Bug#45288: pb2 returns a lot of compilation warnings on linux

Fix warnings flagged by the new warning option -Wunused-but-set-variable
that was added to GCC 4.6 and that is enabled by -Wunused and -Wall. The
option causes a warning whenever a local variable is assigned to but is
later unused. It also warns about meaningless pointer dereferences.

client/mysql.cc:
  Meaningless pointer dereferences.
client/mysql_upgrade.c:
  Check whether reading from the file succeeded.
extra/comp_err.c:
  Unused.
extra/yassl/src/yassl_imp.cpp:
  Skip instead of reading data that is discarded.
include/my_pthread.h:
  Variable is only used in debug builds.
include/mysys_err.h:
  Add new error messages.
mysys/errors.c:
  Add new error message for permission related functions.
mysys/mf_iocache.c:
  Variable is only checked under THREAD.
mysys/my_copy.c:
  Raise a error if chmod or chown fails.
mysys/my_redel.c:
  Raise a error if chmod or chown fails.
regex/engine.c:
  Use a equivalent variable for the assert.
server-tools/instance-manager/instance_options.cc:
  Unused.
sql/field.cc:
  Unused.
sql/item.cc:
  Unused.
sql/log.cc:
  Do not ignore the return value of freopen: only set buffer if
  reopening succeeds.
  
  Adjust doxygen comment to the right function.
  
  Pass message lenght to log function.
sql/mysqld.cc:
  Do not ignore the return value of freopen: only set buffer if
  reopening succeeds.
sql/partition_info.cc:
  Unused.
sql/slave.cc:
  No need to set pointer to the address of '\0'.
sql/spatial.cc:
  Unused. Left for historical purposes.
sql/sql_acl.cc:
  Unused.
sql/sql_base.cc:
  Pointers are always set to the same variables.
sql/sql_parse.cc:
  End statement if reading fails.
  
  Store the buffer after it has actually been updated.
sql/sql_repl.cc:
  No need to set pointer to the address of '\0'.
sql/sql_show.cc:
  Put variable under the same ifdef block.
sql/udf_example.c:
  Set null pointer flag appropriately.
storage/csv/ha_tina.cc:
  Meaningless dereferences.
storage/example/ha_example.cc:
  Return the error since it's available.
storage/myisam/mi_locking.c:
  Remove unused and dead code.

16 files changed, 73 insertions, 90 deletions

diff --git a/sql/field.cc b/sql/field.cc
index c648b53e139..c887a5f1c9b 100644
--- a/sql/field.cc
+++ b/sql/field.cc
@@ -5541,7 +5541,6 @@ int Field_date::store(const char *from, uint len,CHARSET_INFO *cs)
 int Field_date::store(double nr)
 {
   longlong tmp;
-  int error= 0;
   if (nr >= 19000000000000.0 && nr <= 99991231235959.0)
     nr=floor(nr/1000000.0);			// Timestamp to date
   if (nr < 0.0 || nr > 99991231.0)
@@ -5550,7 +5549,6 @@ int Field_date::store(double nr)
     set_datetime_warning(MYSQL_ERROR::WARN_LEVEL_WARN,
                          ER_WARN_DATA_OUT_OF_RANGE,
                          nr, MYSQL_TIMESTAMP_DATE);
-    error= 1;
   }
   else
     tmp= (longlong) rint(nr);
diff --git a/sql/item.cc b/sql/item.cc
index db2c4c0974b..66c5314c16e 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -255,11 +255,10 @@ my_decimal *Item::val_decimal_from_int(my_decimal *decimal_value)
 my_decimal *Item::val_decimal_from_string(my_decimal *decimal_value)
 {
   String *res;
-  char *end_ptr;
+
   if (!(res= val_str(&str_value)))
-    return 0;                                   // NULL or EOM
+    return NULL;
 
