]> git.ipfire.org Git - thirdparty/systemd.git/blobdiff - src/basic/mount-util.c
Add SPDX license identifiers to source files under the LGPL
[thirdparty/systemd.git] / src / basic / mount-util.c
index c8f8022578e81e60fd104cc0e5c1662f316e7683..8801e2f8f1f8ea4a3ff521f2bd87c52a6758b3f0 100644 (file)
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 /***
   This file is part of systemd.
 
@@ -29,6 +30,7 @@
 #include "escape.h"
 #include "fd-util.h"
 #include "fileio.h"
+#include "fs-util.h"
 #include "hashmap.h"
 #include "mount-util.h"
 #include "parse-util.h"
@@ -111,9 +113,10 @@ int fd_is_mount_point(int fd, const char *filename, int flags) {
 
         r = name_to_handle_at(fd, filename, &h.handle, &mount_id, flags);
         if (r < 0) {
-                if (errno == ENOSYS)
-                        /* This kernel does not support name_to_handle_at()
-                         * fall back to simpler logic. */
+                if (IN_SET(errno, ENOSYS, EACCES, EPERM))
+                        /* This kernel does not support name_to_handle_at() at all, or the syscall was blocked (maybe
+                         * through seccomp, because we are running inside of a container?): fall back to simpler
+                         * logic. */
                         goto fallback_fdinfo;
                 else if (errno == EOPNOTSUPP)
                         /* This kernel or file system does not support
@@ -162,7 +165,7 @@ int fd_is_mount_point(int fd, const char *filename, int flags) {
 
 fallback_fdinfo:
         r = fd_fdinfo_mnt_id(fd, filename, flags, &mount_id);
-        if (IN_SET(r, -EOPNOTSUPP, -EACCES))
+        if (IN_SET(r, -EOPNOTSUPP, -EACCES, -EPERM))
                 goto fallback_fstat;
         if (r < 0)
                 return r;
@@ -205,9 +208,10 @@ fallback_fstat:
 }
 
 /* flags can be AT_SYMLINK_FOLLOW or 0 */
-int path_is_mount_point(const char *t, int flags) {
-        _cleanup_close_ int fd = -1;
+int path_is_mount_point(const char *t, const char *root, int flags) {
         _cleanup_free_ char *canonical = NULL, *parent = NULL;
+        _cleanup_close_ int fd = -1;
+        int r;
 
         assert(t);
 
@@ -219,9 +223,9 @@ int path_is_mount_point(const char *t, int flags) {
          * /bin -> /usr/bin/ and /usr is a mount point, then the parent that we
          * look at needs to be /usr, not /. */
         if (flags & AT_SYMLINK_FOLLOW) {
-                canonical = canonicalize_file_name(t);
-                if (!canonical)
-                        return -errno;
+                r = chase_symlinks(t, root, 0, &canonical);
+                if (r < 0)
+                        return r;
 
                 t = canonical;
         }
@@ -314,11 +318,16 @@ static int get_mount_flags(const char *path, unsigned long *flags) {
         return 0;
 }
 
-int bind_remount_recursive(const char *prefix, bool ro, char **blacklist) {
+/* Use this function only if do you have direct access to /proc/self/mountinfo
+ * and need the caller to open it for you. This is the case when /proc is
+ * masked or not mounted. Otherwise, use bind_remount_recursive. */
+int bind_remount_recursive_with_mountinfo(const char *prefix, bool ro, char **blacklist, FILE *proc_self_mountinfo) {
         _cleanup_set_free_free_ Set *done = NULL;
         _cleanup_free_ char *cleaned = NULL;
         int r;
 
+        assert(proc_self_mountinfo);
+
         /* Recursively remount a directory (and all its submounts) read-only or read-write. If the directory is already
          * mounted, we reuse the mount and simply mark it MS_BIND|MS_RDONLY (or remove the MS_RDONLY for read-write
          * operation). If it isn't we first make it one. Afterwards we apply MS_BIND|MS_RDONLY (or remove MS_RDONLY) to
@@ -341,7 +350,6 @@ int bind_remount_recursive(const char *prefix, bool ro, char **blacklist) {
                 return -ENOMEM;
 
         for (;;) {
-                _cleanup_fclose_ FILE *proc_self_mountinfo = NULL;
                 _cleanup_set_free_free_ Set *todo = NULL;
                 bool top_autofs = false;
                 char *x;
@@ -351,9 +359,7 @@ int bind_remount_recursive(const char *prefix, bool ro, char **blacklist) {
                 if (!todo)
                         return -ENOMEM;
 
-                proc_self_mountinfo = fopen("/proc/self/mountinfo", "re");
-                if (!proc_self_mountinfo)
-                        return -errno;
+                rewind(proc_self_mountinfo);
 
                 for (;;) {
                         _cleanup_free_ char *path = NULL, *p = NULL, *type = NULL;
@@ -467,14 +473,14 @@ int bind_remount_recursive(const char *prefix, bool ro, char **blacklist) {
                 while ((x = set_steal_first(todo))) {
 
                         r = set_consume(done, x);
-                        if (r == -EEXIST || r == 0)
+                        if (IN_SET(r, 0, -EEXIST))
                                 continue;
                         if (r < 0)
                                 return r;
 
