Improve error handling on nix systems

CHANGELOG.md

@@ -5,6 +5,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/), and this
 project adheres to [Semantic Versioning](https://semver.org/).
 
+## [0.2.3] - TBD
+### Changed
+- Improve error handling on nix systems (#108)
+
 ## [0.2.2] - 2020-08-27
 ### Added
 - Support for watchOS and tvOS (#98)

build.gradle.kts

@@ -1,7 +1,7 @@
 import org.jetbrains.kotlin.konan.target.HostManager
 
 plugins {
-    kotlin("multiplatform") version "1.4.0"
+    kotlin("multiplatform") version "1.4.10"
     id("org.jetbrains.dokka") version "0.9.18"
     id("maven-publish")
     id("signing")

src/nativeMain/kotlin/urandom.kt

@@ -0,0 +1,24 @@
+package com.benasher44.uuid
+
+import kotlinx.cinterop.ByteVar
+import kotlinx.cinterop.CPointer
+import kotlinx.cinterop.addressOf
+import kotlinx.cinterop.usePinned
+import platform.posix.O_RDONLY
+import platform.posix.close
+import platform.posix.errno
+import platform.posix.open
+
+internal fun bytesWithURandomFd(fdLambda: (Int, CPointer<ByteVar>) -> Unit): ByteArray {
+    return ByteArray(UUID_BYTES).also { bytes ->
+        val fd = open("/dev/urandom", O_RDONLY)
+        check(fd != -1) { "Failed to access /dev/urandom: $errno" }
+        try {
+            bytes.usePinned {
+                fdLambda(fd, it.addressOf(0))
+            }
+        } finally {
+            close(fd)
+        }
+    }
+}

src/nix32Main/kotlin/platform.kt

@@ -1,18 +1,9 @@
 package com.benasher44.uuid
 
-import kotlinx.cinterop.addressOf
-import kotlinx.cinterop.usePinned
-import platform.posix.O_RDONLY
-import platform.posix.close
-import platform.posix.open
 import platform.posix.read
 
 internal actual fun getRandomUuidBytes(): ByteArray {
-    val bytes = ByteArray(UUID_BYTES)
-    val fd = open("/dev/urandom", O_RDONLY)
-    bytes.usePinned {
-        read(fd, it.addressOf(0), UUID_BYTES.toUInt())
+    return bytesWithURandomFd { fd, bytePtr ->
+        read(fd, bytePtr, UUID_BYTES.toUInt())
     }
-    close(fd)
-    return bytes
 }

src/nix64Main/kotlin/platform.kt

@@ -1,19 +1,10 @@
 package com.benasher44.uuid
 
-import kotlinx.cinterop.addressOf
 import kotlinx.cinterop.convert
-import kotlinx.cinterop.usePinned
-import platform.posix.O_RDONLY
-import platform.posix.close
-import platform.posix.open
 import platform.posix.read
 
 internal actual fun getRandomUuidBytes(): ByteArray {
-    val bytes = ByteArray(UUID_BYTES)
-    val fd = open("/dev/urandom", O_RDONLY)
-    bytes.usePinned {
-        read(fd, it.addressOf(0), UUID_BYTES.convert())
+    return bytesWithURandomFd { fd, bytePtr ->
+        read(fd, bytePtr, UUID_BYTES.convert())
     }
-    close(fd)
-    return bytes
 }