I would like to know how to use the Invoke method of the TRttiMethod class in C++Builder 2010.
This is my code
Tpp *instance=new Tpp(this);
TValue *args;
TRttiContext * ctx=new TRttiContext();
TRttiType * t = ctx->GetType(FindClass(instance->ClassName()));
TRttiMethod *m=t->GetMethod("Show");
m->Invoke(instance,args,0);
Show has no arguments and it is __published. When I execute I get a EInvocationError with message 'Parameter count mismatch'.
Can someone demonstrate the use of Invoke? Both no arguments and with arguments in the called method.
Thanks
Josep
You get the error because you are telling Invoke() that you are passing in 1 method parameter (even though you really are not, but that is a separate bug in your code). Invoke() takes an OPENARRAY of TValue values as input. Despite its name, the Args_Size parameter is not the NUMBER of parameters being passed in, but rather is the INDEX of the last parameter in the array. So, to pass 0 method parameters to Show() via Invoke(), set the Args parameter to NULL and the Args_Size parameter to -1 instead of 0, ie:
Tpp *instance = new Tpp(this);
TRttiContext *ctx = new TRttiContext;
TRttiType *t = ctx->GetType(instance->ClassType());
TRttiMethod *m = t->GetMethod("Show");
m->Invoke(instance, NULL, -1);
delete ctx;
Now, once you fix that, you will notice Invoke() start to raise an EInsufficientRtti exception instead. That happens when Runtime Packages are enabled. Unfortunately, disabling Runtime Packages will cause TRttiContext::GetType() to raise an EAccessViolation in TRttiPool::GetPackageFor() because of a known linker bug under C++:
QC #76875, RAID #272782: InitContext.PackageTypeInfo shouldn't be 0 in a C++ module:
Which causes these bugs:
QC #76672, RAID #272419: Rtti.pas is unusable in a C++ application
QC #76877, RAID #272767: AV in TRttiContext::GetType() when Runtime Packages are disabled
So you are in a catch-22 situation. The new RTTI system is not ready for production work in C++ yet. You will have to use Delphi instead for the time being.
Related
how can I Print adittional information to Command line Console?
Output now is:
C:\Users\admin\Desktop\java>java -jar pdf.jar
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Index 0 out of bounds for length 0
at readDataIn.main(readDataIn.java:31)
Code:
public static void main(String[] args) throws IOException {
// TODO Auto-generated method stub
try {
String arg = args[0];
fileNameSource = "import/" + arg + ".xml";
fileNameTarget = "export/" + arg + ".pdf";
} catch (Exception e) {
// TODO: handle exception
**System.out.println("Personal-Number is missing");**
e.printStackTrace();
}
How can i give the information out, that the Personal Number ist Missing?
First of all, as a general rule you should check for possible exceptions before they actually occur if that is possible, which in your case it definitely is.
So instead of catching the ArrayIndexOutOfBounds insert an if statement that checks the length of the args array before accessing it.
if(args.length == 0){
// no argument has been provided
// handle error here
}
In terms of how to handle the error, there are many options available and depending of what you want to do either could be a good fit.
IllegalArgumentException
It is a common idiom in Java that whenever a function receives an invalid/ illegal argument to throw an IllegalArgumentException.
if (args.length == 0){
throw new IllegalArgumentException("Personal number is missing");
}
This will print the message that you have provided and the stack trace. However if your application should be a Command Line Interface (CLI) you should not use this kind of error handling.
Print message & exit program
if (args.length == 0){
// notice: "err" instead of "out": print to stderr instead of stdout
System.err.println("Personal number is missing");
// exit program with non-zero exit code as exit code == 0 means everything is fine
System.exit(1);
}
For more information on stdout and stderr see this StackOverflow question.
This is what many CLI applications and e.g. java itself does. When you type java fdsdfsdfs or some similar nonsense as an argument Java will give you an error message and exit with some non-zero return code ("1" in this case).
It is also common that CLI applications print an error message and following some usage information on how to correctly use the application or provide a help command so a user can get more information. This happens for example if you just enter java without any parameters.
So it is really up to you what you want to do.
If you are thinking of implementing a full featured CLI application with more (complex) commands with multiple options etc. you should consider using a CLI library like JCommander or Apache Commons CLI as parsing command line arguments can quickly get ugly. All these common things are already handled there.
Logging
In case your application is some script that will be executed in a non-interactive way logging the error to a file and exiting with a non-zero exit code might also be an option.
