126 lines
4.3 KiB
C
126 lines
4.3 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#include <sys/mount.h>
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#include "alloc-util.h"
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#include "fs-util.h"
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#include "main-func.h"
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#include "mkdir.h"
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#include "mount-util.h"
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#include "mountpoint-util.h"
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#include "path-util.h"
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#include "stat-util.h"
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#include "string-util.h"
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#include "volatile-util.h"
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static int make_volatile(const char *path) {
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_cleanup_free_ char *old_usr = NULL;
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int r;
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r = path_is_mount_point(path, NULL, AT_SYMLINK_FOLLOW);
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if (r < 0)
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return log_error_errno(r, "Couldn't determine whether %s is a mount point: %m", path);
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if (r == 0)
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return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
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"%s is not a mount point.", path);
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r = path_is_temporary_fs(path);
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if (r < 0)
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return log_error_errno(r, "Couldn't determine whether %s is a temporary file system: %m", path);
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if (r > 0) {
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log_info("%s already is a temporary file system.", path);
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return 0;
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}
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r = chase_symlinks("/usr", path, CHASE_PREFIX_ROOT, &old_usr);
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if (r < 0)
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return log_error_errno(r, "/usr not available in old root: %m");
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r = mkdir_p("/run/systemd/volatile-sysroot", 0700);
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if (r < 0)
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return log_error_errno(r, "Couldn't generate volatile sysroot directory: %m");
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r = mount_verbose(LOG_ERR, "tmpfs", "/run/systemd/volatile-sysroot", "tmpfs", MS_STRICTATIME, "mode=755");
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if (r < 0)
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goto finish_rmdir;
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if (mkdir("/run/systemd/volatile-sysroot/usr", 0755) < 0) {
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r = -errno;
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goto finish_umount;
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}
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r = mount_verbose(LOG_ERR, old_usr, "/run/systemd/volatile-sysroot/usr", NULL, MS_BIND|MS_REC, NULL);
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if (r < 0)
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goto finish_umount;
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r = bind_remount_recursive("/run/systemd/volatile-sysroot/usr", true, NULL);
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if (r < 0)
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goto finish_umount;
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r = umount_recursive(path, 0);
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if (r < 0) {
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log_error_errno(r, "Failed to unmount %s: %m", path);
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goto finish_umount;
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}
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if (mount(NULL, "/", NULL, MS_SLAVE|MS_REC, NULL) < 0)
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log_warning_errno(errno, "Failed to remount %s MS_SLAVE|MS_REC: %m", path);
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r = mount_verbose(LOG_ERR, "/run/systemd/volatile-sysroot", path, NULL, MS_MOVE, NULL);
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finish_umount:
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(void) umount_recursive("/run/systemd/volatile-sysroot", 0);
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finish_rmdir:
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(void) rmdir("/run/systemd/volatile-sysroot");
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return r;
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}
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static int run(int argc, char *argv[]) {
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VolatileMode m = _VOLATILE_MODE_INVALID;
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const char *path;
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int r;
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log_setup_service();
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if (argc > 3)
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return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
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"Too many arguments. Expected directory and mode.");
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r = query_volatile_mode(&m);
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if (r < 0)
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return log_error_errno(r, "Failed to determine volatile mode from kernel command line.");
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if (r == 0 && argc >= 2) {
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/* The kernel command line always wins. However if nothing was set there, the argument passed here wins instead. */
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m = volatile_mode_from_string(argv[1]);
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if (m < 0) {
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log_error("Couldn't parse volatile mode: %s", argv[1]);
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r = -EINVAL;
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}
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}
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if (argc < 3)
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path = "/sysroot";
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else {
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path = argv[2];
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if (isempty(path))
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return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
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"Directory name cannot be empty.");
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if (!path_is_absolute(path))
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return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
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"Directory must be specified as absolute path.");
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if (path_equal(path, "/"))
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return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
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"Directory cannot be the root directory.");
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}
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if (m != VOLATILE_YES)
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return 0;
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return make_volatile(path);
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}
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DEFINE_MAIN_FUNCTION(run);
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