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Please help!
I'm trying to open a USB connection to an existing device with a listed active interface.
For that I need to open a file using a device id (path).
But CreateFile() fails with ERROR_PATH_NOT_FOUND (error code 3).
I got the following device ids from the Windows 10 Device Manager on my computer ...
"USB\VID_046D&PID_C534&MI_00\6&168DEF1E&0&0000"
"USB\VID_046D&PID_C534&MI_01\6&168DEF1E&0&0001"
"USB\VID_04F2&PID_B5EE&MI_00\6&237200EE&0&0000"
... and ran the following trivial program using one of them as input to CreateFile():
#include "..\..\test_wconsole\test_wconsole\_wconsole_.h"
#include "conio.h"
int APIENTRY wWinMain(_In_ HINSTANCE hi, _In_opt_ HINSTANCE hpi, _In_ LPWSTR c, _In_ int cs)
{
const WCHAR* path = L"USB\\VID_046D&PID_C534&MI_01\\6&168DEF1E&0&0001";
wcprintf("\nopening file \"%ws\" ... ", path);
HANDLE h_usbdevice = CreateFile
(
path,
GENERIC_READ | GENERIC_WRITE,
FILE_SHARE_READ | FILE_SHARE_WRITE,
NULL,
OPEN_EXISTING, FILE_FLAG_OVERLAPPED,
NULL
);
if (h_usbdevice != INVALID_HANDLE_VALUE) wcprintf("done\n"); else wcprintf("error %lu\n", GetLastError());
{ wcprintf("\n\tPress any key to proceed ... "); wcprintf("%i\n\n", _getch()); }
return NULL;
}
Here is a copy of the program’s console output:
opening file "USB\VID_046D&PID_C534&MI_01\6&168DEF1E&0&0001" ... error 3
Press any key to proceed ...
Running the program with Administrator privileges yields the same result. What am I doing wrong?
I wrote a sketch for ESP8266. This sketch reads some sensor data and published it via MQTT. In addition I want to let a Web server provide the same data as HTML, or JSON web service.
The MQTT publish is triggered via a TaskScheduler timer.
Both functions, MQTT and Web server, work for itself, but sadly not together. Here's a simplified sketch:
#include <ESP8266WiFi.h>
#include <ESP8266mDNS.h>
#include <ESP8266WebServerSecure.h>
#include <PubSubClient.h>
#include <TaskScheduler.h>
#include <My_WLAN.h> // provices connection to local WLAN and network settings
const char DNS_NAME[] = "myserver.local";
const int HTTPS_PORT = 443; // HTTPS
const char MQTT_SVR[] = "myserver.local";
const unsigned int MQTT_PORT = 8883; // MQTTS
WiFiClientSecure wifiClient;
PubSubClient mqttClient(wifiClient); // MQTT client instance
ESP8266WebServerSecure server(HTTPS_PORT); // web server instance
void t1Callback(void); // callback method prototypes
Task t1(60000, TASK_FOREVER, &t1Callback); // main loop task
Scheduler timer; // task scheduler
static const uint8_t SVR_FINGERPRINT[20] PROGMEM = { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x20 };
static const char deviceCert[] PROGMEM = R"EOF(
-----BEGIN CERTIFICATE-----
[... certificate ...]
-----END CERTIFICATE-----
)EOF";
static const char deviceKey[] PROGMEM = R"EOF(
-----BEGIN RSA PRIVATE KEY-----
[... key ...]
