1*518b0d80SAlexander Ivanov /*
2*518b0d80SAlexander Ivanov * QEMU Guest Agent Linux-specific command implementations
3*518b0d80SAlexander Ivanov *
4*518b0d80SAlexander Ivanov * Copyright IBM Corp. 2011
5*518b0d80SAlexander Ivanov *
6*518b0d80SAlexander Ivanov * Authors:
7*518b0d80SAlexander Ivanov * Michael Roth <mdroth@linux.vnet.ibm.com>
8*518b0d80SAlexander Ivanov * Michal Privoznik <mprivozn@redhat.com>
9*518b0d80SAlexander Ivanov *
10*518b0d80SAlexander Ivanov * This work is licensed under the terms of the GNU GPL, version 2 or later.
11*518b0d80SAlexander Ivanov * See the COPYING file in the top-level directory.
12*518b0d80SAlexander Ivanov */
13*518b0d80SAlexander Ivanov
14*518b0d80SAlexander Ivanov #include "qemu/osdep.h"
15*518b0d80SAlexander Ivanov #include "qapi/error.h"
16*518b0d80SAlexander Ivanov #include "commands-common.h"
17*518b0d80SAlexander Ivanov #include "cutils.h"
18*518b0d80SAlexander Ivanov #include <mntent.h>
19*518b0d80SAlexander Ivanov #include <sys/ioctl.h>
20*518b0d80SAlexander Ivanov
21*518b0d80SAlexander Ivanov #if defined(CONFIG_FSFREEZE) || defined(CONFIG_FSTRIM)
dev_major_minor(const char * devpath,unsigned int * devmajor,unsigned int * devminor)22*518b0d80SAlexander Ivanov static int dev_major_minor(const char *devpath,
23*518b0d80SAlexander Ivanov unsigned int *devmajor, unsigned int *devminor)
24*518b0d80SAlexander Ivanov {
25*518b0d80SAlexander Ivanov struct stat st;
26*518b0d80SAlexander Ivanov
27*518b0d80SAlexander Ivanov *devmajor = 0;
28*518b0d80SAlexander Ivanov *devminor = 0;
29*518b0d80SAlexander Ivanov
30*518b0d80SAlexander Ivanov if (stat(devpath, &st) < 0) {
31*518b0d80SAlexander Ivanov slog("failed to stat device file '%s': %s", devpath, strerror(errno));
32*518b0d80SAlexander Ivanov return -1;
33*518b0d80SAlexander Ivanov }
34*518b0d80SAlexander Ivanov if (S_ISDIR(st.st_mode)) {
35*518b0d80SAlexander Ivanov /* It is bind mount */
36*518b0d80SAlexander Ivanov return -2;
37*518b0d80SAlexander Ivanov }
38*518b0d80SAlexander Ivanov if (S_ISBLK(st.st_mode)) {
39*518b0d80SAlexander Ivanov *devmajor = major(st.st_rdev);
40*518b0d80SAlexander Ivanov *devminor = minor(st.st_rdev);
41*518b0d80SAlexander Ivanov return 0;
42*518b0d80SAlexander Ivanov }
43*518b0d80SAlexander Ivanov return -1;
44*518b0d80SAlexander Ivanov }
45*518b0d80SAlexander Ivanov
build_fs_mount_list_from_mtab(FsMountList * mounts,Error ** errp)46*518b0d80SAlexander Ivanov static bool build_fs_mount_list_from_mtab(FsMountList *mounts, Error **errp)
47*518b0d80SAlexander Ivanov {
48*518b0d80SAlexander Ivanov struct mntent *ment;
49*518b0d80SAlexander Ivanov FsMount *mount;
50*518b0d80SAlexander Ivanov char const *mtab = "/proc/self/mounts";
51*518b0d80SAlexander Ivanov FILE *fp;
52*518b0d80SAlexander Ivanov unsigned int devmajor, devminor;
53*518b0d80SAlexander Ivanov
54*518b0d80SAlexander Ivanov fp = setmntent(mtab, "r");
55*518b0d80SAlexander Ivanov if (!fp) {
56*518b0d80SAlexander Ivanov error_setg(errp, "failed to open mtab file: '%s'", mtab);
57*518b0d80SAlexander Ivanov return false;
58*518b0d80SAlexander Ivanov }
59*518b0d80SAlexander Ivanov
60*518b0d80SAlexander Ivanov while ((ment = getmntent(fp))) {
61*518b0d80SAlexander Ivanov /*
62*518b0d80SAlexander Ivanov * An entry which device name doesn't start with a '/' is
63*518b0d80SAlexander Ivanov * either a dummy file system or a network file system.