PS
Your code looks to me like it should not compile at all as you are not declaring a type for your variables fileNameSource and fileNameTarget.
Use String or var here (assuming you're running > Java 11).
String fileNameSource = "import/" + arg + ".xml";
var fileNameTarget = "export/" + arg + ".pdf";
You might also need to consider that your program name is part of the args array, so you might have more than 0 values in the array and therefore might need to adjust the if statements above.
You may be interested in picocli, which is a modern CLI library for Java and other JVM languages.
Picocli does some basic validation automatically, and results in very compact code that produces user-friendly applications. For example:
import picocli.CommandLine;
import picocli.CommandLine.Command;
import picocli.CommandLine.Option;
import picocli.CommandLine.Parameters;
#Command(name = "myapp", mixinStandardHelpOptions = true, version = "1.0",
description = "This command does something useful.")
class MyApp implements Runnable {
#Parameters(description = "File name (without extension) of the file to import and export.")
private String personalNumber;
#Override
public void run() {
String fileNameSource = "import/" + personalNumber + ".xml";
String fileNameTarget = "export/" + personalNumber + ".pdf";
// remaining business logic
}
public static void main(String[] args) {
System.exit(new CommandLine(new MyApp()).execute(args));
}
}
If I run this class without any parameters, the following message is printed to the standard error stream, and the process finished with exit code 2. (Exit codes are customizable.)
Missing required parameter: '<personalNumber>'
Usage: myapp [-hV] <personalNumber>
This command does something useful.
<personalNumber> File name (without extension) of the file to import
and export.
-h, --help Show this help message and exit.
-V, --version Print version information and exit.
The usage help message is created automatically from the descriptions of the command, and the descriptions of its options and positional parameters, but can be further customized.
Note how the mixinStandardHelpOptions = true annotation adds --help and --version options to the command. These options are handled by the library without requiring any further logic in the application.
Picocli comes with an annotation processor that makes it very easy to turn your application into a native image with GraalVM. Native images have faster startup time and lower runtime memory overhead compared to a Java VM.
EDIT:
I have heavily edited this question after making some significant new discoveries and the question not having any answers yet.
Historically/AFAIK, keeping your Mac awake while in closed-display mode and not meeting Apple's requirements, has only been possible with a kernel extension (kext), or a command run as root. Recently however, I have discovered that there must be another way. I could really use some help figuring out how to get this working for use in a (100% free, no IAP) sandboxed Mac App Store (MAS) compatible app.
I have confirmed that some other MAS apps are able to do this, and it looks like they might be writing YES to a key named clamshellSleepDisabled. Or perhaps there's some other trickery involved that causes the key value to be set to YES? I found the function in IOPMrootDomain.cpp:
void IOPMrootDomain::setDisableClamShellSleep( bool val )
{
if (gIOPMWorkLoop->inGate() == false) {
gIOPMWorkLoop->runAction(
OSMemberFunctionCast(IOWorkLoop::Action, this, &IOPMrootDomain::setDisableClamShellSleep),
(OSObject *)this,
(void *)val);
return;
}
else {
DLOG("setDisableClamShellSleep(%x)\n", (uint32_t) val);
if ( clamshellSleepDisabled != val )
{
clamshellSleepDisabled = val;
// If clamshellSleepDisabled is reset to 0, reevaluate if
// system need to go to sleep due to clamshell state
if ( !clamshellSleepDisabled && clamshellClosed)
handlePowerNotification(kLocalEvalClamshellCommand);
}
}
}
I'd like to give this a try and see if that's all it takes, but I don't really have any idea about how to go about calling this function. It's certainly not a part of the IOPMrootDomain documentation, and I can't seem to find any helpful example code for functions that are in the IOPMrootDomain documentation, such as setAggressiveness or setPMAssertionLevel. Here's some evidence of what's going on behind the scenes according to Console:
I've had a tiny bit of experience working with IOMProotDomain via adapting some of ControlPlane's source for another project, but I'm at a loss for how to get started on this. Any help would be greatly appreciated. Thank you!
EDIT:
With #pmdj's contribution/answer, this has been solved!
