src/core/load-dropin.c

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