1 files changed, 69 insertions, 46 deletions

diff --git a/mysys/default_modify.c b/mysys/default_modify.c
index add4317bb56..721ca596428 100644
--- a/mysys/default_modify.c
+++ b/mysys/default_modify.c
@@ -37,22 +37,20 @@
 #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)
 {
   FILE *cnf_file;
   MY_STAT file_stat;
-  char linebuff[BUFF_SIZE], tmp[BUFF_SIZE], *tmp_ptr, *src_ptr, *dst_ptr,
-       *file_buffer;
-  uint optlen, optval_len, sect_len;
-  my_bool in_section= FALSE;
+  char linebuff[BUFF_SIZE], *src_ptr, *dst_ptr, *file_buffer;
+  uint optlen, optval_len, sect_len, nr_newlines= 0;
+  my_bool in_section= FALSE, opt_applied= 0;
   DBUG_ENTER("modify_defaults_file");
 
-  optlen= strlen(option);
-  optval_len= strlen(option_value);
-  sect_len= strlen(section_name);
-
   if (!(cnf_file= my_fopen(file_location, O_RDWR | O_BINARY, MYF(0))))
     DBUG_RETURN(2);
 
@@ -60,12 +58,15 @@ int modify_defaults_file(const char *file_location, const char *option,
   if (my_fstat(fileno(cnf_file), &file_stat, MYF(0)))
     goto err;
 
+  optlen= strlen(option);
+  optval_len= strlen(option_value);
+
   /*
     Reserve space to read the contents of the file and some more
     for the option we want to add.
   */
-  if (!(file_buffer= (char*) my_malloc(sizeof(char)*
-				       (file_stat.st_size +
+  if (!(file_buffer= (char*) my_malloc(sizeof(char) *
+				       (file_stat.st_size + 
 					/* option name len */
 					optlen +
 					/* reserve space for newline */
@@ -73,35 +74,44 @@ int modify_defaults_file(const char *file_location, const char *option,
 					/* reserve for '=' char */
 					1 +           
 					/* option value len */
-					optval_len), MYF(MY_WME))))
+					optval_len +
+					/* The ending zero plus some safety */
+					FN_REFLEN), MYF(MY_WME))))
     goto malloc_err;
 
-  for (dst_ptr= file_buffer, tmp_ptr= 0;
-       fgets(linebuff, BUFF_SIZE, cnf_file); )
+  sect_len= strlen(section_name);
+
+  for (dst_ptr= file_buffer; fgets(linebuff, BUFF_SIZE, cnf_file); )
   {
     /* Skip over whitespaces */
     for (src_ptr= linebuff; my_isspace(&my_charset_latin1, *src_ptr);
 	 src_ptr++)
     {}
 
-    if (in_section && !strncmp(src_ptr, option, optlen) &&
+    if (!*src_ptr) /* Empty line */
+    {
+      nr_newlines++;
+      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'))
     {
-      /* The option under modifying was found in this section. Apply new. */
-      if (!remove_option)
-	dst_ptr= strmov(dst_ptr, tmp);
-      tmp_ptr= 0; /* To mark that we have already applied this */
+      dst_ptr= add_option(dst_ptr, option_value, option, remove_option);
+      opt_applied= 1;
     }
     else
     {
       /* If going to new group and we have option to apply, do it now */
-      if (tmp_ptr && *src_ptr == '[')
+      if (in_section && !opt_applied && *src_ptr == '[')
       {
-	dst_ptr= strmov(dst_ptr, tmp);
-	tmp_ptr= 0;
+	dst_ptr= add_option(dst_ptr, option_value, option, remove_option);
+
       }
+      for (; nr_newlines; nr_newlines--)
+	dst_ptr= strmov(dst_ptr, NEWLINE);	
       dst_ptr= strmov(dst_ptr, linebuff);
     }
     /* Look for a section */
@@ -117,43 +127,38 @@ int modify_defaults_file(const char *file_location, const char *option,
 
 	if (*src_ptr != ']')
 	  continue; /* Missing closing parenthesis. Assume this was no group */
-	
         in_section= TRUE;
-        /* add option */
-        if (!remove_option)
-        {
-          tmp_ptr= strmov(tmp, option);
-          if (*option_value)
-          {
-	    *tmp_ptr++= '=';
-            tmp_ptr= strmov(tmp_ptr, option_value);
-          }
-          /* add a newline */
-	  strmov(tmp_ptr, NEWLINE);
-        }
       }
       else
         in_section= FALSE; /* mark that this section is of no interest to us */
     }
   }
-  /* File ended. New option still remains to apply at the end */
-  if (tmp_ptr)
+  /* File ended. */
+  if (!opt_applied && !remove_option && in_section)
   {
+    /* New option still remains to apply at the end */
     if (*(dst_ptr - 1) != '\n')
-      *dst_ptr++= '\n';
-    dst_ptr= strmov(dst_ptr, tmp);    
+      dst_ptr= strmov(dst_ptr, NEWLINE);
+    dst_ptr= add_option(dst_ptr, option_value, option, remove_option);
+    opt_applied= 1;
   }
+  for (; nr_newlines; nr_newlines--)
+    dst_ptr= strmov(dst_ptr, NEWLINE);
 
-  if (my_chsize(fileno(cnf_file), (my_off_t) (dst_ptr - file_buffer), 0,
-		MYF(MY_WME)) ||
-      my_fseek(cnf_file, 0, MY_SEEK_SET, MYF(0)) ||
-      my_fwrite(cnf_file, file_buffer, (uint) (dst_ptr - file_buffer),
-		MYF(MY_NABP)) ||
-      my_fclose(cnf_file, MYF(MY_WME)))
-     goto err;
+  if (opt_applied)
+  {
+    /* Don't write the file if there are no changes to be made */
+    if (my_chsize(fileno(cnf_file), (my_off_t) (dst_ptr - file_buffer), 0,
+		  MYF(MY_WME)) ||
+	my_fseek(cnf_file, 0, MY_SEEK_SET, MYF(0)) ||
+	my_fwrite(cnf_file, file_buffer, (uint) (dst_ptr - file_buffer),
+		  MYF(MY_NABP)))
+      goto err;
+  }
+  if (my_fclose(cnf_file, MYF(MY_WME)))
+    goto err;
 
   my_free(file_buffer, MYF(0));
-
   DBUG_RETURN(0);
 
 err:
@@ -162,3 +167,21 @@ malloc_err:
   my_fclose(cnf_file, MYF(0));
   DBUG_RETURN(1); /* out of resources */
 }
+
+
+static char *add_option(char *dst, const char *option_value,
+			const char *option, int remove_option)
+{
+  if (!remove_option)
+  {
+    dst= strmov(dst, option);
+    if (*option_value)
+    {
+      *dst++= '=';
+      dst= strmov(dst, option_value);
+    }
+    /* add a newline */
+    dst= strmov(dst, NEWLINE);
+  }
+  return dst;
+}