[apple/launchd.git] / launchd / src / init.c

/*
 * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_APACHE_LICENSE_HEADER_START@
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 * @APPLE_APACHE_LICENSE_HEADER_END@
 */
/*-
 * Copyright (c) 1991, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Donn Seeley at Berkeley Software Design, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

static const char *const __rcs_file_version__ = "$Revision: 1.38 $";

#include <Security/Authorization.h>
#include <Security/AuthorizationTags.h>
#include <Security/AuthSession.h>

#include <sys/types.h>
#include <sys/queue.h>
#include <sys/param.h>
#include <sys/mount.h>
#include <sys/sysctl.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <sys/resource.h>

#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <stdbool.h>
#include <string.h>
#include <syslog.h>
#include <time.h>
#include <ttyent.h>
#include <unistd.h>
#include <paths.h>
#include <util.h>
#include <libgen.h>
#include <paths.h>
#include <termios.h>

#include "launchd.h"

#define _PATH_RUNCOM            "/etc/rc"

/*
 * Sleep times; used to prevent thrashing.
 */
#define GETTY_SPACING            5      /* N secs minimum getty spacing */
#define GETTY_SLEEP             30      /* sleep N secs after spacing problem */
#define STALL_TIMEOUT           30      /* wait N secs after warning */
#define DEATH_WATCH             10      /* wait N secs for procs to die */
#define FAILED_HW_PASS           5      /* wait N secs before croaking user */

static void stall(char *, ...);

static void single_user_callback(void *, struct kevent *);
static kq_callback kqsingle_user_callback = single_user_callback;
static void runcom_callback(void *, struct kevent *);
static kq_callback kqruncom_callback = runcom_callback;

static void single_user(void);
static void runcom(void);

static bool runcom_safe = false;
static bool runcom_netboot = false;
static bool single_user_mode = false;
static bool run_runcom = true;
static pid_t single_user_pid = 0;
static pid_t runcom_pid = 0;

static void setctty(const char *, int);

// gvdl@next.com 14 Aug 1995
//   - from ~apps/loginwindow_proj/loginwindow/common.h
#define REALLY_EXIT_TO_CONSOLE                  229

// From old init.c
// These flags are used in the se_flags field of the init_session structure
#define SE_SHUTDOWN     0x1             /* session won't be restarted */

// The flags below control what sort of getty is launched.
#define SE_GETTY_LAUNCH 0x30    /* What type of getty to launch */ 
#define SE_COMMON       0x00    /* Usual command that is run - getty */
#define SE_ONERROR      0x10    /* Command to run if error condition occurs.
                                 * This will almost always be the windowserver
                                 * and loginwindow.  This is so if the w.s.
                                 * ever dies, that the naive user (stan)
                                 * doesn't ever see the console window. */
#define SE_ONOPTION     0x20    /* Command to run when loginwindow exits with
                                 * special error code (229).  This signifies
                                 * that the user typed "console" at l.w. and
                                 * l.w. wants to exit and have init run getty
                                 * which will then put up a console window. */

typedef struct _se_command {
        char    *path;          /* what to run on that port */
        char    **argv;         /* pre-parsed argument array */
} se_cmd_t;

typedef struct init_session {
        kq_callback se_callback;        /* run loop callback */
        int     se_index;               /* index of entry in ttys file */
        pid_t   se_process;             /* controlling process */
        time_t  se_started;             /* used to avoid thrashing */
        int     se_flags;               /* status of session */
        char    *se_device;             /* filename of port */
        se_cmd_t se_getty;              /* what to run on that port */
        se_cmd_t se_onerror;            /* See SE_ONERROR above */
        se_cmd_t se_onoption;           /* See SE_ONOPTION above */
        TAILQ_ENTRY(init_session) tqe;
} *session_t;

static TAILQ_HEAD(sessionshead, init_session) sessions = TAILQ_HEAD_INITIALIZER(sessions);

static void session_new(int, struct ttyent *);
static void session_free(session_t);
static void session_launch(session_t);
static void session_reap(session_t);
static void session_callback(void *, struct kevent *);

static char **construct_argv(char *);
static void setsecuritylevel(int);
static int getsecuritylevel(void);
static int setupargv(session_t, struct ttyent *);
static bool should_fsck(void);

void
init_boot(bool sflag)
{
        int nbmib[2] = { CTL_KERN, KERN_NETBOOT };
        int sbmib[2] = { CTL_KERN, KERN_SAFEBOOT };
        uint32_t v = 0;
        size_t vsz = sizeof(v);

        if (sflag) {
                single_user_mode = true;
                run_runcom = false;
        }

        if (launchd_assumes(sysctl(nbmib, 2, &v, &vsz, NULL, 0) != -1)) {
                if (v != 0)
                        runcom_netboot = true;
        }
        if (launchd_assumes(sysctl(sbmib, 2, &v, &vsz, NULL, 0) != -1)) {
                if (v != 0)
                        runcom_safe = true;
        }

