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