MDEV-5226 mysql_tzinfo_to_sql errors with tzdata 2013f and above

Allow only one level of symlink recursion in mysql_tzdata_to_sql,
to avoid infinite loops.

mysql-test/Makefile.am

@@ -78,7 +78,7 @@ EXTRA_DIST =	README README.suites \
 TEST_DIRS = t r include std_data std_data/parts collections \
 	std_data/ndb_backup50 std_data/ndb_backup51 \
 	std_data/ndb_backup51_data_be std_data/ndb_backup51_data_le \
-	std_data/funcs_1 \
+	std_data/funcs_1 std_data/zoneinfo \
 	extra/binlog_tests/ extra/rpl_tests \
 	suite/binlog suite/binlog/t suite/binlog/r suite/binlog/std_data \
 	suite/federated \

mysql-test/mysql-test-run.pl

@@ -2298,6 +2298,13 @@ sub environment_setup {
 				 "$path_client_bindir/perror");
   $ENV{'MY_PERROR'}= native_path($exe_perror);
 
+  # ----------------------------------------------------
+  # mysql_tzinfo_to_sql
+  # ----------------------------------------------------
+  my $exe_mysql_tzinfo_to_sql= mtr_exe_exists("$basedir/sql$opt_vs_config/mysql_tzinfo_to_sql",
+				 "$path_client_bindir/mysql_tzinfo_to_sql");
+  $ENV{'MYSQL_TZINFO_TO_SQL'}= native_path($exe_mysql_tzinfo_to_sql);
+
   # Create an environment variable to make it possible
   # to detect that valgrind is being used from test cases
   $ENV{'VALGRIND_TEST'}= $opt_valgrind;

mysql-test/r/mysql_tzinfo_to_sql_symlink.result

+#
+# MDEV-5226 mysql_tzinfo_to_sql errors with tzdata 2013f and above
+#
+TRUNCATE TABLE time_zone;
+TRUNCATE TABLE time_zone_name;
+TRUNCATE TABLE time_zone_transition;
+TRUNCATE TABLE time_zone_transition_type;
+INSERT INTO time_zone (Use_leap_seconds) VALUES ('N');
+SET @time_zone_id= LAST_INSERT_ID();
+INSERT INTO time_zone_name (Name, Time_zone_id) VALUES ('GMT', @time_zone_id);
+INSERT INTO time_zone_transition_type (Time_zone_id, Transition_type_id, Offset, Is_DST, Abbreviation) VALUES
+ (@time_zone_id, 0, 0, 0, 'GMT')
+;
+INSERT INTO time_zone (Use_leap_seconds) VALUES ('N');
+SET @time_zone_id= LAST_INSERT_ID();
+INSERT INTO time_zone_name (Name, Time_zone_id) VALUES ('posix/GMT', @time_zone_id);
+INSERT INTO time_zone_transition_type (Time_zone_id, Transition_type_id, Offset, Is_DST, Abbreviation) VALUES
+ (@time_zone_id, 0, 0, 0, 'GMT')
+;
+Warning: Skipping directory 'MYSQLTEST_VARDIR/zoneinfo/posix/posix': to avoid infinite symlink recursion.
+ALTER TABLE time_zone_transition ORDER BY Time_zone_id, Transition_time;
+ALTER TABLE time_zone_transition_type ORDER BY Time_zone_id, Transition_type_id;

mysql-test/t/mysql_tzinfo_to_sql_symlink.test

+--source include/have_symlink.inc
+--source include/not_windows.inc
+
+--echo #
+--echo # MDEV-5226 mysql_tzinfo_to_sql errors with tzdata 2013f and above
+--echo #
+
+--exec mkdir $MYSQLTEST_VARDIR/zoneinfo
+--exec ln -s $MYSQLTEST_VARDIR/zoneinfo $MYSQLTEST_VARDIR/zoneinfo/posix
+--copy_file std_data/zoneinfo/GMT $MYSQLTEST_VARDIR/zoneinfo/GMT
+
+--replace_result $MYSQLTEST_VARDIR MYSQLTEST_VARDIR
+--exec $MYSQL_TZINFO_TO_SQL $MYSQLTEST_VARDIR/zoneinfo 2>&1
+
+--exec rm -rf $MYSQLTEST_VARDIR/zoneinfo

sql/tztime.cc

@@ -2433,7 +2433,7 @@ char *root_name_end;
 
