quotactl - manipulate disk quotas
int quotactl (int cmd, const char *special, int id , caddr_t
_syscall4(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 warn-
ings 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_QUOTAON Enable quotas. The addr argument is the pathname
of the file containing the quotas for the
Q_QUOTAOFF Disable quotas.
Q_GETQUOTA Get limits and current usage of disk space. The
addr argument is a pointer to a dqblk structure
(defined in <sys/quota.h>).
Q_SETQUOTA Set limits and current usage; addr is as before.
Q_SETQLIM Set limits; addr is as before.
Q_SETUSE Set usage.
Q_SYNC Sync disk copy of a filesystems quotas.
Q_GETSTATS Get collected stats.
On success, quotactl returns 0. On error, -1 is returned,
and errno is set appropriately.
ENOPKG The kernel was compiled without quota support.
EFAULT Bad addr value.
EINVAL type is not a known quota type. Or, special could
not be found.
ENOTBLK special is not a block special device.
ENODEV special cannot be found in the mount table.
EACCES The quota file is not an ordinary file.
EIO Cannot read or write the quota file.
EMFILE Too many open files: cannot open quota file.
EBUSY Q_QUOTAON was asked, but quota were enabled
ESRCH Q_GETQUOTA or Q_SETQUOTA or Q_SETUSE or Q_SETQLIM
was asked for a file system that didn't have quota
EPERM 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.
quota(1), getrlimit(2), setrlimit(2), ulimit(2), quota-