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

#include <errno.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "alloc-util.h"

#include "fs-util.h"

#include "install.h"

#include "log.h"

#include "macro.h"

#include "mkdir.h"

#include "path-lookup.h"

#include "path-util.h"

#include "rm-rf.h"

#include "stat-util.h"

#include "string-util.h"

#include "strv.h"

#include "tmpfile-util.h"

#include "user-util.h"

#include "util.h"

int xdg_user_runtime_dir(char **ret, const char *suffix) {

        const char *e;

        char *j;

        assert(ret);

        assert(suffix);

        e = getenv("XDG_RUNTIME_DIR");

        if (!e)

                return -ENXIO;

        j = strappend(e, suffix);

        if (!j)

                return -ENOMEM;

        *ret = j;

        return 0;

}

int xdg_user_config_dir(char **ret, const char *suffix) {

        const char *e;

        char *j;

        int r;

        assert(ret);

        e = getenv("XDG_CONFIG_HOME");

        if (e)

                j = strappend(e, suffix);

        else {

                _cleanup_free_ char *home = NULL;

                r = get_home_dir(&home);

                if (r < 0)

                        return r;

                j = strjoin(home, "/.config", suffix);

        }

        if (!j)

                return -ENOMEM;

        *ret = j;

        return 0;

}

int xdg_user_data_dir(char **ret, const char *suffix) {

        const char *e;

        char *j;

        int r;

        assert(ret);

        assert(suffix);

        /* We don't treat /etc/xdg/systemd here as the spec

         * suggests because we assume that is a link to

         * /etc/systemd/ anyway. */

        e = getenv("XDG_DATA_HOME");

        if (e)

                j = strappend(e, suffix);

        else {

                _cleanup_free_ char *home = NULL;

                r = get_home_dir(&home);

                if (r < 0)

                        return r;

                j = strjoin(home, "/.local/share", suffix);

        }

        if (!j)

                return -ENOMEM;

        *ret = j;

        return 1;

}

static const char* const user_data_unit_paths[] = {

        "/usr/local/lib/systemd/user",

        "/usr/local/share/systemd/user",

        USER_DATA_UNIT_PATH,

        "/usr/lib/systemd/user",

        "/usr/share/systemd/user",

        NULL

};

static const char* const user_config_unit_paths[] = {

        USER_CONFIG_UNIT_PATH,

        "/etc/systemd/user",

        NULL

};

int xdg_user_dirs(char ***ret_config_dirs, char ***ret_data_dirs) {

        /* Implement the mechanisms defined in

         *

         * http://standards.freedesktop.org/basedir-spec/basedir-spec-0.6.html

         *

         * We look in both the config and the data dirs because we

         * want to encourage that distributors ship their unit files

         * as data, and allow overriding as configuration.

         */

        const char *e;

        _cleanup_strv_free_ char **config_dirs = NULL, **data_dirs = NULL;

        e = getenv("XDG_CONFIG_DIRS");

        if (e) {

                config_dirs = strv_split(e, ":");

                if (!config_dirs)

                        return -ENOMEM;

        }

        e = getenv("XDG_DATA_DIRS");

        if (e)

                data_dirs = strv_split(e, ":");

        else

                data_dirs = strv_new("/usr/local/share",

                                     "/usr/share");

        if (!data_dirs)

                return -ENOMEM;

        *ret_config_dirs = TAKE_PTR(config_dirs);

        *ret_data_dirs = TAKE_PTR(data_dirs);

        return 0;

}

static char** user_dirs(

                const char *persistent_config,

                const char *runtime_config,

                const char *global_persistent_config,

                const char *global_runtime_config,

                const char *generator,

                const char *generator_early,

                const char *generator_late,

                const char *transient,

                const char *persistent_control,

                const char *runtime_control) {

        _cleanup_strv_free_ char **config_dirs = NULL, **data_dirs = NULL;

        _cleanup_free_ char *data_home = NULL;

