1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
//! Standard symbolic constants and types
//!
use {Error, Result, NixPath, from_ffi};
use errno::Errno;
use fcntl::{fcntl, OFlag, O_NONBLOCK, O_CLOEXEC, FD_CLOEXEC};
use fcntl::FcntlArg::{F_SETFD, F_SETFL};
use libc::{c_char, c_void, c_int, size_t, pid_t, off_t};
use std::mem;
use std::ffi::CString;
use std::os::unix::io::RawFd;

#[cfg(any(target_os = "linux", target_os = "android"))]
pub use self::linux::*;

mod ffi {
    use libc::{c_char, c_int, size_t};
    pub use libc::{close, read, write, pipe, ftruncate, unlink};
    pub use libc::funcs::posix88::unistd::{fork, getpid, getppid};

    extern {
        // duplicate a file descriptor
        // doc: http://man7.org/linux/man-pages/man2/dup.2.html
        pub fn dup(oldfd: c_int) -> c_int;
        pub fn dup2(oldfd: c_int, newfd: c_int) -> c_int;

        // change working directory
        // doc: http://man7.org/linux/man-pages/man2/chdir.2.html
        pub fn chdir(path: *const c_char) -> c_int;

        // Execute PATH with arguments ARGV and environment from `environ'.
        // doc: http://man7.org/linux/man-pages/man3/execv.3.html
        pub fn execv (path: *const c_char, argv: *const *const c_char) -> c_int;

        // execute program
        // doc: http://man7.org/linux/man-pages/man2/execve.2.html
        pub fn execve(path: *const c_char, argv: *const *const c_char, envp: *const *const c_char) -> c_int;

        // Execute FILE, searching in the `PATH' environment variable if it contains
        // no slashes, with arguments ARGV and environment from `environ'.
        // doc: http://man7.org/linux/man-pages/man3/execvp.3.html
        pub fn execvp(filename: *const c_char, argv: *const *const c_char) -> c_int;

        // doc: http://man7.org/linux/man-pages/man3/exec.3.html
        #[cfg(any(target_os = "linux", target_os = "android"))]
        #[cfg(feature = "execvpe")]
        pub fn execvpe(filename: *const c_char, argv: *const *const c_char, envp: *const *const c_char) -> c_int;

        // run the current process in the background
        // doc: http://man7.org/linux/man-pages/man3/daemon.3.html
        pub fn daemon(nochdir: c_int, noclose: c_int) -> c_int;

        // sets the hostname to the value given
        // doc: http://man7.org/linux/man-pages/man2/gethostname.2.html
        pub fn gethostname(name: *mut c_char, len: size_t) -> c_int;

        // gets the hostname
        // doc: http://man7.org/linux/man-pages/man2/gethostname.2.html
        pub fn sethostname(name: *const c_char, len: size_t) -> c_int;

        // change root directory
        // doc: http://man7.org/linux/man-pages/man2/gethostname.2.html
        pub fn chroot(path: *const c_char) -> c_int;
    }
}

#[derive(Clone, Copy)]
pub enum Fork {
    Parent(pid_t),
    Child
}

impl Fork {
    pub fn is_child(&self) -> bool {
        match *self {
            Fork::Child => true,
            _ => false
        }
    }

    pub fn is_parent(&self) -> bool {
        match *self {
            Fork::Parent(_) => true,
            _ => false
        }
    }
}

pub fn fork() -> Result<Fork> {
    use self::Fork::*;

    let res = unsafe { ffi::fork() };

    if res < 0 {
        return Err(Error::Sys(Errno::last()));
    } else if res == 0 {
        Ok(Child)
    } else {
        Ok(Parent(res))
    }
}

#[inline]
pub fn getpid() -> pid_t {
    unsafe { ffi::getpid() } // no error handling, according to man page: "These functions are always successful."
}
#[inline]
pub fn getppid() -> pid_t {
    unsafe { ffi::getppid() } // no error handling, according to man page: "These functions are always successful."
}

