Merge pchardin@bk-internal.mysql.com:/home/bk/mysql-5.0

into mysql.com:/home/cps/mysql/trees/mysql-5.0

mysys/default_modify.c

@@ -20,6 +20,8 @@
 #include <my_dir.h>
 
 #define BUFF_SIZE 1024
+/* should be big enough to handle at least one line */
+#define RESERVE 1024
 
 #ifdef __WIN__
 #define NEWLINE "\r\n"
@@ -66,8 +68,11 @@ 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 opt_len, optval_len, sect_len, nr_newlines= 0;
+  uint opt_len, optval_len, sect_len, nr_newlines= 0, buffer_size;
   my_bool in_section= FALSE, opt_applied= 0;
+  uint reserve_extended= 1, old_opt_len= 0;
+  uint new_opt_len;
+  int reserve_occupied= 0;
   DBUG_ENTER("modify_defaults_file");
 
   if (!(cnf_file= my_fopen(file_location, O_RDWR | O_BINARY, MYF(0))))
@@ -75,28 +80,33 @@ int modify_defaults_file(const char *file_location, const char *option,
 
   /* my_fstat doesn't use the flag parameter */
   if (my_fstat(fileno(cnf_file), &file_stat, MYF(0)))
-    goto err;
+    goto malloc_err;
 
   opt_len= (uint) strlen(option);
   optval_len= (uint) strlen(option_value);
 
+  new_opt_len= opt_len + 1 + optval_len + NEWLINE_LEN;
+
+  /* calculate the size of the buffer we need */
+  buffer_size= sizeof(char) * (file_stat.st_size +
+                               /* option name len */
+                               opt_len +
+                               /* reserve for '=' char */
+                               1 +
+                               /* option value len */
+                               optval_len +
+                               /* reserve space for newline */
+                               NEWLINE_LEN +
+                               /* The ending zero */
+                               1 +
+                               /* reserve some additional space */
+                               RESERVE);
+
   /*
     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 +
-                                        /* option name len */
-                                        opt_len +
-                                        /* reserve space for newline */
-                                        NEWLINE_LEN +
-                                        /* reserve for '=' char */
-                                        1 +
-                                        /* option value len */
-                                        optval_len +
-                                        /* The ending zero */
-                                        1), MYF(MY_WME))))
-
+  if (!(file_buffer= (char*) my_malloc(buffer_size, MYF(MY_WME))))
     goto malloc_err;
 
   sect_len= (uint) strlen(section_name);
@@ -115,13 +125,37 @@ int modify_defaults_file(const char *file_location, const char *option,
     }
 
     /* correct the option */
-    if (!opt_applied && in_section && !strncmp(src_ptr, option, opt_len) &&
+    if (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'))
     {
+      /*
+        we should change all options. If opt_applied is set, we are running
+        into reserved memory area. Hence we should check for overruns.
+      */
+      if (opt_applied)
+      {
+        src_ptr+= opt_len; /* If we correct an option, we know it's name */
+        old_opt_len= opt_len;
+
+        while (*src_ptr++) /* Find the end of the line */
+          old_opt_len++;
+
+        /* could be negative */
+        reserve_occupied+= (int) new_opt_len - (int) old_opt_len;
+        if ((int) reserve_occupied > (int) (RESERVE*reserve_extended))
+        {
+          if (!(file_buffer= (char*) my_realloc(file_buffer, buffer_size +
+                                                RESERVE*reserve_extended,
+                                                MYF(MY_WME|MY_FREE_ON_ERROR))))
+            goto malloc_err;
+          reserve_extended++;
+        }
+      }
+      else
+        opt_applied= 1;
       dst_ptr= add_option(dst_ptr, option_value, option, remove_option);
-      opt_applied= 1;
     }
     else
     {