        _cleanup_strv_free_ char **res = NULL;

        int r;

        r = xdg_user_dirs(&config_dirs, &data_dirs);

        if (r < 0)

                return NULL;

        r = xdg_user_data_dir(&data_home, "/systemd/user");

        if (r < 0 && r != -ENXIO)

                return NULL;

        /* Now merge everything we found. */

        if (strv_extend(&res, persistent_control) < 0)

                return NULL;

        if (strv_extend(&res, runtime_control) < 0)

                return NULL;

        if (strv_extend(&res, transient) < 0)

                return NULL;

        if (strv_extend(&res, generator_early) < 0)

                return NULL;

        if (strv_extend_strv_concat(&res, config_dirs, "/systemd/user") < 0)

                return NULL;

        if (strv_extend(&res, persistent_config) < 0)

                return NULL;

        /* global config has lower priority than the user config of the same type */

        if (strv_extend(&res, global_persistent_config) < 0)

                return NULL;

        if (strv_extend_strv(&res, (char**) user_config_unit_paths, false) < 0)

                return NULL;

        if (strv_extend(&res, runtime_config) < 0)

                return NULL;

        if (strv_extend(&res, global_runtime_config) < 0)

                return NULL;

        if (strv_extend(&res, generator) < 0)

                return NULL;

        if (strv_extend(&res, data_home) < 0)

                return NULL;

        if (strv_extend_strv_concat(&res, data_dirs, "/systemd/user") < 0)

                return NULL;

        if (strv_extend_strv(&res, (char**) user_data_unit_paths, false) < 0)

                return NULL;

        if (strv_extend(&res, generator_late) < 0)

                return NULL;

        if (path_strv_make_absolute_cwd(res) < 0)

                return NULL;

        return TAKE_PTR(res);

}

bool path_is_user_data_dir(const char *path) {

        assert(path);

        return strv_contains((char**) user_data_unit_paths, path);

}

bool path_is_user_config_dir(const char *path) {

        assert(path);

        return strv_contains((char**) user_config_unit_paths, path);

}

static int acquire_generator_dirs(

                UnitFileScope scope,

                const char *tempdir,

                char **generator,

                char **generator_early,

                char **generator_late) {

        _cleanup_free_ char *x = NULL, *y = NULL, *z = NULL;

        const char *prefix;

        assert(generator);

        assert(generator_early);

        assert(generator_late);

        assert(IN_SET(scope, UNIT_FILE_SYSTEM, UNIT_FILE_USER, UNIT_FILE_GLOBAL));

        if (scope == UNIT_FILE_GLOBAL)

                return -EOPNOTSUPP;

        if (tempdir)

                prefix = tempdir;

        else if (scope == UNIT_FILE_SYSTEM)

                prefix = "/run/systemd";

        else {

                /* UNIT_FILE_USER */

                const char *e;

                e = getenv("XDG_RUNTIME_DIR");

                if (!e)

                        return -ENXIO;

                prefix = strjoina(e, "/systemd");

        }

        x = strappend(prefix, "/generator");

        if (!x)

                return -ENOMEM;

        y = strappend(prefix, "/generator.early");

        if (!y)

                return -ENOMEM;

        z = strappend(prefix, "/generator.late");

        if (!z)

                return -ENOMEM;

        *generator = TAKE_PTR(x);

        *generator_early = TAKE_PTR(y);

        *generator_late = TAKE_PTR(z);

        return 0;

}

static int acquire_transient_dir(

                UnitFileScope scope,

                const char *tempdir,

                char **ret) {

        char *transient;

        assert(ret);

        assert(IN_SET(scope, UNIT_FILE_SYSTEM, UNIT_FILE_USER, UNIT_FILE_GLOBAL));

        if (scope == UNIT_FILE_GLOBAL)

                return -EOPNOTSUPP;

        if (tempdir)

                transient = strjoin(tempdir, "/transient");

        else if (scope == UNIT_FILE_SYSTEM)

                transient = strdup("/run/systemd/transient");

        else

                return xdg_user_runtime_dir(ret, "/systemd/transient");

        if (!transient)

                return -ENOMEM;

