rand.rs.html -- source
Description: Source to the Rust file `libstd/sys/unix/rand.rs`.
Keywords: rust, rustlang, rust-lang

      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

    // Copyright 2013-2015 The Rust Project Developers. See the COPYRIGHT
    // file at the top-level directory of this distribution and at
    // http://rust-lang.org/COPYRIGHT.
    //
    // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
    // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
    // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
    // option. This file may not be copied, modified, or distributed
    // except according to those terms.

    use mem;
    use slice;

    pub fn hashmap_random_keys() -> (u64, u64) {
        let mut v = (0, 0);
        unsafe {
            let view = slice::from_raw_parts_mut(&mut v as *mut _ as *mut u8,
                                                 mem::size_of_val(&v));
            imp::fill_bytes(view);
        }
        return v
    }

    #[cfg(all(unix,
              not(target_os = "ios"),
              not(target_os = "openbsd"),
              not(target_os = "freebsd"),
              not(target_os = "fuchsia")))]
    mod imp {
        use fs::File;
        use io::Read;
        use libc;
        use sys::os::errno;

        #[cfg(any(target_os = "linux", target_os = "android"))]
        fn getrandom(buf: &mut [u8]) -> libc::c_long {
            unsafe {
                libc::syscall(libc::SYS_getrandom, buf.as_mut_ptr(), buf.len(), libc::GRND_NONBLOCK)
            }
        }

        #[cfg(not(any(target_os = "linux", target_os = "android")))]
        fn getrandom(_buf: &mut [u8]) -> libc::c_long { -1 }

        fn getrandom_fill_bytes(v: &mut [u8]) -> bool {
            let mut read = 0;
            while read < v.len() {
                let result = getrandom(&mut v[read..]);
                if result == -1 {
                    let err = errno() as libc::c_int;
                    if err == libc::EINTR {
                        continue;
                    } else if err == libc::EAGAIN {
                        return false
                    } else {
                        panic!("unexpected getrandom error: {}", err);
                    }
                } else {
                    read += result as usize;
                }
            }

            return true
        }

        #[cfg(any(target_os = "linux", target_os = "android"))]
        fn is_getrandom_available() -> bool {
            use io;
            use sync::atomic::{AtomicBool, Ordering};
            use sync::Once;

            static CHECKER: Once = Once::new();
            static AVAILABLE: AtomicBool = AtomicBool::new(false);

            CHECKER.call_once(|| {
                let mut buf: [u8; 0] = [];
                let result = getrandom(&mut buf);
                let available = if result == -1 {
                    let err = io::Error::last_os_error().raw_os_error();
                    err != Some(libc::ENOSYS)
                } else {
                    true
                };
                AVAILABLE.store(available, Ordering::Relaxed);
            });

            AVAILABLE.load(Ordering::Relaxed)
        }

        #[cfg(not(any(target_os = "linux", target_os = "android")))]
        fn is_getrandom_available() -> bool { false }

        pub fn fill_bytes(v: &mut [u8]) {
            // getrandom_fill_bytes here can fail if getrandom() returns EAGAIN,
            // meaning it would have blocked because the non-blocking pool (urandom)
            // has not initialized in the kernel yet due to a lack of entropy the
            // fallback we do here is to avoid blocking applications which could
            // depend on this call without ever knowing they do and don't have a
            // work around.  The PRNG of /dev/urandom will still be used but not
            // over a completely full entropy pool
            if is_getrandom_available() && getrandom_fill_bytes(v) {
                return
            }

            let mut file = File::open("/dev/urandom")
                .expect("failed to open /dev/urandom");
            file.read_exact(v).expect("failed to read /dev/urandom");
        }
    }

    #[cfg(target_os = "openbsd")]
    mod imp {
        use libc;
        use sys::os::errno;

        pub fn fill_bytes(v: &mut [u8]) {
            // getentropy(2) permits a maximum buffer size of 256 bytes
            for s in v.chunks_mut(256) {
                let ret = unsafe {
                    libc::getentropy(s.as_mut_ptr() as *mut libc::c_void, s.len())
                };
                if ret == -1 {
                    panic!("unexpected getentropy error: {}", errno());
                }
            }
        }
    }

    #[cfg(target_os = "ios")]
    mod imp {
        use io;
        use libc::{c_int, size_t};
        use ptr;

        enum SecRandom {}

        #[allow(non_upper_case_globals)]
        const kSecRandomDefault: *const SecRandom = ptr::null();

        extern {
            fn SecRandomCopyBytes(rnd: *const SecRandom,
                                  count: size_t,
                                  bytes: *mut u8) -> c_int;
        }

        pub fn fill_bytes(v: &mut [u8]) {
            let ret = unsafe {
                SecRandomCopyBytes(kSecRandomDefault,
                                   v.len(),
                                   v.as_mut_ptr())
            };
            if ret == -1 {
                panic!("couldn't generate random bytes: {}",
                       io::Error::last_os_error());
            }
        }
    }

    #[cfg(target_os = "freebsd")]
    mod imp {
        use libc;
        use ptr;

        pub fn fill_bytes(v: &mut [u8]) {
            let mib = [libc::CTL_KERN, libc::KERN_ARND];
            // kern.arandom permits a maximum buffer size of 256 bytes
            for s in v.chunks_mut(256) {
                let mut s_len = s.len();
                let ret = unsafe {
                    libc::sysctl(mib.as_ptr(), mib.len() as libc::c_uint,
                                 s.as_mut_ptr() as *mut _, &mut s_len,
                                 ptr::null(), 0)
                };
                if ret == -1 || s_len != s.len() {
                    panic!("kern.arandom sysctl failed! (returned {}, s.len() {}, oldlenp {})",
                           ret, s.len(), s_len);
                }
            }
        }
    }

    #[cfg(target_os = "fuchsia")]
    mod imp {
        #[link(name = "zircon")]
        extern {
            fn zx_cprng_draw(buffer: *mut u8, len: usize);
        }

        pub fn fill_bytes(v: &mut [u8]) {
            unsafe { zx_cprng_draw(v.as_mut_ptr(), v.len()) }
        }
    }

# Help

## Keyboard Shortcuts

`?`
  Show this help dialog
`S`
  Focus the search field
`↑`
  Move up in search results
`↓`
  Move down in search results
`↹`
  Switch tab
`⏎`
  Go to active search result
`+`
  Expand all sections
`-`
  Collapse all sections

## Search Tricks

Prefix searches with a type followed by a colon (e.g. `fn:`) to restrict the search to a given type.

Accepted types are: `fn`, `mod`, `struct`, `enum`, `trait`, `type`, `macro`, and `const`.

Search functions by type signature (e.g. `vec -> usize` or `* -> vec`)

Search multiple things at once by splitting your query with comma (e.g. `str,u8` or `String,struct:Vec,test`)