Add remap translator

* trans/remap.c: New file.
* trans/Makefile (targets): Add remap.
(SRCS): Add remap.c.
(remap): Add rule.
* utils/remap.sh: New script.
* utils/Makefile (targets): Add remap.
(special-targets): Add remap.
(SRCS): Add remap.sh.
* NEWS: Advertise new translator

2 files changed, 155 insertions, 2 deletions

diff --git a/trans/Makefile b/trans/Makefile
index ff5a6a65..b3210b67 100644
--- a/trans/Makefile
+++ b/trans/Makefile
@@ -20,10 +20,10 @@ dir := trans
 makemode := servers
 
 targets = symlink firmlink ifsock magic null fifo new-fifo fwd crash \
-	  password hello hello-mt streamio fakeroot proxy-defpager
+	  password hello hello-mt streamio fakeroot proxy-defpager remap
 SRCS = ifsock.c symlink.c magic.c null.c fifo.c new-fifo.c fwd.c \
 	crash.c firmlink.c password.c hello.c hello-mt.c streamio.c \
-	fakeroot.c proxy-defpager.c
+	fakeroot.c proxy-defpager.c remap.c
 OBJS = $(SRCS:.c=.o) fsysServer.o ifsockServer.o passwordServer.o \
 	crashServer.o crash_replyUser.o msgServer.o \
 	default_pagerServer.o default_pagerUser.o \
@@ -50,6 +50,7 @@ hello-mt magic null ifsock fifo new-fifo firmlink: ../libtrivfs/libtrivfs.a ../l
 magic: ../libiohelp/libiohelp.a
 hello: ../libtrivfs/libtrivfs.a ../libfshelp/libfshelp.a ../libports/libports.a ../libihash/libihash.a
 fakeroot: ../libnetfs/libnetfs.a ../libfshelp/libfshelp.a ../libiohelp/libiohelp.a ../libports/libports.a ../libihash/libihash.a
+remap: ../libtrivfs/libtrivfs.a ../libfshelp/libfshelp.a ../libports/libports.a ../libihash/libihash.a
 $(targets): ../libshouldbeinlibc/libshouldbeinlibc.a
 
 $(targets): %: %.o
diff --git a/trans/remap.c b/trans/remap.c
new file mode 100644
index 00000000..5ee01891
--- /dev/null
+++ b/trans/remap.c
@@ -0,0 +1,152 @@
+/* remap -- a translator for changing paths
+   Copyright (C) 2013 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2, or (at
+   your option) any later version.
+
+   This program is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
+
+#include <hurd/trivfs.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <argp.h>
+#include <error.h>
+#include <string.h>
+
+#include <version.h>
+
+int trivfs_fstype = FSTYPE_MISC;
+int trivfs_fsid = 0;
+int trivfs_support_read = 0;
+int trivfs_support_write = 0;
+int trivfs_support_exec = 0;
+int trivfs_allow_open = 0;
+
+void
+trivfs_modify_stat (struct trivfs_protid *cred, struct stat *st)
+{
+  /* Don't care */  
+}
+
+error_t
+trivfs_goaway (struct trivfs_control *cntl, int flags)
+{
+  exit (0);
+}
+
+struct remap
+{
+  char *from;
+  char *to;
+  struct remap *next;
+};
+
+static struct remap *remaps;
+
+error_t
+trivfs_S_dir_lookup (struct trivfs_protid *diruser,
+		     mach_port_t reply, mach_msg_type_name_t reply_type,
+		     char *filename,
+		     int flags,
+		     mode_t mode,
+		     retry_type *do_retry,
+		     char *retry_name,
+		     mach_port_t *retry_port,
+		     mach_msg_type_name_t *retry_port_type)
+{
+  struct remap *remap;
+
+  if (!diruser)
+    return EOPNOTSUPP;
+
+  for (remap = remaps; remap; remap = remap->next)
+    if (!strcmp (remap->from, filename))
+      {
+#ifdef DEBUG
+	fprintf (stderr,"replacing %s with %s\n", remap->from, remap->to);
+	fflush (stderr);
+#endif
+	filename = remap->to;
+	break;
+      }
+
+  *do_retry = FS_RETRY_REAUTH;
+  *retry_port = getcrdir ();
+  *retry_port_type = MACH_MSG_TYPE_COPY_SEND;
+  strcpy (retry_name, filename);
+
+  return 0;
+}
+
+static error_t
+parse_opt (int key, char *arg, struct argp_state *state)
+{
+  static char *remap_from;
+
+  switch (key)
+  {
+    case ARGP_KEY_ARG:
+
+      /* Skip heading slashes */
+      while (arg[0] == '/')
+        arg++;
+
+      if (!remap_from)
+	/* First of a pair */
+	remap_from = strdup (arg);
+      else
+	{
+	  /* Second of a pair */
+	  struct remap *remap = malloc (sizeof (*remap));
+	  remap->from = remap_from;
+	  remap->to = strdup (arg);
+	  remap->next = remaps;
+#ifdef DEBUG
+	  fprintf (stderr, "adding remap %s->%s\n", remap->from, remap->to);
+#endif
+	  remaps = remap;
+	  remap_from = NULL;
+	}
+
+      break;
+  }
+  return 0;
+}
+
+const char *argp_program_version = STANDARD_HURD_VERSION (fakeroot);
+
+int
+main (int argc, char **argv)
+{
+  error_t err;
+  mach_port_t bootstrap;
+
+  struct argp argp = { NULL, parse_opt, "[ FROM1 TO1 [ FROM2 TO2 [ ... ] ] ]", "\
+A translator for remapping directories.\v\
+This translator is to be used as a chroot, within which paths point to the\
+same files as the original root, except a given set of paths, which are\
+remapped to given paths." };
+
+  argp_parse (&argp, argc, argv, ARGP_IN_ORDER, 0, 0);
+
+  task_get_bootstrap_port (mach_task_self (), &bootstrap);
+  struct trivfs_control *fsys;
+
+  err = trivfs_startup (bootstrap, 0, 0, 0, 0, 0, &fsys);
+  if (err)
+    error (1, err, "trivfs_startup failed");
+  ports_manage_port_operations_one_thread (fsys->pi.bucket, trivfs_demuxer, 0);
+
+  /*NOTREACHED*/
+  return 0;
+}