-  end_ptr= (char*) res->ptr()+ res->length();
   if (str2my_decimal(E_DEC_FATAL_ERROR & ~E_DEC_BAD_NUM,
                      res->ptr(), res->length(), res->charset(),
                      decimal_value) & E_DEC_BAD_NUM)
diff --git a/sql/log.cc b/sql/log.cc
index d8d5f6fa418..614a07e6b63 100644
--- a/sql/log.cc
+++ b/sql/log.cc
@@ -5050,6 +5050,22 @@ void sql_perror(const char *message)
 }
 
 
+/*
+  Unfortunately, there seems to be no good way
+  to restore the original streams upon failure.
+*/
+static bool redirect_std_streams(const char *file)
+{
+  if (freopen(file, "a+", stdout) && freopen(file, "a+", stderr))
+  {
+    setbuf(stderr, NULL);
+    return FALSE;
+  }
+
+  return TRUE;
+}
+
+
 bool flush_error_log()
 {
   bool result=0;
@@ -5077,11 +5093,7 @@ bool flush_error_log()
       setbuf(stderr, NULL);
       (void) my_delete(err_renamed, MYF(0));
       my_rename(log_error_file,err_renamed,MYF(0));
-      if (freopen(log_error_file,"a+",stdout))
-      {
-        freopen(log_error_file,"a+",stderr);
-        setbuf(stderr, NULL);
-      }
+      redirect_std_streams(log_error_file);
 
       if ((fd = my_open(err_temp, O_RDONLY, MYF(0))) >= 0)
       {
@@ -5096,13 +5108,7 @@ bool flush_error_log()
      result= 1;
 #else
    my_rename(log_error_file,err_renamed,MYF(0));
-   if (freopen(log_error_file,"a+",stdout))
-   {
-     FILE *reopen;
-     reopen= freopen(log_error_file,"a+",stderr);
-     setbuf(stderr, NULL);
-   }
-   else
+   if (redirect_std_streams(log_error_file))
      result= 1;
 #endif
     VOID(pthread_mutex_unlock(&LOCK_error_log));
@@ -5153,25 +5159,9 @@ static void print_buffer_to_nt_eventlog(enum loglevel level, char *buff,
 #endif /* __NT__ */
 
 
-/**
-  Prints a printf style message to the error log and, under NT, to the
-  Windows event log.
-
-  This function prints the message into a buffer and then sends that buffer
-  to other functions to write that message to other logging sources.
-
-  @param event_type          Type of event to write (Error, Warning, or Info)
-  @param format              Printf style format of message
-  @param args                va_list list of arguments for the message
-
-  @returns
-    The function always returns 0. The return value is present in the
-    signature to be compatible with other logging routines, which could
-    return an error (e.g. logging to the log tables)
-*/
-
 #ifndef EMBEDDED_LIBRARY
-static void print_buffer_to_file(enum loglevel level, const char *buffer)
+static void print_buffer_to_file(enum loglevel level, const char *buffer,
+                                 size_t length)
 {
   time_t skr;
   struct tm tm_tmp;
@@ -5185,7 +5175,7 @@ static void print_buffer_to_file(enum loglevel level, const char *buffer)
   localtime_r(&skr, &tm_tmp);
   start=&tm_tmp;
 
-  fprintf(stderr, "%02d%02d%02d %2d:%02d:%02d [%s] %s\n",
+  fprintf(stderr, "%02d%02d%02d %2d:%02d:%02d [%s] %.*s\n",
           start->tm_year % 100,
           start->tm_mon+1,
           start->tm_mday,
@@ -5194,7 +5184,7 @@ static void print_buffer_to_file(enum loglevel level, const char *buffer)
           start->tm_sec,
           (level == ERROR_LEVEL ? "ERROR" : level == WARNING_LEVEL ?
            "Warning" : "Note"),
-          buffer);
+          (int) length, buffer);
 
   fflush(stderr);
 
@@ -5202,7 +5192,22 @@ static void print_buffer_to_file(enum loglevel level, const char *buffer)
   DBUG_VOID_RETURN;
 }
 
+/**
+  Prints a printf style message to the error log and, under NT, to the
+  Windows event log.
 