Full example project:
https://github.com/x74353/CDMManager
This ended up being surprisingly simple/straightforward:
1. Import header:
#import <IOKit/pwr_mgt/IOPMLib.h>
2. Add this function in your implementation file:
IOReturn RootDomain_SetDisableClamShellSleep (io_connect_t root_domain_connection, bool disable)
{
uint32_t num_outputs = 0;
uint32_t input_count = 1;
uint64_t input[input_count];
input[0] = (uint64_t) { disable ? 1 : 0 };
return IOConnectCallScalarMethod(root_domain_connection, kPMSetClamshellSleepState, input, input_count, NULL, &num_outputs);
}
3. Use the following to call the above function from somewhere else in your implementation:
io_connect_t connection = IO_OBJECT_NULL;
io_service_t pmRootDomain = IOServiceGetMatchingService(kIOMasterPortDefault, IOServiceMatching("IOPMrootDomain"));
IOServiceOpen (pmRootDomain, current_task(), 0, &connection);
// 'enable' is a bool you should assign a YES or NO value to prior to making this call
RootDomain_SetDisableClamShellSleep(connection, enable);
IOServiceClose(connection);
I have no personal experience with the PM root domain, but I do have extensive experience with IOKit, so here goes:
You want IOPMrootDomain::setDisableClamShellSleep() to be called.
A code search for sites calling setDisableClamShellSleep() quickly reveals a location in RootDomainUserClient::externalMethod(), in the file iokit/Kernel/RootDomainUserClient.cpp. This is certainly promising, as externalMethod() is what gets called in response to user space programs calling the IOConnectCall*() family of functions.
Let's dig in:
IOReturn RootDomainUserClient::externalMethod(
uint32_t selector,
IOExternalMethodArguments * arguments,
IOExternalMethodDispatch * dispatch __unused,
OSObject * target __unused,
void * reference __unused )
{
IOReturn ret = kIOReturnBadArgument;
switch (selector)
{
…
…
…
case kPMSetClamshellSleepState:
fOwner->setDisableClamShellSleep(arguments->scalarInput[0] ? true : false);
ret = kIOReturnSuccess;
break;
…
So, to invoke setDisableClamShellSleep() you'll need to:
Open a user client connection to IOPMrootDomain. This looks straightforward, because:
Upon inspection, IOPMrootDomain has an IOUserClientClass property of RootDomainUserClient, so IOServiceOpen() from user space will by default create an RootDomainUserClient instance.
IOPMrootDomain does not override the newUserClient member function, so there are no access controls there.
RootDomainUserClient::initWithTask() does not appear to place any restrictions (e.g. root user, code signing) on the connecting user space process.
So it should simply be a case of running this code in your program:
io_connect_t connection = IO_OBJECT_NULL;
IOReturn ret = IOServiceOpen(
root_domain_service,
current_task(),
0, // user client type, ignored
&connection);
Call the appropriate external method.
From the code excerpt earlier on, we know that the selector must be kPMSetClamshellSleepState.
arguments->scalarInput[0] being zero will call setDisableClamShellSleep(false), while a nonzero value will call setDisableClamShellSleep(true).
This amounts to:
IOReturn RootDomain_SetDisableClamShellSleep(io_connect_t root_domain_connection, bool disable)
{
uint32_t num_outputs = 0;
uint64_t inputs[] = { disable ? 1 : 0 };
return IOConnectCallScalarMethod(
root_domain_connection, kPMSetClamshellSleepState,
&inputs, 1, // 1 = length of array 'inputs'
NULL, &num_outputs);
}
When you're done with your io_connect_t handle, don't forget to IOServiceClose() it.
This should let you toggle clamshell sleep on or off. Note that there does not appear to be any provision for automatically resetting the value to its original state, so if your program crashes or exits without cleaning up after itself, whatever state was last set will remain. This might not be great from a user experience perspective, so perhaps try to defend against it somehow, for example in a crash handler.
Background
It is possible to perform a software-controlled disconnection of the power adapter of a Mac laptop by creating an DisableInflow power management assertion.
Code from this answer to an SO question can be used to create said assertion. The following is a working example that creates this assertion until the process is killed:
#include <IOKit/pwr_mgt/IOPMLib.h>
#include <unistd.h>
int main()
{
IOPMAssertionID neverSleep = 0;
IOPMAssertionCreateWithName(kIOPMAssertionTypeDisableInflow,
kIOPMAssertionLevelOn,
CFSTR("disable inflow"),
&neverSleep);
while (1)
{
sleep(1);
}
}
This runs successfully and the power adapter is disconnected by software while the process is running.
