svc/startd/fork.c

	fork.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

/*
 * fork.c - safe forking for svc.startd
 *
 * fork_configd() and fork_sulogin() are related, special cases that handle the
 * spawning of specific client processes for svc.startd.
 */

#include <sys/contract/process.h>
#include <sys/corectl.h>
#include <sys/ctfs.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <sys/wait.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <libcontract.h>
#include <libcontract_priv.h>
#include <limits.h>
#include <port.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "configd_exit.h"
#include "protocol.h"
#include "startd.h"

pid_t
startd_fork1(int *forkerr)
{
    pid_t p;

    /*
     * prefork stack
     */
    wait_prefork();

    p = fork1();

    if (p == -1 && forkerr != NULL)
        *forkerr = errno;

    /*
     * postfork stack
     */
    wait_postfork(p);

    return (p);
}

/*
 * void fork_mount(char *, char *)
 *   Run mount(1M) with the given options and mount point.  (mount(1M) has much
 *   hidden knowledge; it's much less correct to reimplement that logic here to
 *   save a fork(2)/exec(2) invocation.)
 */
int
fork_mount(char *path, char *opts)
{
    pid_t pid;
    uint_t tries = 0;
    int status;

    for (pid = fork1(); pid == -1; pid = fork1()) {
        if (++tries > MAX_MOUNT_RETRIES)
            return (-1);

        (void) sleep(tries);
    }

    if (pid != 0) {
        (void) waitpid(pid, &status, 0);

        /*
         * If our mount(1M) invocation exited by peculiar means, or with
         * a non-zero status, our mount likelihood is low.
         */
        if (!WIFEXITED(status) ||
            WEXITSTATUS(status) != 0)
            return (-1);

        return (0);
    }

    (void) execl("/sbin/mount", "mount", "-o", opts, path, NULL);

    return (-1);
}

/*
 * pid_t fork_common(...)
 *   Common routine used by fork_sulogin and fork_configd to fork a
 *   process in a contract with the provided terms.  Invokes
 *   fork_sulogin (with its no-fork argument set) on errors.
 */
static pid_t
fork_common(const char *name, int retries, ctid_t *ctidp,
    uint_t inf, uint_t crit, uint_t fatal, uint_t param, uint64_t cookie)
{
    uint_t tries = 0;
    int ctfd, err;
    pid_t pid;

    /*
     * Establish process contract terms.
     */
    if ((ctfd = open64(CTFS_ROOT "/process/template", O_RDWR)) == -1) {
        fork_sulogin(B_TRUE, "Could not open process contract template "
            "for %s: %s\n", name, strerror(errno));
        /* NOTREACHED */
    }

    err = ct_tmpl_set_critical(ctfd, crit);
    err |= ct_pr_tmpl_set_fatal(ctfd, fatal);
    err |= ct_tmpl_set_informative(ctfd, inf);
    err |= ct_pr_tmpl_set_param(ctfd, param);
    err |= ct_tmpl_set_cookie(ctfd, cookie);
    if (err) {
        (void) close(ctfd);
        fork_sulogin(B_TRUE, "Could not set %s process contract "
            "terms\n", name);
        /* NOTREACHED */
    }

    if (err = ct_tmpl_activate(ctfd)) {
        (void) close(ctfd);
        fork_sulogin(B_TRUE, "Could not activate %s process contract "
            "template: %s\n", name, strerror(err));
        /* NOTREACHED */
    }

    /*
     * Attempt to fork "retries" times.
     */
    for (pid = fork1(); pid == -1; pid = fork1()) {
        if (++tries > retries) {
            /*
             * When we exit the sulogin session, init(1M)
             * will restart svc.startd(1M).
             */
            err = errno;
            (void) ct_tmpl_clear(ctfd);
            (void) close(ctfd);
            fork_sulogin(B_TRUE, "Could not fork to start %s: %s\n",
                name, strerror(err));
            /* NOTREACHED */
        }
        (void) sleep(tries);
    }

