Move pts to rust, and avoid using thread

native/src/Android.mk

@@ -27,7 +27,6 @@ LOCAL_SRC_FILES := \
     core/resetprop/resetprop.cpp \
     core/su/su.cpp \
     core/su/connect.cpp \
-    core/su/pts.cpp \
     core/zygisk/entry.cpp \
     core/zygisk/module.cpp \
     core/zygisk/hook.cpp \

native/src/core/lib.rs

@@ -16,6 +16,7 @@ use logging::{android_logging, setup_logfile, zygisk_close_logd, zygisk_get_logd
 use mount::{find_preinit_device, revert_unmount};
 use resetprop::{persist_delete_prop, persist_get_prop, persist_get_props, persist_set_prop};
 use socket::{recv_fd, recv_fds, send_fd, send_fds};
+use su::{pump_stdin_stdout, get_pty_num, restore_stdin};
 use std::fs::File;
 use std::mem::ManuallyDrop;
 use std::ops::DerefMut;
@@ -207,6 +208,10 @@ pub mod ffi {
 
         #[namespace = "rust"]
         fn daemon_entry();
+
+        fn pump_stdin_stdout(infd: i32, outfd: i32);
+        fn get_pty_num(fd: i32) -> i32;
+        fn restore_stdin() -> bool;
     }
 
     // Default constructors

native/src/core/su/mod.rs

@@ -1,4 +1,6 @@
 mod daemon;
 mod db;
+mod pts;
 
 pub use daemon::SuInfo;
+pub use pts::{pump_stdin_stdout, get_pty_num, restore_stdin};

