Re: [Bug-tar] Failure with --owner and --group when names cannot be mapped to IDs

[Paul Eggert]

On 08/08/2011 03:28 AM, Thayne Harbaugh wrote:

> Attached is a patch that allows archives to be created with
> arbitrary owner or group names.

Thanks for the bug report and patch; I was unaware of the problem.
This runs into another area that I'd been meaning to enhance for some
time: tar doesn't let you specify both user name and number (only one
or the other), and similarly for groups.  I wrote and installed the
following patch into GNU tar, to address both enhancement requests
simultaneously.  Please give it a try when you have the time.

tar: --owner and --group names and numbers
The --owner and --group options now accept operands of the form
NAME:NUM, so that you can specify both symbolic name and numeric
ID for owner and group.  Also, in these options, NAME no longer
needs to be present in the current host's user and group
databases; this implements Debian enhancement request 136231
<http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=136231> reported
by Mark W. Eichin, communicated by Thayne Harbaugh to bug-tar in
<http://lists.gnu.org/archive/html/bug-tar/2011-08/msg00001.html>.
* NEWS, doc/tar.texi (Option Summary, override): Document enhancement.
* src/common.h (group_name_option, owner_name_option): New decls.
* src/create.c (start_header): Don't assume owner and group names
are in current host database.
* src/tar.c (parse_owner_group): New function, for parsing NAME:NUM.
(parse_opt): Use it.
(decode_options): Initialize owner_name_option, group_name_option.
* tests/owner.at: New file, to test this enhancement.
* tests/Makefile.am (TESTSUITE_AT): Add it.
* tests/testsuite.at: Include it.
diff --git a/NEWS b/NEWS
index 12c1dd6..06955f4 100644
--- a/NEWS
+++ b/NEWS
@@ -1,7 +1,18 @@
-GNU tar NEWS - User visible changes. 2011-03-12
+GNU tar NEWS - User visible changes. 2011-08-13
 Please send GNU tar bug reports to <address@hidden>

 
+version ?.? - ?, 201?-??-??
+
+* New features
+
+** --owner and --group names and numbers
+
+The --owner and --group options now accept operands of the form
+NAME:NUM, so that you can specify both symbolic name and numeric ID
+for owner and group.  In these options, NAME no longer needs to be
+present in the current host's user and group databases.
+
 version 1.26 - Sergey Poznyakoff, 2011-03-12

 * Bugfixes
diff --git a/doc/tar.texi b/doc/tar.texi
index 357c8c1..48e8c3c 100644
--- a/doc/tar.texi
+++ b/doc/tar.texi
@@ -2713,9 +2713,9 @@ tutorial}).
 @item address@hidden

 Files added to the @command{tar} archive will have a group @acronym{ID} of 
@var{group},
-rather than the group from the source file.  @var{group} is first decoded
-as a group symbolic name, but if this interpretation fails, it has to be
-a decimal numeric group @acronym{ID}.  @xref{override}.
+rather than the group from the source file.  @var{group} can specify a
+symbolic name, or a numeric @acronym{ID}, or both as
address@hidden:@var{id}.  @xref{override}.

 Also see the comments for the @address@hidden option.

@@ -3082,8 +3082,8 @@ from an archive.  @xref{Overwrite Old Files}.

 Specifies that @command{tar} should use @var{user} as the owner of members
 when creating archives, instead of the user associated with the source
-file.  @var{user} is first decoded as a user symbolic name, but if
-this interpretation fails, it has to be a decimal numeric user @acronym{ID}.
+file.  @var{user} can specify a symbolic name, or a numeric
address@hidden, or both as @var{name}:@var{id}.
 @xref{override}.

 This option does not affect extraction from archives.
@@ -4947,8 +4947,22 @@ tar: Option --mtime: Treating date `yesterday' as 
2006-06-20

 Specifies that @command{tar} should use @var{user} as the owner of members
 when creating archives, instead of the user associated with the source
-file.  The argument @var{user} can be either an existing user symbolic
-name, or a decimal numeric user @acronym{ID}.
+file.
+
+If @var{user} contains a colon, it is taken to be of the form
address@hidden:@var{id} where a nonempty @var{name} specifies the user
+name and a nonempty @var{id} specifies the decimal numeric user
address@hidden  If @var{user} does not contain a colon, it is taken to
+be a user number if it is one or more decimal digits; otherwise it is
+taken to be a user name.
+
+If a name is given but no number, the number is inferred from the
+current host's user database if possible, and the file's user number
+is used otherwise.  If a number is given but no name, the name is
+inferred from the number if possible, and an empty name is used
+otherwise.  If both name and number are given, the user database is
+not consulted, and the name and number need not be valid on the
+current host.