    /*
     * Clean up, return pid and ctid.
     */
    if (pid != 0 && (errno = contract_latest(ctidp)) != 0)
        uu_die("Could not get new contract id for %s\n", name);
    (void) ct_tmpl_clear(ctfd);
    (void) close(ctfd);

    return (pid);
}

/*
 * void fork_sulogin(boolean_t, const char *, ...)
 *   When we are invoked with the -s flag from boot (or run into an unfixable
 *   situation), we run a private copy of sulogin.  When the sulogin session
 *   is ended, we continue.  This is the last fallback action for system
 *   maintenance.
 *
 *   If immediate is true, fork_sulogin() executes sulogin(1M) directly, without
 *   forking.
 *
 *   Because fork_sulogin() is needed potentially before we daemonize, we leave
 *   it outside the wait_register() framework.
 */
/*PRINTFLIKE2*/
void
fork_sulogin(boolean_t immediate, const char *format, ...)
{
    va_list args;
    int i, fd_console;

    (void) printf("Requesting System Maintenance Mode\n");

    if (!booting_to_single_user)
        (void) printf("(See /lib/svc/share/README for more "
            "information.)\n");

    va_start(args, format);
    (void) vprintf(format, args);
    va_end(args);

    if (!immediate) {
        ctid_t  ctid;
        pid_t   pid;

        pid = fork_common("sulogin", MAX_SULOGIN_RETRIES, &ctid,
            CT_PR_EV_HWERR, 0, CT_PR_EV_HWERR, CT_PR_PGRPONLY,
            SULOGIN_COOKIE);

        if (pid != 0) {
            (void) waitpid(pid, NULL, 0);
            contract_abandon(ctid);
            return;
        }
        /* close all inherited fds */
        closefrom(0);
    } else {
        (void) printf("Directly executing sulogin.\n");
        /*
         * Can't call closefrom() in this MT section
         * so safely close a minimum set of fds.
         */
        for (i = 0; i < 3; i++)
            (void) close(i);
    }

    (void) setpgrp();

    /* open the console for sulogin */
    if ((fd_console = open("/dev/console", O_RDWR)) >= 0) {
        if (fd_console != STDIN_FILENO)
            while (dup2(fd_console, STDIN_FILENO) < 0 &&
                errno == EINTR)
                ;
        if (fd_console != STDOUT_FILENO)
            while (dup2(fd_console, STDOUT_FILENO) < 0 &&
                errno == EINTR)
                ;
        if (fd_console != STDERR_FILENO)
            while (dup2(fd_console, STDERR_FILENO) < 0 &&
                errno == EINTR)
                ;
        if (fd_console > 2)
            (void) close(fd_console);
    }

    (void) execl("/sbin/sulogin", "sulogin", NULL);

    uu_warn("Could not exec() sulogin");

    exit(1);
}

#define CONFIGD_PATH    "/lib/svc/bin/svc.configd"

/*
 * void fork_configd(int status)
 *   We are interested in exit events (since the parent's exiting means configd
 *   is ready to run and since the child's exiting indicates an error case) and
 *   in empty events.  This means we have a unique template for initiating
 *   configd.
 */
/*ARGSUSED*/
void
fork_configd(int exitstatus)
{
    pid_t pid;
    ctid_t ctid = -1;
    int err;
    char path[PATH_MAX];

retry:
    log_framework(LOG_DEBUG, "fork_configd trying to start svc.configd\n");

    /*
     * If we're retrying, we will have an old contract lying around
     * from the failure.  Since we're going to be creating a new
     * contract shortly, we abandon the old one now.
     */
    if (ctid != -1)
        contract_abandon(ctid);
    ctid = -1;

    pid = fork_common("svc.configd", MAX_CONFIGD_RETRIES, &ctid,
        0, CT_PR_EV_EXIT, 0, CT_PR_INHERIT | CT_PR_REGENT, CONFIGD_COOKIE);

    if (pid != 0) {
        int exitstatus;

        st->st_configd_pid = pid;

        if (waitpid(pid, &exitstatus, 0) == -1) {
            fork_sulogin(B_FALSE, "waitpid on svc.configd "
                "failed: %s\n", strerror(errno));
        } else if (WIFEXITED(exitstatus)) {
            char *errstr;

            /*
             * Examine exitstatus.  This will eventually get more
             * complicated, as we will want to teach startd how to
             * invoke configd with alternate repositories, etc.
             *
             * Note that exec(2) failure results in an exit status
             * of 1, resulting in the default clause below.
             */

