init.c

linux 安装程序

        snprintf(devname, 63, "/dev/%s", devnodes[i].devname);
        switch (devnodes[i].type) {
        case DIRTYPE:
            if (mkdir(devname, devnodes[i].perms) < 0) {
                fprintf(stderr, "Unable to create directory %s: %s\n", 
                        devname, strerror(errno));
            }
            break;
        case CHARDEV:
            type = S_IFCHR;
            break;
        case BLOCKDEV:
            type = S_IFBLK;
            break;
        }
        if (type == -1) continue;

        if (mknod(devname, type | devnodes[i].perms, 
                  makedev(devnodes[i].major, devnodes[i].minor)) < 0)
            fprintf(stderr, "Unable to create device %s: %s\n", devname, 
                    strerror(errno));
    }
}

static void termReset(void) {
    /* change to tty1 */
    ioctl(0, VT_ACTIVATE, 1);
    /* reset terminal */
    tcsetattr(0, TCSANOW, &ts);
    /* Shift in, default color, move down 100 lines */
    /* ^O        ^[[0m          ^[[100E */
    printf("\017\033[0m\033[100E\n");
}

/* reboot handler */
static void sigintHandler(int signum) {
    termReset();
    shutDown(getNoKill(), 1, 0);
}

/* halt handler */
static void sigUsr1Handler(int signum) {
    termReset();
    shutDown(getNoKill(), 0, 0);
}

/* poweroff handler */
static void sigUsr2Handler(int signum) {
    termReset();
    shutDown(getNoKill(), 0, 1);
}

static int getNoKill(void) {
    int fd;
    int len;
    char buf[1024];

    /* look through /proc/cmdline for special options */
    if ((fd = open("/proc/cmdline", O_RDONLY,0)) > 0) {
        len = read(fd, buf, sizeof(buf) - 1);
        close(fd);
        if (len > 0 && mystrstr(buf, "nokill"))
            return 1;
    }
    return 0;
}

static int getInitPid(void) {
    int fd = 0, pid = -1, ret;
    char * buf = calloc(1, 10);

    fd = open("/var/run/init.pid", O_RDONLY);
    if (fd < 0) {
        fprintf(stderr, "Unable to find pid of init!!!\n");
        return -1;
    }
    ret = read(fd, buf, 9);
    close(fd);
    ret = sscanf(buf, "%d", &pid);
    return pid;
}

int main(int argc, char **argv) {
    pid_t installpid, childpid;
    int waitStatus;
    int fd = -1;
    int doReboot = 0;
    int doShutdown =0;
    int isSerial = 0;
    char * console = NULL;
    int noKill = 0;
    char * argvc[15];
    char ** argvp = argvc;
    char twelve = 12;
    struct serial_struct si;
    int i, disable_keys;

    if (!strncmp(basename(argv[0]), "poweroff", 8)) {
        printf("Running poweroff...\n");
        fd = getInitPid();
        if (fd > 0)
            kill(fd, SIGUSR2);
        exit(0);
    } else if (!strncmp(basename(argv[0]), "halt", 4)) {
        printf("Running halt...\n");
        fd = getInitPid();
        if (fd > 0)
            kill(fd, SIGUSR1);
        exit(0);
    } else if (!strncmp(basename(argv[0]), "reboot", 6)) {
        printf("Running reboot...\n");
        fd = getInitPid();
        if (fd > 0)
            kill(fd, SIGINT);
        exit(0);
    }

#if !defined(__s390__) && !defined(__s390x__)
    testing = (getppid() != 0) && (getppid() != 1);
#endif

    if (!testing) {
        /* turn off screen blanking */
        printstr("\033[9;0]");
        printstr("\033[8]");
    } else {
        printstr("(running in test mode).\n");
    }

    umask(022);

    printstr("\nGreetings.\n");

    printf("anaconda installer init version %s starting\n", VERSION);

    printf("mounting /proc filesystem... "); 
    if (!testing) {
        if (mount("/proc", "/proc", "proc", 0, NULL))
            fatal_error(1);
    }
    printf("done\n");

    printf("creating /dev filesystem... "); 
    if (!testing) {
        if (mount("/dev", "/dev", "tmpfs", 0, NULL))
            fatal_error(1);
        createDevices();
    }
    printf("done\n");

    printf("mounting /dev/pts (unix98 pty) filesystem... "); 
    if (!testing) {
        if (mount("/dev/pts", "/dev/pts", "devpts", 0, NULL))
            fatal_error(1);
    }
    printf("done\n");

    printf("mounting /sys filesystem... "); 
    if (!testing) {
        if (mount("/sys", "/sys", "sysfs", 0, NULL))
            fatal_error(1);
    }
    printf("done\n");

