[systemd-devel] [PATCH 2/3] tmpfiles: Add --root option to operate on an alternate fs tree.

[Michael Marineau]

This makes it possible to initialize or cleanup an arbitrary filesystem
hierarchy in the same way that it would be during system boot.
---
 src/tmpfiles/tmpfiles.c | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/src/tmpfiles/tmpfiles.c b/src/tmpfiles/tmpfiles.c
index 3684289..4ce35b5 100644
--- a/src/tmpfiles/tmpfiles.c
+++ b/src/tmpfiles/tmpfiles.c
@@ -111,6 +111,7 @@ static bool arg_boot = false;
 
 static char **include_prefixes = NULL;
 static char **exclude_prefixes = NULL;
+static char *arg_root = NULL;
 
 static const char conf_file_dirs[] =
         "/etc/tmpfiles.d\0"
@@ -1188,6 +1189,15 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
         if (!should_include_path(i->path))
                 return 0;
 
+        if (arg_root) {
+                char *p = strjoin(arg_root, i->path, NULL);
+                if (!p)
+                        return log_oom();
+
+                free(i->path);
+                i->path = p;
+        }
+
         if (user && !streq(user, "-")) {
                 const char *u = user;
 
@@ -1277,7 +1287,8 @@ static int help(void) {
                "     --remove               Remove marked files/directories\n"
                "     --boot                 Execute actions only safe at boot\n"
                "     --prefix=PATH          Only apply rules that apply to paths with the specified prefix\n"
-               "     --exclude-prefix=PATH  Ignore rules that apply to paths with the specified prefix\n",
+               "     --exclude-prefix=PATH  Ignore rules that apply to paths with the specified prefix\n"
+               "     --root=PATH            Operate on an alternate filesystem root\n",
                program_invocation_short_name);
 
         return 0;
@@ -1293,6 +1304,7 @@ static int parse_argv(int argc, char *argv[]) {
                 ARG_BOOT,
                 ARG_PREFIX,
                 ARG_EXCLUDE_PREFIX,
+                ARG_ROOT,
         };
 
         static const struct option options[] = {
@@ -1304,6 +1316,7 @@ static int parse_argv(int argc, char *argv[]) {
                 { "boot",           no_argument,         NULL, ARG_BOOT           },
                 { "prefix",         required_argument,   NULL, ARG_PREFIX         },
                 { "exclude-prefix", required_argument,   NULL, ARG_EXCLUDE_PREFIX },
+                { "root",           required_argument,   NULL, ARG_ROOT           },
                 {}
         };
 
@@ -1350,6 +1363,13 @@ static int parse_argv(int argc, char *argv[]) {
                                 return log_oom();
                         break;
 
+                case ARG_ROOT:
+                        arg_root = path_make_absolute_cwd(optarg);
+                        if (!arg_root)
+                                return log_oom();
+                        path_kill_slashes(arg_root);
+                        break;
+
                 case '?':
                         return -EINVAL;
 
@@ -1376,7 +1396,7 @@ static int read_config_file(const char *fn, bool ignore_enoent) {
 
         assert(fn);
 
-        r = search_and_fopen_nulstr(fn, "re", NULL, conf_file_dirs, &f);
+        r = search_and_fopen_nulstr(fn, "re", arg_root, conf_file_dirs, &f);
         if (r < 0) {
                 if (ignore_enoent && r == -ENOENT)
                         return 0;
@@ -1477,7 +1497,7 @@ int main(int argc, char *argv[]) {
                 _cleanup_strv_free_ char **files = NULL;
                 char **f;
 
-                r = conf_files_list_nulstr(&files, ".conf", NULL, conf_file_dirs);
+                r = conf_files_list_nulstr(&files, ".conf", arg_root, conf_file_dirs);
                 if (r < 0) {
                         log_error("Failed to enumerate tmpfiles.d files: %s", strerror(-r));
                         goto finish;
@@ -1508,6 +1528,7 @@ finish:
 
         free(include_prefixes);
         free(exclude_prefixes);
+        free(arg_root);
 
         set_free_free(unix_sockets);
 
-- 
1.8.3.2