install: add systemd-install tool for managing alias/wants symlinks

1 files changed, 593 insertions, 0 deletions

diff --git a/src/install.c b/src/install.c
new file mode 100644
index 0000000000..e3db63769f
--- /dev/null
+++ b/src/install.c
@@ -0,0 +1,593 @@
+/*-*- Mode: C; c-basic-offset: 8 -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2010 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <sys/stat.h>
+#include <stdio.h>
+#include <getopt.h>
+#include <errno.h>
+#include <unistd.h>
+
+#include "log.h"
+#include "path-lookup.h"
+#include "util.h"
+#include "macro.h"
+#include "strv.h"
+#include "conf-parser.h"
+
+static bool arg_force = false;
+
+static enum {
+        WHERE_SYSTEM,
+        WHERE_SESSION,
+        WHERE_GLOBAL,
+} arg_where = WHERE_SYSTEM;
+
+static enum {
+        ACTION_INVALID,
+        ACTION_ENABLE,
+        ACTION_DISABLE,
+        ACTION_TEST
+} arg_action = ACTION_INVALID;
+
+typedef struct {
+        char *name;
+        char *path;
+
+        char **aliases;
+        char **wanted_by;
+} InstallInfo;
+
+Hashmap *will_install = NULL, *have_installed = NULL;
+
+static int help(void) {
+
+        printf("%s [options]\n\n"
+               "  -h --help        Show this help\n"
+               "     --force       Override existing links\n"
+               "     --system      Install into system\n"
+               "     --session     Install into session\n"
+               "     --global      Install into all sessions\n"
+               "Commands:\n"
+               "  enable [NAME...]    Enable one or more units\n"
+               "  disable [NAME...]   Disable one or more units\n"
+               "  test [NAME...]      Test whether any of the specified units are enabled\n",
+               __progname);
+
+        return 0;
+}
+
+static int parse_argv(int argc, char *argv[]) {
+
+        enum {
+                ARG_SESSION = 0x100,
+                ARG_SYSTEM,
+                ARG_GLOBAL,
+                ARG_FORCE
+        };
+
+        static const struct option options[] = {
+                { "help",      no_argument,       NULL, 'h'         },
+                { "session",   no_argument,       NULL, ARG_SESSION },
+                { "system",    no_argument,       NULL, ARG_SYSTEM  },
+                { "global",    no_argument,       NULL, ARG_GLOBAL  },
+                { "force",     no_argument,       NULL, ARG_FORCE   },
+                { NULL,        0,                 NULL, 0           }
+        };
+
+        int c;
+
+        assert(argc >= 1);
+        assert(argv);
+
+        while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0) {
+
+                switch (c) {
+
+                case 'h':
+                        help();
+                        return 0;
+
+                case ARG_SESSION:
+                        arg_where = WHERE_SESSION;
+                        break;
+
+                case ARG_SYSTEM:
+                        arg_where = WHERE_SYSTEM;
+                        break;
+
+                case ARG_GLOBAL:
+                        arg_where = WHERE_GLOBAL;
+                        break;
+
+                case ARG_FORCE:
+                        arg_force = true;
+                        break;
+
+                case '?':
+                        return -EINVAL;
+
+                default:
+                        log_error("Unknown option code %c", c);
+                        return -EINVAL;
+                }
+        }
+
+        if (optind >= argc) {
+                log_error("Missing verb.");
+                return -EINVAL;
+        }
+
+        if (streq(argv[optind], "enable"))
+                arg_action = ACTION_ENABLE;
+        else if (streq(argv[optind], "disable"))
+                arg_action = ACTION_DISABLE;
+        else if (streq(argv[optind], "test"))
+                arg_action = ACTION_TEST;
+        else {
+                log_error("Unknown verb %s", argv[optind]);
+                return -EINVAL;
+        }
+
+        optind++;
+
+        if (optind >= argc) {
+                log_error("Missing unit name.");
+                return -EINVAL;
+        }
+
+        return 1;
+}
+
+static void install_info_free(InstallInfo *i) {
+        assert(i);
+
+        free(i->name);
+        free(i->path);
+        strv_free(i->aliases);
+        strv_free(i->wanted_by);
+        free(i);
+}
+
+static void install_info_hashmap_free(Hashmap *m) {
+        InstallInfo *i;
+
+        while ((i = hashmap_steal_first(m)))
+                install_info_free(i);
+
+        hashmap_free(m);
+}
+
+static bool unit_name_valid(const char *name) {
+
+        /* This is a minimal version of unit_name_valid() from
+         * unit-name.c */
+
+        if (strchr(name, '/'))
+                return false;
+
+        if (!*name)
+                return false;
+
+        if (ignore_file(name))
+                return false;
+
+        return true;
+}
+
+static int install_info_add(const char *name) {
+        InstallInfo *i;
+        int r;
+
+        if (!unit_name_valid(name))
+                return -EINVAL;
+
+        if (hashmap_get(have_installed, name) ||
+            hashmap_get(will_install, name))
+                return 0;
+
+        if (!(i = new0(InstallInfo, 1))) {
+                r = -ENOMEM;
+                goto fail;
+        }
+
+        if (!(i->name = strdup(name))) {