        *ret = transient;

        return 0;

}

static int acquire_config_dirs(UnitFileScope scope, char **persistent, char **runtime) {

        _cleanup_free_ char *a = NULL, *b = NULL;

        int r;

        assert(persistent);

        assert(runtime);

        switch (scope) {

        case UNIT_FILE_SYSTEM:

                a = strdup(SYSTEM_CONFIG_UNIT_PATH);

                b = strdup("/run/systemd/system");

                break;

        case UNIT_FILE_GLOBAL:

                a = strdup(USER_CONFIG_UNIT_PATH);

                b = strdup("/run/systemd/user");

                break;

        case UNIT_FILE_USER:

                r = xdg_user_config_dir(&a, "/systemd/user");

                if (r < 0 && r != -ENXIO)

                        return r;

                r = xdg_user_runtime_dir(runtime, "/systemd/user");

                if (r < 0) {

                        if (r != -ENXIO)

                                return r;

                        /* If XDG_RUNTIME_DIR is not set, don't consider that fatal, simply initialize the runtime

                         * directory to NULL */

                        *runtime = NULL;

                }

                *persistent = TAKE_PTR(a);

                return 0;

        default:

                assert_not_reached("Hmm, unexpected scope value.");

        }

        if (!a || !b)

                return -ENOMEM;

        *persistent = TAKE_PTR(a);

        *runtime = TAKE_PTR(b);

        return 0;

}

static int acquire_control_dirs(UnitFileScope scope, char **persistent, char **runtime) {

        _cleanup_free_ char *a = NULL;

        int r;

        assert(persistent);

        assert(runtime);

        switch (scope) {

        case UNIT_FILE_SYSTEM:  {

                _cleanup_free_ char *b = NULL;

                a = strdup("/etc/systemd/system.control");

                if (!a)

                        return -ENOMEM;

                b = strdup("/run/systemd/system.control");

                if (!b)

                        return -ENOMEM;

                *runtime = TAKE_PTR(b);

                break;

        }

        case UNIT_FILE_USER:

                r = xdg_user_config_dir(&a, "/systemd/user.control");

                if (r < 0 && r != -ENXIO)

                        return r;

                r = xdg_user_runtime_dir(runtime, "/systemd/user.control");

                if (r < 0) {

                        if (r != -ENXIO)

                                return r;

                        /* If XDG_RUNTIME_DIR is not set, don't consider this fatal, simply initialize the directory to

                         * NULL */

                        *runtime = NULL;

                }

                break;

        case UNIT_FILE_GLOBAL:

                return -EOPNOTSUPP;

        default:

                assert_not_reached("Hmm, unexpected scope value.");

        }

        *persistent = TAKE_PTR(a);

        return 0;

}

static int acquire_attached_dirs(

                UnitFileScope scope,

                char **ret_persistent,

                char **ret_runtime) {

        _cleanup_free_ char *a = NULL, *b = NULL;

        assert(ret_persistent);

        assert(ret_runtime);

        /* Portable services are not available to regular users for now. */

        if (scope != UNIT_FILE_SYSTEM)

                return -EOPNOTSUPP;

        a = strdup("/etc/systemd/system.attached");

        if (!a)

                return -ENOMEM;

        b = strdup("/run/systemd/system.attached");

        if (!b)

                return -ENOMEM;

        *ret_persistent = TAKE_PTR(a);

        *ret_runtime = TAKE_PTR(b);

        return 0;

}

static int patch_root_prefix(char **p, const char *root_dir) {

        char *c;

        assert(p);

        if (!*p)

                return 0;

        c = prefix_root(root_dir, *p);

        if (!c)

                return -ENOMEM;

        free(*p);

        *p = c;

        return 0;

}

static int patch_root_prefix_strv(char **l, const char *root_dir) {

        char **i;

        int r;

        if (!root_dir)

                return 0;

        STRV_FOREACH(i, l) {

                r = patch_root_prefix(i, root_dir);

                if (r < 0)

                        return r;

        }

        return 0;

