iwordexp.c

Intercom 是一个 Unix系统上灵活的语音传输软件。支持标准音频压缩比如GSM, G.711, and G.72x和其他音频编码。Intercom专为高速网络设计来传输高品质的语音

  size_t env_maxlen;
  size_t pat_length;
  size_t pat_maxlen;
  size_t start = *offset;
  char *env;
  char *pattern;
  char *value = NULL;
  enum action action = ACT_NONE;
  int depth = 0;
  int colon_seen = 0;
  int seen_hash = 0;
  int free_value = 0;
  int pattern_is_quoted = 0; /* 1 for singly-quoted, 2 for doubly-quoted */
  int error;
  int special = 0;
  char buffer[21];
  int brace = words[*offset] == '{';

  env = w_newword (&env_length, &env_maxlen);
  pattern = w_newword (&pat_length, &pat_maxlen);

  if (brace)
    ++*offset;

  /* First collect the parameter name. */

  if (words[*offset] == '#')
    {
      seen_hash = 1;
      if (!brace)
	goto envsubst;
      ++*offset;
    }

  if (isalpha (words[*offset]) || words[*offset] == '_')
    {
      /* Normal parameter name. */
      do
	{
	  env = w_addchar (env, &env_length, &env_maxlen,
			   words[*offset]);
	  if (env == NULL)
	    goto no_space;
	}
      while (isalnum (words[++*offset]) || words[*offset] == '_');
    }
  else if (isdigit (words[*offset]))
    {
      /* Numeric parameter name. */
      special = 1;
      do
	{
	  env = w_addchar (env, &env_length, &env_maxlen,
			   words[*offset]);
	  if (env == NULL)
	    goto no_space;
	  if (!brace)
	    goto envsubst;
	}
      while (isdigit(words[++*offset]));
    }
  else if (strchr ("*@$", words[*offset]) != NULL)
    {
      /* Special parameter. */
      special = 1;
      env = w_addchar (env, &env_length, &env_maxlen,
		       words[*offset]);
      if (env == NULL)
	goto no_space;
      ++*offset;
    }
  else
    {
      if (brace)
	goto syntax;
    }

  if (brace)
    {
      /* Check for special action to be applied to the value. */
      switch (words[*offset])
	{
	case '}':
	  /* Evaluate. */
	  goto envsubst;

	case '#':
	  action = ACT_RP_SHORT_LEFT;
	  if (words[1 + *offset] == '#')
	    {
	      ++*offset;
	      action = ACT_RP_LONG_LEFT;
	    }
	  break;

	case '%':
	  action = ACT_RP_SHORT_RIGHT;
	  if (words[1 + *offset] == '%')
	    {
	      ++*offset;
	      action = ACT_RP_LONG_RIGHT;
	    }
	  break;

	case ':':
	  if (strchr ("-=?+", words[1 + *offset]) == NULL)
	    goto syntax;

	  colon_seen = 1;
	  action = words[++*offset];
	  break;

	case '-':
	case '=':
	case '?':
	case '+':
	  action = words[*offset];
	  break;

	default:
	  goto syntax;
	}

      /* Now collect the pattern, but don't expand it yet. */
      ++*offset;
      for (; words[*offset]; ++(*offset))
	{
	  switch (words[*offset])
	    {
	    case '{':
	      if (!pattern_is_quoted)
		++depth;
	      break;

	    case '}':
	      if (!pattern_is_quoted)
		{
		  if (depth == 0)
		    goto envsubst;
		  --depth;
		}
	      break;

	    case '\\':
	      if (pattern_is_quoted)
		/* Quoted; treat as normal character. */
		break;

	      /* Otherwise, it's an escape: next character is literal. */
	      if (words[++*offset] == '\0')
		goto syntax;

	      pattern = w_addchar (pattern, &pat_length, &pat_maxlen, '\\');
	      if (pattern == NULL)
		goto no_space;

	      break;

	    case '\'':
	      if (pattern_is_quoted == 0)
		pattern_is_quoted = 1;
	      else if (pattern_is_quoted == 1)
		pattern_is_quoted = 0;

	      break;

	    case '"':
	      if (pattern_is_quoted == 0)
		pattern_is_quoted = 2;
	      else if (pattern_is_quoted == 2)
		pattern_is_quoted = 0;

	      break;
	    }

	  pattern = w_addchar (pattern, &pat_length, &pat_maxlen,
			       words[*offset]);
	  if (pattern == NULL)
	    goto no_space;
	}
    }

