Index for Section 2

Alphabetical listing for C

Bottom of page

chown(2)
NAME
  chown, lchown, fchown - Change the owner and group IDs of a file

SYNOPSIS
  #include <unistd.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 filedes,
	  uid_t owner,
	  gid_t group );

STANDARDS
  Interfaces documented on this reference page conform to industry standards
  as follows:

  chown(): POSIX.1, XSH4.0, XSH4.2, XSH5.0

  fchown(): POSIX.1, XSH4.2, XSH5.0

  lchown(): POSIX.1, XSH4.2, XSH5.0

  Refer to the standards(5) reference page for more information about
  industry standards and associated tags.

PARAMETERS
  path
      Specifies the name of the file whose owner ID, group ID, or both are to
      be changed. When the path parameter refers to a symbolic link, the
      behaviors of the chown() and the lchown() functions differ. The chown()
      function changes the ownership of the file pointed to by the symbolic
      link. The lchown() function changes the ownership of the symbolic link
      file itself.

  filedes
      Specifies a valid open file descriptor.

  owner
      Specifies a numeric value representing the owner ID.

  group
      Specifies a numeric value representing the group ID.

DESCRIPTION
  The chown(), lchown() and fchown() functions change the owner and group of
  a file.

  A process can change the value of the owner ID of a file only if the
  process has superuser privilege.  A process without superuser privilege can
  change the group ID of a file only to the value of its effective group ID
  or to a value in its supplementary group list.

  If the value of the owner ID is changed and the process does not have
  superuser privilege, the set-user ID attribute (the S_ISUID bit) of a
  regular file is cleared.

  The set-user ID attribute (S_ISUID bit) of a file is cleared upon
  successful return if:

    ·  The file is a regular file.

    ·  The process does not have superuser privilege.

  The set-group ID attribute (S_ISGID bit) of a file is cleared upon
  successful return if:

    ·  The file is a regular file.

    ·  The process does not have superuser privilege.

  If the owner or group parameter is specified as (uid_t)-1 or (gid_t)-1
  respectively, the corresponding ID of the file is unchanged.

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

RETURN VALUES
  Upon successful completion, the chown(), lchown(), and fchown() functions
  return a value of 0 (zero). Otherwise, a value of -1 is returned, the owner
  and group of the file remain unchanged, and errno is set to indicate the
  error.

ERRORS
  If the chown() or lchown() functions fails, errno may be set to one of the
  following values:

  [EACCES]
      Search permission is denied on a component of path.

  [EFAULT]
      The path parameter is an invalid address.

  [EINVAL]
      The owner or group ID is not a value supported by this implementation.

  [ELOOP]
      Too many links were encountered in translating path.

  [ENAMETOOLONG]
      The length of the path argument exceeds PATH_MAX or a pathname
      component is longer than NAME_MAX.

  [ENOTDIR]
      A component of path is not a directory.

  [ENOENT]
      The path parameter does not exist or is an empty string.

  [EPERM]
      The effective user ID does not match the ID of the owner of the file,
      and the calling process does not have appropriate privilege and
      _POSIX_CHOWN_RESTRICTED indicates that such privilege is required.

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

  [ESTALE]
      The process' root or current directory is located in a virtual file
      system that has been unmounted.

  If the fchown() function fails, errno may be set to one of the following
  values:

  [EBADF]
      The file descriptor filedes is not valid.

  [EINVAL]
      The owner or group ID is not a value supported by this implementation.

SEE ALSO
  Functions: chmod(2)

  Commands: chown(1)

  Others:: standards(5)

Index for Section 2

Alphabetical listing for C

Top of page