}

int lookup_paths_init(

                LookupPaths *p,

                UnitFileScope scope,

                LookupPathsFlags flags,

                const char *root_dir) {

        _cleanup_(rmdir_and_freep) char *tempdir = NULL;

        _cleanup_free_ char

                *root = NULL,

                *persistent_config = NULL, *runtime_config = NULL,

                *global_persistent_config = NULL, *global_runtime_config = NULL,

                *generator = NULL, *generator_early = NULL, *generator_late = NULL,

                *transient = NULL,

                *persistent_control = NULL, *runtime_control = NULL,

                *persistent_attached = NULL, *runtime_attached = NULL;

        bool append = false; /* Add items from SYSTEMD_UNIT_PATH before normal directories */

        _cleanup_strv_free_ char **paths = NULL;

        const char *e;

        int r;

        assert(p);

        assert(scope >= 0);

        assert(scope < _UNIT_FILE_SCOPE_MAX);

#if HAVE_SPLIT_USR

        flags |= LOOKUP_PATHS_SPLIT_USR;

#endif

        if (!empty_or_root(root_dir)) {

                if (scope == UNIT_FILE_USER)

                        return -EINVAL;

                r = is_dir(root_dir, true);

                if (r < 0)

                        return r;

                if (r == 0)

                        return -ENOTDIR;

                root = strdup(root_dir);

                if (!root)

                        return -ENOMEM;

        }

        if (flags & LOOKUP_PATHS_TEMPORARY_GENERATED) {

                r = mkdtemp_malloc("/tmp/systemd-temporary-XXXXXX", &tempdir);

                if (r < 0)

                        return log_debug_errno(r, "Failed to create temporary directory: %m");

        }

        /* Note: when XDG_RUNTIME_DIR is not set this will not return -ENXIO, but simply set runtime_config to NULL */

        r = acquire_config_dirs(scope, &persistent_config, &runtime_config);

        if (r < 0)

                return r;

        if (scope == UNIT_FILE_USER) {

                r = acquire_config_dirs(UNIT_FILE_GLOBAL, &global_persistent_config, &global_runtime_config);

                if (r < 0)

                        return r;

        }

        if ((flags & LOOKUP_PATHS_EXCLUDE_GENERATED) == 0) {

                /* Note: if XDG_RUNTIME_DIR is not set, this will fail completely with ENXIO */

                r = acquire_generator_dirs(scope, tempdir,

                                           &generator, &generator_early, &generator_late);

                if (r < 0 && !IN_SET(r, -EOPNOTSUPP, -ENXIO))

                        return r;

        }

        /* Note: if XDG_RUNTIME_DIR is not set, this will fail completely with ENXIO */

        r = acquire_transient_dir(scope, tempdir, &transient);

        if (r < 0 && !IN_SET(r, -EOPNOTSUPP, -ENXIO))

                return r;

        /* Note: when XDG_RUNTIME_DIR is not set this will not return -ENXIO, but simply set runtime_control to NULL */

        r = acquire_control_dirs(scope, &persistent_control, &runtime_control);

        if (r < 0 && r != -EOPNOTSUPP)

                return r;

        r = acquire_attached_dirs(scope, &persistent_attached, &runtime_attached);

        if (r < 0 && r != -EOPNOTSUPP)

                return r;

        /* First priority is whatever has been passed to us via env vars */

        e = getenv("SYSTEMD_UNIT_PATH");

        if (e) {

                const char *k;

                k = endswith(e, ":");

                if (k) {

                        e = strndupa(e, k - e);

                        append = true;

                }

                /* FIXME: empty components in other places should be rejected. */

                r = path_split_and_make_absolute(e, &paths);

                if (r < 0)

                        return r;

        }

        if (!paths || append) {

                /* Let's figure something out. */

                _cleanup_strv_free_ char **add = NULL;

                /* For the user units we include share/ in the search

                 * path in order to comply with the XDG basedir spec.

