Improve usage of getrandom for generating bytes

Single_Header/dn_single_header.cpp

@@ -1,4 +1,4 @@
-// Generated by the DN single header generator 2025-07-30 18:54:02
+// Generated by the DN single header generator 2025-08-02 22:07:04
 
 #define DN_BASE_INC_CPP
 
@@ -6513,32 +6513,24 @@ DN_API DN_OSDateTime DN_OS_DateUnixTimeSToDate(uint64_t time)
   return result;
 }
 
-DN_API bool DN_OS_SecureRNGBytes(void *buffer, DN_U32 size)
+DN_API void DN_OS_GenBytesSecure(void *buffer, DN_U32 size)
 {
 #if defined(DN_PLATFORM_EMSCRIPTEN)
+  DN_InvalidCodePath;
   (void)buffer;
   (void)size;
-  return false;
 #else
-  if (!buffer || size < 0)
+  DN_Assert(buffer && size);
-    return false;
+  DN_USize bytes_written = 0;
-
+  while (bytes_written < size) {
-  if (size == 0)
+    DN_USize bytes_remaining = size - bytes_written;
-    return true;
+    DN_USize need_amount     = DN_Min(bytes_remaining, 32);
-
+    DN_USize bytes_read      = 0;
-  DN_AssertF(size <= 32,
+    do {
-             "We can increase this by chunking the buffer and filling 32 bytes at a time. *Nix "
+      bytes_read = getrandom((DN_U8 *)buffer + bytes_written, need_amount, 0);
-             "guarantees 32 "
+    } while (bytes_read != need_amount || errno == EAGAIN || errno == EINTR);
-             "bytes can always be fulfilled by this system at a time");
+    bytes_written += bytes_read;
-  // TODO(doyle):
+  }
-  // https://github.com/jedisct1/libsodium/blob/master/src/libsodium/randombytes/sysrandom/randombytes_sysrandom.c
-  // TODO(doyle): https://man7.org/linux/man-pages/man2/getrandom.2.html
-  DN_U32 read_bytes = 0;
-  do {
-    read_bytes =
-        getrandom(buffer, size, 0); // NOTE: EINTR can not be triggered if size <= 32 bytes
-  } while (read_bytes != size || errno == EAGAIN);
-  return true;
 #endif
 }
 
@@ -8105,24 +8097,16 @@ DN_API DN_OSDateTime DN_OS_DateUnixTimeSToDate(DN_U64 time)
   return result;
 }
 
-DN_API bool DN_OS_SecureRNGBytes(void *buffer, DN_U32 size)
+DN_API void DN_OS_GenBytesSecure(void *buffer, DN_U32 size)
 {
   DN_Assert(g_dn_os_core_);
   DN_W32Core *w32 = DN_CAST(DN_W32Core *) g_dn_os_core_->platform_context;
-
+  DN_Assert(w32->bcrypt_init_success);
-  if (!buffer || size < 0 || !w32->bcrypt_init_success)
-    return false;
-
-  if (size == 0)
-    return true;
 
   long gen_status = BCryptGenRandom(w32->bcrypt_rng_handle, DN_CAST(unsigned char *) buffer, size, 0 /*flags*/);
-  if (gen_status != 0) {
+  // NOTE: This can only fail if the handle is invalid or one or more parameters are invalid. We
-    DN_LOG_ErrorF("Failed to generate random bytes: %d", gen_status);
+  // validate our parameters so this shouldn't be the case.
-    return false;
+  DN_Assert(gen_status == 0);
-  }
-
-  return true;
 }
 
 DN_API DN_OSDiskSpace DN_OS_DiskSpace(DN_Str8 path)

Single_Header/dn_single_header.h

@@ -1,4 +1,4 @@
-// Generated by the DN single header generator 2025-07-30 18:54:02
+// Generated by the DN single header generator 2025-08-02 22:07:04
 
 #if !defined(DN_BASE_INC_H)
 #define DN_BASE_INC_H
@@ -6097,7 +6097,7 @@ DN_API DN_U64                    DN_OS_DateToUnixTimeS     (DN_OSDateTime date);
 DN_API bool                      DN_OS_DateIsValid         (DN_OSDateTime date);
 
 // NOTE: Other /////////////////////////////////////////////////////////////////////////////////////
-DN_API bool                      DN_OS_SecureRNGBytes      (void *buffer, DN_U32 size);
+DN_API void                      DN_OS_GenBytesSecure      (void *buffer, DN_U32 size);
 DN_API bool                      DN_OS_SetEnvVar           (DN_Str8 name, DN_Str8 value);
 DN_API DN_OSDiskSpace            DN_OS_DiskSpace           (DN_Str8 path);
 DN_API DN_Str8                   DN_OS_EXEPath             (DN_Arena *arena);

Source/Extra/dn_tests.cpp

@@ -1821,27 +1821,13 @@ static DN_UTCore DN_Tests_OS()
 #if defined(DN_OS_INC_CPP) || 1
   DN_UT_LogF(&result, "DN_OS\n");
   {
-    for (DN_UT_Test(&result, "Generate secure RNG bytes with nullptr")) {
-      DN_B32 os_result = DN_OS_SecureRNGBytes(nullptr, 1);
-      DN_UT_Assert(&result, os_result == false);
-    }
-
     for (DN_UT_Test(&result, "Generate secure RNG 32 bytes")) {
       char const ZERO[32]  = {};
       char       buf[32]   = {};
-      bool       os_result = DN_OS_SecureRNGBytes(buf, DN_ArrayCountU(buf));
+      DN_OS_GenBytesSecure(buf, DN_ArrayCountU(buf));
-      DN_UT_Assert(&result, os_result);
       DN_UT_Assert(&result, DN_Memcmp(buf, ZERO, DN_ArrayCountU(buf)) != 0);
     }
 