+  This function prints the message into a buffer and then sends that buffer
+  to other functions to write that message to other logging sources.
+
+  @param level          The level of the msg significance
+  @param format         Printf style format of message
+  @param args           va_list list of arguments for the message
+
+  @returns
+    The function always returns 0. The return value is present in the
+    signature to be compatible with other logging routines, which could
+    return an error (e.g. logging to the log tables)
+*/
 int vprint_msg_to_log(enum loglevel level, const char *format, va_list args)
 {
   char   buff[1024];
@@ -5210,7 +5215,7 @@ int vprint_msg_to_log(enum loglevel level, const char *format, va_list args)
   DBUG_ENTER("vprint_msg_to_log");
 
   length= my_vsnprintf(buff, sizeof(buff), format, args);
-  print_buffer_to_file(level, buff);
+  print_buffer_to_file(level, buff, length);
 
 #ifdef __NT__
   print_buffer_to_nt_eventlog(level, buff, length, sizeof(buff));
@@ -5218,7 +5223,7 @@ int vprint_msg_to_log(enum loglevel level, const char *format, va_list args)
 
   DBUG_RETURN(0);
 }
-#endif /*EMBEDDED_LIBRARY*/
+#endif /* EMBEDDED_LIBRARY */
 
 
 void sql_print_error(const char *format, ...) 
diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index 99f16b36dfa..fda64e5a1ea 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -3783,7 +3783,6 @@ static void end_ssl()
 
 static int init_server_components()
 {
-  FILE* reopen;
   DBUG_ENTER("init_server_components");
   /*
     We need to call each of these following functions to ensure that
@@ -3826,8 +3825,8 @@ static int init_server_components()
       if (freopen(log_error_file, "a+", stdout))
 #endif
       {
-        reopen= freopen(log_error_file, "a+", stderr);
-        setbuf(stderr, NULL);
+        if (freopen(log_error_file, "a+", stderr))
+          setbuf(stderr, NULL);
       }
     }
   }
@@ -8222,7 +8221,7 @@ mysqld_get_one_option(int optid,
     *val= 0;
     val+= 2;
     while (*val && my_isspace(mysqld_charset, *val))
-      *val++;
+      val++;
     if (!*val)
     {
       sql_print_error("Bad syntax in replicate-rewrite-db - empty TO db!\n");
diff --git a/sql/partition_info.cc b/sql/partition_info.cc
index d85888e295c..f37151ea51d 100644
--- a/sql/partition_info.cc
+++ b/sql/partition_info.cc
@@ -1206,13 +1206,11 @@ bool partition_info::set_up_charset_field_preps()
     i= 0;
     while ((field= *(ptr++)))
     {
-      CHARSET_INFO *cs;
       uchar *field_buf;
       LINT_INIT(field_buf);
 
       if (!field_is_partition_charset(field))
         continue;
-      cs= ((Field_str*)field)->charset();
       size= field->pack_length();
       if (!(field_buf= (uchar*) sql_calloc(size)))
         goto error;
diff --git a/sql/slave.cc b/sql/slave.cc
index 795bc481071..f1e0962e7e8 100644
--- a/sql/slave.cc
+++ b/sql/slave.cc
@@ -3035,11 +3035,8 @@ log '%s' at position %s, relay log '%s' position: %s", RPL_LOG_NAME,
   pthread_mutex_lock(&rli->data_lock);
   if (rli->slave_skip_counter)
   {
-    char *pos;
-    pos= strmake(saved_log_name, rli->group_relay_log_name, FN_REFLEN - 1);
-    pos= '\0';
-    pos= strmake(saved_master_log_name, rli->group_master_log_name, FN_REFLEN - 1);
-    pos= '\0';
+    strmake(saved_log_name, rli->group_relay_log_name, FN_REFLEN - 1);
+    strmake(saved_master_log_name, rli->group_master_log_name, FN_REFLEN - 1);
     saved_log_pos= rli->group_relay_log_pos;
     saved_master_log_pos= rli->group_master_log_pos;
     saved_skip= rli->slave_skip_counter;
diff --git a/sql/spatial.cc b/sql/spatial.cc
index 11df6c00dc5..2305a8eb97d 100644
--- a/sql/spatial.cc
+++ b/sql/spatial.cc
@@ -159,11 +159,10 @@ Geometry *Geometry::construct(Geometry_buffer *buffer,
 {
   uint32 geom_type;
   Geometry *result;
-  char byte_order;
 
