props.c

   1 /*
   2  * This program is free software; you can redistribute it and/or
   3  * modify it under the terms of the GNU General Public
   4  * License v2 as published by the Free Software Foundation.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   9  * General Public License for more details.
  10  *
  11  * You should have received a copy of the GNU General Public
  12  * License along with this program; if not, write to the
  13  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  14  * Boston, MA 021110-1307, USA.
  15  */
  16
  17 #include <sys/stat.h>
  18 #include <sys/ioctl.h>
  19 #include <sys/types.h>
  20 #include <sys/xattr.h>
  21 #include <fcntl.h>
  22 #include <unistd.h>
  23
  24 #include <btrfsutil.h>
  25
  26 #include "ctree.h"
  27 #include "commands.h"
  28 #include "utils.h"
  29 #include "props.h"
  30
  31 #define XATTR_BTRFS_PREFIX     "btrfs."
  32 #define XATTR_BTRFS_PREFIX_LEN (sizeof(XATTR_BTRFS_PREFIX) - 1)
  33
  34 /*
  35  * Defined as synonyms in attr/xattr.h
  36  */
  37 #ifndef ENOATTR
  38 #define ENOATTR ENODATA
  39 #endif
  40
  41 static int prop_read_only(enum prop_object_type type,
  42                           const char *object,
  43                           const char *name,
  44                           const char *value)
  45 {
  46         enum btrfs_util_error err;
  47         bool read_only;
  48
  49         if (value) {
  50                 if (!strcmp(value, "true")) {
  51                         read_only = true;
  52                 } else if (!strcmp(value, "false")) {
  53                         read_only = false;
  54                 } else {
  55                         error("invalid value for property: %s", value);
  56                         return -EINVAL;
  57                 }
  58
  59                 err = btrfs_util_set_subvolume_read_only(object, read_only);
  60                 if (err) {
  61                         error_btrfs_util(err);
  62                         return -errno;
  63                 }
  64         } else {
  65                 err = btrfs_util_get_subvolume_read_only(object, &read_only);
  66                 if (err) {
  67                         error_btrfs_util(err);
  68                         return -errno;
  69                 }
  70
  71                 printf("ro=%s\n", read_only ? "true" : "false");
  72         }
  73
  74         return 0;
  75 }
  76
  77 static int prop_label(enum prop_object_type type,
  78                       const char *object,
  79                       const char *name,
  80                       const char *value)
  81 {
  82         int ret;
  83
  84         if (value) {
  85                 ret = set_label((char *) object, (char *) value);
  86         } else {
  87                 char label[BTRFS_LABEL_SIZE];
  88
  89                 ret = get_label((char *) object, label);
  90                 if (!ret)
  91                         fprintf(stdout, "label=%s\n", label);
  92         }
  93
  94         return ret;
  95 }
  96
  97 static int prop_compression(enum prop_object_type type,
  98                             const char *object,
  99                             const char *name,
 100                             const char *value)
 101 {
 102         int ret;
 103         ssize_t sret;
 104         int fd = -1;
 105         DIR *dirstream = NULL;
 106         char *buf = NULL;
 107         char *xattr_name = NULL;
 108         int open_flags = value ? O_RDWR : O_RDONLY;
 109
 110         fd = open_file_or_dir3(object, &dirstream, open_flags);
 111         if (fd == -1) {
 112                 ret = -errno;
 113                 error("failed to open %s: %s", object, strerror(-ret));
 114                 goto out;
 115         }
 116
 117         xattr_name = malloc(XATTR_BTRFS_PREFIX_LEN + strlen(name) + 1);
 118         if (!xattr_name) {
 119                 ret = -ENOMEM;
 120                 goto out;
 121         }
 122         memcpy(xattr_name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN);
 123         memcpy(xattr_name + XATTR_BTRFS_PREFIX_LEN, name, strlen(name));
 124         xattr_name[XATTR_BTRFS_PREFIX_LEN + strlen(name)] = '\0';
 125
 126         if (value) {
 127                 if (strcmp(value, "no") == 0 || strcmp(value, "none") == 0)
 128                         value = "";
 129                 sret = fsetxattr(fd, xattr_name, value, strlen(value), 0);
 130         } else {
 131                 sret = fgetxattr(fd, xattr_name, NULL, 0);
 132         }
 133         if (sret < 0) {
 134                 ret = -errno;
 135                 if (ret != -ENOATTR)
 136                         error("failed to %s compression for %s: %s",
 137                               value ? "set" : "get", object, strerror(-ret));
 138                 else
 139                         ret = 0;
 140                 goto out;
 141         }
 142         if (!value) {
 143                 size_t len = sret;
 144
 145                 buf = malloc(len);
 146                 if (!buf) {
 147                         ret = -ENOMEM;
 148                         goto out;
 149                 }
 150                 sret = fgetxattr(fd, xattr_name, buf, len);
 151                 if (sret < 0) {
 152                         ret = -errno;
 153                         error("failed to get compression for %s: %s",
 154                               object, strerror(-ret));
 155                         goto out;
 156                 }
 157                 fprintf(stdout, "compression=%.*s\n", (int)len, buf);
 158         }
 159
 160         ret = 0;
 161 out:
 162         free(xattr_name);
 163         free(buf);
 164         if (fd >= 0)
 165                 close_file_or_dir(fd, dirstream);
 166
 167         return ret;
 168 }
 169
 170 const struct prop_handler prop_handlers[] = {
 171         {"ro", "Set/get read-only flag of subvolume.", 0, prop_object_subvol,
 172          prop_read_only},
 173         {"label", "Set/get label of device.", 0,
 174          prop_object_dev | prop_object_root, prop_label},
 175         {"compression", "Set/get compression for a file or directory", 0,
 176          prop_object_inode, prop_compression},
 177         {NULL, NULL, 0, 0, NULL}
 178 };