LibCore: Add Core::System wrappers for fstat() and fcntl()

Userland/Libraries/LibCore/System.cpp

@@ -6,6 +6,8 @@
 
 #include <LibCore/System.h>
 #include <LibSystem/syscall.h>
+#include <fcntl.h>
+#include <stdarg.h>
 
 #define HANDLE_SYSCALL_RETURN_VALUE(syscall_name, rc, success_value) \
     if ((rc) < 0) {                                                  \
@@ -44,4 +46,24 @@ ErrorOr<void> sigaction(int signal, struct sigaction const* action, struct sigac
     return {};
 }
 
+ErrorOr<struct stat> fstat(int fd)
+{
+    struct stat st = {};
+    if (::fstat(fd, &st) < 0)
+        return Error::from_syscall("fstat"sv, -errno);
+    return st;
+}
+
+ErrorOr<int> fcntl(int fd, int command, ...)
+{
+    va_list ap;
+    va_start(ap, command);
+    u32 extra_arg = va_arg(ap, u32);
+    int rc = ::fcntl(fd, command, extra_arg);
+    va_end(ap);
+    if (rc < 0)
+        return Error::from_syscall("fcntl"sv, -errno);
+    return rc;
+}
+
 }

Userland/Libraries/LibCore/System.h

@@ -8,6 +8,7 @@
 
 #include <AK/Error.h>
 #include <signal.h>
+#include <sys/stat.h>
 
 namespace Core::System {
 
@@ -17,5 +18,7 @@ ErrorOr<void> unveil(StringView path, StringView permissions);
 #endif
 
 ErrorOr<void> sigaction(int signal, struct sigaction const* action, struct sigaction* old_action);
+ErrorOr<struct stat> fstat(int fd);
+ErrorOr<int> fcntl(int fd, int command, ...);
 
 }