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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <errno.h>
#include <unistd.h>
#include "fs-util.h"
#include "generator.h"
#include "initrd-util.h"
#include "log.h"
#include "path-util.h"
#include "proc-cmdline.h"
#include "special.h"
#include "string-util.h"
#include "unit-file.h"
/*
* Implements the logic described in systemd.offline-updates(7).
*/
static const char *arg_dest = NULL;
static int generate_symlink(void) {
int r;
FOREACH_STRING(p, "/system-update", "/etc/system-update") {
r = access_nofollow(p, F_OK);
if (r < 0) {
if (r != -ENOENT)
log_warning_errno(r, "Failed to check if %s symlink exists, ignoring: %m", p);
continue;
}
_cleanup_free_ char *j = NULL;
j = path_join(arg_dest, SPECIAL_DEFAULT_TARGET);
if (!j)
return log_oom();
if (symlink(SYSTEM_DATA_UNIT_DIR "/system-update.target", j) < 0)
return log_error_errno(errno, "Failed to create symlink %s: %m", j);
return 1;
}
return 0;
}
static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {
assert(key);
/* Check if a run level is specified on the kernel command line. The
* command line has higher priority than any on-disk configuration, so
* it'll make any symlink we create moot.
*/
if (streq(key, "systemd.unit") && !proc_cmdline_value_missing(key, value))
log_warning("Offline system update overridden by kernel command line systemd.unit= setting");
else if (!value && runlevel_to_target(key))
log_warning("Offline system update overridden by runlevel \"%s\" on the kernel command line", key);
return 0;
}
static int run(const char *dest, const char *dest_early, const char *dest_late) {
int r;
assert_se(arg_dest = dest_early);
if (in_initrd()) {
log_debug("Skipping generator, running in the initrd.");
return EXIT_SUCCESS;
}
r = generate_symlink();
if (r <= 0)
return r;
/* We parse the command line only to emit warnings. */
r = proc_cmdline_parse(parse_proc_cmdline_item, NULL, 0);
if (r < 0)
log_warning_errno(r, "Failed to parse kernel command line, ignoring: %m");
return 0;
}
DEFINE_MAIN_GENERATOR_FUNCTION(run);
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