   if (data_len < SRID_SIZE + WKB_HEADER_SIZE)   // < 4 + (1 + 4)
     return NULL;
-  byte_order= data[SRID_SIZE];
+  /* + 1 to skip the byte order (stored in position SRID_SIZE). */
   geom_type= uint4korr(data + SRID_SIZE + 1);
   if (!(result= create_by_typeid(buffer, (int) geom_type)))
     return NULL;
diff --git a/sql/sql_acl.cc b/sql/sql_acl.cc
index 90eef872115..b507b70d1fb 100644
--- a/sql/sql_acl.cc
+++ b/sql/sql_acl.cc
@@ -5701,7 +5701,6 @@ bool mysql_create_user(THD *thd, List <LEX_USER> &list)
 {
   int result;
   String wrong_users;
-  ulong sql_mode;
   LEX_USER *user_name, *tmp_user_name;
   List_iterator <LEX_USER> user_list(list);
   TABLE_LIST tables[GRANT_TABLES];
@@ -5748,7 +5747,6 @@ bool mysql_create_user(THD *thd, List <LEX_USER> &list)
     }
 
     some_users_created= TRUE;
-    sql_mode= thd->variables.sql_mode;
     if (replace_user_table(thd, tables[0].table, *user_name, 0, 0, 1, 0))
     {
       append_user(&wrong_users, user_name);
diff --git a/sql/sql_base.cc b/sql/sql_base.cc
index d2392bdd9b1..c38526a6d0b 100644
--- a/sql/sql_base.cc
+++ b/sql/sql_base.cc
@@ -5674,7 +5674,7 @@ static void update_field_dependencies(THD *thd, Field *field, TABLE *table)
   DBUG_ENTER("update_field_dependencies");
   if (thd->mark_used_columns != MARK_COLUMNS_NONE)
   {
-    MY_BITMAP *current_bitmap, *other_bitmap;
+    MY_BITMAP *bitmap;
 
     /*
       We always want to register the used keys, as the column bitmap may have
@@ -5685,15 +5685,9 @@ static void update_field_dependencies(THD *thd, Field *field, TABLE *table)
     table->merge_keys.merge(field->part_of_key);
 
     if (thd->mark_used_columns == MARK_COLUMNS_READ)
-    {
-      current_bitmap= table->read_set;
-      other_bitmap=   table->write_set;
-    }
+      bitmap= table->read_set;
     else
-    {
-      current_bitmap= table->write_set;
-      other_bitmap=   table->read_set;
-    }
+      bitmap= table->write_set;
 
     /* 
        The test-and-set mechanism in the bitmap is not reliable during
@@ -5702,7 +5696,7 @@ static void update_field_dependencies(THD *thd, Field *field, TABLE *table)
        only those columns that are used in the SET clause. I.e they are being
        set here. See multi_update::prepare()
     */
-    if (bitmap_fast_test_and_set(current_bitmap, field->field_index))
+    if (bitmap_fast_test_and_set(bitmap, field->field_index))
     {
       if (thd->mark_used_columns == MARK_COLUMNS_WRITE)
       {
diff --git a/sql/sql_load.cc b/sql/sql_load.cc
index ee7481234a4..a4cf46b35e8 100644
--- a/sql/sql_load.cc
+++ b/sql/sql_load.cc
@@ -128,6 +128,7 @@ int mysql_load(THD *thd,sql_exchange *ex,TABLE_LIST *table_list,
   bool is_fifo=0;
 #ifndef EMBEDDED_LIBRARY
   LOAD_FILE_INFO lf_info;
+  THD::killed_state killed_status;
 #endif
   char *db = table_list->db;			// This is never null
   /*
@@ -138,7 +139,6 @@ int mysql_load(THD *thd,sql_exchange *ex,TABLE_LIST *table_list,
   char *tdb= thd->db ? thd->db : db;		// Result is never null
   ulong skip_lines= ex->skip_lines;
   bool transactional_table;
-  THD::killed_state killed_status= THD::NOT_KILLED;
   DBUG_ENTER("mysql_load");
 
