfo mode or UnZip mode, the command line, then
/// the archives.
fn unzip(uz: &mut Uz, argv0: &[u8], args: &[OsString]) -> i32 {
    // The program name's last component (after `DIR_END`).
    let start = argv0
        .iter()
        .rposition(|&b| b == b'/' || (cfg!(windows) && b == b'\\'))
        .map_or(0, |i| i + 1);
    let p = &argv0[start..];
    let zipinfo = starts_with_ignore_case(p, b"zipinfo")
        || starts_with_ignore_case(p, b"ii")
        || args
            .first()
            .is_some_and(|a| a.as_encoded_bytes().starts_with(b"-Z"));
    let parsed = if zipinfo {
        cli::parse_zipinfo(uz, args)
    } else {
        cli::parse_unzip(uz, args)
    };
    match parsed {
        Ok(p) => process_zipfiles(uz, &p),
        Err(code) => code,
    }
}

/// `process.c`'s `process_zipfiles()`.
fn process_zipfiles(uz: &mut Uz, parsed: &cli::Parsed) -> i32 {
    process::process_zipfiles(uz, parsed)
}

#[cfg(test)]
mod tests {
    use super::*;

    fn run(f: Flavour, name: &'static str, args: &[&str]) -> (i32, String, String) {
        let args: Vec<OsString> = args.iter().map(OsString::from).collect();
        let dir = std::env::temp_dir();
        let (code, out, err, _) = run_in_counted(f, &dir, name, &args, b"", &|_| None);
        (
            code,
            String::from_utf8(out).unwrap(),
            String::from_utf8(err).unwrap(),
        )
    }

    #[test]
    fn the_default_flavour_follows_the_platform() {
        let apple = cfg!(any(
            target_os = "macos",
            target_os = "freebsd",
            target_os = "netbsd",
            target_os = "openbsd",
            target_os = "dragonfly"
        ));
        let want = if apple {
            Flavour::Apple
        } else {
            Flavour::Ubuntu
        };
        assert_eq!(default_flavour(), want);
    }

    /// Each flavour's banners say whose build they alter (R2), with this
    /// stuffr's version.
    #[test]
    fn banners_name_stuffr_and_the_build() {
        let v = env!("CARGO_PKG_VERSION");
        let (code, out, err) = run(Flavour::Apple, "unzip", &[]);
        assert_eq!((code, err.as_str()), (0, ""));
        let want = format!(
            "UnZip 6.00 of 20 April 2009, by stuffr {v} (altered; original by Info-ZIP, \
             with modifications by Apple Inc.).\nPlease report bugs to Apple.\n\nUsage: "
        );
        assert!(out.starts_with(&want), "{out}");
        let (_, out, _) = run(Flavour::Ubuntu, "unzip", &["-h"]);
        let want = format!(
            "UnZip 6.00 of 20 April 2009, by stuffr {v} (altered; Debian's build, original \
             by Info-ZIP).\n\nUsage: "
        );
        assert!(out.starts_with(&want), "{out}");
        let (code, out, _) = run(Flavour::Apple, "zipinfo", &[]);
        assert_eq!(code, 0);
        assert!(
            out.starts_with(&format!(
                "ZipInfo 3.00 of 20 April 2009, by stuffr {v} (altered; original by Greg \
                 Roelofs and the Info-ZIP group, with modifications by Apple Inc.).\n\nList"
            )),
            "{out}"
        );
        let (_, out, _) = run(Flavour::Ubuntu, "unzip", &["-Z"]);
        assert!(
            out.starts_with(&format!(
                "ZipInfo 3.00 of 20 April 2009, by stuffr {v} (altered; Debian's build, \
                 original by Greg Roelofs and the Info-ZIP group).\n"
            )),
            "{out}"
        );
        // deviation 2: the Apple line is the recorded build's, pinned exactly
        let (_, out, _) = run(Flavour::Apple, "unzip", &["-v"]);
        assert!(
            out.contains(
                "\nCompiled with gcc Apple LLVM 21.0.0 (clang-2100.3.31.1) [+internal-os] \
                 for Unix Mac OS X on Aug  8 2026.\n\n"
            ),
            "{out}"
        );
        let (_, out, _) = run(Flavour::Ubuntu, "unzip", &["-v"]);
        assert!(
            out.contains("\nCompiled with gcc 13.2.0 for Unix (Linux ELF).\n\n"),
            "{out}"
        );
    }

    /// A command line that gets past the parser (an archive operand,
    /// funzip without a terminal) does not panic and exits with one of the
    /// flavour's codes. What it answers is the archive tasks' to pin.
    #[test]
    fn past_the_parser_a_run_never_panics() {
        for f in [Flavour::Apple, Flavour::Ubuntu] {
            let codes = match f {
                Flavour::Apple => EXIT_CODES_APPLE,
                Flavour::Ubuntu => EXIT_CODES_UBUNTU,
            };
            for (name, args) in [
                ("funzip", &[][..]),
                ("unzip", &["-l", "a.zip", "x", "-x", "y"]),
                ("zipinfo", &["a.zip"]),
            ] {
                let (code, _, _) = run(f, name, args);
                assert!(codes.contains(&code), "{f:?} {name} {args:?}: exit {code}");
            }
        }
    }

    /// The exit-code tables differ by `PK_BOMB` only.
    #[test]
    fn ubuntu_adds_only_pk_bomb() {
        let extra: Vec<i32> = EXIT_CODES_UBUNTU
            .iter()
            .copied()
            .filter(|c| !EXIT_CODES_APPLE.contains(c))
            .collect();
        assert_eq!(extra, [12]);
        assert!(
            EXIT_CODES_APPLE
                .iter()
                .all(|c| EXIT_CODES_UBUNTU.contains(c))
        );
    }
}