libvirt/examples/c/misc/hellolibvirt.c

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/* This file contains trivial example code to connect to the running
* hypervisor and gather a few bits of information about domains.
* Similar API's exist for storage pools, networks, and interfaces. */
#include <stdio.h>
#include <stdlib.h>
#include <libvirt/libvirt.h>
#include <libvirt/virterror.h>
static int
showHypervisorInfo(virConnectPtr conn)
{
int ret = 0;
unsigned long hvVer, major, minor, release;
const char *hvType;
/* virConnectGetType returns a pointer to a static string, so no
* allocation or freeing is necessary; it is possible for the call
* to fail if, for example, there is no connection to a
* hypervisor, so check what it returns. */
hvType = virConnectGetType(conn);
if (!hvType) {
ret = 1;
printf("Failed to get hypervisor type: %s\n",
virGetLastErrorMessage());
goto out;
}
if (0 != virConnectGetVersion(conn, &hvVer)) {
ret = 1;
printf("Failed to get hypervisor version: %s\n",
virGetLastErrorMessage());
goto out;
}
major = hvVer / 1000000;
hvVer %= 1000000;
minor = hvVer / 1000;
release = hvVer % 1000;
printf("Hypervisor: \"%s\" version: %lu.%lu.%lu\n",
hvType,
major,
minor,
release);
out:
return ret;
}
static int
showDomains(virConnectPtr conn)
{
int ret = 0, numNames, numInactiveDomains, numActiveDomains;
ssize_t i;
int flags = VIR_CONNECT_LIST_DOMAINS_ACTIVE |
VIR_CONNECT_LIST_DOMAINS_INACTIVE;
virDomainPtr *nameList = NULL;
/* NB: The return from the virConnectNum*() APIs is only useful for
* the current call. A domain could be started or stopped and any
* assumptions made purely on these return values could result in
* unexpected results */
numActiveDomains = virConnectNumOfDomains(conn);
if (numActiveDomains == -1) {
ret = 1;
printf("Failed to get number of active domains: %s\n",
virGetLastErrorMessage());
goto out;
}
numInactiveDomains = virConnectNumOfDefinedDomains(conn);
if (numInactiveDomains == -1) {
ret = 1;
printf("Failed to get number of inactive domains: %s\n",
virGetLastErrorMessage());
goto out;
}
printf("There are %d active and %d inactive domains\n",
numActiveDomains, numInactiveDomains);
/* Return a list of all active and inactive domains. Using this API
* instead of virConnectListDomains() and virConnectListDefinedDomains()
* is preferred since it "solves" an inherit race between separated API
* calls if domains are started or stopped between calls */
numNames = virConnectListAllDomains(conn,
&nameList,
flags);
if (numNames == -1) {
ret = 1;
printf("Failed to get a list of all domains: %s\n",
virGetLastErrorMessage());
goto out;
}
for (i = 0; i < numNames; i++) {
int active = virDomainIsActive(nameList[i]);
printf(" %8s (%s)\n",
virDomainGetName(nameList[i]),
(active == 1 ? "active" : "non-active"));
/* must free the returned named per the API documentation */
virDomainFree(nameList[i]);
}
free(nameList);
out:
return ret;
}
int
main(int argc, char *argv[])
{
int ret = 0;
virConnectPtr conn;
char *uri;
printf("Attempting to connect to hypervisor\n");
uri = (argc > 0 ? argv[1] : NULL);
/* virConnectOpenAuth is called here with all default parameters,
* except, possibly, the URI of the hypervisor. */
conn = virConnectOpenAuth(uri, virConnectAuthPtrDefault, 0);
if (!conn) {
ret = 1;
printf("No connection to hypervisor: %s\n",
virGetLastErrorMessage());
goto out;
}
uri = virConnectGetURI(conn);
if (!uri) {
ret = 1;
printf("Failed to get URI for hypervisor connection: %s\n",
virGetLastErrorMessage());
goto disconnect;
}
printf("Connected to hypervisor at \"%s\"\n", uri);
free(uri);
if (0 != showHypervisorInfo(conn)) {
ret = 1;
goto disconnect;
}
if (0 != showDomains(conn)) {
ret = 1;
goto disconnect;
}
disconnect:
if (0 != virConnectClose(conn)) {
printf("Failed to disconnect from hypervisor: %s\n",
virGetLastErrorMessage());
ret = 1;
} else {
printf("Disconnected from hypervisor\n");
}
out:
return ret;
}