64*518b0d80SAlexander Ivanov * Add special handling for smbfs and cifs as is done by
65*518b0d80SAlexander Ivanov * coreutils as well.
66*518b0d80SAlexander Ivanov */
67*518b0d80SAlexander Ivanov if ((ment->mnt_fsname[0] != '/') ||
68*518b0d80SAlexander Ivanov (strcmp(ment->mnt_type, "smbfs") == 0) ||
69*518b0d80SAlexander Ivanov (strcmp(ment->mnt_type, "cifs") == 0)) {
70*518b0d80SAlexander Ivanov continue;
71*518b0d80SAlexander Ivanov }
72*518b0d80SAlexander Ivanov if (dev_major_minor(ment->mnt_fsname, &devmajor, &devminor) == -2) {
73*518b0d80SAlexander Ivanov /* Skip bind mounts */
74*518b0d80SAlexander Ivanov continue;
75*518b0d80SAlexander Ivanov }
76*518b0d80SAlexander Ivanov
77*518b0d80SAlexander Ivanov mount = g_new0(FsMount, 1);
78*518b0d80SAlexander Ivanov mount->dirname = g_strdup(ment->mnt_dir);
79*518b0d80SAlexander Ivanov mount->devtype = g_strdup(ment->mnt_type);
80*518b0d80SAlexander Ivanov mount->devmajor = devmajor;
81*518b0d80SAlexander Ivanov mount->devminor = devminor;
82*518b0d80SAlexander Ivanov
83*518b0d80SAlexander Ivanov QTAILQ_INSERT_TAIL(mounts, mount, next);
84*518b0d80SAlexander Ivanov }
85*518b0d80SAlexander Ivanov
86*518b0d80SAlexander Ivanov endmntent(fp);
87*518b0d80SAlexander Ivanov return true;
88*518b0d80SAlexander Ivanov }
89*518b0d80SAlexander Ivanov
decode_mntname(char * name,int len)90*518b0d80SAlexander Ivanov static void decode_mntname(char *name, int len)
91*518b0d80SAlexander Ivanov {
92*518b0d80SAlexander Ivanov int i, j = 0;
93*518b0d80SAlexander Ivanov for (i = 0; i <= len; i++) {
94*518b0d80SAlexander Ivanov if (name[i] != '\\') {
95*518b0d80SAlexander Ivanov name[j++] = name[i];
96*518b0d80SAlexander Ivanov } else if (name[i + 1] == '\\') {
97*518b0d80SAlexander Ivanov name[j++] = '\\';
98*518b0d80SAlexander Ivanov i++;
99*518b0d80SAlexander Ivanov } else if (name[i + 1] >= '0' && name[i + 1] <= '3' &&
100*518b0d80SAlexander Ivanov name[i + 2] >= '0' && name[i + 2] <= '7' &&
101*518b0d80SAlexander Ivanov name[i + 3] >= '0' && name[i + 3] <= '7') {
102*518b0d80SAlexander Ivanov name[j++] = (name[i + 1] - '0') * 64 +
103*518b0d80SAlexander Ivanov (name[i + 2] - '0') * 8 +
104*518b0d80SAlexander Ivanov (name[i + 3] - '0');
105*518b0d80SAlexander Ivanov i += 3;
106*518b0d80SAlexander Ivanov } else {
107*518b0d80SAlexander Ivanov name[j++] = name[i];
108*518b0d80SAlexander Ivanov }
109*518b0d80SAlexander Ivanov }
110*518b0d80SAlexander Ivanov }
111*518b0d80SAlexander Ivanov
112*518b0d80SAlexander Ivanov /*
113*518b0d80SAlexander Ivanov * Walk the mount table and build a list of local file systems
114*518b0d80SAlexander Ivanov */
build_fs_mount_list(FsMountList * mounts,Error ** errp)115*518b0d80SAlexander Ivanov bool build_fs_mount_list(FsMountList *mounts, Error **errp)
116*518b0d80SAlexander Ivanov {
117*518b0d80SAlexander Ivanov FsMount *mount;
118*518b0d80SAlexander Ivanov char const *mountinfo = "/proc/self/mountinfo";
119*518b0d80SAlexander Ivanov FILE *fp;
120*518b0d80SAlexander Ivanov char *line = NULL, *dash;
