Adding upstream version 4.6.2.upstream/4.6.2upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1147 insertions, 0 deletions

diff --git a/acls.c b/acls.c
new file mode 100644
index 0000000..514e0fc
--- /dev/null
+++ b/acls.c
@@ -0,0 +1,1147 @@
+/* Copyright (c) 2008, 2009
+ *      Juergen Weigert (jnweiger@immd4.informatik.uni-erlangen.de)
+ *      Michael Schroeder (mlschroe@immd4.informatik.uni-erlangen.de)
+ *      Micah Cowan (micah@cowan.name)
+ *      Sadrul Habib Chowdhury (sadrul@users.sourceforge.net)
+ * Copyright (c) 1993-2002, 2003, 2005, 2006, 2007
+ *      Juergen Weigert (jnweiger@immd4.informatik.uni-erlangen.de)
+ *      Michael Schroeder (mlschroe@immd4.informatik.uni-erlangen.de)
+ * Copyright (c) 1987 Oliver Laumann
+ *
+ * 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 3, 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 (see the file COPYING); if not, see
+ * http://www.gnu.org/licenses/, or contact Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02111-1301  USA
+ *
+ ****************************************************************
+ */
+
+#include "config.h"
+
+#include <sys/types.h>
+
+/* XXX: WHY IS THIS HERE?? :XXX */
+
+#ifdef CHECKLOGIN
+# ifdef _SEQUENT_
+#  include <stdio.h>	/* needed by <pwd.h> */
+# endif /* _SEQUENT_ */
+# include <pwd.h>
+# ifdef SHADOWPW
+#  include <shadow.h>
+# endif /* SHADOWPW */
+#endif /* CHECKLOGIN */
+
+#ifndef NOSYSLOG
+# include <syslog.h>
+#endif
+
+#include "screen.h"	/* includes acls.h */
+#include "extern.h"
+
+
+/************************************************************************
+ * user managing code, this does not really belong into the acl stuff   *
+ ************************************************************************/
+
+extern struct comm comms[];
+extern struct win *windows, **wtab;
+extern char NullStr[];
+extern char SockPath[];
+extern struct display *display, *displays;
+struct acluser *users;
+
+#ifdef MULTIUSER
+int maxusercount = 0;	/* used in process.c: RC_MONITOR, RC_SILENCE */
+
+/* record given user ids here */
+static AclBits userbits;
+
+/*
+ * rights a new unknown user will have on windows and cmds. 
+ * These are changed by a "umask ?-..." command: 
+ */
+static char default_w_bit[ACL_BITS_PER_WIN] = 
+{ 
+  1,	/* EXEC */
+  1, 	/* WRITE */
+  1 	/* READ */
+};
+
+static char default_c_bit[ACL_BITS_PER_CMD] = 
+{ 
+  0	/* EXEC */
+};
+
+/* rights of all users per newly created window */
+/*
+ * are now stored per user (umask)
+ * static AclBits default_w_userbits[ACL_BITS_PER_WIN];
+ * static AclBits default_c_userbits[ACL_BITS_PER_CMD];
+ */
+
+static int GrowBitfield __P((AclBits *, int, int, int));
+static struct aclusergroup **FindGroupPtr __P((struct aclusergroup **, struct acluser *, int));
+static int AclSetPermCmd __P((struct acluser *, char *, struct comm *));
+static int AclSetPermWin __P((struct acluser *, struct acluser *, char *, struct win *));
+static int UserAcl __P((struct acluser *, struct acluser **, int, char **));
+static int UserAclCopy __P((struct acluser **, struct acluser **));
+
+
+static int
+GrowBitfield(bfp, len, delta, defaultbit)
+AclBits *bfp;
+int len, delta, defaultbit;
+{
+  AclBits n, o = *bfp;
+  int i;
+
+  if (!(n = (AclBits)calloc(1, (unsigned long)(&ACLBYTE((char *)0, len + delta + 1)))))
+    return -1;
+  for (i = 0; i < (len + delta); i++)
+    {
+      if (((i <  len) && (ACLBIT(i) & ACLBYTE(o, i))) ||
+          ((i >= len) && (defaultbit)))
+	ACLBYTE(n, i) |= ACLBIT(i);
+    }
+  if (len)
+    free((char *)o);
+  *bfp = n;
+  return 0;
+}
+
+#endif /* MULTIUSER */
+
+/* 
+ * Returns an nonzero Address. Its contents is either a User-ptr, 
+ * or NULL which may be replaced by a User-ptr to create the entry.
