mirror of
https://github.com/morgan9e/systemd
synced 2026-04-15 00:47:10 +09:00
119 lines
4.2 KiB
C
119 lines
4.2 KiB
C
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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#include "argv-util.h"
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#include "bus-error.h"
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#include "bus-locator.h"
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#include "chase.h"
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#include "fd-util.h"
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#include "initrd-util.h"
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#include "parse-util.h"
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#include "path-util.h"
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#include "proc-cmdline.h"
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#include "signal-util.h"
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#include "stat-util.h"
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#include "systemctl.h"
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#include "systemctl-switch-root.h"
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#include "systemctl-util.h"
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static int same_file_in_root(
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const char *root,
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const char *a,
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const char *b) {
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struct stat sta, stb;
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int r;
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r = chase_and_stat(a, root, CHASE_PREFIX_ROOT, NULL, &sta);
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if (r < 0)
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return r;
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r = chase_and_stat(b, root, CHASE_PREFIX_ROOT, NULL, &stb);
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if (r < 0)
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return r;
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return stat_inode_same(&sta, &stb);
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}
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int verb_switch_root(int argc, char *argv[], void *userdata) {
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_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
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_cleanup_free_ char *cmdline_init = NULL;
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const char *root, *init;
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sd_bus *bus;
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int r;
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if (arg_transport != BUS_TRANSPORT_LOCAL)
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return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Cannot switch root remotely.");
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if (argc > 3)
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return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Too many arguments.");
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if (argc >= 2) {
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root = argv[1];
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if (!path_is_valid(root))
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return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Invalid root path: %s", root);
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if (!path_is_absolute(root))
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return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Root path is not absolute: %s", root);
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r = path_is_root(root);
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if (r < 0)
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return log_error_errno(r, "Failed to check if switch-root directory '%s' is current root: %m", root);
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if (r > 0)
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return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Cannot switch to current root directory: %s", root);
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} else
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root = "/sysroot";
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if (!in_initrd())
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return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Not in initrd, refusing switch-root operation.");
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if (argc >= 3)
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init = argv[2];
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else {
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r = proc_cmdline_get_key("init", 0, &cmdline_init);
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if (r < 0)
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log_debug_errno(r, "Failed to parse /proc/cmdline: %m");
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init = cmdline_init;
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}
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init = empty_to_null(init);
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if (init) {
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if (!path_is_valid(init))
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return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Invalid path to init binary: %s", init);
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if (!path_is_absolute(init))
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return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Path to init binary is not absolute: %s", init);
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/* If the passed init is actually the same as the systemd binary, then let's suppress it. */
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if (same_file_in_root(root, SYSTEMD_BINARY_PATH, init) > 0)
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init = NULL;
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}
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/* Instruct PID1 to exclude us from its killing spree applied during the transition. Otherwise we
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* would exit with a failure status even though the switch to the new root has succeed. */
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assert(saved_argv);
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assert(saved_argv[0]);
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saved_argv[0][0] = '@';
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r = acquire_bus(BUS_MANAGER, &bus);
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if (r < 0)
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return r;
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/* If we are slow to exit after the root switch, the new systemd instance will send us a signal to
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* terminate. Just ignore it and exit normally. This way the unit does not end up as failed. */
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r = ignore_signals(SIGTERM);
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if (r < 0)
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log_warning_errno(r, "Failed to change disposition of SIGTERM to ignore: %m");
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log_debug("Switching root - root: %s; init: %s", root, strna(init));
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r = bus_call_method(bus, bus_systemd_mgr, "SwitchRoot", &error, NULL, "ss", root, init);
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if (r < 0) {
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(void) default_signals(SIGTERM);
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return log_error_errno(r, "Failed to switch root: %s", bus_error_message(&error, r));
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}
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return 0;
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}
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