Message-Id:	<199904252128.VAA51774@out4.ibm.net>
From:	"Mark E." <snowball3 AT usa DOT net>
To:	djgpp-workers AT delorie DOT com
Date:	Sun, 25 Apr 1999 17:29:32 -0400
MIME-Version:	1.0
Subject:	Re: fsext patches for dup and dup2
X-mailer:	Pegasus Mail for Win32 (v3.01d)
Reply-To:	djgpp-workers AT delorie DOT com

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> True, it won't work for fsext allocated handles. But when fsext is used to
> keep state information about a actual handle (e.g. for emulating the
> pipes), then adding fsext code to dup & dup2 is essential for the
> emulation to work properly...

Since the only good use of adding fsext code to dup{2} is to let the fsext 
handler update state information, then they should be modified to 
provide it after getting the new handle, rather than make the fsext 
handler get the value itself by yet another call to dup{2}. See the 
attached patch for my revised patch.

Mark

--- 
Mark Elbrecht, snowball3 AT usa DOT net
http://snowball.frogspace.net/


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Index: djgpp/src/libc/posix/unistd/dup.c
===================================================================
RCS file: /cvs/djgpp/djgpp/src/libc/posix/unistd/dup.c,v
retrieving revision 1.1
diff -c -3 -r1.1 dup.c
*** dup.c	1995/02/27 00:43:08	1.1
--- dup.c	1999/04/25 21:21:28
***************
*** 5,15 ****
--- 5,18 ----
  #include <errno.h>
  #include <io.h>
  #include <libc/dosio.h>
+ #include <sys/fsext.h>
  
  int
  dup(int fd)
  {
    __dpmi_regs r;
+   __FSEXT_Function *func;
+ 
    r.h.ah = 0x45;
    r.x.bx = fd;
    __dpmi_int(0x21, &r);
***************
*** 18,23 ****
--- 21,41 ----
      errno = __doserr_to_errno(r.x.ax);
      return -1;
    }
+ 
+   /* Give a FSEXT handler a chance to update the state data
+      associated with the two handles. */
+   func = __FSEXT_get_function(fd);
+   if (func)
+   {
+     int rv;
+     int fds[2];
+     fds[0] = fd;
+     fds[1] = r.x.ax;
+     /* Indicate __FSEXT_dup2 since we already have the duplicated handle. */
+     if (func(__FSEXT_dup2, &rv, fds))
+       return rv;
+   }
+ 
    setmode(r.x.ax, __file_handle_modes[fd]);
    return r.x.ax;
  }
Index: djgpp/src/libc/posix/unistd/dup.c
===================================================================
RCS file: /cvs/djgpp/djgpp/src/libc/posix/unistd/dup.c,v
retrieving revision 1.1
diff -c -3 -r1.1 dup.c
*** dup.c	1995/02/27 00:43:08	1.1
--- dup.c	1999/04/25 21:21:38
***************
*** 5,15 ****
--- 5,18 ----
  #include <errno.h>
  #include <io.h>
  #include <libc/dosio.h>
+ #include <sys/fsext.h>
  
  int
  dup(int fd)
  {
    __dpmi_regs r;
+   __FSEXT_Function *func;
+ 
    r.h.ah = 0x45;
    r.x.bx = fd;
    __dpmi_int(0x21, &r);
***************
*** 18,23 ****
--- 21,41 ----
      errno = __doserr_to_errno(r.x.ax);
      return -1;
    }
+ 
+   /* Give a FSEXT handler a chance to update the state data
+      associated with the two handles. */
+   func = __FSEXT_get_function(fd);
+   if (func)
+   {
+     int rv;
+     int fds[2];
+     fds[0] = fd;
+     fds[1] = r.x.ax;
+     /* Indicate __FSEXT_dup2 since we already have the duplicated handle. */
+     if (func(__FSEXT_dup2, &rv, fds))
+       return rv;
+   }
+ 
    setmode(r.x.ax, __file_handle_modes[fd]);
    return r.x.ax;
  }

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