}

void
init_pre_kevent(void)
{
        session_t s;

        if (single_user_pid || runcom_pid)
                return;

        if (single_user_mode)
                return single_user();

        if (run_runcom)
                return runcom();
                
        /*
         * If the administrator has not set the security level to -1
         * to indicate that the kernel should not run multiuser in secure
         * mode, and the run script has not set a higher level of security 
         * than level 1, then put the kernel into secure mode.
         */
        if (getsecuritylevel() == 0)
                setsecuritylevel(1);

        TAILQ_FOREACH(s, &sessions, tqe) {
                if (s->se_process == 0)
                        session_launch(s);
        }
}

static void
stall(char *message, ...)
{
        va_list ap;
        va_start(ap, message);

        vsyslog(LOG_ALERT, message, ap);
        va_end(ap);
        sleep(STALL_TIMEOUT);
}

static int
getsecuritylevel(void)
{
        int name[2], curlevel;
        size_t len;

        name[0] = CTL_KERN;
        name[1] = KERN_SECURELVL;
        len = sizeof (curlevel);
        if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
                syslog(LOG_ALERT, "cannot get kernel security level: %m");
                return -1;
        }
        return curlevel;
}

static void
setsecuritylevel(int newlevel)
{
        int name[2], curlevel;

        curlevel = getsecuritylevel();
        if (newlevel == curlevel)
                return;
        name[0] = CTL_KERN;
        name[1] = KERN_SECURELVL;
        if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) {
                syslog(LOG_ALERT, "cannot change kernel security level from %d to %d: %m",
                                curlevel, newlevel);
                return;
        }
        syslog(LOG_INFO, "kernel security level changed from %d to %d",
            curlevel, newlevel);
}

/*
 * Start a session and allocate a controlling terminal.
 * Only called by children of init after forking.
 */
static void
setctty(const char *name, int flags)
{
        int fd;

        revoke(name);
        if ((fd = open(name, flags | O_RDWR)) == -1) {
                stall("can't open %s: %m", name);
                exit(EXIT_FAILURE);
        }
        if (login_tty(fd) == -1) {
                stall("can't get %s for controlling terminal: %m", name);
                exit(EXIT_FAILURE);
        }
}

static void
single_user(void)
{
        bool runcom_fsck = should_fsck();
        char *argv[2];

        if (getsecuritylevel() > 0)
                setsecuritylevel(0);

        if ((single_user_pid = launchd_fork()) == -1) {
                syslog(LOG_ERR, "can't fork single-user shell, trying again: %m");
                return;
        } else if (single_user_pid == 0) {
                setctty(_PATH_CONSOLE, O_POPUP);

                setenv("TERM", "vt100", 1);
                setenv("SafeBoot", runcom_safe ? "-x" : "", 1);
                setenv("VerboseFlag", "-v", 1); /* single user mode implies verbose mode */
                setenv("FsckSlash", runcom_fsck ? "-F" : "", 1);
                setenv("NetBoot", runcom_netboot ? "-N" : "", 1);

                if (runcom_fsck) {
                        fprintf(stdout, "Singleuser boot -- fsck not done\n");
                        fprintf(stdout, "Root device is mounted read-only\n\n");
                        fprintf(stdout, "If you want to make modifications to files:\n");
                        fprintf(stdout, "\t/sbin/fsck -fy\n\t/sbin/mount -uw /\n\n");
                        fprintf(stdout, "If you wish to boot the system:\n");
                        fprintf(stdout, "\texit\n\n");
                        fflush(stdout);
                }

                argv[0] = "-sh";
                argv[1] = NULL;
                execv(_PATH_BSHELL, argv);
                syslog(LOG_ERR, "can't exec %s for single user: %m", _PATH_BSHELL);
                sleep(STALL_TIMEOUT);
                exit(EXIT_FAILURE);
        } else {
                if (kevent_mod(single_user_pid, EVFILT_PROC, EV_ADD, 
                                        NOTE_EXIT, 0, &kqsingle_user_callback) == -1)
                        single_user_callback(NULL, NULL);
        }
}