  /* End of input string -- remember to reparse the character that we
   * stopped at.  */
  --(*offset);

envsubst:
  if (words[start] == '{' && words[*offset] != '}')
    goto syntax;

  if (env == NULL)
    {
      if (seen_hash)
	{
	  /* $# expands to the number of positional parameters */
	  buffer[20] = '\0';
	  value = itoa_word (0, &buffer[20], 10, 0);
	  seen_hash = 0;
	}
      else
	{
	  /* Just $ on its own */
	  *offset = start - 1;
	  *word = w_addchar (*word, word_length, max_length, '$');
	  return *word ? 0 : WRDE_NOSPACE;
	}
    }
  /* Is it a special parameter? */
  else if (special)
    {
      /* Is it `$$'? */
      if (*env == '$')
	{
	  buffer[20] = '\0';
	  value = itoa_word (getpid (), &buffer[20], 10, 0);
	}
    }
  else
    value = getenv (env);

  if (value == NULL && (flags & WRDE_UNDEF))
    {
      /* Variable not defined. */
      error = WRDE_BADVAL;
      goto do_error;
    }

  if (action != ACT_NONE)
    {
      int expand_pattern = 0;

      /* First, find out if we need to expand pattern (i.e. if we will
       * use it). */
      switch (action)
	{
	case ACT_RP_SHORT_LEFT:
	case ACT_RP_LONG_LEFT:
	case ACT_RP_SHORT_RIGHT:
	case ACT_RP_LONG_RIGHT:
	  /* Always expand for these. */
	  expand_pattern = 1;
	  break;

	case ACT_NULL_ERROR:
	case ACT_NULL_SUBST:
	case ACT_NULL_ASSIGN:
	  if (!value || (!*value && colon_seen))
	    /* If param is unset, or set but null and a colon has been seen,
	       the expansion of the pattern will be needed. */
	    expand_pattern = 1;

	  break;

	case ACT_NONNULL_SUBST:
	  /* Expansion of word will be needed if parameter is set and not null,
	     or set null but no colon has been seen. */
	  if (value && (*value || !colon_seen))
	    expand_pattern = 1;

	  break;

	default:
	  assert (! "Unrecognised action!");
	}

      if (expand_pattern)
	{
	  /* We need to perform tilde expansion, parameter expansion,
             command substitution, and arithmetic expansion.  We also
	     have to be a bit careful with wildcard characters, as
	     pattern might be given to fnmatch soon.  To do this, we
	     convert quotes to escapes. */

	  char *expanded;
	  size_t exp_len;
	  size_t exp_maxl;
	  char *p;
	  int quoted = 0; /* 1: single quotes; 2: double */

	  expanded = w_newword (&exp_len, &exp_maxl);
	  for (p = pattern; p && *p; p++)
	    {
	      size_t offset;

	      switch (*p)
		{
		case '"':
		  if (quoted == 2)
		    quoted = 0;
		  else if (quoted == 0)
		    quoted = 2;
		  else break;

		  continue;

		case '\'':
		  if (quoted == 1)
		    quoted = 0;
		  else if (quoted == 0)
		    quoted = 1;
		  else break;

		  continue;

		case '*':
		case '?':
		  if (quoted)
		    {
		      /* Convert quoted wildchar to escaped wildchar. */
		      expanded = w_addchar (expanded, &exp_len,
					    &exp_maxl, '\\');

		      if (expanded == NULL)
			goto no_space;
		    }
		  break;

		case '$':
		  offset = 0;
		  error = parse_dollars (&expanded, &exp_len, &exp_maxl, p,
					 &offset, flags, NULL, NULL, NULL, 1);
		  if (error)
		    {
		      if (free_value)
			free (value);

		      if (expanded)
			free (expanded);

		      goto do_error;
		    }

		  p += offset;
		  continue;

		case '~':
		  if (quoted || exp_len)
		    break;

		  offset = 0;
		  error = parse_tilde (&expanded, &exp_len, &exp_maxl, p,
				       &offset, 0);
		  if (error)
		    {
		      if (free_value)
			free (value);

		      if (expanded)
			free (expanded);

		      goto do_error;
		    }

		  p += offset;
		  continue;

		case '\\':
		  expanded = w_addchar (expanded, &exp_len, &exp_maxl, '\\');
		  ++p;
		  assert (*p); /* checked when extracted initially */
		  if (expanded == NULL)
		    goto no_space;
		}

	      expanded = w_addchar (expanded, &exp_len, &exp_maxl, *p);

	      if (expanded == NULL)
		goto no_space;
	    }

	  if (pattern)
		  free (pattern);

