Grcov report - linux

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// Copyright 2018 Developers of the Rand project.

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//

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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or

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// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license

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// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your

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// option. This file may not be copied, modified, or distributed

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// except according to those terms.

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//! Implementation for Linux / Android

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use crate::{

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    util::LazyBool,

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    util_libc::{last_os_error, sys_fill_exact},

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    {use_file, Error},

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};

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use core::mem::MaybeUninit;

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pub fn getrandom_inner(dest: &mut [MaybeUninit<u8>]) -> Result<(), Error> {

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    // getrandom(2) was introduced in Linux 3.17

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    static HAS_GETRANDOM: LazyBool = LazyBool::new();

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    if HAS_GETRANDOM.unsync_init(is_getrandom_available) {

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        sys_fill_exact(dest, |buf| unsafe {

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            getrandom(buf.as_mut_ptr() as *mut libc::c_void, buf.len(), 0)

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})

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    } else {

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        use_file::getrandom_inner(dest)

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fn is_getrandom_available() -> bool {

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    let res = unsafe { getrandom(core::ptr::null_mut(), 0, libc::GRND_NONBLOCK) };

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    if res < 0 {

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        match last_os_error().raw_os_error() {

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            Some(libc::ENOSYS) => false, // No kernel support

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            Some(libc::EPERM) => false,  // Blocked by seccomp

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            _ => true,

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    } else {

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        true

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2

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unsafe fn getrandom(

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    buf: *mut libc::c_void,

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    buflen: libc::size_t,

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    flags: libc::c_uint,

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) -> libc::ssize_t {

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    libc::syscall(libc::SYS_getrandom, buf, buflen, flags) as libc::ssize_t

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