static void
single_user_callback(void *obj __attribute__((unused)), struct kevent *kev __attribute__((unused)))
{
        int status;

        if (!launchd_assumes(waitpid(single_user_pid, &status, 0) == single_user_pid))
                return;

        if (WIFEXITED(status) && WEXITSTATUS(status) == EXIT_SUCCESS) {
                syslog(LOG_INFO, "single user shell terminated, restarting");
                run_runcom = true;
                single_user_mode = false;
        } else {
                syslog(LOG_INFO, "single user shell terminated.");
                run_runcom = false;
                if (WTERMSIG(status) != SIGKILL)
                        single_user_mode = true;
        }

        single_user_pid = 0;
}

static struct timeval runcom_start_tv = { 0, 0 };
/*
 * Run the system startup script.
 */
static void
runcom(void)
{
        bool runcom_fsck = should_fsck();
        char *argv[] = { "/bin/launchctl", "bootstrap", NULL };
        struct termios term;
        int vdisable;

        gettimeofday(&runcom_start_tv, NULL);

        if ((runcom_pid = launchd_fork()) == -1) {
                syslog(LOG_ERR, "can't fork for %s on %s: %m", _PATH_BSHELL, _PATH_RUNCOM);
                sleep(STALL_TIMEOUT);
                runcom_pid = 0;
                single_user_mode = true;
                return;
        } else if (runcom_pid > 0) {
                run_runcom = false;
                if (kevent_mod(runcom_pid, EVFILT_PROC, EV_ADD, 
                                        NOTE_EXIT, 0, &kqruncom_callback) == -1) {
                        runcom_callback(NULL, NULL);
                }
                return;
        }

        setctty(_PATH_CONSOLE, 0);

        if ((vdisable = fpathconf(STDIN_FILENO, _PC_VDISABLE)) == -1) {
                syslog(LOG_WARNING, "fpathconf(\"%s\") %m", _PATH_CONSOLE);
        } else if (tcgetattr(STDIN_FILENO, &term) == -1) {
                syslog(LOG_WARNING, "tcgetattr(\"%s\") %m", _PATH_CONSOLE);
        } else {
                term.c_cc[VINTR] = vdisable;
                term.c_cc[VKILL] = vdisable;
                term.c_cc[VQUIT] = vdisable;
                term.c_cc[VSUSP] = vdisable;
                term.c_cc[VSTART] = vdisable;
                term.c_cc[VSTOP] = vdisable;
                term.c_cc[VDSUSP] = vdisable;

                if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &term) == -1)
                        syslog(LOG_WARNING, "tcsetattr(\"%s\") %m", _PATH_CONSOLE);
        }

        setenv("SafeBoot", runcom_safe ? "-x" : "", 1);
        setenv("FsckSlash", runcom_fsck ? "-F" : "", 1);
        setenv("NetBoot", runcom_netboot ? "-N" : "", 1);

        execv(argv[0], argv);
        stall("can't exec %s for %s: %m", _PATH_BSHELL, _PATH_RUNCOM);
        exit(EXIT_FAILURE);
}

static void
runcom_callback(void *obj __attribute__((unused)), struct kevent *kev __attribute__((unused)))
{
        int status;
        struct timeval runcom_end_tv, runcom_total_tv;
        double sec;

        gettimeofday(&runcom_end_tv, NULL);
        timersub(&runcom_end_tv, &runcom_start_tv, &runcom_total_tv);
        sec = runcom_total_tv.tv_sec;
        sec += (double)runcom_total_tv.tv_usec / (double)1000000;
        syslog(LOG_INFO, "%s finished in: %.3f seconds", _PATH_RUNCOM, sec);

        if (launchd_assumes(waitpid(runcom_pid, &status, 0) == runcom_pid)) {
                runcom_pid = 0;
        } else {
                syslog(LOG_ERR, "going to single user mode");
                single_user_mode = true;
                return;
        }

        if (WIFEXITED(status) && WEXITSTATUS(status) == EXIT_SUCCESS) {
                logwtmp("~", "reboot", "");
                return;
        } else if (WIFSIGNALED(status) && (WTERMSIG(status) == SIGTERM || WTERMSIG(status) == SIGKILL)) {
                return;
        }

        syslog(LOG_ERR, "%s on %s terminated abnormally, going to single user mode",
                        _PATH_BSHELL, _PATH_RUNCOM);
        single_user_mode = true;
}

