nix 0.24.3

Rust friendly bindings to *nix APIs
Documentation 
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

//! Configure the process resource limits.
use cfg_if::cfg_if;

use crate::errno::Errno;
use crate::Result;
pub use libc::rlim_t;
use std::mem;

cfg_if! {
    if #[cfg(all(target_os = "linux", any(target_env = "gnu", target_env = "uclibc")))]{
        use libc::{__rlimit_resource_t, rlimit};
    } else if #[cfg(any(
        target_os = "freebsd",
        target_os = "openbsd",
        target_os = "netbsd",
        target_os = "macos",
        target_os = "ios",
        target_os = "android",
        target_os = "dragonfly",
        all(target_os = "linux", not(target_env = "gnu"))
    ))]{
        use libc::{c_int, rlimit};
    }
}

libc_enum! {
    /// Types of process resources.
    ///
    /// The Resource enum is platform dependent. Check different platform
    /// manuals for more details. Some platform links have been provided for
    /// easier reference (non-exhaustive).
    ///
    /// * [Linux](https://man7.org/linux/man-pages/man2/getrlimit.2.html)
    /// * [FreeBSD](https://www.freebsd.org/cgi/man.cgi?query=setrlimit)
    /// * [NetBSD](https://man.netbsd.org/setrlimit.2)

    // linux-gnu uses u_int as resource enum, which is implemented in libc as
    // well.
    //
    // https://gcc.gnu.org/legacy-ml/gcc/2015-08/msg00441.html
    // https://github.com/rust-lang/libc/blob/master/src/unix/linux_like/linux/gnu/mod.rs
    #[cfg_attr(all(target_os = "linux", any(target_env = "gnu", target_env = "uclibc")), repr(u32))]
    #[cfg_attr(any(
            target_os = "freebsd",
            target_os = "openbsd",
            target_os = "netbsd",
            target_os = "macos",
            target_os = "ios",
            target_os = "android",
            target_os = "dragonfly",
            all(target_os = "linux", not(any(target_env = "gnu", target_env = "uclibc")))
        ), repr(i32))]
    #[non_exhaustive]
    pub enum Resource {
        #[cfg(not(any(target_os = "freebsd", target_os = "netbsd", target_os = "openbsd")))]
        #[cfg_attr(docsrs, doc(cfg(all())))]
        /// The maximum amount (in bytes) of virtual memory the process is
        /// allowed to map.
        RLIMIT_AS,
        /// The largest size (in bytes) core(5) file that may be created.
        RLIMIT_CORE,
        /// The maximum amount of cpu time (in seconds) to be used by each
        /// process.
        RLIMIT_CPU,
        /// The maximum size (in bytes) of the data segment for a process
        RLIMIT_DATA,
        /// The largest size (in bytes) file that may be created.
        RLIMIT_FSIZE,
        /// The maximum number of open files for this process.
        RLIMIT_NOFILE,
        /// The maximum size (in bytes) of the stack segment for a process.
        RLIMIT_STACK,

        #[cfg(target_os = "freebsd")]
        #[cfg_attr(docsrs, doc(cfg(all())))]
        /// The maximum number of kqueues this user id is allowed to create.
        RLIMIT_KQUEUES,

        #[cfg(any(target_os = "android", target_os = "linux"))]
        #[cfg_attr(docsrs, doc(cfg(all())))]
        /// A limit on the combined number of flock locks and fcntl leases that
        /// this process may establish.
        RLIMIT_LOCKS,

        #[cfg(any(
            target_os = "android",
            target_os = "freebsd",
            target_os = "openbsd",
            target_os = "linux",
            target_os = "netbsd"
        ))]
        #[cfg_attr(docsrs, doc(cfg(all())))]
        /// The maximum size (in bytes) which a process may lock into memory
        /// using the mlock(2) system call.
        RLIMIT_MEMLOCK,

        #[cfg(any(target_os = "android", target_os = "linux"))]
        #[cfg_attr(docsrs, doc(cfg(all())))]
        /// A limit on the number of bytes that can be allocated for POSIX
        /// message queues  for  the  real  user  ID  of  the  calling process.
        RLIMIT_MSGQUEUE,

        #[cfg(any(target_os = "android", target_os = "linux"))]
        #[cfg_attr(docsrs, doc(cfg(all())))]
        /// A ceiling to which the process's nice value can be raised using
        /// setpriority or nice.
        RLIMIT_NICE,

        #[cfg(any(
            target_os = "android",
            target_os = "freebsd",
            target_os = "netbsd",
            target_os = "openbsd",
            target_os = "linux",
        ))]
        #[cfg_attr(docsrs, doc(cfg(all())))]
        /// The maximum number of simultaneous processes for this user id.
        RLIMIT_NPROC,

        #[cfg(target_os = "freebsd")]
        #[cfg_attr(docsrs, doc(cfg(all())))]
        /// The maximum number of pseudo-terminals this user id is allowed to
        /// create.
        RLIMIT_NPTS,