            /*
             * Assign readable strings to cases we don't handle, or
             * have error outcomes that cannot be eliminated.
             */
            switch (WEXITSTATUS(exitstatus)) {
            case CONFIGD_EXIT_BAD_ARGS:
                errstr = "bad arguments";
                break;

            case CONFIGD_EXIT_DATABASE_BAD:
                errstr = "database corrupt";
                break;

            case CONFIGD_EXIT_DATABASE_LOCKED:
                errstr = "database locked";
                break;
            case CONFIGD_EXIT_INIT_FAILED:
                errstr = "initialization failure";
                break;
            case CONFIGD_EXIT_DOOR_INIT_FAILED:
                errstr = "door initialization failure";
                break;
            case CONFIGD_EXIT_DATABASE_INIT_FAILED:
                errstr = "database initialization failure";
                break;
            case CONFIGD_EXIT_NO_THREADS:
                errstr = "no threads available";
                break;
            case CONFIGD_EXIT_LOST_MAIN_DOOR:
                errstr = "lost door server attachment";
                break;
            case 1:
                errstr = "execution failure";
                break;
            default:
                errstr = "unknown error";
                break;
            }

            /*
             * Remedial actions for various configd failures.
             */
            switch (WEXITSTATUS(exitstatus)) {
            case CONFIGD_EXIT_OKAY:
                break;

            case CONFIGD_EXIT_DATABASE_LOCKED:
                /* attempt remount of / read-write */
                if (fs_is_read_only("/", NULL) == 1) {
                    if (fs_remount("/") == -1)
                        fork_sulogin(B_FALSE,
                            "remount of root "
                            "filesystem failed\n");

                    goto retry;
                }
                break;

            default:
                fork_sulogin(B_FALSE, "svc.configd exited "
                    "with status %d (%s)\n",
                    WEXITSTATUS(exitstatus), errstr);
                goto retry;
            }
        } else if (WIFSIGNALED(exitstatus)) {
            char signame[SIG2STR_MAX];

            if (sig2str(WTERMSIG(exitstatus), signame))
                (void) snprintf(signame, SIG2STR_MAX,
                    "signum %d", WTERMSIG(exitstatus));

            fork_sulogin(B_FALSE, "svc.configd signalled:"
                " %s\n", signame);

            goto retry;
        } else {
            fork_sulogin(B_FALSE, "svc.configd non-exit "
                "condition: 0x%x\n", exitstatus);

            goto retry;
        }

        /*
         * Announce that we have a valid svc.configd status.
         */
        MUTEX_LOCK(&st->st_configd_live_lock);
        st->st_configd_lives = 1;
        err = pthread_cond_broadcast(&st->st_configd_live_cv);
        assert(err == 0);
        MUTEX_UNLOCK(&st->st_configd_live_lock);

        log_framework(LOG_DEBUG, "fork_configd broadcasts configd is "
            "live\n");
        return;
    }

    /*
     * Set our per-process core file path to leave core files in
     * /etc/svc/volatile directory, named after the PID to aid in debugging.
     */
    (void) snprintf(path, sizeof (path),
        "/etc/svc/volatile/core.configd.%%p");

    (void) core_set_process_path(path, strlen(path) + 1, getpid());

    log_framework(LOG_DEBUG, "executing svc.configd\n");

    (void) execl(CONFIGD_PATH, CONFIGD_PATH, NULL);

    /*
     * Status code is used above to identify configd exec failure.
     */
    exit(1);
}

void *
fork_configd_thread(void *vctid)
{
    int fd, err;
    ctid_t configd_ctid = (ctid_t)vctid;

    if (configd_ctid == -1) {
        log_framework(LOG_DEBUG,
            "fork_configd_thread starting svc.configd\n");
        fork_configd(0);
    } else {
        /*
         * configd_ctid is known:  we broadcast and continue.
         * test contract for appropriate state by verifying that
         * there is one or more processes within it?
         */
        log_framework(LOG_DEBUG,
            "fork_configd_thread accepting svc.configd with CTID %ld\n",
            configd_ctid);
        MUTEX_LOCK(&st->st_configd_live_lock);
        st->st_configd_lives = 1;
        (void) pthread_cond_broadcast(&st->st_configd_live_cv);
        MUTEX_UNLOCK(&st->st_configd_live_lock);
    }

    fd = open64(CTFS_ROOT "/process/pbundle", O_RDONLY);
    if (fd == -1)
        uu_die("process bundle open failed");

