1 files changed, 142 insertions, 0 deletions
diff --git a/src/core/load-dropin.c b/src/core/load-dropin.c
new file mode 100644
index 0000000..a50b200
--- /dev/null
+++ b/src/core/load-dropin.c
@@ -0,0 +1,142 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include "conf-parser.h"
+#include "fs-util.h"
+#include "load-dropin.h"
+#include "load-fragment.h"
+#include "log.h"
+#include "stat-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "unit-name.h"
+#include "unit.h"
+
+static int unit_name_compatible(const char *a, const char *b) {
+        _cleanup_free_ char *template = NULL;
+        int r;
+
+        /* The straightforward case: the symlink name matches the target */
+        if (streq(a, b))
+                return 1;
+
+        r = unit_name_template(a, &template);
+        if (r == -EINVAL)
+                return 0; /* Not a template */
+        if (r < 0)
+                return r; /* OOM, or some other failure. Just skip the warning. */
+
+        /* An instance name points to a target that is just the template name */
+        return streq(template, b);
+}
+
+static int process_deps(Unit *u, UnitDependency dependency, const char *dir_suffix) {
+        _cleanup_strv_free_ char **paths = NULL;
+        char **p;
+        int r;
+
+        r = unit_file_find_dropin_paths(NULL,
+                                        u->manager->lookup_paths.search_path,
+                                        u->manager->unit_path_cache,
+                                        dir_suffix,
+                                        NULL,
+                                        u->names,
+                                        &paths);
+        if (r < 0)
+                return r;
+
+        STRV_FOREACH(p, paths) {
+                _cleanup_free_ char *target = NULL;
+                const char *entry;
+
+                entry = basename(*p);
+
+                if (null_or_empty_path(*p) > 0) {
+                        /* an error usually means an invalid symlink, which is not a mask */
+                        log_unit_debug(u, "%s dependency on %s is masked by %s, ignoring.",
+                                       unit_dependency_to_string(dependency), entry, *p);
+                        continue;
+                }
+
+                r = is_symlink(*p);
+                if (r < 0) {
+                        log_unit_warning_errno(u, r, "%s dropin %s unreadable, ignoring: %m",
+                                               unit_dependency_to_string(dependency), *p);
+                        continue;
+                }
+                if (r == 0) {
+                        log_unit_warning(u, "%s dependency dropin %s is not a symlink, ignoring.",
+                                         unit_dependency_to_string(dependency), *p);
+                        continue;
+                }
+
+                if (!unit_name_is_valid(entry, UNIT_NAME_ANY)) {
+                        log_unit_warning(u, "%s dependency dropin %s is not a valid unit name, ignoring.",
+                                         unit_dependency_to_string(dependency), *p);
+                        continue;
+                }
+
+                r = readlink_malloc(*p, &target);
+                if (r < 0) {
+                        log_unit_warning_errno(u, r, "readlink(\"%s\") failed, ignoring: %m", *p);
+                        continue;
+                }
+
+                /* We don't treat this as an error, especially because we didn't check this for a
+                 * long time. Nevertheless, we warn, because such mismatch can be mighty confusing. */
+                r = unit_name_compatible(entry, basename(target));
+                if (r < 0) {
+                        log_unit_warning_errno(u, r, "Can't check if names %s and %s are compatible, ignoring: %m", entry, basename(target));
+                        continue;
+                }
+                if (r == 0)
+                        log_unit_warning(u, "%s dependency dropin %s target %s has different name",
+                                         unit_dependency_to_string(dependency), *p, target);
+
+                r = unit_add_dependency_by_name(u, dependency, entry, true, UNIT_DEPENDENCY_FILE);
+                if (r < 0)
+                        log_unit_warning_errno(u, r, "Cannot add %s dependency on %s, ignoring: %m",
+                                               unit_dependency_to_string(dependency), entry);
+        }
+
+        return 0;
+}
+
+int unit_load_dropin(Unit *u) {
+        _cleanup_strv_free_ char **l = NULL;
+        char **f;
+        int r;
+
+        assert(u);
+
+        /* Load dependencies from .wants and .requires directories */
+        r = process_deps(u, UNIT_WANTS, ".wants");
+        if (r < 0)
+                return r;
+
+        r = process_deps(u, UNIT_REQUIRES, ".requires");
+        if (r < 0)
+                return r;
+
+        /* Load .conf dropins */
+        r = unit_find_dropin_paths(u, &l);
+        if (r <= 0)
+                return 0;
+
+        if (!u->dropin_paths)
+                u->dropin_paths = TAKE_PTR(l);
+        else {
+                r = strv_extend_strv(&u->dropin_paths, l, true);
+                if (r < 0)
+                        return log_oom();
+        }
+
+        STRV_FOREACH(f, u->dropin_paths)
+                (void) config_parse(u->id, *f, NULL,
+                                    UNIT_VTABLE(u)->sections,
+                                    config_item_perf_lookup, load_fragment_gperf_lookup,
+                                    0, u);
+
+        u->dropin_mtime = now(CLOCK_REALTIME);
+
+        return 0;
+}