Merge pull request #15317 from devnexen/darwin_rand_nativegen

std: add CCRandomGenerateBytes macOs native api.

lib/std/c/darwin.zig

@@ -897,7 +897,35 @@ pub extern "c" fn pthread_attr_get_qos_class_np(attr: *pthread_attr_t, qos_class
 pub extern "c" fn pthread_set_qos_class_self_np(qos_class: qos_class_t, relative_priority: c_int) c_int;
 pub extern "c" fn pthread_get_qos_class_np(pthread: std.c.pthread_t, qos_class: *qos_class_t, relative_priority: *c_int) c_int;
 
+pub const CCryptorStatus = enum(i32) {
+    /// Operation completed
+    kCCSuccess = 0,
+    /// Illegal parameter
+    kCCParamError = -4300,
+    /// Provided buffer too small
+    kCCBufferTooSmall = -4301,
+    /// Failed memory allocation
+    kCCMemoryFailure = -4302,
+    /// Size alignment issue
+    kCCAlignmentError = -4303,
+    /// Decoding issue
+    kCCDecodeError = -4304,
+    /// Call not implemented
+    kCCUnimplemented = -4305,
+    kCCOverflow = -4306,
+    kCCRNGFailure = -4307,
+    /// Unspecified error
+    kCCUnspecifiedError = -4308,
+    kCCCallSequenceError = -4309,
+    kCCKeySizeError = -4310,
+    /// Invalid key
+    kCCInvalidKey = -4311,
+};
+
+pub const CCRNGStatus = CCryptorStatus;
+
 pub extern "c" fn arc4random_buf(buf: [*]u8, len: usize) void;
+pub extern "c" fn CCRandomGenerateBytes(bytes: ?*anyopaque, count: usize) CCRNGStatus;
 
 // Grand Central Dispatch is exposed by libSystem.
 pub extern "c" fn dispatch_release(object: *anyopaque) void;

lib/std/os.zig

@@ -512,7 +512,18 @@ pub fn getrandom(buffer: []u8) GetRandomError!void {
         return;
     }
     switch (builtin.os.tag) {
-        .netbsd, .openbsd, .macos, .ios, .tvos, .watchos => {
+        .macos, .ios => {
+            const rc = darwin.CCRandomGenerateBytes(buffer.ptr, buffer.len);
+            if (rc != darwin.CCRNGStatus.kCCSuccess) {
+                if (rc == darwin.CCRNGStatus.kCCParamError or rc == darwin.CCRNGStatus.kCCBufferTooSmall) {
+                    return error.InvalidHandle;
+                } else {
+                    return error.SystemResources;
+                }
+            }
+            return;
+        },
+        .netbsd, .openbsd, .tvos, .watchos => {
             system.arc4random_buf(buffer.ptr, buffer.len);
             return;
         },
@@ -991,7 +1002,7 @@ pub fn preadv(fd: fd_t, iov: []const iovec, offset: u64) PReadError!usize {
     if (have_pread_but_not_preadv) {
         // We could loop here; but proper usage of `preadv` must handle partial reads anyway.
         // So we simply read into the first vector only.
-        if (iov.len == 0) return @as(usize, 0);
+        if (iov.len == 0) return @intCast(usize, 0);
         const first = iov[0];
         return pread(fd, first.iov_base[0..first.iov_len], offset);
     }