diff options
| -rw-r--r-- | src/volatile-root/volatile-root.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/src/volatile-root/volatile-root.c b/src/volatile-root/volatile-root.c index 02f6d31b05..701f5a2832 100644 --- a/src/volatile-root/volatile-root.c +++ b/src/volatile-root/volatile-root.c @@ -3,6 +3,7 @@ #include <sys/mount.h> #include "alloc-util.h" +#include "blockdev-util.h" #include "escape.h" #include "fs-util.h" #include "main-func.h" @@ -115,6 +116,7 @@ finish: static int run(int argc, char *argv[]) { VolatileMode m = _VOLATILE_MODE_INVALID; const char *path; + dev_t devt; int r; log_setup_service(); @@ -166,6 +168,24 @@ static int run(int argc, char *argv[]) { return 0; } + /* We are about to replace the root directory with something else. Later code might want to know what we + * replaced here, hence let's save that information as a symlink we can later use. (This is particularly + * relevant for the overlayfs case where we'll fully obstruct the view onto the underlying device, hence + * querying the backing device node from the file system directly is no longer possible. */ + r = get_block_device_harder(path, &devt); + if (r < 0) + return log_error_errno(r, "Failed to determine device major/minor of %s: %m", path); + else if (r > 0) { + _cleanup_free_ char *dn = NULL; + + r = device_path_make_major_minor(S_IFBLK, devt, &dn); + if (r < 0) + return log_error_errno(r, "Failed to format device node path: %m"); + + if (symlink(dn, "/run/systemd/volatile-root") < 0) + log_warning_errno(errno, "Failed to create symlink /run/systemd/volatile-root: %m"); + } + if (m == VOLATILE_YES) return make_volatile(path); else { |