+ */
+struct acluser **
+FindUserPtr(name)
+char *name;
+{
+  struct acluser **u;
+
+  for (u = &users; *u; u = &(*u)->u_next)
+    if (!strcmp((*u)->u_name, name))
+      break;
+#ifdef MULTIUSER
+  debug3("FindUserPtr %s %sfound, id %d\n", name, (*u)?"":"not ", 
+         (*u)?(*u)->u_id:-1);
+#else /* MULTIUSER */
+  debug2("FindUserPtr %s %sfound\n", name, (*u)?"":"not ");
+#endif /* MULTIUSER */
+  return u;
+}
+
+int DefaultEsc = -1;		/* initialised by screen.c:main() */
+int DefaultMetaEsc = -1;
+
+/*
+ * Add a new user. His password may be NULL or "" if none. His name must not 
+ * be "none", as this represents the NULL-pointer when dealing with groups.
+ * He has default rights, determined by umask.
+ */
+int
+UserAdd(name, pass, up)
+char *name, *pass;
+struct acluser **up;
+{
+#ifdef MULTIUSER
+  int j;
+#endif
+
+  if (!up)
+    up = FindUserPtr(name);
+  if (*up)
+    {
+      if (pass)
+        (*up)->u_password = SaveStr(pass);
+      return 1;		/* he is already there */
+    }
+  if (strcmp("none", name))	/* "none" is a reserved word */
+    *up = (struct acluser *)calloc(1, sizeof(struct acluser));
+  if (!*up)
+    return -1;		/* he still does not exist */
+#ifdef COPY_PASTE
+  (*up)->u_plop.buf = NULL;
+  (*up)->u_plop.len = 0;
+# ifdef ENCODINGS
+  (*up)->u_plop.enc = 0;
+# endif
+#endif
+  (*up)->u_Esc = DefaultEsc;
+  (*up)->u_MetaEsc = DefaultMetaEsc;
+  strncpy((*up)->u_name, name, MAXLOGINLEN);
+  (*up)->u_password = NULL;
+  if (pass)
+    (*up)->u_password = SaveStr(pass);
+  if (!(*up)->u_password)
+    (*up)->u_password = NullStr;
+  (*up)->u_detachwin = -1;
+  (*up)->u_detachotherwin = -1;
+
+#ifdef MULTIUSER
+  (*up)->u_group = NULL;
+  /* now find an unused index */
+  for ((*up)->u_id = 0; (*up)->u_id < maxusercount; (*up)->u_id++)
+    if (!(ACLBIT((*up)->u_id) & ACLBYTE(userbits, (*up)->u_id)))
+      break;
+  debug2("UserAdd %s id %d\n", name, (*up)->u_id);
+  if ((*up)->u_id == maxusercount)
+    {
+      int j;
+      struct win *w;
+      struct acluser *u;
+
+      debug2("growing all bitfields %d += %d\n", maxusercount, USER_CHUNK);
+      /* the bitfields are full, grow a chunk */
+      /* first, the used_uid_indicator: */
+      if (GrowBitfield(&userbits, maxusercount, USER_CHUNK, 0))
+        {
+	  free((char *)*up); *up = NULL; return -1;
+	}
+      /* second, default command bits  */
+      /* (only if we generate commands dynamically) */
+/*
+      for (j = 0; j < ACL_BITS_PER_CMD; j++)
+	if (GrowBitfield(&default_c_userbits[j], maxusercount, USER_CHUNK, 
+	    default_c_bit[j]))
+	  {
+	    free((char *)*up); *up = NULL; return -1;
+	  }
+*/
+      /* third, the bits for each commands */
+      for (j = 0; j <= RC_LAST; j++)
+        {
+	  int i;
+	  
+	  for (i = 0; i < ACL_BITS_PER_CMD; i++)
+	    if (GrowBitfield(&comms[j].userbits[i], maxusercount, USER_CHUNK,
+	        default_c_bit[i]))
+	      {
+	        free((char *)*up); *up = NULL; return -1;
+	      }
+        }
+      /* fourth, default window creation bits per user */
+      for (u = users; u != *up; u = u->u_next)
+        {
+	  for (j = 0; j < ACL_BITS_PER_WIN; j++)
+	    {
+	      if (GrowBitfield(&u->u_umask_w_bits[j], maxusercount, USER_CHUNK,
+		  default_w_bit[j]))
+		{
+		  free((char *)*up); *up = NULL; return -1;
+		}
+	    }
+	}
+
+      /* fifth, the bits for each window */
+      /* keep these in sync with NewWindowAcl() */
+      for (w = windows; w; w = w->w_next)
+	{
+	  /* five a: the access control list */
+	  for (j = 0; j < ACL_BITS_PER_WIN; j++)
+	    if (GrowBitfield(&w->w_userbits[j], maxusercount, USER_CHUNK,
+		default_w_bit[j]))
+	      {
+		free((char *)*up); *up = NULL; return -1;
+	      }
+	  /* five b: the activity notify list */
+	  /* five c: the silence notify list */
+	  if (GrowBitfield(&w->w_mon_notify, maxusercount, USER_CHUNK, 0) ||
+	      GrowBitfield(&w->w_lio_notify, maxusercount, USER_CHUNK, 0))
+	    {  
+	      free((char *)*up); *up = NULL; return -1; 
+	    }
+	}
+      maxusercount += USER_CHUNK;
+    }
+
+  /* mark the user-entry as "in-use" */
+  ACLBYTE(userbits, (*up)->u_id) |= ACLBIT((*up)->u_id);    
+
+  /* user id 0 is the session creator, he has all rights */
+  if ((*up)->u_id == 0)
+    AclSetPerm(NULL, *up, "+a", "#?");
+  
+  /* user nobody has a fixed set of rights: */
+  if (!strcmp((*up)->u_name, "nobody"))
+    {
+      AclSetPerm(NULL, *up, "-rwx", "#?");
+      AclSetPerm(NULL, *up, "+x", "su");
+      AclSetPerm(NULL, *up, "+x", "detach");
+      AclSetPerm(NULL, *up, "+x", "displays");
+      AclSetPerm(NULL, *up, "+x", "version");
+    }
+
+  /* 
+   * Create his umask:
+   * Give default_w_bit's for all users, 
+   * but allow himself everything on "his" windows.
