nsss
Software
skarnet.org

The nsssd library interface

General information

libnsssd is a library that can be used by external applications to implement extra nsss backends, in the style of nsssd-unix and nsssd-nslcd, without learning the details of the nsss protocol or having to perform IO themselves.

Compiling

• Make sure the nsss headers, as well as the skalibs headers, are visible in your header search path.
• Use #include <skalibs/strerr2.h> and #include <nsss/nsssd.h>

Linking

• Make sure the nsssd library, as well as the skalibs library, are visible in your library search path.
• Link against -lnsssd, -lskarnet,
`cat $SYSDEPS/socket.lib` and `cat $SYSDEPS/tainnow.lib`, $SYSDEPS being your skalibs sysdeps directory.

Programming

• In your main() function, start with assigning the name of your program to the PROG variable. Example: PROG = "nsssd-foobar";
• Your main() function can parse options and take command line arguments as it sees fit. But once it's done parsing options, give control to the nsssd_main() function, using your argv and envp as arguments: return nsssd_main(argv, envp);

The rest of your program should implement the functions needed by nsssd_main(). Here is what those functions are:

void *nsssd_handle_init (void)

This function must return a pointer to an uninitialized handle. The handle can be whatever you need to implement your backend; the pointer to your handle will be passed to every subsequent function. The function must not return NULL.

int nsssd_handle_start (void *handle, char const *const *argv, char const *const *envp)

This function must initialize the handle. The arguments it receives are the argv and envp that have been passed to nsssd_main(). This allows you to write daemons that can be somewhat configured via the command line: it is how nsssd-nslcd takes an argument telling it where the nslcd socket is, and uses that argument in its own nsssd_handle_start to actually connect to the nslcd daemon.
The function must return nonzero if it succeeds, and 0 if it fails, setting errno appropriately.

void nsssd_handle_end (void *handle)

This function must deinitialize the handle and free all related resources: close connections to external processes, etc.

TODO: to be completed.