iscsi-probe.c

这个linux源代码是很全面的~基本完整了~使用c编译的~由于时间问题我没有亲自测试~但就算用来做参考资料也是非常好的

        set_current_state(TASK_UNINTERRUPTIBLE);
        schedule_timeout(MSECS_TO_JIFFIES(20));
        return 1;
    } 

    return rc;
}

/* caller must hold the iscsi_lun_probe_mutex */
static int iscsi_probe_lun(iscsi_session_t *session, int lun)
{
    char str[80];
    int rc;

    if (lun >= ISCSI_MAX_LUN)
        return 0;

    sprintf(str, "scsi add-single-device %d %d %d %d\n", 
            session->host_no, session->channel, session->target_id, lun);
    str[sizeof(str) - 1] = '\0';

    rc = write_proc_scsi_scsi(session, str);
    if (rc < 0) {
        /* clear the newline */
        str[strlen(str) - 1] = '\0';
        printk("iSCSI: session %p error %d writing '%s' to /proc/scsi/scsi\n",
               session, rc, str);
        return 0;
    }
    
    return rc;
}

static int iscsi_remove_lun(iscsi_session_t *session, int lun)
{
    char str[88];
    int rc = 0;

    sprintf(str, "scsi remove-single-device %d %d %d %d\n", 
            session->host_no, session->channel, session->target_id, lun);
    str[sizeof(str) - 1] = '\0';
    
    rc = write_proc_scsi_scsi(session, str);
    if (rc < 0) {
        /* clear the newline */
        str[strlen(str) - 1] = '\0';
        printk("iSCSI: session %p error %d writing '%s' to /proc/scsi/scsi\n",
               session, rc, str);
        return 0;
    }
    else {
        /* removed it */
        clear_bit(lun, session->luns_activated);
        return 1;
    }
    
    return rc;
}


static void empty_directory(char *dir, char *data, int size)
{
    int fd;
    struct dirent dent;
    int rc, processed;
    char *name = dir + strlen(dir);
    
    /* there should only be directories in the target dir */
    if ((fd = open(dir, O_DIRECTORY|O_RDONLY, 0)) >= 0) {
        /* loop doing getdents, and unlinking files */
        do {
            rc = getdents(fd, (struct dirent *)data, size);
            DEBUG_FLOW3("iSCSI: getdents %s, size %d, returned %d\n", 
                        dir, size, rc);
            processed = 0;
            while (processed < rc) {
                memcpy(&dent, &data[processed], sizeof(dent));
                strcpy(name, &data[processed] + offsetof(struct dirent, d_name));
                if (strcmp(name, ".") && strcmp(name, "..")) {
                    DEBUG_FLOW1("iSCSI: unlink %s\n", dir);
                    unlink(dir);
                }
                processed += dent.d_reclen; 
            }
        } while (rc > 0);
        
        name[0] = '\0';
        close(fd);
    }
}

void iscsi_remove_luns(iscsi_session_t *session)
{
    int l;
    mm_segment_t oldfs;
    char *data = session->RxBuf;
    int size = sizeof(session->RxBuf) - 1;
    char *lun_dir = session->target_link_dir + strlen(session->target_link_dir);
    char *bus_dir = lun_dir - 2; /* before the slash */
    char c;

    /* try to release the kernel's SCSI device structures for every LUN */
    down(&iscsi_lun_probe_mutex);

    oldfs = get_fs();
    set_fs( get_ds() );
    
    for (l = 0; l < ISCSI_MAX_LUN; l++) {
        if (session->target_link_dir[0] == '/') {
            sprintf(lun_dir, "lun%d/", l);
            
            /* this assumes the session isn't using the RxBuf right now */
            empty_directory(session->target_link_dir, data, size);
            
            rmdir(session->target_link_dir);
        }
        if (test_bit(l, session->luns_activated)) {
            /* tell Linux to release the Scsi_Devices */
            iscsi_remove_lun(session, l);
        }
    }

    if (session->target_link_dir[0] == '/') {
        /* and get rid of the target dir itself */
        *lun_dir = '\0';
        DEBUG_FLOW1("iSCSI: rmdir %s\n", session->target_link_dir);
        rmdir(session->target_link_dir);

