make function to determine parent process, since that process should contain all juicy threads

include/process.h

@@ -35,6 +35,12 @@ int process_parse_status(pid_t pid, process_status_t* status);
 // find any process that matches name, case insensitive.
 // list pointer must point to NULL-initialized pointer, and count pointer must pount to initialized 0
 // will skip any process which status couldn't be parsed 
+// deallocate list with free later
 int processes_by_name(const char* name, process_status_t** list, size_t* count);
 
+// will determine parent process amongst children and set parent pointer to element in list
+// process list must consist of parent and children processes,
+// obtained from processes_by_name call. of course parent pointer shouldn't be NULL
+int determine_parent_process(process_status_t* list, size_t count, process_status_t** parent);
+
 #endif

src/main.c

@@ -24,8 +24,15 @@ int main(int argc, char** argv)
     size_t count = 0;
 
     processes_by_name("dummy_target", &list, &count);
-    for (size_t i = 0; i < count; i++)
-        print_process(&list[i]);
+    process_status_t* parent;
+    if (determine_parent_process(list, count, &parent))
+    {
+        fputs("unable to determine parent process. exiting", stderr);
+        free(list);
+        return 1;
+    }
+
+    print_process(parent);
     
     free(list);
     return 0;

src/process.c

@@ -111,4 +111,29 @@ int processes_by_name(const char* name, process_status_t** list, size_t* count)
 
     closedir(proc);
     return 0;
+}
+
+static process_status_t* process_by_pid_in_list(pid_t pid, process_status_t* list, size_t count)
+{
+    for (size_t i = 0; i < count; i++)
+        if (list[i].pid == pid) return &list[i];
+    
+    return NULL;
+}
+
+int determine_parent_process(process_status_t* list, size_t count, process_status_t** parent)
+{
+    // we're gonna find any process that doesnt have parent in this list,
+    // that means we hit real parent, not descendant
+    for (size_t i = 0; i < count; i++)
+    {
+        if (!process_by_pid_in_list(list[i].ppid, list, count))
+        {
+            // that's real parent
+            *parent = &list[i];
+            return 0;
+        }
+    }
+
+    return 1;
 }