What's interesting, though, is that I was able to run this code as a regular user, without root privileges, which wasn't supposed to happen. For instance, note the comment in this file from Apple's open source repositories:
// Disables AC Power Inflow (requires root to initiate)
#define kIOPMAssertionTypeDisableInflow CFSTR("DisableInflow")
#define kIOPMInflowDisableAssertion kIOPMAssertionTypeDisableInflow
I found some code which apparently performs the actual communication with the charger; it can be found here. The following functions, from this file, appears to be of particular interest:
IOReturn
AppleSmartBatteryManagerUserClient::externalMethod(
uint32_t selector,
IOExternalMethodArguments * arguments,
IOExternalMethodDispatch * dispatch __unused,
OSObject * target __unused,
void * reference __unused )
{
if (selector >= kNumBattMethods) {
// Invalid selector
return kIOReturnBadArgument;
}
switch (selector)
{
case kSBInflowDisable:
// 1 scalar in, 1 scalar out
return this->secureInflowDisable((int)arguments->scalarInput[0],
(int *)&arguments->scalarOutput[0]);
break;
// ...
}
// ...
}
IOReturn AppleSmartBatteryManagerUserClient::secureInflowDisable(
int level,
int *return_code)
{
int admin_priv = 0;
IOReturn ret = kIOReturnNotPrivileged;
if( !(level == 0 || level == 1))
{
*return_code = kIOReturnBadArgument;
return kIOReturnSuccess;
}
ret = clientHasPrivilege(fOwningTask, kIOClientPrivilegeAdministrator);
admin_priv = (kIOReturnSuccess == ret);
if(admin_priv && fOwner) {
*return_code = fOwner->disableInflow( level );
return kIOReturnSuccess;
} else {
*return_code = kIOReturnNotPrivileged;
return kIOReturnSuccess;
}
}
Note how, in secureInflowDisable(), root privileges are checked for prior to running the code. Note also this initialization code in the same file, again requiring root privileges, as explicitly pointed out in the comments:
bool AppleSmartBatteryManagerUserClient::initWithTask(task_t owningTask,
void *security_id, UInt32 type, OSDictionary * properties)
{
uint32_t _pid;
/* 1. Only root processes may open a SmartBatteryManagerUserClient.
* 2. Attempts to create exclusive UserClients will fail if an
* exclusive user client is attached.
* 3. Non-exclusive clients will not be able to perform transactions
* while an exclusive client is attached.
* 3a. Only battery firmware updaters should bother being exclusive.
*/
if ( kIOReturnSuccess !=
clientHasPrivilege(owningTask, kIOClientPrivilegeAdministrator))
{
return false;
}
// ...
}
Starting from the code from the same SO question above (the question itself, not the answer), for the sendSmartBatteryCommand() function, I wrote some code that calls the function passing kSBInflowDisable as the selector (the variable which in the code).
Unlike the code using assertions, this one only works as root. If running as a regular user, IOServiceOpen() returns, weirdly enough, kIOReturnBadArgument (not kIOReturnNotPrivileged, as I would have expected). Perhaps this has to do with the initWithTask() method above.
The question
I need to perform a call with a different selector to this same Smart Battery Manager kext. Even so, I can't even get to the IOConnectCallMethod() since IOServiceOpen() fails, presumably because the initWithTask() method prevents any non-root users from opening the service.
The question, therefore, is this: how is IOPMAssertionCreateWithName() capable of creating a DisableInflow assertion without root privileges?
The only possibility I can think of is if there's a root-owned process to which requests are forwarded, and which performs the actual work of calling IOServiceOpen() and later IOConnectCallMethod() as root.
However, I'm hoping there's a different way of calling the Smart Battery Manager kext which doesn't require root (one that doesn't involve the IOServiceOpen() call.) Using IOPMAssertionCreateWithName() itself is not possible in my application, since I need to call a different selector within that kext, not the one that disables inflow.
It's also possible this is in fact a security vulnerability, which Apple will now fix in a future release as soon as it is alerted to this question. That would be too bad, but understandable.
Although running as root is a possibility in macOS, it's obviously desirable to avoid privilege elevation unless absolutely necessary. Also, in the future I'd like to run the same code under iOS, where it's impossible to run anything as root, in my understanding (note this is an app I'm developing for my own personal use; I understand linking to IOKit wipes out any chance of getting the app published in the App Store).
I'm having a problem with ChangeServiceConfig2(...SERVICE_CONFIG_TRIGGER_INFO...)
