Richard W.M. Jones wrote:
On Fri, Jan 23, 2009 at 02:51:02PM -0500, Dave Allan wrote:
The examples directory doesn't have a trivial example of how to connect to a hypervisor, make a few calls, and disconnect, so I put one together. I would appreciate any suggestions on anything that I've done wrong as well as suggestions for other fundamental API calls that should be illustrated.
Yes, I checked this example code and it is fine. My only comment would be on:
+ /* virConnectOpenAuth called here with all default parameters */ + conn = virConnectOpenAuth(NULL, virConnectAuthPtrDefault, 0);
It might be better to let people connect to a named URI.
Another possibility is to default to the test URI (test:///default) since that (almost) always exists.
Hi Rich, Thanks for taking a look at it. I added a little code to let the user specify a URI on the command line. Do you think it is worth committing? Dave diff --git a/examples/hellolibvirt/hellolibvirt.c b/examples/hellolibvirt/hellolibvirt.c new file mode 100644 index 0000000..22d3309 --- /dev/null +++ b/examples/hellolibvirt/hellolibvirt.c @@ -0,0 +1,151 @@ +/* This file contains trivial example code to connect to the running + * hypervisor and gather a few bits of information. */ + +#include <stdio.h> +#include <stdlib.h> +#include <libvirt/libvirt.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 (NULL == hvType) { + ret = 1; + printf("Failed to get hypervisor type\n"); + goto out; + } + + if (0 != virConnectGetVersion(conn, &hvVer)) { + ret = 1; + printf("Failed to get hypervisor version\n"); + 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); + numInactiveDomains = virConnectNumOfDefinedDomains(conn); + + printf("There are %d active and %d inactive domains\n", + numActiveDomains, numInactiveDomains); + + nameList = malloc(sizeof(char *) * (unsigned int)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"); + 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: + if (NULL != nameList) { + free(nameList); + } + + return ret; +} + + +int +main(int argc, char *argv[]) +{ + int ret = 0; + virConnectPtr conn = NULL; + char *uri = NULL; + + printf("Attempting to connect to hypervisor\n"); + + if (argc > 0) { + uri = argv[1]; + } + + /* 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"); + goto out; + } + + uri = virConnectGetURI(conn); + if (NULL == uri) { + ret = 1; + printf("Failed to get URI for hypervisor connection\n"); + 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"); + } else { + printf("Disconnected from hypervisor\n"); + } + +out: + return ret; +} commit c8f073fd4ff032b88dff78d0aae93576a8dcf035 Author: David Allan <dallan@redhat.com> Date: Mon Jan 26 23:37:21 2009 -0500 Added a little code to let the user specify the URI of the hypervisor on the command line, per the suggestion of Rich Jones. diff --git a/examples/hellolibvirt/hellolibvirt.c b/examples/hellolibvirt/hellolibvirt.c index aae79b8..22d3309 100644 --- a/examples/hellolibvirt/hellolibvirt.c +++ b/examples/hellolibvirt/hellolibvirt.c @@ -97,15 +97,21 @@ out: int -main(void) +main(int argc, char *argv[]) { int ret = 0; virConnectPtr conn = NULL; + char *uri = NULL; printf("Attempting to connect to hypervisor\n"); - /* virConnectOpenAuth called here with all default parameters */ - conn = virConnectOpenAuth(NULL, virConnectAuthPtrDefault, 0); + if (argc > 0) { + uri = argv[1]; + } + + /* 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; @@ -113,7 +119,15 @@ main(void) goto out; } - printf("Connected to hypervisor\n"); + uri = virConnectGetURI(conn); + if (NULL == uri) { + ret = 1; + printf("Failed to get URI for hypervisor connection\n"); + goto disconnect; + } + + printf("Connected to hypervisor at \"%s\"\n", uri); + free(uri); if (0 != showHypervisorInfo(conn)) { ret = 1;