patch for sysv-style group behaviour

[Marcus Brinkmann]

Hi,

here is a patch for sysv style group behaviour.  New nodes are created
with a gid:

* If the parent dir is sgid:
  + The node inherits the group of the parent dir.
  + If the node is a dir, it inherits the sgid bit.
  + If the node is not a dir, and user is not in the group,
    deny a requested sgid bit (this is the old default).
* If the parent dir is not sgid:
  + If the user has gids, the node is created with the first gid.
  + If the user has no gids, the node inherits the gid of the parent
    dir, and a requested sgid bit is denied.  This is the old behaviour.
    
I hope this is correct, I did not verify it against the Linux kernel
behaviour yet.  And I think that for the no-user, the old default was
good enough.  I gave it some basic testing.  The option is named
--sysv-groups.  It can be switched off with --bsd-groups (as
--no-sysv-groups is quite lame).  Or maybe we should have
--group-style=bsd|sysv?

Please let me know what you think,
Marcus


Index: ChangeLog
===================================================================
RCS file: /cvsroot/hurd/hurd/libdiskfs/ChangeLog,v
retrieving revision 1.171
diff -u -p -r1.171 ChangeLog
--- ChangeLog   26 Mar 2002 19:06:57 -0000      1.171
+++ ChangeLog   30 Apr 2002 00:26:24 -0000
@@ -1,3 +1,20 @@
+2002-04-30  Marcus Brinkmann  <marcus@gnu.org>
+
+       * priv.h: Add OPT_SYSV_GROUPS and OPT_BSD_GROUPS.
+       (_diskfs_sysv_groups): New declaration.
+       * node-create.c (_diskfs_sysv_groups): New variable.
+       (diskfs_create_node): Implement SysV group behaviour.
+       * opts-common.c (diskfs_common_options): Add --sysv-groups and
+       --bsd-groups.
+       * opts-append-std.c (diskfs_append_std_options): Add --sysv-groups
+       if set.
+       * opts-std-startup.c (parse_startup_opt): Add toggle for
+       _diskfs_sysv_groups.
+       * opts-std-runtime.c (struct parse_hook): Add sysvgroups.
+       (set_opts): Handle H->sysvgroups.
+       (parse_opt): Initialize H->sysvgroups.  Handle OPT_SYSV_GROUPS and
+       OPT_BSD_GROUPS.
+
 2002-03-23  James A. Morrison  <ja2morri@uwaterloo.ca>
 
        * init-startup.c (_diskfs_init_completed): Use error, not
Index: node-create.c
===================================================================
RCS file: /cvsroot/hurd/hurd/libdiskfs/node-create.c,v
retrieving revision 1.16
diff -u -p -r1.16 node-create.c
--- node-create.c       15 Apr 2001 22:44:03 -0000      1.16
+++ node-create.c       30 Apr 2002 00:26:24 -0000
@@ -17,6 +17,11 @@
 
 #include "priv.h"
 
+/* This enables SysV style group behaviour.  New nodes inherit the GID
+   of the user creating them unless the SGID bit is set of the parent
+   directory.  */
+int _diskfs_sysv_groups;
+
 /* Create a new node. Give it MODE; if that includes IFDIR, also
    initialize `.' and `..' in the new directory.  Return the node in NPP.
    CRED identifies the user responsible for the call.  If NAME is nonzero,
@@ -70,9 +75,40 @@ diskfs_create_node (struct node *dir,
   if (np->author_tracks_uid)
     np->dn_stat.st_author = newuid;
 
-  newgid = dir->dn_stat.st_gid;
-  if (!idvec_contains (cred->user->gids, newgid))
-    mode &= ~S_ISGID;
+  if (!_diskfs_sysv_groups)
+    {
+      newgid = dir->dn_stat.st_gid;
+      if (!idvec_contains (cred->user->gids, newgid))
+       mode &= ~S_ISGID;
+    }
+  else
+    {
+      if (dir->dn_stat.st_mode & S_ISGID)
+       {
+         /* If the parent dir has the sgid bit set, inherit its gid.
+            If the new node is a directory, also inherit the sgid bit
+            set.  */
+         newgid = dir->dn_stat.st_gid;
+         if (S_ISDIR (mode))
+           mode |= S_ISGID;
+         else
+           {
+             if (!idvec_contains (cred->user->gids, newgid))
+               mode &= ~S_ISGID;
+           }
+       }
+      else
+       {
+         if (cred->user->gids->num)
+           newgid = cred->user->gids->ids[0];
+         else
+           {
+             newgid = dir->dn_stat.st_gid;
+             mode &= ~S_ISGID;
+           }
+       }
+    }
+
   err = diskfs_validate_group_change (np, newgid);
   if (err)
     goto change_err;
Index: opts-append-std.c
===================================================================
RCS file: /cvsroot/hurd/hurd/libdiskfs/opts-append-std.c,v
retrieving revision 1.8
diff -u -p -r1.8 opts-append-std.c
--- opts-append-std.c   12 Mar 2002 01:50:49 -0000      1.8
+++ opts-append-std.c   30 Apr 2002 00:26:25 -0000
@@ -42,6 +42,8 @@ diskfs_append_std_options (char **argz, 
     err = argz_add (argz, argz_len, "--no-exec");
   if (!err && _diskfs_noatime)
     err = argz_add (argz, argz_len, "--no-atime");
+  if (!err && _diskfs_sysv_groups)
+    err = argz_add (argz, argz_len, "--sysv-groups");
 
