How do I initialize a pointer to a specific C struct? #56
Comments
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I don't think there is a (nice) way. Can you use a Swift script instead? This is not working but it's close, and can't be run in sandboxed Swift app. Fix #!/usr/bin/env swift
import Darwin
let handle = dlopen("/usr/lib/libc.dylib", RTLD_NOW)
let proc_pidinfoSym = dlsym(handle, "proc_pidinfo")
typealias proc_pidinfoFunc = @convention(c) (_ x: CInt, _ y: CInt, _ z: CInt, _ q: UnsafeMutablePointer<SomeTypeHere>, _ r: CInt) -> CInt
let proc_pidinfo = unsafeBitCast(proc_pidinfoSym, to: proc_pidinfoFunc.self)
let pids = ...
var pidInfo: CInt = 0
let infoSize = proc_pidinfo(Int32(pids[0]), PROC_PIDTBSDINFO, 0, &pidInfo, 32)
print(infoSize) |
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This can be done with #!/usr/bin/env osascript -l JavaScript
ObjC.import('Cocoa')
ObjC.import('stdlib')
let pids = [145]
ObjC.bindFunction('malloc', ['void*', ['int']])
let pidInfo = $.malloc(2000)
ObjC.bindFunction('proc_pidinfo', ['int',['int', 'int', 'Int64', 'void *', 'int']]);
$.proc_pidinfo(pids[0], 3, 0, pidInfo, 2000 );
let arr = []
for (let i = 0; i < 2000; i++) {
arr.push(String.fromCharCode(pidInfo[i]))
}
console.log(arr)The issue is that the fields are not going to be defined at all. Example output with |
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I realize this thread is a little old, but you may have better luck deciphering the output if you clear the allocated memory prior to passing it through the target function. Here's an example implementing the deprecated function run(argv) {
ObjC.bindFunction('malloc', ['void*', ['int']]); // bind malloc
ObjC.bindFunction('memset', ['void *', ['void *', 'int', 'int']]); // bind memset to clear allocated memory
const PID = 516; // query for PID 516 (Brave Browser on my system at the time of this demo)
const bytes = 8; // allocate 8 bytes -- for ProcessSerialNumber struct with two UInt32 fields
let psn = $.malloc(bytes); // allocate the memory
$.memset(psn, 0, bytes); // clear the memory
ObjC.bindFunction('GetProcessForPID', ['int', ['int', 'void *']]); // override bind GetProcessForPID to ignore JXA type safety
$.GetProcessForPID(PID, psn); // call the function
// assemble the output for review
let arr = [];
for (let i = 0; i < bytes; i++) {
arr.push(psn[i]);
}
return JSON.stringify(arr);
}In my own test, I got back: [0,0,0,0,15,240,0,0]This can be read as two |
I asked this question in stackoverflow as well:
I have a JXA function that binds the
libproc.dylibfunctionproc_pidinfoand then I attempt to call the function like so:However, the
pidinfoargument needs to be a pointer to theprocinfo.hstructproc_bsdinfo. I tried a few things like initializing a variable as a reference (var pidInfo = Ref();) with no type value, as well as several other type values (including "struct") as an argument, but nothing has worked:How do I initialize the
proc_bsdinfostruct?The text was updated successfully, but these errors were encountered: