LibC: Bug fix, make sure to invalidate cache if it skips using it

Since when the cache gets skipped the offset in the file increases
far outside of the reach of the current cache. Therefore the current
cache should be discarded.

1 files changed, 6 insertions, 1 deletions

diff --git a/userland/libc/stdio/stdin.c b/userland/libc/stdio/stdin.c
index 98189e2..2ced1a0 100644
--- a/userland/libc/stdio/stdin.c
+++ b/userland/libc/stdio/stdin.c
@@ -31,7 +31,12 @@ size_t read_fd(FILE *f, unsigned char *s, size_t l) {
   // equal to the cache block size. This avoids doing a bunch of extra
   // syscalls
   if (l >= 4096) {
-    return non_cache_read_fd(f, s, l);
+    // Invalidate the cache
+f->read_buffer_stored = 0;
+
+    size_t rc = non_cache_read_fd(f, s, l);
+    f->offset_in_file += rc;
+    return rc;
   }
 
   if (!f->read_buffer) {