 */
 my_bool
-scan_tz_dir(char * name_end)
+scan_tz_dir(char * name_end, uint symlink_recursion_level)
 {
   MY_DIR *cur_dir;
   char *name_end_tmp;
@@ -2453,7 +2453,32 @@ scan_tz_dir(char * name_end)
 
       if (MY_S_ISDIR(cur_dir->dir_entry[i].mystat->st_mode))
       {
-        if (scan_tz_dir(name_end_tmp))
+        my_bool is_symlink;
+        if ((is_symlink= my_is_symlink(fullname)) &&
+            symlink_recursion_level > 0)
+        {
+          /*
+            The timezone definition data in some Linux distributions
+             (e.g. the "timezone-data-2013f" package in Gentoo)
+            may have synlimks like:
+              /usr/share/zoneinfo/posix/ -> /usr/share/zoneinfo/,
+            so the same timezone files are available under two names
+            (e.g. "CET" and "posix/CET").
+
+            We allow one level of symlink recursion for backward
+            compatibility with earlier timezone data packages that have
+            duplicate copies of the same timezone files inside the root
+            directory and the "posix" subdirectory (instead of symlinking).
+            This makes "posix/CET" still available, but helps to avoid
+            following such symlinks infinitely:
+              /usr/share/zoneinfo/posix/posix/posix/.../posix/
+          */
+          fflush(stdout);
+          fprintf(stderr, "Warning: Skipping directory '%s': "
+                          "to avoid infinite symlink recursion.\n", fullname);
+          continue;
+        }
+        if (scan_tz_dir(name_end_tmp, symlink_recursion_level + is_symlink))
         {
           my_dirend(cur_dir);
           return 1;
@@ -2465,14 +2490,20 @@ scan_tz_dir(char * name_end)
         if (!tz_load(fullname, &tz_info, &tz_storage))
           print_tz_as_sql(root_name_end + 1, &tz_info);
         else
+        {
+          fflush(stdout);
           fprintf(stderr,
                   "Warning: Unable to load '%s' as time zone. Skipping it.\n",
                   fullname);
+        }
         free_root(&tz_storage, MYF(0));
       }
       else
+      {
+        fflush(stdout);
         fprintf(stderr, "Warning: '%s' is not regular file or directory\n",
                 fullname);
+      }
     }
   }
 
@@ -2506,8 +2537,9 @@ main(int argc, char **argv)
     printf("TRUNCATE TABLE time_zone_transition;\n");
     printf("TRUNCATE TABLE time_zone_transition_type;\n");
 
-    if (scan_tz_dir(root_name_end))
+    if (scan_tz_dir(root_name_end, 0))
     {
+      fflush(stdout);
       fprintf(stderr, "There were fatal errors during processing "
                       "of zoneinfo directory\n");
       return 1;
@@ -2526,6 +2558,7 @@ main(int argc, char **argv)
     {
       if (tz_load(argv[2], &tz_info, &tz_storage))
       {
+        fflush(stdout);
         fprintf(stderr, "Problems with zoneinfo file '%s'\n", argv[2]);
         return 1;
       }
@@ -2535,6 +2568,7 @@ main(int argc, char **argv)
     {
       if (tz_load(argv[1], &tz_info, &tz_storage))
       {
+        fflush(stdout);
         fprintf(stderr, "Problems with zoneinfo file '%s'\n", argv[2]);
         return 1;
       }