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