quotactl — manipulate disk quota
#include <sys/types.h> #include <sys/quota.h>
int
quotactl( |
int | cmd, |
| const char * | special, | |
| int | id, | |
| caddr_t | addr); |
The quota system defines for each user and/or group a soft limit and a hard limit bounding the amount of disk space that can be used on a given file system. The hard limit cannot be crossed. The soft limit can be crossed, but warnings will ensue. Moreover, the user cannot be above the soft limit for more than one week (by default) at a time: after this week the soft limit counts as hard limit.
The quotactl() system call
manipulates these quota. Its first argument is of the form
QCMD(subcmd, type) where type is either USRQUOTA or GRPQUOTA (for user quota and group quota,
respectively), and subcmd is described
below.
The second argument special is the block special
device these quota apply to. It must be mounted.
The third argument id is the user or group ID
these quota apply to (when relevant).
The fourth argument addr is the address of a data
structure, depending on the command.
The subcmd is
one of
Q_QUOTAONEnable quota. The addr argument is the
pathname of the file containing the quota for the
filesystem.
Q_QUOTAOFFDisable quota.
Q_GETQUOTAGet limits and current usage of disk space. The
addr argument
is a pointer to a dqblk structure (defined in
<sys/quota.h>).
Q_SETQUOTASet limits and current usage; addr is as before.
Q_SETQLIMSet limits; addr is as before.
Q_SETUSESet usage.
Q_SYNCSync disk copy of a filesystem's quota.
Q_GETSTATSGet collected stats.
On success, quotactl()
returns 0. On error, −1 is returned, and errno is set appropriately.
The quota file is not an ordinary file.
Q_QUOTAON was asked,
but quotas were enabled already.
Bad addr
value.
type is
not a known quota type. Or, special could not be
found.
Cannot read or write the quota file.
Too many open files: cannot open quota file.
special
cannot be found in the mount table.
The kernel was compiled without quota support.
special is
not a block special device.
The process was not root (for the file system), and
Q_GETQUOTA was asked for
another id than
that of the process itself, or anything other than
Q_GETSTATS or
Q_SYNC was asked.
Q_GETQUOTA or
Q_SETQUOTA or
Q_SETUSE or Q_SETQLIM was asked for a file system
that didn't have quota enabled.
quota(1), getrlimit(2), setrlimit(2), ulimit(3), quotacheck(8), quotaon(8)
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