+   */
+  for (j = 0; j < ACL_BITS_PER_WIN; j++)
+    {
+      if (GrowBitfield(&(*up)->u_umask_w_bits[j], 0, maxusercount, 
+          default_w_bit[j]))
+        {
+          free((char *)*up); *up = NULL; return -1;
+        }
+      ACLBYTE((*up)->u_umask_w_bits[j], (*up)->u_id) |= ACLBIT((*up)->u_id);
+    }
+#else /* MULTIUSER */
+  debug1("UserAdd %s\n", name);
+#endif /* MULTIUSER */
+  return 0;
+}
+
+#if 0
+/* change user's password */
+int 
+UserSetPass(name, pass, up)
+char *name, *pass;
+struct acluser **up;
+{
+  if (!up)
+    up = FindUserPtr(name);
+  if (!*up)
+    return UserAdd(name, pass, up);
+  if (!strcmp(name, "nobody"))		/* he remains without password */
+    return -1;
+  strncpy((*up)->u_password, pass ? pass : "", 20);
+  (*up)->u_password[20] = '\0';
+  return 0;
+}
+#endif
+
+/* 
+ * Remove a user from the list. 
+ * Destroy all his permissions and completely detach him from the session.
+ */
+int 
+UserDel(name, up)
+char *name;
+struct acluser **up;
+{
+  struct acluser *u;
+#ifdef MULTIUSER
+  int i;
+#endif
+  struct display *old, *next;
+
+  if (!up)
+    up = FindUserPtr(name);
+  if (!(u = *up))
+    return -1;			/* he who does not exist cannot be removed */
+  old = display;
+  for (display = displays; display; display = next)
+    {
+      next = display->d_next;	/* read the next ptr now, Detach may zap it. */
+      if (D_user != u)
+	continue;
+      if (display == old)
+	old = NULL;
+      Detach(D_REMOTE);
+    }
+  display = old;
+  *up = u->u_next;
+
+#ifdef MULTIUSER
+  for (up = &users; *up; up = &(*up)->u_next)
+    {
+      /* unlink all group references to this user */
+      struct aclusergroup **g = &(*up)->u_group;
+
+      while (*g)
+        {
+	  if ((*g)->u == u)
+	    {
+	      struct aclusergroup *next = (*g)->next;
+
+	      free((char *)(*g));
+	      *g = next;
+	    }
+	  else
+	    g = &(*g)->next;
+	}
+    }
+  ACLBYTE(userbits, u->u_id) &= ~ACLBIT(u->u_id);
+  /* restore the bits in his slot to default: */
+  AclSetPerm(NULL, u, default_w_bit[ACL_READ] ? "+r" : "-r", "#");
+  AclSetPerm(NULL, u, default_w_bit[ACL_WRITE]? "+w" : "-w", "#");
+  AclSetPerm(NULL, u, default_w_bit[ACL_EXEC] ? "+x" : "-x", "#");
+  AclSetPerm(NULL, u, default_c_bit[ACL_EXEC] ? "+x" : "-x", "?");
+  for (i = 0; i < ACL_BITS_PER_WIN; i++)
+    free((char *)u->u_umask_w_bits[i]);
+#endif /* MULTIUSER */
+  debug1("FREEING user structure for %s\n", u->u_name);
+#ifdef COPY_PASTE
+  UserFreeCopyBuffer(u);
+#endif
+  free((char *)u);
+  if (!users)
+    {
+      debug("Last user deleted. Feierabend.\n");
+      Finit(0);	/* Destroying whole session. Noone could ever attach again. */
+    }
+  return 0;
+}
+
+
+#ifdef COPY_PASTE
+
+/*
+ * returns 0 if the copy buffer was really deleted.