-    for (DN_UT_Test(&result, "Generate secure RNG 0 bytes")) {
-      char buf[32]     = {};
-      buf[0]           = 'Z';
-      DN_B32 os_result = DN_OS_SecureRNGBytes(buf, 0);
-      DN_UT_Assert(&result, os_result);
-      DN_UT_Assert(&result, buf[0] == 'Z');
-    }
-
     for (DN_UT_Test(&result, "Query executable directory")) {
       DN_OSTLSTMem tmem      = DN_OS_TLSTMem(nullptr);
       DN_Str8      os_result = DN_OS_EXEDir(tmem.arena);

Source/OS/dn_os.h

@@ -331,7 +331,7 @@ DN_API DN_U64                    DN_OS_DateToUnixTimeS     (DN_OSDateTime date);
 DN_API bool                      DN_OS_DateIsValid         (DN_OSDateTime date);
 
 // NOTE: Other /////////////////////////////////////////////////////////////////////////////////////
-DN_API bool                      DN_OS_SecureRNGBytes      (void *buffer, DN_U32 size);
+DN_API void                      DN_OS_GenBytesSecure      (void *buffer, DN_U32 size);
 DN_API bool                      DN_OS_SetEnvVar           (DN_Str8 name, DN_Str8 value);
 DN_API DN_OSDiskSpace            DN_OS_DiskSpace           (DN_Str8 path);
 DN_API DN_Str8                   DN_OS_EXEPath             (DN_Arena *arena);

Source/OS/dn_os_posix.cpp

@@ -162,32 +162,24 @@ DN_API DN_OSDateTime DN_OS_DateUnixTimeSToDate(uint64_t time)
   return result;
 }
 
-DN_API bool DN_OS_SecureRNGBytes(void *buffer, DN_U32 size)
+DN_API void DN_OS_GenBytesSecure(void *buffer, DN_U32 size)
 {
 #if defined(DN_PLATFORM_EMSCRIPTEN)
+  DN_InvalidCodePath;
   (void)buffer;
   (void)size;
-  return false;
 #else
-  if (!buffer || size < 0)
+  DN_Assert(buffer && size);
-    return false;
+  DN_USize bytes_written = 0;
-
+  while (bytes_written < size) {
-  if (size == 0)
+    DN_USize bytes_remaining = size - bytes_written;
-    return true;
+    DN_USize need_amount     = DN_Min(bytes_remaining, 32);
-
+    DN_USize bytes_read      = 0;
-  DN_AssertF(size <= 32,
+    do {
-             "We can increase this by chunking the buffer and filling 32 bytes at a time. *Nix "
+      bytes_read = getrandom((DN_U8 *)buffer + bytes_written, need_amount, 0);
-             "guarantees 32 "
+    } while (bytes_read != need_amount || errno == EAGAIN || errno == EINTR);
-             "bytes can always be fulfilled by this system at a time");
+    bytes_written += bytes_read;
-  // TODO(doyle):
+  }
-  // https://github.com/jedisct1/libsodium/blob/master/src/libsodium/randombytes/sysrandom/randombytes_sysrandom.c
-  // TODO(doyle): https://man7.org/linux/man-pages/man2/getrandom.2.html
-  DN_U32 read_bytes = 0;
-  do {
-    read_bytes =
-        getrandom(buffer, size, 0); // NOTE: EINTR can not be triggered if size <= 32 bytes
-  } while (read_bytes != size || errno == EAGAIN);
-  return true;
 #endif
 }
 

Source/OS/dn_os_w32.cpp

@@ -223,24 +223,16 @@ DN_API DN_OSDateTime DN_OS_DateUnixTimeSToDate(DN_U64 time)
   return result;
 }
 
-DN_API bool DN_OS_SecureRNGBytes(void *buffer, DN_U32 size)
+DN_API void DN_OS_GenBytesSecure(void *buffer, DN_U32 size)
 {
   DN_Assert(g_dn_os_core_);
   DN_W32Core *w32 = DN_CAST(DN_W32Core *) g_dn_os_core_->platform_context;
-
+  DN_Assert(w32->bcrypt_init_success);
-  if (!buffer || size < 0 || !w32->bcrypt_init_success)
-    return false;
-
-  if (size == 0)
-    return true;
 
   long gen_status = BCryptGenRandom(w32->bcrypt_rng_handle, DN_CAST(unsigned char *) buffer, size, 0 /*flags*/);
-  if (gen_status != 0) {
+  // NOTE: This can only fail if the handle is invalid or one or more parameters are invalid. We
-    DN_LOG_ErrorF("Failed to generate random bytes: %d", gen_status);
+  // validate our parameters so this shouldn't be the case.
-    return false;
+  DN_Assert(gen_status == 0);
-  }
-
-  return true;
 }
 
 DN_API DN_OSDiskSpace DN_OS_DiskSpace(DN_Str8 path)