source: MondoRescue/branches/stable/mindi-busybox/e2fsprogs/blkid/devname.c @ 821

/*
 * devname.c - get a dev by its device inode name
 *
 * Copyright (C) Andries Brouwer
 * Copyright (C) 1999, 2000, 2001, 2002, 2003 Theodore Ts'o
 * Copyright (C) 2001 Andreas Dilger
 *
 * %Begin-Header%
 * This file may be redistributed under the terms of the
 * GNU Lesser General Public License.
 * %End-Header%
 */

#include <stdio.h>
#include <string.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#if HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#if HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#if HAVE_ERRNO_H
#include <errno.h>
#endif
#if HAVE_SYS_MKDEV_H
#include <sys/mkdev.h>
#endif
#include <time.h>

#include "blkidP.h"

/*
 * Find a dev struct in the cache by device name, if available.
 *
 * If there is no entry with the specified device name, and the create
 * flag is set, then create an empty device entry.
 */
blkid_dev blkid_get_dev(blkid_cache cache, const char *devname, int flags)
{
    blkid_dev dev = NULL, tmp;
    struct list_head *p;

    if (!cache || !devname)
        return NULL;

    list_for_each(p, &cache->bic_devs) {
        tmp = list_entry(p, struct blkid_struct_dev, bid_devs);
        if (strcmp(tmp->bid_name, devname))
            continue;

        DBG(DEBUG_DEVNAME,
            printf("found devname %s in cache\n", tmp->bid_name));
        dev = tmp;
        break;
    }

    if (!dev && (flags & BLKID_DEV_CREATE)) {
        dev = blkid_new_dev();
        if (!dev)
            return NULL;
        dev->bid_name = blkid_strdup(devname);
        dev->bid_cache = cache;
        list_add_tail(&dev->bid_devs, &cache->bic_devs);
        cache->bic_flags |= BLKID_BIC_FL_CHANGED;
    }

    if (flags & BLKID_DEV_VERIFY)
        dev = blkid_verify(cache, dev);
    return dev;
}

/*
 * Probe a single block device to add to the device cache.
 */
static void probe_one(blkid_cache cache, const char *ptname,
              dev_t devno, int pri)
{
    blkid_dev dev = NULL;
    struct list_head *p;
    const char **dir;
    char *devname = NULL;

    /* See if we already have this device number in the cache. */
    list_for_each(p, &cache->bic_devs) {
        blkid_dev tmp = list_entry(p, struct blkid_struct_dev,
                       bid_devs);
        if (tmp->bid_devno == devno) {
            dev = blkid_verify(cache, tmp);
            break;
        }
    }
    if (dev && dev->bid_devno == devno)
        goto set_pri;

    /*
     * Take a quick look at /dev/ptname for the device number.  We check
     * all of the likely device directories.  If we don't find it, or if
     * the stat information doesn't check out, use blkid_devno_to_devname()
     * to find it via an exhaustive search for the device major/minor.
     */
    for (dir = blkid_devdirs; *dir; dir++) {
        struct stat st;
        char device[256];

        sprintf(device, "%s/%s", *dir, ptname);
        if ((dev = blkid_get_dev(cache, device, BLKID_DEV_FIND)) &&
            dev->bid_devno == devno)
            goto set_pri;

        if (stat(device, &st) == 0 && S_ISBLK(st.st_mode) &&
            st.st_rdev == devno) {
            devname = blkid_strdup(device);
            break;
        }
    }
    if (!devname) {
        devname = blkid_devno_to_devname(devno);
        if (!devname)
            return;
    }
    dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL);
    free(devname);

set_pri:
    if (!pri && !strncmp(ptname, "md", 2))
        pri = BLKID_PRI_MD;
    if (dev)
        dev->bid_pri = pri;
    return;
}

#define PROC_PARTITIONS "/proc/partitions"
#define VG_DIR      "/proc/lvm/VGs"

/*
 * This function initializes the UUID cache with devices from the LVM
 * proc hierarchy.  We currently depend on the names of the LVM
 * hierarchy giving us the device structure in /dev.  (XXX is this a
 * safe thing to do?)
 */
#ifdef VG_DIR
#include <dirent.h>
static dev_t lvm_get_devno(const char *lvm_device)
{
    FILE *lvf;
    char buf[1024];
    int ma, mi;
    dev_t ret = 0;

    DBG(DEBUG_DEVNAME, printf("opening %s\n", lvm_device));
    if ((lvf = fopen(lvm_device, "r")) == NULL) {
        DBG(DEBUG_DEVNAME, printf("%s: (%d) %s\n", lvm_device, errno,
                      strerror(errno)));
        return 0;
    }

    while (fgets(buf, sizeof(buf), lvf)) {
        if (sscanf(buf, "device: %d:%d", &ma, &mi) == 2) {
            ret = makedev(ma, mi);
            break;
        }
    }
    fclose(lvf);

    return ret;
}

static void lvm_probe_all(blkid_cache cache)
{
    DIR     *vg_list;
    struct dirent   *vg_iter;
    int     vg_len = strlen(VG_DIR);
    dev_t       dev;

    if ((vg_list = opendir(VG_DIR)) == NULL)
        return;

