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
|
// Copyright 2017 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//! Small system utility modules for usage by other modules.
extern crate data_model;
extern crate libc;
extern crate syscall_defines;
#[allow(unused_imports)]
#[macro_use]
extern crate poll_token_derive;
#[macro_use]
pub mod handle_eintr;
#[macro_use]
pub mod ioctl;
#[macro_use]
pub mod syslog;
mod mmap;
mod shm;
mod eventfd;
mod errno;
mod guest_address;
mod guest_memory;
mod poll;
mod struct_util;
mod tempdir;
mod terminal;
pub mod signal;
mod fork;
mod signalfd;
mod sock_ctrl_msg;
mod passwd;
pub use mmap::*;
pub use shm::*;
pub use eventfd::*;
pub use errno::{Error, Result};
use errno::errno_result;
pub use guest_address::*;
pub use guest_memory::*;
pub use poll::*;
pub use struct_util::*;
pub use tempdir::*;
pub use terminal::*;
pub use signal::*;
pub use fork::*;
pub use signalfd::*;
pub use ioctl::*;
pub use sock_ctrl_msg::*;
pub use passwd::*;
pub use poll_token_derive::*;
pub use mmap::Error as MmapError;
pub use guest_memory::Error as GuestMemoryError;
pub use signalfd::Error as SignalFdError;
use std::ffi::CStr;
use std::os::unix::io::AsRawFd;
use std::ptr;
use libc::{kill, syscall, sysconf, waitpid, c_long, pid_t, uid_t, gid_t, _SC_PAGESIZE,
SIGKILL, WNOHANG};
use syscall_defines::linux::LinuxSyscall::SYS_getpid;
/// Safe wrapper for `sysconf(_SC_PAGESIZE)`.
#[inline(always)]
pub fn pagesize() -> usize {
// Trivially safe
unsafe { sysconf(_SC_PAGESIZE) as usize }
}
/// This bypasses `libc`'s caching `getpid(2)` wrapper which can be invalid if a raw clone was used
/// elsewhere.
#[inline(always)]
pub fn getpid() -> pid_t {
// Safe because this syscall can never fail and we give it a valid syscall number.
unsafe { syscall(SYS_getpid as c_long) as pid_t }
}
/// Safe wrapper for `geteuid(2)`.
#[inline(always)]
pub fn geteuid() -> uid_t {
// trivially safe
unsafe { libc::geteuid() }
}
/// Safe wrapper for `getegid(2)`.
#[inline(always)]
pub fn getegid() -> gid_t {
// trivially safe
unsafe { libc::getegid() }
}
/// Safe wrapper for chown(2).
#[inline(always)]
pub fn chown(path: &CStr, uid: uid_t, gid: gid_t) -> Result<()> {
// Safe since we pass in a valid string pointer and check the return value.
let ret = unsafe { libc::chown(path.as_ptr(), uid, gid) };
if ret < 0 {
errno_result()
} else {
Ok(())
}
}
/// The operation to perform with `flock`.
pub enum FlockOperation {
LockShared,
LockExclusive,
Unlock,
}
/// Safe wrapper for flock(2) with the operation `op` and optionally `nonblocking`. The lock will be
/// dropped automatically when `file` is dropped.
#[inline(always)]
pub fn flock(file: &AsRawFd, op: FlockOperation, nonblocking: bool) -> Result<()> {
let mut operation = match op {
FlockOperation::LockShared => libc::LOCK_SH,
FlockOperation::LockExclusive => libc::LOCK_EX,
FlockOperation::Unlock => libc::LOCK_UN,
};
if nonblocking {
operation |= libc::LOCK_NB;
}
// Safe since we pass in a valid fd and flock operation, and check the return value.
let ret = unsafe { libc::flock(file.as_raw_fd(), operation) };
if ret < 0 {
errno_result()
} else {
Ok(())
}
}
/// Reaps a child process that has terminated.
///
/// Returns `Ok(pid)` where `pid` is the process that was reaped or `Ok(0)` if none of the children
/// have terminated. An `Error` is with `errno == ECHILD` if there are no children left to reap.
///
/// # Examples
///
/// Reaps all child processes until there are no terminated children to reap.
///
/// ```
/// # extern crate libc;
/// # extern crate sys_util;
/// fn reap_children() {
/// loop {
/// match sys_util::reap_child() {
/// Ok(0) => println!("no children ready to reap"),
/// Ok(pid) => {
/// println!("reaped {}", pid);
/// continue
/// },
/// Err(e) if e.errno() == libc::ECHILD => println!("no children left"),
/// Err(e) => println!("error reaping children: {:?}", e),
/// }
/// break
/// }
/// }
/// ```
pub fn reap_child() -> Result<pid_t> {
// Safe because we pass in no memory, prevent blocking with WNOHANG, and check for error.
let ret = unsafe { waitpid(-1, ptr::null_mut(), WNOHANG) };
if ret == -1 {
errno_result()
} else {
Ok(ret)
}
}
/// Kill all processes in the current process group.
///
/// On success, this kills all processes in the current process group, including the current
/// process, meaning this will not return. This is equivalent to a call to `kill(0, SIGKILL)`.
pub fn kill_process_group() -> Result<()> {
let ret = unsafe { kill(0, SIGKILL) };
if ret == -1 {
errno_result()
} else {
// Kill succeeded, so this process never reaches here.
unreachable!();
}
}
|