qemu/qga/guest-agent-commands.c

562 lines
14 KiB
C

/*
* QEMU Guest Agent commands
*
* Copyright IBM Corp. 2011
*
* Authors:
* Michael Roth <mdroth@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include <glib.h>
#if defined(__linux__)
#include <mntent.h>
#include <linux/fs.h>
#if defined(__linux__) && defined(FIFREEZE)
#define CONFIG_FSFREEZE
#endif
#endif
#include <sys/types.h>
#include <sys/ioctl.h>
#include "qga/guest-agent-core.h"
#include "qga-qmp-commands.h"
#include "qerror.h"
#include "qemu-queue.h"
static GAState *ga_state;
/* Note: in some situations, like with the fsfreeze, logging may be
* temporarilly disabled. if it is necessary that a command be able
* to log for accounting purposes, check ga_logging_enabled() beforehand,
* and use the QERR_QGA_LOGGING_DISABLED to generate an error
*/
static void slog(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
g_logv("syslog", G_LOG_LEVEL_INFO, fmt, ap);
va_end(ap);
}
int64_t qmp_guest_sync(int64_t id, Error **errp)
{
return id;
}
void qmp_guest_ping(Error **err)
{
slog("guest-ping called");
}
struct GuestAgentInfo *qmp_guest_info(Error **err)
{
GuestAgentInfo *info = qemu_mallocz(sizeof(GuestAgentInfo));
info->version = g_strdup(QGA_VERSION);
return info;
}
void qmp_guest_shutdown(bool has_mode, const char *mode, Error **err)
{
int ret;
const char *shutdown_flag;
slog("guest-shutdown called, mode: %s", mode);
if (!has_mode || strcmp(mode, "powerdown") == 0) {
shutdown_flag = "-P";
} else if (strcmp(mode, "halt") == 0) {
shutdown_flag = "-H";
} else if (strcmp(mode, "reboot") == 0) {
shutdown_flag = "-r";
} else {
error_set(err, QERR_INVALID_PARAMETER_VALUE, "mode",
"halt|powerdown|reboot");
return;
}
ret = fork();
if (ret == 0) {
/* child, start the shutdown */
setsid();
fclose(stdin);
fclose(stdout);
fclose(stderr);
ret = execl("/sbin/shutdown", "shutdown", shutdown_flag, "+0",
"hypervisor initiated shutdown", (char*)NULL);
if (ret) {
slog("guest-shutdown failed: %s", strerror(errno));
}
exit(!!ret);
} else if (ret < 0) {
error_set(err, QERR_UNDEFINED_ERROR);
}
}
typedef struct GuestFileHandle {
uint64_t id;
FILE *fh;
QTAILQ_ENTRY(GuestFileHandle) next;
} GuestFileHandle;
static struct {
QTAILQ_HEAD(, GuestFileHandle) filehandles;
} guest_file_state;
static void guest_file_handle_add(FILE *fh)
{
GuestFileHandle *gfh;
gfh = qemu_mallocz(sizeof(GuestFileHandle));
gfh->id = fileno(fh);
gfh->fh = fh;
QTAILQ_INSERT_TAIL(&guest_file_state.filehandles, gfh, next);
}
static GuestFileHandle *guest_file_handle_find(int64_t id)
{
GuestFileHandle *gfh;
QTAILQ_FOREACH(gfh, &guest_file_state.filehandles, next)
{
if (gfh->id == id) {
return gfh;
}
}
return NULL;
}
int64_t qmp_guest_file_open(const char *path, bool has_mode, const char *mode, Error **err)
{
FILE *fh;
int fd;
int64_t ret = -1;
if (!has_mode) {
mode = "r";
}
slog("guest-file-open called, filepath: %s, mode: %s", path, mode);
fh = fopen(path, mode);
if (!fh) {
error_set(err, QERR_OPEN_FILE_FAILED, path);
return -1;
}
/* set fd non-blocking to avoid common use cases (like reading from a