#[inline]
pub fn dup(oldfd: RawFd) -> Result<RawFd> {
    let res = unsafe { ffi::dup(oldfd) };

    if res < 0 {
        return Err(Error::Sys(Errno::last()));
    }

    Ok(res)
}

#[inline]
pub fn dup2(oldfd: RawFd, newfd: RawFd) -> Result<RawFd> {
    let res = unsafe { ffi::dup2(oldfd, newfd) };

    if res < 0 {
        return Err(Error::Sys(Errno::last()));
    }

    Ok(res)
}

pub fn dup3(oldfd: RawFd, newfd: RawFd, flags: OFlag) -> Result<RawFd> {
    dup3_polyfill(oldfd, newfd, flags)
}

#[inline]
fn dup3_polyfill(oldfd: RawFd, newfd: RawFd, flags: OFlag) -> Result<RawFd> {
    use errno::EINVAL;

    if oldfd == newfd {
        return Err(Error::Sys(Errno::EINVAL));
    }

    let fd = try!(dup2(oldfd, newfd));

    if flags.contains(O_CLOEXEC) {
        if let Err(e) = fcntl(fd, F_SETFD(FD_CLOEXEC)) {
            let _ = close(fd);
            return Err(e);
        }
    }

    Ok(fd)
}

#[inline]
pub fn chdir<P: ?Sized + NixPath>(path: &P) -> Result<()> {
    let res = try!(path.with_nix_path(|cstr| {
        unsafe { ffi::chdir(cstr.as_ptr()) }
    }));

    if res != 0 {
        return Err(Error::Sys(Errno::last()));
    }

    return Ok(())
}

fn to_exec_array(args: &[CString]) -> *const *const c_char {
    use std::ptr;
    use libc::c_char;

    let mut args_p: Vec<*const c_char> = args.iter().map(|s| s.as_ptr()).collect();
    args_p.push(ptr::null());
    args_p.as_ptr()
}

#[inline]
pub fn execv(path: &CString, argv: &[CString]) -> Result<()> {
    let args_p = to_exec_array(argv);

    unsafe {
        ffi::execv(path.as_ptr(), args_p)
    };

    Err(Error::Sys(Errno::last()))
}

#[inline]
pub fn execve(path: &CString, args: &[CString], env: &[CString]) -> Result<()> {
    let args_p = to_exec_array(args);
    let env_p = to_exec_array(env);

    unsafe {
        ffi::execve(path.as_ptr(), args_p, env_p)
    };

    Err(Error::Sys(Errno::last()))
}

#[inline]
pub fn execvp(filename: &CString, args: &[CString]) -> Result<()> {
    let args_p = to_exec_array(args);

    unsafe {
        ffi::execvp(filename.as_ptr(), args_p)
    };

    Err(Error::Sys(Errno::last()))
}

pub fn daemon(nochdir: bool, noclose: bool) -> Result<()> {
    let res = unsafe { ffi::daemon(nochdir as c_int, noclose as c_int) };
    from_ffi(res)
}

pub fn sethostname(name: &[u8]) -> Result<()> {
    let ptr = name.as_ptr() as *const c_char;
    let len = name.len() as size_t;

    let res = unsafe { ffi::sethostname(ptr, len) };
    from_ffi(res)
}

pub fn gethostname(name: &mut [u8]) -> Result<()> {
    let ptr = name.as_mut_ptr() as *mut c_char;
    let len = name.len() as size_t;

    let res = unsafe { ffi::gethostname(ptr, len) };
    from_ffi(res)
}

pub fn close(fd: RawFd) -> Result<()> {
    let res = unsafe { ffi::close(fd) };
    from_ffi(res)
}

pub fn read(fd: RawFd, buf: &mut [u8]) -> Result<usize> {
    let res = unsafe { ffi::read(fd, buf.as_mut_ptr() as *mut c_void, buf.len() as size_t) };

    if res < 0 {
        return Err(Error::Sys(Errno::last()));
    }

    return Ok(res as usize)
}

pub fn write(fd: RawFd, buf: &[u8]) -> Result<usize> {
    let res = unsafe { ffi::write(fd, buf.as_ptr() as *const c_void, buf.len() as size_t) };

    if res < 0 {
        return Err(Error::Sys(Errno::last()));
    }

    return Ok(res as usize)
}

pub fn pipe() -> Result<(RawFd, RawFd)> {
    unsafe {
        let mut fds: [c_int; 2] = mem::uninitialized();

        let res = ffi::pipe(fds.as_mut_ptr());

        if res < 0 {
            return Err(Error::Sys(Errno::last()));
        }

        Ok((fds[0], fds[1]))
    }
}

pub fn pipe2(flags: OFlag) -> Result<(RawFd, RawFd)> {
    unsafe {
        let mut fds: [c_int; 2] = mem::uninitialized();

        let res = ffi::pipe(fds.as_mut_ptr());

        if res < 0 {
            return Err(Error::Sys(Errno::last()));
        }

        try!(pipe2_setflags(fds[0], fds[1], flags));

