[libc-commits] [libc] [libc] Add support for SYS_fchmodat2 in fchmodat (PR #223997)

[Pavel Labath via libc-commits]

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@@ -24,8 +25,24 @@
 namespace LIBC_NAMESPACE_DECL {
 namespace linux_syscalls {
 
-LIBC_INLINE ErrorOr<int> fchmodat(int fd, const char *path, mode_t mode) {
+LIBC_INLINE ErrorOr<int> fchmodat(int fd, const char *path, mode_t mode,
+                                  int flags) {
+#ifdef SYS_fchmodat2
+  int ret = syscall_impl<int>(SYS_fchmodat2, fd, path, mode, flags);
+#if defined(SYS_fchmodat)
+  if (ret == -ENOSYS) {
+    if (flags != 0)
+      return Error(ENOTSUP);
+    ret = syscall_impl<int>(SYS_fchmodat, fd, path, mode);
+  }
+#endif
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labath wrote:

I don't think we have fallbacks like this elsewhere (i.e. we generally assume that a SYS_whatever constant being defined means that the syscall is available). If you've seen this elsewhere, let me know. Otherwise, I'd just delete this.

https://github.com/llvm/llvm-project/pull/223997