                 * For the system stuff we avoid such nonsense. OTOH

                 * we include /lib in the search path for the system

                 * stuff but avoid it for user stuff. */

                switch (scope) {

                case UNIT_FILE_SYSTEM:

                        add = strv_new(

                                        /* If you modify this you also want to modify

                                         * systemdsystemunitpath= in systemd.pc.in! */

                                        STRV_IFNOTNULL(persistent_control),

                                        STRV_IFNOTNULL(runtime_control),

                                        STRV_IFNOTNULL(transient),

                                        STRV_IFNOTNULL(generator_early),

                                        persistent_config,

                                        SYSTEM_CONFIG_UNIT_PATH,

                                        "/etc/systemd/system",

                                        STRV_IFNOTNULL(persistent_attached),

                                        runtime_config,

                                        "/run/systemd/system",

                                        STRV_IFNOTNULL(runtime_attached),

                                        STRV_IFNOTNULL(generator),

                                        "/usr/local/lib/systemd/system",

                                        SYSTEM_DATA_UNIT_PATH,

                                        "/usr/lib/systemd/system",

                                        STRV_IFNOTNULL(flags & LOOKUP_PATHS_SPLIT_USR ? "/lib/systemd/system" : NULL),

                                        STRV_IFNOTNULL(generator_late));

                        break;

                case UNIT_FILE_GLOBAL:

                        add = strv_new(

                                        /* If you modify this you also want to modify

                                         * systemduserunitpath= in systemd.pc.in, and

                                         * the arrays in user_dirs() above! */

                                        STRV_IFNOTNULL(persistent_control),

                                        STRV_IFNOTNULL(runtime_control),

                                        STRV_IFNOTNULL(transient),

                                        STRV_IFNOTNULL(generator_early),

                                        persistent_config,

                                        USER_CONFIG_UNIT_PATH,

                                        "/etc/systemd/user",

                                        runtime_config,

                                        "/run/systemd/user",

                                        STRV_IFNOTNULL(generator),

                                        "/usr/local/share/systemd/user",

                                        "/usr/share/systemd/user",

                                        "/usr/local/lib/systemd/user",

                                        USER_DATA_UNIT_PATH,

                                        "/usr/lib/systemd/user",

                                        STRV_IFNOTNULL(generator_late));

                        break;

                case UNIT_FILE_USER:

                        add = user_dirs(persistent_config, runtime_config,

                                        global_persistent_config, global_runtime_config,

                                        generator, generator_early, generator_late,

                                        transient,

                                        persistent_control, runtime_control);

                        break;

                default:

                        assert_not_reached("Hmm, unexpected scope?");

                }

                if (!add)

                        return -ENOMEM;

                if (paths) {

                        r = strv_extend_strv(&paths, add, true);

                        if (r < 0)

                                return r;

                } else

                        /* Small optimization: if paths is NULL (and it usually is), we can simply assign 'add' to it,

                         * and don't have to copy anything */

                        paths = TAKE_PTR(add);

        }

        r = patch_root_prefix(&persistent_config, root);

        if (r < 0)

                return r;

        r = patch_root_prefix(&runtime_config, root);

        if (r < 0)

                return r;

        r = patch_root_prefix(&generator, root);

        if (r < 0)

                return r;

        r = patch_root_prefix(&generator_early, root);

        if (r < 0)

                return r;

        r = patch_root_prefix(&generator_late, root);

        if (r < 0)

                return r;

        r = patch_root_prefix(&transient, root);

        if (r < 0)

                return r;

        r = patch_root_prefix(&persistent_control, root);

        if (r < 0)

                return r;

        r = patch_root_prefix(&runtime_control, root);

        if (r < 0)

                return r;

        r = patch_root_prefix(&persistent_attached, root);

        if (r < 0)

                return r;

        r = patch_root_prefix(&runtime_attached, root);

        if (r < 0)

                return r;

        r = patch_root_prefix_strv(paths, root);

        if (r < 0)

                return -ENOMEM;

