Patches to allow one to allow one to specify a directory to chroot to.
This includes support for running a script to setup that directory. The kenv variables init_chroot and init_script control this behavior, and are documented in loader(8) that's about to be committed (along with the other variables like init_path...). Submitted by: Oliver Fromme Reviewed by: myself, jhb (earlier versions)
This commit is contained in:
Warner Losh
parent
f3b179a4b1
commit
1a7bec91fb
202
sbin/init/init.c
202
sbin/init/init.c
@ -55,6 +55,7 @@ static const char rcsid[] =
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#include <db.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <kenv.h>
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#include <libutil.h>
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#include <paths.h>
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#include <signal.h>
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@ -121,6 +122,8 @@ state_func_t clean_ttys(void);
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state_func_t catatonia(void);
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state_func_t death(void);
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state_func_t run_script(const char *);
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enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT;
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#define FALSE 0
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#define TRUE 1
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@ -131,9 +134,11 @@ int howto = RB_AUTOBOOT;
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int devfs;
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void transition(state_t);
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state_t requested_transition = runcom;
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state_t requested_transition;
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void setctty(const char *);
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const char *get_shell(void);
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void write_stderr(const char *message);
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typedef struct init_session {
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int se_index; /* index of entry in ttys file */
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@ -187,6 +192,8 @@ DB *session_db;
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int
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main(int argc, char *argv[])
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{
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state_t initial_transition = runcom;
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char kenv_value[PATH_MAX];
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int c;
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struct sigaction sa;
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sigset_t mask;
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@ -262,7 +269,7 @@ main(int argc, char *argv[])
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devfs = 1;
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break;
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case 's':
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requested_transition = single_user;
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initial_transition = single_user;
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break;
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case 'f':
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runcom_mode = FASTBOOT;
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@ -275,6 +282,63 @@ main(int argc, char *argv[])
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if (optind != argc)
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warning("ignoring excess arguments");
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/*
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* We catch or block signals rather than ignore them,
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* so that they get reset on exec.
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*/
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handle(badsys, SIGSYS, 0);
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handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV,
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SIGBUS, SIGXCPU, SIGXFSZ, 0);
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handle(transition_handler, SIGHUP, SIGINT, SIGTERM, SIGTSTP,
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SIGUSR1, SIGUSR2, 0);
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handle(alrm_handler, SIGALRM, 0);
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sigfillset(&mask);
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delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS,
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SIGXCPU, SIGXFSZ, SIGHUP, SIGINT, SIGTERM, SIGTSTP, SIGALRM,
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SIGUSR1, SIGUSR2, 0);
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sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
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sigemptyset(&sa.sa_mask);
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sa.sa_flags = 0;
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sa.sa_handler = SIG_IGN;
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(void) sigaction(SIGTTIN, &sa, (struct sigaction *)0);
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(void) sigaction(SIGTTOU, &sa, (struct sigaction *)0);
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/*
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* Paranoia.
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*/
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close(0);
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close(1);
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close(2);
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if (kenv(KENV_GET, "init_script", kenv_value, sizeof(kenv_value)) > 0) {
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state_func_t next_transition;
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if ((next_transition = run_script(kenv_value)) != 0)
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initial_transition = (state_t) next_transition;
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}
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if (kenv(KENV_GET, "init_chroot", kenv_value, sizeof(kenv_value)) > 0) {
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if (chdir(kenv_value) != 0 || chroot(".") != 0)
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warning("Can't chroot to %s: %m", kenv_value);
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}
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/*
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* Additional check if devfs needs to be mounted:
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* If "/" and "/dev" have the same device number,
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* then it hasn't been mounted yet.
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*/
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if (!devfs) {
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struct stat stst;
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dev_t root_devno;
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stat("/", &stst);
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root_devno = stst.st_dev;
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if (stat("/dev", &stst) != 0)
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warning("Can't stat /dev: %m");
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else if (stst.st_dev == root_devno)
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devfs++;
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}
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if (devfs) {
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struct iovec iov[4];
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char *s;
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@ -311,38 +375,10 @@ main(int argc, char *argv[])
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free(s);
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}
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/*
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* We catch or block signals rather than ignore them,
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* so that they get reset on exec.
