src/core/load-dropin.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   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 unit_name_compatible(const char *a, const char *b) {
  15         _cleanup_free_ char *template = NULL;
  16         int r;
  17
  18         /* The straightforward case: the symlink name matches the target */
  19         if (streq(a, b))
  20                 return 1;
  21
  22         r = unit_name_template(a, &template);
  23         if (r == -EINVAL)
  24                 return 0; /* Not a template */
  25         if (r < 0)
  26                 return r; /* OOM, or some other failure. Just skip the warning. */
  27
  28         /* An instance name points to a target that is just the template name */
  29         return streq(template, b);
  30 }
  31
  32 static int process_deps(Unit *u, UnitDependency dependency, const char *dir_suffix) {
  33         _cleanup_strv_free_ char **paths = NULL;
  34         char **p;
  35         int r;
  36
  37         r = unit_file_find_dropin_paths(NULL,
  38                                         u->manager->lookup_paths.search_path,
  39                                         u->manager->unit_path_cache,
  40                                         dir_suffix,
  41                                         NULL,
  42                                         u->names,
  43                                         &paths);
  44         if (r < 0)
  45                 return r;
  46
  47         STRV_FOREACH(p, paths) {
  48                 _cleanup_free_ char *target = NULL;
  49                 const char *entry;
  50
  51                 entry = basename(*p);
  52
  53                 if (null_or_empty_path(*p) > 0) {
  54                         /* an error usually means an invalid symlink, which is not a mask */
  55                         log_unit_debug(u, "%s dependency on %s is masked by %s, ignoring.",
  56                                        unit_dependency_to_string(dependency), entry, *p);
  57                         continue;
  58                 }
  59
  60                 r = is_symlink(*p);
  61                 if (r < 0) {
  62                         log_unit_warning_errno(u, r, "%s dropin %s unreadable, ignoring: %m",
  63                                                unit_dependency_to_string(dependency), *p);
  64                         continue;
  65                 }
  66                 if (r == 0) {
  67                         log_unit_warning(u, "%s dependency dropin %s is not a symlink, ignoring.",
  68                                          unit_dependency_to_string(dependency), *p);
  69                         continue;
  70                 }
  71
  72                 if (!unit_name_is_valid(entry, UNIT_NAME_ANY)) {
  73                         log_unit_warning(u, "%s dependency dropin %s is not a valid unit name, ignoring.",
  74                                          unit_dependency_to_string(dependency), *p);
  75                         continue;
  76                 }
  77
  78                 r = readlink_malloc(*p, &target);
  79                 if (r < 0) {
  80                         log_unit_warning_errno(u, r, "readlink(\"%s\") failed, ignoring: %m", *p);
  81                         continue;
  82                 }
  83
  84                 /* We don't treat this as an error, especially because we didn't check this for a
  85                  * long time. Nevertheless, we warn, because such mismatch can be mighty confusing. */
  86                 r = unit_name_compatible(entry, basename(target));
  87                 if (r < 0) {
  88                         log_unit_warning_errno(u, r, "Can't check if names %s and %s are compatible, ignoring: %m", entry, basename(target));
  89                         continue;
  90                 }
  91                 if (r == 0)
  92                         log_unit_warning(u, "%s dependency dropin %s target %s has different name",
  93                                          unit_dependency_to_string(dependency), *p, target);
  94
  95                 r = unit_add_dependency_by_name(u, dependency, entry, true, UNIT_DEPENDENCY_FILE);
  96                 if (r < 0)
  97                         log_unit_warning_errno(u, r, "Cannot add %s dependency on %s, ignoring: %m",
  98                                                unit_dependency_to_string(dependency), entry);
  99         }
 100
 101         return 0;
 102 }
 103
 104 int unit_load_dropin(Unit *u) {
 105         _cleanup_strv_free_ char **l = NULL;
 106         char **f;
 107         int r;
 108
 109         assert(u);
 110
 111         /* Load dependencies from .wants and .requires directories */
 112         r = process_deps(u, UNIT_WANTS, ".wants");
 113         if (r < 0)
 114                 return r;
 115
 116         r = process_deps(u, UNIT_REQUIRES, ".requires");
 117         if (r < 0)
 118                 return r;
 119
 120         /* Load .conf dropins */
 121         r = unit_find_dropin_paths(u, &l);
 122         if (r <= 0)
 123                 return 0;
 124
 125         if (!u->dropin_paths)
 126                 u->dropin_paths = TAKE_PTR(l);
 127         else {
 128                 r = strv_extend_strv(&u->dropin_paths, l, true);
 129                 if (r < 0)
 130                         return log_oom();
 131         }
 132
 133         STRV_FOREACH(f, u->dropin_paths)
 134                 (void) config_parse(u->id, *f, NULL,
 135                                     UNIT_VTABLE(u)->sections,
 136                                     config_item_perf_lookup, load_fragment_gperf_lookup,
 137                                     0, u);
 138
 139         u->dropin_mtime = now(CLOCK_REALTIME);
 140
 141         return 0;
 142 }