native/src/core/su/pts.cpp

@@ -1,294 +0,0 @@
-/*
- * Copyright 2013, Tan Chee Eng (@tan-ce)
- */
-
- /*
- * pts.c
- *
- * Manages the pseudo-terminal driver on Linux/Android and provides some
- * helper functions to handle raw input mode and terminal window resizing
- */
-
-#include <unistd.h>
-#include <fcntl.h>
-#include <termios.h>
-
-#include <base.hpp>
-
-#include "pts.hpp"
-
-/**
- * Helper functions
- */
-// Ensures all the data is written out
-static int write_blocking(int fd, char *buf, ssize_t bufsz) {
-    ssize_t ret, written;
-
-    written = 0;
-    do {
-        ret = write(fd, buf + written, bufsz - written);
-        if (ret == -1) return -1;
-        written += ret;
-    } while (written < bufsz);
-
-    return 0;
-}
-
-/**
- * Pump data from input FD to output FD. If close_output is
- * true, then close the output FD when we're done.
- */
-static void pump(int input, int output, bool close_output = true) {
-    char buf[4096];
-    int len;
-    while ((len = read(input, buf, 4096)) > 0) {
-        if (write_blocking(output, buf, len) == -1) break;
-    }
-    close(input);
-    if (close_output) close(output);
-}
-
-static void* pump_thread(void* data) {
-    int *fds = (int*) data;
-    pump(fds[0], fds[1]);
-    delete[] fds;
-    return nullptr;
-}
-
-static void pump_async(int input, int output) {
-    pthread_t writer;
-    int *fds = new int[2];
-    fds[0] = input;
-    fds[1] = output;
-    pthread_create(&writer, nullptr, pump_thread, fds);
-}
-
-
-/**
- * pts_open
- *
- * Opens a pts device and returns the name of the slave tty device.
- *
- * Arguments
- * slave_name       the name of the slave device
- * slave_name_size  the size of the buffer passed via slave_name
- *
- * Return Values
- * on failure either -2 or -1 (errno set) is returned.
- * on success, the file descriptor of the master device is returned.
- */
-int pts_open(char *slave_name, size_t slave_name_size) {
-    int fdm;
-
-    // Open master ptmx device
-    fdm = open("/dev/ptmx", O_RDWR);
-    if (fdm == -1)
-        goto error;
-
-    // Get the slave name
-    if (ptsname_r(fdm, slave_name, slave_name_size - 1))
-        goto error;
-
-    slave_name[slave_name_size - 1] = '\0';
-
-    // Grant, then unlock
-    if (grantpt(fdm) == -1)
-        goto error;
-
-    if (unlockpt(fdm) == -1)
-        goto error;
-
-    return fdm;
-error:
-    close(fdm);
-    PLOGE("pts_open");
-    return -1;
-}
-
-int get_pty_num(int fd) {
-    int pty_num = -1;
-    if (ioctl(fd, TIOCGPTN, &pty_num) != 0) {
-        LOGW("get_pty_num failed with %d: %s\n", errno, std::strerror(errno));
-        return -1;
-    }
-    return pty_num;
-}
-
-// Stores the previous termios of stdin
-static struct termios old_stdin;
-static int stdin_is_raw = 0;
-
-/**
- * set_stdin_raw
- *
- * Changes stdin to raw unbuffered mode, disables echo,
- * auto carriage return, etc.
- *
- * Return Value
- * on failure -1, and errno is set
- * on success 0
- */
-int set_stdin_raw() {
-    struct termios termios{};
-
-    if (tcgetattr(STDIN_FILENO, &termios) < 0) {
-        return -1;
-    }
-
-    old_stdin = termios;
-
-    cfmakeraw(&termios);
-
-    if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &termios) < 0) {
-        // https://blog.zhanghai.me/fixing-line-editing-on-android-8-0/
-        if (tcsetattr(STDIN_FILENO, TCSADRAIN, &termios) < 0) {
-            return -1;
-        }
-    }
-
-    stdin_is_raw = 1;
-
-    return 0;
-}
-
-/**
- * restore_stdin
- *
- * Restore termios on stdin to the state it was before
- * set_stdin_raw() was called. If set_stdin_raw() was
- * never called, does nothing and doesn't return an error.
- *
- * This function is async-safe.
- *
- * Return Value
- * on failure, -1 and errno is set
- * on success, 0
- */
-int restore_stdin() {
-    if (!stdin_is_raw) return 0;
-
-    if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &old_stdin) < 0) {
-        if (tcsetattr(STDIN_FILENO, TCSADRAIN, &old_stdin) < 0) {
-            return -1;
-        }
-    }
-
-    stdin_is_raw = 0;
-
-    return 0;
-}
-
-// Flag indicating whether the sigwinch watcher should terminate.
-static volatile bool close_sigwinch_watcher = false;
-
-/**
- * Thread process. Wait for a SIGWINCH to be received, then update
- * the terminal size.
- */
-static void *watch_sigwinch(void *data) {
-    sigset_t winch;
-    int *fds = (int *)data;
-    int sig;
-
-    sigemptyset(&winch);
-    sigaddset(&winch, SIGWINCH);
-    pthread_sigmask(SIG_UNBLOCK, &winch, nullptr);
-
-    do {
-        if (close_sigwinch_watcher)
-            break;
-
-        // Get the new terminal size
-        struct winsize w;
-        if (ioctl(fds[0], TIOCGWINSZ, &w) == -1)
-            continue;
-
-        // Set the new terminal size
-        ioctl(fds[1], TIOCSWINSZ, &w);
-
-    } while (sigwait(&winch, &sig) == 0);
-    delete[] fds;
-
-    return nullptr;
-}
-
-/**
- * watch_sigwinch_async
- *
- * After calling this function, if the application receives
- * SIGWINCH, the terminal window size will be read from
- * "input" and set on "output".
- *
- * NOTE: This function blocks SIGWINCH and spawns a thread.
- * NOTE 2: This function must be called before any of the
- *         pump functions.
- *
- * Arguments
- * master   A file descriptor of the TTY window size to follow
- * slave    A file descriptor of the TTY window size which is
- *          to be set on SIGWINCH
- *
- * Return Value
- * on failure, -1 and errno will be set. In this case, no
- *      thread has been spawned and SIGWINCH will not be
- *      blocked.
- * on success, 0
- */
-int watch_sigwinch_async(int master, int slave) {
-    pthread_t watcher;
-    int *fds = new int[2];
-
-    // Block SIGWINCH so sigwait can later receive it
-    sigset_t winch;
-    sigemptyset(&winch);
-    sigaddset(&winch, SIGWINCH);
-    if (pthread_sigmask(SIG_BLOCK, &winch, nullptr) == -1) {
-        delete[] fds;
-        return -1;
-    }
-
-    // Initialize some variables, then start the thread
-    close_sigwinch_watcher = 0;
-    fds[0] = master;
-    fds[1] = slave;
-    int ret = pthread_create(&watcher, nullptr, &watch_sigwinch, fds);
-    if (ret != 0) {
-        delete[] fds;
-        errno = ret;
-        return -1;
-    }
-
-    return 0;
-}
-
-/**
- * pump_stdin_async
- *
- * Forward data from STDIN to the given FD
- * in a separate thread
- */
-void pump_stdin_async(int outfd) {
-    // Put stdin into raw mode
-    set_stdin_raw();
-
-    // Pump data from stdin to the PTY
-    pump_async(STDIN_FILENO, outfd);
-}
-
-/**
- * pump_stdout_blocking
- *
- * Forward data from the FD to STDOUT.
- * Returns when the remote end of the FD closes.
- *
- * Before returning, restores stdin settings.
- */
-void pump_stdout_blocking(int infd) {
-    // Pump data from stdout to PTY
-    pump(infd, STDOUT_FILENO, false /* Don't close output when done */);
-
-    // Cleanup
-    restore_stdin();
-    close_sigwinch_watcher = true;
-    raise(SIGWINCH);
-}

