bk commit into 5.0 tree (aelkin:1.2543) BUG#28597

[Andrei Elkin]

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5.0 repository of elkin. When elkin does a push these changes will
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ChangeSet@stripped, 2007-10-25 12:05:57+03:00, aelkin@stripped +2 -0
  Bug #28597 Replication doesn't start after upgrading to 5.1.18
  
  Since bug@20166, which replaced the binlog file name generating to base on pidfile_name
instead of 
  the previous glob_hostname, the binlog file name generating and its storing into the
binlog index
  suddenly started to be solely in the absolute path format,
  including a case when --log-bin option meant a relative path.
  
  An existed algorithm on master to find a requested binlog file for slave was limited to
compare only
  homogenous paths either absolute or relative but never mixed. 
  In effect of two facts if --log-bin value means a relative path, comparison on the buggy
5.1.18 of an
  allways absolute value (read from the index) with a relave  was doomed.
  
  Fixed with leaving `pidfile_name' but stripping off its directory part that restores the
original logics
  of storing the names in compatible with --log-bin option format.
  The comparison algorithm is refined to be able match any format two paths converting
them to the absolute
  paths.
  
  Two side effects for this fix:
  
  correcting bug#27070;
  ensuring no overrun for buff can happen anymore (Bug #31836 
  insufficient space reserved for the suffix of relay log file name);

  mysql-test/t/rpl_dual_pos_advance.test@stripped, 2007-10-25 12:05:54+03:00,
aelkin@stripped +0 -6
    After correcting the logics of log file name composing workaround for
    
      Bug #27070 server logs are created unrequested and in wrong directory
    
    is removed.

  sql/log.cc@stripped, 2007-10-25 12:05:54+03:00, aelkin@stripped +36 -10
    stripping off the directory part of `pidfile_name' for binlog name generating;
    a new function static bool equalp_paths() compares two paths;
    ensuring no overrun for buff can happen anymore (Bug #31836 
    insufficient space reserved for the suffix of relay log file name)

diff -Nrup a/mysql-test/t/rpl_dual_pos_advance.test
b/mysql-test/t/rpl_dual_pos_advance.test
--- a/mysql-test/t/rpl_dual_pos_advance.test	2007-03-20 12:15:14 +02:00
+++ b/mysql-test/t/rpl_dual_pos_advance.test	2007-10-25 12:05:54 +03:00
@@ -106,9 +106,3 @@ connection slave;
 sync_with_master;
 
 # End of 4.1 tests
-
-# Cleanup
-# The A->B->A replication causes the master to start writing relay logs
-# in var/run, remove them
-remove_file $MYSQLTEST_VARDIR/run/master-relay-bin.000001;
-remove_file $MYSQLTEST_VARDIR/run/master-relay-bin.index;
diff -Nrup a/sql/log.cc b/sql/log.cc
--- a/sql/log.cc	2007-07-30 18:27:30 +03:00
+++ b/sql/log.cc	2007-10-25 12:05:54 +03:00
@@ -448,13 +448,11 @@ const char *MYSQL_LOG::generate_name(con
 {
   if (!log_name || !log_name[0])
   {
-    /*
-      TODO: The following should be using fn_format();  We just need to
-      first change fn_format() to cut the file name if it's too long.
-    */
-    strmake(buff, pidfile_name,FN_REFLEN-5);
-    strmov(fn_ext(buff),suffix);
-    return (const char *)buff;
+    strmake(buff, pidfile_name, FN_REFLEN - strlen(suffix) - 1);
+    return (const char *)
+      fn_format(buff, buff, "", suffix,
+                MYF(MY_UNPACK_FILENAME|MY_REPLACE_EXT|MY_REPLACE_DIR));
+
   }
   // get rid of extension if the log is binary to avoid problems
   if (strip_ext)
@@ -796,6 +794,33 @@ err:
 #endif /* HAVE_REPLICATION */
 
 /*
+  Compare two arbitrary paths represented as null-terminated strings.
+  If a path arg is relative then `abs_root' absolute path provides the
+  necessary contribution to build the absolute path out of the path arg.
+
+  SYNOPSIS
+    equalp_paths()
+    
+    path_a, path_b  being compared paths
+    abs_root        an absolute root path
+
+  RETURN VALUES
+  TRUE if the paths are equal, otherwise FALSE
+ */
+static bool equalp_paths(const char *path_a,  const char *path_b,
+                         const char *abs_root= mysql_real_data_home)
+{
+  size_t len;
+  uint flag= MYF(MY_RETURN_REAL_PATH|MY_RESOLVE_SYMLINKS);
+  char abs_path_a[2*FN_REFLEN];
+  char abs_path_b[2*FN_REFLEN];
+  fn_format(abs_path_a, path_a, abs_root, "", flag);
+  fn_format(abs_path_b, path_b, abs_root, "", flag);
+  return ((len= strlen(abs_path_a)) == strlen(abs_path_b) && 
+          memcmp(abs_path_a, abs_path_b, len) == 0);
+}
+
+/*
   Find the position in the log-index-file for the given log name
 
   SYNOPSIS
@@ -852,11 +877,12 @@ int MYSQL_LOG::find_log_pos(LOG_INFO *li
 
     // if the log entry matches, null string matching anything
     if (!log_name ||
-	(log_name_len == length-1 && fname[log_name_len] == '\n' &&
-	 !memcmp(fname, log_name, log_name_len)))
+        (fname[length - 1] == '\n' &&
+         !(fname[length - 1]= 0)  &&
+         equalp_paths(log_name, fname)))
     {
       DBUG_PRINT("info",("Found log file entry"));
-      fname[length-1]=0;			// remove last \n
+      fname[length - 1]= 0;
       linfo->index_file_start_offset= offset;
       linfo->index_file_offset = my_b_tell(&index_file);
       break;