121*518b0d80SAlexander Ivanov size_t n;
122*518b0d80SAlexander Ivanov char check;
123*518b0d80SAlexander Ivanov unsigned int devmajor, devminor;
124*518b0d80SAlexander Ivanov int ret, dir_s, dir_e, type_s, type_e, dev_s, dev_e;
125*518b0d80SAlexander Ivanov
126*518b0d80SAlexander Ivanov fp = fopen(mountinfo, "r");
127*518b0d80SAlexander Ivanov if (!fp) {
128*518b0d80SAlexander Ivanov return build_fs_mount_list_from_mtab(mounts, errp);
129*518b0d80SAlexander Ivanov }
130*518b0d80SAlexander Ivanov
131*518b0d80SAlexander Ivanov while (getline(&line, &n, fp) != -1) {
132*518b0d80SAlexander Ivanov ret = sscanf(line, "%*u %*u %u:%u %*s %n%*s%n%c",
133*518b0d80SAlexander Ivanov &devmajor, &devminor, &dir_s, &dir_e, &check);
134*518b0d80SAlexander Ivanov if (ret < 3) {
135*518b0d80SAlexander Ivanov continue;
136*518b0d80SAlexander Ivanov }
137*518b0d80SAlexander Ivanov dash = strstr(line + dir_e, " - ");
138*518b0d80SAlexander Ivanov if (!dash) {
139*518b0d80SAlexander Ivanov continue;
140*518b0d80SAlexander Ivanov }
141*518b0d80SAlexander Ivanov ret = sscanf(dash, " - %n%*s%n %n%*s%n%c",
142*518b0d80SAlexander Ivanov &type_s, &type_e, &dev_s, &dev_e, &check);
143*518b0d80SAlexander Ivanov if (ret < 1) {
144*518b0d80SAlexander Ivanov continue;
145*518b0d80SAlexander Ivanov }
146*518b0d80SAlexander Ivanov line[dir_e] = 0;
147*518b0d80SAlexander Ivanov dash[type_e] = 0;
148*518b0d80SAlexander Ivanov dash[dev_e] = 0;
149*518b0d80SAlexander Ivanov decode_mntname(line + dir_s, dir_e - dir_s);
150*518b0d80SAlexander Ivanov decode_mntname(dash + dev_s, dev_e - dev_s);
151*518b0d80SAlexander Ivanov if (devmajor == 0) {
152*518b0d80SAlexander Ivanov /* btrfs reports major number = 0 */
153*518b0d80SAlexander Ivanov if (strcmp("btrfs", dash + type_s) != 0 ||
154*518b0d80SAlexander Ivanov dev_major_minor(dash + dev_s, &devmajor, &devminor) < 0) {
155*518b0d80SAlexander Ivanov continue;
156*518b0d80SAlexander Ivanov }
157*518b0d80SAlexander Ivanov }
158*518b0d80SAlexander Ivanov
159*518b0d80SAlexander Ivanov mount = g_new0(FsMount, 1);
160*518b0d80SAlexander Ivanov mount->dirname = g_strdup(line + dir_s);
161*518b0d80SAlexander Ivanov mount->devtype = g_strdup(dash + type_s);
162*518b0d80SAlexander Ivanov mount->devmajor = devmajor;
163*518b0d80SAlexander Ivanov mount->devminor = devminor;
164*518b0d80SAlexander Ivanov
165*518b0d80SAlexander Ivanov QTAILQ_INSERT_TAIL(mounts, mount, next);
166*518b0d80SAlexander Ivanov }
167*518b0d80SAlexander Ivanov free(line);
168*518b0d80SAlexander Ivanov
169*518b0d80SAlexander Ivanov fclose(fp);
170*518b0d80SAlexander Ivanov return true;
171*518b0d80SAlexander Ivanov }
172*518b0d80SAlexander Ivanov #endif /* CONFIG_FSFREEZE || CONFIG_FSTRIM */
173*518b0d80SAlexander Ivanov
174*518b0d80SAlexander Ivanov #ifdef CONFIG_FSFREEZE
175*518b0d80SAlexander Ivanov /*
176*518b0d80SAlexander Ivanov * Walk list of mounted file systems in the guest, and freeze the ones which
177*518b0d80SAlexander Ivanov * are real local file systems.