-----END RSA PRIVATE KEY-----
)EOF";
/* *****************************
MQTT_connect
* *****************************/
void MQTT_connect()
{
int attempt = 0;
/* loop until reconnected */
while (!mqttClient.connected() && attempt < 10) {
attempt++;
Serial.print("Attempting MQTT connection ("); Serial.print(attempt); Serial.print(")...");
mqttClient.setServer(MQTT_SVR, MQTT_PORT);
if (mqttClient.connect(DNS_NAME)) {
Serial.println("success");
} else {
Serial.print("failed, status code = "); Serial.print(mqttClient.state());
Serial.println(". - Try again in 5 seconds...");
delay(5000);
}
}
}
/* *****************************
Web Server handleRoot
* *****************************/
void handleRoot() {
digitalWrite(LED_BUILTIN, LOW); // on
Serial.println("WebServer ROOT");
server.send(200, "text/html", "WebServer ROOT");
digitalWrite(LED_BUILTIN, HIGH); // off
}
/* *****************************
Web Server handleNotFound
* *****************************/
void handleNotFound() {
digitalWrite(LED_BUILTIN, LOW); // on
String message = "File not found\n\n";
message += "URI: ";
message += server.uri();
message += "\nMethod: ";
message += (server.method() == HTTP_GET) ? "GET" : "POST";
message += "\nArguments: ";
message += server.args();
message += "\n";
for (uint8_t i = 0; i < server.args(); i++) {
message += " " + server.argName(i) + ": " + server.arg(i) + "\n";
}
server.send(404, "text/plain", message);
digitalWrite(LED_BUILTIN, HIGH); // off
}
/* *************************
MQTT_publish_something
* *************************/
void MQTT_publish_something() {
digitalWrite(LED_BUILTIN, LOW); // on
char payload[30] = "some_payload_data";
if (!mqttClient.publish("MQTT/Test", payload, true)) { // retain message
Serial.println("MQTT message lost!");
}
digitalWrite(LED_BUILTIN, HIGH); // off
}
/* *************************
t1: main timer (callback)
* *************************/
void t1Callback() {
my.WiFi_connect(); // check and re-connect to WLAN (in My_WLAN.h)
if (WiFi.status() == WL_CONNECTED) {
MQTT_connect();
MQTT_publish_something();
}
}
/* *************************
setup
* *************************/
void setup() {
pinMode(LED_BUILTIN, OUTPUT); // internal LED
digitalWrite(LED_BUILTIN, HIGH); // off
/* -----------------------
open Serial |
----------------------- */
Serial.begin(74880);
while (!Serial); // wait for Serial being ready
/* -----------------------
connect to WLAN |
----------------------- */
my.WiFi_connect(); // this is connecting to WLAN & error handling (in My_WLAN.h)
wifiClient.setFingerprint(SVR_FINGERPRINT);
/* -----------------------
set mDNS |
----------------------- */
if (MDNS.begin(DNS_NAME)) {
Serial.printf("mDNS responder started for %s\n", DNS_NAME);
MDNS.addService("https", "tcp", HTTPS_PORT); // add service to MDNS-SD
MDNS.addService("mqtt", "tcp", MQTT_PORT);
} else
Serial.println("Error setting up mDNS responder!");
/* -----------------------
start HTTPS server |
----------------------- */
server.getServer().setRSACert(new X509List(deviceCert), new PrivateKey(deviceKey));
server.on("/", handleRoot); // standard HTML root
server.onNotFound(handleNotFound);
server.begin();
Serial.println("HTTPS server started.");
Serial.println();
/* -----------------------
start timer |
----------------------- */
timer.init();
timer.addTask(t1);
// line 177:
timer.enableAll();
}
void loop() {
MDNS.update();
// line 184:
server.handleClient();
mqttClient.loop();
timer.execute();
}
Running MQTT only works fine and publishes data (I use the mosquitto broker).
Running the Web server (https://...) works fine as well, if commenting out line 177 (so MQTT does not get triggered).
With both functions active, as soon as the first MQTT message had been sent, the web server does not answer any more. I get PR_END_OF_FILE_ERROR in FF and ERR_CONNECTION_CLOSED in Chrome.
I guess, that these libraries somehow mess with each other, or that something confuses with the certificates. However, the fingerprint belongs to the server running mosquitto, while the X509 certificate belongs to the web server running on the ESP8266. These are two different machines and have nothing to do with each other.
Any idea welcome.
