path: root/autojuke.c

/*
 * program "map-file" for linux autofs
 *
 * usage: /usr/sbin/automount /jukebox program /usr/sbin/autojuke
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <ctype.h>
#include <signal.h>
#include <sys/stat.h>
#include <sys/ioctl.h>

#include <asm/types.h>
#include <linux/cdrom.h>

#include "chio.h"

#define PROG     "autojuke"
#define CHANGER  "/dev/sch0"
#define CONFIG   "/etc/autojuke.conf"

#define DEBUG 0  /* set to 1 for debug output */

/* ---------------------------------------------------------------------- */

int
check_mtab(int n, char **devs)
{
    int     i,res;
    FILE   *fp;
    struct  stat st;
    char    line[79],dev[32];
    int     *fl;

    /* check for lock file */
    for (i = 0; i < 5; i++) {
	if (-1 == stat("/etc/mtab~",&st))
	    break;
	sleep(1);
    }
    if (5 == i) {
	fprintf(stderr,PROG ": /etc/mtab locked\n");
	exit(1);
    }

    if (NULL == (fp = fopen("/etc/mtab", "r"))) {
	perror(PROG ": open /etc/mtab");
	exit(1);
    }
    fl = malloc(n*sizeof(int));
    memset(fl,0,n*sizeof(int));
    while (NULL != fgets(line,79,fp)) {
	sscanf(line," %31s",dev);
	for (i = 0; i < n; i++) {
	    if (0 == strcmp(dev,devs[i]))
		fl[i] = 1;
	}
    }
    res = -1;
    for (i = 0; i < n; i++) {
	if (0 == fl[i])
	    res = i;
    }
    free(fl);
    fclose(fp);
    return res;
}

static int cdrom_tray(char *dev, int eject)
{
    int fd = -1;

    if (-1 == (fd = open(dev,O_RDONLY | O_NONBLOCK)))
	goto err;
    if (eject) {
	if (-1 == ioctl(fd,CDROMEJECT,NULL))
	    goto err;
    } else {
	if (-1 == ioctl(fd,CDROMCLOSETRAY,NULL))
	    goto err;
    }
    close(fd);
    return 0;

 err:
    if (-1 != fd)
	close(fd);
    return -1;
}

int
main(int argc, char *argv[])
{
    struct changer_params       params;
    struct changer_get_element  st;
    struct changer_get_element  *dt;
    struct changer_move         move;
    char                        **devs,line[80],mopt[80],*h;
    int    fd,i,slot,drive;
    int    try_umount = 0;
    int    eject_cdrom = 0;
    FILE   *fp;

    if (argc != 2) {
	fprintf(stderr,"Read the f*** manual!\n\n*plonk*\n\n");
	exit(1);
    }

    if (-1 == (fd = open(CHANGER,O_RDONLY))) {
	perror(PROG ": open " CHANGER);
	exit(1);
    }

    /* read changer status information */
    if (ioctl(fd,CHIOGPARAMS,&params)) {
	perror(PROG ": ioctl CHIOGPARAMS");
	exit(1);
    }
#if DEBUG
    fprintf(stderr,PROG ": %d drives, %d slots\n",
	    params.cp_ndrives,params.cp_nslots);
#endif

    dt = malloc(sizeof(struct changer_get_element)*params.cp_ndrives);
    for (i = 0; i < params.cp_ndrives; i++) {
        dt[i].cge_type=CHET_DT;
	dt[i].cge_unit=i;
	if (ioctl(fd,CHIOGELEM,dt+i)) {
	    fprintf(stderr,PROG ":ioctl CHIOGELEM mt %d: %s\n",
		    i,strerror(errno));
	    exit(1);
	}
	if (NULL != (h = strchr(dt[i].cge_pvoltag,' '))) *h = '\0';
	if (NULL != (h = strchr(dt[i].cge_avoltag,' '))) *h = '\0';
    }

    /* read config file */
    if (NULL == (fp = fopen(CONFIG, "r"))) {
	perror(PROG ": open " CONFIG);
	exit(1);
    }
    devs = malloc(sizeof(char*)*params.cp_ndrives);
    for (i = 0; NULL != fgets(line,79,fp);) {
	if (line[0] == '#' || line[0] == '\n')
	    continue;
	if (sscanf(line,"try_umount= %d",&try_umount))
	    continue;
	if (sscanf(line,"eject_cdrom= %d",&eject_cdrom))
	    continue;
        if (line==strstr(line,"mopt=")) {
	    strncpy(mopt,line+5,79);
	    mopt[strlen(mopt)-1]='\0';
	    continue;
	}

	devs[i] = malloc(32);
	if (!sscanf(line,"dev= %31s",devs[i])) {
	    fprintf(stderr,PROG ": config syntax error: %s",line);
	    exit(1);
	}
#if DEBUG
	fprintf(stderr,PROG ": drive %d: %s\n",i,devs[i]);
#endif
	i++;
    }
    fclose(fp);
    if (i != params.cp_ndrives) {
	fprintf(stderr,
		PROG ": number of drives (%d) does'nt match the\n"
		PROG ": number of dev=... lines (%d) in " CONFIG "\n",
		params.cp_ndrives,i);
	exit(1);
    }

    /* everything fine so far, lets check what key we got... */
    for (i = 0; argv[1][i];i++)
       if (!isdigit(argv[1][i]))
           break;
    if (!argv[1][i]) {
	/* we got a number */
	slot = atoi(argv[1]);
	if (slot < 0 || slot >= params.cp_nslots) {
	    fprintf(stderr,PROG ": slot %d is out of range\n",slot);
	    exit(1);
	}

