src/home/homework-mount.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <sched.h>
   4 #include <sys/mount.h>
   5
   6 #include "alloc-util.h"
   7 #include "homework-mount.h"
   8 #include "mkdir.h"
   9 #include "mount-util.h"
  10 #include "path-util.h"
  11 #include "string-util.h"
  12
  13 static const char *mount_options_for_fstype(const char *fstype) {
  14         if (streq(fstype, "ext4"))
  15                 return "noquota,user_xattr";
  16         if (streq(fstype, "xfs"))
  17                 return "noquota";
  18         if (streq(fstype, "btrfs"))
  19                 return "noacl";
  20         return NULL;
  21 }
  22
  23 int home_mount_node(const char *node, const char *fstype, bool discard, unsigned long flags) {
  24         _cleanup_free_ char *joined = NULL;
  25         const char *options, *discard_option;
  26         int r;
  27
  28         options = mount_options_for_fstype(fstype);
  29
  30         discard_option = discard ? "discard" : "nodiscard";
  31
  32         if (options) {
  33                 joined = strjoin(options, ",", discard_option);
  34                 if (!joined)
  35                         return log_oom();
  36
  37                 options = joined;
  38         } else
  39                 options = discard_option;
  40
  41         r = mount_verbose(LOG_ERR, node, "/run/systemd/user-home-mount", fstype, flags|MS_RELATIME, strempty(options));
  42         if (r < 0)
  43                 return r;
  44
  45         log_info("Mounting file system completed.");
  46         return 0;
  47 }
  48
  49 int home_unshare_and_mount(const char *node, const char *fstype, bool discard, unsigned long flags) {
  50         int r;
  51
  52         if (unshare(CLONE_NEWNS) < 0)
  53                 return log_error_errno(errno, "Couldn't unshare file system namespace: %m");
  54
  55         r = mount_verbose(LOG_ERR, "/run", "/run", NULL, MS_SLAVE|MS_REC, NULL); /* Mark /run as MS_SLAVE in our new namespace */
  56         if (r < 0)
  57                 return r;
  58
  59         (void) mkdir_p("/run/systemd/user-home-mount", 0700);
  60
  61         if (node)
  62                 return home_mount_node(node, fstype, discard, flags);
  63
  64         return 0;
  65 }
  66
  67 int home_move_mount(const char *user_name_and_realm, const char *target) {
  68         _cleanup_free_ char *subdir = NULL;
  69         const char *d;
  70         int r;
  71
  72         assert(user_name_and_realm);
  73         assert(target);
  74
  75         if (user_name_and_realm) {
  76                 subdir = path_join("/run/systemd/user-home-mount/", user_name_and_realm);
  77                 if (!subdir)
  78                         return log_oom();
  79
  80                 d = subdir;
  81         } else
  82                 d = "/run/systemd/user-home-mount/";
  83
  84         (void) mkdir_p(target, 0700);
  85
  86         r = mount_verbose(LOG_ERR, d, target, NULL, MS_BIND, NULL);
  87         if (r < 0)
  88                 return r;
  89
  90         r = umount_verbose("/run/systemd/user-home-mount");
  91         if (r < 0)
  92                 return r;
  93
  94         log_info("Moving to final mount point %s completed.", target);
  95         return 0;
  96 }