[SSSD] GDB pretty printers

Hi, I've been using the attached GDB helper script when debugging and I figured it might be useful for the others, too. I sometimes need to print and examine the contents of struct sysdb_attrs, ldb_message or similar. Using just the print command is quite tedious. The pretty printers can recursively print the contents of several commonly used structures. For example this is how the first several attributes of the IPA admin user look like: (gdb) p *attrs $1 = { <struct sysdb_attrs> num = 14 { <struct ldb_message_element> flags = 0, name = 0x85ba30 "originalDN", num_values = 1 { <struct ldb_val> data = 0x85dca0 "uid=admin,cn=users,cn=accounts,dc=idm,dc=lab,dc=bos,dc=redhat,dc=com", length = 68 } } { <struct ldb_message_element> flags = 0, name = 0x85b060 "name", num_values = 1 { <struct ldb_val> data = 0x85b130 "admin", length = 5 } } { <struct ldb_message_element> flags = 0, name = 0x85afc0 "uidNumber", num_values = 1 The other part is a new gdb command "tbr" which sets a breakpoint to the callback of a tevent_req without having to examine the contents of the tevent_req structure. For example: Breakpoint 1, sdap_get_users_process (subreq=0x85bf50) at src/providers/ldap/sdap_async_users.c:483 483 { (gdb) n 484 struct tevent_req *req = tevent_req_callback_data(subreq, (gdb) 486 struct sdap_get_users_state *state = tevent_req_data(req, (gdb) tbr req Breakpoint 2 at 0x7fe6c211b9c1: file src/providers/ldap/ldap_id.c, line 185. (gdb) c Continuing. Breakpoint 2, users_get_done (subreq=0x900004000) at src/providers/ldap/ldap_id.c:185 185 { (gdb) The script can be loaded into gdb with the "source" command: (gdb) source /path/to/the/script.py