        /* if the bus dir is empty now, get rid of it too, but don't corrupt the session's target dir */
        while (*bus_dir != '/')
            bus_dir--;
        bus_dir++; /* leave the slash */
        c = *bus_dir;
        *bus_dir = '\0';
        
        DEBUG_FLOW1("iSCSI: rmdir %s\n", session->target_link_dir);
        rmdir(session->target_link_dir);
        *bus_dir = c;
    }

    set_fs( oldfs );

    up(&iscsi_lun_probe_mutex);
}

/* find all dir prefixes of pathname, and make them all if they don't exist */
static void ensure_directories_exist(char *pathname, mode_t dir_mode)
{
    char *end = pathname;

    /* skip leading slashes */
    while (end && *end && (*end == '/'))
        end++;

    while (end && (*end != '\0')) {
        /* if there is another slash, make the dir.
         * FIXME: we ought to ignore errors when the directory exists,
         * but report errors where the directory doesn't exist and
         * we failed to create it.
         */
        while ((*end != '/') && (*end != '\0'))
            end++;
        
        if (*end == '/') {
            *end = '\0';
            mkdir(pathname, dir_mode);
            *end = '/';
            end++;
        }
    }
}

static int get_device_scsi_quad(char *device_name, int *host, int *channel, int *target, int *lun)
{
    int ret = 0;
    u_long info[2];
    struct file *filp = NULL;
    struct inode *inode = NULL;

    filp = filp_open(device_name, O_RDONLY|O_NONBLOCK, 0);
    if (IS_ERR(filp)) {
        return 0;
    }
    
    memset(info, 0, sizeof(info));
    inode = filp->f_dentry->d_inode;
    if (filp->f_op->ioctl(inode, filp, SCSI_IOCTL_GET_IDLUN, (unsigned long)info) == 0) {
        if (target)
            *target = info[0] & 0xff;
        if (lun)
            *lun = (info[0] >> 8) & 0xff;
        if (channel)
            *channel = (info[0] >> 16) & 0xff;
#if ( LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,0) )
        /* 2.4 kernels give us all the info we need with that ioctl. */
        if (host)
            *host = ((info[0] >> 24) & 0xff);                               

        ret = 1;
#else
        /* 2.2 kernels have another ioctl to get the host number, and set the host
         * above to something useless to us.
         */
        memset(info, 0, sizeof(info));
        if (filp->f_op->ioctl(inode, filp, SCSI_IOCTL_GET_BUS_NUMBER, (unsigned long)info) == 0) {
            if (host)
                *host = info[0];
            ret = 1;
        }
#endif
    }

    filp_close(filp, 0);
    return ret;
}


static void iscsi_update_disk_links(iscsi_session_t *session, int max_sd_devices, int max_sd_partitions, mode_t dir_mode)
{
    int i;
    char devname[20];
    /* we've reserved enough space in session->target_link_dir so that we can use it to build pathnames */
    char *lun_dir = session->target_link_dir + strlen(session->target_link_dir);

    /* FIXME: can we get the number of devices supported from the running kernel? */
    for (i=0; i < max_sd_devices; i++) {
        int host = -1, channel = -1, id = -1, lun = -1;

        if (i < 26) {
            sprintf(devname, "/dev/sd%c", 'a' + i);
        }
        else {
            /* double char names for disknum 26+ */
            sprintf(devname, "/dev/sd%c%c", 'a' + (i / 26) - 1, 'a' + (i % 26));
        }

        if (get_device_scsi_quad(devname, &host, &channel, &id, &lun)) {
            if ((host == session->host_no) && (channel == session->channel) && (id == session->target_id)) {
                char *partition = devname + strlen(devname);
                char *link;
                int p;

                DEBUG_INIT4("iSCSI: disk device node %s = bus %d target %d LUN %d\n", devname, session->iscsi_bus, id, lun);
                
                /* ensure the LUN dir exists */
                sprintf(lun_dir, "lun%d/", lun);
                ensure_directories_exist(session->target_link_dir, dir_mode);

                link = lun_dir + strlen(lun_dir);

                /* symlink the whole-disk device */
                strcpy(link, "disk");
                unlink(session->target_link_dir); /* remove any existing symlink */
                symlink(devname, session->target_link_dir); /* make a new symlink */
                
