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
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
use io::{self, Error, ErrorKind};
use libc::{self, c_int, gid_t, pid_t, uid_t};
use ptr;
use sys::cvt;
use sys::process::process_common::*;
use sys;
impl Command {
pub fn spawn(&mut self, default: Stdio, needs_stdin: bool)
-> io::Result<(Process, StdioPipes)> {
const CLOEXEC_MSG_FOOTER: &'static [u8] = b"NOEX";
let envp = self.capture_env();
if self.saw_nul() {
return Err(io::Error::new(ErrorKind::InvalidInput,
"nul byte found in provided data"));
}
let (ours, theirs) = self.setup_io(default, needs_stdin)?;
if let Some(ret) = self.posix_spawn(&theirs, envp.as_ref())? {
return Ok((ret, ours))
}
let (input, output) = sys::pipe::anon_pipe()?;
let result = unsafe {
let _env_lock = sys::os::env_lock();
cvt(libc::fork())?
};
let pid = unsafe {
match result {
0 => {
drop(input);
let err = self.do_exec(theirs, envp.as_ref());
let errno = err.raw_os_error().unwrap_or(libc::EINVAL) as u32;
let bytes = [
(errno >> 24) as u8,
(errno >> 16) as u8,
(errno >> 8) as u8,
(errno >> 0) as u8,
CLOEXEC_MSG_FOOTER[0], CLOEXEC_MSG_FOOTER[1],
CLOEXEC_MSG_FOOTER[2], CLOEXEC_MSG_FOOTER[3]
];
assert!(output.write(&bytes).is_ok());
libc::_exit(1)
}
n => n,
}
};
let mut p = Process { pid: pid, status: None };
drop(output);
let mut bytes = [0; 8];
loop {
match input.read(&mut bytes) {
Ok(0) => return Ok((p, ours)),
Ok(8) => {
assert!(combine(CLOEXEC_MSG_FOOTER) == combine(&bytes[4.. 8]),
"Validation on the CLOEXEC pipe failed: {:?}", bytes);
let errno = combine(&bytes[0.. 4]);
assert!(p.wait().is_ok(),
"wait() should either return Ok or panic");
return Err(Error::from_raw_os_error(errno))
}
Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
Err(e) => {
assert!(p.wait().is_ok(),
"wait() should either return Ok or panic");
panic!("the CLOEXEC pipe failed: {:?}", e)
},
Ok(..) => {
assert!(p.wait().is_ok(),
"wait() should either return Ok or panic");
panic!("short read on the CLOEXEC pipe")
}
}
}
fn combine(arr: &[u8]) -> i32 {
let a = arr[0] as u32;
let b = arr[1] as u32;
let c = arr[2] as u32;
let d = arr[3] as u32;
((a << 24) | (b << 16) | (c << 8) | (d << 0)) as i32
}
}
pub fn exec(&mut self, default: Stdio) -> io::Error {
let envp = self.capture_env();
if self.saw_nul() {
return io::Error::new(ErrorKind::InvalidInput,
"nul byte found in provided data")
}
match self.setup_io(default, true) {
Ok((_, theirs)) => {
unsafe {
let _lock = sys::os::env_lock();
self.do_exec(theirs, envp.as_ref())
}
}
Err(e) => e,
}
}
unsafe fn do_exec(
&mut self,
stdio: ChildPipes,
maybe_envp: Option<&CStringArray>
) -> io::Error {
use sys::{self, cvt_r};
macro_rules! t {
($e:expr) => (match $e {
Ok(e) => e,
Err(e) => return e,
})
}
if let Some(fd) = stdio.stdin.fd() {
t!(cvt_r(|| libc::dup2(fd, libc::STDIN_FILENO)));
}
if let Some(fd) = stdio.stdout.fd() {
t!(cvt_r(|| libc::dup2(fd, libc::STDOUT_FILENO)));
}
if let Some(fd) = stdio.stderr.fd() {
t!(cvt_r(|| libc::dup2(fd, libc::STDERR_FILENO)));
}
if cfg!(not(any(target_os = "l4re"))) {
if let Some(u) = self.get_gid() {
t!(cvt(libc::setgid(u as gid_t)));
}
if let Some(u) = self.get_uid() {
let _ = libc::setgroups(0, ptr::null());
t!(cvt(libc::setuid(u as uid_t)));
}
}
if let Some(ref cwd) = *self.get_cwd() {
t!(cvt(libc::chdir(cwd.as_ptr())));
}
#[cfg(not(any(target_os = "emscripten")))]
{
use mem;
let mut set: libc::sigset_t = mem::uninitialized();
if cfg!(target_os = "android") {
libc::memset(&mut set as *mut _ as *mut _,
0,
mem::size_of::<libc::sigset_t>());
} else {
t!(cvt(libc::sigemptyset(&mut set)));
}
t!(cvt(libc::pthread_sigmask(libc::SIG_SETMASK, &set,
ptr::null_mut())));
let ret = sys::signal(libc::SIGPIPE, libc::SIG_DFL);
if ret == libc::SIG_ERR {
return io::Error::last_os_error()
}
}
for callback in self.get_closures().iter_mut() {
t!(callback());
}
let mut _reset = None;
