diff options
Diffstat (limited to 'sbin/init/init.c')
-rw-r--r-- | sbin/init/init.c | 284 |
1 files changed, 269 insertions, 15 deletions
diff --git a/sbin/init/init.c b/sbin/init/init.c index edc38e6..0826507 100644 --- a/sbin/init/init.c +++ b/sbin/init/init.c @@ -46,6 +46,7 @@ static const char rcsid[] = #include <sys/param.h> #include <sys/ioctl.h> +#include <sys/mman.h> #include <sys/mount.h> #include <sys/sysctl.h> #include <sys/wait.h> @@ -79,6 +80,7 @@ static const char rcsid[] = #include <login_cap.h> #endif +#include "mntopts.h" #include "pathnames.h" /* @@ -103,6 +105,7 @@ static void warning(const char *, ...) __printflike(1, 2); static void emergency(const char *, ...) __printflike(1, 2); static void disaster(int); static void badsys(int); +static void revoke_ttys(void); static int runshutdown(void); static char *strk(char *); @@ -122,6 +125,8 @@ static state_func_t clean_ttys(void); static state_func_t catatonia(void); static state_func_t death(void); static state_func_t death_single(void); +static state_func_t reroot(void); +static state_func_t reroot_phase_two(void); static state_func_t run_script(const char *); @@ -193,7 +198,7 @@ main(int argc, char *argv[]) { state_t initial_transition = runcom; char kenv_value[PATH_MAX]; - int c; + int c, error; struct sigaction sa; sigset_t mask; @@ -226,6 +231,9 @@ main(int argc, char *argv[]) case 'q': /* rescan /etc/ttys */ sig = SIGHUP; break; + case 'r': /* remount root */ + sig = SIGEMT; + break; default: goto invalid; } @@ -247,7 +255,7 @@ invalid: /* * Create an initial session. */ - if (setsid() < 0) + if (setsid() < 0 && (errno != EPERM || getsid(0) != 1)) warning("initial setsid() failed: %m"); /* @@ -261,7 +269,7 @@ invalid: * This code assumes that we always get arguments through flags, * never through bits set in some random machine register. */ - while ((c = getopt(argc, argv, "dsf")) != -1) + while ((c = getopt(argc, argv, "dsfr")) != -1) switch (c) { case 'd': devfs = 1; @@ -272,6 +280,9 @@ invalid: case 'f': runcom_mode = FASTBOOT; break; + case 'r': + initial_transition = reroot_phase_two; + break; default: warning("unrecognized flag '-%c'", c); break; @@ -287,13 +298,13 @@ invalid: handle(badsys, SIGSYS, 0); handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGXCPU, SIGXFSZ, 0); - handle(transition_handler, SIGHUP, SIGINT, SIGTERM, SIGTSTP, SIGUSR1, - SIGUSR2, 0); + handle(transition_handler, SIGHUP, SIGINT, SIGEMT, SIGTERM, SIGTSTP, + SIGUSR1, SIGUSR2, 0); handle(alrm_handler, SIGALRM, 0); sigfillset(&mask); delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS, - SIGXCPU, SIGXFSZ, SIGHUP, SIGINT, SIGTERM, SIGTSTP, SIGALRM, - SIGUSR1, SIGUSR2, 0); + SIGXCPU, SIGXFSZ, SIGHUP, SIGINT, SIGEMT, SIGTERM, SIGTSTP, + SIGALRM, SIGUSR1, SIGUSR2, 0); sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0); sigemptyset(&sa.sa_mask); sa.sa_flags = 0; @@ -373,6 +384,16 @@ invalid: free(s); } + if (initial_transition != reroot_phase_two) { + /* + * Unmount reroot leftovers. This runs after init(8) + * gets reexecuted after reroot_phase_two() is done. + */ + error = unmount(_PATH_REROOT, MNT_FORCE); + if (error != 0 && errno != EINVAL) + warning("Cannot unmount %s: %m", _PATH_REROOT); + } + /* * Start the state machine. */ @@ -620,6 +641,228 @@ write_stderr(const char *message) write(STDERR_FILENO, message, strlen(message)); } +static int +read_file(const char *path, void **bufp, size_t *bufsizep) +{ + struct stat sb; + size_t bufsize; + void *buf; + ssize_t nbytes; + int error, fd; + + fd = open(path, O_RDONLY); + if (fd < 0) { + emergency("%s: %s", path, strerror(errno)); + return (-1); + } + + error = fstat(fd, &sb); + if (error != 0) { + emergency("fstat: %s", strerror(errno)); + return (error); + } + + bufsize = sb.st_size; + buf = malloc(bufsize); + if (buf == NULL) { + emergency("malloc: %s", strerror(errno)); + return (error); + } + + nbytes = read(fd, buf, bufsize); + if (nbytes != (ssize_t)bufsize) { + emergency("read: %s", strerror(errno)); + free(buf); + return (error); + } + + error = close(fd); + if (error != 0) { + emergency("close: %s", strerror(errno)); + free(buf); + return (error); + } + + *bufp = buf; + *bufsizep = bufsize; + + return (0); +} + +static int +create_file(const char *path, void *buf, size_t bufsize) +{ + ssize_t nbytes; + int error, fd; + + fd = open(path, O_WRONLY | O_CREAT | O_EXCL, 0700); + if (fd < 0) { + emergency("%s: %s", path, strerror(errno)); + return (-1); + } + + nbytes = write(fd, buf, bufsize); + if (nbytes != (ssize_t)bufsize) { + emergency("write: %s", strerror(errno)); + return (-1); + } + + error = close(fd); + if (error != 0) { + emergency("close: %s", strerror(errno)); + free(buf); + return (-1); + } + + return (0); +} + +static int +mount_tmpfs(const char *fspath) +{ + struct iovec *iov; + char errmsg[255]; + int error, iovlen; + + iov = NULL; + iovlen = 0; + memset(errmsg, 0, sizeof(errmsg)); + build_iovec(&iov, &iovlen, "fstype", + __DECONST(void *, "tmpfs"), (size_t)-1); + build_iovec(&iov, &iovlen, "fspath", + __DECONST(void *, fspath), (size_t)-1); + build_iovec(&iov, &iovlen, "errmsg", + errmsg, sizeof(errmsg)); + + error = nmount(iov, iovlen, 0); + if (error != 0) { + if (*errmsg != '\0') { + emergency("cannot mount tmpfs on %s: %s: %s", + fspath, errmsg, strerror(errno)); + } else { + emergency("cannot mount tmpfs on %s: %s", + fspath, strerror(errno)); + } + return (error); + } + return (0); +} + +static state_func_t +reroot(void) +{ + void *buf; + char init_path[PATH_MAX]; + size_t bufsize, init_path_len; + int error, name[4]; + + name[0] = CTL_KERN; + name[1] = KERN_PROC; + name[2] = KERN_PROC_PATHNAME; + name[3] = -1; + init_path_len = sizeof(init_path); + error = sysctl(name, 4, init_path, &init_path_len, NULL, 0); + if (error != 0) { + emergency("failed to get kern.proc.pathname: %s", + strerror(errno)); + goto out; + } + + revoke_ttys(); + runshutdown(); + + /* + * Make sure nobody can interfere with our scheme. + */ + error = kill(-1, SIGKILL); + if (error != 0) { + emergency("kill(2) failed: %s", strerror(errno)); + goto out; + } + + /* + * Pacify GCC. + */ + buf = NULL; + bufsize = 0; + + /* + * Copy the init binary into tmpfs, so that we can unmount + * the old rootfs without committing suicide. + */ + error = read_file(init_path, &buf, &bufsize); + if (error != 0) + goto out; + error = mount_tmpfs(_PATH_REROOT); + if (error != 0) + goto out; + error = create_file(_PATH_REROOT_INIT, buf, bufsize); + if (error != 0) + goto out; + + /* + * Execute the temporary init. + */ + execl(_PATH_REROOT_INIT, _PATH_REROOT_INIT, "-r", NULL); + emergency("cannot exec %s: %s", _PATH_REROOT_INIT, strerror(errno)); + +out: + emergency("reroot failed; going to single user mode"); + return (state_func_t) single_user; +} + +static state_func_t +reroot_phase_two(void) +{ + char init_path[PATH_MAX], *path, *path_component; + size_t init_path_len; + int nbytes, error; + + /* + * Ask the kernel to mount the new rootfs. + */ + error = reboot(RB_REROOT); + if (error != 0) { + emergency("RB_REBOOT failed: %s", strerror(errno)); + goto out; + } + + /* + * Figure out where the destination init(8) binary is. Note that + * the path could be different than what we've started with. Use + * the value from kenv, if set, or the one from sysctl otherwise. + * The latter defaults to a hardcoded value, but can be overridden + * by a build time option. + */ + nbytes = kenv(KENV_GET, "init_path", init_path, sizeof(init_path)); + if (nbytes <= 0) { + init_path_len = sizeof(init_path); + error = sysctlbyname("kern.init_path", + init_path, &init_path_len, NULL, 0); + if (error != 0) { + emergency("failed to retrieve kern.init_path: %s", + strerror(errno)); + goto out; + } + } + + /* + * Repeat the init search logic from sys/kern/init_path.c + */ + path_component = init_path; + while ((path = strsep(&path_component, ":")) != NULL) { + /* + * Execute init(8) from the new rootfs. + */ + execl(path, path, NULL); + } + emergency("cannot exec init from %s: %s", init_path, strerror(errno)); + +out: + emergency("reroot failed; going to single user mode"); + return (state_func_t) single_user; +} + /* * Bring the system up single user. */ @@ -851,8 +1094,9 @@ run_script(const char *script) if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1) collect_child(wpid); if (wpid == -1) { - if (requested_transition == death_single) - return (state_func_t) death_single; + if (requested_transition == death_single || + requested_transition == reroot) + return (state_func_t) requested_transition; if (errno == EINTR) continue; warning("wait for %s on %s failed: %m; going to " @@ -1323,6 +1567,9 @@ transition_handler(int sig) current_state == multi_user || current_state == catatonia) requested_transition = catatonia; break; + case SIGEMT: + requested_transition = reroot; + break; default: requested_transition = 0; break; @@ -1486,7 +1733,6 @@ alrm_handler(int sig) static state_func_t death(void) { - session_t *sp; int block, blocked; size_t len; @@ -1503,11 +1749,7 @@ death(void) * runshutdown() will perform the initial open() call, causing * the terminal attributes to be misconfigured. */ - for (sp = sessions; sp; sp = sp->se_next) { - sp->se_flags |= SE_SHUTDOWN; - kill(sp->se_process, SIGHUP); - revoke(sp->se_device); - } + revoke_ttys(); /* Try to run the rc.shutdown script within a period of time */ runshutdown(); @@ -1553,6 +1795,18 @@ death_single(void) return (state_func_t) single_user; } +static void +revoke_ttys(void) +{ + session_t *sp; + + for (sp = sessions; sp; sp = sp->se_next) { + sp->se_flags |= SE_SHUTDOWN; + kill(sp->se_process, SIGHUP); + revoke(sp->se_device); + } +} + /* * Run the system shutdown script. * |