src/core/load-dropin.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2010 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20
  21 #include "conf-parser.h"
  22 #include "fs-util.h"
  23 #include "load-dropin.h"
  24 #include "load-fragment.h"
  25 #include "log.h"
  26 #include "stat-util.h"
  27 #include "string-util.h"
  28 #include "strv.h"
  29 #include "unit-name.h"
  30 #include "unit.h"
  31
  32 static int unit_name_compatible(const char *a, const char *b) {
  33         _cleanup_free_ char *prefix = NULL;
  34         int r;
  35
  36         /* the straightforward case: the symlink name matches the target */
  37         if (streq(a, b))
  38                 return 1;
  39
  40         r = unit_name_template(a, &prefix);
  41         if (r == -EINVAL)
  42                 /* not a template */
  43                 return 0;
  44         if (r < 0)
  45                 /* oom, or some other failure. Just skip the warning. */
  46                 return r;
  47
  48         /* an instance name points to a target that is just the template name */
  49         if (streq(prefix, b))
  50                 return 1;
  51
  52         return 0;
  53 }
  54
  55 static int process_deps(Unit *u, UnitDependency dependency, const char *dir_suffix) {
  56         _cleanup_strv_free_ char **paths = NULL;
  57         char **p;
  58         int r;
  59
  60         r = unit_file_find_dropin_paths(NULL,
  61                                         u->manager->lookup_paths.search_path,
  62                                         u->manager->unit_path_cache,
  63                                         dir_suffix,
  64                                         NULL,
  65                                         u->names,
  66                                         &paths);
  67         if (r < 0)
  68                 return r;
  69
  70         STRV_FOREACH(p, paths) {
  71                 const char *entry;
  72                 _cleanup_free_ char *target = NULL;
  73
  74                 entry = basename(*p);
  75
  76                 if (null_or_empty_path(*p) > 0) {
  77                         /* an error usually means an invalid symlink, which is not a mask */
  78                         log_unit_debug(u, "%s dependency on %s is masked by %s, ignoring.",
  79                                        unit_dependency_to_string(dependency), entry, *p);
  80                         continue;
  81                 }
  82
  83                 r = is_symlink(*p);
  84                 if (r < 0) {
  85                         log_unit_warning_errno(u, r, "%s dropin %s unreadable, ignoring: %m",
  86                                                unit_dependency_to_string(dependency), *p);
  87                         continue;
  88                 }
  89                 if (r == 0) {
  90                         log_unit_warning(u, "%s dependency dropin %s is not a symlink, ignoring.",
  91                                          unit_dependency_to_string(dependency), *p);
  92                         continue;
  93                 }
  94
  95                 if (!unit_name_is_valid(entry, UNIT_NAME_ANY)) {
  96                         log_unit_warning(u, "%s dependency dropin %s is not a valid unit name, ignoring.",
  97                                          unit_dependency_to_string(dependency), *p);
  98                         continue;
  99                 }
 100
 101                 r = readlink_malloc(*p, &target);
 102                 if (r < 0) {
 103                         log_unit_warning_errno(u, r, "readlink(\"%s\") failed, ignoring: %m", *p);
 104                         continue;
 105                 }
 106
 107                 /* We don't treat this as an error, especially because we didn't check this for a
 108                  * long time. Nevertheless, we warn, because such mismatch can be mighty confusing. */
 109                 r = unit_name_compatible(entry, basename(target));
 110                 if (r < 0) {
 111                         log_unit_warning_errno(u, r, "Can't check if names %s and %s are compatible, ignoring: %m", entry, basename(target));
 112                         continue;
 113                 }
 114                 if (r == 0)
 115                         log_unit_warning(u, "%s dependency dropin %s target %s has different name",
 116                                          unit_dependency_to_string(dependency), *p, target);
 117
 118                 r = unit_add_dependency_by_name(u, dependency, entry, *p, true, UNIT_DEPENDENCY_FILE);
 119                 if (r < 0)
 120                         log_unit_error_errno(u, r, "cannot add %s dependency on %s, ignoring: %m",
 121                                              unit_dependency_to_string(dependency), entry);
 122         }
 123
 124         return 0;
 125 }
 126
 127 int unit_load_dropin(Unit *u) {
 128         _cleanup_strv_free_ char **l = NULL;
 129         char **f;
 130         int r;
 131
 132         assert(u);
 133
 134         /* Load dependencies from .wants and .requires directories */
 135         r = process_deps(u, UNIT_WANTS, ".wants");
 136         if (r < 0)
 137                 return r;
 138
 139         r = process_deps(u, UNIT_REQUIRES, ".requires");
 140         if (r < 0)
 141                 return r;
 142
 143         /* Load .conf dropins */
 144         r = unit_find_dropin_paths(u, &l);
 145         if (r <= 0)
 146                 return 0;
 147
 148         if (!u->dropin_paths) {
 149                 u->dropin_paths = l;
 150                 l = NULL;
 151         } else {
 152                 r = strv_extend_strv(&u->dropin_paths, l, true);
 153                 if (r < 0)
 154                         return log_oom();
 155         }
 156
 157         STRV_FOREACH(f, u->dropin_paths)
 158                 (void) config_parse(u->id, *f, NULL,
 159                                     UNIT_VTABLE(u)->sections,
 160                                     config_item_perf_lookup, load_fragment_gperf_lookup,
 161                                     0, u);
 162
 163         u->dropin_mtime = now(CLOCK_REALTIME);
 164
 165         return 0;
 166 }