external/ibm-public/postfix/dist/src/smtpd/smtpd_token.c

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      smtpd_token 3
   6 /* SUMMARY
   7 /*      tokenize SMTPD command
   8 /* SYNOPSIS
   9 /*      #include <smtpd_token.h>
  10 /*
  11 /*      typedef struct {
  12 /* .in +4
  13 /*          int tokval;
  14 /*          char *strval;
  15 /*          /* other stuff... */
  16 /* .in -4
  17 /*      } SMTPD_TOKEN;
  18 /*
  19 /*      int     smtpd_token(str, argvp)
  20 /*      char    *str;
  21 /*      SMTPD_TOKEN **argvp;
  22 /* DESCRIPTION
  23 /*      smtpd_token() routine converts the string in \fIstr\fR to an
  24 /*      array of tokens in \fIargvp\fR. The number of tokens is returned
  25 /*      via the function return value.
  26 /*
  27 /*      Token types:
  28 /* .IP SMTPD_TOK_OTHER
  29 /*      The token is something else.
  30 /* .IP SMTPD_TOK_ERROR
  31 /*      A malformed token.
  32 /* BUGS
  33 /*      This tokenizer understands just enough to tokenize SMTPD commands.
  34 /*      It understands backslash escapes, white space, quoted strings,
  35 /*      and addresses (including quoted text) enclosed by < and >.
  36 /*      The input is broken up into tokens by whitespace, except for
  37 /*      whitespace that is protected by quotes etc.
  38 /* LICENSE
  39 /* .ad
  40 /* .fi
  41 /*      The Secure Mailer license must be distributed with this software.
  42 /* AUTHOR(S)
  43 /*      Wietse Venema
  44 /*      IBM T.J. Watson Research
  45 /*      P.O. Box 704
  46 /*      Yorktown Heights, NY 10598, USA
  47 /*--*/
  48
  49 /* System library. */
  50
  51 #include <sys_defs.h>
  52 #include <ctype.h>
  53 #include <string.h>
  54 #include <unistd.h>
  55
  56 #ifdef STRCASECMP_IN_STRINGS_H
  57 #include <strings.h>
  58 #endif
  59
  60 /* Utility library. */
  61
  62 #include <mymalloc.h>
  63 #include <mvect.h>
  64
  65 /* Application-specific. */
  66
  67 #include "smtpd_token.h"
  68
  69 /* smtp_quoted - read until closing quote */
  70
  71 static char *smtp_quoted(char *cp, SMTPD_TOKEN *arg, int start, int last)
  72 {
  73     static VSTRING *stack;
  74     int     wanted;
  75     int     c;
  76
  77     /*
  78      * Parser stack. `ch' is always the most-recently entered character.
  79      */
  80 #define ENTER_CHAR(buf, ch) VSTRING_ADDCH(buf, ch);
  81 #define LEAVE_CHAR(buf, ch) { \
  82         vstring_truncate(buf, VSTRING_LEN(buf) - 1); \
  83         ch = vstring_end(buf)[-1]; \
  84     }
  85
  86     if (stack == 0)
  87         stack = vstring_alloc(1);
  88     VSTRING_RESET(stack);
  89     ENTER_CHAR(stack, wanted = last);
  90
  91     VSTRING_ADDCH(arg->vstrval, start);
  92     for (;;) {
  93         if ((c = *cp) == 0)
  94             break;
  95         cp++;
  96         VSTRING_ADDCH(arg->vstrval, c);
  97         if (c == '\\') {                        /* parse escape sequence */
  98             if ((c = *cp) == 0)
  99                 break;
 100             cp++;
 101             VSTRING_ADDCH(arg->vstrval, c);
 102         } else if (c == wanted) {               /* closing quote etc. */
 103             if (VSTRING_LEN(stack) == 1)
 104                 return (cp);
 105             LEAVE_CHAR(stack, wanted);
 106         } else if (c == '"') {
 107             ENTER_CHAR(stack, wanted = '"');    /* highest precedence */
 108         } else if (c == '<' && wanted == '>') {
 109             ENTER_CHAR(stack, wanted = '>');    /* lowest precedence */
 110         }
 111     }
 112     arg->tokval = SMTPD_TOK_ERROR;              /* missing end */
 113     return (cp);
 114 }
 115
 116 /* smtp_next_token - extract next token from input, update cp */
 117
 118 static char *smtp_next_token(char *cp, SMTPD_TOKEN *arg)
 119 {
 120     int     c;
 121
 122     VSTRING_RESET(arg->vstrval);
 123     arg->tokval = SMTPD_TOK_OTHER;
 124
 125 #define STR(x) vstring_str(x)
