libvirt/docs/examples/suspend.c

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/**
* section: Scheduling
* synopsis: Suspend a domain and then resume its execution
* purpose: Demonstrate the basic use of the library to suspend and
* resume a domain. If no id is given on the command line
* this script will suspend and resume the first domain found
* which is not Domain 0.
* usage: suspend [id]
* test: suspend
* author: Daniel Veillard
* copy: see Copyright for the status of this software.
*/
#include <stdlib.h>
#include <stdio.h>
#include <libvirt/libvirt.h>
static virConnectPtr conn = NULL; /* the hypervisor connection */
/**
* checkDomainState:
* @dom: the domain
*
* Return the current state of a domain or -1 if non-exsitant
*/
static int
checkDomainState(virDomainPtr dom) {
virDomainInfo info; /* the information being fetched */
int ret;
ret = virDomainGetInfo(dom, &info);
if (ret < 0) {
return(-1);
}
return(info.state);
}
/**
* SuspendAndResumeDomain:
* @id: the id of the domain
*
* extract the domain 0 information
*/
static void
SuspendAndResumeDomain(int id) {
virDomainPtr dom = NULL; /* the domain being checked */
int ret, state;
/* Find the domain of the given id */
dom = virDomainLookupByID(conn, id);
if (dom == NULL) {
fprintf(stderr, "Failed to find Domain %d\n", id);
goto error;
}
/* Check state */
state = checkDomainState(dom);
if ((state == VIR_DOMAIN_RUNNING) ||
(state == VIR_DOMAIN_NOSTATE) ||
(state == VIR_DOMAIN_BLOCKED)) {
printf("Suspending domain...\n");
ret = virDomainSuspend(dom);
if (ret < 0) {
fprintf(stderr, "Failed to suspend Domain %d\n", id);
goto error;
}
state = checkDomainState(dom);
if (state != VIR_DOMAIN_PAUSED) {
fprintf(stderr, "Domain %d state is not suspended\n", id);
} else {
printf("Domain suspended, resuming it...\n");
}
ret = virDomainResume(dom);
if (ret < 0) {
fprintf(stderr, "Failed to resume Domain %d\n", id);
goto error;
}
state = checkDomainState(dom);
if ((state == VIR_DOMAIN_RUNNING) ||
(state == VIR_DOMAIN_NOSTATE) ||
(state == VIR_DOMAIN_BLOCKED)) {
printf("Domain resumed\n");
} else {
fprintf(stderr, "Domain %d state indicate it is not resumed\n", id);
}
} else {
fprintf(stderr, "Domain %d is not in a state where it should be suspended\n", id);
goto error;
}
error:
if (dom != NULL)
virDomainFree(dom);
}
int main(int argc, char **argv) {
int id = 0;
/* NULL means connect to local Xen hypervisor */
conn = virConnectOpenReadOnly(NULL);
if (conn == NULL) {
fprintf(stderr, "Failed to connect to hypervisor\n");
goto error;
}
if (argc > 1) {
id = atoi(argv[1]);
}
if (id == 0) {
int i, j, ids[10];
i = virConnectListDomains(conn, &ids[0], 10);
if (i < 0) {
fprintf(stderr, "Failed to list the domains\n");
goto error;
}
for (j = 0;j < i;j++) {
if (ids[j] != 0) {
id = ids[j];
break;
}
}
}
if (id == 0) {
fprintf(stderr, "Failed find a running guest domain\n");
goto error;
}
SuspendAndResumeDomain(id);
error:
if (conn != NULL)
virConnectClose(conn);
return(0);
}