/*
 * Construct an argument vector from a command line.
 */
char **
construct_argv(command)
        char *command;
{
        int argc = 0;
        char **argv = (char **) malloc(((strlen(command) + 1) / 2 + 1)
                                                * sizeof (char *));
        static const char separators[] = " \t";

        if ((argv[argc++] = strtok(command, separators)) == 0)
                return 0;
        while ((argv[argc++] = strtok(NULL, separators)))
                continue;
        return argv;
}

/*
 * Deallocate a session descriptor.
 */

static void free_command(se_cmd_t *se_cmd)
{
    if (se_cmd->path) {
        free(se_cmd->path);
        free(se_cmd->argv);
    }
}

void
session_free(session_t s)
{
        TAILQ_REMOVE(&sessions, s, tqe);
        if (s->se_process) {
                if (kevent_mod(s->se_process, EVFILT_PROC, EV_ADD, 
                                        NOTE_EXIT, 0, &kqsimple_zombie_reaper) == -1)
                        session_reap(s);
                else
                        kill(s->se_process, SIGHUP);
        }
        free(s->se_device);
        free_command(&s->se_getty);
        free_command(&s->se_onerror);
        free_command(&s->se_onoption);
        free(s);
}

static int setup_command(se_cmd_t *se_cmd, char *command, char *arg )
{
        char *commandWithArg;

        asprintf(&commandWithArg, "%s %s", command, arg);

        free_command(se_cmd);

        se_cmd->path = commandWithArg;
        se_cmd->argv = construct_argv(commandWithArg);
        if (se_cmd->argv == NULL) {
                free(se_cmd->path);
                se_cmd->path = NULL;
                return 0;
        }
        return 1;
}

/*
 * Calculate getty and if useful window argv vectors.
 */
static int
setupargv(sp, typ)
        session_t sp;
        struct ttyent *typ;
{
    char *type;

    if ( !setup_command(&sp->se_getty, typ->ty_getty, typ->ty_name) )
    {
        type = "getty";
        goto bad_args;
    }

    if (typ->ty_onerror
    && !setup_command(&sp->se_onerror, typ->ty_onerror, typ->ty_name) )
    {
        type = "onerror";
        goto bad_args;
    }

    if (typ->ty_onoption
    && !setup_command(&sp->se_onoption, typ->ty_onoption, typ->ty_name) )
    {
        type = "onoption";
        goto bad_args;
    }

    return 1;

bad_args:
    syslog(LOG_WARNING, "can't parse %s for port %s", type, sp->se_device);
    return 0;
}


/*
 * Allocate a new session descriptor.
 */
void
session_new(session_index, typ)
        int session_index;
        struct ttyent *typ;
{
        session_t s;

        if ((typ->ty_status & TTY_ON) == 0 ||
            typ->ty_name == 0 ||
            typ->ty_getty == 0)
                return;

        s = calloc(1, sizeof(struct init_session));

        s->se_callback = session_callback;
        s->se_index = session_index;

        TAILQ_INSERT_TAIL(&sessions, s, tqe);

        asprintf(&s->se_device, "%s%s", _PATH_DEV, typ->ty_name);

        if (setupargv(s, typ) == 0)
                session_free(s);
}

static void
session_launch(session_t s)
{
        pid_t pid;
        sigset_t mask;
        se_cmd_t *se_cmd;
        const char *session_type = NULL;
        time_t current_time      = time(NULL);
        bool is_loginwindow = false;