if let Some(envp) = maybe_envp {
struct Reset(*const *const libc::c_char);
impl Drop for Reset {
fn drop(&mut self) {
unsafe {
*sys::os::environ() = self.0;
}
}
}
_reset = Some(Reset(*sys::os::environ()));
*sys::os::environ() = envp.as_ptr();
}
libc::execvp(self.get_argv()[0], self.get_argv().as_ptr());
io::Error::last_os_error()
}
#[cfg(not(any(target_os = "macos", target_os = "freebsd",
all(target_os = "linux", target_env = "gnu"))))]
fn posix_spawn(&mut self, _: &ChildPipes, _: Option<&CStringArray>)
-> io::Result<Option<Process>>
{
Ok(None)
}
#[cfg(any(target_os = "macos", target_os = "freebsd",
all(target_os = "linux", target_env = "gnu")))]
fn posix_spawn(&mut self, stdio: &ChildPipes, envp: Option<&CStringArray>)
-> io::Result<Option<Process>>
{
use mem;
use sys;
if self.get_cwd().is_some() ||
self.get_gid().is_some() ||
self.get_uid().is_some() ||
self.env_saw_path() ||
self.get_closures().len() != 0 {
return Ok(None)
}
#[cfg(all(target_os = "linux", target_env = "gnu"))]
{
if let Some(version) = sys::os::glibc_version() {
if version < (2, 24) {
return Ok(None)
}
} else {
return Ok(None)
}
}
let mut p = Process { pid: 0, status: None };
struct PosixSpawnFileActions(libc::posix_spawn_file_actions_t);
impl Drop for PosixSpawnFileActions {
fn drop(&mut self) {
unsafe {
libc::posix_spawn_file_actions_destroy(&mut self.0);
}
}
}
struct PosixSpawnattr(libc::posix_spawnattr_t);
impl Drop for PosixSpawnattr {
fn drop(&mut self) {
unsafe {
libc::posix_spawnattr_destroy(&mut self.0);
}
}
}
unsafe {
let mut file_actions = PosixSpawnFileActions(mem::uninitialized());
let mut attrs = PosixSpawnattr(mem::uninitialized());
libc::posix_spawnattr_init(&mut attrs.0);
libc::posix_spawn_file_actions_init(&mut file_actions.0);
if let Some(fd) = stdio.stdin.fd() {
cvt(libc::posix_spawn_file_actions_adddup2(&mut file_actions.0,
fd,
libc::STDIN_FILENO))?;
}
if let Some(fd) = stdio.stdout.fd() {
cvt(libc::posix_spawn_file_actions_adddup2(&mut file_actions.0,
fd,
libc::STDOUT_FILENO))?;
}
if let Some(fd) = stdio.stderr.fd() {
cvt(libc::posix_spawn_file_actions_adddup2(&mut file_actions.0,
fd,
libc::STDERR_FILENO))?;
}
let mut set: libc::sigset_t = mem::uninitialized();
cvt(libc::sigemptyset(&mut set))?;
cvt(libc::posix_spawnattr_setsigmask(&mut attrs.0,
&set))?;
cvt(libc::sigaddset(&mut set, libc::SIGPIPE))?;
cvt(libc::posix_spawnattr_setsigdefault(&mut attrs.0,
&set))?;
let flags = libc::POSIX_SPAWN_SETSIGDEF |
libc::POSIX_SPAWN_SETSIGMASK;
cvt(libc::posix_spawnattr_setflags(&mut attrs.0, flags as _))?;
let _env_lock = sys::os::env_lock();
let envp = envp.map(|c| c.as_ptr())
.unwrap_or_else(|| *sys::os::environ() as *const _);
let ret = libc::posix_spawnp(
&mut p.pid,
self.get_argv()[0],
&file_actions.0,
&attrs.0,
self.get_argv().as_ptr() as *const _,
envp as *const _,
);
if ret == 0 {
Ok(Some(p))
} else {
Err(io::Error::from_raw_os_error(ret))
}
}
}
}
pub struct Process {
pid: pid_t,
status: Option<ExitStatus>,
}
impl Process {
pub fn id(&self) -> u32 {
self.pid as u32
}
pub fn kill(&mut self) -> io::Result<()> {
if self.status.is_some() {
Err(Error::new(ErrorKind::InvalidInput,
"invalid argument: can't kill an exited process"))
} else {
cvt(unsafe { libc::kill(self.pid, libc::SIGKILL) }).map(|_| ())
}
}
pub fn wait(&mut self) -> io::Result<ExitStatus> {
use sys::cvt_r;
if let Some(status) = self.status {
return Ok(status)
}
let mut status = 0 as c_int;
cvt_r(|| unsafe { libc::waitpid(self.pid, &mut status, 0) })?;
self.status = Some(ExitStatus::new(status));
Ok(ExitStatus::new(status))
}
pub fn try_wait(&mut self) -> io::Result<Option<ExitStatus>> {
if let Some(status) = self.status {
return Ok(Some(status))
}
let mut status = 0 as c_int;
let pid = cvt(unsafe {
libc::waitpid(self.pid, &mut status, libc::WNOHANG)
})?;
if pid == 0 {
Ok(None)
} else {
self.status = Some(ExitStatus::new(status));
Ok(Some(ExitStatus::new(status)))
}
}
}