2.11BSD#431 - /usr/src/libexec/tcpd/percent_x.c

   1:  /*
   2:   * percent_x() takes a string and performs %<char> expansions. It aborts the
   3:   * program when the expansion would overflow the output buffer. The result
   4:   * of %<char> expansion may be passed on to a shell process. For this
   5:   * reason, characters with a special meaning to shells are replaced by
   6:   * underscores.
   7:   *
   8:   * Diagnostics are reported through syslog(3).
   9:   *
  10:   * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
  11:   */
  12: 
  13: #ifndef lint
  14: static char sccsid[] = "@(#) percent_x.c 1.4 94/12/28 17:42:37";
  15: #endif
  16: 
  17: /* System libraries. */
  18: 
  19: #include <stdio.h>
  20: #include <syslog.h>
  21: #include <string.h>
  22: 
  23: extern void exit();
  24: 
  25: /* Local stuff. */
  26: 
  27: #include "tcpd.h"
  28: 
  29: /* percent_x - do %<char> expansion, abort if result buffer is too small */
  30: 
  31: char   *percent_x(result, result_len, string, request)
  32: char   *result;
  33: int     result_len;
  34: char   *string;
  35: struct request_info *request;
  36: {
  37:     char   *bp = result;
  38:     char   *end = result + result_len - 1;  /* end of result buffer */
  39:     char   *expansion;
  40:     int     expansion_len;
  41:     static char ok_chars[] = "1234567890!@%-_=+:,./\
  42: abcdefghijklmnopqrstuvwxyz\
  43: ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  44:     char   *str = string;
  45:     char   *cp;
  46:     int     ch;
  47: 
  48:     /*
  49:      * Warning: we may be called from a child process or after pattern
  50:      * matching, so we cannot use clean_exit() or tcpd_jump().
  51:      */
  52: 
  53:     while (*str) {
  54:     if (*str == '%' && (ch = str[1]) != 0) {
  55:         str += 2;
  56:         expansion =
  57:         ch == 'a' ? eval_hostaddr(request->client) :
  58:         ch == 'A' ? eval_hostaddr(request->server) :
  59:         ch == 'c' ? eval_client(request) :
  60:         ch == 'd' ? eval_daemon(request) :
  61:         ch == 'h' ? eval_hostinfo(request->client) :
  62:         ch == 'H' ? eval_hostinfo(request->server) :
  63:         ch == 'n' ? eval_hostname(request->client) :
  64:         ch == 'N' ? eval_hostname(request->server) :
  65:         ch == 'p' ? eval_pid(request) :
  66:         ch == 's' ? eval_server(request) :
  67:         ch == 'u' ? eval_user(request) :
  68:         ch == '%' ? "%" : (tcpd_warn("unrecognized %%%c", ch), "");
  69:         for (cp = expansion; *(cp += strspn(cp, ok_chars)); /* */ )
  70:         *cp = '_';
  71:         expansion_len = cp - expansion;
  72:     } else {
  73:         expansion = str++;
  74:         expansion_len = 1;
  75:     }
  76:     if (bp + expansion_len >= end) {
  77:         tcpd_warn("percent_x: expansion too long: %.30s...", result);
  78:         sleep(5);
  79:         exit(0);
  80:     }
  81:     memcpy(bp, expansion, expansion_len);
  82:     bp += expansion_len;
  83:     }
  84:     *bp = 0;
  85:     return (result);
  86: }

Defined functions

Defined variables