NAME    [Toc]    [Back]

       exec_with_loader - Execute a file with a loader

SYNOPSIS    [Toc]    [Back]

       int exec_with_loader(
               int flags,
               const char *loader,
               const char *file,
               char * const argv[],
               char * const envp[] );

PARAMETERS    [Toc]    [Back]

       Specifies  flags  to be passed to the loader.  Points to a
       pathname that identifies a  regular,  executable,  process
       image  file that contains the loader. This image file must
       be a nonshared image.  Points to a pathname  that  identifies
  a regular, executable process image file. This image
       file must be a call-shared image.  Specifies an  array  of
       character  pointers to null-terminated strings.  Specifies
       an array of character pointers to null-terminated strings,
       constituting the environment for the new process.

DESCRIPTION    [Toc]    [Back]

       The  exec_with_loader() function replaces the current process
 image with a new process image, in a  manner  similar
       to  what  the exec functions do. Both the loader parameter
       and the file parameter point to  pathnames  that  identify
       regular,  executable  files  called  process  image files.
       Unlike the exec functions, which construct the new process
       image  from  the  file  identified  by the file parameter,
       exec_with_loader() constructs the new process  image  from
       the file identified by the loader parameter.

                                  Note

       Throughout  this  reference page, the regular, executable,
       process image file specified by the  loader  parameter  is
       referred to as the "program loader," and the regular, executable,
 process image file specified by the file  parameter
 is referred to as the "file."

       The  loader  image  cannot  be  linked at the default user
       addresses. You must find another place  to  link  it.  One
       acceptable  place  to  link  the  loader  image  is at the
       address   space   defined   for   the   loader   in    the
       /usr/shlib/so_locations file.

       After  the  exec_with_loader() function successfully loads
       the program loader, it transfers control  to  the  program
       loader  and  effectively  passes the file parameter. Under
       normal usage, the program loader will then load (that  is,
       merge)  the file into the newly constructed process image,
       along with any object files upon which the  program  (that
       is,    the    file)    depends.   The   typical   use   of
       exec_with_loader() is to load programs that contain  unresolved
  external  references,  for  example, programs that
       require the use of a shared library.

       The exec_with_loader() function implements  and  preserves
       all  of  the semantics of the exec functions, with respect
       to the file. These include the handling of  the  argv  and
       envp  parameters, command interpreters, close-on-exec processing,
 signals, set user ID and set group ID processing,
       the process attributes and error returns.

       The  loader  parameter  may  be  null,  in  which case the
       exec_with_loader()  function  loads  the  default  program
       loader  (/sbin/loader).  The  exec_with_loader()  function
       also loads the default program loader under either of  the
       following sets of conditions, even if the loader parameter
       points to a valid program loader: If the set user ID  mode
       bit  of the file is set (see the chmod() function) and the
       owner ID of the file is not equal to the effective user ID
       of the process If the set group ID mode bit of the file is
       set and the group ID of the  file  is  not  equal  to  the
       effective group ID of the process.

       The  setting  of  the user ID or set group ID mode bits on
       the program loader have no effect whatsoever.

RETURN VALUES    [Toc]    [Back]

       If the exec_with_loader() function returns to the  calling
       process  image, an error has occurred; the return value is
       -1, and errno is set to indicate the error.

ERRORS    [Toc]    [Back]

       If the exec_with_loader() function fails, errno may be set
       to  one  of  the  following  values:  Search permission is
       denied for a directory listed in either file's  path  prefix,
 or either file denies execution permission, or either
       file is not a regular file and the implementation does not
       support  execution  of  files  of its type.  Note that the
       exec_with_loader()  function  references  two  files,  one
       specified by the loader parameter and one specified by the
       file parameter.  The length of the loader or file  parameters
  exceeds  PATH_MAX, or a pathname component is longer
       than NAME_MAX and _POSIX_NO_TRUNC is in  effect  for  that
       file.   One  or  more components of either file's pathname
       does not exist, or the loader or file parameter points  to
       an empty string. Note that the exec_with_loader() function
       references two files, one specified by the loader  parameter
  and one specified by the file parameter.  A component
       of either file's path prefix is not a directory. Note that
       the  exec_with_loader() function references two files, one
       specified by the loader parameter and one specified by the
       file  parameter.  The file specified by the loader parameter
 has the appropriate access permission but  is  not  in
       the  proper  format.   The  loader or file parameter is an
       invalid address.  Too many symbolic links were encountered
       in pathname resolution.  Insufficient memory is available.

SEE ALSO    [Toc]    [Back]

       Functions: exec(2)



                                              exec_with_loader(2)