+                r = -ENOMEM;
+                goto fail;
+        }
+
+        if ((r = hashmap_put(will_install, i->name, i)) < 0)
+                goto fail;
+
+        return 0;
+
+fail:
+        if (i)
+                install_info_free(i);
+
+        return r;
+}
+
+static int config_parse_also(
+                const char *filename,
+                unsigned line,
+                const char *section,
+                const char *lvalue,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        char *w;
+        size_t l;
+        char *state;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+
+        FOREACH_WORD_QUOTED(w, l, rvalue, state) {
+                char *n;
+                int r;
+
+                if (!(n = strndup(w, l)))
+                        return -ENOMEM;
+
+                r = install_info_add(n);
+                free(n);
+
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+static int create_symlink(const char *old_path, const char *new_path) {
+        int r;
+
+        assert(old_path);
+        assert(new_path);
+
+        if (arg_action == ACTION_ENABLE) {
+                char *dest;
+
+                mkdir_parents(new_path, 0755);
+
+                if (symlink(old_path, new_path) >= 0)
+                        return 0;
+
+                if (errno != EEXIST) {
+                        log_error("Cannot link %s to %s: %m", old_path, new_path);
+                        return -errno;
+                }
+
+                if ((r = readlink_and_make_absolute(new_path, &dest)) < 0) {
+
+                        if (errno == EINVAL) {
+                                log_error("Cannot link %s to %s, file exists already and is not a symlink.", old_path, new_path);
+                                return -EEXIST;
+                        }
+
+                        log_error("readlink() failed: %s", strerror(-r));
+                        return r;
+                }
+
+                if (streq(dest, old_path)) {
+                        free(dest);
+                        return 0;
+                }
+
+                if (!arg_force) {
+                        log_error("Cannot link %s to %s, symlink exists already and points to %s.", old_path, new_path, dest);
+                        free(dest);
+                        return -EEXIST;
+                }
+
+                free(dest);
+                unlink(new_path);
+
+                if (symlink(old_path, new_path) >= 0)
+                        return 0;
+
+                log_error("Cannot link %s to %s: %m", old_path, new_path);
+                return -errno;
+
+        } else if (arg_action == ACTION_DISABLE) {
+                char *dest;
+
+                if ((r = readlink_and_make_absolute(new_path, &dest)) < 0) {
+                        if (errno == ENOENT)
+                                return 0;
+
+                        if (errno == EINVAL) {
+                                log_warning("File %s not a symlink, ignoring.", old_path);
+                                return 0;
+                        }
+
+                        log_error("readlink() failed: %s", strerror(-r));
+                        return r;
+                }
+
+                if (!streq(dest, old_path)) {
+                        log_warning("File %s not a symlink to %s but points to %s, ignoring.", new_path, old_path, dest);
+                        free(dest);
+                        return 0;
+                }
+
+                free(dest);
+                if (unlink(new_path) >= 0)
+                        return 0;
+
+                log_error("Cannot unlink %s: %m", new_path);
+                return -errno;
+
+        } else if (arg_action == ACTION_TEST) {
+                char *dest;
+
+                if ((r = readlink_and_make_absolute(new_path, &dest)) < 0) {
+
+                        if (errno == ENOENT || errno == EINVAL)
+                                return 0;
+
+                        log_error("readlink() failed: %s", strerror(-r));
+                        return r;
+                }
+
+                if (streq(dest, old_path)) {
+                        free(dest);
+                        return 1;
+                }
+
+                return 0;
+        }
+
+        assert_not_reached("Unknown action.");
+}
+
+static int install_info_symlink_alias(InstallInfo *i, const char *config_path) {
+        char **s;
+        char *alias_path = NULL;
+        int r;
+
+        assert(i);
+
+        STRV_FOREACH(s, i->aliases) {
+
+                if (!unit_name_valid(*s)) {
+                        log_error("Invalid name %s.", *s);
+                        r = -EINVAL;
+                        goto finish;
+                }
+
+                free(alias_path);
+                if (!(alias_path = path_make_absolute(*s, config_path))) {
+                        log_error("Out of memory");
+                        r = -ENOMEM;
+                        goto finish;
+                }
+
+                if ((r = create_symlink(i->path, alias_path)) != 0)
+                        goto finish;
+        }
+
+        r = 0;
+
+finish:
+        free(alias_path);
+
+        return r;
+}
+
+static int install_info_symlink_wants(InstallInfo *i, const char *config_path) {
+        char **s;
+        char *alias_path = NULL;
+        int r;
+
+        assert(i);
+
+        STRV_FOREACH(s, i->wanted_by) {
