Quoting the UEFI specifications section about EFI_BOOT_SERVICES.HandleProtocol():
The HandleProtocol() function is still available for use by old EFI
applications and drivers. However, all new applications and drivers
should use EFI_BOOT_SERVICES.OpenProtocol() in place of
HandleProtocol(). The following code fragment shows a possible
implementation of HandleProtocol() using OpenProtocol(). The variable
EfiCoreImageHandle is the image handle of the EFI core.
EFI_STATUS
HandleProtocol (
IN EFI_HANDLE Handle,
IN EFI_GUID *Protocol,
OUT VOID **Interface
)
{
return OpenProtocol (
Handle,
Protocol,
Interface,
EfiCoreImageHandle,
NULL,
EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL
);
}
End of quote.
My question is: how to get the value for EfiCoreImageHandle when an EFI application was run by a boot manager, or from a UEFI shell?
Simply put, EfiCoreImageHandle is just a placeholder in the specification. Have a look at how I invoke OpenProtocol in the ShowEDID utility in https://github.com/fpmurphy/UEFI-Utilities-2019.
Also look at the ShowUSB utility where I currently use HandleProtocol, i.e.
Status = gBS->HandleProtocol( HandleBuffer[Index],
&gEfiUsbIoProtocolGuid,
(VOID**)&UsbIo );
I could replace the above code with:
Status = gBS->OpenProtocol( HandleBuffer[Index],
&gEfiUsbIoProtocolGuid,
(VOID **)&UsbIo,
gImageHandle,
NULL,
EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL );
Tested with UDK2018 and Lenovo T480
Related
Is it possible to open Windows' settings dialogs using Win32 API calls from C? Such as the monitor settings (the one that allows you to set the monitor's resolution), and the network settings (the one that allows you to set the Wifi settings).
If it is possible, how to do that?
Or, is this not possible at all, and the user has to manually open them?
Launch the Windows Settings app explains how to pull up the Windows Settings app using the ms-settings: URI scheme. It also lists the supported URIs, including the ones this question is asking for (ms-settings:network-wifi and ms-settings:display).
While the documentation proposes using the Windows Runtime API Launcher.LaunchUriAsync this is a fair bit complex with C (as opposed to C++). Since the URIs can be invoked from the command prompt using the start command (e.g. start ms-settings:display), it's reasonable to assume that ShellExecuteExW can handle the ms-settings: URI scheme as well.
And indeed, this does appear to work:
#include <Windows.h>
#include <stdio.h>
int main() {
SHELLEXECUTEINFOW sei = {
.cbSize = sizeof(sei),
.hwnd = NULL,
.lpVerb = L"open",
.lpFile = L"ms-settings:display",
//.lpFile = L"ms-settings:network-wifi",
.nShow = SW_SHOWNORMAL,
};
if (!ShellExecuteExW(&sei))
{
printf("Failed with error code %d", GetLastError());
}
}
I wasn't able to find any documentation that specifies this behavior, so this may well be an unsupported implementation detail. I will also mention that while SHELLEXECUTEINFOW has an lpClass field that can be used to specify a URI protocol scheme, none of my iterations to use it worked for the ms-settings: URI scheme.
I would like to get a list of the wireless networks available. Ideally this would be via some C call, but I don't mind if I have to kludge it with a system call. Even better if the required C call or program doesn't require some exotic 3rd party package.
The internet seems to suggest I use sudo iwlist <interface> scan which does seem to do the trick from the command line, but I'd rather not require root permissions. I only want to see the basics, not change anything.
It's pretty easy to do a scan in the command line. The man pages are your friend here (check out iwconfig and iwlist). But using the C interface is a little more difficult so I'll focus on that.
First of all, as other people have mentioned, definitely download out the wireless tools source code. All the documentation for the programming interface is in the .c files. As far as I can tell, there is no web documentation for the api. However, the source code is pretty easy to read through. You pretty much only need iwlib.h and iwlib.c for this question.
While you can use iw_set_ext and iw_get_ext, the libiw implements a basic scanning function iw_scan, from which you can extract most of the information that you need.
Here is a simple program to get the ESSID for all available wireless networks. Compile with -liw and run with sudo.
#include <stdio.h>
#include <time.h>
#include <iwlib.h>
int main(void) {
wireless_scan_head head;
wireless_scan *result;
iwrange range;
int sock;
/* Open socket to kernel */
sock = iw_sockets_open();
/* Get some metadata to use for scanning */
if (iw_get_range_info(sock, "wlan0", &range) < 0) {
printf("Error during iw_get_range_info. Aborting.\n");
exit(2);
}
/* Perform the scan */
if (iw_scan(sock, "wlan0", range.we_version_compiled, &head) < 0) {
printf("Error during iw_scan. Aborting.\n");
exit(2);
}
/* Traverse the results */
result = head.result;
while (NULL != result) {
printf("%s\n", result->b.essid);
result = result->next;
}
exit(0);
}
DISCLAIMER: This is just a demonstration program. It's possible for some results to not have an essid. In addition, this assumes your wireless interface is "wlan0". You get the idea.
Read the iwlib source code!
The Wireless Tools package -- of which iwlist is a part -- also contains a Wireless Tools Helper Library. You need to include iwlib.h and link with libiw.a (i.e. add -liw). Then look up the documentation for the iw_set_ext function. The SIOCSIWSCAN parameter will be of most use. For an example of how to use this interface, take a look at the KWifiManager source in the KDE library (see: Interface_wireless_wirelessextensions::get_available_networks method). Alternatively, you can also download the Wireless Tools source code and take a look at how the iwlib iw_set_ext function is also used for scanning in iwlist.c.
