81 lines
2.3 KiB
C
81 lines
2.3 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#include <errno.h>
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#include <unistd.h>
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#include "fs-util.h"
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#include "log.h"
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#include "proc-cmdline.h"
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#include "special.h"
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#include "string-util.h"
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#include "util.h"
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/*
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* Implements the logic described in systemd.offline-updates(7).
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*/
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static const char *arg_dest = "/tmp";
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static int generate_symlink(void) {
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const char *p = NULL;
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if (laccess("/system-update", F_OK) < 0) {
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if (errno == ENOENT)
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return 0;
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log_error_errno(errno, "Failed to check for system update: %m");
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return -EINVAL;
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}
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p = strjoina(arg_dest, "/" SPECIAL_DEFAULT_TARGET);
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if (symlink(SYSTEM_DATA_UNIT_PATH "/system-update.target", p) < 0)
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return log_error_errno(errno, "Failed to create symlink %s: %m", p);
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return 1;
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}
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static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {
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assert(key);
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/* Check if a run level is specified on the kernel command line. The
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* command line has higher priority than any on-disk configuration, so
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* it'll make any symlink we create moot.
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*/
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if (streq(key, "systemd.unit") && !proc_cmdline_value_missing(key, value))
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log_warning("Offline system update overridden by kernel command line systemd.unit= setting");
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else if (!value && runlevel_to_target(key))
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log_warning("Offline system update overridden by runlevel \"%s\" on the kernel command line", key);
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return 0;
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}
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int main(int argc, char *argv[]) {
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int r, k;
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if (argc > 1 && argc != 4) {
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log_error("This program takes three or no arguments.");
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return EXIT_FAILURE;
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}
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if (argc > 1)
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arg_dest = argv[2];
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log_set_prohibit_ipc(true);
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log_set_target(LOG_TARGET_AUTO);
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log_parse_environment();
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log_open();
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umask(0022);
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r = generate_symlink();
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if (r > 0) {
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k = proc_cmdline_parse(parse_proc_cmdline_item, NULL, 0);
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if (k < 0)
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log_warning_errno(k, "Failed to parse kernel command line, ignoring: %m");
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}
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return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
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}
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