crash in command_interpreter() with part of Unicode-characters

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4 months 3 days ago #10028 by Pacifist
I found that part of command_interpreter() cause crash with such commands like "ю", "юю" etc. It's occur there:
  /* special case to handle one-character, non-alphanumeric commands; requested
   * by many people so "'hi" or ";godnet test" is possible. Patch sent by Eric
   * Green and Stefan Wasilewski. */
  if (!isalpha(*argument)) {
    arg[0] = argument[0];
    arg[1] = '\0';
    line = argument + 1;
  } else
    line = any_one_arg(argument, arg);

How can I repair that?

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4 months 3 days ago #10029 by thomas
This is a special case where your characters trigger the "not alphanumeric" check. I figure this results in garbage in the resulting values.
The fix is to rewrite to using iswalpha instead, though I'm not sure how to go about it here.

Have you altered the code significantly to support utf-8 by now?

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4 months 3 days ago #10030 by Pacifist
Have you altered the code significantly to support utf-8 by now?

I'm use only this modification:
github.com/prool/tbamud/blob/7790abec579...590/src/comm.c#L1965

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4 months 2 days ago #10031 by thomas
Ok, I understand why this happens now (thanks for the link to the code, it really helped). The issue is that the isalpha check returns false for the koi characters (are they utf-8-encoded here? I think so).
Instead of
 if (!isalpha(*argument)) {
I suggest you be explicit like this:
// somewhere near the function.
const char specialSingleChars = "*';";

 if (strchr(specialSingleChars, *argument) != NULL) {

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4 months 2 days ago #10032 by Pacifist
interpreter.c: In function ‘command_interpreter’:
interpreter.c:488:35: warning: initialization of ‘char’ from ‘char *’ makes integer from pointer without a cast [-Wint-conversion]
  488 |   const char specialSingleChars = "*';";
      |                                   ^~~~~
interpreter.c:500:14: warning: passing argument 1 of ‘strchr’ makes pointer from integer without a cast [-Wint-conversion]
  500 |   if (strchr(specialSingleChars, *argument) != NULL) {
      |              ^~~~~~~~~~~~~~~~~~
      |              |
      |              char
In file included from sysdep.h:74,
                 from interpreter.c:12:
/usr/include/string.h:226:14: note: expected ‘const char *’ but argument is of type ‘char’
  226 | extern char *strchr (const char *__s, int __c)
      |              ^~~~~~
And TbaMUD crashed soon after run.

I'm not programmer but think that problem in "ю" that it wide character and occupy more than argument[0].

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4 months 2 days ago #10033 by thomas
Ah yes, a typical browser code slip.
Missed a * there.
const char *specialSingleChars = "*';";

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3 months 4 weeks ago #10034 by Pacifist
Thanks. It working now.

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