UPSCLI_INIT(3)
==============

NAME
----

upscli_init - Initialize upsclient module specifying security properties.

SYNOPSIS
--------

------
	#include <upsclient.h>

	int upscli_init(
		int certverify,
		const char *certpath,
		const char *certname,
		const char *certpasswd);
------

DESCRIPTION
-----------

The *upscli_init()* function initializes upsclient module and sets many
TLS/SSL-related properties: 'certverify' to 1 makes certificate verification
required for all SSL connections and 'certpath' is the location of
certificate database.

* If compiled with OpenSSL, 'certpath' refers to directory containing
  certificates where the certificates must be named according to their
  hash values ending in a ".0" extension. If two certificates result in
  the same hash value (thus file name), the ".0" can be incremented to ".1"
  and so on, as needed. The shell command for creating links in this manner
  would be:
+
----
:; ln -s ca.pem ./$(openssl x509 -hash -noout -in ca.pem).0
----
+
Alternatively, the `c_rehash` utility (provided by e.g. `openssl-perl`
  package) can take a directory and iterate it to link all certificates
  found in that directory, in the manner described above.

* If compiled with NSS, 'certpath' refers to a directory containing its
  database files.

If compiled with NSS and using SSL, you can specify 'certname' with the name
of the certificate to send to `upsd`, and 'certpasswd' with the password used
to decrypt certificate private key.

If compiled with NSS, it would normally log either the infamous message
"Init SSL without certificate database" if no 'certpath' was provided,
or "Init SSL with certificate database located at %s" otherwise.
Since some programmatic consumers become confused by such extra text on
the `stderr` of tools they call (such as monitoring systems doing `upsc`
queries), you can export an environment variable `NUT_QUIET_INIT_SSL`
with string values `"true"`, `"TRUE"` or `"1"`, to avoid logging these
messages and just emit them as debug stream (at verbosity 1 or higher).

As part of general initialization, *upscli_init()* function can call the
linkman:upscli_init_default_connect_timeout[3] method (if it was never used
before): this allows unmodified (legacy) NUT clients to consistently benefit
from presence of the `NUT_DEFAULT_CONNECT_TIMEOUT` environment variable for
linkman:upscli_connect[3] attempts to be not blocking (as per default).

You can call linkman:upscli_add_host_cert[3] to register specific host
security policy before initialize connections to them.

You must call linkman:upscli_cleanup[3] when exiting application.

Starting with NUT v2.8.5, you can use linkman:upscli_ssl_caps[3] from consumer
code to query the library about its build circumstances (whether it supports
SSL, and which backend(s)).

RETURN VALUE
------------

The *upscli_init()* function returns '1' on success, or '-1' if an error
occurs.

SEE ALSO
--------

linkman:upscli_add_host_cert[3], linkman:upscli_cleanup[3],
linkman:upscli_connect[3], linkman:upscli_disconnect[3],
linkman:upscli_init_default_connect_timeout[3], linkman:upscli_fd[3],
linkman:upscli_splitaddr[3], linkman:upscli_splitname[3],
linkman:upscli_ssl[3], linkman:upscli_ssl_caps[3],
linkman:upscli_ssl_caps_descr[3],
linkman:upscli_strerror[3], linkman:upscli_upserror[3]
