Enable optional logging of failures

src/cloudabi.rs

@@ -19,6 +19,7 @@ pub fn getrandom_inner(dest: &mut [u8]) -> Result<(), Error> {
         Ok(())
     } else {
         let code = NonZeroU32::new(errno as u32).unwrap();
+        error!("cloudabi::random_get syscall failed with code {}", code);
         Err(Error::from(code))
     }
 }

src/dummy.rs

@@ -12,6 +12,7 @@ use std::num::NonZeroU32;
 use {Error, ERROR_UNAVAILABLE};
 
 pub fn getrandom_inner(_: &mut [u8]) -> Result<(), Error> {
+    error!("no support for this platform");
     Err(ERROR_UNAVAILABLE)
 }
 

src/freebsd.rs

@@ -26,6 +26,7 @@ pub fn getrandom_inner(dest: &mut [u8]) -> Result<(), Error> {
             )
         };
         if ret == -1 || len != chunk.len() {
+            error!("freebsd: kern.arandom syscall failed");
             return Err(io::Error::last_os_error().into());
         }
     }

src/lib.rs

@@ -113,7 +113,7 @@ extern crate wasm_bindgen;
 
 #[cfg(feature = "log")] #[macro_use] extern crate log;
 #[allow(unused)]
-#[cfg(not(feature = "log"))] macro_rules! warn { ($($x:tt)*) => () }
+#[cfg(not(feature = "log"))] macro_rules! error { ($($x:tt)*) => () }
 
 #[cfg(any(
     target_os = "android",

src/linux_android.rs

@@ -34,6 +34,7 @@ fn syscall_getrandom(dest: &mut [u8]) -> Result<(), io::Error> {
         libc::syscall(libc::SYS_getrandom, dest.as_mut_ptr(), dest.len(), 0)
     };
     if ret < 0 || (ret as usize) != dest.len() {
+        error!("Linux getrandom syscall failed with return value {}", ret);
         return Err(io::Error::last_os_error());
     }
     Ok(())

src/macos.rs

@@ -36,6 +36,7 @@ pub fn getrandom_inner(dest: &mut [u8]) -> Result<(), Error> {
         )
     };
     if ret == -1 {
+        error!("SecRandomCopyBytes call failed");
         Err(io::Error::last_os_error().into())
     } else {
         Ok(())

src/openbsd_bitrig.rs

@@ -22,6 +22,7 @@ pub fn getrandom_inner(dest: &mut [u8]) -> Result<(), Error> {
             )
         };
         if ret == -1 {
+            error!("libc::getentropy call failed");
             return Err(io::Error::last_os_error().into());
         }
     }

src/solarish.rs

@@ -45,6 +45,7 @@ fn libc_getrandom(rand: GetRandomFn, dest: &mut [u8]) -> Result<(), Error> {
     let ret = unsafe { rand(dest.as_mut_ptr(), dest.len(), 0) as libc::ssize_t };
 
     if ret == -1 || ret != dest.len() as libc::ssize_t {
+        error!("getrandom syscall failed with ret={}", ret);
         Err(io::Error::last_os_error().into())
     } else {
         Ok(())

src/wasm32_stdweb.rs

@@ -66,7 +66,7 @@ fn getrandom_init() -> Result<RngSource, Error> {
         else { unreachable!() }
     } else {
         let err: WebError = js!{ return @{ result }.error }.try_into().unwrap();
-        warn!("getrandom unavailable: {}", err);
+        error!("getrandom unavailable: {}", err);
         Err(ERROR_UNAVAILABLE)
     }
 }
@@ -102,7 +102,7 @@ fn getrandom_fill(source: &mut RngSource, dest: &mut [u8]) -> Result<(), Error>
 
         if js!{ return @{ result.as_ref() }.success } != true {
             let err: WebError = js!{ return @{ result }.error }.try_into().unwrap();
-            warn!("getrandom failed: {}", err);
+            error!("getrandom failed: {}", err);
             return Err(ERROR_UNKNOWN)
         }
     }

src/windows.rs

@@ -20,7 +20,10 @@ pub fn getrandom_inner(dest: &mut [u8]) -> Result<(), Error> {
     let ret = unsafe {
         RtlGenRandom(dest.as_mut_ptr() as PVOID, dest.len() as ULONG)
     };
-    if ret == 0 { return Err(io::Error::last_os_error().into()); }
+    if ret == 0 {
+        error!("RtlGenRandom call failed");
+        return Err(io::Error::last_os_error().into());
+    }
     Ok(())
 }