I suspect both libraries use port 443, and you can only have one listener on a given port. I've tried creating a BearSSL::ESP8266WebServerSecure object with alternate ports, such as 80 and 8443 but can't get them to work. Worse, there doesn't seem to be a way to stop a listener once a BearSSL::ESP8266WebServerSecure object has started, so it can't be released for later reuse.
I ended up using HTTP to get WiFi credentials, then HTTPS from there on out. Not a very satisfactory solution but it works.
Update: I was able to run a provisioning server on port 443, stop it by calling
BearSSL::ESP8266WebServerSecure provisioningServer(443);
BearSSL::ESP8266WebServerSecure server(443);
provisioningServer.close();
provisioningServer.~ESP8266WebServerSecure(); // note: cannot use TLS on both servers without this line
After calling the provisioning server's destructor I was able to start my server on port 443.
I have a program compiled and running on Ubuntu server 16.04, in C using Mongo C driver. This works without a problem. If I move this executable to a new installation, I get an error when executing;
testuser#usrv1604:~/bin$ ./error-example
./error-example: symbol lookup error: ./error-example: undefined symbol: mongoc_uri_new_with_error
Always the same error message.
Please see simplified code example below:
#include <stdio.h>
#include <strings.h>
#include <mongoc.h>
int
main (int argc, char *argv[])
{
const char *uri_string = "mongodb://localhost:27017";
mongoc_uri_t *uri;
mongoc_client_t *client;
mongoc_database_t *database;
mongoc_collection_t *collection;
bson_t *command, reply, *insert;
bson_t *b;
bson_error_t error;
mongoc_init ();
uri = mongoc_uri_new_with_error (uri_string, &error);
if (!uri) {
fprintf (stderr,
"failed to parse URI: %s\n"
"error message: %s\n",
uri_string,
error.message);
return EXIT_FAILURE;
}
client = mongoc_client_new_from_uri (uri);
if (!client) {
fprintf(stderr, "mongoc_client_new_from_uri() failed \n");
return EXIT_FAILURE;
}
mongoc_client_set_appname (client, "log-lme");
database = mongoc_client_get_database (client, "sds");
collection = mongoc_client_get_collection (client, "sds", "test");
//
// update db
//
// clean up
mongoc_collection_destroy (collection);
mongoc_database_destroy (database);
mongoc_uri_destroy (uri);
mongoc_client_destroy (client);
mongoc_cleanup ();
return EXIT_SUCCESS;
}
Please check the mongoc driver version installed on the target system. You must have version 1.8 or later to use this API: http://mongoc.org/libmongoc/1.8.0/mongoc_uri_new_with_error.html
I'm just start few test in vala.
Vala is new for me . Sure I started to read a lot of tuto, but I don't understand my mistake.
how to use and compile the follow code?
using Gtk;
#include <stdio.h>
// compile with valac --pkg gtk+-3.0 hello_world_gtk_01.vala
public const int EXIT_SUCCESS=0;
int main (string[] args)
{
Gtk.init (ref args);
var window = new Window ();
window.title = "Hello, World!";
window.border_width = 10;
window.window_position = WindowPosition.CENTER;
window.set_default_size (350, 70);
window.destroy.connect (Gtk.main_quit);
stdout.printf ("Version de gtk: %d.%d.%d\n", MAJOR_VERSION, MINOR_VERSION, MICRO_VERSION);
stdout.printf ("Version de gtk: %u.%u.%u\n", get_major_version() , get_minor_version(), get_micro_version());
string name, str;
name = "Version de gtk: ";
sprintf(str, "%d", get_major_version());
name = name+ str;
sprintf(str, "%d", get_minor_version());
name = name+ str;
sprintf(str, "%d", get_micro_version());
name = name+ str+ "\n";
var label = new Label (name);
window.add (label);
window.show_all ();
Gtk.main ();
return EXIT_SUCCESS;
}
What is bad ?
