IABSD.fr/src/lib/libutil/readlabel.c

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• Author : deraadt
  Date : 2019-06-28 13:32:41
  Hash : df69c215
  Message : When system calls indicate an error they return -1, not some arbitrary value < 0. errno is only updated in this case. Change all (most?) callers of syscalls to follow this better, and let's see if this strictness helps us in the future.

• lib/libutil/readlabel.c

• /*	$OpenBSD: readlabel.c,v 1.15 2019/06/28 13:32:43 deraadt Exp $	*/
  
  /*
   * Copyright (c) 1996, Jason Downs.  All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS
   * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
   * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT,
   * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   */
  
  #include <sys/types.h>
  #include <sys/disk.h>
  #include <sys/dkio.h>
  #define DKTYPENAMES
  #include <sys/disklabel.h>
  #include <sys/ioctl.h>
  #include <sys/stat.h>
  #include <stdio.h>
  #include <err.h>
  #include <errno.h>
  #include <limits.h>
  #include <fcntl.h>
  #include <paths.h>
  #include <string.h>
  #include <unistd.h>
  
  #include "util.h"
  
  /*
   * Try to get a disklabel for the specified device, and return mount_xxx
   * style filesystem type name for the specified partition.
   */
  char *
  readlabelfs(char *device, int verbose)
  {
  	char rpath[PATH_MAX];
  	struct dk_diskmap dm;
  	struct disklabel dk;
  	char part, *type;
  	struct stat sbuf;
  	int fd = -1;
  
  	/* Perform disk mapping if device is given as a DUID. */
  	if (isduid(device, 0)) {
  		if ((fd = open("/dev/diskmap", O_RDONLY|O_CLOEXEC)) != -1) {
  			bzero(&dm, sizeof(struct dk_diskmap));
  			strlcpy(rpath, device, sizeof(rpath));
  			part = rpath[strlen(rpath) - 1];
  			dm.device = rpath;
  			dm.fd = fd;
  			dm.flags = DM_OPENPART;
  			if (ioctl(fd, DIOCMAP, &dm) == -1)
  				close(fd);
  			else
  				goto disklabel;
  		}
  	}
  
  	/* Assuming device is of the form /dev/??p, build a raw partition. */
  	if (stat(device, &sbuf) == -1) {
  		if (verbose)
  			warn("%s", device);
  		return (NULL);
  	}
  	switch (sbuf.st_mode & S_IFMT) {
  	case S_IFCHR:
  		/* Ok... already a raw device.  Hmm. */
  		strlcpy(rpath, device, sizeof(rpath));
  
  		/* Change partition name. */
  		part = rpath[strlen(rpath) - 1];
  		rpath[strlen(rpath) - 1] = 'a' + getrawpartition();
  		break;
  	case S_IFBLK:
  		if (strlen(device) > sizeof(_PATH_DEV) - 1) {
  			snprintf(rpath, sizeof(rpath), "%sr%s", _PATH_DEV,
  			    &device[sizeof(_PATH_DEV) - 1]);
  			/* Change partition name. */
  			part = rpath[strlen(rpath) - 1];
  			rpath[strlen(rpath) - 1] = 'a' + getrawpartition();
  			break;
  		}
  		/* FALLTHROUGH */
  	default:
  		if (verbose)
  			warnx("%s: not a device node", device);
  		return (NULL);
  	}
  
  	/* If rpath doesn't exist, change that partition back. */
  	fd = open(rpath, O_RDONLY|O_CLOEXEC);
  	if (fd == -1) {
  		if (errno == ENOENT) {
  			rpath[strlen(rpath) - 1] = part;
  
  			fd = open(rpath, O_RDONLY|O_CLOEXEC);
  			if (fd == -1) {
  				if (verbose)
  					warn("%s", rpath);
  				return (NULL);
  			}
  		} else {
  			if (verbose)
  				warn("%s", rpath);
  			return (NULL);
  		}
  	}
  
  disklabel:
  
  	if (ioctl(fd, DIOCGDINFO, &dk) == -1) {
  		if (verbose)
  			warn("%s: couldn't read disklabel", rpath);
  		close(fd);
  		return (NULL);
  	}
  	close(fd);
  
  	if (dk.d_partitions[part - 'a'].p_fstype >= FSMAXTYPES) {
  		if (verbose)
  			warnx("%s: bad filesystem type in label", rpath);
  		return (NULL);
  	}
  
  	type = fstypesnames[dk.d_partitions[part - 'a'].p_fstype];
  	return ((type[0] == '\0') ? NULL : type);
  }