Add a missing statement, add licensing info and correct coding style

mysys/default_modify.c

+/* Copyright (C) 2005 MySQL AB
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
+
+#include "my_global.h"
+#include "mysys_priv.h"
+#include "m_string.h"
+#include <my_dir.h>
+
+#define BUFF_SIZE 1024
+
+#ifdef __WIN__
+#define NEWLINE "\r\n"
+#define NEWLINE_LEN 2
+#else
+#define NEWLINE "\n"
+#define NEWLINE_LEN 1
+#endif
+
+static char *add_option(char *dst, const char *option_value,
+			const char *option, int remove_option);
+
+
 /*
   Add/remove option to the option file section.
 
@@ -15,6 +50,8 @@
     into a buffer. Then we look for the option within this section and
     change/remove it. In the end we get a buffer with modified version of the
     file. Then we write it to the file, truncate it if needed and close it.
+    Note that there is a small time gap, when the file is incomplete,
+    and this theoretically might introduce a problem.
 
   RETURN
     0 - ok
@@ -22,24 +59,6 @@
     2 - cannot open the file
 */
 
-#include "my_global.h"
-#include "mysys_priv.h"
-#include "m_string.h"
-#include <my_dir.h>
-
-#define BUFF_SIZE 1024
-
-#ifdef __WIN__
-#define NEWLINE "\r\n"
-#define NEWLINE_LEN 2
-#else
-#define NEWLINE "\n"
-#define NEWLINE_LEN 1
-#endif
-
-static char *add_option(char *dst, const char *option_value,
-			const char *option, int remove_option);
-
 int modify_defaults_file(const char *file_location, const char *option,
                          const char *option_value,
                          const char *section_name, int remove_option)
@@ -47,7 +66,7 @@ int modify_defaults_file(const char *file_location, const char *option,
   FILE *cnf_file;
   MY_STAT file_stat;
   char linebuff[BUFF_SIZE], *src_ptr, *dst_ptr, *file_buffer;
-  uint optlen, optval_len, sect_len, nr_newlines= 0;
+  uint opt_len, optval_len, sect_len, nr_newlines= 0;
   my_bool in_section= FALSE, opt_applied= 0;
   DBUG_ENTER("modify_defaults_file");
 
@@ -58,7 +77,7 @@ int modify_defaults_file(const char *file_location, const char *option,
   if (my_fstat(fileno(cnf_file), &file_stat, MYF(0)))
     goto err;
 
-  optlen= (uint) strlen(option);
+  opt_len= (uint) strlen(option);
   optval_len= (uint) strlen(option_value);
 
   /*
@@ -68,15 +87,16 @@ int modify_defaults_file(const char *file_location, const char *option,
   if (!(file_buffer= (char*) my_malloc(sizeof(char) *
                                        (file_stat.st_size +
                                         /* option name len */
-					optlen +
+                                        opt_len +
                                         /* reserve space for newline */
                                         NEWLINE_LEN +
                                         /* reserve for '=' char */
                                         1 +
                                         /* option value len */
                                         optval_len +
-					/* The ending zero plus some safety */
-					FN_REFLEN), MYF(MY_WME))))
+                                        /* The ending zero */
+                                        1), MYF(MY_WME))))
+
     goto malloc_err;
 
   sect_len= (uint) strlen(section_name);
@@ -94,10 +114,11 @@ int modify_defaults_file(const char *file_location, const char *option,
       continue;
     }
 
-    if (!opt_applied && in_section && !strncmp(src_ptr, option, optlen) &&
-	(*(src_ptr + optlen) == '=' ||
-	 my_isspace(&my_charset_latin1, *(src_ptr + optlen)) ||
-	 *(src_ptr + optlen) == '\0'))
+    /* correct the option */
+    if (!opt_applied && in_section && !strncmp(src_ptr, option, opt_len) &&
+        (*(src_ptr + opt_len) == '=' ||
+         my_isspace(&my_charset_latin1, *(src_ptr + opt_len)) ||
+         *(src_ptr + opt_len) == '\0'))
     {
       dst_ptr= add_option(dst_ptr, option_value, option, remove_option);
       opt_applied= 1;
@@ -108,8 +129,9 @@ int modify_defaults_file(const char *file_location, const char *option,
       if (in_section && !opt_applied && *src_ptr == '[')
       {
         dst_ptr= add_option(dst_ptr, option_value, option, remove_option);
-
+        opt_applied= 1;           /* set the flag to do write() later */
       }
+
       for (; nr_newlines; nr_newlines--)
         dst_ptr= strmov(dst_ptr, NEWLINE);
       dst_ptr= strmov(dst_ptr, linebuff);