libvirt/examples/hellolibvirt/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. */
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <libvirt/libvirt.h>
#include <libvirt/virterror.h>
static void
showError(virConnectPtr conn)
{
int ret;
virErrorPtr err;
err = malloc(sizeof(*err));
if (NULL == err) {
printf("Could not allocate memory for error data\n");
goto out;
}
ret = virConnCopyLastError(conn, err);
switch (ret) {
case 0:
printf("No error found\n");
break;
case -1:
printf("Parameter error when attempting to get last error\n");
break;
default:
printf("libvirt reported: \"%s\"\n", err->message);
break;
}
virResetError(err);
free(err);
out:
return;
}
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 (NULL == hvType) {
ret = 1;
printf("Failed to get hypervisor type\n");
showError(conn);
goto out;
}
if (0 != virConnectGetVersion(conn, &hvVer)) {
ret = 1;
printf("Failed to get hypervisor version\n");
showError(conn);
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, i, numNames, numInactiveDomains, numActiveDomains;
char **nameList = NULL;
numActiveDomains = virConnectNumOfDomains(conn);
if (-1 == numActiveDomains) {
ret = 1;
printf("Failed to get number of active domains\n");
showError(conn);
goto out;
}
numInactiveDomains = virConnectNumOfDefinedDomains(conn);
if (-1 == numInactiveDomains) {
ret = 1;
printf("Failed to get number of inactive domains\n");
showError(conn);
goto out;
}
printf("There are %d active and %d inactive domains\n",
numActiveDomains, numInactiveDomains);
nameList = malloc(sizeof(*nameList) * numInactiveDomains);
if (NULL == nameList) {
ret = 1;
printf("Could not allocate memory for list of inactive domains\n");
goto out;
}
numNames = virConnectListDefinedDomains(conn,
nameList,
numInactiveDomains);
if (-1 == numNames) {
ret = 1;
printf("Could not get list of defined domains from hypervisor\n");
showError(conn);
goto out;
}
if (numNames > 0) {
printf("Inactive domains:\n");
}
for (i = 0 ; i < numNames ; i++) {
printf(" %s\n", *(nameList + i));
/* The API documentation doesn't say so, but the names
* returned by virConnectListDefinedDomains are strdup'd and
* must be freed here. */
free(*(nameList + i));
}
out:
free(nameList);
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 (NULL == conn) {
ret = 1;
printf("No connection to hypervisor\n");
showError(conn);
goto out;
}
uri = virConnectGetURI(conn);
if (NULL == uri) {
ret = 1;
printf("Failed to get URI for hypervisor connection\n");
showError(conn);
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\n");
showError(conn);
ret = 1;
} else {
printf("Disconnected from hypervisor\n");
}
out:
return ret;
}