Here we hope to put a few tests for you to see if you are fit in C to fiddle around with the gtk-gnutella code. They are taken from our experiences with the pitfalls of coding on the project.
Author: Richard Eckart
Difficulty: moderate
The code below extracts the user agent from the headers of an upload. The
gui displays the useragent string or "..." if u->user_agent is
NULL.
Unfortunately there is a bug in that piece of code that caused the GUI of
our test user to always display "...". Can you locate it?
1: /*
2: * Extract User-Agent.
3: *
4: * X-Token: GTKG token
5: * User-Agent: whatever
6: * Server: whatever (in case no User-Agent)
7: */
8:
9: token = header_get(header, "X-Token");
10: user_agent = header_get(header, "User-Agent");
11:
12: /* Maybe they sent a Server: line, thinking they're a server? */
13: if (user_agent != NULL)
14: user_agent = header_get(header, "Server");
15:
16: if (user_agent != NULL)
17: faked = !version_check(user_agent, token, u->ip);
18:
19: if (u->user_agent == NULL && user_agent != NULL) {
20: if (faked) {
21: gchar *name = g_strdup_printf("!%s", user_agent);
22:
23: u->user_agent = atom_str_get(name);
24: g_free(name);
25: } else
26: u->user_agent = atom_str_get(user_agent);
27: }
Author: Richard Eckart
Difficulty: moderate
While running gtkg compiled with Gtk1 support we found that the code below contains a memory leak. There are two places in the code where new memory is allocated. Those are on the lines 18 and 19. Can you find out where the leak is?
1: /*
2: * on_popup_downloads_push_activate
3: *
4: * All selected downloads fallback to push
5: */
6: void on_popup_downloads_push_activate(
7: GtkMenuItem * menuitem, gpointer user_data)
8: {
9: struct download *d;
10: GList *node_list, *data_list = NULL;
11: GtkCTree *ctree_downloads = GTK_CTREE
12: (lookup_widget(main_window, "ctree_downloads"));
13: GtkCTree *ctree_downloads_queue = GTK_CTREE
14: (lookup_widget(main_window, "ctree_downloads_queue"));
15:
16: gtk_clist_freeze(GTK_CLIST(ctree_downloads_queue));
17: gtk_clist_freeze(GTK_CLIST(ctree_downloads));
18: node_list = g_list_copy(GTK_CLIST(ctree_downloads)->selection);
19: data_list = downloads_gui_collect_ctree_data(ctree_downloads,
20: node_list, TRUE, TRUE);
21:
23: for (; NULL != data_list; data_list = g_list_next(data_list)) {
24: d = (struct download *) data_list->data;
25:
26: if (!d) {
27: g_warning(
28: "on_popup_downloads_push_activate(): row has NULL data\n");
29: continue;
30: }
31: download_fallback_to_push(d, FALSE, TRUE);
32: }
33:
34: gtk_clist_thaw(GTK_CLIST(ctree_downloads_queue));
35: gtk_clist_thaw(GTK_CLIST(ctree_downloads));
36: g_list_free(data_list);
37: g_list_free(node_list);
38: }
The answers are here on a separate page. Don't cheat yourself by reading a answer before trying the test.