    /* these args are only for testing from commandline */
    for (i = 1; i < argc; i++) {
        if (!strcmp (argv[i], "serial")) {
            isSerial = 1;
            break;
        }
    }

    noKill = getNoKill();

#if !defined(__s390__) && !defined(__s390x__)
    static struct termios orig_cmode;
    struct termios cmode, mode;
    int cfd;
    
    cfd =  open("/dev/console", O_RDONLY);
    tcgetattr(cfd,&orig_cmode);
    close(cfd);

    cmode = orig_cmode;
    cmode.c_lflag &= (~ECHO);

    cfd = open("/dev/console", O_WRONLY);
    tcsetattr(cfd,TCSANOW,&cmode);
    close(cfd);

    /* handle weird consoles */
#if defined(__powerpc__)
    char * consoles[] = { "/dev/hvc0", /* hvc for JS20 */

                          "/dev/hvsi0", "/dev/hvsi1",
                          "/dev/hvsi2", /* hvsi for POWER5 */
                          NULL };
#elif defined (__ia64__)
    char * consoles[] = { "/dev/ttySG0", "/dev/xvc0", NULL };
#elif defined (__i386__) || defined (__x86_64__)
    char * consoles[] = { "/dev/xvc0", NULL };
#else
    char * consoles[] = { NULL };
#endif
    for (i = 0; consoles[i] != NULL; i++) {
        if ((fd = open(consoles[i], O_RDWR)) >= 0 && !tcgetattr(fd, &mode) && !termcmp(&cmode, &mode)) {
            printf("anaconda installer init version %s using %s as console\n",
                   VERSION, consoles[i]);
            isSerial = 3;
            console = strdup(consoles[i]);
            break;
        }
        close(fd);
    }

    cfd = open("/dev/console", O_WRONLY);
    tcsetattr(cfd,TCSANOW,&orig_cmode);
    close(cfd); 

    if ((fd < 0) && (ioctl (0, TIOCLINUX, &twelve) < 0)) {
        isSerial = 2;

        if (ioctl(0, TIOCGSERIAL, &si) == -1) {
            isSerial = 0;
        }
    }

    if (isSerial && (isSerial != 3)) {
        char *device = "/dev/ttyS0";

        printf("anaconda installer init version %s using a serial console\n", 
               VERSION);

        if (isSerial == 2)
            device = "/dev/console";
        fd = open(device, O_RDWR, 0);
        if (fd < 0)
            device = "/dev/tts/0";

        if (fd < 0) {
            printf("failed to open %s\n", device);
            fatal_error(1);
        }

        setupTerminal(fd);
    } else if (isSerial == 3) {
        setupTerminal(fd);
    } else if (fd < 0)  {
        fd = open("/dev/tty1", O_RDWR, 0);
        if (fd < 0)
            fd = open("/dev/vc/1", O_RDWR, 0);

        if (fd < 0) {
            printf("failed to open /dev/tty1 and /dev/vc/1");
            fatal_error(1);
        }
    }

    if (testing)
        exit(0);

    setsid();
    if (ioctl(0, TIOCSCTTY, NULL)) {
        printf("could not set new controlling tty\n");
    }

    dup2(fd, 0);
    dup2(fd, 1);
    dup2(fd, 2);
    if (fd > 2)
        close(fd);
#else
    dup2(0, 1);
    dup2(0, 2);
#endif

    /* disable Ctrl+Z, Ctrl+C, etc ... but not in rescue mode */
#ifdef SNAKES_ON_A_PLANE
    disable_keys = 0;
#else
    disable_keys = 1;
    if (argc > 1)
        if (mystrstr(argv[1], "rescue"))
            disable_keys = 0;
#endif

    if (disable_keys) {
        tcgetattr(0, &ts);
        ts.c_iflag &= ~BRKINT;
        ts.c_iflag |= IGNBRK;
        ts.c_iflag &= ~ISIG;
        tcsetattr(0, TCSANOW, &ts);
    }

    if (!testing) {
        int ret;
        ret = sethostname("localhost.localdomain", 21);
        /* the default domainname (as of 2.0.35) is "(none)", which confuses 
         glibc */
        ret = setdomainname("", 0);
    }

    printf("trying to remount root filesystem read write... ");
    if (mount("/", "/", "ext2", MS_REMOUNT | MS_MGC_VAL, NULL)) {
        fatal_error(1);
    }
    printf("done\n");
        