As for privileges, I imagine the process will need to run as root to perform the scan. I'd love to know if this could be done otherwise as well.
Since you are using Ubuntu 8.04 the libiw-dev package should be of use.
You can use nmcli which does not require root permissions or name of WIFI interface.
nmcli -t -f ssid dev wifi
I try get IShellItem for a file to copy it with IFileOperation COM interface from system directory to another directory. I must use exactly IFileOperation COM interface for this purpose.
When I specify full filename - return value from SHCreateItemFromParsingName() was ERROR_FILE_NOT_FOUND, but file present in the directory. When I delete filename from path below and use only folder path - all seems good, return value is S_OK.
//...
CoInitialize(NULL);
//...
WCHAR szSourceDll[MAX_PATH * 2];
wcscpy_s(szSourceDll, MAX_PATH, L"C:\\Windows\\System32\\sysprep\\cryptbase.dll");
r = CoCreateInstance(&CLSID_FileOperation, NULL, CLSCTX_INPROC_SERVER | CLSCTX_LOCAL_SERVER | CLSCTX_INPROC_HANDLER, &IID_IFileOperation, &FileOperation1);
if (r != S_OK) return;
FileOperation1->lpVtbl->SetOperationFlags(FileOperation1, FOF_NOCONFIRMATION | FOFX_NOCOPYHOOKS | FOFX_REQUIREELEVATION);
r = SHCreateItemFromParsingName(szSourceDll, NULL, &IID_IShellItem, &isrc);
//...
CoUninitialize();
//...
Why this code, written in C, not working with filenames. How can I create IShellItem instance for file in system folder to copy it?
P.S.
Windows 7 x64, C, Visual Studio 2015, v140 platform toolset, additional dependencies: Msi.lib;Wuguid.lib;ole32.lib;ntdll.lib
P.P.S
It's properly work with files in user`s directories...
Assuming your application is compiled as a 32-bit application and running on a 64-bit OS, a file not found error is probably correct because your application is redirected to the 32-bit system directory (%WinDir%\SysWoW64).
In most cases, whenever a 32-bit application attempts to access %windir%\System32, %windir%\lastgood\system32, or %windir%\regedit.exe, the access is redirected to an architecture-specific path.
For more information, see File System Redirector on MSDN.
You could temporarily turn off redirection in your thread but it is not really safe to do this when calling shell functions, only functions in kernel32. If the API you are calling internally uses LoadLibrary and/or COM then the API might fail because it will be unable to load from system32 while redirection is disabled.
You can also access the native system32 directory with the %WinDir%\SysNative backdoor. This only works in 32-bit applications on 64-bit Vista+ so you must do some version detection.
Is there a way to close the device/socket in VxWorks programmatically?
Meaning say I have the devices /tyco/0, /tyco/1 and /tyco/2 and I want to close/shutdown /tyco/1 and /tyco/2.
I would like to do something like remove("/tyco/1"). Something that would prevent even an open("/tyco/1") call later on in the code or from an outside source from opening the socket.
All devices available to VxWorks are part of the device list. The device list is accessible using the iosLib.
I've used the following code a lot to remove devices to generate errors in order to test my programs:
DEV_HDR *pDevice;
pDevice = iosDevFind("/xyz", NULL);
if (pDevice != NULL)
{
iosDevDelete(pDevice);
}
This works for all devices listed by the devs command which in your case will also work for "/tyco". I doubt that you can inhibit open calls to "/tyco/1" and "/tyco/2" but allow calls to "/tyco/0" using that method since it works on "devices".
If "/tyco/0" is your serial interface to the VxWorks shell then the method from above will work. Because removing a device from the device list will cause all following open calls to that device to fail but will not close already opened devices...
Problem: I have to configure various LCD displays to be used by Android Platform. Almost in all cases there are no electrical specifications freely available for LCD displays on interest. But through experience and reverse engineering the parameters can be guessed reasonably well. I am trying to use Loadable Kernel Modules to fine tune the display parameters (any other suggestions are welcome too). Please find the relevant information below.
HW: Atmel SAMA5D31-EK (ARM 5 processor)
SW: Andriod Linux (Target), Ubuntu (Host System), Sourcery CodeBench (Cross Compiler)
Code Snippets from board-dt.c file
static struct fb_videomode at91_tft_vga_modes[] = {
.....
.xres =435;
.yres =235;
....
}
static struct fb_monspecs at91fb_default_monspecs = {
.........
.modedb = at91_tft_vga_modes,
......
}
static struct atmel_lcd_fb_info __initdata ek_lcdc_data = {
..........
.default_monspecs = & at91fb_default_monspecs;
.........
}
I added this code so the Loadable Kernel Module has access to lcdc_data structure
extern void set_fb_video(struct fb_videomode *mg_set_tft_vga_modes)
{
ek_lcdc_data.default_monspecs->modedb->xres = mg_set_tft_vga_modes->xres;
}
EXPORT_SYMBOL(set_fb_video);
When I execute the loadable kernel module I don’t notice any change in the display. I suspect although I am changing the variable (memory) but registers are not been affected.
Question: What am I missing? I have read about making calls to platform_driver_register() and platform_driver_unregister().
Thank you for your help in advance.