178*518b0d80SAlexander Ivanov */
qmp_guest_fsfreeze_do_freeze_list(bool has_mountpoints,strList * mountpoints,FsMountList mounts,Error ** errp)179*518b0d80SAlexander Ivanov int64_t qmp_guest_fsfreeze_do_freeze_list(bool has_mountpoints,
180*518b0d80SAlexander Ivanov strList *mountpoints,
181*518b0d80SAlexander Ivanov FsMountList mounts,
182*518b0d80SAlexander Ivanov Error **errp)
183*518b0d80SAlexander Ivanov {
184*518b0d80SAlexander Ivanov struct FsMount *mount;
185*518b0d80SAlexander Ivanov strList *list;
186*518b0d80SAlexander Ivanov int fd, ret, i = 0;
187*518b0d80SAlexander Ivanov
188*518b0d80SAlexander Ivanov QTAILQ_FOREACH_REVERSE(mount, &mounts, next) {
189*518b0d80SAlexander Ivanov /* To issue fsfreeze in the reverse order of mounts, check if the
190*518b0d80SAlexander Ivanov * mount is listed in the list here */
191*518b0d80SAlexander Ivanov if (has_mountpoints) {
192*518b0d80SAlexander Ivanov for (list = mountpoints; list; list = list->next) {
193*518b0d80SAlexander Ivanov if (strcmp(list->value, mount->dirname) == 0) {
194*518b0d80SAlexander Ivanov break;
195*518b0d80SAlexander Ivanov }
196*518b0d80SAlexander Ivanov }
197*518b0d80SAlexander Ivanov if (!list) {
198*518b0d80SAlexander Ivanov continue;
199*518b0d80SAlexander Ivanov }
200*518b0d80SAlexander Ivanov }
201*518b0d80SAlexander Ivanov
202*518b0d80SAlexander Ivanov fd = qga_open_cloexec(mount->dirname, O_RDONLY, 0);
203*518b0d80SAlexander Ivanov if (fd == -1) {
204*518b0d80SAlexander Ivanov error_setg_errno(errp, errno, "failed to open %s", mount->dirname);
205*518b0d80SAlexander Ivanov return -1;
206*518b0d80SAlexander Ivanov }
207*518b0d80SAlexander Ivanov
208*518b0d80SAlexander Ivanov /* we try to cull filesystems we know won't work in advance, but other
209*518b0d80SAlexander Ivanov * filesystems may not implement fsfreeze for less obvious reasons.
210*518b0d80SAlexander Ivanov * these will report EOPNOTSUPP. we simply ignore these when tallying
211*518b0d80SAlexander Ivanov * the number of frozen filesystems.
212*518b0d80SAlexander Ivanov * if a filesystem is mounted more than once (aka bind mount) a
213*518b0d80SAlexander Ivanov * consecutive attempt to freeze an already frozen filesystem will
214*518b0d80SAlexander Ivanov * return EBUSY.
215*518b0d80SAlexander Ivanov *
216*518b0d80SAlexander Ivanov * any other error means a failure to freeze a filesystem we
217*518b0d80SAlexander Ivanov * expect to be freezable, so return an error in those cases
218*518b0d80SAlexander Ivanov * and return system to thawed state.