    DBG(DEBUG_DEVNAME, printf("probing LVM devices under %s\n", VG_DIR));

    while ((vg_iter = readdir(vg_list)) != NULL) {
        DIR     *lv_list;
        char        *vdirname;
        char        *vg_name;
        struct dirent   *lv_iter;

        vg_name = vg_iter->d_name;
        if (!strcmp(vg_name, ".") || !strcmp(vg_name, ".."))
            continue;
        vdirname = xmalloc(vg_len + strlen(vg_name) + 8);
        sprintf(vdirname, "%s/%s/LVs", VG_DIR, vg_name);

        lv_list = opendir(vdirname);
        free(vdirname);
        if (lv_list == NULL)
            continue;

        while ((lv_iter = readdir(lv_list)) != NULL) {
            char        *lv_name, *lvm_device;

            lv_name = lv_iter->d_name;
            if (!strcmp(lv_name, ".") || !strcmp(lv_name, ".."))
                continue;

            lvm_device = xmalloc(vg_len + strlen(vg_name) +
                        strlen(lv_name) + 8);
            sprintf(lvm_device, "%s/%s/LVs/%s", VG_DIR, vg_name,
                lv_name);
            dev = lvm_get_devno(lvm_device);
            sprintf(lvm_device, "%s/%s", vg_name, lv_name);
            DBG(DEBUG_DEVNAME, printf("LVM dev %s: devno 0x%04X\n",
                          lvm_device,
                          (unsigned int) dev));
            probe_one(cache, lvm_device, dev, BLKID_PRI_LVM);
            free(lvm_device);
        }
        closedir(lv_list);
    }
    closedir(vg_list);
}
#endif

#define PROC_EVMS_VOLUMES "/proc/evms/volumes"

static int
evms_probe_all(blkid_cache cache)
{
    char line[100];
    int ma, mi, sz, num = 0;
    FILE *procpt;
    char device[110];

    procpt = fopen(PROC_EVMS_VOLUMES, "r");
    if (!procpt)
        return 0;
    while (fgets(line, sizeof(line), procpt)) {
        if (sscanf (line, " %d %d %d %*s %*s %[^\n ]",
                &ma, &mi, &sz, device) != 4)
            continue;

        DBG(DEBUG_DEVNAME, printf("Checking partition %s (%d, %d)\n",
                      device, ma, mi));

        probe_one(cache, device, makedev(ma, mi), BLKID_PRI_EVMS);
        num++;
    }
    fclose(procpt);
    return num;
}

/*
 * Read the device data for all available block devices in the system.
 */
int blkid_probe_all(blkid_cache cache)
{
    FILE *proc;
    char line[1024];
    char ptname0[128], ptname1[128], *ptname = 0;
    char *ptnames[2];
    dev_t devs[2];
    int ma, mi;
    unsigned long long sz;
    int lens[2] = { 0, 0 };
    int which = 0, last = 0;

    ptnames[0] = ptname0;
    ptnames[1] = ptname1;

    if (!cache)
        return -BLKID_ERR_PARAM;

    if (cache->bic_flags & BLKID_BIC_FL_PROBED &&
        time(0) - cache->bic_time < BLKID_PROBE_INTERVAL)
        return 0;

    blkid_read_cache(cache);
    evms_probe_all(cache);
#ifdef VG_DIR
    lvm_probe_all(cache);
#endif

    proc = fopen(PROC_PARTITIONS, "r");
    if (!proc)
        return -BLKID_ERR_PROC;

    while (fgets(line, sizeof(line), proc)) {
        last = which;
        which ^= 1;
        ptname = ptnames[which];

        if (sscanf(line, " %d %d %llu %128[^\n ]",
               &ma, &mi, &sz, ptname) != 4)
            continue;
        devs[which] = makedev(ma, mi);

        DBG(DEBUG_DEVNAME, printf("read partition name %s\n", ptname));

        /* Skip whole disk devs unless they have no partitions
         * If we don't have a partition on this dev, also
         * check previous dev to see if it didn't have a partn.
         * heuristic: partition name ends in a digit.
         *
         * Skip extended partitions.
         * heuristic: size is 1
         *
         * FIXME: skip /dev/{ida,cciss,rd} whole-disk devs
         */

        lens[which] = strlen(ptname);
        if (isdigit(ptname[lens[which] - 1])) {
            DBG(DEBUG_DEVNAME,
                printf("partition dev %s, devno 0x%04X\n",
                   ptname, (unsigned int) devs[which]));

            if (sz > 1)
                probe_one(cache, ptname, devs[which], 0);
            lens[which] = 0;
            lens[last] = 0;
        } else if (lens[last] && strncmp(ptnames[last], ptname,
                         lens[last])) {
            DBG(DEBUG_DEVNAME,
                printf("whole dev %s, devno 0x%04X\n",
                   ptnames[last], (unsigned int) devs[last]));
            probe_one(cache, ptnames[last], devs[last], 0);
            lens[last] = 0;
        }
    }

    /* Handle the last device if it wasn't partitioned */
    if (lens[which])
        probe_one(cache, ptname, devs[which], 0);

    fclose(proc);

    cache->bic_time = time(0);
    cache->bic_flags |= BLKID_BIC_FL_PROBED;
    blkid_flush_cache(cache);
    return 0;
}

#ifdef TEST_PROGRAM
int main(int argc, char **argv)
{
    blkid_cache cache = NULL;
    int ret;

    blkid_debug_mask = DEBUG_ALL;
    if (argc != 1) {
        fprintf(stderr, "Usage: %s\n"
            "Probe all devices and exit\n", argv[0]);
        exit(1);
    }
    if ((ret = blkid_get_cache(&cache, bb_dev_null)) != 0) {
        fprintf(stderr, "%s: error creating cache (%d)\n",
            argv[0], ret);
        exit(1);
    }
    if (blkid_probe_all(cache) < 0)
        printf("%s: error probing devices\n", argv[0]);

    blkid_put_cache(cache);
    return (0);
}
#endif