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*/
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handle(badsys, SIGSYS, 0);
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handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV,
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SIGBUS, SIGXCPU, SIGXFSZ, 0);
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handle(transition_handler, SIGHUP, SIGINT, SIGTERM, SIGTSTP,
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SIGUSR1, SIGUSR2, 0);
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handle(alrm_handler, SIGALRM, 0);
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sigfillset(&mask);
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delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS,
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SIGXCPU, SIGXFSZ, SIGHUP, SIGINT, SIGTERM, SIGTSTP, SIGALRM,
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SIGUSR1, SIGUSR2, 0);
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sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
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sigemptyset(&sa.sa_mask);
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sa.sa_flags = 0;
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sa.sa_handler = SIG_IGN;
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(void) sigaction(SIGTTIN, &sa, (struct sigaction *)0);
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(void) sigaction(SIGTTOU, &sa, (struct sigaction *)0);
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/*
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* Paranoia.
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*/
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close(0);
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close(1);
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close(2);
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/*
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* Start the state machine.
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*/
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transition(requested_transition);
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transition(initial_transition);
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/*
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* Should never reach here.
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@ -558,6 +594,23 @@ setctty(const char *name)
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}
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}
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const char *
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get_shell(void)
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{
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static char kenv_value[PATH_MAX];
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if (kenv(KENV_GET, "init_shell", kenv_value, sizeof(kenv_value)) > 0)
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return kenv_value;
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else
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return _PATH_BSHELL;
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}
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void
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write_stderr(const char *message)
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{
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write(STDERR_FILENO, message, strlen(message));
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}
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/*
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* Bring the system up single user.
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*/
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@ -567,7 +620,7 @@ single_user(void)
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pid_t pid, wpid;
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int status;
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sigset_t mask;
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const char *shell = _PATH_BSHELL;
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const char *shell;
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char *argv[2];
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#ifdef SECURE
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struct ttyent *typ;
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@ -589,6 +642,8 @@ single_user(void)
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_exit(0);
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}
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shell = get_shell();
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if ((pid = fork()) == 0) {
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/*
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* Start the single user session.
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@ -605,7 +660,7 @@ single_user(void)
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pp = getpwnam("root");
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if (typ && (typ->ty_status & TTY_SECURE) == 0 &&
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pp && *pp->pw_passwd) {
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write(STDERR_FILENO, banner, sizeof banner - 1);
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write_stderr(banner);
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for (;;) {
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clear = getpass("Password:");
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if (clear == 0 || *clear == '\0')
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@ -626,10 +681,10 @@ single_user(void)
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char *cp = altshell;
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int num;
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#define SHREQUEST \
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"Enter full pathname of shell or RETURN for " _PATH_BSHELL ": "
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(void)write(STDERR_FILENO,
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SHREQUEST, sizeof(SHREQUEST) - 1);
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#define SHREQUEST "Enter full pathname of shell or RETURN for "
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write_stderr(SHREQUEST);
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write_stderr(shell);
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write_stderr(": ");
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while ((num = read(STDIN_FILENO, cp, 1)) != -1 &&
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num != 0 && *cp != '\n' && cp < &altshell[127])
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cp++;
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@ -717,12 +772,36 @@ single_user(void)
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*/
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state_func_t
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runcom(void)
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{
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state_func_t next_transition;
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if ((next_transition = run_script(_PATH_RUNCOM)) != 0)
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return next_transition;
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runcom_mode = AUTOBOOT; /* the default */
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/* NB: should send a message to the session logger to avoid blocking. */
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logwtmp("~", "reboot", "");
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return (state_func_t) read_ttys;
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}
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/*
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* Run a shell script.
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* Returns 0 on success, otherwise the next transition to enter:
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* - single_user if fork/execv/waitpid failed, or if the script
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* terminated with a signal or exit code != 0.
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* - death if a SIGTERM was delivered to init(8).