        *p = (LookupPaths) {

                .search_path = strv_uniq(paths),

                .persistent_config = TAKE_PTR(persistent_config),

                .runtime_config = TAKE_PTR(runtime_config),

                .generator = TAKE_PTR(generator),

                .generator_early = TAKE_PTR(generator_early),

                .generator_late = TAKE_PTR(generator_late),

                .transient = TAKE_PTR(transient),

                .persistent_control = TAKE_PTR(persistent_control),

                .runtime_control = TAKE_PTR(runtime_control),

                .persistent_attached = TAKE_PTR(persistent_attached),

                .runtime_attached = TAKE_PTR(runtime_attached),

                .root_dir = TAKE_PTR(root),

                .temporary_dir = TAKE_PTR(tempdir),

        };

        paths = NULL;

        return 0;

}

void lookup_paths_free(LookupPaths *p) {

        if (!p)

                return;

        p->search_path = strv_free(p->search_path);

        p->persistent_config = mfree(p->persistent_config);

        p->runtime_config = mfree(p->runtime_config);

        p->persistent_attached = mfree(p->persistent_attached);

        p->runtime_attached = mfree(p->runtime_attached);

        p->generator = mfree(p->generator);

        p->generator_early = mfree(p->generator_early);

        p->generator_late = mfree(p->generator_late);

        p->transient = mfree(p->transient);

        p->persistent_control = mfree(p->persistent_control);

        p->runtime_control = mfree(p->runtime_control);

        p->root_dir = mfree(p->root_dir);

        p->temporary_dir = mfree(p->temporary_dir);

}

int lookup_paths_reduce(LookupPaths *p) {

        _cleanup_free_ struct stat *stats = NULL;

        size_t n_stats = 0, allocated = 0;

        size_t c = 0;

        int r;

        assert(p);

        /* Drop duplicates and non-existing directories from the search path. We figure out whether two directories are

         * the same by comparing their device and inode numbers. */

        if (!p->search_path)

                return 0;

        while (p->search_path[c]) {

                struct stat st;

                size_t k;

                /* Never strip the transient and control directories from the path */

                if (path_equal_ptr(p->search_path[c], p->transient) ||

                    path_equal_ptr(p->search_path[c], p->persistent_control) ||

                    path_equal_ptr(p->search_path[c], p->runtime_control)) {

                        c++;

                        continue;

                }

                r = chase_symlinks_and_stat(p->search_path[c], p->root_dir, 0, NULL, &st);

                if (r == -ENOENT)

                        goto remove_item;

                if (r < 0) {

                        /* If something we don't grok happened, let's better leave it in. */

                        log_debug_errno(r, "Failed to chase and stat %s: %m", p->search_path[c]);

                        c++;

                        continue;

                }

                for (k = 0; k < n_stats; k++)

                        if (stats[k].st_dev == st.st_dev &&

                            stats[k].st_ino == st.st_ino)

                                break;

                if (k < n_stats) /* Is there already an entry with the same device/inode? */

                        goto remove_item;

                if (!GREEDY_REALLOC(stats, allocated, n_stats+1))

                        return -ENOMEM;

                stats[n_stats++] = st;

                c++;

                continue;

        remove_item:

                free(p->search_path[c]);

                memmove(p->search_path + c,

                        p->search_path + c + 1,

                        (strv_length(p->search_path + c + 1) + 1) * sizeof(char*));

        }

        if (strv_isempty(p->search_path)) {

                log_debug("Ignoring unit files.");

                p->search_path = strv_free(p->search_path);

        } else {

                _cleanup_free_ char *t;

                t = strv_join(p->search_path, "\n\t");

                if (!t)

                        return -ENOMEM;

                log_debug("Looking for unit files in (higher priority first):\n\t%s", t);

        }

        return 0;

}

int lookup_paths_mkdir_generator(LookupPaths *p) {

        int r, q;

        assert(p);

        if (!p->generator || !p->generator_early || !p->generator_late)

                return -EINVAL;

        r = mkdir_p_label(p->generator, 0755);

        q = mkdir_p_label(p->generator_early, 0755);

        if (q < 0 && r >= 0)