   if (! err)
     {
Index: opts-common.c
===================================================================
RCS file: /cvsroot/hurd/hurd/libdiskfs/opts-common.c,v
retrieving revision 1.5
diff -u -p -r1.5 opts-common.c
--- opts-common.c       14 May 2000 20:35:53 -0000      1.5
+++ opts-common.c       30 Apr 2002 00:26:25 -0000
@@ -47,5 +47,8 @@ const struct argp_option diskfs_common_o
    "Do not update file access times on disk for reads"},
   {"noatime",  0,   0, OPTION_ALIAS | OPTION_HIDDEN},
   {"atime", OPT_ATIME, 0, 0, "Do update file access times for reads normally"},
+  {"sysv-groups", OPT_SYSV_GROUPS, 0, 0, "Create new nodes with gid of user"},
+  {"bsd-groups", OPT_BSD_GROUPS, 0, 0,
+   "Create new nodes with gid of parent dir (default)"},
   {0, 0}
 };
Index: opts-std-runtime.c
===================================================================
RCS file: /cvsroot/hurd/hurd/libdiskfs/opts-std-runtime.c,v
retrieving revision 1.10
diff -u -p -r1.10 opts-std-runtime.c
--- opts-std-runtime.c  12 Oct 1999 07:11:11 -0000      1.10
+++ opts-std-runtime.c  30 Apr 2002 00:26:25 -0000
@@ -32,7 +32,8 @@ std_runtime_options[] =
 
 struct parse_hook
 {
-  int readonly, sync, sync_interval, remount, nosuid, noexec, noatime;
+  int readonly, sync, sync_interval, remount, nosuid, noexec, noatime,
+    sysvgroups;
 };
 
 /* Implement the options in H, and free H.  */
@@ -79,6 +80,8 @@ set_opts (struct parse_hook *h)
     _diskfs_noexec = h->noexec;
   if (h->noatime != -1)
     _diskfs_noatime = h->noatime;
+  if (h->sysvgroups != -1)
+    _diskfs_sysv_groups = h->sysvgroups;
 
   free (h);
 
@@ -101,6 +104,8 @@ parse_opt (int opt, char *arg, struct ar
     case OPT_SUID_OK: h->nosuid = 0; break;
     case OPT_EXEC_OK: h->noexec = 0; break;
     case OPT_ATIME: h->noatime = 0; break;
+    case OPT_SYSV_GROUPS: h->sysvgroups = 1; break;
+    case OPT_BSD_GROUPS: h->sysvgroups = 0; break;
     case 'n': h->sync_interval = 0; h->sync = 0; break;
     case 's':
       if (arg)
@@ -124,7 +129,7 @@ parse_opt (int opt, char *arg, struct ar
          h->sync = diskfs_synchronous;
          h->sync_interval = -1;
          h->remount = 0;
-         h->nosuid = h->noexec = h->noatime = -1;
+         h->nosuid = h->noexec = h->noatime = h->sysvgroups = -1;
 
          /* We know that we have one child, with which we share our hook.  */
          state->child_inputs[0] = h;
Index: opts-std-startup.c
===================================================================
RCS file: /cvsroot/hurd/hurd/libdiskfs/opts-std-startup.c,v
retrieving revision 1.19
diff -u -p -r1.19 opts-std-startup.c
--- opts-std-startup.c  24 Aug 2001 02:23:57 -0000      1.19
+++ opts-std-startup.c  30 Apr 2002 00:26:26 -0000
@@ -82,6 +82,7 @@ parse_startup_opt (int opt, char *arg, s
       TOGGLE (_diskfs_nosuid, 'S', OPT_SUID_OK);
       TOGGLE (_diskfs_noexec, 'E', OPT_EXEC_OK);
       TOGGLE (_diskfs_noatime, 'A', OPT_ATIME);
+      TOGGLE (_diskfs_sysv_groups, OPT_SYSV_GROUPS, OPT_BSD_GROUPS);
 #undef TOGGLE
 
     case 's':
Index: priv.h
===================================================================
RCS file: /cvsroot/hurd/hurd/libdiskfs/priv.h,v
retrieving revision 1.44
diff -u -p -r1.44 priv.h
--- priv.h      6 May 2001 00:49:27 -0000       1.44
+++ priv.h      30 Apr 2002 00:26:26 -0000
@@ -35,6 +35,11 @@ extern int _diskfs_nosuid, _diskfs_noexe
 /* This relaxes the requirement to set `st_atime'.  */
 extern int _diskfs_noatime;
 
+/* This enables SysV style group behaviour.  New nodes inherit the GID
+   of the user creating them unless the SGID bit is set of the parent
+   directory.  */
+extern int _diskfs_sysv_groups;
+
 /* This is the -C argument value.  */
 extern char *_diskfs_chroot_directory;
 
@@ -51,6 +56,8 @@ extern const struct argp_option diskfs_c
 #define OPT_SUID_OK    600     /* --suid-ok */
 #define OPT_EXEC_OK    601     /* --exec-ok */
 #define OPT_ATIME      602     /* --atime */
+#define OPT_SYSV_GROUPS        603     /* --sysv-groups */
+#define OPT_BSD_GROUPS 604     /* --bsd-groups */
 
 /* Common value for diskfs_common_options and diskfs_default_sync_interval. */
 #define DEFAULT_SYNC_INTERVAL 5