* named pipe) from hanging the agent
*/
fd = fileno(fh);
ret = fcntl(fd, F_GETFL);
ret = fcntl(fd, F_SETFL, ret | O_NONBLOCK);
if (ret == -1) {
error_set(err, QERR_QGA_COMMAND_FAILED, "fcntl() failed");
fclose(fh);
return -1;
}
guest_file_handle_add(fh);
slog("guest-file-open, handle: %d", fd);
return fd;
}
void qmp_guest_file_close(int64_t handle, Error **err)
{
GuestFileHandle *gfh = guest_file_handle_find(handle);
int ret;
slog("guest-file-close called, handle: %ld", handle);
if (!gfh) {
error_set(err, QERR_FD_NOT_FOUND, "handle");
return;
}
ret = fclose(gfh->fh);
if (ret == -1) {
error_set(err, QERR_QGA_COMMAND_FAILED, "fclose() failed");
return;
}
QTAILQ_REMOVE(&guest_file_state.filehandles, gfh, next);
qemu_free(gfh);
}
struct GuestFileRead *qmp_guest_file_read(int64_t handle, bool has_count,
int64_t count, Error **err)
{
GuestFileHandle *gfh = guest_file_handle_find(handle);
GuestFileRead *read_data = NULL;
guchar *buf;
FILE *fh;
size_t read_count;
if (!gfh) {
error_set(err, QERR_FD_NOT_FOUND, "handle");
return NULL;
}
if (!has_count) {
count = QGA_READ_COUNT_DEFAULT;
} else if (count < 0) {
error_set(err, QERR_INVALID_PARAMETER, "count");
return NULL;
}
fh = gfh->fh;
buf = qemu_mallocz(count+1);
read_count = fread(buf, 1, count, fh);
if (ferror(fh)) {
slog("guest-file-read failed, handle: %ld", handle);
error_set(err, QERR_QGA_COMMAND_FAILED, "fread() failed");
} else {
buf[read_count] = 0;
read_data = qemu_mallocz(sizeof(GuestFileRead));
read_data->count = read_count;
read_data->eof = feof(fh);
if (read_count) {
read_data->buf_b64 = g_base64_encode(buf, read_count);
}
}
qemu_free(buf);
clearerr(fh);
return read_data;
}
GuestFileWrite *qmp_guest_file_write(int64_t handle, const char *buf_b64,
bool has_count, int64_t count, Error **err)
{
GuestFileWrite *write_data = NULL;
guchar *buf;
gsize buf_len;
int write_count;
GuestFileHandle *gfh = guest_file_handle_find(handle);
FILE *fh;
if (!gfh) {
error_set(err, QERR_FD_NOT_FOUND, "handle");
return NULL;
}
fh = gfh->fh;
buf = g_base64_decode(buf_b64, &buf_len);
if (!has_count) {
count = buf_len;
} else if (count < 0 || count > buf_len) {
qemu_free(buf);
error_set(err, QERR_INVALID_PARAMETER, "count");
return NULL;
}
write_count = fwrite(buf, 1, count, fh);
if (ferror(fh)) {
slog("guest-file-write failed, handle: %ld", handle);
error_set(err, QERR_QGA_COMMAND_FAILED, "fwrite() error");
} else {
write_data = qemu_mallocz(sizeof(GuestFileWrite));
write_data->count = write_count;
write_data->eof = feof(fh);
}
qemu_free(buf);
clearerr(fh);
return write_data;
}
struct GuestFileSeek *qmp_guest_file_seek(int64_t handle, int64_t offset,
int64_t whence, Error **err)
{
GuestFileHandle *gfh = guest_file_handle_find(handle);
GuestFileSeek *seek_data = NULL;
FILE *fh;
int ret;
if (!gfh) {
error_set(err, QERR_FD_NOT_FOUND, "handle");
return NULL;
}
fh = gfh->fh;
ret = fseek(fh, offset, whence);
if (ret == -1) {
error_set(err, QERR_QGA_COMMAND_FAILED, strerror(errno));
} else {
seek_data = qemu_mallocz(sizeof(GuestFileRead));
seek_data->position = ftell(fh);
