summaryrefslogtreecommitdiffstats
path: root/src/shared/dropin.c
blob: d46e8380440921994eac61837f7c519a8529633a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
/* SPDX-License-Identifier: LGPL-2.1-or-later */

#include <errno.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>

#include "alloc-util.h"
#include "chase.h"
#include "conf-files.h"
#include "dirent-util.h"
#include "dropin.h"
#include "escape.h"
#include "fd-util.h"
#include "fileio-label.h"
#include "hashmap.h"
#include "log.h"
#include "macro.h"
#include "mkdir.h"
#include "path-util.h"
#include "set.h"
#include "string-util.h"
#include "strv.h"
#include "unit-name.h"

int drop_in_file(const char *dir, const char *unit, unsigned level,
                 const char *name, char **ret_p, char **ret_q) {

        char prefix[DECIMAL_STR_MAX(unsigned)];
        _cleanup_free_ char *b = NULL, *p = NULL, *q = NULL;

        assert(unit);
        assert(name);
        assert(ret_p);
        assert(ret_q);

        sprintf(prefix, "%u", level);

        b = xescape(name, "/.");
        if (!b)
                return -ENOMEM;

        if (!filename_is_valid(b))
                return -EINVAL;

        p = strjoin(dir, "/", unit, ".d");
        q = strjoin(p, "/", prefix, "-", b, ".conf");
        if (!p || !q)
                return -ENOMEM;

        *ret_p = TAKE_PTR(p);
        *ret_q = TAKE_PTR(q);
        return 0;
}

int write_drop_in(const char *dir, const char *unit, unsigned level,
                  const char *name, const char *data) {

        _cleanup_free_ char *p = NULL, *q = NULL;
        int r;

        assert(dir);
        assert(unit);
        assert(name);
        assert(data);

        r = drop_in_file(dir, unit, level, name, &p, &q);
        if (r < 0)
                return r;

        (void) mkdir_p(p, 0755);
        return write_string_file_atomic_label(q, data);
}

int write_drop_in_format(const char *dir, const char *unit, unsigned level,
                         const char *name, const char *format, ...) {
        _cleanup_free_ char *p = NULL;
        va_list ap;
        int r;

        assert(dir);
        assert(unit);
        assert(name);
        assert(format);

        va_start(ap, format);
        r = vasprintf(&p, format, ap);
        va_end(ap);

        if (r < 0)
                return -ENOMEM;

        return write_drop_in(dir, unit, level, name, p);
}

static int unit_file_add_dir(
                const char *original_root,
                const char *path,
                char ***dirs) {

        _cleanup_free_ char *chased = NULL;
        int r;

        assert(path);

        /* This adds [original_root]/path to dirs, if it exists. */

        r = chase(path, original_root, 0, &chased, NULL);
        if (r == -ENOENT) /* Ignore -ENOENT, after all most units won't have a drop-in dir. */
                return 0;
        if (r == -ENAMETOOLONG) {
                /* Also, ignore -ENAMETOOLONG but log about it. After all, users are not even able to create the
                 * drop-in dir in such case. This mostly happens for device units with an overly long /sys path. */
                log_debug_errno(r, "Path '%s' too long, couldn't canonicalize, ignoring.", path);
                return 0;
        }
        if (r < 0)
                return log_warning_errno(r, "Failed to canonicalize path '%s': %m", path);

        if (strv_consume(dirs, TAKE_PTR(chased)) < 0)
                return log_oom();

        return 0;
}

static int unit_file_find_dirs(
                const char *original_root,
                Set *unit_path_cache,
                const char *unit_path,
                const char *name,
                const char *suffix,
                char ***dirs) {

        _cleanup_free_ char *prefix = NULL, *instance = NULL, *built = NULL;
        bool is_instance, chopped;
        const char *dash;
        UnitType type;
        char *path;
        size_t n;
        int r;

        assert(unit_path);
        assert(name);
        assert(suffix);

        path = strjoina(unit_path, "/", name, suffix);
        if (!unit_path_cache || set_get(unit_path_cache, path)) {
                r = unit_file_add_dir(original_root, path, dirs);
                if (r < 0)
                        return r;
        }

        is_instance = unit_name_is_valid(name, UNIT_NAME_INSTANCE);
        if (is_instance) { /* Also try the template dir */
                _cleanup_free_ char *template = NULL;

                r = unit_name_template(name, &template);
                if (r < 0)
                        return log_error_errno(r, "Failed to generate template from unit name: %m");

                r = unit_file_find_dirs(original_root, unit_path_cache, unit_path, template, suffix, dirs);
                if (r < 0)
                        return r;
        }

