[LIBC] Fix getrandom success return value

`getrandom` should return the number of bytes successfully set on success, not `0`. Reviewed By: sivachandra, michaelrj Differential Revision: https://reviews.llvm.org/D147981
llvm · Apr 13, 2023 · ee361a3 · ee361a3
1 parent 203aff2
commit ee361a3
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Showing 2 changed files with 10 additions and 1 deletion.
diff --git a/libc/src/sys/random/linux/getrandom.cpp b/libc/src/sys/random/linux/getrandom.cpp
@@ -23,7 +23,7 @@ LLVM_LIBC_FUNCTION(ssize_t, getrandom,
     libc_errno = -ret;
     return -1;
   }
-  return 0;
+  return ret;
 }
 
 } // namespace __llvm_libc
diff --git a/libc/test/src/sys/random/linux/getrandom_test.cpp b/libc/test/src/sys/random/linux/getrandom_test.cpp
@@ -29,6 +29,15 @@ TEST(LlvmLibcGetRandomTest, InvalidBuffer) {
   libc_errno = 0;
 }
 
+TEST(LlvmLibcGetRandomTest, ReturnsSize) {
+  static constexpr size_t SIZE = 8192;
+  uint8_t buf[SIZE];
+  for (size_t i = 0; i < SIZE; ++i) {
+    // Without GRND_RANDOM set this should never fail.
+    ASSERT_EQ(__llvm_libc::getrandom(buf, i, 0), static_cast<ssize_t>(i));
+  }
+}
+
 TEST(LlvmLibcGetRandomTest, PiEstimation) {
   static constexpr size_t LIMIT = 10000000;
   static constexpr double PI = 3.14159265358979;