diff options
Diffstat (limited to 'third_party/rust/getrandom/src/linux_android_with_fallback.rs')
-rw-r--r-- | third_party/rust/getrandom/src/linux_android_with_fallback.rs | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/third_party/rust/getrandom/src/linux_android_with_fallback.rs b/third_party/rust/getrandom/src/linux_android_with_fallback.rs new file mode 100644 index 0000000000..0f5ea8a992 --- /dev/null +++ b/third_party/rust/getrandom/src/linux_android_with_fallback.rs @@ -0,0 +1,33 @@ +//! Implementation for Linux / Android with `/dev/urandom` fallback +use crate::{ + lazy::LazyBool, + util_libc::{getrandom_syscall, last_os_error, sys_fill_exact}, + {use_file, Error}, +}; +use core::mem::MaybeUninit; + +pub fn getrandom_inner(dest: &mut [MaybeUninit<u8>]) -> Result<(), Error> { + // getrandom(2) was introduced in Linux 3.17 + static HAS_GETRANDOM: LazyBool = LazyBool::new(); + if HAS_GETRANDOM.unsync_init(is_getrandom_available) { + sys_fill_exact(dest, getrandom_syscall) + } else { + use_file::getrandom_inner(dest) + } +} + +fn is_getrandom_available() -> bool { + if getrandom_syscall(&mut []) < 0 { + match last_os_error().raw_os_error() { + Some(libc::ENOSYS) => false, // No kernel support + // The fallback on EPERM is intentionally not done on Android since this workaround + // seems to be needed only for specific Linux-based products that aren't based + // on Android. See https://github.com/rust-random/getrandom/issues/229. + #[cfg(target_os = "linux")] + Some(libc::EPERM) => false, // Blocked by seccomp + _ => true, + } + } else { + true + } +} |