ethrex_common/
fd_limit.rs

1// Copyright 2016-2020 Parity Technologies (UK) Ltd.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15/// Outcome of raising file descriptor resource limit
16pub enum Outcome {
17    /// Limit was raised successfully
18    LimitRaised {
19        /// Previous limit (likely soft limit)
20        from: u64,
21        /// New limit (likely hard limit)
22        to: u64,
23    },
24    /// Raising limit is not supported on this platform
25    Unsupported,
26}
27
28/// Errors that happen when trying to raise file descriptor resource limit
29#[derive(Debug, thiserror::Error)]
30pub enum Error {
31    /// Failed to call sysctl to get max supported value configured in sysctl
32    #[error("Failed to call sysctl to get max supported value configured in sysctl: {0}")]
33    #[cfg(any(target_os = "macos", target_os = "ios"))]
34    FailedToCallSysctl(std::io::Error),
35    /// Failed to get current limit
36    #[error("Failed to get current limit: {0}")]
37    FailedToGetLimit(std::io::Error),
38    /// Failed to set new limit
39    #[error("Failed to set new limit ({from}->{to}): {error}")]
40    FailedToSetLimit {
41        /// Current limit
42        from: u64,
43        /// New desired limit
44        to: u64,
45        /// Low level OS error
46        error: std::io::Error,
47    },
48}
49
50/// Raise the soft open file descriptor resource limit to the smaller of the
51/// kernel limit and the hard resource limit.
52///
53/// darwin_fd_limit exists to work around an issue where launchctl on Mac OS X
54/// defaults the rlimit maxfiles to 256/unlimited. The default soft limit of 256
55/// ends up being far too low for our multithreaded scheduler testing, depending
56/// on the number of cores available.
57#[cfg(any(target_os = "macos", target_os = "ios"))]
58#[allow(clippy::useless_conversion, non_camel_case_types)]
59pub fn raise_fd_limit() -> Result<Outcome, Error> {
60    use std::cmp;
61    use std::io;
62    use std::mem::size_of_val;
63    use std::ptr::null_mut;
64
65    unsafe {
66        static CTL_KERN: libc::c_int = 1;
67        static KERN_MAXFILESPERPROC: libc::c_int = 29;
68
69        // The strategy here is to fetch the current resource limits, read the
70        // kern.maxfilesperproc sysctl value, and bump the soft resource limit for
71        // maxfiles up to the sysctl value.
72
73        // Fetch the kern.maxfilesperproc value
74        let mut mib: [libc::c_int; 2] = [CTL_KERN, KERN_MAXFILESPERPROC];
75        let mut maxfiles: libc::c_int = 0;
76        let mut size: libc::size_t = size_of_val(&maxfiles) as libc::size_t;
77        if libc::sysctl(
78            &mut mib[0],
79            2,
80            &mut maxfiles as *mut _ as *mut _,
81            &mut size,
82            null_mut(),
83            0,
84        ) != 0
85        {
86            return Err(Error::FailedToCallSysctl(io::Error::last_os_error()));
87        }
88
89        // Fetch the current resource limits
90        let mut rlim = libc::rlimit {
91            rlim_cur: 0,
92            rlim_max: 0,
93        };
94        if libc::getrlimit(libc::RLIMIT_NOFILE, &mut rlim) != 0 {
95            return Err(Error::FailedToGetLimit(io::Error::last_os_error()));
96        }
97
98        let old_value = rlim.rlim_cur;
99
100        // Bump the soft limit to the smaller of kern.maxfilesperproc and the hard
101        // limit
102        rlim.rlim_cur = cmp::min(maxfiles as libc::rlim_t, rlim.rlim_max);
103
104        // Set our newly-increased resource limit
105        if libc::setrlimit(libc::RLIMIT_NOFILE, &rlim) != 0 {
106            return Err(Error::FailedToSetLimit {
107                from: old_value.into(),
108                to: rlim.rlim_cur.into(),
109                error: io::Error::last_os_error(),
110            });
111        }
112
113        Ok(Outcome::LimitRaised {
114            from: old_value.into(),
115            to: rlim.rlim_cur.into(),
116        })
117    }
118}
119
120/// Raise the soft open file descriptor resource limit to the hard resource
121/// limit.
122#[cfg(target_os = "linux")]
123#[allow(clippy::useless_conversion, non_camel_case_types)]
124pub fn raise_fd_limit() -> Result<Outcome, Error> {
125    use std::io;
126
127    unsafe {
128        // Fetch the current resource limits
129        let mut rlim = libc::rlimit {
130            rlim_cur: 0,
131            rlim_max: 0,
132        };
133        if libc::getrlimit(libc::RLIMIT_NOFILE, &mut rlim) != 0 {
134            return Err(Error::FailedToGetLimit(io::Error::last_os_error()));
135        }
136
137        let old_value = rlim.rlim_cur;
138
139        // Set soft limit to hard imit
140        rlim.rlim_cur = rlim.rlim_max;
141
142        // Set our newly-increased resource limit
143        if libc::setrlimit(libc::RLIMIT_NOFILE, &rlim) != 0 {
144            return Err(Error::FailedToSetLimit {
145                from: old_value.into(),
146                to: rlim.rlim_cur.into(),
147                error: io::Error::last_os_error(),
148            });
149        }
150
151        Ok(Outcome::LimitRaised {
152            from: old_value.into(),
153            to: rlim.rlim_cur.into(),
154        })
155    }
156}
157
158/// Does nothing on unsupported platform
159#[cfg(not(any(target_os = "macos", target_os = "ios", target_os = "linux")))]
160pub fn raise_fd_limit() -> Result<Outcome, Error> {
161    Ok(Outcome::Unsupported)
162}
ethrex_common/fd_limit.rs

ethrex_common/
fd_limit.rs