+ * Also removes any references into the users copybuffer
+ */
+int
+UserFreeCopyBuffer(u)
+struct acluser *u;
+{
+  struct win *w;
+  struct paster *pa;
+
+  if (!u->u_plop.buf)
+    return 1;
+  for (w = windows; w; w = w->w_next)
+    {
+      pa = &w->w_paster;
+      if (pa->pa_pasteptr >= u->u_plop.buf &&
+          pa->pa_pasteptr - u->u_plop.buf < u->u_plop.len)
+        FreePaster(pa);
+    }
+  free((char *)u->u_plop.buf);
+  u->u_plop.len = 0;
+  u->u_plop.buf = 0;
+  return 0;
+}
+#endif	/* COPY_PASTE */
+
+#ifdef MULTIUSER
+/*
+ * Traverses group nodes. It searches for a node that references user u. 
+ * If recursive is true, nodes found in the users are also searched using 
+ * depth first method.  If none of the nodes references u, the address of 
+ * the last next pointer is returned. This address will contain NULL.
+ */ 
+static struct aclusergroup **
+FindGroupPtr(gp, u, recursive)
+struct aclusergroup **gp;
+struct acluser *u;
+int recursive;
+{
+  struct aclusergroup **g;
+  
+  ASSERT(recursive < 1000);		/* Ouch, cycle detection failed */
+  while (*gp)
+    {
+      if ((*gp)->u == u)
+        return gp;			/* found him here. */
+      if (recursive && 
+          *(g = FindGroupPtr(&(*gp)->u->u_group, u, recursive + 1)))
+	return g;			/* found him there. */
+      gp = &(*gp)->next;
+    }
+  return gp;				/* *gp is NULL */
+}
+
+static int
+PasswordMatches(pw, password)
+const char *pw, *password;
+{
+  if (!*password)
+    return 0;
+  char *buf = crypt((char *)pw, (char *)password);
+  return (buf && !strcmp(buf, password));
+}
+
+/* 
+ * Returns nonzero if failed or already linked.
+ * Both users are created on demand. 
+ * Cyclic links are prevented.
+ */
+int
+AclLinkUser(from, to)
+char *from, *to;
+{
+  struct acluser **u1, **u2;
+  struct aclusergroup **g;
+
+  if (!*(u1 = FindUserPtr(from)) && UserAdd(from, NULL, u1))
+    return -1;
+  if (!*(u2 = FindUserPtr(to)) && UserAdd(to, NULL, u2))
+    return -1;			/* hmm, could not find both users. */
+
+  if (*FindGroupPtr(&(*u2)->u_group, *u1, 1))
+    return 1;			/* cyclic link detected! */
+  if (*(g = FindGroupPtr(&(*u1)->u_group, *u2, 0)))
+    return 2;			/* aha, we are already linked! */
+
+  if (!(*g = (struct aclusergroup *)malloc(sizeof(struct aclusergroup))))
+    return -1;			/* Could not alloc link. Poor screen */
+  (*g)->u = (*u2);
+  (*g)->next = NULL;
+  return 0;
+}
+
+/*
+ * The user pointer stored at *up will be substituted by a pointer
+ * to the named user's structure, if passwords match.
+ * returns NULL if successfull, an static error string otherwise
+ */
+char *
+DoSu(up, name, pw1, pw2)
+struct acluser **up;
+char *name, *pw1, *pw2;
+{
+  struct acluser *u;
+  int sorry = 0;
+
+  if (!(u = *FindUserPtr(name)))
+    sorry++;
+  else
+    {
+#ifdef CHECKLOGIN
+      struct passwd *pp;
+#ifdef SHADOWPW
+      struct spwd *ss;
+      int t, c;
+#endif
+      char *pass = "";
+
+      if (!(pp = getpwnam(name)))
+        {
+	  debug1("getpwnam(\"%s\") failed\n", name);
+          if (!(pw1 && *pw1 && *pw1 != '\377'))
+	    {
+	      debug("no unix account, no screen passwd\n");
+	      sorry++;
+	    }
+	}
+      else
+        pass = pp->pw_passwd;
+#ifdef SHADOWPW
+      for (t = 0; t < 13; t++)
+        {
+	  c = pass[t];
+	  if (!(c == '.' || c == '/' ||
+	       (c >= '0' && c <= '9') ||
+	       (c >= 'a' && c <= 'z') ||
+	       (c >= 'A' && c <= 'Z')))
+	    break;
+	}
+      if (t < 13)
+        {
+	  if (!(ss = getspnam(name)))
+	    {
+	      debug1("getspnam(\"%s\") failed\n", name);
+	      sorry++;
+	    }
+	  else
+	    pass = ss->sp_pwdp;
+	}
+#endif /* SHADOWPW */
+
+      if (pw2 && *pw2 && *pw2 != '\377')	/* provided a system password */
+        {
+	  if (!PasswordMatches(pw2, pass))
