Currently, the filesystem and persistent storage areas are left undone, to be implemented by the application.
The SNMP library package is intended to support client and agent code alike. It therefore contains lots of assumptions about the presence of persistent storage ie. a filesystem. Currently, by default, eCos has no such thing, so those areas have been simply commented out and made to return empty lists or say “no data here.”
Specifically the following files have omitted/unimplemented code :
PACKAGES/net/snmp/lib/VERSION/src/parse.c
contains code to enumerate MIB files discovered in the system MIB directories (“/usr/share/snmp/mibs”), and read them all in, building data structures that are used by client programs to interrogate an agent. This is not required in an agent, so the routine which enumerates the directories returns an empty list.
PACKAGES/net/snmp/lib/VERSION/src/read_config.c contains two systems:
The first tries to read the configuration file as described in the snmpd.conf file section and the second system contains code to record persistent data as files in a directory (typically /var/ucd-snmp) thus preserving the state permanently.
The first part is partially implemented to support multiple profiles and enables dispatcher functionality as discussed in the Section called Version usage (v1, v2 or v3). The second part is not supported at all in the default implementation. As required, a cleaner interface to permit application code to manage persistent data will be developed in consultation with customers.