Userland: Implement simple lspci command

Kernel/FileSystem/ProcFS.cpp

@@ -268,7 +268,7 @@ Optional<KBuffer> procfs$pci(InodeIdentifier)
         obj.set("class", PCI::get_class(address));
         obj.set("subsystem_id", PCI::get_subsystem_id(address));
         obj.set("subsystem_vendor_id", PCI::get_subsystem_vendor_id(address));
-        json.append(obj);
+        json.append(move(obj));
     });
     return json.serialized<KBufferBuilder>();
 }

Userland/lspci.cpp

@@ -0,0 +1,38 @@
+#include <AK/AKString.h>
+#include <AK/JsonArray.h>
+#include <AK/JsonObject.h>
+#include <LibCore/CFile.h>
+#include <stdio.h>
+
+int main(int argc, char** argv)
+{
+    UNUSED_PARAM(argc);
+    UNUSED_PARAM(argv);
+
+    CFile file("/proc/pci");
+    if (!file.open(CIODevice::ReadOnly)) {
+        fprintf(stderr, "Error: %s\n", file.error_string());
+        return 1;
+    }
+
+    auto file_contents = file.read_all();
+    auto json = JsonValue::from_string(file_contents).as_array();
+    json.for_each([](auto& value) {
+        auto dev = value.as_object();
+
+        auto bus = dev.get("bus").to_u32();
+        auto slot = dev.get("slot").to_u32();
+        auto function = dev.get("function").to_u32();
+        auto vendor_id = dev.get("vendor_id").to_u32();
+        auto device_id = dev.get("device_id").to_u32();
+        auto revision_id = dev.get("revision_id").to_u32();
+        auto class_id = dev.get("class").to_u32();
+
+        printf("%02x:%02x.%d %04x: %04x:%04x (rev %02x)\n",
+            bus, slot, function,
+            class_id, vendor_id, device_id, revision_id
+        );
+    });
+
+    return 0;
+}