[libc-commits] [libc] [libc] add statvfs/fstatvfs (PR #86169)

[Nick Desaulniers via libc-commits]

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@@ -14,11 +14,10 @@ namespace LIBC_NAMESPACE {
 
 LLVM_LIBC_FUNCTION(int, fstatvfs, (int fd, struct statvfs *buf)) {
   using namespace statfs_utils;
-  if (cpp::optional<LinuxStatFs> result = linux_fstatfs(fd)) {
-    *buf = statfs_to_statvfs(*result);
-    return 0;
-  }
-  return -1;
+  cpp::optional<LinuxStatFs> result = linux_fstatfs(fd);
+  if (result)
+    statfs_to_statvfs(*result, *buf);
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nickdesaulniers wrote:

Seeing pointers from userspace get immediately converted to references is a great way to wind up with UB.

These interfaces in particular are ones I hope to address with: https://github.com/llvm/llvm-project/issues/86527

Do you mind adding `LIBC_ASSERT`s here and for `statvfs` below?

https://github.com/llvm/llvm-project/pull/86169