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 and manipulates file system quotas.  A quota
     control command given by cmd operates 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 id identifier, 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 by path.  The command type
                      specifies the type of the quotas being enabled.  The addr argument
                      specifies a file from which to take the quotas.  The quota file must exist;
                      it is normally created with the quotacheck(8) program.  The id argument is
                      unused.  Only the super-user may turn quotas on.

     Q_QUOTAOFF       Disable disk quotas for the file system specified by path.  The command
                      type specifies the type of the quotas being disabled.  The addr and id
                      arguments are unused.  Only the super-user may turn quotas off.

     Q_GETQUOTASIZE   Get the wordsize used to represent the quotas for the user or group (as
                      determined by the command type).  Possible values are 32 for the old-style
                      quota file and 64 for the new-style quota file.  The addr argument is a
                      pointer to an integer into which the size is stored.  The identifier id is
                      not used.

     Q_GETQUOTA       Get disk quota limits and current usage for the user or group (as
                      determined by the command type) with identifier id.  The addr argument is a
                      pointer to a struct dqblk structure (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.  The addr argument is a pointer to a struct dqblk
                      structure (defined in <ufs/ufs/quota.h>).  The usage fields of the dqblk
                      structure 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.  The addr argument is a pointer to a struct dqblk
                      structure (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 addr arguments are ignored.

RETURN VALUES

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

ERRORS

     The quotactl() system call will fail if:

     [EOPNOTSUPP]       The kernel has not been compiled with the QUOTA option.

     [EUSERS]           The quota table cannot be expanded.

     [EINVAL]           The cmd argument or the command type is invalid.  In Q_GETQUOTASIZE,
                        Q_GETQUOTA, Q_SETQUOTA, and Q_SETUSE, quotas are not currently enabled
                        for this file system.

                        The id argument to Q_GETQUOTA, Q_SETQUOTA or Q_SETUSE is a negative
                        value.

     [EACCES]           In Q_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]            In Q_QUOTAON, either the file system on which quotas are to be enabled is
                        mounted read-only or the quota file resides on a read-only file system.

     [EIO]              An I/O error occurred while reading from or writing to a file containing
                        quotas.

     [EFAULT]           An invalid addr was supplied; the associated structure could not be
                        copied in or out of the kernel.

     [EFAULT]           The path argument points 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 in 4.3BSD-Reno.

BUGS

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