guest agent: add guest agent RPCs/commands
This adds the initial set of QMP/QAPI commands provided by the guest
agent:
guest-sync
guest-ping
guest-info
guest-shutdown
guest-file-open
guest-file-read
guest-file-write
guest-file-seek
guest-file-flush
guest-file-close
guest-fsfreeze-freeze
guest-fsfreeze-thaw
guest-fsfreeze-status
The input/output specification for these commands are documented in the
schema.
Example usage:
host:
qemu -device virtio-serial \
-chardev socket,path=/tmp/vs0.sock,server,nowait,id=qga0 \
-device virtserialport,chardev=qga0,name=org.qemu.quest_agent.0
...
echo "{'execute':'guest-info'}" | socat stdio unix-connect:/tmp/qga0.sock
guest:
qemu-ga -m virtio-serial -p /dev/virtio-ports/org.qemu.guest_agent.0 \
-p /var/run/qemu-guest-agent.pid -d
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Luiz Capitulino <lcapitulino@gmail.com>
diff --git a/qga/guest-agent-commands.c b/qga/guest-agent-commands.c
new file mode 100644
index 0000000..8c0d67e
--- /dev/null
+++ b/qga/guest-agent-commands.c
@@ -0,0 +1,518 @@
+/*
+ * 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>
+#include <mntent.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <linux/fs.h>
+#include "qga/guest-agent-core.h"
+#include "qga-qmp-commands.h"
+#include "qerror.h"
+#include "qemu-queue.h"
+
+static GAState *ga_state;
+
+static void disable_logging(void)
+{
+ ga_disable_logging(ga_state);
+}
+
+static void enable_logging(void)
+{
+ ga_enable_logging(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);
+}
+
+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");
+ }
+ }
+}
+
+/* register init/cleanup routines for stateful command groups */
+void ga_command_state_init(GAState *s, GACommandState *cs)
+{
+ ga_state = s;
+ ga_command_state_add(cs, guest_fsfreeze_init, guest_fsfreeze_cleanup);
+ ga_command_state_add(cs, guest_file_init, NULL);
+}