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
use std::fs::File;
use std::mem;
use std::os::raw::c_int;
use std::os::unix::io::AsRawFd;
use std::os::unix::io::FromRawFd;
use std::os::unix::io::RawFd;
use std::result;
use libc::c_void;
use libc::read;
use libc::signalfd;
use libc::signalfd_siginfo;
use libc::EAGAIN;
use libc::SFD_CLOEXEC;
use libc::SFD_NONBLOCK;
use log::error;
use remain::sorted;
use thiserror::Error;
use super::signal;
use super::Error as ErrnoError;
use super::RawDescriptor;
use crate::descriptor::AsRawDescriptor;
#[sorted]
#[derive(Error, Debug)]
pub enum Error {
#[error("failed to block the signal when creating signalfd: {0}")]
CreateBlockSignal(signal::Error),
#[error("failed to create a new signalfd: {0}")]
CreateSignalFd(ErrnoError),
#[error("failed to construct sigset when creating signalfd: {0}")]
CreateSigset(ErrnoError),
#[error("signalfd failed to return a full siginfo struct, read only {0} bytes")]
SignalFdPartialRead(usize),
#[error("unable to read from signalfd: {0}")]
SignalFdRead(ErrnoError),
}
pub type Result<T> = result::Result<T, Error>;
pub struct SignalFd {
signalfd: File,
signal: c_int,
}
impl SignalFd {
pub fn new(signal: c_int) -> Result<SignalFd> {
let sigset = signal::create_sigset(&[signal]).map_err(Error::CreateSigset)?;
let fd = unsafe { signalfd(-1, &sigset, SFD_CLOEXEC | SFD_NONBLOCK) };
if fd < 0 {
return Err(Error::CreateSignalFd(ErrnoError::last()));
}
signal::block_signal(signal).map_err(Error::CreateBlockSignal)?;
unsafe {
Ok(SignalFd {
signalfd: File::from_raw_fd(fd),
signal,
})
}
}
pub fn read(&self) -> Result<Option<signalfd_siginfo>> {
let mut siginfo: signalfd_siginfo = unsafe { mem::zeroed() };
let siginfo_size = mem::size_of::<signalfd_siginfo>();
let ret = unsafe {
read(
self.signalfd.as_raw_fd(),
&mut siginfo as *mut signalfd_siginfo as *mut c_void,
siginfo_size,
)
};
if ret < 0 {
let err = ErrnoError::last();
if err.errno() == EAGAIN {
Ok(None)
} else {
Err(Error::SignalFdRead(err))
}
} else if ret == (siginfo_size as isize) {
Ok(Some(siginfo))
} else {
Err(Error::SignalFdPartialRead(ret as usize))
}
}
}
impl AsRawFd for SignalFd {
fn as_raw_fd(&self) -> RawFd {
self.signalfd.as_raw_fd()
}
}
impl AsRawDescriptor for SignalFd {
fn as_raw_descriptor(&self) -> RawDescriptor {
self.signalfd.as_raw_descriptor()
}
}
impl Drop for SignalFd {
fn drop(&mut self) {
let res = signal::unblock_signal(self.signal);
if let Err(e) = res {
error!("signalfd failed to unblock signal {}: {}", self.signal, e);
}
}
}
#[cfg(test)]
mod tests {
use std::mem;
use std::ptr::null;
use libc::pthread_sigmask;
use libc::raise;
use libc::sigismember;
use libc::sigset_t;
use super::super::signal::SIGRTMIN;
use super::*;
#[test]
fn new() {
SignalFd::new(SIGRTMIN()).unwrap();
}
#[test]
fn read() {
let sigid = SIGRTMIN() + 1;
let sigrt_fd = SignalFd::new(sigid).unwrap();
let ret = unsafe { raise(sigid) };
assert_eq!(ret, 0);
let siginfo = sigrt_fd.read().unwrap().unwrap();
assert_eq!(siginfo.ssi_signo, sigid as u32);
}
#[test]
fn drop() {
let sigid = SIGRTMIN() + 2;
let sigrt_fd = SignalFd::new(sigid).unwrap();
unsafe {
let mut sigset: sigset_t = mem::zeroed();
pthread_sigmask(0, null(), &mut sigset as *mut sigset_t);
assert_eq!(sigismember(&sigset, sigid), 1);
}
mem::drop(sigrt_fd);
unsafe {
let mut sigset: sigset_t = mem::zeroed();
pthread_sigmask(0, null(), &mut sigset as *mut sigset_t);
assert_eq!(sigismember(&sigset, sigid), 0);
}
}
}