smbinfo: Add ability to query snapshots (previous versions)

 "smbinfo list-snapshots"

Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Paulo Alcantara <palcantara@suse.de>

diff --git a/smbinfo.c b/smbinfo.c
index 33fca95075f05e6f697da2b1f47793373b7ceaf8..adfd85e66a3dd66755a301d5a737d4b3b6453987 100644 (file)
--- a/smbinfo.c
+++ b/smbinfo.c
@@ -89,6 +89,8 @@ usage(char *name)
                "      Prints the security descriptor for a cifs file.\n"
                "  quota:\n"
                "      Prints the quota for a cifs file.\n"
+               "  list-snapshots:\n"
+               "      List the previous versions of the volume that backs this file.\n"
                "  fsctl-getobjid:\n"
                "      Prints the objectid of the file and GUID of the underlying volume.\n",
                name);
@@ -882,7 +884,6 @@ print_quota(unsigned char *sd)
        uint32_t u32, neo;
        uint64_t u64;
        struct timeval tv;
-       struct tm;
        int i, off = 0;
 
 one_more:
@@ -966,6 +967,109 @@ quota(int f)
        free(qi);
 }
 
+
+struct smb_snapshot_array {
+       int32_t number_of_snapshots;
+       int32_t number_of_snapshots_returned;
+       int32_t snapshot_array_size;
+       char snapshot_data[0];
+};
+
+
+#define GMT_NAME_LEN 24 /* length of a @GMT- name */
+#define GMT_FORMAT "@GMT-%Y.%m.%d-%H.%M.%S"
+
+#define NTFS_TIME_OFFSET ((unsigned long long)(369*365 + 89) * 24 * 3600 * 10000000)
+
+static void print_snapshots(struct smb_snapshot_array *psnap)
+{
+       int current_snapshot_entry = 0;
+       char gmt_token[GMT_NAME_LEN + 1] = {0};
+       int i;
+       int j = 0;
+       struct tm tm;
+       unsigned long long dce_time;
+
+       printf("Number of snapshots: %d Number of snapshots returned: %d\n",
+               psnap->number_of_snapshots,
+               psnap->number_of_snapshots_returned);
+       printf("Snapshot list in GMT (Coordinated UTC Time) and SMB format (100 nanosecond units needed for snapshot mounts):");
+       for (i = 0; i < psnap->snapshot_array_size; i++) {
+               if (psnap->snapshot_data[i] == '@') {
+                       j = 0;
+                       current_snapshot_entry++;
+                       printf("\n%d) GMT:", current_snapshot_entry);
+               }
+               if (psnap->snapshot_data[i] != 0) {
+                       gmt_token[j] = psnap->snapshot_data[i];
+                       j++;
+               }
+               if (j == GMT_NAME_LEN) {
+                       printf("%s", gmt_token);
+                       j = 0;
+                       strptime(gmt_token, GMT_FORMAT, &tm);
+                       dce_time = timegm(&tm) * 10000000 + NTFS_TIME_OFFSET;
+                       printf("\n   SMB3:%llu", dce_time);
+               }
+       }
+       printf("\n");
+}
+
+#define CIFS_ENUMERATE_SNAPSHOTS _IOR(CIFS_IOCTL_MAGIC, 6, struct smb_snapshot_array)
+
+#define MIN_SNAPSHOT_ARRAY_SIZE 16 /* See MS-SMB2 section 3.3.5.15.1 */
+
+static void
+list_snapshots(int f)
+{
+
+       struct smb_snapshot_array snap_inf;
+       struct smb_snapshot_array *buf;
+
+       /*
+        * When first field in structure we pass in here is zero, cifs.ko can
+        * recognize that this is the first query and that it must set the SMB3
+        * FSCTL response buffer size (in the request) to exactly 16 bytes
+        * (which is required by some servers to process the initial query)
+        */
+       snap_inf.number_of_snapshots = 0;
+       snap_inf.number_of_snapshots_returned = 0;
+       snap_inf.snapshot_array_size = sizeof(struct smb_snapshot_array);
+
+       /* Query the number of snapshots so we know how much to allocate */
+       if (ioctl(f, CIFS_ENUMERATE_SNAPSHOTS, &snap_inf) < 0) {
+               fprintf(stderr, "Querying snapshots failed with %s\n", strerror(errno));
+               exit(1);
+       }
+
+       if (snap_inf.number_of_snapshots == 0)
+               return;
+
+       /* Now that we know the size, query the list from the server */
+
+       buf = malloc(snap_inf.snapshot_array_size + MIN_SNAPSHOT_ARRAY_SIZE);
+
+       if (buf == NULL) {
+               printf("Failed, out of memory.\n");
+               exit(1);
+       }
+       /*
+        * first parm is non-zero which allows cifs.ko to recognize that this is
+        * the second query (it has to set response buf size larger)
+        */
+       buf->number_of_snapshots = snap_inf.number_of_snapshots;
+
+       buf->snapshot_array_size = snap_inf.snapshot_array_size;
+
+       if (ioctl(f, CIFS_ENUMERATE_SNAPSHOTS, buf) < 0) {
+               fprintf(stderr, "Querying snapshots failed with %s\n", strerror(errno));
+               exit(1);
+       }
+
+       print_snapshots(buf);
+       free(buf);
+}
+
 int main(int argc, char *argv[])
 {
        int c;
@@ -1016,6 +1120,8 @@ int main(int argc, char *argv[])
                secdesc(f);
        else if (!strcmp(argv[optind], "quota"))
                quota(f);
+       else if (!strcmp(argv[optind], "list-snapshots"))
+               list_snapshots(f);
        else if (!strcmp(argv[1], "fsctl-getobjid"))
                fsctlgetobjid(f);
        else {

diff --git a/smbinfo.rst b/smbinfo.rst
index fd7f0fff2a22d56d627d16ac6bf7ebeb020dee6d..0c96050ebe76e2caccd3c9471329178c443a4ea6 100644 (file)
--- a/smbinfo.rst
+++ b/smbinfo.rst
@@ -64,6 +64,8 @@ COMMAND
 
 `fsctl-getobjid`: Prints the ObjectID
 
+`list-snapshots`: Lists the previous versions of the volume that backs this file
+
 `quota`: Print the quota for the volume in the form
 - SID Length
 - Change Time