 #ifdef EMBEDDED_LIBRARY
@@ -455,7 +455,11 @@ int mysql_load(THD *thd,sql_exchange *ex,TABLE_LIST *table_list,
                     error=1;
                     thd->killed= THD::KILL_QUERY;
                   };);
-  killed_status= (error == 0)? THD::NOT_KILLED : thd->killed;
+
+#ifndef EMBEDDED_LIBRARY
+  killed_status= (error == 0) ? THD::NOT_KILLED : thd->killed;
+#endif
+
   /*
     We must invalidate the table in query cache before binlog writing and
     ha_autocommit_...
@@ -708,12 +712,9 @@ read_fixed_length(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
   List_iterator_fast<Item> it(fields_vars);
   Item_field *sql_field;
   TABLE *table= table_list->table;
-  ulonglong id;
   bool err;
   DBUG_ENTER("read_fixed_length");
 
-  id= 0;
- 
   while (!read_info.read_fixed_length())
   {
     if (thd->killed)
@@ -839,12 +840,10 @@ read_sep_field(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
   Item *item;
   TABLE *table= table_list->table;
   uint enclosed_length;
-  ulonglong id;
   bool err;
   DBUG_ENTER("read_sep_field");
 
   enclosed_length=enclosed.length();
-  id= 0;
 
   for (;;it.rewind())
   {
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index 1f3d29ffec0..134517e5bf7 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -465,6 +465,12 @@ static void handle_bootstrap_impl(THD *thd)
       }
       buff= (char*) thd->net.buff;
       res= fgets(buff + length, thd->net.max_packet - length, file);
+      if (!res && !feof(file))
+      {
+        net_end_statement(thd);
+        bootstrap_error= 1;
+        break;
+      }
       length+= (ulong) strlen(buff + length);
       /* purecov: end */
     }
@@ -1535,7 +1541,7 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
   {
     STATUS_VAR current_global_status_var;
     ulong uptime;
-    uint length;
+    uint length __attribute__((unused));
     ulonglong queries_per_second1000;
     char buff[250];
     uint buff_len= sizeof(buff);
@@ -1548,7 +1554,7 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
     else
       queries_per_second1000= thd->query_id * LL(1000) / uptime;
 
-    length= my_snprintf((char*) buff, buff_len - 1,
+    length= my_snprintf(buff, buff_len - 1,
                         "Uptime: %lu  Threads: %d  Questions: %lu  "
                         "Slow queries: %lu  Opens: %lu  Flush tables: %lu  "
                         "Open tables: %u  Queries per second avg: %u.%u",
@@ -1560,10 +1566,6 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
                         cached_open_tables(),
                         (uint) (queries_per_second1000 / 1000),
                         (uint) (queries_per_second1000 % 1000));
-#ifdef EMBEDDED_LIBRARY
-    /* Store the buffer in permanent memory */
-    my_ok(thd, 0, 0, buff);
-#endif
 #ifdef SAFEMALLOC
     if (sf_malloc_cur_memory)				// Using SAFEMALLOC
     {
@@ -1578,6 +1580,9 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
     VOID(my_net_write(net, (uchar*) buff, length));
     VOID(net_flush(net));
     thd->main_da.disable_status();
+#else
+    /* Store the buffer in permanent memory */
+    my_ok(thd, 0, 0, buff);
 #endif
     break;
   }
diff --git a/sql/sql_repl.cc b/sql/sql_repl.cc
index f6045e4704e..d7dd3eb63f2 100644
--- a/sql/sql_repl.cc
+++ b/sql/sql_repl.cc
@@ -1168,12 +1168,9 @@ bool change_master(THD* thd, Master_info* mi)
   /*
     Before processing the command, save the previous state.
   */
-  char *pos;
-  pos= strmake(saved_host, mi->host, HOSTNAME_LENGTH);
-  pos= '\0';
+  strmake(saved_host, mi->host, HOSTNAME_LENGTH);
   saved_port= mi->port;
-  pos= strmake(saved_log_name, mi->master_log_name, FN_REFLEN - 1);
-  pos= '\0';
+  strmake(saved_log_name, mi->master_log_name, FN_REFLEN - 1);
   saved_log_pos= mi->master_log_pos;
 
