set_usage - checks whether a disk partition is in use and
sets the fstype of the partition in the disk label
#include <sys/disklabel.h> #include <overlap.h>
int set_usage(
const char *special,
int fstype,
int Force );
Filesystem Library (libfilsys.a)
Shared Filesystem Library (libfilsys.so)
Points to a special device file. The file system type
(fstype) to set for the application in the disk label.
For example, UFS uses FS_BSDFFS and databases use FS_DB.
See <sys/disklabel.h> for a list of the supported file
system types. When the application wants to override a
failure in the usage checks and set the fstype, Force is
set to 1.
The set_usage() function checks whether the special device
file is in use, that is, whether it contains a valid file
system, is part of LSM, or is being used by a database or
for swap space. It also checks that the range of blocks to
be used does not overlap with blocks that are already in
use or marked to be in use. If the checks succeed, this
function then sets the fstype for the partition in the
disk label. If the checks do not succeed, the fstype is
not modified and an error is returned. The Force parameter
can be set, so that the function overrides a failure
in the usage checking and modifies the file system type.
Note that if the specified partition or an overlapping
partition is open, the Force parameter cannot override the
usage checking.
Before allocating a partition, an application should check
that none of the overlapping partitions is in use. When an
application uses a partition, it should mark its use by
setting the fstype field in the partition map in the disk
label. The fstypes that can be set are listed in
<sys/disklabel.h>.
The set_usage() function returns the following values.
Logical names for the return values are listed in parentheses.
The checks succeeds (that is, the specified range
of blocks is not open or marked for use), and the fstype
field for the specified special device file was set. The
fstype field could not be modified because either the
specified partition or another overlapping partition is in
use. This error cannot be overridden by the Force parameter.
Either the special device file is invalid or the
device cannot be opened. This error cannot be overridden
by the Force parameter. When Force is 0, this value is
returned to indicate that one or more other partitions
overlap with the specified special device file. When Force
is 1, this value indicates that any overlapping partitions
that are marked for use will be modified to the FS_UNUSED
type. The return value will then be 0. The specified partition
and overlapping partitions have the fstype field
set. When Force is 1, the overlapping partitions will be
modified to the FS_UNUSED type. The return value will then
be 0. The disk label is not present or is corrupted. An
error was encountered during the checks. Either /etc/fdmns
or /etc/fdmns/domain for an in-use domain does not exist
or is corrupted. An error was encountered during the
checks. The special device file for an in-use swap device
does not exist. This indicates a failure in updating the
disk label. When Force is 0, this value indicates that
the specified special device file is marked for use. The
return value will be the fstype set for the partition.
Refer to <sys/disklabel.h> to determine the fstype that
corresponds to the return value.
When Force is 1, this value indicates that any
overlapping partitions that are marked for use will
be modified to the FS_UNUSED type. The return value
will then be 0.
The following program illustrates the use of set_usage()
and the possible error messages based on return values
from set_usage().
#define DKTYPENAMES #include <stdio.h> #include
<sys/disklabel.h> #include <overlap.h>
#define STR_ERR_OPEN \
"Error: %s is open and in use.\n"
#define STR_ERR_OPEN_OVERLAP \
"Error: Partition overlapping %s is open and in
use.\n"
#define STR_ERR_INVALID_DEV \
"Error: %s is an invalid device or cannot be
opened.\n"
#define STR_ERR_DEFAULT_FSTYPE \
"Error: %s is marked in the disk label as in use by
%s.\n"
#define STR_WARN_FSTYPE_OVERLAP \
"Warning: partition(s) which overlaps %s are marked in
use.\n"
#define STR_WARN_MULT_OVERLAP \
"Warning: %s and overlapping partition(s) are marked
in use.\n"
#define STR_WARN_INVAL_DISKLBL \
"Warning: the disklabel for %s does not exist or is
corrupted.\n"
int mark_usage(char *special, int fstype) {
int ret;
int force = 0;
void do_interactive(char *);
ret = set_usage(special, fstype, force);
if (ret == 0) {
/*
* Specified partition is available for use and
* has been marked in use by "fstype".
*/
return (0);
}
switch (ret) {
case OV_ERR_OPEN_OVERLAP:
/*
* Check if the specified partition is open.
*/
ret = check_usage(special, OV_CHECK_EXACT);
if (ret == OV_ERR_OPEN_OVERLAP)
fprintf(stderr, STR_ERR_OPEN, special);
else
fprintf(stderr, STR_ERR_OPEN_OVERLAP, special);
return (-1);
case OV_ERR_INVALID_DEV:
fprintf(stderr, STR_ERR_INVALID_DEV, special);
return (-1);
case OV_ERR_INVALID_DSKLBL:
fprintf(stderr, STR_WARN_INVAL_DISKLBL, special);
return (-1);
case OV_ERR_FSTYPE_OVERLAP:
fprintf(stderr, STR_WARN_FSTYPE_OVERLAP, special);
/*
* Check if the user overrides the warning.
*/
do_interactive(special);
force = 1;
ret = set_usage(special, fstype, force);
break;
case OV_ERR_MULT_FSTYPE_OVERLAP:
fprintf(stderr, STR_WARN_MULT_OVERLAP, special);
/*
* Check if the user overrides the warning.
*/
do_interactive(special);
force = 1;
ret = set_usage(special, fstype, force);
break;
}
return (-1); }
void do_interactive(char *special) {
int c;
/*
* Check if stdin is a terminal.
*/
if ( !(isatty(fileno(stdin))) ) {
exit(1);
}
do {
printf("CONTINUE? [y/n] ");
(void) fflush(stdout);
/* read input */
c = getc(stdin);
/* Skips over all chars which are not CR. Only
* the first character typed is significant.
*/
while (c!='\n' && getc(stdin)!='\n'){
}
if(c == 'n' || c == 'N')
exit(2);
} while (c!='y' && c!='Y');
return; }
Commands: mkfdmn(8), newfs(8), voldisk(8), swapon(8)
Functions: check_usage(3)
set_usage(3)
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