native/src/core/su/pts.hpp

@@ -1,102 +0,0 @@
-/*
- * Copyright 2013, Tan Chee Eng (@tan-ce)
- */
-
- /*
- * pts.hpp
- *
- * Manages the pseudo-terminal driver on Linux/Android and provides some
- * helper functions to handle raw input mode and terminal window resizing
- */
-
-#ifndef _PTS_H_
-#define _PTS_H_
-
-#include <sys/types.h>
-
-/**
- * pts_open
- *
- * Opens a pts device and returns the name of the slave tty device.
- *
- * Arguments
- * slave_name       the name of the slave device
- * slave_name_size  the size of the buffer passed via slave_name
- *
- * Return Values
- * on failure either -2 or -1 (errno set) is returned.
- * on success, the file descriptor of the master device is returned.
- */
-int pts_open(char *slave_name, size_t slave_name_size);
-
-
-int get_pty_num(int fd);
-
-/**
- * set_stdin_raw
- *
- * Changes stdin to raw unbuffered mode, disables echo,
- * auto carriage return, etc.
- *
- * Return Value
- * on failure -1, and errno is set
- * on success 0
- */
-int set_stdin_raw(void);
-
-/**
- * restore_stdin
- *
- * Restore termios on stdin to the state it was before
- * set_stdin_raw() was called. If set_stdin_raw() was
- * never called, does nothing and doesn't return an error.
- *
- * This function is async-safe.
- *
- * Return Value
- * on failure, -1 and errno is set
- * on success, 0
- */
-int restore_stdin(void);
-
-/**
- * watch_sigwinch_async
- *
- * After calling this function, if the application receives
- * SIGWINCH, the terminal window size will be read from
- * "input" and set on "output".
- *
- * NOTE: This function blocks SIGWINCH and spawns a thread.
- *
- * Arguments
- * master   A file descriptor of the TTY window size to follow
- * slave    A file descriptor of the TTY window size which is
- *          to be set on SIGWINCH
- *
- * Return Value
- * on failure, -1 and errno will be set. In this case, no
- *      thread has been spawned and SIGWINCH will not be
- *      blocked.
- * on success, 0
- */
-int watch_sigwinch_async(int master, int slave);
-
-/**
- * pump_stdin_async
- *
- * Forward data from STDIN to the given FD
- * in a separate thread
- */
-void pump_stdin_async(int outfd);
-
-/**
- * pump_stdout_blocking
- *
- * Forward data from the FD to STDOUT.
- * Returns when the remote end of the FD closes.
- *
- * Before returning, restores stdin settings.
- */
-void pump_stdout_blocking(int infd);
-
-#endif