    /* we want our /tmp to be ramfs, but we also want to let people hack
     * their initrds to add things like a ks.cfg, so this has to be a little
     * tricky */
    if (!testing) {
        rename("/tmp", "/oldtmp");
        mkdir("/tmp", 0755);

        printf("mounting /tmp as ramfs... ");
        if (mount("none", "/tmp", "ramfs", 0, NULL))
            fatal_error(1);
        printf("done\n");

        copyDirectory("/oldtmp", "/tmp");
        unlink("/oldtmp");
    }

    /* Now we have some /tmp space set up, and /etc and /dev point to
       it. We should be in pretty good shape. */

    if (!testing) 
        doklog("/dev/tty4");

    /* write out a pid file */
    if ((fd = open("/var/run/init.pid", O_WRONLY|O_CREAT)) > 0) {
        char * buf = malloc(10);
        int ret;

        snprintf(buf, 9, "%d", getpid());
        ret = write(fd, buf, strlen(buf));
        close(fd);
        free(buf);
    } else {
        printf("unable to write init.pid (%d): %s\n", errno, strerror(errno));
        sleep(2);
    }

    /* Go into normal init mode - keep going, and then do a orderly shutdown
       when:

       1) /bin/install exits
       2) we receive a SIGHUP 
    */

    printf("running install...\n"); 

    setsid();

#ifdef SNAKES_ON_A_PLANE
    printf("> Snakes on a Plane <\n");

    /* hack to load core modules for debugging mode */
    char * modvc[15];
    char ** modvp = modvc;
    *modvp++ = "/bin/modprobe";
    *modvp++ = "ehci-hcd";
    *modvp++ = "uhci-hcd";
    *modvp++ = "ohci-hcd";
    *modvp++ = NULL;
    pid_t blah = fork();
    int qux;
    if (blah == 0) {
        printf("loading core debugging modules...\n");
        execve(modvc[0], modvc, env);
    } else {
        waitpid(blah, &qux, WNOHANG);
    }
#endif

    if (!(installpid = fork())) {
        /* child */
#ifdef SNAKES_ON_A_PLANE
        *argvp++ = "/bin/strace";
#endif
        *argvp++ = "/sbin/loader";

        if (isSerial == 3) {
            *argvp++ = "--virtpconsole";
            *argvp++ = console;
        }

        *argvp++ = NULL;

        printf("running %s\n", argvc[0]);
        execve(argvc[0], argvc, env);

        shutDown(1, 0, 0);
    }

    /* signal handlers for halt/poweroff */
    signal(SIGUSR1, sigUsr1Handler);
    signal(SIGUSR2, sigUsr2Handler);

    /* set up the ctrl+alt+delete handler to kill our pid, not pid 1 */
    signal(SIGINT, sigintHandler);
    if ((fd = open("/proc/sys/kernel/cad_pid", O_WRONLY)) != -1) {
        char buf[7];
        size_t count;
        sprintf(buf, "%d", getpid());
        count = write(fd, buf, strlen(buf));
        close(fd);
        /* if we succeeded in writing our pid, turn off the hard reboot
           ctrl-alt-del handler */
        if (count == strlen(buf) &&
            (fd = open("/proc/sys/kernel/ctrl-alt-del", O_WRONLY)) != -1) {
            int ret;

            ret = write(fd, "0", 1);
            close(fd);
        }
    }
    
    while (!doShutdown) {
        childpid = waitpid(-1, &waitStatus, 0);

        if (childpid == installpid) 
            doShutdown = 1;
    }

    if (!WIFEXITED(waitStatus) ||
        (WIFEXITED(waitStatus) && WEXITSTATUS(waitStatus))) {
        printf("install exited abnormally [%d/%d] ", WIFEXITED(waitStatus),
                                                     WEXITSTATUS(waitStatus));
        if (WIFSIGNALED(waitStatus)) {
            printf("-- received signal %d", WTERMSIG(waitStatus));
        }
        printf("\n");
    } else {
        doReboot = 1;
    }

    if (testing)
        exit(0);

    shutDown(noKill, doReboot, 0);

    return 0;
}

/* vim:set shiftwidth=4 softtabstop=4 ts=4: */