preroot.3

Introduction to Library Functions                      PREROOT(3)

NAME
     preroot - preroot support

SYNOPSIS
          #include <preroot.h>

          char*    getpreroot(char* path, char* cmd);
          int      ispreroot(char* dir);
          int      realopen(char* path, int mode, int perm);
          void     setpreroot(char** argv, char* dir);

DESCRIPTION
     The  preroot  routines  manipulate  the   process   preroot.
     preroot   is   a  kernel  supported  per-process  two  level
     viewpath.  All pathnames rooted at / are first searched  for
     in the process preroot directory and then in the system root
     directory.  Setting the  process  preroot  is  a  priveleged
     operation controlled by the /etc/preroot(1) command.

     <preroot.h> defines the symbol FS_PREROOT for those  systems
     that support preroot.  The following routines are valid only
     when FS_PREROOT is defined:

     getpreroot
          returns a pointer  to  the  absolute  pathname  of  the
          preroot  directory  for the executable cmd.  The result
          is placed in path.  If path is 0 then malloc(3) is used
          to  allocate  the pathname space.  0 is returned if cmd
          has no preroot or if an error was encountered.  In this
          case errno is set to indicate the error.

     ispreroot
          Non-zero is returned if  dir  is  the  current  process
          preroot.   If dir is 0 then non-zero is returned if the
          current process has a preroot.

     realopen
          temporarily disables the process preroot  and  does  an
          open(3)  relative  to  the  system root directory.  The
          return value from open is returned.   If  there  is  no
          preroot then realopen is equivalent to open.

     setpreroot
          calls execvp(3) as execvp(argv[0],argv) with  the  pro-
          cess  preroot  set to dir.  argv must be a 0-terminated
          argument array.   If  argv  is  0  then  the  value  of
          opt_argv  from  optget(3)  is used.  setpreroot returns
          immediately if dir is already the process preroot.

SEE ALSO
     /etc/preroot(1)

SunOS 5.10                Last change:                          1

Introduction to Library Functions                      PREROOT(3)

BUGS
     Preroot semantics should be preserved  when  reading  direc-
     tories.   The  ast  directory(3)  routines  do  this.  3d(1)
     viewpathing does preroot the right way.

SunOS 5.10                Last change:                          2

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