    /*
     * Make sure we get all events (including those generated by configd
     * before this thread was started).
     */
    err = ct_event_reset(fd);
    assert(err == 0);

    for (;;) {
        int efd, sfd;
        ct_evthdl_t ev;
        uint32_t type;
        ctevid_t evid;
        ct_stathdl_t status;
        ctid_t ctid;
        uint64_t cookie;
        pid_t pid;

        if (err = ct_event_read_critical(fd, &ev)) {
            assert(err != EINVAL && err != EAGAIN);
            log_error(LOG_WARNING,
                "Error reading next contract event: %s",
                strerror(err));
            continue;
        }

        evid = ct_event_get_evid(ev);
        ctid = ct_event_get_ctid(ev);
        type = ct_event_get_type(ev);

        /* Fetch cookie. */
        sfd = contract_open(ctid, "process", "status", O_RDONLY);
        if (sfd < 0) {
            ct_event_free(ev);
            continue;
        }

        if (err = ct_status_read(sfd, CTD_COMMON, &status)) {
            log_framework(LOG_WARNING, "Could not get status for "
                "contract %ld: %s\n", ctid, strerror(err));

            ct_event_free(ev);
            startd_close(sfd);
            continue;
        }

        cookie = ct_status_get_cookie(status);

        ct_status_free(status);

        startd_close(sfd);

        /*
         * Don't process events from contracts we aren't interested in.
         */
        if (cookie != CONFIGD_COOKIE) {
            ct_event_free(ev);
            continue;
        }

        if (type == CT_PR_EV_EXIT) {
            int exitstatus;

            (void) ct_pr_event_get_pid(ev, &pid);
            (void) ct_pr_event_get_exitstatus(ev,
                &exitstatus);

            if (st->st_configd_pid != pid) {
                /*
                 * This is the child exiting, so we
                 * abandon the contract and restart
                 * configd.
                 */
                contract_abandon(ctid);
                fork_configd(exitstatus);
            }
        }

        efd = contract_open(ctid, "process", "ctl", O_WRONLY);
        if (efd != -1) {
            (void) ct_ctl_ack(efd, evid);
            startd_close(efd);
        }

        ct_event_free(ev);

    }

    /*NOTREACHED*/
    return (NULL);
}

void
fork_rc_script(char rl, const char *arg, boolean_t wait)
{
    pid_t pid;
    int tmpl, err, stat;
    char path[20] = "/sbin/rc.", log[20] = "rc..log", timebuf[20];
    time_t now;
    struct tm ltime;
    size_t sz;
    char *pathenv;
    char **nenv;

    path[8] = rl;

    tmpl = open64(CTFS_ROOT "/process/template", O_RDWR);
    if (tmpl >= 0) {
        err = ct_tmpl_set_critical(tmpl, 0);
        assert(err == 0);

        err = ct_tmpl_set_informative(tmpl, 0);
        assert(err == 0);

        err = ct_pr_tmpl_set_fatal(tmpl, 0);
        assert(err == 0);

        err = ct_tmpl_activate(tmpl);
        assert(err == 0);

        err = close(tmpl);
        assert(err == 0);
    } else {
        uu_warn("Could not create contract template for %s.\n", path);
    }

    pid = startd_fork1(NULL);
    if (pid < 0) {
        return;
    } else if (pid != 0) {
        /* parent */
        if (wait) {
            do
                err = waitpid(pid, &stat, 0);
            while (err != 0 && errno == EINTR);

            if (!WIFEXITED(stat)) {
                log_framework(LOG_INFO,
                    "%s terminated with waitpid() status %d.\n",
                    path, stat);
            } else if (WEXITSTATUS(stat) != 0) {
                log_framework(LOG_INFO,
                    "%s failed with status %d.\n", path,
                    WEXITSTATUS(stat));
            }
        }

        return;
    }

    /* child */

    log[2] = rl;

    setlog(log);

    now = time(NULL);
    sz = strftime(timebuf, sizeof (timebuf), "%b %e %T",
        localtime_r(&now, &ltime));
    assert(sz != 0);

    (void) fprintf(stderr, "%s Executing %s %s\n", timebuf, path, arg);

    if (rl == 'S')
        pathenv = "PATH=/sbin:/usr/sbin:/usr/bin";
    else
        pathenv = "PATH=/usr/sbin:/usr/bin";

    nenv = set_smf_env(NULL, 0, pathenv, NULL, NULL);

    (void) execle(path, path, arg, 0, nenv);

    perror("exec");
    exit(0);
}