                /* and make links for each possible disk partition as well,
                 * since we don't want to have to track what partitions get added or removed.
                 * This works just like the normal partition device nodes, which
                 * are always present, but may or may not be openable.
                 */
                for (p = 1; p <= max_sd_partitions; p++) {
                    sprintf(partition, "%d", p);
                    sprintf(link, "part%d", p);
                    unlink(session->target_link_dir);
                    symlink(devname, session->target_link_dir);
                }

            }
        }
    }

    /* restore the session's target dir */
    *lun_dir = '\0';
}

static void iscsi_update_tape_links(iscsi_session_t *session, int max_st_devices, mode_t dir_mode)
{
    int i;
    char devname[20];
    /* we've reserved enough space in session->target_link_dir so that we can use it to build pathnames */
    char *lun_dir = session->target_link_dir + strlen(session->target_link_dir);

    /* FIXME: can we get the number of devices supported from the running kernel? */
    for (i=0; i < max_st_devices; i++) {
        int host = -1, channel = -1, id = -1, lun = -1;

        /* we check the no-rewind device to avoid having side-effects */
        sprintf(devname, "/dev/nst%d", i);

        if (get_device_scsi_quad(devname, &host, &channel, &id, &lun)) {
            if ((host == session->host_no) && (channel == session->channel) && (id == session->target_id)) {
                char *link;

                DEBUG_INIT4("iSCSI: tape device node %s = bus %d target %d LUN %d\n", devname, session->iscsi_bus, id, lun);
                
                /* ensure the LUN dir exists */
                sprintf(lun_dir, "lun%d/", lun);
                ensure_directories_exist(session->target_link_dir, dir_mode);

                link = lun_dir + strlen(lun_dir);

                /* auto-rewind nodes */
                strcpy(link, "mt");
                unlink(session->target_link_dir); /* remove any existing symlink */
                sprintf(devname, "/dev/st%d", i);
                symlink(devname, session->target_link_dir); /* make a new symlink */

                strcpy(link, "mtl");
                unlink(session->target_link_dir); /* remove any existing symlink */
                sprintf(devname, "/dev/st%dl", i);
                symlink(devname, session->target_link_dir); /* make a new symlink */

                strcpy(link, "mtm");
                unlink(session->target_link_dir); /* remove any existing symlink */
                sprintf(devname, "/dev/st%dm", i);
                symlink(devname, session->target_link_dir); /* make a new symlink */

                strcpy(link, "mta");
                unlink(session->target_link_dir); /* remove any existing symlink */
                sprintf(devname, "/dev/st%da", i);
                symlink(devname, session->target_link_dir); /* make a new symlink */
                    
                /* no rewind nodes */
                strcpy(link, "mtn");
                unlink(session->target_link_dir); /* remove any existing symlink */
                sprintf(devname, "/dev/nst%d", i);
                symlink(devname, session->target_link_dir); /* make a new symlink */

                strcpy(link, "mtln");
                unlink(session->target_link_dir); /* remove any existing symlink */
                sprintf(devname, "/dev/nst%dl", i);
                symlink(devname, session->target_link_dir); /* make a new symlink */

                strcpy(link, "mtmn");
                unlink(session->target_link_dir); /* remove any existing symlink */
                sprintf(devname, "/dev/nst%dm", i);
                symlink(devname, session->target_link_dir); /* make a new symlink */

                strcpy(link, "mtan");
                unlink(session->target_link_dir); /* remove any existing symlink */
                sprintf(devname, "/dev/nst%da", i);
                symlink(devname, session->target_link_dir); /* make a new symlink */
            }
        }
    }

    /* restore the session's target dir */
    *lun_dir = '\0';
}

static void iscsi_update_generic_links(iscsi_session_t *session, int max_sg_devices, mode_t dir_mode)
{
    int i;
    char devname[20];
    /* we've reserved enough space in session->target_link_dir so that we can use it to build pathnames */
    char *lun_dir = session->target_link_dir + strlen(session->target_link_dir);
    char *link;

    /* FIXME: can we get the number of devices supported from the running kernel? */
    for (i=0; i < max_sg_devices; i++) {