        Ok((fds[0], fds[1]))
    }
}

fn pipe2_setflags(fd1: RawFd, fd2: RawFd, flags: OFlag) -> Result<()> {
    let mut res = Ok(0);

    if flags.contains(O_CLOEXEC) {
        res = res
            .and_then(|_| fcntl(fd1, F_SETFD(FD_CLOEXEC)))
            .and_then(|_| fcntl(fd2, F_SETFD(FD_CLOEXEC)));
    }

    if flags.contains(O_NONBLOCK) {
        res = res
            .and_then(|_| fcntl(fd1, F_SETFL(O_NONBLOCK)))
            .and_then(|_| fcntl(fd2, F_SETFL(O_NONBLOCK)));
    }

    match res {
        Ok(_) => Ok(()),
        Err(e) => {
            let _ = close(fd1);
            let _ = close(fd2);
            return Err(e);
        }
    }
}

pub fn ftruncate(fd: RawFd, len: off_t) -> Result<()> {
    if unsafe { ffi::ftruncate(fd, len) } < 0 {
        Err(Error::Sys(Errno::last()))
    } else {
        Ok(())
    }
}

pub fn isatty(fd: RawFd) -> Result<bool> {
    use libc;

    if unsafe { libc::isatty(fd) } == 1 {
        Ok(true)
    } else {
        match Errno::last() {
            // ENOTTY means `fd` is a valid file descriptor, but not a TTY, so
            // we return `Ok(false)`
            Errno::ENOTTY => Ok(false),
            err => Err(Error::Sys(err))
        }
    }
}

pub fn unlink<P: ?Sized + NixPath>(path: &P) -> Result<()> {
    let res = try!(path.with_nix_path(|cstr| {
    unsafe {
        ffi::unlink(cstr.as_ptr())
    }
    }));
    from_ffi(res)
}

#[inline]
pub fn chroot<P: ?Sized + NixPath>(path: &P) -> Result<()> {
    let res = try!(path.with_nix_path(|cstr| {
        unsafe { ffi::chroot(cstr.as_ptr()) }
    }));

    if res != 0 {
        return Err(Error::Sys(Errno::last()));
    }

    Ok(())
}

#[cfg(any(target_os = "linux", target_os = "android"))]
mod linux {
    use sys::syscall::{syscall, SYSPIVOTROOT};
    use errno::Errno;
    use {Error, Result, NixPath};

    #[cfg(feature = "execvpe")]
    use std::ffi::CString;

    pub fn pivot_root<P1: ?Sized + NixPath, P2: ?Sized + NixPath>(
            new_root: &P1, put_old: &P2) -> Result<()> {
        let res = try!(try!(new_root.with_nix_path(|new_root| {
            put_old.with_nix_path(|put_old| {
                unsafe {
                    syscall(SYSPIVOTROOT, new_root.as_ptr(), put_old.as_ptr())
                }
            })
        })));

        if res != 0 {
            return Err(Error::Sys(Errno::last()));
        }

        Ok(())
    }

    #[inline]
    #[cfg(feature = "execvpe")]
    pub fn execvpe(filename: &CString, args: &[CString], env: &[CString]) -> Result<()> {
        use std::ptr;
        use libc::c_char;

        let mut args_p: Vec<*const c_char> = args.iter().map(|s| s.as_ptr()).collect();
        args_p.push(ptr::null());

        let mut env_p: Vec<*const c_char> = env.iter().map(|s| s.as_ptr()).collect();
        env_p.push(ptr::null());

        unsafe {
            super::ffi::execvpe(filename.as_ptr(), args_p.as_ptr(), env_p.as_ptr())
        };

        Err(Error::Sys(Errno::last()))
    }
}