qemu/migration-exec.c

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/*
* QEMU live migration
*
* Copyright IBM, Corp. 2008
* Copyright Dell MessageOne 2008
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
* Charles Duffy <charles_duffy@messageone.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
* Contributions after 2012-01-13 are licensed under the terms of the
* GNU GPL, version 2 or (at your option) any later version.
*/
#include "qemu-common.h"
#include "qemu_socket.h"
#include "migration.h"
#include "qemu-char.h"
#include "buffered_file.h"
#include "block.h"
#include <sys/types.h>
#include <sys/wait.h>
//#define DEBUG_MIGRATION_EXEC
#ifdef DEBUG_MIGRATION_EXEC
#define DPRINTF(fmt, ...) \
do { printf("migration-exec: " fmt, ## __VA_ARGS__); } while (0)
#else
#define DPRINTF(fmt, ...) \
do { } while (0)
#endif
static int file_errno(MigrationState *s)
{
return errno;
}
static int file_write(MigrationState *s, const void * buf, size_t size)
{
return write(s->fd, buf, size);
}
static int exec_close(MigrationState *s)
{
int ret = 0;
DPRINTF("exec_close\n");
if (s->opaque) {
ret = qemu_fclose(s->opaque);
s->opaque = NULL;
s->fd = -1;
if (ret >= 0 && !(WIFEXITED(ret) && WEXITSTATUS(ret) == 0)) {
/* close succeeded, but non-zero exit code: */
ret = -EIO; /* fake errno value */
}
}
return ret;
}
int exec_start_outgoing_migration(MigrationState *s, const char *command)
{
FILE *f;
f = popen(command, "w");
if (f == NULL) {
DPRINTF("Unable to popen exec target\n");
goto err_after_popen;
}
s->fd = fileno(f);
if (s->fd == -1) {
DPRINTF("Unable to retrieve file descriptor for popen'd handle\n");
goto err_after_open;
}
socket_set_nonblock(s->fd);
s->opaque = qemu_popen(f, "w");
s->close = exec_close;
s->get_error = file_errno;
s->write = file_write;
migrate_fd_connect(s);
return 0;
err_after_open:
pclose(f);
err_after_popen:
return -1;
}
static void exec_accept_incoming_migration(void *opaque)
{
QEMUFile *f = opaque;
process_incoming_migration(f);
qemu_set_fd_handler2(qemu_stdio_fd(f), NULL, NULL, NULL, NULL);
qemu_fclose(f);
}
int exec_start_incoming_migration(const char *command)
{
QEMUFile *f;
DPRINTF("Attempting to start an incoming migration\n");
f = qemu_popen_cmd(command, "r");
if(f == NULL) {
DPRINTF("Unable to apply qemu wrapper to popen file\n");
return -errno;
}
qemu_set_fd_handler2(qemu_stdio_fd(f), NULL,
exec_accept_incoming_migration, NULL, f);
return 0;
}