Gcc said
hello_world_gtk_01.vala:2.2-2.9: error: syntax error, invalid preprocessing directive
#include <stdio.h>
^^^^^^^^
hello_world_gtk_01.vala:2.10-2.10: error: syntax error, expected identifier
#include <stdio.h>
^
Compilation failed: 2 error(s), 0 warning(s)
could you help me to understand how to manage stdio?
Vala generates C code, but you can't pass C straight from the Vala file to the generated C. The Vala [CCode] attribute gives fine control over the generated C, but you won't need that in most cases. For an example of standard C names and their GLib equivalents take a look at the glib-2.0.vapi file in the Vala repository. Other standard C and POSIX extensions are in posix.vapi. There is also an in depth tutorial on writing a binding from Vala to a C library. Writing a binding, however, is a more advanced topic and what you are trying to achieve in your example doesn't need a new binding.
Your example uses string interpolation. In Vala a data type can have a method, so one way to write what you want would be:
name = "Version de gtk: %u.%u.%u\n".printf( get_major_version (), get_minor_version (), get_micro_version ());
Vala also has a string template syntax, #"", and and then an expression, $(), inside the string is evaluated. For example:
name = #"Version de gtk: $(get_major_version ()).$(get_minor_version ()).$(get_micro_version ())\n";
This works because uint, the return value of the function calls, has a to_string () method that is implicitly called by the string template.
Here's your example modified to use the string template method:
using Gtk;
// compile with valac --pkg gtk+-3.0 hello_world_gtk_01.vala
public const int EXIT_SUCCESS=0;
int main (string[] args)
{
Gtk.init (ref args);
var window = new Window ();
window.title = "Hello, World!";
window.border_width = 10;
window.window_position = WindowPosition.CENTER;
window.set_default_size (350, 70);
window.destroy.connect (Gtk.main_quit);
stdout.printf ("Version de gtk: %d.%d.%d\n", MAJOR_VERSION, MINOR_VERSION, MICRO_VERSION);
stdout.printf ("Version de gtk: %u.%u.%u\n", get_major_version() , get_minor_version(), get_micro_version());
var name = #"Version de gtk: $(get_major_version ()).$(get_minor_version ()).$(get_micro_version ())\n";
var label = new Label (name);
window.add (label);
window.show_all ();
Gtk.main ();
return EXIT_SUCCESS;
}
I'm writing an EFI executable on a SoC device (Up Board) to help us automate BIOS updates and PXE boots for installating our software on numerous devices.
The problem I have is that seemingly most of the protocols in the specification are "unsupported" on this platform, even basic file system tasks. The only one I've successfully used is the LOADED_IMAGE_PROTOCOL. I'm using gnu-efi to compile the code, basing my code to this example https://mjg59.dreamwidth.org/18773.html. Is there something I'm doing wrong, or is this simply the firmware absolutely not implementing any of the protocols?
The American Megatrends utility "AfuEfix64.efi" is capable of retrieving BIOS information, and the SoC BIOS updates are done using an Intel's EFI executable. Both are closed source, unfortunately. My initial idea would have been to write a script that parses the output from these executables, but I don't think the EFI shell has much features for this type of tasks, so I moved on to writing an EFI executable to perform this.