+	    {
+	      debug("System password mismatch\n");
+	      sorry++;
+	    }
+	}
+      else					/* no pasword provided */
+        if (*pass)				/* but need one */
+	  sorry++;
+#endif /* CHECKLOGIN */
+      if (pw1 && *pw1 && *pw1 != '\377')	/* provided a screen password */
+	{
+	  if (!PasswordMatches(pw1, u->u_password))
+	    {
+	      debug("screen password mismatch\n");
+              sorry++;
+	    }
+	}
+      else					/* no pasword provided */
+        if (*u->u_password)			/* but need one */
+	  sorry++;
+    }
+  
+  debug2("syslog(LOG_NOTICE, \"screen %s: \"su %s\" ", SockPath, name);
+  debug2("%s for \"%s\"\n", sorry ? "failed" : "succeeded", (*up)->u_name);
+#ifndef NOSYSLOG
+# ifdef BSD_42
+  openlog("screen", LOG_PID);
+# else
+  openlog("screen", LOG_PID, LOG_AUTH);
+# endif /* BSD_42 */
+  syslog(LOG_NOTICE, "%s: \"su %s\" %s for \"%s\"", SockPath, name, 
+         sorry ? "failed" : "succeeded", (*up)->u_name);
+  closelog();
+#else
+  debug("NOT LOGGED.\n");
+#endif /* NOSYSLOG */
+
+  if (sorry)
+    return "Sorry."; 
+  else
+    *up = u;	/* substitute user now */
+  return NULL;
+}
+#endif /* MULTIUSER */
+
+/************************************************************************
+ *                     end of user managing code                        *
+ ************************************************************************/
+
+
+#ifdef MULTIUSER
+
+/* This gives the users default rights to the new window w created by u */
+int
+NewWindowAcl(w, u)
+struct win *w;
+struct acluser *u;
+{
+  int i, j;
+
+  debug2("NewWindowAcl %s's umask_w_bits for window %d\n", 
+         u ? u->u_name : "everybody", w->w_number);
+
+  /* keep these in sync with UserAdd part five. */
+  if (GrowBitfield(&w->w_mon_notify, 0, maxusercount, 0) ||
+      GrowBitfield(&w->w_lio_notify, 0, maxusercount, 0))
+    return -1;
+  for (j = 0; j < ACL_BITS_PER_WIN; j++)
+    {
+      /* we start with len 0 for the new bitfield size and add maxusercount */
+      if (GrowBitfield(&w->w_userbits[j], 0, maxusercount, 0))
+	{
+	  while (--j >= 0)
+	    free((char *)w->w_userbits[j]);
+	  free((char *)w->w_mon_notify);
+	  free((char *)w->w_lio_notify);
+	  return -1;
+	}
+      for (i = 0; i < maxusercount; i++)
+        if (u ? (ACLBIT(i) & ACLBYTE(u->u_umask_w_bits[j], i)) : 
+	        default_w_bit[j])
+	  ACLBYTE(w->w_userbits[j], i) |= ACLBIT(i);
+    }
+  return 0;
+}
+
+void
+FreeWindowAcl(w)
+struct win *w;
+{
+  int i;
+
+  for (i = 0; i < ACL_BITS_PER_WIN; i++)
+    free((char *)w->w_userbits[i]);
+  free((char *)w->w_mon_notify);
+  free((char *)w->w_lio_notify);
+}
+
+
+/* if mode starts with '-' we remove the users exec bit for cmd */
+/*
+ * NOTE: before you make this function look the same as 
+ * AclSetPermWin, try to merge both functions. 
+ */
+static int
+AclSetPermCmd(u, mode, cmd)
+struct acluser *u;
+char *mode;
+struct comm *cmd;
+{
+  int neg = 0;
+  char *m = mode;
+
+  while (*m)
+    {
+      switch (*m++)
+        {
+	case '-': 
+	  neg = 1;
+	  continue;
+        case '+':
+	  neg = 0;
+	  continue;
+        case 'a':
+        case 'e': 
+        case 'x': 
+/*	  debug3("AclSetPermCmd %s %s %s\n", u->u_name, mode, cmd->name); */
+	  if (neg)
+	    ACLBYTE(cmd->userbits[ACL_EXEC], u->u_id) &= ~ACLBIT(u->u_id);
+	  else
+	    ACLBYTE(cmd->userbits[ACL_EXEC], u->u_id) |= ACLBIT(u->u_id);
+	  break;
+        case 'r':
+	case 'w':
+	  break;
+        default:
+	  return -1;
+	}
+    }
+  return 0;
+}
+
+/* mode strings of the form +rwx -w+rx r -wx are parsed and evaluated */
+/*
+ * aclchg nerd -w+w 2
+ * releases a writelock on window 2 held by user nerd.
+ * Letter n allows network access on a window.
+ * uu should be NULL, except if you want to change his umask.
