91214a37ef
This adds support for a new kernel command line option "systemd.volatile=" that provides the same functionality that systemd-nspawn's --volatile= switch provides, but for host systems (i.e. systems booting with a kernel). It takes the same parameter and has the same effect. In order to implement systemd.volatile=yes a new service systemd-volatile-root.service is introduced that only runs in the initrd and rearranges the root directory as needed to become a tmpfs instance. Note that systemd.volatile=state is implemented different: it simply generates a var.mount unit file that is part of the normal boot and has no effect on the initrd execution. The way this is implemented ensures that other explicit configuration for /var can always override the effect of these options. Specifically, the var.mount unit is generated in the "late" generator directory, so that it only is in effect if nothing else overrides it.
69 lines
1.8 KiB
C
69 lines
1.8 KiB
C
/***
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This file is part of systemd.
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Copyright 2015 Lennart Poettering
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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 "alloc-util.h"
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#include "macro.h"
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#include "parse-util.h"
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#include "proc-cmdline.h"
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#include "string-util.h"
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#include "volatile-util.h"
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VolatileMode volatile_mode_from_string(const char *s) {
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int b;
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if (isempty(s))
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return _VOLATILE_MODE_INVALID;
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b = parse_boolean(s);
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if (b > 0)
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return VOLATILE_YES;
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if (b == 0)
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return VOLATILE_NO;
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if (streq(s, "state"))
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return VOLATILE_STATE;
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return _VOLATILE_MODE_INVALID;
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}
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int query_volatile_mode(VolatileMode *ret) {
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_cleanup_free_ char *mode = NULL;
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VolatileMode m = VOLATILE_NO;
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int r;
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r = proc_cmdline_get_key("systemd.volatile", PROC_CMDLINE_VALUE_OPTIONAL, &mode);
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if (r < 0)
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return r;
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if (r == 0)
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goto finish;
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if (mode) {
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m = volatile_mode_from_string(mode);
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if (m < 0)
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return -EINVAL;
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} else
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m = VOLATILE_YES;
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r = 1;
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finish:
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*ret = m;
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return r;
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}
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