The common usage of the library will look as follows: The program calls
the function get_resources first; this function fills the given
structure with information about present hard disks and their partition
structure. For some of the partitions will be called function
get_rootdirs to obtain the list of their root-subdirectories. Then
the program calls function commit_disks with parameters describing
new partition structures on the disks and data location for new
partitions. If there are demands conflicting with possibilities of the
library (e.g. there is too much data to move to a small partition) then
the function will return the list of such encountered conflicts and
refuses to continue the operation.
get_resources()This function is used to get information about all disks and filesystems
in the system. It is also possible to provide as a parameter
us_sp_devices a list of file names to check
for partition tables and filesystems. The list is terminated by an empty
string. It is also possible to provide as us_sp_devices NULL pointer
in case that there are no additional files to check.
Its prototype is following:
int get_resources(struct resources *,char **us_sp_devices, ERR_PARAM);
After successful call (see
Error handling) the struct resources is filled in. This structure
contains array of all drives detected on the system, array of all
supported global parameters, and arrays of all filesystem specific
parameters (one array for each supported filesystem). See
Filesystem specific and global parameters for
parameter description.
For each detected drive there is (in struct disk_info) some
`technical' information like drive type or geometry (see lib.h
for details) and an array of struct user_partition with information
for each partition on the drive. struct user_partition contains:
up_base),up_entry) and
its validity flag (up_entryvalid)get_resources() itself.
get_rootdirs()
int get_rootdirs(struct user_partition *part, ERR_PARAM);
Function get_rootdirs expands information about directories
contained in struct user_partition; it deallocates the one-member
array up_dirs allocated by get_resources() and allocates a new
one of length equal to up_dircount; up_dircount is set to the
number of root subdirectories increased by one. Function
get_rootdirs will not be supported in the first versions of the
library.
See Data structures used for data location for description of array of directories.
commit_disks()
int commit_disks(struct final *, int check_only, ERR_PARAM);
commit_disks() is The Function. It gets struct final
with description of current partitions and filesystems and also with
description of desired situation after conversion. Some global
parameters can be also specified in struct final. If
check_only is set, only checks are performed and result is
returned.
As current as desired configuration of partitions is specified by an
array of struct disk_info. Each struct describes layout of one
disk.
For description of how disk layout is specified see
get_resources() (the current layout given to commit_disks()
should be the same as returned by get_resources() and the future
layout should have the `same form'). See
Filesystem specific and global parameters for instructions how
to alter filesystem parameters.
Note that record struct part_entry up_entry (ondisk format of
partition entry) in struct user_partition can be left unfilled if
corresponding flag (up_entryvalid) set to appropriate value (zero).
In that case needed values are computed by library itself from
struct partition_base.