MFC:

- In pipe() return the error returned by pipe_create(), rather then
    hardcoded ENFILES, which is incorrect. pipe_create() can fail due
    to ENOMEM.
  - Update manual page, describing ENOMEM return code.

  Reviewed by:    arch

lib/libc/sys/pipe.2

@@ -32,7 +32,7 @@
 .\"     @(#)pipe.2	8.1 (Berkeley) 6/4/93
 .\" $FreeBSD$
 .\"
-.Dd June 4, 1993
+.Dd January 30, 2006
 .Dt PIPE 2
 .Os
 .Sh NAME
@@ -98,6 +98,8 @@ system call will fail if:
 Too many descriptors are active.
 .It Bq Er ENFILE
 The system file table is full.
+.It Bq Er ENOMEM
+Not enough kernel memory to establish a pipe.
 .It Bq Er EFAULT
 The
 .Fa fildes

sys/kern/sys_pipe.c

@@ -357,10 +357,11 @@ pipe(td, uap)
 	    NULL);
 
 	/* Only the forward direction pipe is backed by default */
-	if (pipe_create(rpipe, 1) || pipe_create(wpipe, 0)) {
+	if ((error = pipe_create(rpipe, 1)) != 0 ||
+	    (error = pipe_create(wpipe, 0)) != 0) {
 		pipeclose(rpipe);
 		pipeclose(wpipe);
-		return (ENFILE);
+		return (error);
 	}
 
 	rpipe->pipe_state |= PIPE_DIRECTOK;