+ */
+static int
+AclSetPermWin(uu, u, mode, win)
+struct acluser *u, *uu;
+char *mode;
+struct win *win;
+{
+  int neg = 0;
+  int bit, bits;
+  AclBits *bitarray;
+  char *m = mode;
+
+  if (uu)
+    {
+      debug3("AclSetPermWin %s UMASK %s %s\n", uu->u_name, u->u_name, mode);
+      bitarray = uu->u_umask_w_bits;
+    }
+  else
+    {
+      ASSERT(win);
+      bitarray = win->w_userbits;
+      debug3("AclSetPermWin %s %s %d\n", u->u_name, mode, win->w_number);
+    }
+
+  while (*m)
+    {
+      switch (*m++)
+        {
+	case '-': 
+	  neg = 1;
+	  continue;
+        case '+':
+	  neg = 0;
+	  continue;
+        case 'r': 
+	  bits = (1 << ACL_READ);
+	  break;
+	case 'w':
+	  bits = (1 << ACL_WRITE);
+	  break;
+        case 'x':
+	  bits = (1 << ACL_EXEC);
+	  break;
+        case 'a':
+	  bits = (1 << ACL_BITS_PER_WIN) - 1;
+	  break;
+	default:
+	  return -1;
+        }
+      for (bit = 0; bit < ACL_BITS_PER_WIN; bit++)
+	{  
+	  if (!(bits & (1 << bit)))
+	    continue;
+	  if (neg)
+	    ACLBYTE(bitarray[bit], u->u_id) &= ~ACLBIT(u->u_id);
+	  else
+	    ACLBYTE(bitarray[bit], u->u_id) |= ACLBIT(u->u_id);
+	  if (!uu && (win->w_wlockuser == u) && neg && (bit == ACL_WRITE))
+	    {
+	      debug2("%s lost writelock on win %d\n", u->u_name, win->w_number);
+	      win->w_wlockuser = NULL;
+	      if (win->w_wlock == WLOCK_ON)
+		win->w_wlock = WLOCK_AUTO;
+	    }
+	}
+    }
+  if (uu && u->u_name[0] == '?' && u->u_name[1] == '\0')
+    {
+      /* 
+       * It is Mr. '?', the unknown user. He deserves special treatment as
+       * he defines the defaults. Sorry, this is global, not per user.
+       */
+      if (win)
+        {
+	  debug1("AclSetPermWin: default_w_bits '%s'.\n", mode);
+	  for (bit = 0; bit < ACL_BITS_PER_WIN; bit++)
+	    default_w_bit[bit] = 
+	      (ACLBYTE(bitarray[bit], u->u_id) & ACLBIT(u->u_id)) ? 1 : 0;
+	}
+      else
+	{
+	  /*
+	   * Hack. I do not want to duplicate all the above code for
+	   * AclSetPermCmd. This asumes that there are not more bits 
+	   * per cmd than per win.
+	   */
+	  debug1("AclSetPermWin: default_c_bits '%s'.\n", mode);
+	  for (bit = 0; bit < ACL_BITS_PER_CMD; bit++)
+	    default_c_bit[bit] = 
+	      (ACLBYTE(bitarray[bit], u->u_id) & ACLBIT(u->u_id)) ? 1 : 0;
+	}
+      UserDel(u->u_name, NULL);
+    }
+  return 0;
+}
+
+/* 
+ * String is broken down into comand and window names, mode applies
+ * A command name matches first, so do not use these as window names.
+ * uu should be NULL, except if you want to change his umask.
+ */
+int
+AclSetPerm(uu, u, mode, s)
+struct acluser *uu, *u;
+char *mode, *s;
+{
+  struct win *w;
+  int i;
+  char *p, ch;
+
+  debug3("AclSetPerm(uu, user '%s', mode '%s', object '%s')\n",
+         u->u_name, mode, s);
+  while (*s)
+    {
+      switch (*s)
+	{
+	case '*':			/* all windows and all commands */
+	  return AclSetPerm(uu, u, mode, "#?");
+	case '#':
+	  if (uu)			/* window umask or .. */
+	    AclSetPermWin(uu, u, mode, (struct win *)1);
+	  else				/* .. or all windows */
+	    for (w = windows; w; w = w->w_next)
+	      AclSetPermWin((struct acluser *)0, u, mode, w);
+	  s++;
+	  break;
+	case '?':
+	  if (uu)			/* command umask or .. */
+	    AclSetPermWin(uu, u, mode, (struct win *)0);
+	  else				/* .. or all commands */
+	    for (i = 0; i <= RC_LAST; i++)
+	      AclSetPermCmd(u, mode, &comms[i]);
+	  s++;
+	  break;
+	default:
+	  for (p = s; *p && *p != ' ' && *p != '\t' && *p != ','; p++)
+	    ;
+	  if ((ch = *p))
+	    *p++ = '\0';
+	  if ((i = FindCommnr(s)) != RC_ILLEGAL)
+	    AclSetPermCmd(u, mode, &comms[i]);
+	  else if (((i = WindowByNoN(s)) >= 0) && wtab[i])
+	    AclSetPermWin((struct acluser *)0, u, mode, wtab[i]);
+	  else
+	    /* checking group name */
+	    return -1;
+	  if (ch)
+	    p[-1] = ch;
+	  s = p; 
+	}    
+    }
+  return 0;
+}
+
+/* 
+ * Generic ACL Manager:
+ *
+ * This handles acladd and aclchg identical.