        /* Return early for top level drop-ins. */
        if (unit_type_from_string(name) >= 0)
                return 0;

        /* Let's see if there's a "-" prefix for this unit name. If so, let's invoke ourselves for it. This will then
         * recursively do the same for all our prefixes. i.e. this means given "foo-bar-waldo.service" we'll also
         * search "foo-bar-.service" and "foo-.service".
         *
         * Note the order in which we do it: we traverse up adding drop-ins on each step. This means the more specific
         * drop-ins may override the more generic drop-ins, which is the intended behaviour. */

        r = unit_name_to_prefix(name, &prefix);
        if (r < 0)
                return log_error_errno(r, "Failed to derive unit name prefix from unit name: %m");

        chopped = false;
        for (;;) {
                dash = strrchr(prefix, '-');
                if (!dash) /* No dash? if so we are done */
                        return 0;

                n = (size_t) (dash - prefix);
                if (n == 0) /* Leading dash? If so, we are done */
                        return 0;

                if (prefix[n+1] != 0 || chopped) {
                        prefix[n+1] = 0;
                        break;
                }

                /* Trailing dash? If so, chop it off and try again, but not more than once. */
                prefix[n] = 0;
                chopped = true;
        }

        if (!unit_prefix_is_valid(prefix))
                return 0;

        type = unit_name_to_type(name);
        if (type < 0)
                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
                                       "Failed to derive unit type from unit name: %s",
                                       name);

        if (is_instance) {
                r = unit_name_to_instance(name, &instance);
                if (r < 0)
                        return log_error_errno(r, "Failed to derive unit name instance from unit name: %m");
        }

        r = unit_name_build_from_type(prefix, instance, type, &built);
        if (r < 0)
                return log_error_errno(r, "Failed to build prefix unit name: %m");

        return unit_file_find_dirs(original_root, unit_path_cache, unit_path, built, suffix, dirs);
}

int unit_file_find_dropin_paths(
                const char *original_root,
                char **lookup_path,
                Set *unit_path_cache,
                const char *dir_suffix,
                const char *file_suffix,
                const char *name,
                const Set *aliases,
                char ***ret) {

        _cleanup_strv_free_ char **dirs = NULL;
        const char *n;
        int r;

        assert(ret);

        if (name)
                STRV_FOREACH(p, lookup_path)
                        (void) unit_file_find_dirs(original_root, unit_path_cache, *p, name, dir_suffix, &dirs);

        SET_FOREACH(n, aliases)
                STRV_FOREACH(p, lookup_path)
                        (void) unit_file_find_dirs(original_root, unit_path_cache, *p, n, dir_suffix, &dirs);

        /* All the names in the unit are of the same type so just grab one. */
        n = name ?: (const char*) set_first(aliases);
        if (n) {
                UnitType type = _UNIT_TYPE_INVALID;

                type = unit_name_to_type(n);
                if (type < 0)
                        return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
                                               "Failed to derive unit type from unit name: %s", n);

                /* Special top level drop in for "<unit type>.<suffix>". Add this last as it's the most generic
                 * and should be able to be overridden by more specific drop-ins. */
                STRV_FOREACH(p, lookup_path)
                        (void) unit_file_find_dirs(original_root,
                                                   unit_path_cache,
                                                   *p,
                                                   unit_type_to_string(type),
                                                   dir_suffix,
                                                   &dirs);
        }

        if (strv_isempty(dirs)) {
                *ret = NULL;
                return 0;
        }

        r = conf_files_list_strv(ret, file_suffix, NULL, 0, (const char**) dirs);
        if (r < 0)
                return log_warning_errno(r, "Failed to create the list of configuration files: %m");

        return 1;
}