seek_data->eof = feof(fh);
}
clearerr(fh);
return seek_data;
}
void qmp_guest_file_flush(int64_t handle, Error **err)
{
GuestFileHandle *gfh = guest_file_handle_find(handle);
FILE *fh;
int ret;
if (!gfh) {
error_set(err, QERR_FD_NOT_FOUND, "handle");
return;
}
fh = gfh->fh;
ret = fflush(fh);
if (ret == EOF) {
error_set(err, QERR_QGA_COMMAND_FAILED, strerror(errno));
}
}
static void guest_file_init(void)
{
QTAILQ_INIT(&guest_file_state.filehandles);
}
#if defined(CONFIG_FSFREEZE)
static void disable_logging(void)
{
ga_disable_logging(ga_state);
}
static void enable_logging(void)
{
ga_enable_logging(ga_state);
}
typedef struct GuestFsfreezeMount {
char *dirname;
char *devtype;
QTAILQ_ENTRY(GuestFsfreezeMount) next;
} GuestFsfreezeMount;
struct {
GuestFsfreezeStatus status;
QTAILQ_HEAD(, GuestFsfreezeMount) mount_list;
} guest_fsfreeze_state;
/*
* Walk the mount table and build a list of local file systems
*/
static int guest_fsfreeze_build_mount_list(void)
{
struct mntent *ment;
GuestFsfreezeMount *mount, *temp;
char const *mtab = MOUNTED;
FILE *fp;
QTAILQ_FOREACH_SAFE(mount, &guest_fsfreeze_state.mount_list, next, temp) {
QTAILQ_REMOVE(&guest_fsfreeze_state.mount_list, mount, next);
qemu_free(mount->dirname);
qemu_free(mount->devtype);
qemu_free(mount);
}
fp = setmntent(mtab, "r");
if (!fp) {
g_warning("fsfreeze: unable to read mtab");
return -1;
}
while ((ment = getmntent(fp))) {
/*
* An entry which device name doesn't start with a '/' is
* either a dummy file system or a network file system.
* Add special handling for smbfs and cifs as is done by
* coreutils as well.
*/
if ((ment->mnt_fsname[0] != '/') ||
(strcmp(ment->mnt_type, "smbfs") == 0) ||
(strcmp(ment->mnt_type, "cifs") == 0)) {
continue;
}
mount = qemu_mallocz(sizeof(GuestFsfreezeMount));
mount->dirname = qemu_strdup(ment->mnt_dir);
mount->devtype = qemu_strdup(ment->mnt_type);
QTAILQ_INSERT_TAIL(&guest_fsfreeze_state.mount_list, mount, next);
}
endmntent(fp);
return 0;
}
/*
* Return status of freeze/thaw
*/
GuestFsfreezeStatus qmp_guest_fsfreeze_status(Error **err)
{
return guest_fsfreeze_state.status;
}
/*
* Walk list of mounted file systems in the guest, and freeze the ones which
* are real local file systems.
*/
int64_t qmp_guest_fsfreeze_freeze(Error **err)
{
int ret = 0, i = 0;
struct GuestFsfreezeMount *mount, *temp;
int fd;
char err_msg[512];
slog("guest-fsfreeze called");
if (guest_fsfreeze_state.status == GUEST_FSFREEZE_STATUS_FROZEN) {
return 0;
}
ret = guest_fsfreeze_build_mount_list();
if (ret < 0) {
return ret;
}
/* cannot risk guest agent blocking itself on a write in this state */
disable_logging();
QTAILQ_FOREACH_SAFE(mount, &guest_fsfreeze_state.mount_list, next, temp) {
fd = qemu_open(mount->dirname, O_RDONLY);
if (fd == -1) {
sprintf(err_msg, "failed to open %s, %s", mount->dirname, strerror(errno));
error_set(err, QERR_QGA_COMMAND_FAILED, err_msg);
goto error;
}
/* we try to cull filesytems we know won't work in advance, but other
* filesytems may not implement fsfreeze for less obvious reasons.
