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.

4 files changed, 47 insertions, 14 deletions

diff --git a/mysys/errors.c b/mysys/errors.c
index 8d3303cac9f..a5ad4a956ab 100644
--- a/mysys/errors.c
+++ b/mysys/errors.c
@@ -49,7 +49,9 @@ const char * NEAR globerrs[GLOBERRS]=
   "Can't sync file '%s' to disk (Errcode: %d)",
   "Collation '%s' is not a compiled collation and is not specified in the '%s' file",
   "File '%s' not found (Errcode: %d)",
-  "File '%s' (fileno: %d) was not closed"
+  "File '%s' (fileno: %d) was not closed",
+  "Can't change ownership of the file '%s' (Errcode: %d)",
+  "Can't change permissions of the file '%s' (Errcode: %d)",
 };
 
 void init_glob_errs(void)
@@ -90,6 +92,8 @@ void init_glob_errs()
   EE(EE_UNKNOWN_COLLATION)= "Collation '%s' is not a compiled collation and is not specified in the %s file";
   EE(EE_FILENOTFOUND)	= "File '%s' not found (Errcode: %d)";
   EE(EE_FILE_NOT_CLOSED) = "File '%s' (fileno: %d) was not closed";
+  EE(EE_CHANGE_OWNERSHIP)   = "Can't change ownership of the file '%s' (Errcode: %d)";
+  EE(EE_CHANGE_PERMISSIONS) = "Can't change permissions of the file '%s' (Errcode: %d)";
 }
 #endif
 
diff --git a/mysys/mf_iocache.c b/mysys/mf_iocache.c
index 1a47982b221..e9b947b04a6 100644
--- a/mysys/mf_iocache.c
+++ b/mysys/mf_iocache.c
@@ -1701,16 +1701,19 @@ int my_block_write(register IO_CACHE *info, const uchar *Buffer, size_t Count,
 #endif
 
 
-int my_b_flush_io_cache(IO_CACHE *info, int need_append_buffer_lock)
+int my_b_flush_io_cache(IO_CACHE *info,
+                        int need_append_buffer_lock __attribute__((unused)))
 {
   size_t length;
-  my_bool append_cache;
   my_off_t pos_in_file;
+  my_bool append_cache= (info->type == SEQ_READ_APPEND);
   DBUG_ENTER("my_b_flush_io_cache");
   DBUG_PRINT("enter", ("cache: 0x%lx", (long) info));
 
-  if (!(append_cache = (info->type == SEQ_READ_APPEND)))
-    need_append_buffer_lock=0;
+#ifdef THREAD
+  if (!append_cache)
+    need_append_buffer_lock= 0;
+#endif
 
   if (info->type == WRITE_CACHE || append_cache)
   {
diff --git a/mysys/my_copy.c b/mysys/my_copy.c
index 418e2b6f8a2..d0c1fc29229 100644
--- a/mysys/my_copy.c
+++ b/mysys/my_copy.c
@@ -16,6 +16,7 @@
 #include "mysys_priv.h"
 #include <my_dir.h> /* for stat */
 #include <m_string.h>
+#include "mysys_err.h"
 #if defined(HAVE_UTIME_H)
 #include <utime.h>
 #elif defined(HAVE_SYS_UTIME_H)
@@ -56,7 +57,6 @@ int my_copy(const char *from, const char *to, myf MyFlags)
   File from_file,to_file;
   uchar buff[IO_SIZE];
   MY_STAT stat_buff,new_stat_buff;
-  int res;
   DBUG_ENTER("my_copy");
   DBUG_PRINT("my",("from %s to %s MyFlags %d", from, to, MyFlags));
 
@@ -102,9 +102,23 @@ int my_copy(const char *from, const char *to, myf MyFlags)
 
     if (MyFlags & MY_HOLD_ORIGINAL_MODES && !new_file_stat)
 	DBUG_RETURN(0);			/* File copyed but not stat */
-    res= chmod(to, stat_buff.st_mode & 07777); /* Copy modes */
+    /* Copy modes */
+    if (chmod(to, stat_buff.st_mode & 07777))
+    {
+      my_errno= errno;
+      if (MyFlags & (MY_FAE+MY_WME))
+        my_error(EE_CHANGE_PERMISSIONS, MYF(ME_BELL+ME_WAITTANG), from, errno);
+      goto err;
+    }
 #if !defined(__WIN__) && !defined(__NETWARE__)
-    res= chown(to, stat_buff.st_uid,stat_buff.st_gid); /* Copy ownership */
+    /* Copy ownership */
+    if (chown(to, stat_buff.st_uid,stat_buff.st_gid))
+    {
+      my_errno= errno;
+      if (MyFlags & (MY_FAE+MY_WME))
+        my_error(EE_CHANGE_OWNERSHIP, MYF(ME_BELL+ME_WAITTANG), from, errno);
+      goto err;
+    }
 #endif
 #if !defined(VMS) && !defined(__ZTC__)
     if (MyFlags & MY_COPYTIME)
diff --git a/mysys/my_redel.c b/mysys/my_redel.c
index 6521253f949..4013c5c8323 100644
--- a/mysys/my_redel.c
+++ b/mysys/my_redel.c
@@ -76,11 +76,8 @@ end:
 int my_copystat(const char *from, const char *to, int MyFlags)
 {
   struct stat statbuf;
-#if !defined(__WIN__) && !defined(__NETWARE__)
-  int res;
-#endif
 
-  if (stat((char*) from, &statbuf))
+  if (stat(from, &statbuf))
   {
     my_errno=errno;
     if (MyFlags & (MY_FAE+MY_WME))
@@ -89,7 +86,15 @@ int my_copystat(const char *from, const char *to, int MyFlags)
   }
   if ((statbuf.st_mode & S_IFMT) != S_IFREG)
     return 1;
-  VOID(chmod(to, statbuf.st_mode & 07777));		/* Copy modes */
+
+  /* Copy modes */
+  if (chmod(to, statbuf.st_mode & 07777))
+  {
+    my_errno= errno;
+    if (MyFlags & (MY_FAE+MY_WME))
+      my_error(EE_CHANGE_PERMISSIONS, MYF(ME_BELL+ME_WAITTANG), from, errno);
+    return -1;
+  }
 
 #if !defined(__WIN__) && !defined(__NETWARE__)
   if (statbuf.st_nlink > 1 && MyFlags & MY_LINK_WARNING)
@@ -97,7 +102,14 @@ int my_copystat(const char *from, const char *to, int MyFlags)
     if (MyFlags & MY_LINK_WARNING)
       my_error(EE_LINK_WARNING,MYF(ME_BELL+ME_WAITTANG),from,statbuf.st_nlink);
   }
-  res= chown(to, statbuf.st_uid, statbuf.st_gid);	/* Copy ownership */
+  /* Copy ownership */
+  if (chown(to, statbuf.st_uid, statbuf.st_gid))
+  {
+    my_errno= errno;
+    if (MyFlags & (MY_FAE+MY_WME))
+      my_error(EE_CHANGE_OWNERSHIP, MYF(ME_BELL+ME_WAITTANG), from, errno);
+    return -1;
+  }
 #endif /* !__WIN__ && !__NETWARE__ */
 
 #ifndef VMS