| //! Linux auxv support, using libc. |
| //! |
| //! # Safety |
| //! |
| //! This uses raw pointers to locate and read the kernel-provided auxv array. |
| #![allow(unsafe_code)] |
| |
| use super::super::elf::*; |
| #[cfg(feature = "param")] |
| use crate::ffi::CStr; |
| #[cfg(feature = "runtime")] |
| use core::slice; |
| |
| // `getauxval` wasn't supported in glibc until 2.16. |
| weak!(fn getauxval(libc::c_ulong) -> *mut libc::c_void); |
| |
| #[cfg(feature = "param")] |
| #[inline] |
| pub(crate) fn page_size() -> usize { |
| unsafe { libc::sysconf(libc::_SC_PAGESIZE) as usize } |
| } |
| |
| #[cfg(feature = "param")] |
| #[inline] |
| pub(crate) fn clock_ticks_per_second() -> u64 { |
| unsafe { libc::sysconf(libc::_SC_CLK_TCK) as u64 } |
| } |
| |
| #[cfg(feature = "param")] |
| #[inline] |
| pub(crate) fn linux_hwcap() -> (usize, usize) { |
| if let Some(libc_getauxval) = getauxval.get() { |
| unsafe { |
| let hwcap = libc_getauxval(libc::AT_HWCAP) as usize; |
| let hwcap2 = libc_getauxval(libc::AT_HWCAP2) as usize; |
| (hwcap, hwcap2) |
| } |
| } else { |
| (0, 0) |
| } |
| } |
| |
| #[cfg(feature = "param")] |
| #[inline] |
| pub(crate) fn linux_execfn() -> &'static CStr { |
| if let Some(libc_getauxval) = getauxval.get() { |
| unsafe { CStr::from_ptr(libc_getauxval(libc::AT_EXECFN).cast()) } |
| } else { |
| cstr!("") |
| } |
| } |
| |
| #[cfg(feature = "runtime")] |
| #[inline] |
| pub(crate) fn exe_phdrs() -> (*const libc::c_void, usize) { |
| unsafe { |
| ( |
| libc::getauxval(libc::AT_PHDR) as *const libc::c_void, |
| libc::getauxval(libc::AT_PHNUM) as usize, |
| ) |
| } |
| } |
| |
| #[cfg(feature = "runtime")] |
| #[inline] |
| pub(in super::super) fn exe_phdrs_slice() -> &'static [Elf_Phdr] { |
| let (phdr, phnum) = exe_phdrs(); |
| |
| // SAFETY: We assume the `AT_PHDR` and `AT_PHNUM` values provided by the |
| // kernel form a valid slice. |
| unsafe { slice::from_raw_parts(phdr.cast(), phnum) } |
| } |
| |
| /// `AT_SYSINFO_EHDR` isn't present on all platforms in all configurations, |
| /// so if we don't see it, this function returns a null pointer. |
| #[inline] |
| pub(in super::super) fn sysinfo_ehdr() -> *const Elf_Ehdr { |
| if let Some(libc_getauxval) = getauxval.get() { |
| unsafe { libc_getauxval(linux_raw_sys::general::AT_SYSINFO_EHDR.into()) as *const Elf_Ehdr } |
| } else { |
| core::ptr::null() |
| } |
| } |