        // Setup the default values;
        switch (s->se_flags & SE_GETTY_LAUNCH) {
        case SE_ONOPTION:
                if (s->se_onoption.path) {
                        se_cmd       = &s->se_onoption;
                        session_type = "onoption";
                        break;
                }
                /* No break */
        case SE_ONERROR:
                if (s->se_onerror.path) {
                        se_cmd       = &s->se_onerror;
                        session_type = "onerror";
                        break;
                }
                /* No break */
        case SE_COMMON:
        default:
                se_cmd       = &s->se_getty;
                session_type = "getty";
                break;
        }

        if (strcmp(se_cmd->argv[0], "/System/Library/CoreServices/loginwindow.app/Contents/MacOS/loginwindow") == 0)
                is_loginwindow = true;

        pid = launchd_fork();

        if (pid == -1) {
                syslog(LOG_ERR, "can't fork for %s on port %s: %m",
                                session_type, s->se_device);
                return;
        }

        if (pid) {
                s->se_process = pid;
                s->se_started = time(NULL);
                s->se_flags  &= ~SE_GETTY_LAUNCH; // clear down getty launch type
                if (kevent_mod(pid, EVFILT_PROC, EV_ADD, NOTE_EXIT, 0, &s->se_callback) == -1)
                        session_reap(s);
                return;
        }

        if (current_time > s->se_started &&
            current_time - s->se_started < GETTY_SPACING) {
                syslog(LOG_WARNING, "%s repeating too quickly on port %s, sleeping",
                        session_type, s->se_device);
                sleep(GETTY_SLEEP);
        }

        sigemptyset(&mask);
        sigprocmask(SIG_SETMASK, &mask, NULL);


        if (!is_loginwindow)
                launchd_SessionCreate();

        execv(se_cmd->argv[0], se_cmd->argv);
        stall("can't exec %s '%s' for port %s: %m", session_type,
                se_cmd->argv[0], s->se_device);
        exit(EXIT_FAILURE);
}

static void
session_callback(void *obj, struct kevent *kev __attribute__((unused)))
{
        session_t s = obj;

        session_reap(s);
        if (s->se_flags & SE_SHUTDOWN) {
                session_free(s);
        } else {
                session_launch(s);
        }
}

static void
session_reap(session_t s)
{
        char *line;
        int status;

        if (!launchd_assumes(waitpid(s->se_process, &status, 0) == s->se_process))
                return;

        if (WIFSIGNALED(status)) {
                syslog(LOG_WARNING, "%s port %s exited abnormally: %s",
                                s->se_getty.path, s->se_device, strsignal(WTERMSIG(status)));
                s->se_flags |= SE_ONERROR; 
        } else if (WEXITSTATUS(status) == REALLY_EXIT_TO_CONSOLE) {
                /* WIFEXITED(status) assumed */
                s->se_flags |= SE_ONOPTION;
        } else {
                s->se_flags |= SE_ONERROR;
        }

        s->se_process = 0;
        line = s->se_device + sizeof(_PATH_DEV) - 1;

        if (logout(line))
                logwtmp(line, "", "");
}

/*
 * This is an n-squared algorithm.  We hope it isn't run often...
 */
void
update_ttys(void)
{
        session_t sp;
        struct ttyent *typ;
        int session_index = 0;
        int devlen;

        devlen = sizeof(_PATH_DEV) - 1;
        while ((typ = getttyent())) {
                ++session_index;

                TAILQ_FOREACH(sp, &sessions, tqe) {
                        if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
                                break;
                }

                if (sp == NULL) {
                        session_new(session_index, typ);
                        continue;
                }

                if (sp->se_index != session_index) {
                        syslog(LOG_INFO, "port %s changed utmp index from %d to %d",
                               sp->se_device, sp->se_index,
                               session_index);
                        sp->se_index = session_index;
                }

                if ((typ->ty_status & TTY_ON) == 0 ||
                    typ->ty_getty == 0) {
                        session_free(sp);
                        continue;
                }

                sp->se_flags &= ~SE_SHUTDOWN;

                if (setupargv(sp, typ) == 0) {
                        syslog(LOG_WARNING, "can't parse getty for port %s",
                                sp->se_device);
                        session_free(sp);
                }
        }

        endttyent();
}

/*
 * Block further logins.
 */
void
catatonia(void)
{
        session_t s;

        TAILQ_FOREACH(s, &sessions, tqe)
                s->se_flags |= SE_SHUTDOWN;
}

bool init_check_pid(pid_t p)
{
        session_t s;

        TAILQ_FOREACH(s, &sessions, tqe) {
                if (s->se_process == p)
                        return true;
        }

        if (single_user_pid == p)
                return true;

        if (runcom_pid == p)
                return true;

        return false;
}

bool
should_fsck(void)
{
        struct statfs sfs;
        bool r = true;

        if (launchd_assumes(statfs("/", &sfs) != -1)) {
                if (!(sfs.f_flags & MNT_RDONLY)) {
                        r = false;
                }
        }
        
        return r;
}