* these will report EOPNOTSUPP, so we simply ignore them. when
* thawing, these filesystems will return an EINVAL instead, due to
* not being in a frozen state. Other filesystem-specific
* errors may result in EINVAL, however, so the user should check the
* number * of filesystems returned here against those returned by the
* thaw operation to determine whether everything completed
* successfully
*/
ret = ioctl(fd, FIFREEZE);
if (ret < 0 && errno != EOPNOTSUPP) {
sprintf(err_msg, "failed to freeze %s, %s", mount->dirname, strerror(errno));
error_set(err, QERR_QGA_COMMAND_FAILED, err_msg);
close(fd);
goto error;
}
close(fd);
i++;
}
guest_fsfreeze_state.status = GUEST_FSFREEZE_STATUS_FROZEN;
return i;
error:
if (i > 0) {
qmp_guest_fsfreeze_thaw(NULL);
}
return 0;
}
/*
* Walk list of frozen file systems in the guest, and thaw them.
*/
int64_t qmp_guest_fsfreeze_thaw(Error **err)
{
int ret;
GuestFsfreezeMount *mount, *temp;
int fd, i = 0;
bool has_error = false;
QTAILQ_FOREACH_SAFE(mount, &guest_fsfreeze_state.mount_list, next, temp) {
fd = qemu_open(mount->dirname, O_RDONLY);
if (fd == -1) {
has_error = true;
continue;
}
ret = ioctl(fd, FITHAW);
if (ret < 0 && errno != EOPNOTSUPP && errno != EINVAL) {
has_error = true;
close(fd);
continue;
}
close(fd);
i++;
}
if (has_error) {
guest_fsfreeze_state.status = GUEST_FSFREEZE_STATUS_ERROR;
} else {
guest_fsfreeze_state.status = GUEST_FSFREEZE_STATUS_THAWED;
}
enable_logging();
return i;
}
static void guest_fsfreeze_init(void)
{
guest_fsfreeze_state.status = GUEST_FSFREEZE_STATUS_THAWED;
QTAILQ_INIT(&guest_fsfreeze_state.mount_list);
}
static void guest_fsfreeze_cleanup(void)
{
int64_t ret;
Error *err = NULL;
if (guest_fsfreeze_state.status == GUEST_FSFREEZE_STATUS_FROZEN) {
ret = qmp_guest_fsfreeze_thaw(&err);
if (ret < 0 || err) {
slog("failed to clean up frozen filesystems");
}
}
}
#else
/*
* Return status of freeze/thaw
*/
GuestFsfreezeStatus qmp_guest_fsfreeze_status(Error **err)
{
error_set(err, QERR_UNSUPPORTED);
return 0;
}
/*
* Walk list of mounted file systems in the guest, and freeze the ones which
* are real local file systems.
*/
int64_t qmp_guest_fsfreeze_freeze(Error **err)
{
error_set(err, QERR_UNSUPPORTED);
return 0;
}
/*
* Walk list of frozen file systems in the guest, and thaw them.
*/
int64_t qmp_guest_fsfreeze_thaw(Error **err)
{
error_set(err, QERR_UNSUPPORTED);
return 0;
}
#endif
/* register init/cleanup routines for stateful command groups */
void ga_command_state_init(GAState *s, GACommandState *cs)
{
ga_state = s;
#if defined(CONFIG_FSFREEZE)
ga_command_state_add(cs, guest_fsfreeze_init, guest_fsfreeze_cleanup);
#endif
ga_command_state_add(cs, guest_file_init, NULL);
}