InfoScale™ 9.0 Cluster Server Agent Developer's Guide - AIX, Linux, Solaris, Windows

VCSAgSetCookie2

void *VCSAgSetCookie2(const char *name, void *cookie)

This primitive requests the agent framework to store a cookie given by the void *cookie parameter. If there is a value already associated with the cookie, the primitive sets the new value and atomically returns the old value. If there is no value associated with the cookie then it sets a new value in the cookie and returns NULL.

This value, which is transparent to the agent framework, can be obtained by calling the primitive VCSAgGetCookie(). A cookie is not stored permanently. It is lost when the agent process exits. This primitive can be called from any entry point. For example:

#include "VCSAgApi.h"
...
// Assume that the online, offline, and monitor
// operations on resource require a certain key. Also
// assume that obtaining this key is time consuming, but
// that it can be reused until this process is
// terminated.
//
// In this example, the open entry point obtains the key
// and stores it as a cookie. Subsequent online,
// offline, and monitor entry points get the cookie and
// use the key.
//
// Note that the cookie name can be any unique string.
// This example uses the resource name as the cookie
// name.
//
void *get_key() {
               ...
}
void res_open(const char *res_name, void **attr_val) {
              if (VCSAgGetCookie(res_name) == NULL) {
                         void *key = get_key();
                         VCSAgSetCookie2(res_name, key);
              }
}
VCSAgResState res_monitor(const char *res_name, void
              **attr_val, int *conf_level_ptr) {
              VCSAgResState state = VCSAgResUnknown;
              *conf_level_ptr = 0;
              void *key = VCSAgGetCookie(res_name);
              if (key == NULL) {
                  // Take care of the rare cases when
                  // the open entry point failed to
                  //  obtain the key and set the the cookie.
                         key = get_key();
                         VCSAgSetCookie2(res_name, key);
              }
              // Use the key for testing if the resource is
              // online, and set the state accordingly.
              ...
              return state;
}