Relevant code:
WCHAR test[] = L"TEST12";
SERVICE_TRIGGER_SPECIFIC_DATA_ITEM stdata {
SERVICE_TRIGGER_DATA_TYPE_STRING,
wcslen(test)*sizeof(WCHAR),
reinterpret_cast<BYTE*>(test)
};
SERVICE_TRIGGER st {
SERVICE_TRIGGER_TYPE_NETWORK_ENDPOINT,
SERVICE_TRIGGER_ACTION_SERVICE_START,
const_cast<GUID*>(&NAMED_PIPE_EVENT_GUID),
1, &stdata
};
ChangeServiceConfig2(Service, SERVICE_CONFIG_TRIGGER_INFO, &st);
This causes an Access Violation on address 00000009, so clearly an unchecked null pointer. And it's not a null pointer in st or stdata. The address 00000009 does not depend on the length of test[].
Stack dump:
rpcrt4.dll!NdrpEmbeddedRepeatPointerBufferSize()
rpcrt4.dll!NdrConformantArrayBufferSize()
rpcrt4.dll!NdrSimpleStructBufferSize()
rpcrt4.dll!NdrpUnionBufferSize()
rpcrt4.dll!_NdrNonEncapsulatedUnionBufferSize#12()
rpcrt4.dll!NdrComplexStructBufferSize()
rpcrt4.dll!NdrClientCall2() rpcrt4.dll!_NdrClientCall4()
sechost.dll!ChangeServiceConfig2W()
The Service member is not the problem, or ChangeServiceConfig2 itself: I can set the service description via ChangeServiceConfig2(Service, SERVICE_CONFIG_DESCRIPTION, &desc);. The problem appears to be in the parsing of SERVICE_TRIGGER. Named Pipe service triggers apparently work for the Remote Registry service, so it's not fundamentally broken.
Q: which part of my SERVICE_TRIGGER is wrong?
Obviously there is at least one bug in Windows; at the very least it fails in parameter validation.
The SERVICE_TRIGGER object is correct, but ChangeServiceConfig2 wants a SERVICE_TRIGGER_INFO. Simple solution: wrap st using SERVICE_TRIGGER_INFO sti{ 1, &st, NULL };
I'm trying to change the value of a flag in an IPropertyStore. However, my code seems to behave the same way, regardless of the value of the flag.
Is this because my code doesn't call IPropertyStore_Commit after changing the flag?
I did try to call the method, however I got an error code 0x80004001 which means "not implemented". Hence, the second part of my question: why isn't it implemented?
In more detail, I'm working on a Java softphone which makes use of WASAPI (via the JNI) for some of the audio processing. The native code is written in C.
Having recently enabled AES (Acoustic Echo Suppression), I've found that AGC (Automatic Gain Control) is also enabled. I'm trying to disable AGC by setting the MFPKEY_WMAAECMA_FEATR_AGC key on an IPropertyStore object. However, whatever I set the value to be makes no difference.
The relevant code snippets are as follows:
// Obtain the property store
void *pvObject;
HRESULT hr = IMediaObject_QueryInterface((IMediaObject *) thiz, &iid_, &pvObject);
// Do some checking that the store is valid...
// Set the value of the AGC key:
PROPVARIANT propvar = ...
IPropertyStore_SetValue((IPropertyStore *)pvObject, (REFPROPERTYKEY) key, &propvar);
// Call commit - fails, with 0x80004001:
HRESULT hr = IPropertyStore_Commit((IPropertyStore *)pvObject);
A couple of issues:
I'm not sure what thiz actually is; I'm pretty sure it's not an IMediaObject interface.
You can't just cast from IMediaObject to IPropertyStore; you have to QueryInterface the IMediaObject pointer for IPropertyStore.
You shouldn't need to call IPropertyStore_Commit; at least, not for setting the AGC key.
When you're calling IPropertyStore_SetValue, make sure the PROPVARIANT is initialized correctly. MFPKEY_WMAAECMA_FEATR_AGC is a BOOLEAN property, so your code needs to look something like this:
IMediaObject *pvObject;
HRESULT hr = IUnknown_QueryInterface((IUnknown*) thiz, IID_PPV_ARGS(&pvObject));
if (SUCCEEDED(hr))
{
IPropertyStore* pvPropStore;
hr = IMediaObject_QueryInterface(pvObject, IID_PPV_ARGS(&pvPropStore));
if (SUCCEEDED(hr))
{
PROPVARIANT pvFeature;
PropVariantInit(&pvFeature);
pvFeature.vt = VT_BOOL;
pvFeature.boolVal = fValue ? VBTRUE : VBFALSE;
hr = IPropertyStore_SetValue(pvPropStore, MFPKEY_WMAAECMA_FEATR_AGC, pvFeature);
}
}