examples/misc/hellolibvirt.c

   1 /* This file contains trivial example code to connect to the running
   2  * hypervisor and gather a few bits of information about domains.
   3  * Similar API's exist for storage pools, networks, and interfaces. */
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <libvirt/libvirt.h>
   8 #include <libvirt/virterror.h>
   9
  10 static int
  11 showHypervisorInfo(virConnectPtr conn)
  12 {
  13     int ret = 0;
  14     unsigned long hvVer, major, minor, release;
  15     const char *hvType;
  16
  17     /* virConnectGetType returns a pointer to a static string, so no
  18      * allocation or freeing is necessary; it is possible for the call
  19      * to fail if, for example, there is no connection to a
  20      * hypervisor, so check what it returns. */
  21     hvType = virConnectGetType(conn);
  22     if (!hvType) {
  23         ret = 1;
  24         printf("Failed to get hypervisor type: %s\n",
  25                virGetLastErrorMessage());
  26         goto out;
  27     }
  28
  29     if (0 != virConnectGetVersion(conn, &hvVer)) {
  30         ret = 1;
  31         printf("Failed to get hypervisor version: %s\n",
  32                virGetLastErrorMessage());
  33         goto out;
  34     }
  35
  36     major = hvVer / 1000000;
  37     hvVer %= 1000000;
  38     minor = hvVer / 1000;
  39     release = hvVer % 1000;
  40
  41     printf("Hypervisor: \"%s\" version: %lu.%lu.%lu\n",
  42            hvType,
  43            major,
  44            minor,
  45            release);
  46
  47  out:
  48     return ret;
  49 }
  50
  51
  52 static int
  53 showDomains(virConnectPtr conn)
  54 {
  55     int ret = 0, numNames, numInactiveDomains, numActiveDomains;
  56     ssize_t i;
  57     int flags = VIR_CONNECT_LIST_DOMAINS_ACTIVE |
  58                 VIR_CONNECT_LIST_DOMAINS_INACTIVE;
  59     virDomainPtr *nameList = NULL;
  60
  61     /* NB: The return from the virConnectNum*() APIs is only useful for
  62      * the current call.  A domain could be started or stopped and any
  63      * assumptions made purely on these return values could result in
  64      * unexpected results */
  65     numActiveDomains = virConnectNumOfDomains(conn);
  66     if (numActiveDomains == -1) {
  67         ret = 1;
  68         printf("Failed to get number of active domains: %s\n",
  69                virGetLastErrorMessage());
  70         goto out;
  71     }
  72
  73     numInactiveDomains = virConnectNumOfDefinedDomains(conn);
  74     if (numInactiveDomains == -1) {
  75         ret = 1;
  76         printf("Failed to get number of inactive domains: %s\n",
  77                virGetLastErrorMessage());
  78         goto out;
  79     }
  80
  81     printf("There are %d active and %d inactive domains\n",
  82            numActiveDomains, numInactiveDomains);
  83
  84     /* Return a list of all active and inactive domains. Using this API
  85      * instead of virConnectListDomains() and virConnectListDefinedDomains()
  86      * is preferred since it "solves" an inherit race between separated API
  87      * calls if domains are started or stopped between calls */
  88     numNames = virConnectListAllDomains(conn,
  89                                         &nameList,
  90                                         flags);
  91     if (numNames == -1) {
  92         ret = 1;
  93         printf("Failed to get a list of all domains: %s\n",
  94                virGetLastErrorMessage());
  95         goto out;
  96     }
  97
  98     for (i = 0; i < numNames; i++) {
  99         int active = virDomainIsActive(nameList[i]);
 100         printf("  %8s (%s)\n",
 101                virDomainGetName(nameList[i]),
 102                (active == 1 ? "active" : "non-active"));
 103         /* must free the returned named per the API documentation */
 104         virDomainFree(nameList[i]);
 105     }
 106     free(nameList);
 107
 108  out:
 109     return ret;
 110 }
 111
 112
 113 int
 114 main(int argc, char *argv[])
 115 {
 116     int ret = 0;
 117     virConnectPtr conn;
 118     char *uri;
 119
 120     printf("Attempting to connect to hypervisor\n");
 121
 122     uri = (argc > 0 ? argv[1] : NULL);
 123
 124     /* virConnectOpenAuth is called here with all default parameters,
 125      * except, possibly, the URI of the hypervisor. */
 126     conn = virConnectOpenAuth(uri, virConnectAuthPtrDefault, 0);
 127
 128     if (!conn) {
 129         ret = 1;
 130         printf("No connection to hypervisor: %s\n",
 131                virGetLastErrorMessage());
 132         goto out;
 133     }
 134
 135     uri = virConnectGetURI(conn);
 136     if (!uri) {
 137         ret = 1;
 138         printf("Failed to get URI for hypervisor connection: %s\n",
 139                virGetLastErrorMessage());
 140         goto disconnect;
 141     }
 142
 143     printf("Connected to hypervisor at \"%s\"\n", uri);
 144     free(uri);
 145
 146     if (0 != showHypervisorInfo(conn)) {
 147         ret = 1;
 148         goto disconnect;
 149     }
 150
 151     if (0 != showDomains(conn)) {
 152         ret = 1;
 153         goto disconnect;
 154     }
 155
 156  disconnect:
 157     if (0 != virConnectClose(conn)) {
 158         printf("Failed to disconnect from hypervisor: %s\n",
 159                virGetLastErrorMessage());
 160         ret = 1;
 161     } else {
 162         printf("Disconnected from hypervisor\n");
 163     }
 164
 165  out:
 166     return ret;
 167 }