	  pattern = expanded;
	}

      switch (action)
	{
	case ACT_RP_SHORT_LEFT:
	case ACT_RP_LONG_LEFT:
	case ACT_RP_SHORT_RIGHT:
	case ACT_RP_LONG_RIGHT:
	  {
	    char *p;
	    char c;
	    char *end;

	    if (value == NULL || pattern == NULL || *pattern == '\0')
	      break;

	    end = value + strlen (value);

	    switch (action)
	      {
	      case ACT_RP_SHORT_LEFT:
		for (p = value; p <= end; ++p)
		  {
		    c = *p;
		    *p = '\0';
		    if (fnmatch (pattern, value, 0) != FNM_NOMATCH)
		      {
			*p = c;
			if (free_value)
			  {
			    char *newval = strdup (p);
			    if (newval == NULL)
			      {
				free (value);
				goto no_space;
			      }
			    free (value);
			    value = newval;
			  }
			else
			  value = p;
			break;
		      }
		    *p = c;
		  }

		break;

	      case ACT_RP_LONG_LEFT:
		for (p = end; p >= value; --p)
		  {
		    c = *p;
		    *p = '\0';
		    if (fnmatch (pattern, value, 0) != FNM_NOMATCH)
		      {
			*p = c;
			if (free_value)
			  {
			    char *newval = strdup (p);
			    if (newval == NULL)
			      {
				free (value);
				goto no_space;
			      }
			    free (value);
			    value = newval;
			  }
			else
			  value = p;
			break;
		      }
		    *p = c;
		  }

		break;

	      case ACT_RP_SHORT_RIGHT:
		for (p = end; p >= value; --p)
		  {
		    if (fnmatch (pattern, p, 0) != FNM_NOMATCH)
		      {
			char *newval;
			newval = malloc (p - value + 1);

			if (newval == NULL)
			  {
			    if (free_value)
			      free (value);
			    goto no_space;
			  }

			*(char *) mempcpy (newval, value, p - value) = '\0';
			if (free_value)
			  free (value);
			value = newval;
			free_value = 1;
			break;
		      }
		  }

		break;

	      case ACT_RP_LONG_RIGHT:
		for (p = value; p <= end; ++p)
		  {
		    if (fnmatch (pattern, p, 0) != FNM_NOMATCH)
		      {
			char *newval;
			newval = malloc (p - value + 1);

			if (newval == NULL)
			  {
			    if (free_value)
			      free (value);
			    goto no_space;
			  }

			*(char *) mempcpy (newval, value, p - value) = '\0';
			if (free_value)
			  free (value);
			value = newval;
			free_value = 1;
			break;
		      }
		  }

		break;

	      default:
		break;
	      }

	    break;
	  }

	case ACT_NULL_ERROR:
	  if (value && *value)
	    /* Substitute parameter */
	    break;

	  error = 0;
	  if (!colon_seen && value)
	    /* Substitute NULL */
	    ;
	  else
	    {
	      const char *str = pattern;

	      if (str[0] == '\0')
		str = _("parameter null or not set");

#ifdef USE_IN_LIBIO
	      if (_IO_fwide (stderr, 0) > 0)
		fwprintf (stderr, L"%s: %s\n", env, str);
	      else
#endif
		fprintf (stderr, "%s: %s\n", env, str);
	    }

	  if (free_value)
	    free (value);
	  goto do_error;

	case ACT_NULL_SUBST:
	  if (value && *value)
	    /* Substitute parameter */
	    break;

	  if (free_value && value)
	    free (value);

	  if (!colon_seen && value)
	    /* Substitute NULL */
	    goto success;

	  value = pattern ? strdup (pattern) : pattern;
	  free_value = 1;

	  if (pattern && !value)
	    goto no_space;

	  break;

	case ACT_NONNULL_SUBST:
	  if (value && (*value || !colon_seen))
	    {
	      if (free_value && value)
		free (value);

	      value = pattern ? strdup (pattern) : pattern;
	      free_value = 1;

	      if (pattern && !value)
		goto no_space;

	      break;
	    }

	  /* Substitute NULL */
	  if (free_value)
	    free (value);
	  goto success;

	case ACT_NULL_ASSIGN:
	  if (value && *value)
	    /* Substitute parameter */
	    break;

	  if (!colon_seen && value)
	    {
	      /* Substitute NULL */
	      if (free_value)
		free (value);
	      goto success;
	    }

	  if (free_value && value)
	    free (value);

	  value = pattern ? strdup (pattern) : pattern;
	  free_value = 1;

	  if (pattern && !value)
	    goto no_space;

	  setenv (env, value, 1);
	  break;