219*518b0d80SAlexander Ivanov */
220*518b0d80SAlexander Ivanov ret = ioctl(fd, FIFREEZE);
221*518b0d80SAlexander Ivanov if (ret == -1) {
222*518b0d80SAlexander Ivanov if (errno != EOPNOTSUPP && errno != EBUSY) {
223*518b0d80SAlexander Ivanov error_setg_errno(errp, errno, "failed to freeze %s",
224*518b0d80SAlexander Ivanov mount->dirname);
225*518b0d80SAlexander Ivanov close(fd);
226*518b0d80SAlexander Ivanov return -1;
227*518b0d80SAlexander Ivanov }
228*518b0d80SAlexander Ivanov } else {
229*518b0d80SAlexander Ivanov i++;
230*518b0d80SAlexander Ivanov }
231*518b0d80SAlexander Ivanov close(fd);
232*518b0d80SAlexander Ivanov }
233*518b0d80SAlexander Ivanov return i;
234*518b0d80SAlexander Ivanov }
235*518b0d80SAlexander Ivanov
qmp_guest_fsfreeze_do_thaw(Error ** errp)236*518b0d80SAlexander Ivanov int qmp_guest_fsfreeze_do_thaw(Error **errp)
237*518b0d80SAlexander Ivanov {
238*518b0d80SAlexander Ivanov int ret;
239*518b0d80SAlexander Ivanov FsMountList mounts;
240*518b0d80SAlexander Ivanov FsMount *mount;
241*518b0d80SAlexander Ivanov int fd, i = 0, logged;
242*518b0d80SAlexander Ivanov Error *local_err = NULL;
243*518b0d80SAlexander Ivanov
244*518b0d80SAlexander Ivanov QTAILQ_INIT(&mounts);
245*518b0d80SAlexander Ivanov if (!build_fs_mount_list(&mounts, &local_err)) {
246*518b0d80SAlexander Ivanov error_propagate(errp, local_err);
247*518b0d80SAlexander Ivanov return -1;
248*518b0d80SAlexander Ivanov }
249*518b0d80SAlexander Ivanov
250*518b0d80SAlexander Ivanov QTAILQ_FOREACH(mount, &mounts, next) {
251*518b0d80SAlexander Ivanov logged = false;
252*518b0d80SAlexander Ivanov fd = qga_open_cloexec(mount->dirname, O_RDONLY, 0);
253*518b0d80SAlexander Ivanov if (fd == -1) {
254*518b0d80SAlexander Ivanov continue;
255*518b0d80SAlexander Ivanov }
256*518b0d80SAlexander Ivanov /* we have no way of knowing whether a filesystem was actually unfrozen
257*518b0d80SAlexander Ivanov * as a result of a successful call to FITHAW, only that if an error
258*518b0d80SAlexander Ivanov * was returned the filesystem was *not* unfrozen by that particular
259*518b0d80SAlexander Ivanov * call.
260*518b0d80SAlexander Ivanov *
261*518b0d80SAlexander Ivanov * since multiple preceding FIFREEZEs require multiple calls to FITHAW
262*518b0d80SAlexander Ivanov * to unfreeze, continuing issuing FITHAW until an error is returned,
263*518b0d80SAlexander Ivanov * in which case either the filesystem is in an unfreezable state, or,
264*518b0d80SAlexander Ivanov * more likely, it was thawed previously (and remains so afterward).
265*518b0d80SAlexander Ivanov *
266*518b0d80SAlexander Ivanov * also, since the most recent successful call is the one that did
267*518b0d80SAlexander Ivanov * the actual unfreeze, we can use this to provide an accurate count
268*518b0d80SAlexander Ivanov * of the number of filesystems unfrozen by guest-fsfreeze-thaw, which
269*518b0d80SAlexander Ivanov * may * be useful for determining whether a filesystem was unfrozen
270*518b0d80SAlexander Ivanov * during the freeze/thaw phase by a process other than qemu-ga.
271*518b0d80SAlexander Ivanov */
272*518b0d80SAlexander Ivanov do {
273*518b0d80SAlexander Ivanov ret = ioctl(fd, FITHAW);
274*518b0d80SAlexander Ivanov if (ret == 0 && !logged) {
275*518b0d80SAlexander Ivanov i++;
276*518b0d80SAlexander Ivanov logged = true;
277*518b0d80SAlexander Ivanov }
278*518b0d80SAlexander Ivanov } while (ret == 0);
279*518b0d80SAlexander Ivanov close(fd);
280*518b0d80SAlexander Ivanov }
281*518b0d80SAlexander Ivanov
282*518b0d80SAlexander Ivanov free_fs_mount_list(&mounts);
283*518b0d80SAlexander Ivanov
284*518b0d80SAlexander Ivanov return i;
285*518b0d80SAlexander Ivanov }
286*518b0d80SAlexander Ivanov #endif /* CONFIG_FSFREEZE */
287