src/core/load-dropin.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2010 Lennart Poettering
   6 ***/
   7
   8
   9 #include "conf-parser.h"
  10 #include "fs-util.h"
  11 #include "load-dropin.h"
  12 #include "load-fragment.h"
  13 #include "log.h"
  14 #include "stat-util.h"
  15 #include "string-util.h"
  16 #include "strv.h"
  17 #include "unit-name.h"
  18 #include "unit.h"
  19
  20 static int unit_name_compatible(const char *a, const char *b) {
  21         _cleanup_free_ char *prefix = NULL;
  22         int r;
  23
  24         /* the straightforward case: the symlink name matches the target */
  25         if (streq(a, b))
  26                 return 1;
  27
  28         r = unit_name_template(a, &prefix);
  29         if (r == -EINVAL)
  30                 /* not a template */
  31                 return 0;
  32         if (r < 0)
  33                 /* oom, or some other failure. Just skip the warning. */
  34                 return r;
  35
  36         /* an instance name points to a target that is just the template name */
  37         if (streq(prefix, b))
  38                 return 1;
  39
  40         return 0;
  41 }
  42
  43 static int process_deps(Unit *u, UnitDependency dependency, const char *dir_suffix) {
  44         _cleanup_strv_free_ char **paths = NULL;
  45         char **p;
  46         int r;
  47
  48         r = unit_file_find_dropin_paths(NULL,
  49                                         u->manager->lookup_paths.search_path,
  50                                         u->manager->unit_path_cache,
  51                                         dir_suffix,
  52                                         NULL,
  53                                         u->names,
  54                                         &paths);
  55         if (r < 0)
  56                 return r;
  57
  58         STRV_FOREACH(p, paths) {
  59                 const char *entry;
  60                 _cleanup_free_ char *target = NULL;
  61
  62                 entry = basename(*p);
  63
  64                 if (null_or_empty_path(*p) > 0) {
  65                         /* an error usually means an invalid symlink, which is not a mask */
  66                         log_unit_debug(u, "%s dependency on %s is masked by %s, ignoring.",
  67                                        unit_dependency_to_string(dependency), entry, *p);
  68                         continue;
  69                 }
  70
  71                 r = is_symlink(*p);
  72                 if (r < 0) {
  73                         log_unit_warning_errno(u, r, "%s dropin %s unreadable, ignoring: %m",
  74                                                unit_dependency_to_string(dependency), *p);
  75                         continue;
  76                 }
  77                 if (r == 0) {
  78                         log_unit_warning(u, "%s dependency dropin %s is not a symlink, ignoring.",
  79                                          unit_dependency_to_string(dependency), *p);
  80                         continue;
  81                 }
  82
  83                 if (!unit_name_is_valid(entry, UNIT_NAME_ANY)) {
  84                         log_unit_warning(u, "%s dependency dropin %s is not a valid unit name, ignoring.",
  85                                          unit_dependency_to_string(dependency), *p);
  86                         continue;
  87                 }
  88
  89                 r = readlink_malloc(*p, &target);
  90                 if (r < 0) {
  91                         log_unit_warning_errno(u, r, "readlink(\"%s\") failed, ignoring: %m", *p);
  92                         continue;
  93                 }
  94
  95                 /* We don't treat this as an error, especially because we didn't check this for a
  96                  * long time. Nevertheless, we warn, because such mismatch can be mighty confusing. */
  97                 r = unit_name_compatible(entry, basename(target));
  98                 if (r < 0) {
  99                         log_unit_warning_errno(u, r, "Can't check if names %s and %s are compatible, ignoring: %m", entry, basename(target));
 100                         continue;
 101                 }
 102                 if (r == 0)
 103                         log_unit_warning(u, "%s dependency dropin %s target %s has different name",
 104                                          unit_dependency_to_string(dependency), *p, target);
 105
 106                 r = unit_add_dependency_by_name(u, dependency, entry, *p, true, UNIT_DEPENDENCY_FILE);
 107                 if (r < 0)
 108                         log_unit_warning_errno(u, r, "Cannot add %s dependency on %s, ignoring: %m",
 109                                                unit_dependency_to_string(dependency), entry);
 110         }
 111
 112         return 0;
 113 }
 114
 115 int unit_load_dropin(Unit *u) {
 116         _cleanup_strv_free_ char **l = NULL;
 117         char **f;
 118         int r;
 119
 120         assert(u);
 121
 122         /* Load dependencies from .wants and .requires directories */
 123         r = process_deps(u, UNIT_WANTS, ".wants");
 124         if (r < 0)
 125                 return r;
 126
 127         r = process_deps(u, UNIT_REQUIRES, ".requires");
 128         if (r < 0)
 129                 return r;
 130
 131         /* Load .conf dropins */
 132         r = unit_find_dropin_paths(u, &l);
 133         if (r <= 0)
 134                 return 0;
 135
 136         if (!u->dropin_paths)
 137                 u->dropin_paths = TAKE_PTR(l);
 138         else {
 139                 r = strv_extend_strv(&u->dropin_paths, l, true);
 140                 if (r < 0)
 141                         return log_oom();
 142         }
 143
 144         STRV_FOREACH(f, u->dropin_paths)
 145                 (void) config_parse(u->id, *f, NULL,
 146                                     UNIT_VTABLE(u)->sections,
 147                                     config_item_perf_lookup, load_fragment_gperf_lookup,
 148                                     0, u);
 149
 150         u->dropin_mtime = now(CLOCK_REALTIME);
 151
 152         return 0;
 153 }