 There is no value indicating a missing number, and @samp{0} usually means
 @code{root}.  Some people like to force @samp{0} as the value to offer in
@@ -4971,8 +4985,9 @@ $ @kbd{tar -c -f archive.tar --owner=root .}
 @opindex group

 Files added to the @command{tar} archive will have a group @acronym{ID} of 
@var{group},
-rather than the group from the source file.  The argument @var{group}
-can be either an existing group symbolic name, or a decimal numeric group 
@acronym{ID}.
+rather than the group from the source file.  As with @option{--owner},
+the argument @var{group} can be an existing group symbolic name, or a
+decimal numeric group @acronym{ID}, or @var{name}:@var{id}.
 @end table

 @node Ignore Failed Read
diff --git a/src/common.h b/src/common.h
index 0b9bd7a..8c81cad 100644
--- a/src/common.h
+++ b/src/common.h
@@ -158,7 +158,8 @@ enum exclusion_tag_type
   };

 /* Specified value to be put into tar file in place of stat () results, or
-   just -1 if such an override should not take place.  */
+   just null and -1 if such an override should not take place.  */
+GLOBAL char const *group_name_option;
 GLOBAL gid_t group_option;

 GLOBAL bool ignore_failed_read_option;
@@ -230,7 +231,8 @@ GLOBAL bool numeric_owner_option;
 GLOBAL bool one_file_system_option;

 /* Specified value to be put into tar file in place of stat () results, or
-   just -1 if such an override should not take place.  */
+   just null and -1 if such an override should not take place.  */
+GLOBAL char const *owner_name_option;
 GLOBAL uid_t owner_option;

 GLOBAL bool recursive_unlink_option;
diff --git a/src/create.c b/src/create.c
index 43b5a4c..9839e1f 100644
--- a/src/create.c
+++ b/src/create.c
@@ -920,8 +920,15 @@ start_header (struct tar_stat_info *st)
     }
   else
     {
-      uid_to_uname (st->stat.st_uid, &st->uname);
-      gid_to_gname (st->stat.st_gid, &st->gname);
+      if (owner_name_option)
+       st->uname = xstrdup (owner_name_option);
+      else
+       uid_to_uname (st->stat.st_uid, &st->uname);
+
+      if (group_name_option)
+       st->gname = xstrdup (group_name_option);
+      else
+       gid_to_gname (st->stat.st_gid, &st->gname);

       if (archive_format == POSIX_FORMAT
          && (strlen (st->uname) > UNAME_FIELD_SIZE
diff --git a/src/tar.c b/src/tar.c
index 9578162..6d37044 100644
--- a/src/tar.c
+++ b/src/tar.c
@@ -1364,6 +1364,58 @@ expand_pax_option (struct tar_args *targs, const char 
*arg)
 }

 
+static uintmax_t
+parse_owner_group (char *arg, uintmax_t field_max, char const **name_option)
+{
+  strtol_error err;
+  uintmax_t u = UINTMAX_MAX;
+  char *end;
+  char const *name = 0;
+  char const *invalid_num = 0;
+  char *colon = strchr (arg, ':');
+
+  if (colon)
+    {
+      char const *num = colon + 1;
+      *colon = '\0';
+      if (*arg)
+       name = arg;
+      if (num && (! (xstrtoumax (num, &end, 10, &u, "") == LONGINT_OK
+                    && u <= field_max)))
+       invalid_num = num;
+    }
+  else
+    {
+      uintmax_t u1;
+      switch ('0' <= *arg && *arg <= '9'
+             ? xstrtoumax (arg, &end, 10, &u1, "")
+             : LONGINT_INVALID)
+       {
+       default:
+         name = arg;
+         break;
+
+       case LONGINT_OK:
+         if (u1 <= field_max)
+           {
+             u = u1;
+             break;
+           }
+         /* Fall through.  */
+       case LONGINT_OVERFLOW:
+         invalid_num = arg;
+         break;
+       }
+    }
+
+  if (invalid_num)
+    FATAL_ERROR ((0, 0, "%s: %s", quotearg_colon (invalid_num),
+                 _("Invalid owner or group ID")));
+  if (name)
+    *name_option = name;
+  return u;
+}
+
 #define TAR_SIZE_SUFFIXES "bBcGgkKMmPTtw"

