79413b673b
Previously, the %u, %U, %s and %h specifiers would resolve to the user name, numeric user ID, shell and home directory of the user configured in the User= setting of a unit file, or the user of the manager instance if no User= setting was configured. That at least was the theory. In real-life this was not ever actually useful: - For the systemd --user instance it made no sense to ever set User=, since the instance runs in user context after all, and hence the privileges to change user IDs don't even exist. The four specifiers were actually not useful at all in this case. - For the systemd --system instance we did not allow any resolving that would require NSS. Hence, %s and %h were not supported, unless User=root was set, in which case they would be hardcoded to /bin/sh and /root, to avoid NSS. Then, %u would actually resolve to whatever was set with User=, but %U would only resolve to the numeric UID of that setting if the User= was specified in numeric form, or happened to be root (in which case 0 was hardcoded as mapping). Two of the specifiers are entirely useless in this case, one is realistically also useless, and one is pretty pointless. - Resolving of these settings would only happen if User= was actually set *before* the specifiers where resolved. This behaviour was undocumented and is really ugly, as specifiers should actually be considered something that applies to the whole file equally, independently of order... With this change, %u, %U, %s and %h are drastically simplified: they now always refer to the user that is running the service instance, and the user configured in the unit file is irrelevant. For the system instance of systemd this means they always resolve to "root", "0", "/bin/sh" and "/root", thus avoiding NSS. For the user instance, to the data for the specific user. The new behaviour is identical to the old behaviour in all --user cases and for all units that have no User= set (or set to "0" or "root").
133 lines
4 KiB
C
133 lines
4 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2013 Zbigniew Jędrzejewski-Szmek
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <stdlib.h>
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#include "alloc-util.h"
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#include "formats-util.h"
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#include "install-printf.h"
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#include "specifier.h"
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#include "unit-name.h"
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#include "user-util.h"
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#include "util.h"
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static int specifier_prefix_and_instance(char specifier, void *data, void *userdata, char **ret) {
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UnitFileInstallInfo *i = userdata;
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assert(i);
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return unit_name_to_prefix_and_instance(i->name, ret);
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}
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static int specifier_prefix(char specifier, void *data, void *userdata, char **ret) {
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UnitFileInstallInfo *i = userdata;
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assert(i);
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return unit_name_to_prefix(i->name, ret);
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}
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static int specifier_instance(char specifier, void *data, void *userdata, char **ret) {
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UnitFileInstallInfo *i = userdata;
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char *instance;
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int r;
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assert(i);
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r = unit_name_to_instance(i->name, &instance);
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if (r < 0)
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return r;
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if (!instance) {
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instance = strdup("");
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if (!instance)
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return -ENOMEM;
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}
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*ret = instance;
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return 0;
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}
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static int specifier_user_name(char specifier, void *data, void *userdata, char **ret) {
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char *t;
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/* If we are UID 0 (root), this will not result in NSS,
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* otherwise it might. This is good, as we want to be able to
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* run this in PID 1, where our user ID is 0, but where NSS
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* lookups are not allowed. */
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t = getusername_malloc();
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if (!t)
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return -ENOMEM;
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*ret = t;
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return 0;
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}
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static int specifier_user_id(char specifier, void *data, void *userdata, char **ret) {
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if (asprintf(ret, UID_FMT, getuid()) < 0)
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return -ENOMEM;
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return 0;
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}
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int install_full_printf(UnitFileInstallInfo *i, const char *format, char **ret) {
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/* This is similar to unit_full_printf() but does not support
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* anything path-related.
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*
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* %n: the full id of the unit (foo@bar.waldo)
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* %N: the id of the unit without the suffix (foo@bar)
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* %p: the prefix (foo)
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* %i: the instance (bar)
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* %U the UID of the running user
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* %u the username of running user
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* %m the machine ID of the running system
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* %H the host name of the running system
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* %b the boot ID of the running system
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* %v `uname -r` of the running system
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*/
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const Specifier table[] = {
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{ 'n', specifier_string, i->name },
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{ 'N', specifier_prefix_and_instance, NULL },
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{ 'p', specifier_prefix, NULL },
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{ 'i', specifier_instance, NULL },
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{ 'U', specifier_user_id, NULL },
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{ 'u', specifier_user_name, NULL },
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{ 'm', specifier_machine_id, NULL },
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{ 'H', specifier_host_name, NULL },
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{ 'b', specifier_boot_id, NULL },
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{ 'v', specifier_kernel_release, NULL },
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{}
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};
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assert(i);
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assert(format);
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assert(ret);
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return specifier_printf(format, table, i, ret);
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}
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