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Viewing changes to shlibs/blkid/src/topology/dm.c

  • Committer: Package Import Robot
  • Author(s): LaMont Jones
  • Date: 2011-11-03 15:38:23 UTC
  • mto: (4.5.5 sid) (1.6.4)
  • mto: This revision was merged to the branch mainline in revision 85.
  • Revision ID: package-import@ubuntu.com-20111103153823-10sx16jprzxlhkqf
Import upstream version 2.20.1

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shlibs/blkid/src/topology/dm.c
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/*
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 * device-mapper (dm) topology
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 * -- this is fallback for old systems where the topology information is not
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 *    exported by sysfs
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 *
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 * Copyright (C) 2009 Karel Zak <kzak@redhat.com>
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 *
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 * This file may be redistributed under the terms of the
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 * GNU Lesser General Public License.
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 *
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 */
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#include <errno.h>
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#include <fcntl.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include "topology.h"
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static int is_dm_device(dev_t devno)
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{
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        return blkid_driver_has_major("device-mapper", major(devno));
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}
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static int probe_dm_tp(blkid_probe pr, const struct blkid_idmag *mag)
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{
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        const char *paths[] = {
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                "/usr/local/sbin/dmsetup",
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                "/usr/sbin/dmsetup",
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                "/sbin/dmsetup"
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        };
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        int i, dmpipe[] = { -1, -1 }, stripes, stripesize;
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        char *cmd = NULL;
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        FILE *stream = NULL;
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        long long  offset, size;
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        dev_t devno = blkid_probe_get_devno(pr);
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        if (!devno)
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                goto nothing;           /* probably not a block device */
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        if (!is_dm_device(devno))
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                goto nothing;
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        for (i = 0; i < ARRAY_SIZE(paths); i++) {
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                struct stat sb;
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                if (stat(paths[i], &sb) == 0) {
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                        cmd = (char *) paths[i];
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                        break;
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                }
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        }
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        if (!cmd)
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                goto nothing;
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        if (pipe(dmpipe) < 0) {
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                DBG(DEBUG_LOWPROBE,
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                        printf("Failed to open pipe: errno=%d", errno));
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                goto nothing;
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        }
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        switch (fork()) {
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        case 0:
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        {
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                char *dmargv[7], maj[16], min[16];
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                /* Plumbing */
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                close(dmpipe[0]);
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                if (dmpipe[1] != STDOUT_FILENO)
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                        dup2(dmpipe[1], STDOUT_FILENO);
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                /* The libblkid library could linked with setuid programs */
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                if (setgid(getgid()) < 0)
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                         exit(1);
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                if (setuid(getuid()) < 0)
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                         exit(1);
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                snprintf(maj, sizeof(maj), "%d", major(devno));
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                snprintf(min, sizeof(min), "%d", minor(devno));
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                dmargv[0] = cmd;
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                dmargv[1] = "table";
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                dmargv[2] = "-j";
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                dmargv[3] = maj;
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                dmargv[4] = "-m";
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                dmargv[5] = min;
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                dmargv[6] = NULL;
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                execv(dmargv[0], dmargv);
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                DBG(DEBUG_LOWPROBE,
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                        printf("Failed to execute %s: errno=%d", cmd, errno));
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                exit(1);
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        }
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        case -1:
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                DBG(DEBUG_LOWPROBE,
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                        printf("Failed to forking: errno=%d", errno));
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                goto nothing;
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        default:
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                break;
103
 
        }
104
 
 
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        stream = fdopen(dmpipe[0], "r");
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        if (!stream)
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                goto nothing;
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109
 
        i = fscanf(stream, "%lld %lld striped %d %d ",
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                        &offset, &size, &stripes, &stripesize);
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        if (i != 4)
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                goto nothing;
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114
 
        blkid_topology_set_minimum_io_size(pr, stripesize << 9);
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        blkid_topology_set_optimal_io_size(pr, (stripes * stripesize) << 9);
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117
 
        fclose(stream);
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        close(dmpipe[1]);
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        return 0;
120
 
 
121
 
nothing:
122
 
        if (stream)
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                fclose(stream);
124
 
        else if (dmpipe[0] != -1)
125
 
                close(dmpipe[0]);
126
 
        if (dmpipe[1] != -1)
127
 
                close(dmpipe[1]);
128
 
        return 1;
129
 
}
130
 
 
131
 
const struct blkid_idinfo dm_tp_idinfo =
132
 
{
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        .name           = "dm",
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        .probefunc      = probe_dm_tp,
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        .magics         = BLKID_NONE_MAGIC
136
 
};
137