libexec/ftp-proxy/getline.c

   1 /*      $OpenBSD: getline.c,v 1.15 2003/06/28 01:04:57 deraadt Exp $ */
   2 /*      $DragonFly: src/libexec/ftp-proxy/getline.c,v 1.2 2005/02/24 15:38:09 joerg Exp $ */
   3
   4 /*
   5  * Copyright (c) 1985, 1988 Regents of the University of California.
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  *
  32  *  @(#)ftpcmd.y    5.24 (Berkeley) 2/25/91
  33  */
  34
  35 #include <sys/types.h>
  36 #include <sys/socket.h>
  37
  38 #include <netinet/in.h>
  39 #include <arpa/telnet.h>
  40
  41 #include <errno.h>
  42 #include <stdlib.h>
  43 #include <stdio.h>
  44 #include <string.h>
  45 #include <sysexits.h>
  46 #include <syslog.h>
  47 #include <unistd.h>
  48
  49 #include "util.h"
  50
  51 int             refill_buffer(struct csiob *iobp);
  52
  53 /*
  54  * Refill the io buffer if we KNOW that data is available
  55  *
  56  * Returns 1 if any new data was obtained, 0 otherwise.
  57  */
  58
  59 int
  60 refill_buffer(struct csiob *iobp)
  61 {
  62         int rqlen, rlen;
  63
  64         if (!(iobp->data_available))
  65                 return(0);
  66
  67         if (iobp->got_eof)
  68                 return(0);
  69
  70         /*
  71          * The buffer has been entirely consumed if next_byte == io_buffer_len.
  72          * Otherwise, there is some still-to-be-used data in io_buffer.
  73          * Shuffle it to the start of the buffer.
  74          * Note that next_byte will never exceed io_buffer_len.
  75          * Also, note that we MUST use bcopy because the two regions could
  76          * overlap (memcpy isn't defined to work properly with overlapping
  77          * regions).
  78          */
  79         if (iobp->next_byte < iobp->io_buffer_len) {
  80                 int dst_ix = 0;
  81                 int src_ix = iobp->next_byte;
  82                 int amount = iobp->io_buffer_len - iobp->next_byte;
  83
  84                 bcopy(&iobp->io_buffer[src_ix], &iobp->io_buffer[dst_ix],
  85                     amount);
  86                 iobp->io_buffer_len = amount;
  87         } else if (iobp->next_byte == iobp->io_buffer_len)
  88                 iobp->io_buffer_len = 0;
  89         else {
  90                 syslog(LOG_ERR, "next_byte(%d) > io_buffer_len(%d)",
  91                     iobp->next_byte, iobp->io_buffer_len);
  92                 exit(EX_OSERR);
  93         }
  94
  95         iobp->next_byte = 0;
  96
  97         /* don't do tiny reads, grow first if we need to */
  98         rqlen = iobp->io_buffer_size - iobp->io_buffer_len;
  99         if (rqlen <= 128) {
 100                 unsigned char *tmp;
 101
 102                 iobp->io_buffer_size += 128;
 103                 tmp = realloc(iobp->io_buffer, iobp->io_buffer_size);
 104                 if (tmp == NULL) {
 105                         syslog(LOG_INFO, "Insufficient memory");
 106                         exit(EX_UNAVAILABLE);
 107                 }
 108                 iobp->io_buffer = tmp;
 109                 rqlen = iobp->io_buffer_size - iobp->io_buffer_len;
 110         }
 111
 112         /*
 113          * Always leave an unused byte at the end of the buffer
 114          * because the debug output uses that byte from time to time
 115          * to ensure that something that is being printed is \0 terminated.
 116          */
 117         rqlen -= 1;
 118
 119  doread:
 120         rlen = read(iobp->fd, &iobp->io_buffer[iobp->io_buffer_len], rqlen);
 121         iobp->data_available = 0;
 122         switch (rlen) {
 123         case -1:
 124                 if (errno == EAGAIN || errno == EINTR)
 125                         goto doread;
 126                 if (errno != ECONNRESET) {
 127                         syslog(LOG_INFO, "read() failed on socket from %s (%m)",
 128                             iobp->who);
 129                         exit(EX_DATAERR);
 130                 }
 131                 /* fall through to EOF case */
 132         case 0:
 133                 iobp->got_eof = 1;
 134                 return(0);
 135                 break;
 136         default:
 137                 iobp->io_buffer_len += rlen;
 138                 break;
 139         }
 140         return(1);
 141 }
 142
 143 /*
 144  * telnet_getline - a hacked up version of fgets to ignore TELNET escape codes.