Minimal code showing this:
#include <efi.h>
#include <efilib.h>
#include <x86_64/efibind.h>
// gnu-efi does not currently define firmware management
// https://raw.githubusercontent.com/tianocore/edk2/master/MdePkg/Include/Protocol/FirmwareManagement.h
#include "efifirmware.h"
// gnu-efi does not currently define this
#define EFI_LOAD_FILE2_PROTOCOL_GUID \
{ 0x4006c0c1, 0xfcb3, 0x403e, \
{ 0x99, 0x6d, 0x4a, 0x6c, 0x87, 0x24, 0xe0, 0x6d }}
typedef EFI_LOAD_FILE_PROTOCOL EFI_LOAD_FILE2_PROTOCOL;
void tryProtocol(EFI_GUID proto_guid, void** out, const CHAR16* name,
EFI_HANDLE imageHandle, EFI_SYSTEM_TABLE* systemTable) {
EFI_STATUS status;
status = uefi_call_wrapper(systemTable->BootServices->HandleProtocol, 3,
imageHandle, &proto_guid, out);
if (EFI_ERROR(status)) {
Print(L"HandleProtocol error for %s: %r\n", name, status);
} else {
Print(L"Protocol %s is supported\n", name);
}
}
void tryProtocols(EFI_HANDLE imgh, EFI_SYSTEM_TABLE* syst) {
EFI_LOADED_IMAGE* loaded_image = NULL;
EFI_GUID guid_imgprot = LOADED_IMAGE_PROTOCOL;
tryProtocol(guid_imgprot, (void**)&loaded_image,
L"LOADED_IMAGE_PROTOCOL", imgh, syst);
Print(L"Image base: %lx\n", loaded_image->ImageBase);
Print(L"Image size: %lx\n", loaded_image->ImageSize);
Print(L"Image file: %s\n", DevicePathToStr(loaded_image->FilePath));
EFI_FIRMWARE_MANAGEMENT_PROTOCOL* fw_manage = NULL;
EFI_GUID guid_fwman_prot = EFI_FIRMWARE_MANAGEMENT_PROTOCOL_GUID;
tryProtocol(guid_fwman_prot, (void**)&fw_manage,
L"FIRMWARE_MANAGEMENT_PROTOCOL", imgh, syst);
EFI_LOAD_FILE_PROTOCOL* load_file = NULL;
EFI_GUID guid_loadf_prot = EFI_LOAD_FILE_PROTOCOL_GUID;
tryProtocol(guid_loadf_prot, (void**)&load_file,
L"LOAD_FILE_PROTOCOL", imgh, syst);
EFI_LOAD_FILE2_PROTOCOL* load_file2 = NULL;
EFI_GUID guid_loadf2_prot = EFI_LOAD_FILE2_PROTOCOL_GUID;
tryProtocol(guid_loadf2_prot, (void**)&load_file2,
L"LOAD_FILE2_PROTOCOL", imgh, syst);
EFI_SIMPLE_FILE_SYSTEM_PROTOCOL* simple_fs = NULL;
EFI_GUID guid_simple_fs_prot = EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID;
tryProtocol(guid_simple_fs_prot, (void**)&simple_fs,
L"SIMPLE_FILE_SYSTEM_PROTOCOL", imgh, syst);
EFI_DISK_IO_PROTOCOL* disk = NULL;
EFI_GUID guid_disk_io_prot = EFI_DISK_IO_PROTOCOL_GUID;
tryProtocol(guid_disk_io_prot, (void**)&disk,
L"DISK_IO_PROTOCOL", imgh, syst);
EFI_BLOCK_IO_PROTOCOL* block = NULL;
EFI_GUID guid_block_io_prot = EFI_BLOCK_IO_PROTOCOL_GUID;
tryProtocol(guid_block_io_prot, (void**)&block,
L"BLOCK_IO_PROTOCOL", imgh, syst);
}
EFI_STATUS
EFIAPI
efi_main (EFI_HANDLE imageHandle, EFI_SYSTEM_TABLE* systemTable) {
InitializeLib(imageHandle, systemTable);
Print(L"Image loaded\n");
tryProtocols(imageHandle, systemTable);
return EFI_SUCCESS;
}
