• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 368
  • Last Modified:

c++/Linux checking available hard drive space

I have a client and server which transfers files back and
fourth, each runs on its own machine. I wanted to check the available hard drive space to make sure I have room
to save a file as it's received before I save it.
With the first packet of the file I have the size of the file to save, I just need to find out how to query the
hard drive and compare.
0
mitchguy
Asked:
mitchguy
  • 3
1 Solution
 
jkrCommented:
'df' from the GNU file utils does that - you can get the source code here: ftp://ftp.gnu.org/pub/gnu/fileutils/fileutils-4.1.tar.gz
0
 
jkrCommented:
BTW, 'df' does that by calling 'statfs()':

STATFS(2)           Linux Programmer's Manual           STATFS(2)


NAME
       statfs, fstatfs - get file system statistics

SYNOPSIS
       #include <sys/vfs.h>

       int statfs(const char *path, struct statfs *buf);
       int fstatfs(int fd, struct statfs *buf);

DESCRIPTION
       statfs  returns  information  about a mounted file system.
       path is the path name  of  any  file  within  the  mounted
       filesystem.   buf  is  a  pointer  to  a  statfs structure
       defined as follows:

              struct statfs {
                 long    f_type;     /* type of filesystem (see below) */
                 long    f_bsize;    /* optimal transfer block size */
                 long    f_blocks;   /* total data blocks in file system */
                 long    f_bfree;    /* free blocks in fs */
                 long    f_bavail;   /* free blocks avail to non-superuser */
                 long    f_files;    /* total file nodes in file system */
                 long    f_ffree;    /* free file nodes in fs */
                 fsid_t  f_fsid;     /* file system id */
                 long    f_namelen;  /* maximum length of filenames */
                 long    f_spare[6]; /* spare for later */
              };

              File system types:

              linux/affs_fs.h:
                 AFFS_SUPER_MAGIC      0xADFF
              linux/ext_fs.h:
                 EXT_SUPER_MAGIC       0x137D
              linux/ext2_fs.h:
                 EXT2_OLD_SUPER_MAGIC  0xEF51
                 EXT2_SUPER_MAGIC      0xEF53
              linux/hpfs_fs.h:
                 HPFS_SUPER_MAGIC      0xF995E849
              linux/iso_fs.h:
                 ISOFS_SUPER_MAGIC     0x9660
              linux/minix_fs.h:
                 MINIX_SUPER_MAGIC     0x137F /* orig. minix */
                 MINIX_SUPER_MAGIC2    0x138F /* 30 char minix */
                 MINIX2_SUPER_MAGIC    0x2468 /* minix V2 */
                 MINIX2_SUPER_MAGIC2   0x2478 /* minix V2, 30 char names */
              linux/msdos_fs.h:
                 MSDOS_SUPER_MAGIC     0x4d44
              linux/ncp_fs.h:
                 NCP_SUPER_MAGIC       0x564c
              linux/nfs_fs.h:
                 NFS_SUPER_MAGIC       0x6969
              linux/proc_fs.h:
                 PROC_SUPER_MAGIC      0x9fa0
              linux/smb_fs.h:
                 SMB_SUPER_MAGIC       0x517B
              linux/sysv_fs.h:
                 XENIX_SUPER_MAGIC     0x012FF7B4
                 SYSV4_SUPER_MAGIC     0x012FF7B5
                 SYSV2_SUPER_MAGIC     0x012FF7B6
                 COH_SUPER_MAGIC       0x012FF7B7
              linux/ufs_fs.h:
                 UFS_MAGIC             0x00011954
              linux/xia_fs.h:
                 _XIAFS_SUPER_MAGIC    0x012FD16D

       Fields that are undefined for a particular file system are
       set  to -1.  fstatfs returns the same information about an
       open file referenced by descriptor fd.

RETURN VALUE
       On success, zero is returned.  On error, -1  is  returned,
       and errno is set appropriately.

ERRORS
       For statfs:

       ENOTDIR A  component  of  the path prefix of path is not a
               directory.

       ENAMETOOLONG
               path is too long.

       ENOENT  The file referred to by path does not exist.

       EACCES  Search permission is denied for a component of the
               path prefix of path.

       ELOOP   Too many symbolic links were encountered in trans-
               lating path.

       EFAULT  Buf or path points to an invalid address.

       EIO     An I/O error occurred while reading from or  writ-
               ing to the file system.

       ENOMEM  Insufficient kernel memory was available.

       ENOSYS  The filesystem path is on does not support statfs.

       For fstatfs:

       EBADF   fd is not a valid open file descriptor.

       EFAULT  buf points to an invalid address.

       EIO     An I/O error occurred while reading from or  writ-
               ing to the file system.

       ENOSYS  The  filesystem  fd  is  open  on does not support
               statfs.

CONFORMING TO
       4.4BSD.

SEE ALSO
       stat(2)
0
 
mitchguyAuthor Commented:
to use fstatfs I need the file descriptor. when I do a df
it gives.  
Filesystem          Mounted on
/dev/sda6 ......... /
/dev/sda1 ......... /boot
/dev/sdb  ......... /usr0

is there a way to get the file descriptor for
/dev/sdb /usr0
and is /dev/sdb always for user space?
0
 
jkrCommented:
Use 'statfs()', instead of 'fstatfs()' - as I posted above:

      int statfs(const char *path, struct statfs *buf);

It takes a path...
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

Featured Post

Cloud Class® Course: Microsoft Exchange Server

The MCTS: Microsoft Exchange Server 2010 certification validates your skills in supporting the maintenance and administration of the Exchange servers in an enterprise environment. Learn everything you need to know with this course.

  • 3
Tackle projects and never again get stuck behind a technical roadblock.
Join Now