        #[cfg(any(target_os = "android",
            target_os = "freebsd",
            target_os = "netbsd",
            target_os = "openbsd",
            target_os = "linux",
        ))]
        #[cfg_attr(docsrs, doc(cfg(all())))]
        /// When there is memory pressure and swap is available, prioritize
        /// eviction of a process' resident pages beyond this amount (in bytes).
        RLIMIT_RSS,

        #[cfg(any(target_os = "android", target_os = "linux"))]
        #[cfg_attr(docsrs, doc(cfg(all())))]
        /// A ceiling on the real-time priority that may be set for this process
        /// using sched_setscheduler and  sched_set‐ param.
        RLIMIT_RTPRIO,

        #[cfg(any(target_os = "linux"))]
        #[cfg_attr(docsrs, doc(cfg(all())))]
        /// A limit (in microseconds) on the amount of CPU time that a process
        /// scheduled under a real-time scheduling policy may con‐ sume without
        /// making a blocking system call.
        RLIMIT_RTTIME,

        #[cfg(any(target_os = "android", target_os = "linux"))]
        #[cfg_attr(docsrs, doc(cfg(all())))]
        /// A limit on the number of signals that may be queued for the real
        /// user ID of the  calling  process.
        RLIMIT_SIGPENDING,

        #[cfg(any(target_os = "freebsd", target_os = "dragonfly"))]
        #[cfg_attr(docsrs, doc(cfg(all())))]
        /// The maximum size (in bytes) of socket buffer usage for this user.
        RLIMIT_SBSIZE,

        #[cfg(target_os = "freebsd")]
        #[cfg_attr(docsrs, doc(cfg(all())))]
        /// The maximum size (in bytes) of the swap space that may be reserved
        /// or used by all of this user id's processes.
        RLIMIT_SWAP,

        #[cfg(target_os = "freebsd")]
        #[cfg_attr(docsrs, doc(cfg(all())))]
        /// An alias for RLIMIT_AS.
        RLIMIT_VMEM,
    }
}

/// Get the current processes resource limits
///
/// The special value `RLIM_INFINITY` indicates that no limit will be
/// enforced.
///
/// # Parameters
///
/// * `resource`: The [`Resource`] that we want to get the limits of.
///
/// # Examples
///
/// ```
/// # use nix::sys::resource::{getrlimit, Resource};
///
/// let (soft_limit, hard_limit) = getrlimit(Resource::RLIMIT_NOFILE).unwrap();
/// println!("current soft_limit: {}", soft_limit);
/// println!("current hard_limit: {}", hard_limit);
/// ```
///
/// # References
///
/// [getrlimit(2)](https://pubs.opengroup.org/onlinepubs/9699919799/functions/getrlimit.html#tag_16_215)
///
/// [`Resource`]: enum.Resource.html
pub fn getrlimit(resource: Resource) -> Result<(rlim_t, rlim_t)> {
    let mut old_rlim = mem::MaybeUninit::<rlimit>::uninit();

    cfg_if! {
        if #[cfg(all(target_os = "linux", any(target_env = "gnu", target_env = "uclibc")))]{
            let res = unsafe { libc::getrlimit(resource as __rlimit_resource_t, old_rlim.as_mut_ptr()) };
        } else {
            let res = unsafe { libc::getrlimit(resource as c_int, old_rlim.as_mut_ptr()) };
        }
    }

    Errno::result(res).map(|_| {
        let rlimit { rlim_cur, rlim_max } = unsafe { old_rlim.assume_init() };
        (rlim_cur, rlim_max)
    })
}

/// Set the current processes resource limits
///
/// # Parameters
///
/// * `resource`: The [`Resource`] that we want to set the limits of.
/// * `soft_limit`: The value that the kernel enforces for the corresponding
///   resource.
/// * `hard_limit`: The ceiling for the soft limit. Must be lower or equal to
///   the current hard limit for non-root users.
///
/// The special value `RLIM_INFINITY` indicates that no limit will be
/// enforced.
///
/// # Examples
///
/// ```
/// # use nix::sys::resource::{setrlimit, Resource};
///
/// let soft_limit = 512;
/// let hard_limit = 1024;
/// setrlimit(Resource::RLIMIT_NOFILE, soft_limit, hard_limit).unwrap();
/// ```
///
/// # References
///
/// [setrlimit(2)](https://pubs.opengroup.org/onlinepubs/9699919799/functions/getrlimit.html#tag_16_215)
///
/// [`Resource`]: enum.Resource.html
///
/// Note: `setrlimit` provides a safe wrapper to libc's `setrlimit`.
pub fn setrlimit(
    resource: Resource,
    soft_limit: rlim_t,
    hard_limit: rlim_t,
) -> Result<()> {
    let new_rlim = rlimit {
        rlim_cur: soft_limit,
        rlim_max: hard_limit,
    };
    cfg_if! {
        if #[cfg(all(target_os = "linux", any(target_env = "gnu", target_env = "uclibc")))]{
            let res = unsafe { libc::setrlimit(resource as __rlimit_resource_t, &new_rlim as *const rlimit) };
        }else{
            let res = unsafe { libc::setrlimit(resource as c_int, &new_rlim as *const rlimit) };
        }
    }

    Errno::result(res).map(drop)
}