 145  *
 146  * This code is derived from the getline routine found in the UC Berkeley
 147  * ftpd code.
 148  *
 149  */
 150
 151 int
 152 telnet_getline(struct csiob *iobp, struct csiob *telnet_passthrough)
 153 {
 154         unsigned char ch;
 155         int ix;
 156         unsigned char tbuf[100];
 157
 158         iobp->line_buffer[0] = '\0';
 159
 160         /*
 161          * If the buffer is empty then refill it right away.
 162          */
 163         if (iobp->next_byte == iobp->io_buffer_len)
 164                 if (!refill_buffer(iobp))
 165                         return(0);
 166
 167         /*
 168          * Is there a telnet command in the buffer?
 169          */
 170         ch = iobp->io_buffer[iobp->next_byte];
 171         if (ch == IAC) {
 172                 /*
 173                  * Yes - buffer must have at least three bytes in it
 174                  */
 175                 if (iobp->io_buffer_len - iobp->next_byte < 3) {
 176                         if (!refill_buffer(iobp))
 177                                 return(0);
 178                         if (iobp->io_buffer_len - iobp->next_byte < 3)
 179                                 return(0);
 180                 }
 181
 182                 iobp->next_byte++;
 183                 ch = iobp->io_buffer[iobp->next_byte++];
 184
 185                 switch (ch) {
 186                 case WILL:
 187                 case WONT:
 188                 case DO:
 189                 case DONT:
 190                         tbuf[0] = IAC;
 191                         tbuf[1] = ch;
 192                         tbuf[2] = iobp->io_buffer[iobp->next_byte++];
 193                         (void)send(telnet_passthrough->fd, tbuf, 3,
 194                             telnet_passthrough->send_oob_flags);
 195                         break;
 196                 case IAC:
 197                         break;
 198                 default:
 199                         break;
 200                 }
 201                 return(1);
 202         } else {
 203                 int clen;
 204
 205                 /*
 206                  * Is there a newline in the buffer?
 207                  */
 208                 for (ix = iobp->next_byte; ix < iobp->io_buffer_len;
 209                     ix += 1) {
 210                         if (iobp->io_buffer[ix] == '\n')
 211                                 break;
 212                         if (iobp->io_buffer[ix] == '\0') {
 213                                 syslog(LOG_INFO,
 214                                     "got NUL byte from %s - bye!",
 215                                     iobp->who);
 216                                 exit(EX_DATAERR);
 217                         }
 218                 }
 219
 220                 if (ix == iobp->io_buffer_len) {
 221                         if (!refill_buffer(iobp))
 222                                 return(0);
 223                         /*
 224                          * Empty line returned
 225                          * will try again soon!
 226                          */
 227                         return(1);
 228                 }
 229
 230                 /*
 231                  * Expand the line buffer if it isn't big enough.  We
 232                  * use a fudge factor of 5 rather than trying to
 233                  * figure out exactly how to account for the '\0 \r\n' and
 234                  * such.  The correct fudge factor is 0, 1 or 2 but
 235                  * anything higher also works. We also grow it by a
 236                  * bunch to avoid having to do this often. Yes this is
 237                  * nasty.
 238                  */
 239                 if (ix - iobp->next_byte > iobp->line_buffer_size - 5) {
 240                         unsigned char *tmp;
 241
 242                         iobp->line_buffer_size = 256 + ix - iobp->next_byte;
 243                         tmp = realloc(iobp->line_buffer,
 244                             iobp->line_buffer_size);
 245                         if (tmp == NULL) {
 246                                 syslog(LOG_INFO, "Insufficient memory");
 247                                 exit(EX_UNAVAILABLE);
 248                         }
 249                         iobp->line_buffer = tmp;
 250                 }
 251
 252                 /* +1 is for the newline */
 253                 clen = (ix+1) - iobp->next_byte;
 254                 memcpy(iobp->line_buffer, &iobp->io_buffer[iobp->next_byte],
 255                     clen);
 256                 iobp->next_byte += clen;
 257                 iobp->line_buffer[clen] = '\0';
 258                 return(1);
 259         }
 260 }