Here's the output for running it:
EFI Shell version 2.40 [5.11]
Current running mode 1.1.2
Device mapping table
fs0 :HardDisk - Alias hd6b blk0
PciRoot(0x0)/Pci(0x10,0x0)/Ctrl(0x0)/HD(1,GPT,2DCDDADD-8F3A-4A77-94A9-010A8C700BB8,0x800,0x100000)
fs1 :Removable HardDisk - Alias hd9g0a0b blk1
PciRoot(0x0)/Pci(0x14,0x0)/USB(0x6,0x0)/USB(0x0,0x0)/HD(1,MBR,0x528E6A1F,0x800,0x1CDE800)
blk0 :HardDisk - Alias hd6b fs0
PciRoot(0x0)/Pci(0x10,0x0)/Ctrl(0x0)/HD(1,GPT,2DCDDADD-8F3A-4A77-94A9-010A8C700BB8,0x800,0x100000)
blk1 :Removable HardDisk - Alias hd9g0a0b fs1
PciRoot(0x0)/Pci(0x14,0x0)/USB(0x6,0x0)/USB(0x0,0x0)/HD(1,MBR,0x528E6A1F,0x800,0x1CDE800)
blk2 :HardDisk - Alias (null)
PciRoot(0x0)/Pci(0x10,0x0)/Ctrl(0x0)/HD(2,GPT,8AC0F94E-3CA2-4C03-BE00-3A69721CC391,0x100800,0x1C1F7DF)
blk3 :BlockDevice - Alias (null)
PciRoot(0x0)/Pci(0x10,0x0)/Ctrl(0x0)
blk4 :BlockDevice - Alias (null)
PciRoot(0x0)/Pci(0x10,0x0)/Ctrl(0x1)
blk5 :BlockDevice - Alias (null)
PciRoot(0x0)/Pci(0x10,0x0)/Ctrl(0x2)
blk6 :Removable BlockDevice - Alias (null)
PciRoot(0x0)/Pci(0x14,0x0)/USB(0x6,0x0)/USB(0x0,0x0)
Press ESC in 4 seconds to skip startup.nsh, any other key to continue.
fs1:\> tryprotocols.efi
Image loaded
Protocol LOADED_IMAGE_PROTOCOL is supported
Image base: 55BA6000
Image size: F000
Image file: \/tryprotocols.efi
HandleProtocol error for FIRMWARE_MANAGEMENT_PROTOCOL: Unsupported
HandleProtocol error for LOAD_FILE_PROTOCOL: Unsupported
HandleProtocol error for LOAD_FILE2_PROTOCOL: Unsupported
HandleProtocol error for SIMPLE_FILE_SYSTEM_PROTOCOL: Unsupported
HandleProtocol error for DISK_IO_PROTOCOL: Unsupported
HandleProtocol error for BLOCK_IO_PROTOCOL: Unsupported
fs1:\>
And here's the Makefile I use to compile it:
ARCH=x86_64
OBJS=tryprotocols.o
TARGET=tryprotocols.efi
TARGET_SO=$(TARGET:.efi=.so)
GNUEFIDIR=/home/gekko/gnu-efi-3.0.8
EFIINC=$(GNUEFIDIR)/inc
EFIINCS=-I$(EFIINC) -I$(EFIINC)/$(ARCH) -I$(EFIINC)/protocol
LIB=$(GNUEFIDIR)/$(ARCH)/lib
EFILIB=$(GNUEFIDIR)/gnuefi
EFI_CRT_OBJS=$(GNUEFIDIR)/$(ARCH)/gnuefi/crt0-efi-$(ARCH).o
EFI_LDS=$(EFILIB)/elf_$(ARCH)_efi.lds
CFLAGS=$(EFIINCS) -fno-stack-protector -fpic \
-fshort-wchar -mno-red-zone -Wall
ifeq ($(ARCH),x86_64)
CFLAGS += -DEFI_FUNCTION_WRAPPER
endif
LDFLAGS=-nostdlib -znocombreloc -T $(EFI_LDS) -shared \
-Bsymbolic -L $(EFILIB) -L $(LIB) $(EFI_CRT_OBJS)
all: $(TARGET)
$(TARGET_SO): $(OBJS)
ld $(LDFLAGS) $(OBJS) -o $# -lefi -lgnuefi
%.efi: %.so
objcopy -j .text -j .sdata -j .data -j .dynamic \
-j .dynsym -j .rel -j .rela -j .reloc \
--target=efi-app-$(ARCH) $^ $#
clean:
rm -f *.o
rm -f $(TARGET)
rm -f $(TARGET_SO)
EDIT: Modified version that properly uses LocateProtocol() to find the protocols, and uses them to open and close a file.
