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chown(2)                         System Calls                         chown(2)



NAME
       chown, lchown, fchown, fchownat - change owner and group of a file

SYNOPSIS
       #include <unistd.h>
       #include <sys/types.h>

       int chown(const char *path, uid_t owner, gid_t group);

       int lchown(const char *path, uid_t owner, gid_t group);

       int fchown(int fildes, uid_t owner, gid_t group);

       int  fchownat(int  fildes,  const char *path, uid_t owner, gid_t group,
       int flag);

DESCRIPTION
       The chown() function sets the owner ID and group ID of the file  speci-
       fied  by path or referenced by the open file descriptor fildes to owner
       and group respectively. If owner or group is specified as  -1,  chown()
       does not change the corresponding ID of the file.

       The  lchown() function sets the owner ID and group ID of the named file
       in the same manner as chown(), unless the  named  file  is  a  symbolic
       link. In this case, lchown() changes the ownership of the symbolic link
       file itself, while chown() changes the ownership of the file or  direc-
       tory to which the symbolic link refers.

       The  fchownat()  function  sets  the owner ID and group ID of the named
       file  in the same manner as chown(). If, however, the path argument  is
       relative,  the  path is resolved relative to the fildes argument rather
       than the current working directory.  If the  fildes  argument  has  the
       special  value  FDCWD, the path path resolution reverts back to current
       working directory relative.  If the flag argument is set to SYMLNK, the
       function  behaves  like lchown() with respect to symbolic links. If the
       path argument is absolute, the fildes argument is ignored.  If the path
       argument is a null pointer, the function behaves like fchown().

       If   chown(), lchown(), fchown(), or fchownat() is invoked by a process
       that does not have {PRIV_FILE_SETID} asserted in its effective set, the
       set-user-ID  and  set-group-ID  bits  of  the  file  mode,  S_ISUID and
       S_ISGID respectively, are cleared (see  chmod(2)). Additional  restric-
       tions apply when changing the ownership to uid 0.

       The  operating  system  defines several privileges to override restric-
       tions on the chown() family of functions.  When  the  {PRIV_FILE_CHOWN}
       privilege  is  asserted  in  the  effective set of the current process,
       there are no restrictions except in the special circumstances of chang-
       ing  ownership to or from uid 0. When the {PRIV_FILE_CHOWN_SELF} privi-
       lege is asserted, ownership changes are  restricted  to  the  files  of
       which  the  ownership  matches  the  effective  user  ID of the current
       process.  If neither privilege is asserted in the effective set of  the
       calling  process, ownership changes are limited to changes of the group
       of the file to the list of supplementary group IDs  and  the  effective
       group ID.

       The    operating    system    provides    a    configuration    option,
       {_POSIX_CHOWN_RESTRICTED}, to control the default behavior of processes
       and  the  behavior  of the NFS server.  If {_POSIX_CHOWN_RESTRICTED} is
       not in effect, the privilege {PRIV_FILE_CHOWN_SELF} is asserted in  the
       inheritable set of all processes unless overridden by policy.conf(4) or
       user_attr(4). To set this configuration option, include  the  following
       line in /etc/system:

              set rstchown = 1


       To disable this option, include the following line in  /etc/system:

              set rstchown = 0


       See system(4) and  fpathconf(2).

       Upon  successful  completion,  chown(),  fchown() and lchown() mark for
       update the st_ctime field of the file.

RETURN VALUES
       Upon successful completion, 0 is returned. Otherwise, -1  is  returned,
       the  owner  and  group of the named file remain unchanged, and errno is
       set to indicate the error.

ERRORS
       All of these functions will fail if:

       EPERM           The effective user ID does not match the owner  of  the
                       file   and   the  {PRIV_FILE_CHOWN}  privilege  is  not
                       asserted in the effective set of the  calling  process,
                       or the {PRIV_FILE_CHOWN_SELF} privilege is not asserted
                       in the effective set of the calling process.



       The chown(), lchown(), and fchownat() functions will fail if:

       EACCES          Search permission is denied on a component of the  path
                       prefix of path.



       EFAULT          The  path argument points to an illegal address and for
                       fchownat(), the file descriptor has the value AT_FDCWD.



       EINTR           A signal was caught during the execution of the chown()
                       or lchown() function.



       EINVAL          The group or owner argument is out of range.



       EIO             An  I/O error occurred while reading from or writing to
                       the file system.



       ELOOP           Too many symbolic links were encountered in translating
                       path.



       ENAMETOOLONG    The  length of the path argument exceeds {PATH_MAX}, or
                       the length of a path component exceeds {NAME_MAX} while
                       {_POSIX_NO_TRUNC} is in effect.



       ENOLINK         The  path  argument  points to a remote machine and the
                       link to that machine is no longer active.



       ENOENT          Either a component of  the  path  prefix  or  the  file
                       referred  to  by path does not exist or is a null path-
                       name.



       ENOTDIR         A component of the path prefix of path is not a  direc-
                       tory,  or  the  path supplied to fchownat() is relative
                       and the file descriptor provided does not  refer  to  a
                       valid directory.



       EROFS           The named file  resides on a read-only file system.



       The fchown() and fchownat() functions will fail if:

       EBADF           For  fchown()  the  fildes argument is not an open file
                       descriptor and.

                       For fchownat(), the path argument is not  absolute  and
                       the  fildes  argument  is  not AT_FDCWD or an open file
                       descriptor.



       EIO             An I/O error occurred while reading from or writing  to
                       the file system.



       EINTR           A signal was caught during execution of the function.



       ENOLINK         The  fildes argument points to a remote machine and the
                       link to that machine is no longer active.



       EINVAL          The group or owner argument is out of range.



       EROFS           The named file referred to by fildes resides on a read-
                       only file system.



ATTRIBUTES
       See attributes(5) for descriptions of the following attributes:


       tab()     allbox;     cw(2.750000i)|    cw(2.750000i)    lw(2.750000i)|
       lw(2.750000i).  ATTRIBUTE TYPEATTRIBUTE  VALUE  Interface  StabilitySee
       below.  MT-LevelSee below.


       The  chown(), fchown(), and lchown() functions are Standard. The fchow-
       nat() function is Evolving.

       The chown() and fchownat() functions are Async-Signal-Safe.

SEE ALSO
       chgrp(1), chown(1), chmod(2), fpathconf(2), system(4), attributes  (5),
       standards(5)




SunOS 5.10                        20 Jan 2003                         chown(2)