/* SPDX-License-Identifier: LGPL-2.1+ */

#include <errno.h>

#include <stdarg.h>

#include <stdio.h>

#include <stdlib.h>

#include "alloc-util.h"

#include "conf-files.h"

#include "dirent-util.h"

#include "dropin.h"

#include "escape.h"

#include "fd-util.h"

#include "fileio-label.h"

#include "fs-util.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 **_p, char **_q) {

        char prefix[DECIMAL_STR_MAX(unsigned)];

        _cleanup_free_ char *b = NULL;

        char *p, *q;

        assert(unit);

        assert(name);

        assert(_p);

        assert(_q);

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

        b = xescape(name, "/.");

        if (!b)

                return -ENOMEM;

        if (!filename_is_valid(b))

                return -EINVAL;

        p = strjoin(dir, "/", unit, ".d");

        if (!p)

                return -ENOMEM;

        q = strjoin(p, "/", prefix, "-", b, ".conf");

        if (!q) {

                free(p);

                return -ENOMEM;

        }

        *_p = p;

        *_q = 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_find_dir(

                const char *original_root,

                const char *path,

                char ***dirs) {

        _cleanup_free_ char *chased = NULL;

        int r;

        assert(path);

        r = chase_symlinks(path, original_root, 0, &chased);

        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);

        r = strv_push(dirs, chased);

        if (r < 0)

                return log_oom();

        chased = NULL;

        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_find_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;

        }

        /* 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 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,

                Set *names,

                char ***ret) {

        _cleanup_strv_free_ char **dirs = NULL;

        char *t, **p;

        Iterator i;

        int r;

        assert(ret);

        SET_FOREACH(t, names, i)

                STRV_FOREACH(p, lookup_path)

                        (void) unit_file_find_dirs(original_root, unit_path_cache, *p, t, 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;

}