+                if (!unit_name_valid(*s)) {
+                        log_error("Invalid name %s.", *s);
+                        r = -EINVAL;
+                        goto finish;
+                }
+
+                free(alias_path);
+                alias_path = NULL;
+
+                if (asprintf(&alias_path, "%s/%s.wants/%s", config_path, *s, i->name) < 0) {
+                        log_error("Out of memory");
+                        r = -ENOMEM;
+                        goto finish;
+                }
+
+                if ((r = create_symlink(i->path, alias_path)) != 0)
+                        goto finish;
+
+                if (arg_action == ACTION_DISABLE) {
+                        char *t;
+
+                        /* Try to remove .wants dir if we don't need it anymore */
+                        if (asprintf(&t, "%s/%s.wants", config_path, *s) >= 0) {
+                                rmdir(t);
+                                free(t);
+                        }
+                }
+        }
+
+        r = 0;
+
+finish:
+        free(alias_path);
+
+        return r;
+}
+
+static int install_info_apply(LookupPaths *paths, InstallInfo *i, const char *config_path) {
+
+        const ConfigItem items[] = {
+                { "Alias",    config_parse_strv, &i->aliases,   "Install" },
+                { "WantedBy", config_parse_strv, &i->wanted_by, "Install" },
+                { "Also",     config_parse_also, NULL,          "Install" },
+
+                { NULL, NULL, NULL, NULL }
+        };
+
+        char **p;
+        char *filename = NULL;
+        FILE *f = NULL;
+        int r;
+
+        assert(paths);
+        assert(i);
+
+        STRV_FOREACH(p, paths->unit_path) {
+
+                if (!(filename = path_make_absolute(i->name, *p))) {
+                        log_error("Out of memory");
+                        return -ENOMEM;
+                }
+
+                if ((f = fopen(filename, "re")))
+                        break;
+
+                free(filename);
+                filename = NULL;
+
+                if (errno != ENOENT) {
+                        log_error("Failed to open %s: %m", filename);
+                        return -errno;
+                }
+        }
+
+        if (!f) {
+                log_error("Couldn't find %s.", i->name);
+                return -ENOENT;
+        }
+
+        i->path = filename;
+
+        if ((r = config_parse(filename, f, NULL, items, true, i)) < 0) {
+                fclose(f);
+                return r;
+        }
+
+        fclose(f);
+
+        if ((r = install_info_symlink_alias(i, config_path)) != 0)
+                return r;
+
+        if ((r = install_info_symlink_wants(i, config_path)) != 0)
+                return r;
+
+        return 0;
+}
+
+static char *get_config_path(void) {
+
+        switch (arg_where) {
+
+        case WHERE_SYSTEM:
+                return strdup(SYSTEM_CONFIG_UNIT_PATH);
+
+        case WHERE_GLOBAL:
+                return strdup(SESSION_CONFIG_UNIT_PATH);
+
+        case WHERE_SESSION: {
+                char *p;
+
+                if (session_config_home(&p) < 0)
+                        return NULL;
+
+                return p;
+        }
+
+        default:
+                assert_not_reached("Unknown config path.");
+        }
+}
+
+int main(int argc, char *argv[]) {
+        int r, retval = 1, j;
+        LookupPaths paths;
+        InstallInfo *i;
+        char *config_path = NULL;
+
+        zero(paths);
+
+        log_set_target(LOG_TARGET_CONSOLE);
+        log_set_max_level(LOG_INFO);
+        log_parse_environment();
+
+        if ((r = parse_argv(argc, argv)) < 0)
+                goto finish;
+        else if (r == 0) {
+                retval = 0;
+                goto finish;
+        }
+
+        if ((r = lookup_paths_init(&paths, arg_where == WHERE_SYSTEM ? MANAGER_INIT : MANAGER_SESSION)) < 0) {
+                log_error("Failed to determine lookup paths: %s", strerror(-r));
+                goto finish;
+        }
+
+        if (!(config_path = get_config_path())) {
+                log_error("Failed to determine config path");
+                goto finish;
+        }
+
+        will_install = hashmap_new(string_hash_func, string_compare_func);
+        have_installed = hashmap_new(string_hash_func, string_compare_func);
+
+        if (!will_install || !have_installed) {
+                log_error("Failed to allocate unit sets.");
+                goto finish;
+        }
+
+        for (j = optind; j < argc; j++)
+                if ((r = install_info_add(argv[j])) < 0)
+                        goto finish;
+
+        while ((i = hashmap_first(will_install))) {
+                assert_se(hashmap_move_one(have_installed, will_install, i->name) == 0);
+
+                if ((r = install_info_apply(&paths, i, config_path)) != 0) {
+
+                        if (r < 0)
+                                goto finish;
+
+                        /* In test mode and found something */
+                        retval = 0;
+                        goto finish;
+                }
+        }
+
+        retval = arg_action == ACTION_TEST ? 1 : 0;
+
+finish:
+        install_info_hashmap_free(will_install);
+        install_info_hashmap_free(have_installed);
+
+        lookup_paths_free(&paths);
+
+        free(config_path);
+
+        return retval;
+}