rust/pv: Replace libc wherever possible

Replace all libc references to rust-std references if available.
This eliminates the need to include libc in the pv crate.
However, pv_base still refers to libc::ioctl and libc::ENOTTY.

Reviewed-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>

rust/pv/src/verify/helper.rs

@@ -7,7 +7,6 @@ use crate::misc::read_crls;
 use crate::HkdVerifyErrorType::*;
 use crate::{Error, Result};
 use curl::easy::{Easy2, Handler, WriteError};
-use libc::c_int;
 use log::debug;
 use openssl::{
     asn1::{Asn1Time, Asn1TimeRef},
@@ -26,9 +25,7 @@ use openssl_extensions::{
     akid::{AkidCheckResult, AkidExtension},
     crl::X509StoreExtension,
 };
-use std::cmp::Ordering;
-use std::time::Duration;
-use std::usize;
+use std::{cmp::Ordering, ffi::c_int, time::Duration, usize};
 
 /// Minimum security level for the keys/certificates used to establish a chain of
 /// trust (see https://www.openssl.org/docs/man1.1.1/man3/X509_VERIFY_PARAM_set_auth_level.html

rust/pv/src/verify/test.rs

@@ -8,6 +8,7 @@ use super::{helper, helper::*, *};
 use crate::{Error, HkdVerifyErrorType::*};
 use core::slice;
 use openssl::stack::Stack;
+use std::ffi::c_int;
 
 use crate::test_utils::*;
 
@@ -23,10 +24,10 @@ pub fn mock_endpt(res: &str) -> mockito::Mock {
 }
 
 #[track_caller]
-fn verify_sign_error(exp_raw: libc::c_int, obs: Error) {
+fn verify_sign_error(exp_raw: c_int, obs: Error) {
     verify_sign_error_slice(&[exp_raw], obs)
 }
-fn verify_sign_error_slice(exp_raw: &[libc::c_int], obs: Error) {
+fn verify_sign_error_slice(exp_raw: &[c_int], obs: Error) {
     if exp_raw
         .iter()
         .filter(|e| match &obs {