                         /* Deal with mount points that are obstructed by a later mount */
-                        r = path_is_mount_point(x, 0);
-                        if (r == -ENOENT || r == 0)
+                        r = path_is_mount_point(x, NULL, 0);
+                        if (IN_SET(r, 0, -ENOENT))
                                 continue;
                         if (r < 0)
                                 return r;
@@ -492,6 +498,16 @@ int bind_remount_recursive(const char *prefix, bool ro, char **blacklist) {
         }
 }
 
+int bind_remount_recursive(const char *prefix, bool ro, char **blacklist) {
+        _cleanup_fclose_ FILE *proc_self_mountinfo = NULL;
+
+        proc_self_mountinfo = fopen("/proc/self/mountinfo", "re");
+        if (!proc_self_mountinfo)
+                return -errno;
+
+        return bind_remount_recursive_with_mountinfo(prefix, ro, blacklist, proc_self_mountinfo);
+}
+
 int mount_move_root(const char *path) {
         assert(path);
 
@@ -511,30 +527,67 @@ int mount_move_root(const char *path) {
 }
 
 bool fstype_is_network(const char *fstype) {
-        static const char table[] =
-                "afs\0"
-                "cifs\0"
-                "smbfs\0"
-                "sshfs\0"
-                "ncpfs\0"
-                "ncp\0"
-                "nfs\0"
-                "nfs4\0"
-                "gfs\0"
-                "gfs2\0"
-                "glusterfs\0"
-                "pvfs2\0" /* OrangeFS */
-                "ocfs2\0"
-                "lustre\0"
-                ;
-
         const char *x;
 
         x = startswith(fstype, "fuse.");
         if (x)
                 fstype = x;
 
-        return nulstr_contains(table, fstype);
+        return STR_IN_SET(fstype,
+                          "afs",
+                          "cifs",
+                          "smbfs",
+                          "sshfs",
+                          "ncpfs",
+                          "ncp",
+                          "nfs",
+                          "nfs4",
+                          "gfs",
+                          "gfs2",
+                          "glusterfs",
+                          "pvfs2", /* OrangeFS */
+                          "ocfs2",
+                          "lustre");
+}
+
+bool fstype_is_api_vfs(const char *fstype) {
+        return STR_IN_SET(fstype,
+                          "autofs",
+                          "bpf",
+                          "cgroup",
+                          "cgroup2",
+                          "configfs",
+                          "cpuset",
+                          "debugfs",
+                          "devpts",
+                          "devtmpfs",
+                          "efivarfs",
+                          "fusectl",
+                          "hugetlbfs",
+                          "mqueue",
+                          "proc",
+                          "pstore",
+                          "ramfs",
+                          "securityfs",
+                          "sysfs",
+                          "tmpfs",
+                          "tracefs");
+}
+
+bool fstype_is_ro(const char *fstype) {
+        /* All Linux file systems that are necessarily read-only */
+        return STR_IN_SET(fstype,
+                          "DM_verity_hash",
+                          "iso9660",
+                          "squashfs");
+}
+
+bool fstype_can_discard(const char *fstype) {
+        return STR_IN_SET(fstype,
+                          "btrfs",
+                          "ext4",
+                          "vfat",
+                          "xfs");
 }
 
 int repeat_unmount(const char *path, int flags) {
@@ -642,7 +695,7 @@ static char* mount_flags_to_string(long unsigned flags) {
                     FLAG(MS_I_VERSION),
                     FLAG(MS_STRICTATIME),
                     FLAG(MS_LAZYTIME),
-                    y, NULL);
+                    y);
         if (!x)
                 return NULL;
         if (!y)
@@ -671,6 +724,9 @@ int mount_verbose(
         else if ((flags & MS_BIND) && !type)
                 log_debug("Bind-mounting %s on %s (%s \"%s\")...",
                           what, where, strnull(fl), strempty(options));
+        else if (flags & MS_MOVE)
+                log_debug("Moving mount %s → %s (%s \"%s\")...",
+                          what, where, strnull(fl), strempty(options));
         else
                 log_debug("Mounting %s on %s (%s \"%s\")...",
                           strna(type), where, strnull(fl), strempty(options));
@@ -687,3 +743,35 @@ int umount_verbose(const char *what) {
                 return log_error_errno(errno, "Failed to unmount %s: %m", what);
         return 0;
 }
+
+const char *mount_propagation_flags_to_string(unsigned long flags) {
+
+        switch (flags & (MS_SHARED|MS_SLAVE|MS_PRIVATE)) {
+        case 0:
+                return "";
+        case MS_SHARED:
+                return "shared";
+        case MS_SLAVE:
+                return "slave";
+        case MS_PRIVATE:
+                return "private";
+        }
+
+        return NULL;
+}
+
+
+int mount_propagation_flags_from_string(const char *name, unsigned long *ret) {
+
+        if (isempty(name))
+                *ret = 0;
+        else if (streq(name, "shared"))
+                *ret = MS_SHARED;
+        else if (streq(name, "slave"))
+                *ret = MS_SLAVE;
+        else if (streq(name, "private"))
+                *ret = MS_PRIVATE;
+        else
+                return -EINVAL;
+        return 0;
+}