src/basic/chattr-util.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <fcntl.h>
   4 #include <sys/ioctl.h>
   5 #include <sys/stat.h>
   6
   7 #include "bitfield.h"
   8 #include "chattr-util.h"
   9 #include "errno-util.h"
  10 #include "fd-util.h"
  11 #include "fs-util.h"
  12 #include "log.h"
  13 #include "recurse-dir.h"
  14 #include "string-util.h"
  15
  16 int chattr_full(
  17               int dir_fd,
  18               const char *path,
  19               unsigned value,
  20               unsigned mask,
  21               unsigned *ret_previous,
  22               unsigned *ret_final,
  23               ChattrApplyFlags flags) {
  24
  25         _cleanup_close_ int fd = -EBADF;
  26         unsigned old_attr, new_attr;
  27         int set_flags_errno = 0;
  28         struct stat st;
  29
  30         assert(dir_fd >= 0 || dir_fd == AT_FDCWD);
  31
  32         fd = xopenat(dir_fd, path, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
  33         if (fd < 0)
  34                 return fd;
  35
  36         if (fstat(fd, &st) < 0)
  37                 return -errno;
  38
  39         /* Explicitly check whether this is a regular file or directory. If it is anything else (such
  40          * as a device node or fifo), then the ioctl will not hit the file systems but possibly
  41          * drivers, where the ioctl might have different effects. Notably, DRM is using the same
  42          * ioctl() number. */
  43
  44         if (!S_ISDIR(st.st_mode) && !S_ISREG(st.st_mode))
  45                 return -ENOTTY;
  46
  47         if (mask == 0 && !ret_previous && !ret_final)
  48                 return 0;
  49
  50         if (ioctl(fd, FS_IOC_GETFLAGS, &old_attr) < 0)
  51                 return -errno;
  52
  53         new_attr = (old_attr & ~mask) | (value & mask);
  54         if (new_attr == old_attr) {
  55                 if (ret_previous)
  56                         *ret_previous = old_attr;
  57                 if (ret_final)
  58                         *ret_final = old_attr;
  59                 return 0;
  60         }
  61
  62         if (ioctl(fd, FS_IOC_SETFLAGS, &new_attr) >= 0) {
  63                 unsigned attr;
  64
  65                 /* Some filesystems (BTRFS) silently fail when a flag cannot be set. Let's make sure our
  66                  * changes actually went through by querying the flags again and verifying they're equal to
  67                  * the flags we tried to configure. */
  68
  69                 if (ioctl(fd, FS_IOC_GETFLAGS, &attr) < 0)
  70                         return -errno;
  71
  72                 if (new_attr == attr) {
  73                         if (ret_previous)
  74                                 *ret_previous = old_attr;
  75                         if (ret_final)
  76                                 *ret_final = new_attr;
  77                         return 1;
  78                 }
  79
  80                 /* Trigger the fallback logic. */
  81                 errno = EINVAL;
  82         }
  83
  84         if (!ERRNO_IS_IOCTL_NOT_SUPPORTED(errno) || !FLAGS_SET(flags, CHATTR_FALLBACK_BITWISE))
  85                 return -errno;
  86
  87         /* When -EINVAL is returned, incompatible attributes might be simultaneously specified. E.g.,
  88          * compress(c) and nocow(C) attributes cannot be set to files on btrfs. As a fallback, let's try to
  89          * set attributes one by one.
  90          *
  91          * Alternatively, when we get EINVAL or EOPNOTSUPP (or a similar error code) we assume a flag might
  92          * just not be supported, and we can ignore it too */
  93
  94         unsigned current_attr = old_attr;
  95
  96         BIT_FOREACH(i, mask) {
  97                 unsigned new_one, mask_one = 1u << i;
  98
  99                 new_one = UPDATE_FLAG(current_attr, mask_one, FLAGS_SET(value, mask_one));
 100                 if (new_one == current_attr)
 101                         continue;
 102
 103                 if (ioctl(fd, FS_IOC_SETFLAGS, &new_one) < 0) {
 104                         if (!ERRNO_IS_IOCTL_NOT_SUPPORTED(errno))
 105                                 return -errno;
 106
 107                         log_full_errno(FLAGS_SET(flags, CHATTR_WARN_UNSUPPORTED_FLAGS) ? LOG_WARNING : LOG_DEBUG,
 108                                        errno,
 109                                        "Unable to set file attribute 0x%x on %s, ignoring: %m", mask_one, strna(path));
 110
 111                         /* Ensures that we record whether only EOPNOTSUPP&friends are encountered, or if a more serious
 112                          * error (thus worth logging at a different level, etc) was seen too. */
 113                         if (set_flags_errno == 0 || !ERRNO_IS_IOCTL_NOT_SUPPORTED(errno))
 114                                 set_flags_errno = -errno;
 115