native/src/core/su/pts.rs

@@ -0,0 +1,133 @@
+use base::{
+    error,
+    libc::{
+        POLLIN, SFD_CLOEXEC, SIG_BLOCK, SIGWINCH, STDOUT_FILENO, TCSADRAIN, TCSAFLUSH, TIOCGWINSZ,
+        TIOCSWINSZ, cfmakeraw, close, poll, pollfd, raise, read, sigaddset, sigemptyset, signalfd,
+        sigprocmask, sigset_t, tcsetattr, winsize, write,
+    },
+    libc::{STDIN_FILENO, ioctl, tcgetattr, termios},
+    warn,
+};
+use std::ptr::null_mut;
+
+static mut OLD_STDIN: Option<termios> = None;
+
+pub fn get_pty_num(fd: i32) -> i32 {
+    let mut pty_num = -1i32;
+    if unsafe { ioctl(fd, 0x80045430u32 as _, &mut pty_num) } != 0 {
+        warn!("Failed to get pty number");
+    }
+    pty_num
+}
+
+fn set_stdin_raw() -> bool {
+    unsafe {
+        let mut termios: termios = std::mem::zeroed();
+
+        if tcgetattr(STDIN_FILENO, &mut termios) < 0 {
+            return false;
+        }
+
+        OLD_STDIN = Some(termios);
+
+        cfmakeraw(&mut termios);
+
+        if tcsetattr(STDIN_FILENO, TCSAFLUSH, &termios) < 0
+            && tcsetattr(STDIN_FILENO, TCSADRAIN, &termios) < 0
+        {
+            warn!("Failed to set terminal attributes");
+            return false;
+        }
+    }
+
+    true
+}
+
+pub fn restore_stdin() -> bool {
+    unsafe {
+        if let Some(ref termios) = OLD_STDIN {
+            if tcsetattr(STDIN_FILENO, TCSAFLUSH, termios) < 0
+                && tcsetattr(STDIN_FILENO, TCSADRAIN, termios) < 0
+            {
+                warn!("Failed to restore terminal attributes");
+                return false;
+            }
+        }
+        OLD_STDIN = None;
+        true
+    }
+}
+
+fn resize_pty(outfd: i32) {
+    let mut ws: winsize = unsafe { std::mem::zeroed() };
+    if unsafe { ioctl(STDIN_FILENO, TIOCGWINSZ, &mut ws) } >= 0 {
+        unsafe { ioctl(outfd, TIOCSWINSZ, &ws) };
+    }
+}
+
+pub fn pump_stdin_stdout(infd: i32, outfd: i32) {
+    set_stdin_raw();
+
+    let sfd = unsafe {
+        let mut mask: sigset_t = std::mem::zeroed();
+        sigemptyset(&mut mask);
+        sigaddset(&mut mask, SIGWINCH);
+        if sigprocmask(SIG_BLOCK, &mask, null_mut()) < 0 {
+            error!("sigprocmask");
+        }
+        signalfd(-1, &mask, SFD_CLOEXEC)
+    };
+
+    resize_pty(outfd);
+
+    let mut pfds = [
+        pollfd {
+            fd: STDIN_FILENO,
+            events: POLLIN,
+            revents: 0,
+        },
+        pollfd {
+            fd: infd,
+            events: POLLIN,
+            revents: 0,
+        },
+        pollfd {
+            fd: sfd,
+            events: POLLIN,
+            revents: 0,
+        },
+    ];
+
+    let mut buf = [0u8; 4096];
+    'poll: loop {
+        let ready = unsafe { poll(pfds.as_mut_ptr(), pfds.len() as _, -1) };
+
+        if ready < 0 {
+            error!("poll error");
+            break;
+        }
+
+        for pfd in &pfds {
+            if pfd.revents & POLLIN != 0 {
+                let n = unsafe { read(pfd.fd, buf.as_mut_ptr() as _, buf.len()) };
+                if n <= 0 {
+                    error!("read error");
+                    break 'poll;
+                }
+                if pfd.fd == STDIN_FILENO {
+                    unsafe { write(outfd, buf.as_ptr() as _, n as _) };
+                } else if pfd.fd == infd {
+                    unsafe { write(STDOUT_FILENO, buf.as_ptr() as _, n as _) };
+                } else if pfd.fd == sfd {
+                    resize_pty(outfd);
+                }
+            } else if pfd.revents != 0 && pfd.fd == infd {
+                unsafe { close(pfd.fd) };
+                break 'poll;
+            }
+        }
+    }
+
+    restore_stdin();
+    unsafe { raise(SIGWINCH) };
+}

native/src/core/su/su.cpp

@@ -20,8 +20,6 @@
 #include <flags.h>
 #include <core.hpp>
 
-#include "pts.hpp"
-
 using namespace std;
 
 #define DEFAULT_SHELL "/system/bin/sh"
@@ -241,9 +239,7 @@ int su_client_main(int argc, char *argv[]) {
 
     if (atty) {
         setup_sighandlers(sighandler);
-        watch_sigwinch_async(STDOUT_FILENO, ptmx);
-        pump_stdin_async(ptmx);
-        pump_stdout_blocking(ptmx);
+        pump_stdin_stdout(ptmx, ptmx);
     }
 
     // Get the exit code