diff --git a/man/systemd-tmpfiles.xml b/man/systemd-tmpfiles.xml
index 998fd0911b..e3bb1db7c6 100644
--- a/man/systemd-tmpfiles.xml
+++ b/man/systemd-tmpfiles.xml
@@ -149,6 +149,7 @@
the specified prefix. This option can be specified multiple
times.
+
Ignore rules with paths that start with the
@@ -156,6 +157,16 @@
times.
+
+
+ A shortcut for --exclude-prefix=/dev --exclude-prefix=/proc
+ --exclude-prefix=/run --exclude-prefix=/sys, i.e. exclude the hierarchies typically backed
+ by virtual or memory file systems. This is useful in combination with , if
+ the specified directory tree contains an OS tree without these virtual/memory file systems mounted
+ in, as it is typically not desirable to create any files and directories below these subdirectories
+ if they are supposed to be overmounted during runtime.
+
+
Takes a directory path as an argument. All paths will be prefixed with the given alternate
@@ -164,7 +175,11 @@
When this option is used, the libc Name Service Switch (NSS) is bypassed for resolving users
and groups. Instead the files /etc/passwd and /etc/group
inside the alternate root are read directly. This means that users/groups not listed in these files
- will not be resolved, i.e. LDAP NIS and other complex databases are not considered.
+ will not be resolved, i.e. LDAP NIS and other complex databases are not considered.
+
+ Consider combining this with to ensure the invocation does not create files
+ or directories below mount points in the OS image operated on that are typically overmounted during
+ runtime.
diff --git a/src/tmpfiles/tmpfiles.c b/src/tmpfiles/tmpfiles.c
index 2404e36bf2..3c800d5fa8 100644
--- a/src/tmpfiles/tmpfiles.c
+++ b/src/tmpfiles/tmpfiles.c
@@ -2884,6 +2884,27 @@ static int cat_config(char **config_dirs, char **args) {
return cat_files(NULL, files, 0);
}
+static int exclude_default_prefixes(void) {
+ int r;
+
+ /* Provide an easy way to exclude virtual/memory file systems from what we do here. Useful in
+ * combination with --root= where we probably don't want to apply stuff to these dirs as they are
+ * likely over-mounted if the root directory is actually used, and it wouldbe less than ideal to have
+ * all kinds of files created/adjusted underneath these mount points. */
+
+ r = strv_extend_strv(
+ &arg_exclude_prefixes,
+ STRV_MAKE("/dev",
+ "/proc",
+ "/run",
+ "/sys"),
+ true);
+ if (r < 0)
+ return log_oom();
+
+ return 0;
+}
+
static int help(void) {
_cleanup_free_ char *link = NULL;
int r;
@@ -2904,6 +2925,7 @@ static int help(void) {
" --boot Execute actions only safe at boot\n"
" --prefix=PATH Only apply rules with the specified prefix\n"
" --exclude-prefix=PATH Ignore rules with the specified prefix\n"
+ " -E Ignore rules prefixed with /dev, /proc, /run, /sys\n"
" --root=PATH Operate on an alternate filesystem root\n"
" --replace=PATH Treat arguments as replacement for PATH\n"
" --no-pager Do not pipe output into a pager\n"
@@ -2954,7 +2976,7 @@ static int parse_argv(int argc, char *argv[]) {
assert(argc >= 0);
assert(argv);
- while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0)
+ while ((c = getopt_long(argc, argv, "hE", options, NULL)) >= 0)
switch (c) {
@@ -2998,6 +3020,13 @@ static int parse_argv(int argc, char *argv[]) {
return log_oom();
break;
+ case 'E':
+ r = exclude_default_prefixes();
+ if (r < 0)
+ return r;
+
+ break;
+
case ARG_ROOT:
r = parse_path_argument_and_warn(optarg, /* suppress_root= */ false, &arg_root);
if (r < 0)