gen/FreeBSD/getmntinfo.c

   1 /*
   2  * Copyright (c) 1989, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #if defined(LIBC_SCCS) && !defined(lint)
  31 static char sccsid[] = "@(#)getmntinfo.c        8.1 (Berkeley) 6/4/93";
  32 #endif /* LIBC_SCCS and not lint */
  33 #include <sys/cdefs.h>
  34 __FBSDID("$FreeBSD: src/lib/libc/gen/getmntinfo.c,v 1.5 2007/01/09 00:27:54 imp Exp $");
  35
  36 #include <sys/param.h>
  37 #include <sys/ucred.h>
  38 #include <sys/mount.h>
  39 #include <errno.h>
  40 #include <stdlib.h>
  41
  42 struct getmntinfo_vars {
  43         struct statfs *mntbuf;
  44         int mntsize;
  45         long bufsize;
  46 };
  47
  48 /*
  49  * Return information about mounted filesystems.
  50  */
  51 static int
  52 getmntinfo_internal(struct getmntinfo_vars *vars, int flags)
  53 {
  54
  55         if (vars->mntsize <= 0 &&
  56             (vars->mntsize = getfsstat(0, 0, MNT_NOWAIT)) < 0) {
  57                 return (0);
  58         }
  59         if (vars->bufsize > 0 &&
  60             (vars->mntsize =
  61              getfsstat(vars->mntbuf, vars->bufsize, flags)) < 0) {
  62                 return (0);
  63         }
  64         while (vars->bufsize <= vars->mntsize * sizeof(struct statfs)) {
  65                 if (vars->mntbuf) {
  66                         free(vars->mntbuf);
  67                 }
  68                 vars->bufsize = (vars->mntsize + 1) * sizeof(struct statfs);
  69                 if ((vars->mntbuf =
  70                      (struct statfs *)malloc(vars->bufsize)) == 0) {
  71                         return (0);
  72                 }
  73                 if ((vars->mntsize =
  74                      getfsstat(vars->mntbuf, vars->bufsize, flags)) < 0) {
  75                         return (0);
  76                 }
  77         }
  78         return (vars->mntsize);
  79 }
  80
  81 /* Legacy version that keeps the buffer around. */
  82 int
  83 getmntinfo(struct statfs **mntbufp, int flags)
  84 {
  85         static struct getmntinfo_vars vars;
  86         int rv;
  87
  88         rv = getmntinfo_internal(&vars, flags);
  89         /* Unconditional assignment matches legacy behavior. */
  90         *mntbufp = vars.mntbuf;
  91         return (rv);
  92 }
  93
  94 /* Thread-safe version where the caller owns the newly-allocated buffer. */
  95 int
  96 getmntinfo_r_np(struct statfs **mntbufp, int flags)
  97 {
  98         struct getmntinfo_vars vars = { 0 };
  99         int rv, save_errno;
 100
 101         if ((rv = getmntinfo_internal(&vars, flags)) != 0) {
 102                 *mntbufp = vars.mntbuf;
 103         } else {
 104                 save_errno = errno;
 105                 free(vars.mntbuf);
 106                 errno = save_errno;
 107         }
 108         return (rv);
 109 }