+ * With 2 or 4 parameters, the second parameter is a password.
+ * With 3 or 4 parameters the last two parameters specify the permissions
+ *   else user is added with full permissions.
+ * With 1 parameter the users permissions are copied from user *argv.
+ *   Unlike the other cases, u->u_name should not match *argv here.
+ * uu should be NULL, except if you want to change his umask.
+ */
+static int
+UserAcl(uu, u, argc, argv)
+struct acluser *uu, **u;
+int argc;
+char **argv;
+{
+  if ((*u && !strcmp((*u)->u_name, "nobody")) ||
+      (argc > 1 && !strcmp(argv[0], "nobody")))
+    return -1;			/* do not change nobody! */
+
+  switch (argc)
+    {
+    case 1+1+2:
+      debug2("UserAcl: user '%s', password '%s':", argv[0], argv[1]);
+      return (UserAdd(argv[0], argv[1], u) < 0) || 
+	      AclSetPerm(uu, *u, argv[2], argv[3]);
+    case 1+2:
+      debug1("UserAcl: user '%s', no password:", argv[0]);
+      return (UserAdd(argv[0],    NULL, u) < 0) || 
+	      AclSetPerm(uu, *u, argv[1], argv[2]);
+    case 1+1:
+      debug2("UserAcl: user '%s', password '%s'\n", argv[0], argv[1]);
+      return UserAdd(argv[0], argv[1], u) < 0;
+    case 1:
+      debug1("UserAcl: user '%s', no password:", argv[0]);
+      return (UserAdd(argv[0],    NULL, u) < 0) || 
+	      AclSetPerm(uu, *u, "+a", "#?");
+    default:
+      return -1;
+    }
+}
+
+static int
+UserAclCopy(to_up, from_up)
+struct acluser **to_up, **from_up;
+{
+  struct win *w;
+  int i, j, to_id, from_id;
+
+  if (!*to_up || !*from_up)
+    return -1;
+  debug2("UserAclCopy: from user '%s' to user '%s'\n", 
+         (*from_up)->u_name, (*to_up)->u_name);
+  if ((to_id = (*to_up)->u_id) == (from_id = (*from_up)->u_id))
+    return -1;
+  for (w = windows; w; w = w->w_next)
+    {
+      for (i = 0; i < ACL_BITS_PER_WIN; i++)
+        {
+	  if (ACLBYTE(w->w_userbits[i], from_id) & ACLBIT(from_id))
+	    ACLBYTE(w->w_userbits[i], to_id) |= ACLBIT(to_id);
+	  else
+	    {
+	      ACLBYTE(w->w_userbits[i], to_id) &= ~ACLBIT(to_id);
+	      if ((w->w_wlockuser == *to_up) && (i == ACL_WRITE))
+		{
+		  debug2("%s lost wlock on win %d\n", 
+		         (*to_up)->u_name, w->w_number);
+		  w->w_wlockuser = NULL;
+		  if (w->w_wlock == WLOCK_ON)
+		    w->w_wlock = WLOCK_AUTO;
+		}
+	    }
+	}
+    }
+  for (j = 0; j <= RC_LAST; j++)
+    {
+      for (i = 0; i < ACL_BITS_PER_CMD; i++)
+        {
+	  if (ACLBYTE(comms[j].userbits[i], from_id) & ACLBIT(from_id))
+	    ACLBYTE(comms[j].userbits[i], to_id) |= ACLBIT(to_id);
+	  else
+	    ACLBYTE(comms[j].userbits[i], to_id) &= ~ACLBIT(to_id);
+	}
+    }
+
+  return 0;
+}
+
+/*
+ * Syntax:
+ * 	user [password] [+rwx #?]
+ * 	* [password] [+rwx #?]
+ *      user1,user2,user3 [password] [+rwx #?]
+ *	user1,user2,user3=user
+ * uu should be NULL, except if you want to change his umask.
+ */
+int
+UsersAcl(uu, argc, argv)
+struct acluser *uu;
+int argc;
+char **argv;
+{
+  char *s;
+  int r;
+  struct acluser **cf_u = NULL;
+
+  if (argc == 1)
+    {
+      char *p = NULL;
+
+      s = argv[0]; 
+      while (*s)
+        if (*s++ == '=') p = s;
+      if (p)
+        {
+          p[-1] = '\0';
+          cf_u = FindUserPtr(p);
+        }
+    }
+
+  if (argv[0][0] == '*' && argv[0][1] == '\0')
+    {
+      struct acluser **u;
+  
+      debug("all users acls.\n");
+      for (u = &users; *u; u = &(*u)->u_next)
+	if (strcmp("nobody", (*u)->u_name) && 
+	    ((cf_u) ?
