LibSystem: Add wrapper for fstat()

Userland/Libraries/LibSystem/Wrappers.cpp

@@ -7,11 +7,11 @@
 #include <LibSystem/Wrappers.h>
 #include <LibSystem/syscall.h>
 
-#define HANDLE_SYSCALL_RETURN_VALUE(syscall_name, rc) \
-    if ((rc) < 0) {                                   \
-        return Error::from_syscall(syscall_name, rc); \
-    }                                                 \
-    return {};
+#define HANDLE_SYSCALL_RETURN_VALUE(syscall_name, rc, success_value) \
+    if ((rc) < 0) {                                                  \
+        return Error::from_syscall(syscall_name, rc);                \
+    }                                                                \
+    return success_value;
 
 namespace System {
 
@@ -22,7 +22,7 @@ ErrorOr<void> pledge(StringView promises, StringView execpromises)
         { execpromises.characters_without_null_termination(), execpromises.length() },
     };
     int rc = syscall(SC_pledge, &params);
-    HANDLE_SYSCALL_RETURN_VALUE("pledge"sv, rc);
+    HANDLE_SYSCALL_RETURN_VALUE("pledge"sv, rc, {});
 }
 
 ErrorOr<void> unveil(StringView path, StringView permissions)
@@ -32,13 +32,20 @@ ErrorOr<void> unveil(StringView path, StringView permissions)
         { permissions.characters_without_null_termination(), permissions.length() },
     };
     int rc = syscall(SC_unveil, &params);
-    HANDLE_SYSCALL_RETURN_VALUE("unveil"sv, rc);
+    HANDLE_SYSCALL_RETURN_VALUE("unveil"sv, rc, {});
 }
 
 ErrorOr<void> sigaction(int signal, struct sigaction const* action, struct sigaction* old_action)
 {
     int rc = syscall(SC_sigaction, signal, action, old_action);
-    HANDLE_SYSCALL_RETURN_VALUE("sigaction"sv, rc);
+    HANDLE_SYSCALL_RETURN_VALUE("sigaction"sv, rc, {});
+}
+
+ErrorOr<struct stat> fstat(int fd)
+{
+    struct stat st;
+    int rc = syscall(SC_fstat, fd, &st);
+    HANDLE_SYSCALL_RETURN_VALUE("fstat"sv, rc, st);
 }
 
 }

Userland/Libraries/LibSystem/Wrappers.h

@@ -8,11 +8,13 @@
 
 #include <AK/Error.h>
 #include <signal.h>
+#include <sys/stat.h>
 
 namespace System {
 
 ErrorOr<void> pledge(StringView promises, StringView execpromises);
 ErrorOr<void> unveil(StringView path, StringView permissions);
 ErrorOr<void> sigaction(int signal, struct sigaction const* action, struct sigaction* old_action);
+ErrorOr<struct stat> fstat(int fd);
 
 }