diff options
| -rw-r--r-- | src/missing.h | 4 | ||||
| -rw-r--r-- | src/shutdown.c | 102 |
2 files changed, 106 insertions, 0 deletions
diff --git a/src/missing.h b/src/missing.h index 23ab39e65..a44390074 100644 --- a/src/missing.h +++ b/src/missing.h @@ -172,4 +172,8 @@ struct btrfs_ioctl_vol_args { #define MS_MOVE 8192 #endif +#ifndef MS_PRIVATE +#define MS_PRIVATE (1 << 18) +#endif + #endif diff --git a/src/shutdown.c b/src/shutdown.c index a2f3b539b..528b30b98 100644 --- a/src/shutdown.c +++ b/src/shutdown.c @@ -24,6 +24,11 @@ #include <sys/reboot.h> #include <linux/reboot.h> #include <sys/wait.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <sys/mount.h> +#include <sys/syscall.h> +#include <fcntl.h> #include <dirent.h> #include <errno.h> #include <unistd.h> @@ -32,12 +37,14 @@ #include <stdlib.h> #include <string.h> +#include "missing.h" #include "log.h" #include "umount.h" #include "util.h" #define TIMEOUT_USEC (5 * USEC_PER_SEC) #define FINALIZE_ATTEMPTS 50 +#define pivot_root(new_root,put_old) syscall(SYS_pivot_root,new_root,put_old) static bool ignore_proc(pid_t pid) { if (pid == 1) @@ -192,6 +199,90 @@ finish: sigprocmask(SIG_SETMASK, &oldmask, NULL); } +static bool prepare_new_root(void) { + int r = false; + const char *dirs[] = { "/run/initramfs/oldroot", + "/run/initramfs/proc", + "/run/initramfs/sys", + "/run/initramfs/dev", + "/run/initramfs/run", + NULL }; + const char **dir; + const char *msg; + + msg = "Failed to mount bind /run/initramfs on /run/initramfs"; + if (mount("/run/initramfs", "/run/initramfs", NULL, MS_BIND, NULL) != 0) + goto out; + + msg="Failed to make /run/initramfs private mount %m:"; + if (mount(NULL, "/run/initramfs", NULL, MS_PRIVATE, NULL) != 0) + goto out; + + for (dir = &dirs[0]; *dir != NULL; dir++) { + asprintf((char **) &msg, "mkdir %s: %%m", *dir); + if (mkdir(*dir, 0755) != 0) { + if (errno != EEXIST) + goto out; + } + free((char *) msg); + } + + msg = "Failed to mount bind /sys on /run/initramfs/sys"; + if (mount("/sys", "/run/initramfs/sys", NULL, MS_BIND, NULL) != 0) + goto out; + msg = "Failed to mount bind /proc on /run/initramfs/proc"; + if (mount("/proc", "/run/initramfs/proc", NULL, MS_BIND, NULL) != 0) + goto out; + msg = "Failed to mount bind /dev on /run/initramfs/dev"; + if (mount("/dev", "/run/initramfs/dev", NULL, MS_BIND, NULL) != 0) + goto out; + msg = "Failed to mount bind /run on /run/initramfs/run"; + if (mount("/run", "/run/initramfs/run", NULL, MS_BIND, NULL) != 0) + goto out; + + r = true; + out: + if (!r) + log_error("%s: %m", msg); + return r; +} + +static bool pivot_to_new_root(void) { + int fd; + int r = 0; + chdir("/run/initramfs"); + + /* + In case some evil process made "/" MS_SHARED + It works for pivot_root, but the ref count for the root device + is not decreasing :-/ + */ + if (mount(NULL, "/", NULL, MS_PRIVATE, NULL) != 0) { + log_error("Failed to make \"/\" private mount %m: "); + return false; + } + + r = pivot_root(".", "oldroot"); + if (r!=0) { + log_error("pivot failed: %m"); + /* only chroot, if pivot root succeded */ + return false; + } + chroot("."); + log_info("pivot rooted"); + + fd = open("dev/console", O_RDONLY); + dup2(fd, STDIN_FILENO); + close_nointr_nofail(fd); + fd = open("dev/console", O_WRONLY); + dup2(fd, STDOUT_FILENO); + close_nointr_nofail(fd); + fd = open("dev/console", O_WRONLY); + dup2(fd, STDERR_FILENO); + close_nointr_nofail(fd); + return true; +} + int main(int argc, char *argv[]) { int cmd, r; unsigned retries; @@ -330,6 +421,17 @@ int main(int argc, char *argv[]) { sync(); + if (access("/run/initramfs/shutdown", X_OK) == 0) { + char *new_argv[3]; + new_argv[0] = strdup(argv[0]); + new_argv[1] = strdup(argv[1]); + new_argv[2] = NULL; + if (prepare_new_root() && pivot_to_new_root()) { + execv("/shutdown", new_argv); + log_error("Failed to execute shutdown binary: %m"); + } + } + if (cmd == LINUX_REBOOT_CMD_KEXEC) { /* We cheat and exec kexec to avoid doing all its work */ pid_t pid = fork(); |