#include <efi.h>
#include <efilib.h>
#include <x86_64/efibind.h>
BOOLEAN tryProtocol(EFI_GUID proto_guid, void** out, const CHAR16* name,
EFI_HANDLE imageHandle, EFI_SYSTEM_TABLE* systemTable) {
*out = NULL;
EFI_STATUS status;
EFI_HANDLE interface = NULL;
status = uefi_call_wrapper(systemTable->BootServices->LocateProtocol, 3,
&proto_guid, NULL, &interface);
if (EFI_ERROR(status)) {
Print(L"LocateProtocol error for %s: %r\n", name, status);
return FALSE;
}
Print(L"Locate protocol address: %s, %x\n", name, interface);
*out = interface;
return TRUE;
}
EFI_STATUS
EFIAPI
efi_main (EFI_HANDLE imageHandle, EFI_SYSTEM_TABLE* systemTable) {
InitializeLib(imageHandle, systemTable);
Print(L"Image loaded\n");
EFI_LOADED_IMAGE* loaded_image = NULL;
EFI_GUID guid_imgprot = LOADED_IMAGE_PROTOCOL;
if (tryProtocol(guid_imgprot, (void**)&loaded_image,
L"LOADED_IMAGE_PROTOCOL", imageHandle, systemTable) != TRUE) {
Print(L"Missing required protocol. Aborting\n");
return EFI_SUCCESS;
}
Print(L"Image base: %lx\n", loaded_image->ImageBase);
Print(L"Image size: %lx\n", loaded_image->ImageSize);
Print(L"Image file: %s\n", DevicePathToStr(loaded_image->FilePath));
EFI_SIMPLE_FILE_SYSTEM_PROTOCOL* simple_fs = NULL;
EFI_GUID guid_simple_fs_prot = EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID;
if (tryProtocol(guid_simple_fs_prot, (void**)&simple_fs,
L"EFI_SIMPLE_FILE_SYSTEM_PROTOCOL", imageHandle, systemTable) != TRUE) {
Print(L"Missing required protocol. Aborting\n");
return EFI_SUCCESS;
}
EFI_FILE_PROTOCOL* vol_proto = NULL;
EFI_STATUS status;
Print(L"dereffing\n");
Print(L"address of OpenVolume: %x\n", simple_fs->OpenVolume);
status = uefi_call_wrapper(simple_fs->OpenVolume, 2, simple_fs, &vol_proto);
if (EFI_ERROR(status)) {
Print(L"Error opening volume: %r\n", status);
return EFI_SUCCESS;
}
Print(L"SIMPLE_FILE_SYSTEM volume opened\n");
EFI_FILE_PROTOCOL* f;
CHAR16 fname[10] = L"foo.txt\0";
UINT64 openmode = EFI_FILE_MODE_READ;
UINT64 attr = 0;
status = uefi_call_wrapper(vol_proto->Open, 5, vol_proto, &f, fname, openmode, attr);
if (EFI_ERROR(status)) {
Print(L"Error opening file: %r\n", status);
return EFI_SUCCESS;
}
Print(L"opened file %s\n", fname);
// Spec says can only return EFI_SUCCESS
status = uefi_call_wrapper(vol_proto->Close, 1, f);
Print(L"Closed file\n");
return EFI_SUCCESS;
}
Where and how to access a specific protocol is not statically defined by the UEFI specification, but something that needs to be discovered at runtime. While a bit arduous, it makes it possible to write applications/drivers portable across vastly different UEFI implementations that all conform to the specification.
So you need to LocateProtocol() on each protocol you are intending to use before you can make use of HandleProtocol().
You get away with LOADED_IMAGE_PROTOCOL because that one is initialized with your ImageHandle referring to the instance of the currently executing image (your program).
This is covered in Matthew's post under the section That covers how to use protocols attached to the image handle. How about protocols that are attached to other handles?.