 126 #define LEN(x) VSTRING_LEN(x)
 127 #define STREQ(x,y,l) (strncasecmp((x), (y), (l)) == 0)
 128
 129     for (;;) {
 130         if ((c = *cp) == 0)                     /* end of input */
 131             break;
 132         cp++;
 133         if (ISSPACE(c)) {                       /* whitespace, skip */
 134             while (*cp && ISSPACE(*cp))
 135                 cp++;
 136             if (LEN(arg->vstrval) > 0)          /* end of token */
 137                 break;
 138         } else if (c == '<') {                  /* <stuff> */
 139             cp = smtp_quoted(cp, arg, c, '>');
 140         } else if (c == '"') {                  /* "stuff" */
 141             cp = smtp_quoted(cp, arg, c, c);
 142         } else if (c == ':') {                  /* this is gross, but... */
 143             VSTRING_ADDCH(arg->vstrval, c);
 144             if (STREQ(STR(arg->vstrval), "to:", LEN(arg->vstrval))
 145                 || STREQ(STR(arg->vstrval), "from:", LEN(arg->vstrval)))
 146                 break;
 147         } else {                                /* other */
 148             if (c == '\\') {
 149                 VSTRING_ADDCH(arg->vstrval, c);
 150                 if ((c = *cp) == 0)
 151                     break;
 152                 cp++;
 153             }
 154             VSTRING_ADDCH(arg->vstrval, c);
 155         }
 156     }
 157     if (LEN(arg->vstrval) <= 0)                 /* no token found */
 158         return (0);
 159     VSTRING_TERMINATE(arg->vstrval);
 160     arg->strval = vstring_str(arg->vstrval);
 161     return (cp);
 162 }
 163
 164 /* smtpd_token_init - initialize token structures */
 165
 166 static void smtpd_token_init(char *ptr, int count)
 167 {
 168     SMTPD_TOKEN *arg;
 169     int     n;
 170
 171     for (arg = (SMTPD_TOKEN *) ptr, n = 0; n < count; arg++, n++)
 172         arg->vstrval = vstring_alloc(10);
 173 }
 174
 175 /* smtpd_token - tokenize SMTPD command */
 176
 177 int     smtpd_token(char *cp, SMTPD_TOKEN **argvp)
 178 {
 179     static SMTPD_TOKEN *smtp_argv;
 180     static MVECT mvect;
 181     int     n;
 182
 183     if (smtp_argv == 0)
 184         smtp_argv = (SMTPD_TOKEN *) mvect_alloc(&mvect, sizeof(*smtp_argv), 1,
 185                                             smtpd_token_init, (MVECT_FN) 0);
 186     for (n = 0; /* void */ ; n++) {
 187         smtp_argv = (SMTPD_TOKEN *) mvect_realloc(&mvect, n + 1);
 188         if ((cp = smtp_next_token(cp, smtp_argv + n)) == 0)
 189             break;
 190     }
 191     *argvp = smtp_argv;
 192     return (n);
 193 }
 194
 195 #ifdef TEST
 196
 197  /*
 198   * Test program for the SMTPD command tokenizer.
 199   */
 200
 201 #include <stdlib.h>
 202 #include <vstream.h>
 203 #include <vstring_vstream.h>
 204
 205 int     main(int unused_argc, char **unused_argv)
 206 {
 207     VSTRING *vp = vstring_alloc(10);
 208     int     tok_argc;
 209     SMTPD_TOKEN *tok_argv;
 210     int     i;
 211
 212     for (;;) {
 213         if (isatty(STDIN_FILENO))
 214             vstream_printf("enter SMTPD command: ");
 215         vstream_fflush(VSTREAM_OUT);
 216         if (vstring_get_nonl(vp, VSTREAM_IN) == VSTREAM_EOF)
 217             break;
 218         if (*vstring_str(vp) == '#')
 219             continue;
 220         if (!isatty(STDIN_FILENO))
 221             vstream_printf("%s\n", vstring_str(vp));
 222         tok_argc = smtpd_token(vstring_str(vp), &tok_argv);
 223         for (i = 0; i < tok_argc; i++) {
 224             vstream_printf("Token type:  %s\n",
 225                            tok_argv[i].tokval == SMTPD_TOK_OTHER ? "other" :
 226                            tok_argv[i].tokval == SMTPD_TOK_ERROR ? "error" :
 227                            "unknown");
 228             vstream_printf("Token value: %s\n", tok_argv[i].strval);
 229         }
 230     }
 231     vstring_free(vp);
 232     exit(0);
 233 }
 234
 235 #endif