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 "ctree.h"
  25 #include "commands.h"
  26 #include "utils.h"
  27 #include "props.h"
  28
  29 #define XATTR_BTRFS_PREFIX     "btrfs."
  30 #define XATTR_BTRFS_PREFIX_LEN (sizeof(XATTR_BTRFS_PREFIX) - 1)
  31
  32 /*
  33  * Defined as synonyms in attr/xattr.h
  34  */
  35 #ifndef ENOATTR
  36 #define ENOATTR ENODATA
  37 #endif
  38
  39 static int prop_read_only(enum prop_object_type type,
  40                           const char *object,
  41                           const char *name,
  42                           const char *value)
  43 {
  44         int ret = 0;
  45         int fd = -1;
  46         u64 flags = 0;
  47
  48         fd = open(object, O_RDONLY);
  49         if (fd < 0) {
  50                 ret = -errno;
  51                 fprintf(stderr, "ERROR: open %s failed. %s\n",
  52                                 object, strerror(-ret));
  53                 goto out;
  54         }
  55
  56         ret = ioctl(fd, BTRFS_IOC_SUBVOL_GETFLAGS, &flags);
  57         if (ret < 0) {
  58                 ret = -errno;
  59                 fprintf(stderr, "ERROR: failed to get flags for %s. %s\n",
  60                                 object, strerror(-ret));
  61                 goto out;
  62         }
  63
  64         if (!value) {
  65                 if (flags & BTRFS_SUBVOL_RDONLY)
  66                         fprintf(stdout, "ro=true\n");
  67                 else
  68                         fprintf(stdout, "ro=false\n");
  69                 ret = 0;
  70                 goto out;
  71         }
  72
  73         if (!strcmp(value, "true")) {
  74                 flags |= BTRFS_SUBVOL_RDONLY;
  75         } else if (!strcmp(value, "false")) {
  76                 flags = flags & ~BTRFS_SUBVOL_RDONLY;
  77         } else {
  78                 ret = -EINVAL;
  79                 fprintf(stderr, "ERROR: invalid value for property.\n");
  80                 goto out;
  81         }
  82
  83         ret = ioctl(fd, BTRFS_IOC_SUBVOL_SETFLAGS, &flags);
  84         if (ret < 0) {
  85                 ret = -errno;
  86                 fprintf(stderr, "ERROR: failed to set flags for %s. %s\n",
  87                                 object, strerror(-ret));
  88                 goto out;
  89         }
  90
  91 out:
  92         if (fd != -1)
  93                 close(fd);
  94         return ret;
  95 }
  96
  97 static int prop_label(enum prop_object_type type,
  98                       const char *object,
  99                       const char *name,
 100                       const char *value)
 101 {
 102         int ret;
 103
 104         if (value) {
 105                 ret = set_label((char *) object, (char *) value);
 106         } else {
 107                 char label[BTRFS_LABEL_SIZE];
 108
 109                 ret = get_label((char *) object, label);
 110                 if (!ret)
 111                         fprintf(stdout, "label=%s\n", label);
 112         }
 113
 114         return ret;
 115 }
 116
 117 static int prop_compression(enum prop_object_type type,
 118                             const char *object,
 119                             const char *name,
 120                             const char *value)
 121 {
 122         int ret;
 123         ssize_t sret;
 124         int fd = -1;
 125         DIR *dirstream = NULL;
 126         char *buf = NULL;
 127         char *xattr_name = NULL;
 128         int open_flags = value ? O_RDWR : O_RDONLY;
 129
 130         fd = open_file_or_dir3(object, &dirstream, open_flags);
 131         if (fd == -1) {
 132                 ret = -errno;
 133                 fprintf(stderr, "ERROR: open %s failed. %s\n",
 134                         object, strerror(-ret));
 135                 goto out;
 136         }
 137
 138         xattr_name = malloc(XATTR_BTRFS_PREFIX_LEN + strlen(name) + 1);
 139         if (!xattr_name) {
 140                 ret = -ENOMEM;
 141                 goto out;
 142         }
 143         memcpy(xattr_name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN);
 144         memcpy(xattr_name + XATTR_BTRFS_PREFIX_LEN, name, strlen(name));
 145         xattr_name[XATTR_BTRFS_PREFIX_LEN + strlen(name)] = '\0';
 146
 147         if (value)
 148                 sret = fsetxattr(fd, xattr_name, value, strlen(value), 0);
 149         else
 150                 sret = fgetxattr(fd, xattr_name, NULL, 0);
 151         if (sret < 0) {
 152                 ret = -errno;
 153                 if (ret != -ENOATTR)
 154                         fprintf(stderr,
 155                                 "ERROR: failed to %s compression for %s. %s\n",
 156                                 value ? "set" : "get", object, strerror(-ret));
 157                 else
 158                         ret = 0;
 159                 goto out;
 160         }
 161         if (!value) {
 162                 size_t len = sret;
 163
 164                 buf = malloc(len);
 165                 if (!buf) {
 166                         ret = -ENOMEM;
 167                         goto out;
 168                 }
 169                 sret = fgetxattr(fd, xattr_name, buf, len);
 170                 if (sret < 0) {
 171                         ret = -errno;
 172                         fprintf(stderr,
 173                                 "ERROR: failed to get compression for %s. %s\n",
 174                                 object, strerror(-ret));
 175                         goto out;
 176                 }
 177                 fprintf(stdout, "compression=%.*s\n", (int)len, buf);
 178         }
 179
 180         ret = 0;
 181 out:
 182         free(xattr_name);
 183         free(buf);
 184         if (fd >= 0)
 185                 close_file_or_dir(fd, dirstream);
 186
 187         return ret;
 188 }
 189
 190 const struct prop_handler prop_handlers[] = {
 191         {"ro", "Set/get read-only flag of subvolume.", 0, prop_object_subvol,
 192          prop_read_only},
 193         {"label", "Set/get label of device.", 0,
 194          prop_object_dev | prop_object_root, prop_label},
 195         {"compression", "Set/get compression for a file or directory", 0,
 196          prop_object_inode, prop_compression},
 197         {NULL, NULL, 0, 0, NULL}
 198 };