3474 tar should support -C on extract
Reviewed by: Robert Mustacchi <rm@joyent.com>

*** 19,28 ****
--- 19,29 ----
   * CDDL HEADER END
   */
  /*
   * Copyright (c) 1988, 2010, Oracle and/or its affiliates. All rights reserved.
   * Copyright 2012 Milan Jurik. All rights reserved.
+  * Copyright (c) 2013, Joyent, Inc. All rights reserved.
   */
  
  /*      Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T     */
  /*        All Rights Reserved   */
  
*** 559,568 ****
--- 560,570 ----
  static void detect_compress(void);
  
  static  struct stat stbuf;
  
  static  char    *myname;
+ static  char    *xtract_chdir = NULL;
  static  int     checkflag = 0;
  static  int     Xflag, Fflag, iflag, hflag, Bflag, Iflag;
  static  int     rflag, xflag, vflag, tflag, mt, svmt, cflag, mflag, pflag;
  static  int     uflag;
  static  int     errflag;
*** 1136,1147 ****
--- 1138,1163 ----
                                  } else {
                                          Iflag = 1;
                                          argv[argc] = argv[argc+2];
                                          build_table(include_tbl, argv[++argc]);
                                  }
+                         } else if (strcmp(argv[argc], "-C") == 0) {
+                                 if (!argv[argc+1]) {
+                                         (void) fprintf(stderr, gettext("tar: "
+                                             "missing argument for -C flag\n"));
+                                         done(2);
+                                 } else if (xtract_chdir != NULL) {
+                                         (void) fprintf(stderr, gettext("tar: "
+                                             "extract should have only one -C "
+                                             "flag\n"));
+                                         done(2);
+                                 } else {
+                                         argv[argc] = argv[argc+2];
+                                         xtract_chdir = argv[++argc];
                                  }
                          }
+                 }
                  if (strcmp(usefile, "-") == 0) {
                          mt = dup(0);
                          ++bflag;
                          /* try to recover from short reads when reading stdin */
                          ++Bflag;
*** 1156,1165 ****
--- 1172,1187 ----
                                  pid = uncompress_file();
                                  wait_pid(pid);
                          }
                  }
                  if (xflag) {
+                         if (xtract_chdir != NULL) {
+                                 if (tar_chdir(xtract_chdir) < 0) {
+                                         vperror(1, gettext("can't change "
+                                             "directories to %s"), xtract_chdir);
+                                 }
+                         }
                          if (Aflag && vflag)
                                  (void) printf(gettext(
                                      "Suppressing absolute pathnames.\n"));
  
                          doxtract(argv);