 116                         continue;
 117                 }
 118
 119                 if (ioctl(fd, FS_IOC_GETFLAGS, &current_attr) < 0)
 120                         return -errno;
 121         }
 122
 123         if (ret_previous)
 124                 *ret_previous = old_attr;
 125         if (ret_final)
 126                 *ret_final = current_attr;
 127
 128         /* -ENOANO indicates that some attributes cannot be set. ERRNO_IS_IOCTL_NOT_SUPPORTED indicates that
 129          * all encountered failures were due to flags not supported by the FS, so return a specific error in
 130          * that case, so callers can handle it properly (e.g.: tmpfiles.d can use debug level logging). */
 131         return current_attr == new_attr ? 1 : ERRNO_IS_IOCTL_NOT_SUPPORTED(set_flags_errno) ? set_flags_errno : -ENOANO;
 132 }
 133
 134 int read_attr_fd(int fd, unsigned *ret) {
 135         struct stat st;
 136
 137         assert(fd >= 0);
 138         assert(ret);
 139
 140         if (fstat(fd, &st) < 0)
 141                 return -errno;
 142
 143         if (!S_ISDIR(st.st_mode) && !S_ISREG(st.st_mode))
 144                 return -ENOTTY;
 145
 146         _cleanup_close_ int fd_close = -EBADF;
 147         fd = fd_reopen_condition(fd, O_RDONLY|O_CLOEXEC|O_NOCTTY, O_PATH, &fd_close); /* drop O_PATH if it is set */
 148         if (fd < 0)
 149                 return fd;
 150
 151         return RET_NERRNO(ioctl(fd, FS_IOC_GETFLAGS, ret));
 152 }
 153
 154 int read_attr_at(int dir_fd, const char *path, unsigned *ret) {
 155         _cleanup_close_ int fd_close = -EBADF;
 156         int fd;
 157
 158         assert(dir_fd >= 0 || dir_fd == AT_FDCWD);
 159         assert(ret);
 160
 161         if (isempty(path) && dir_fd != AT_FDCWD)
 162                 fd = dir_fd;
 163         else {
 164                 fd_close = xopenat(dir_fd, path, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
 165                 if (fd_close < 0)
 166                         return fd_close;
 167
 168                 fd = fd_close;
 169         }
 170
 171         return read_attr_fd(fd, ret);
 172 }
 173
 174 int read_fs_xattr_fd(int fd, uint32_t *ret_xflags, uint32_t *ret_projid) {
 175         struct fsxattr attrs;
 176         _cleanup_close_ int fd_reopened = -EBADF;
 177
 178         assert(fd >= 0);
 179
 180         fd = fd_reopen_condition(fd, O_RDONLY|O_CLOEXEC|O_NOCTTY, O_PATH, &fd_reopened);
 181         if (fd < 0)
 182                 return fd;
 183
 184         if (ioctl(fd, FS_IOC_FSGETXATTR, &attrs) < 0)
 185                 return -errno;
 186
 187         if (ret_xflags)
 188                 *ret_xflags = attrs.fsx_xflags;
 189
 190         if (ret_projid)
 191                 *ret_projid = attrs.fsx_projid;
 192
 193         return 0;
 194 }
 195
 196 int set_proj_id(int fd, uint32_t proj_id) {
 197         struct fsxattr attrs;
 198         _cleanup_close_ int fd_reopened = -EBADF;
 199
 200         assert(fd >= 0);
 201
 202         fd = fd_reopen_condition(fd, O_RDONLY|O_CLOEXEC|O_NOCTTY, O_PATH, &fd_reopened);
 203         if (fd < 0)
 204                 return fd;
 205
 206         if (ioctl(fd, FS_IOC_FSGETXATTR, &attrs) < 0)
 207                 return -errno;
 208
 209         struct stat statbuf;
 210         if (fstat(fd, &statbuf) < 0)
 211                 return -errno;
 212
 213         if (attrs.fsx_projid == proj_id && (!S_ISDIR(statbuf.st_mode) || FLAGS_SET(attrs.fsx_xflags, FS_XFLAG_PROJINHERIT)))
 214                 return 0;
 215
 216         attrs.fsx_projid = proj_id;
 217         if (S_ISDIR(statbuf.st_mode))
 218                 attrs.fsx_xflags |= FS_XFLAG_PROJINHERIT;
 219
 220         return RET_NERRNO(ioctl(fd, FS_IOC_FSSETXATTR, &attrs));
 221 }
 222
 223 static int set_proj_id_cb(
 224                 RecurseDirEvent event,
 225                 const char *path,
 226                 int dir_fd,
 227                 int inode_fd,
 228                 const struct dirent *de,
 229                 const struct statx *sx,
 230                 void *userdata) {
 231
 232         if (!IN_SET(event, RECURSE_DIR_ENTER, RECURSE_DIR_ENTRY))
 233                 return RECURSE_DIR_CONTINUE;
 234
 235         if (de && !IN_SET(de->d_type, DT_DIR, DT_REG))
 236                 return RECURSE_DIR_CONTINUE;
 237
 238         return set_proj_id(inode_fd, PTR_TO_UINT32(userdata));
 239 }
 240
 241 int set_proj_id_recursive(int fd, uint32_t proj_id) {
 242         return recurse_dir_at(
 243                         fd,
 244                         /* path = */ NULL,
 245                         /* statx_mask = */ 0,
 246                         /* n_depth_max = */ UINT_MAX,
 247                         RECURSE_DIR_ENSURE_TYPE|RECURSE_DIR_TOPLEVEL|RECURSE_DIR_INODE_FD,
 248                         set_proj_id_cb,
 249                         UINT32_TO_PTR(proj_id));
 250 }