BUG#57953 my_load_defaults return junk argument ----args-separator---- to caller

After fix of bug#25192, load_defaults() will add an args separator
to distinguish options loaded from configure files from that provided
in the command line. One problem of this is that the args separator
would be added no matter the application need it or not.

Fixed the problem by adding an option:
  bool my_getopt_use_args_separator;
to control whether the separator will be added or not. And also
added functions:
  bool my_getopt_is_args_separator(const char* arg);
to check if the argument is the separator or not.

1 files changed, 44 insertions, 15 deletions

diff --git a/mysys/default.c b/mysys/default.c
index 75eb4709e1e..432c3086254 100644
--- a/mysys/default.c
+++ b/mysys/default.c
@@ -61,9 +61,23 @@
    check the pointer, use "----args-separator----" here to ease debug
    if someone misused it.
 
+   The args seprator will only be added when
+   my_getopt_use_args_seprator is set to TRUE before calling
+   load_defaults();
+
    See BUG#25192
 */
-const char *args_separator= "----args-separator----";
+static const char *args_separator= "----args-separator----";
+inline static void set_args_separator(char** arg)
+{
+  DBUG_ASSERT(my_getopt_use_args_separator);
+  *arg= (char*)args_separator;
+}
+my_bool my_getopt_use_args_separator= FALSE;
+my_bool my_getopt_is_args_separator(const char* arg)
+{
+  return (arg == args_separator);
+}
 const char *my_defaults_file=0;
 const char *my_defaults_group_suffix=0;
 const char *my_defaults_extra_file=0;
@@ -503,6 +517,7 @@ int my_load_defaults(const char *conf_file, const char **groups,
   char *ptr,**res;
   struct handle_option_ctx ctx;
   const char **dirs;
+  uint args_sep= my_getopt_use_args_separator ? 1 : 0;
   DBUG_ENTER("load_defaults");
 
   init_alloc_root(&alloc,512,0);
@@ -515,17 +530,28 @@ int my_load_defaults(const char *conf_file, const char **groups,
   if (*argc >= 2 && !strcmp(argv[0][1],"--no-defaults"))
   {
     /* remove the --no-defaults argument and return only the other arguments */
-    uint i;
+    uint i, j;
     if (!(ptr=(char*) alloc_root(&alloc,sizeof(alloc)+
 				 (*argc + 1)*sizeof(char*))))
       goto err;
     res= (char**) (ptr+sizeof(alloc));
     res[0]= **argv;				/* Copy program name */
-    /* set arguments separator */
-    res[1]= (char *)args_separator;
-    for (i=2 ; i < (uint) *argc ; i++)
-      res[i]=argv[0][i];
-    res[i]=0;					/* End pointer */
+    j= 1;                 /* Start from 1 for the reset result args */
+    if (my_getopt_use_args_separator)
+    {
+      /* set arguments separator */
+      set_args_separator(&res[1]);
+      j++;
+    }
+    for (i=2 ; i < (uint) *argc ; i++, j++)
+      res[j]=argv[0][i];
+    res[j]=0;					/* End pointer */
+    /*
+      Update the argc, if have not added args separator, then we have
+      to decrease argc because we have removed the "--no-defaults".
+    */
+    if (!my_getopt_use_args_separator)
+      (*argc)--;
     *argv=res;
     *(MEM_ROOT*) ptr= alloc;			/* Save alloc root for free */
     if (default_directories)
@@ -559,7 +585,7 @@ int my_load_defaults(const char *conf_file, const char **groups,
     or a forced default file
   */
   if (!(ptr=(char*) alloc_root(&alloc,sizeof(alloc)+
-			       (args.elements + *argc + 1 + 1) *sizeof(char*))))
+			       (args.elements + *argc + 1 + args_sep) *sizeof(char*))))
     goto err;
   res= (char**) (ptr+sizeof(alloc));
 
@@ -580,16 +606,19 @@ int my_load_defaults(const char *conf_file, const char **groups,
     --*argc; ++*argv;				/* skip argument */
   }
 
-  /* set arguments separator for arguments from config file and
-     command line */
-  res[args.elements+1]= (char *)args_separator;
+  if (my_getopt_use_args_separator)
+  {
+    /* set arguments separator for arguments from config file and
+       command line */
+    set_args_separator(&res[args.elements+1]);
+  }
 
   if (*argc)
-    memcpy((uchar*) (res+1+args.elements+1), (char*) ((*argv)+1),
+    memcpy((uchar*) (res+1+args.elements+args_sep), (char*) ((*argv)+1),
 	   (*argc-1)*sizeof(char*));
-  res[args.elements+ *argc+1]=0;                /* last null */
+  res[args.elements+ *argc+args_sep]=0;                /* last null */
 
-  (*argc)+=args.elements+1;
+  (*argc)+=args.elements+args_sep;
   *argv= (char**) res;
   *(MEM_ROOT*) ptr= alloc;			/* Save alloc root for free */
   delete_dynamic(&args);
@@ -599,7 +628,7 @@ int my_load_defaults(const char *conf_file, const char **groups,
     printf("%s would have been started with the following arguments:\n",
 	   **argv);
     for (i=1 ; i < *argc ; i++)
-      if ((*argv)[i] != args_separator) /* skip arguments separator */
+      if (!my_getopt_is_args_separator((*argv)[i])) /* skip arguments separator */
         printf("%s ", (*argv)[i]);
     puts("");
     exit(0);