NAME¶

quotactl—manipulate file system quotas

LIBRARY¶

Standard C Library (libc, -lc)

SYNOPSIS¶

#include<sys/types.h>
#include<ufs/ufs/quota.h> int
quotactl(const char *path,int cmd,int id,void *addr);

DESCRIPTION¶

The quotactl()system call enables, disables andmanipulates file system quotas. A quota control command given by cmdoperates on the given filename path for the given user or group id.(NOTE: One should use the QCMD macro defined in<ufs/ufs/quota.h>to formulate the value for cmd.)The address of an optional command specific data structure, addr,may be given; its interpretation is discussed below with each command. For commands that use the ididentifier, it must be either -1 or any positive value. The value of -1 indicates that the current UID or GID should be used. Any other negative value will return an error. Currently quotas are supported only for the “ufs”file system.For“ufs”,a command is composed of a primary command (see below) and a command type used to interpret the id.Types are supported for interpretation of user identifiers (USRQUOTA) and group identifiers (GRPQUOTA). The “ufs”specific commands are:

Q_QUOTAON

Enable disk quotas for the file system specified bypath.The command type specifies the type of the quotas being enabled. The addrargument specifies a file from which to take the quotas. The quota file must exist; it is normally created with the quotacheck(8)program.Theidargument is unused. Only the super-user may turn quotas on.

Q_QUOTAOFF

Disable disk quotas for the file system specified bypath.The command type specifies the type of the quotas being disabled. The addrandid arguments are unused. Only the super-user may turn quotas off.

Q_GETQUOTA

Get disk quota limits and current usage for the user or group (as determined by the command type) with identifier id.Theaddrargumentis a pointer to a structdqblkstructure (defined in<ufs/ufs/quota.h>).

Q_SETQUOTA

Set disk quota limits for the user or group(as determined by the command type) with identifier id.Theaddrargumentis a pointer to a structdqblkstructure (defined in<ufs/ufs/quota.h>).The usage fields of the dqblkstructure are ignored.This system call is restricted to the super-user.

Q_SETUSE

Set disk usage limits for the user or group(as determined by the command type) with identifier id.Theaddrargumentis a pointer to a structdqblkstructure (defined in<ufs/ufs/quota.h>).Only the usage fields are used. This system call is restricted to the super-user.

Q_SYNC

Update the on-disk copy of quota usages.The command type specifies which type of quotas are to be updated. The id and addrarguments are ignored.

RETURN VALUES¶

The quotactl()function returnsthe value 0 if successful;otherwise the value -1 is returned and the global variable errnois set to indicate the error.

ERRORS¶

The quotactl()system call will fail if:

[EOPNOTSUPP]

The kernel has not been compiled with theQUOTA option.

[EUSERS]

The quota table cannot be expanded.

[EINVAL]

Thecmdargumentor the command type is invalid. In Q_GETQUOTAandQ_SETQUOTA,quotas are not currently enabled for this file system.

The idargument toQ_GETQUOTA,Q_SETQUOTAorQ_SETUSEis a negative value.

[EACCES]

InQ_QUOTAON,the quota file is not a plain file.

[EACCES]

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

[ENOTDIR]

A component of a path prefix was not a directory.

[ENAMETOOLONG]

A component of either pathname exceeded 255 characters,or the entire length of either path name exceeded 1023 characters.

[ENOENT]

A filename does not exist.

[ELOOP]

Too many symbolic links were encountered in translating a pathname.

[EROFS]

InQ_QUOTAON,the quota file resides on a read-only file system.

[EIO]

AnI/Oerror occurred while reading from or writingto a file containing quotas.

[EFAULT]

An invalidaddrwas supplied; the associated structure could not be copied in or out of the kernel.

[EFAULT]

Thepathargumentpoints outside the process's allocated address space.

[EPERM]

The call was privileged and the caller was not the super-user.

SEE ALSO¶

quota(1),fstab(5),edquota(8),quotacheck(8),quotaon(8),repquota(8)

HISTORY¶

The quotactl()system call appeared in4.3BSD-Reno.

BUGS¶

There should be some way to integrate this call with the resource limit interface provided by setrlimit(2)andgetrlimit(2).