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*/
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state_func_t
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run_script(const char *script)
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{
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pid_t pid, wpid;
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int status;
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char *argv[4];
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const char *shell;
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struct sigaction sa;
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shell = get_shell();
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if ((pid = fork()) == 0) {
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sigemptyset(&sa.sa_mask);
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sa.sa_flags = 0;
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@ -733,11 +812,10 @@ runcom(void)
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setctty(_PATH_CONSOLE);
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char _sh[] = "sh";
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char _path_runcom[] = _PATH_RUNCOM;
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char _autoboot[] = "autoboot";
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argv[0] = _sh;
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argv[1] = _path_runcom;
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argv[1] = __DECONST(char *, script);
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argv[2] = runcom_mode == AUTOBOOT ? _autoboot : 0;
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argv[3] = 0;
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@ -746,14 +824,13 @@ runcom(void)
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#ifdef LOGIN_CAP
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setprocresources(RESOURCE_RC);
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#endif
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execv(_PATH_BSHELL, argv);
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stall("can't exec %s for %s: %m", _PATH_BSHELL, _PATH_RUNCOM);
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execv(shell, argv);
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stall("can't exec %s for %s: %m", shell, script);
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_exit(1); /* force single user mode */
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}
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if (pid == -1) {
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emergency("can't fork for %s on %s: %m",
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_PATH_BSHELL, _PATH_RUNCOM);
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emergency("can't fork for %s on %s: %m", shell, script);
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while (waitpid(-1, (int *) 0, WNOHANG) > 0)
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continue;
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sleep(STALL_TIMEOUT);
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@ -772,13 +849,13 @@ runcom(void)
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return (state_func_t) death;
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if (errno == EINTR)
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continue;
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warning("wait for %s on %s failed: %m; going to single user mode",
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_PATH_BSHELL, _PATH_RUNCOM);
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warning("wait for %s on %s failed: %m; going to "
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"single user mode", shell, script);
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return (state_func_t) single_user;
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}
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if (wpid == pid && WIFSTOPPED(status)) {
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warning("init: %s on %s stopped, restarting\n",
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_PATH_BSHELL, _PATH_RUNCOM);
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shell, script);
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kill(pid, SIGCONT);
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wpid = -1;
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}
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@ -795,18 +872,15 @@ runcom(void)
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}
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if (!WIFEXITED(status)) {
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warning("%s on %s terminated abnormally, going to single user mode",
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_PATH_BSHELL, _PATH_RUNCOM);
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warning("%s on %s terminated abnormally, going to single "
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"user mode", shell, script);
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return (state_func_t) single_user;
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}
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if (WEXITSTATUS(status))
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return (state_func_t) single_user;
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runcom_mode = AUTOBOOT; /* the default */
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/* NB: should send a message to the session logger to avoid blocking. */
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logwtmp("~", "reboot", "");
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return (state_func_t) read_ttys;
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return (state_func_t) 0;
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}
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/*
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@ -1465,6 +1539,7 @@ runshutdown(void)
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int shutdowntimeout;
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size_t len;
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char *argv[4];
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const char *shell;
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struct sigaction sa;
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struct stat sb;
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@ -1477,6 +1552,8 @@ runshutdown(void)
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if (stat(_PATH_RUNDOWN, &sb) == -1 && errno == ENOENT)
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return 0;
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shell = get_shell();
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if ((pid = fork()) == 0) {
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int fd;
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@ -1517,14 +1594,13 @@ runshutdown(void)
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#ifdef LOGIN_CAP
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setprocresources(RESOURCE_RC);
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#endif
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execv(_PATH_BSHELL, argv);
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warning("can't exec %s for %s: %m", _PATH_BSHELL, _PATH_RUNDOWN);
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execv(shell, argv);
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warning("can't exec %s for %s: %m", shell, _PATH_RUNDOWN);
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_exit(1); /* force single user mode */
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}
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if (pid == -1) {
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emergency("can't fork for %s on %s: %m",
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_PATH_BSHELL, _PATH_RUNDOWN);
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emergency("can't fork for %s on %s: %m", shell, _PATH_RUNDOWN);
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while (waitpid(-1, (int *) 0, WNOHANG) > 0)
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continue;
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sleep(STALL_TIMEOUT);
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@ -1548,20 +1624,20 @@ runshutdown(void)
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if (clang == 1) {
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/* we were waiting for the sub-shell */
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kill(wpid, SIGTERM);
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warning("timeout expired for %s on %s: %m; going to single user mode",
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_PATH_BSHELL, _PATH_RUNDOWN);
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warning("timeout expired for %s on %s: %m; going to "
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"single user mode", shell, _PATH_RUNDOWN);
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return -1;
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}
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if (wpid == -1) {
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if (errno == EINTR)
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continue;
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warning("wait for %s on %s failed: %m; going to single user mode",
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_PATH_BSHELL, _PATH_RUNDOWN);
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warning("wait for %s on %s failed: %m; going to "
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"single user mode", shell, _PATH_RUNDOWN);
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return -1;
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}
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if (wpid == pid && WIFSTOPPED(status)) {
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warning("init: %s on %s stopped, restarting\n",
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_PATH_BSHELL, _PATH_RUNDOWN);
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shell, _PATH_RUNDOWN);
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kill(pid, SIGCONT);
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wpid = -1;
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}
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@ -1584,8 +1660,8 @@ runshutdown(void)
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}
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if (!WIFEXITED(status)) {
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warning("%s on %s terminated abnormally, going to single user mode",
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_PATH_BSHELL, _PATH_RUNDOWN);
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warning("%s on %s terminated abnormally, going to "
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"single user mode", shell, _PATH_RUNDOWN);
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return -2;
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}
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Block a user