+	     ((r = UserAclCopy(u, cf_u)) < 0) :
+	     ((r = UserAcl(uu, u, argc, argv)) < 0)))
+	  return -1;
+      return 0;
+    } 
+
+  do
+    {
+      for (s = argv[0]; *s && *s!=' ' && *s!='\t' && *s!=',' && *s!='='; s++)
+	;
+      *s ? (*s++ = '\0') : (*s = '\0');
+      debug2("UsersAcl(uu, \"%s\", argc=%d)\n", argv[0], argc);
+      if ((cf_u) ?
+	  ((r = UserAclCopy(FindUserPtr(argv[0]), cf_u)) < 0) :
+	  ((r = UserAcl(uu, FindUserPtr(argv[0]), argc, argv)) < 0))
+        return -1;
+    } while (*(argv[0] = s));
+  return 0;
+}
+
+/*
+ * Preprocess argments, so that umask can be set with UsersAcl
+ * 
+ * all current users		umask ±rwxn
+ * one specific user		umask user1±rwxn
+ * several users		umask user1,user2,...±rwxn
+ * default_w_bits		umask ?±rwxn
+ * default_c_bits		umask ??±rwxn
+ */
+int 
+AclUmask(u, str, errp)
+struct acluser *u;
+char *str;
+char **errp;
+{
+  char mode[16]; 
+  char *av[3];
+  char *p, c = '\0';
+
+  /* split str into user and bits section. */
+  for (p = str; *p; p++)
+    if ((c = *p) == '+' || c == '-')
+      break;
+  if (!*p)
+    {
+      *errp = "Bad argument. Should be ``[user[,user...]{+|-}rwxn''.";
+      return -1;
+    }
+  strncpy(mode, p, 15);
+  mode[15] = '\0';
+  *p = '\0';
+
+  /* construct argument vector */
+  if (!strcmp("??", str))
+    {
+      str++;
+      av[2] = "?";
+    }
+  else
+    av[2] = "#";
+  av[1] = mode;
+  av[0] = *str ? str : "*";
+  /* call UsersAcl */
+  if (UsersAcl(u, 3, av))
+    {
+      *errp = "UsersAcl failed. Hmmm.";
+      *p = c;
+      return -1;
+    }
+  *p = c;
+  return 0;
+}
+
+void
+AclWinSwap(a, b)
+int a, b;
+{
+  debug2("AclWinSwap(%d, %d) NOP.\n", a, b);
+}
+
+struct acluser *EffectiveAclUser = NULL;	/* hook for AT command permission */
+
+int 
+AclCheckPermWin(u, mode, w)
+struct acluser *u;
+int mode;
+struct win *w;
+{
+  int ok;
+
+  if (mode < 0 || mode >= ACL_BITS_PER_WIN)
+    return -1;
+  if (EffectiveAclUser)
+    {
+      debug1("AclCheckPermWin: WARNING user %s overridden!\n", u->u_name);
+      u = EffectiveAclUser;
+    }
+  ok = ACLBYTE(w->w_userbits[mode], u->u_id) & ACLBIT(u->u_id);
+  debug3("AclCheckPermWin(%s, %d, %d) = ", u->u_name, mode, w->w_number);
+
+  if (!ok)
+    {
+      struct aclusergroup **g = &u->u_group;
+      struct acluser *saved_eff = EffectiveAclUser;
+
+      EffectiveAclUser = NULL;
+      while (*g)
+        {
+	  if (!AclCheckPermWin((*g)->u, mode, w))
+	    break;
+	  g = &(*g)->next;
+	}
+      EffectiveAclUser = saved_eff;
+      if (*g)
+        ok = 1;
+    }
+  debug1("%d\n", !ok);
+  return !ok;
+}
+
+int 
+AclCheckPermCmd(u, mode, c)
+struct acluser *u;
+int mode;
+struct comm *c;
+{
+  int ok;
+
+  if (mode < 0 || mode >= ACL_BITS_PER_CMD)
+    return -1;
+  if (EffectiveAclUser)
+    {
+      debug1("AclCheckPermCmd: WARNING user %s overridden!\n", u->u_name);
+      u = EffectiveAclUser;
+    }
+  ok = ACLBYTE(c->userbits[mode], u->u_id) & ACLBIT(u->u_id);
+  debug3("AclCheckPermCmd(%s %d %s) = ", u->u_name, mode, c->name); 
+  if (!ok)
+    {
+      struct aclusergroup **g = &u->u_group;
+      struct acluser *saved_eff = EffectiveAclUser;
+
+      EffectiveAclUser = NULL;
+      while (*g)
+        {
+          if (!AclCheckPermCmd((*g)->u, mode, c))
+            break;   
+          g = &(*g)->next;
+        }                          
+      EffectiveAclUser = saved_eff;
+      if (*g)
+        ok = 1;  
+    }
+  debug1("%d\n", !ok);
+  return !ok;
+}
+
+#endif /* MULTIUSER */