	/* check drives */
	for (drive = -1, i = 0; i < params.cp_ndrives; i++) {
	    if ((dt[i].cge_status  &  CESTATUS_FULL) &&
		(dt[i].cge_flags   &  CGE_SRC)       &&
		(dt[i].cge_srctype == CHET_ST)       &&
		(dt[i].cge_srcunit == slot)) {
		drive = i;
		break;
	    }
	}

	if (-1 != drive) {
	    /* Ha!  requested media is still in a drive.  Nothing to do :-) */
	    printf("%s\t:%s\n",mopt,devs[drive]);
	    exit(0);
	}

	st.cge_type=CHET_ST;
	st.cge_unit=slot;
	if (ioctl(fd,CHIOGELEM,&st)) {
	    fprintf(stderr,PROG ": ioctl CHIOGELEM st %d: %s\n",
		    slot,strerror(errno));
	    exit(1);
	}

	if (!(st.cge_status & CESTATUS_FULL)) {
	    fprintf(stderr,PROG ": slot %d has no media\n",slot);
	    exit(1); 
	}
    } else {

	/* no number -- assume volume tag */

	/* check drives */
	for (drive = -1, i = 0; i < params.cp_ndrives; i++) {
	    if ((dt[i].cge_status & CESTATUS_FULL) &&
		(dt[i].cge_flags  & CGE_PVOLTAG)   &&
		(0 == strcmp(argv[1],dt[i].cge_pvoltag))) {
		drive = i;
		break;
	    }
	}

	if (-1 != drive) {
	    /* Ha!  requested media is still in a drive.  Nothing to do :-) */
	    printf("%s\t:%s\n",mopt,devs[drive]);
	    exit(0);
	}
	
	/* Find the tag */
	st.cge_type=CHET_ST;
	for (slot = -1, i = 0; i < params.cp_nslots; i++) {
            st.cge_unit=i;
            if (ioctl(fd,CHIOGELEM,&st)) {
		fprintf(stderr,PROG ": ioctl CHIOGELEM st %d: %s\n",
			i,strerror(errno));
		exit(1);
	    }

	    if (NULL != (h = strchr(st.cge_pvoltag,' '))) *h = '\0';
	    if (NULL != (h = strchr(st.cge_avoltag,' '))) *h = '\0';

	    if ((st.cge_status & CESTATUS_FULL) &&
		(st.cge_flags  & CGE_PVOLTAG)   &&
		(0 == strcmp(argv[1],st.cge_pvoltag))) {
		slot = i;
		break;
	    }
	}

	if (-1 == slot) {
	    fprintf(stderr,PROG ": volume tag %s not found\n",argv[1]);
	    exit(1);
	}
    }

    /* ok, requested media found, check where to put it now */

    /* look for a empty drive first... */
    for (i = 0, drive = -1; i < params.cp_ndrives; i++) {
	if (!(dt[i].cge_status & CESTATUS_FULL)) {
	    drive = i;
	    break;
	}
    }

    if (-1 == drive)
	/* failing that, look for a unmounted drive */
	drive = check_mtab(params.cp_ndrives,devs);

    if (-1 == drive && try_umount) {
	/* still no success -- tell automount to umount idle mount-points */
#if DEBUG
	fprintf(stderr,PROG ": sending SIGUSR1 to automount\n");
#endif
	kill(SIGUSR1,getppid());
	sleep(1); /* XXX */
	drive = check_mtab(params.cp_ndrives,devs);
    }

    if (-1 == drive) {
	/* bad luck */
	fprintf(stderr,PROG ": all drives busy, sorry\n");
	exit(1);
    }

    if (eject_cdrom) {
	if (0 != cdrom_tray(devs[drive],1))
	    exit(1);
    }
    
    if (dt[drive].cge_status & CESTATUS_FULL) {
	/* Hmm, full. Ok, put back the old media ... */
	if (!(dt[drive].cge_flags & CGE_SRC)) {
	    fprintf(stderr,PROG ": source element for drive %d unknown\n",
		    drive);
	    goto close_error_exit;
	}
	memset(&move,0,sizeof(struct changer_move));
	move.cm_totype   = dt[drive].cge_srctype;
	move.cm_tounit   = dt[drive].cge_srcunit;
	move.cm_fromtype = CHET_DT;
	move.cm_fromunit = drive;
	if (ioctl(fd,CHIOMOVE,&move)) {
	    fprintf(stderr,PROG ": ioctl MOVE (unload): %s\n",
		    strerror(errno));
	    goto close_error_exit;
	}
    }

    memset(&move,0,sizeof(struct changer_move));
    move.cm_totype   = CHET_DT;
    move.cm_tounit   = drive;
    move.cm_fromtype = CHET_ST;
    move.cm_fromunit = slot;
    if (ioctl(fd,CHIOMOVE,&move)) {
	fprintf(stderr,PROG ": ioctl MOVE (load): %s\n",
		strerror(errno));
	goto close_error_exit;
    }

    if (eject_cdrom)
	cdrom_tray(devs[drive],0);
    
    printf("%s\t:%s\n",mopt,devs[drive]);
    exit(0);

 close_error_exit:
    if (eject_cdrom)
	cdrom_tray(devs[drive],0);
    exit(1);
}