src/core/load-dropin.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include "conf-parser.h"
   4 #include "dropin.h"
   5 #include "fs-util.h"
   6 #include "load-dropin.h"
   7 #include "load-fragment.h"
   8 #include "log.h"
   9 #include "manager.h"
  10 #include "path-util.h"
  11 #include "stat-util.h"
  12 #include "strv.h"
  13 #include "unit.h"
  14 #include "unit-name.h"
  15
  16 int unit_find_dropin_paths(Unit *u, bool use_unit_path_cache, char ***paths) {
  17         assert(u);
  18
  19         return unit_file_find_dropin_paths(NULL,
  20                                            u->manager->lookup_paths.search_path,
  21                                            use_unit_path_cache ? u->manager->unit_path_cache : NULL,
  22                                            ".d", ".conf",
  23                                            u->id, u->aliases,
  24                                            paths);
  25 }
  26
  27 static int process_deps(Unit *u, UnitDependency dependency, const char *dir_suffix) {
  28         _cleanup_strv_free_ char **paths = NULL;
  29         int r;
  30
  31         r = unit_file_find_dropin_paths(NULL,
  32                                         u->manager->lookup_paths.search_path,
  33                                         u->manager->unit_path_cache,
  34                                         dir_suffix, NULL,
  35                                         u->id, u->aliases,
  36                                         &paths);
  37         if (r < 0)
  38                 return r;
  39
  40         STRV_FOREACH(p, paths) {
  41                 _cleanup_free_ char *target = NULL, *target_file = NULL, *entry = NULL;
  42
  43                 if (null_or_empty_path(*p) > 0) {
  44                         /* an error usually means an invalid symlink, which is not a mask */
  45                         log_unit_debug(u, "%s dependency on %s is masked by %s, ignoring.",
  46                                        unit_dependency_to_string(dependency), entry, *p);
  47                         continue;
  48                 }
  49
  50                 r = is_symlink(*p);
  51                 if (r < 0) {
  52                         log_unit_warning_errno(u, r, "%s dropin %s unreadable, ignoring: %m",
  53                                                unit_dependency_to_string(dependency), *p);
  54                         continue;
  55                 }
  56                 if (r == 0) {
  57                         log_unit_warning(u, "%s dependency dropin %s is not a symlink, ignoring.",
  58                                          unit_dependency_to_string(dependency), *p);
  59                         continue;
  60                 }
  61
  62                 r = path_extract_filename(*p, &entry);
  63                 if (r < 0) {
  64                         log_unit_warning_errno(u, r, "Failed to extract file name of %s dependency dropin %s, ignoring: %m",
  65                                                unit_dependency_to_string(dependency), *p);
  66                         continue;
  67                 }
  68
  69                 if (!unit_name_is_valid(entry, UNIT_NAME_ANY)) {
  70                         log_unit_warning(u, "%s dependency dropin %s is not a valid unit name, ignoring.",
  71                                          unit_dependency_to_string(dependency), *p);
  72                         continue;
  73                 }
  74
  75                 r = readlink_malloc(*p, &target);
  76                 if (r < 0) {
  77                         log_unit_warning_errno(u, r, "readlink(\"%s\") failed, ignoring: %m", *p);
  78                         continue;
  79                 }
  80
  81                 r = path_extract_filename(target, &target_file);
  82                 if (r < 0) {
  83                         log_unit_warning_errno(u, r, "Failed to extract file name for dropin target %s, ignoring: %m",
  84                                                target);
  85                         continue;
  86                 }
  87
  88                 /* We don't treat this as an error, especially because we didn't check this for a
  89                  * long time. Nevertheless, we warn, because such mismatch can be mighty confusing. */
  90                 r = unit_symlink_name_compatible(entry, target_file, u->instance);
  91                 if (r < 0) {
  92                         log_unit_warning_errno(u, r, "Can't check if names %s and %s are compatible, ignoring: %m",
  93                                                entry, target_file);
  94                         continue;
  95                 }
  96                 if (r == 0)
  97                         log_unit_warning(u, "%s dependency dropin %s target %s has different name",
  98                                          unit_dependency_to_string(dependency), *p, target);
  99
 100                 r = unit_add_dependency_by_name(u, dependency, entry, true, UNIT_DEPENDENCY_FILE);
 101                 if (r < 0)
 102                         log_unit_warning_errno(u, r, "Cannot add %s dependency on %s, ignoring: %m",
 103                                                unit_dependency_to_string(dependency), entry);
 104         }
 105
 106         return 0;
 107 }
 108
 109 int unit_load_dropin(Unit *u) {
 110         _cleanup_strv_free_ char **l = NULL;
 111         int r;
 112
 113         assert(u);
 114
 115         /* Load dependencies from .wants, .requires and .upholds directories */
 116         r = process_deps(u, UNIT_WANTS, ".wants");
 117         if (r < 0)
 118                 return r;
 119
 120         r = process_deps(u, UNIT_REQUIRES, ".requires");
 121         if (r < 0)
 122                 return r;
 123
 124         r = process_deps(u, UNIT_UPHOLDS, ".upholds");
 125         if (r < 0)
 126                 return r;
 127
 128         /* Load .conf dropins */
 129         r = unit_find_dropin_paths(u, /* use_unit_path_cache = */ true, &l);
 130         if (r <= 0)
 131                 return 0;
 132
 133         r = strv_extend_strv_consume(&u->dropin_paths, TAKE_PTR(l), /* filter_duplicates = */ true);
 134         if (r < 0)
 135                 return log_oom();
 136
 137         u->dropin_mtime = 0;
 138         STRV_FOREACH(f, u->dropin_paths) {
 139                 struct stat st;
 140
 141                 r = config_parse(u->id, *f, NULL,
 142                                  UNIT_VTABLE(u)->sections,
 143                                  config_item_perf_lookup, load_fragment_gperf_lookup,
 144                                  0, u, &st);
 145                 if (r > 0)
 146                         u->dropin_mtime = MAX(u->dropin_mtime, timespec_load(&st.st_mtim));
 147         }
 148
 149         return 0;
 150 }