Add additional API surfaces for searching procs

Sources/Swexy/Utilities/File.swift

@@ -7,6 +7,45 @@
 
 import Foundation
 
+private func _NSLookupProcessesAtPath(_ path: Int32...) -> [kinfo_proc] {
+    let pathCount = u_int(path.count)
+    var length: Int = 0
+
+    return path.withUnsafeBufferPointer { pathBuffer in
+        switch sysctl(UnsafeMutablePointer(mutating: pathBuffer.baseAddress!), pathCount, nil, &length, nil, 0) {
+        case 0:
+            let count = length / MemoryLayout<kinfo_proc>.stride
+            var result = [kinfo_proc](repeating: kinfo_proc(), count: count)
+            switch sysctl(UnsafeMutablePointer(mutating: pathBuffer.baseAddress!), pathCount, &result, &length, nil, 0) {
+            case 0:
+                return result
+            case let error:
+                break
+            }
+        case let error:
+            break
+        }
+
+        return []
+    }
+}
+
+public func NSLookupProcessesForUser(uid: uid_t) -> [kinfo_proc] {
+    _NSLookupProcessesAtPath(CTL_KERN, KERN_PROC, KERN_PROC_UID, Int32(uid))
+}
+
+public func NSLookupProcessesForUser(ruid: uid_t) -> [kinfo_proc] {
+    _NSLookupProcessesAtPath(CTL_KERN, KERN_PROC, KERN_PROC_RUID, Int32(ruid))
+}
+
+public func NSLookupProcessesForProcessGroup(pid: pid_t) -> [kinfo_proc] {
+    _NSLookupProcessesAtPath(CTL_KERN, KERN_PROC, KERN_PROC_PGRP, Int32(pid))
+}
+
+public func NSLookupAllProcesses() -> [kinfo_proc] {
+    _NSLookupProcessesAtPath(CTL_KERN, KERN_PROC, KERN_PROC_ALL, 0)
+}
+
 public func NSLookupProcessInfo(_ processIdentifier: pid_t) -> kinfo_proc? {
     var proc: kinfo_proc = kinfo_proc()
     var procSize = MemoryLayout<kinfo_proc>.size