bk commit into 5.1 tree (tsmith:1.2581) BUG#20748

[tim]

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ChangeSet@stripped, 2007-10-16 23:24:08-06:00, tsmith@stripped +1 -0
  Bug #20748: Configuration files should not be read more than once
  
  Change init_default_directories() to remove duplicates from the
  list.
  
  Also, move --sysconfdir=<path> (DEFAULT_SYSCONFDIR) from the end
  to the middle of the list.  $HOME/.my.cnf should be last, so the
  user is able to override the system-wide settings.

  mysys/default.c@stripped, 2007-10-16 23:24:05-06:00, tsmith@stripped +69 -29
    Change order in which defaults files are searched.  Move
    DEFAULT_SYSCONFDIR from the end to the middle (after the hard-
    coded "/etc/" or "C:/", etc.; and before the run-time directories
    (DEFAULT_HOME_ENV, --defaults-extra-file).
    
    Also, don't add duplicate entries in the defaults_directories
    list.  Instead of adding a new duplicate entry, move the
    existing entry to the end of the list.

diff -Nrup a/mysys/default.c b/mysys/default.c
--- a/mysys/default.c	2007-05-10 03:59:25 -06:00
+++ b/mysys/default.c	2007-10-16 23:24:05 -06:00
@@ -960,66 +960,106 @@ static size_t my_get_system_windows_dire
 
 
 /*
-  Create the list of default directories.
+  @brief  Add a single directory to the global default_directories list
 
+  @details  Add the directory to the end of default_directories; if it is
+  already present in the list, move it to the end.
+
+  @param  dir  Directory to add
+
+  @return  void
+*/
+
+static void add_one_default_directory(const char *dir)
+{
+  const char **p;
+  for (p= default_directories; *p; ++p)
+  {
+    if (strcmp(*p, dir) == 0)
+      break;
+  }
+  DBUG_ASSERT(p < default_directories +
+                    array_elements(default_directories) - 1);
+  DBUG_ASSERT(*p == NULL || strcmp(*p, dir) == 0);
+
+  while (*(p + 1))
+  {
+    *p= *(p + 1);
+    ++p;
+  }
+
+  *p= dir;
+}
+
+
+/*
+  @brief Create the list of default directories.
+
+  @details
   On Microsoft Windows, this is:
     1. C:/
     2. GetWindowsDirectory()
     3. GetSystemWindowsDirectory()
-    4. getenv(DEFAULT_HOME_ENV)
-    5. Directory above where the executable is located
-    6. ""
-    7. --sysconfdir=<path>
+    4. --sysconfdir=<path> (compile-time option)
+    5. getenv(DEFAULT_HOME_ENV)
+    6. Directory above where the executable is located
+    7. --defaults-extra-file=<path> (run-time option)
 
   On Novell NetWare, this is:
     1. sys:/etc/
-    2. getenv(DEFAULT_HOME_ENV)
-    3. ""
-    4. --sysconfdir=<path>
+    2. --sysconfdir=<path> (compile-time option)
+    3. getenv(DEFAULT_HOME_ENV)
+    4. --defaults-extra-file=<path> (run-time option)
 
   On OS/2, this is:
     1. getenv(ETC)
     2. /etc/
-    3. getenv(DEFAULT_HOME_ENV)
-    4. ""
-    5. "~/"
-    6. --sysconfdir=<path>
+    3. --sysconfdir=<path> (compile-time option)
+    4. getenv(DEFAULT_HOME_ENV)
+    5. --defaults-extra-file=<path> (run-time option)
+    6. "~/"
 
   Everywhere else, this is:
     1. /etc/
     2. /etc/mysql/
-    3. getenv(DEFAULT_HOME_ENV)
-    4. ""
-    5. "~/"
-    6. --sysconfdir=<path>
+    3. --sysconfdir=<path> (compile-time option)
+    4. getenv(DEFAULT_HOME_ENV)
+    5. --defaults-extra-file=<path> (run-time option)
+    6. "~/"
 
- */
+  On all systems, if a directory is already in the list, it will be moved
+  to the end of the list.  This avoids reading defaults files multiple times,
+  while ensuring the correct precedence.
+
+  @return void
+*/
 
 static void init_default_directories()
 {
   const char *env, **ptr= default_directories;
 
+  bzero(default_directories, sizeof(default_directories));
+
 #ifdef __WIN__
-  *ptr++= "C:/";
+  add_one_default_directory("C:/");
 
   if (GetWindowsDirectory(system_dir,sizeof(system_dir)))
-    *ptr++= (char*)&system_dir;
+    add_one_default_directory((char *)&system_dir);
   if (my_get_system_windows_directory(shared_system_dir,
-                                      sizeof(shared_system_dir)) &&
-      strcmp(system_dir, shared_system_dir))
-    *ptr++= (char *)&shared_system_dir;
+                                      sizeof(shared_system_dir)))
+    add_one_default_directory((char *)&shared_system_dir);
 
 #elif defined(__NETWARE__)
-  *ptr++= "sys:/etc/";
+  add_one_default_directory("sys:/etc/");
 #else
-  *ptr++= "/etc/";
-  *ptr++= "/etc/mysql/";
+  add_one_default_directory("/etc/");
+  add_one_default_directory("/etc/mysql/");
 #endif
   if ((env= getenv(STRINGIFY_ARG(DEFAULT_HOME_ENV))))
-    *ptr++= env;
-  *ptr++= "";			/* Place for defaults_extra_file */
+    add_one_default_directory(env);
+  add_one_default_directory("");			/* Place for defaults_extra_file */
 #if !defined(__WIN__) && !defined(__NETWARE__)
-  *ptr++= "~/";;
+  add_one_default_directory("~/");
 #elif defined(__WIN__)
   if (GetModuleFileName(NULL, config_dir, sizeof(config_dir)))
   {
@@ -1050,7 +1090,7 @@ static void init_default_directories()
         last= end;
       }
     }
-    *ptr++= (char *)&config_dir;
+    add_one_default_directory((char *)&config_dir);
   }
 #endif
 #ifdef DEFAULT_SYSCONFDIR