 static error_t
@@ -1836,17 +1888,18 @@ parse_opt (int key, char *arg, struct argp_state *state)
       break;

     case GROUP_OPTION:
-      if (! (strlen (arg) < GNAME_FIELD_SIZE
-            && gname_to_gid (arg, &group_option)))
-       {
-         uintmax_t g;
-         if (xstrtoumax (arg, 0, 10, &g, "") == LONGINT_OK
-             && g == (gid_t) g)
-           group_option = g;
-         else
-           FATAL_ERROR ((0, 0, "%s: %s", quotearg_colon (arg),
-                         _("Invalid group")));
-       }
+      {
+       uintmax_t u = parse_owner_group (arg, TYPE_MAXIMUM (gid_t),
+                                        &group_name_option);
+       if (u == UINTMAX_MAX)
+         {
+           group_option = -1;
+           if (group_name_option)
+             gname_to_gid (group_name_option, &group_option);
+         }
+       else
+         group_option = u;
+      }
       break;

     case MODE_OPTION:
@@ -1922,17 +1975,18 @@ parse_opt (int key, char *arg, struct argp_state *state)
       break;

     case OWNER_OPTION:
-      if (! (strlen (arg) < UNAME_FIELD_SIZE
-            && uname_to_uid (arg, &owner_option)))
-       {
-         uintmax_t u;
-         if (xstrtoumax (arg, 0, 10, &u, "") == LONGINT_OK
-             && u == (uid_t) u)
-           owner_option = u;
-         else
-           FATAL_ERROR ((0, 0, "%s: %s", quotearg_colon (arg),
-                         _("Invalid owner")));
-       }
+      {
+       uintmax_t u = parse_owner_group (arg, TYPE_MAXIMUM (uid_t),
+                                        &owner_name_option);
+       if (u == UINTMAX_MAX)
+         {
+           owner_option = -1;
+           if (owner_name_option)
+             uname_to_uid (owner_name_option, &owner_option);
+         }
+       else
+         owner_option = u;
+      }
       break;

     case QUOTE_CHARS_OPTION:
@@ -2241,8 +2295,8 @@ decode_options (int argc, char **argv)
   tar_sparse_major = 1;
   tar_sparse_minor = 0;

-  owner_option = -1;
-  group_option = -1;
+  owner_option = -1; owner_name_option = NULL;
+  group_option = -1; group_name_option = NULL;

   check_device_option = true;

diff --git a/tests/Makefile.am b/tests/Makefile.am
index d9c9aae..7acc9d6 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -128,6 +128,7 @@ TESTSUITE_AT = \
  old.at\
  options.at\
  options02.at\
+ owner.at\
  pipe.at\
  recurse.at\
  rename01.at\
diff --git a/tests/owner.at b/tests/owner.at
new file mode 100644
index 0000000..799bd43
--- /dev/null
+++ b/tests/owner.at
@@ -0,0 +1,45 @@
+# Process this file with autom4te to create testsuite. -*- Autotest -*-
+
+# Test suite for GNU tar.
+# Copyright 2011 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 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; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+# 02110-1301, USA.
+
+# Check the --owner and --group options.
+
+AT_SETUP([--owner and --group])
+AT_KEYWORDS([owner])
+
+AT_TAR_CHECK([
+export TZ=UTC0
+
+genfile --file a
+
+tar --owner="Joe the Plumber:1234" \
+    --group="Plumber's Union:5678" \
+    --mtime='@0' \
+    -cf arc a
+
+tar -tvf arc
+tar --numeric-owner -tvf arc
+],
+[0],
+[-rw-r--r-- Joe the Plumber/Plumber's Union 0 1970-01-01 00:00 a
+-rw-r--r-- 1234/5678         0 1970-01-01 00:00 a
+],
+[],[],[],[gnu])
+
+AT_CLEANUP
diff --git a/tests/testsuite.at b/tests/testsuite.at
index 9f262ec..35f8c2f 100644
--- a/tests/testsuite.at
+++ b/tests/testsuite.at
@@ -222,6 +222,7 @@ m4_include([multiv07.at])
 m4_include([multiv08.at])

 m4_include([old.at])
+m4_include([owner.at])

 m4_include([recurse.at])