   /*
diff --git a/sql/sql_show.cc b/sql/sql_show.cc
index d0e76e501e2..eb5d3a1965d 100644
--- a/sql/sql_show.cc
+++ b/sql/sql_show.cc
@@ -3868,7 +3868,6 @@ static int get_schema_column_record(THD *thd, TABLE_LIST *tables,
     uint flags=field->flags;
     char tmp[MAX_FIELD_WIDTH];
     String type(tmp,sizeof(tmp), system_charset_info);
-    char *end;
     int decimals, field_length;
 
     if (wild && wild[0] &&
@@ -3889,7 +3888,7 @@ static int get_schema_column_record(THD *thd, TABLE_LIST *tables,
                                  field->field_name) & COL_ACLS;
     if (!tables->schema_table && !col_access)
       continue;
-    end= tmp;
+    char *end= tmp;
     for (uint bitnr=0; col_access ; col_access>>=1,bitnr++)
     {
       if (col_access & 1)
@@ -4015,7 +4014,6 @@ static int get_schema_column_record(THD *thd, TABLE_LIST *tables,
     table->field[15]->store((const char*) pos,
                             strlen((const char*) pos), cs);
 
-    end= tmp;
     if (field->unireg_check == Field::NEXT_NUMBER)
       table->field[16]->store(STRING_WITH_LEN("auto_increment"), cs);
     if (show_table->timestamp_field == field &&
diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index 47b91fcca0e..f765e5c5cae 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -6507,7 +6507,6 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
   uint index_add_count= 0;
   uint *index_add_buffer= NULL;
   uint candidate_key_count= 0;
-  bool committed= 0;
   bool no_pk;
   DBUG_ENTER("mysql_alter_table");
 
@@ -7380,7 +7379,6 @@ view_err:
     DBUG_PRINT("info", ("Committing before unlocking table"));
     if (ha_autocommit_or_rollback(thd, 0) || end_active_trans(thd))
       goto err1;
-    committed= 1;
   }
   /*end of if (! new_table) for add/drop index*/
 
diff --git a/sql/table.cc b/sql/table.cc
index dde3654dab1..e989ab039a0 100644
--- a/sql/table.cc
+++ b/sql/table.cc
@@ -534,7 +534,7 @@ int open_table_def(THD *thd, TABLE_SHARE *share, uint db_flags)
   int error, table_type;
   bool error_given;
   File file;
-  uchar head[288], *disk_buff;
+  uchar head[288];
   char	path[FN_REFLEN];
   MEM_ROOT **root_ptr, *old_root;
   DBUG_ENTER("open_table_def");
@@ -543,7 +543,6 @@ int open_table_def(THD *thd, TABLE_SHARE *share, uint db_flags)
 
   error= 1;
   error_given= 0;
-  disk_buff= NULL;
 
   strxmov(path, share->normalized_path.str, reg_ext, NullS);
   if ((file= my_open(path, O_RDONLY | O_SHARE, MYF(0))) < 0)
diff --git a/sql/udf_example.c b/sql/udf_example.c
index 637293209e0..468118b44ef 100644
--- a/sql/udf_example.c
+++ b/sql/udf_example.c
@@ -1067,7 +1067,7 @@ char *myfunc_argument_name(UDF_INIT *initid __attribute__((unused)),
 {
   if (!args->attributes[0])
   {
-    null_value= 0;
+    *null_value= 1;
     return 0;
   }
   (*length)--; /* space for ending \0 (for debugging purposes) */