curl/src/tool_cb_hdr.c

/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2011, Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at http://curl.haxx.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ***************************************************************************/
#include "setup.h"

#include <curl/curl.h>

#include "rawstr.h"

#define ENABLE_CURLX_PRINTF
/* use our own printf() functions */
#include "curlx.h"

#include "tool_cfgable.h"
#include "tool_msgs.h"
#include "tool_cb_hdr.h"

#include "memdebug.h" /* keep this as LAST include */

static char *parse_filename(const char *ptr, size_t len);

/*
** callback for CURLOPT_HEADERFUNCTION
*/

size_t tool_header_cb(void *ptr, size_t size, size_t nmemb, void *userdata)
{
  struct OutStruct *outs = userdata;
  const char *str = ptr;
  const size_t cb = size * nmemb;
  const char *end = (char*)ptr + cb;

  /*
   * Once that libcurl has called back tool_header_cb() the returned value
   * is checked against the amount that was intended to be written, if
   * it does not match then it fails with CURLE_WRITE_ERROR. So at this
   * point returning a value different from sz*nmemb indicates failure.
   */
  size_t failure = (size * nmemb) ? 0 : 1;

  if(!outs->config)
    return failure;

#ifdef DEBUGBUILD
  if((size * nmemb > (size_t)CURL_MAX_WRITE_SIZE) ||
     (size * nmemb > (size_t)CURL_MAX_HTTP_HEADER)) {
    warnf(outs->config, "Header data exceeds single call write limit!\n");
    return failure;
  }
#endif

  if(!outs->filename && (cb > 20) &&
    checkprefix("Content-disposition:", str)) {
    const char *p = str + 20;

    /* look for the 'filename=' parameter
       (encoded filenames (*=) are not supported) */
    for(;;) {
      char *filename;
      size_t len;

      while(*p && (p < end) && !ISALPHA(*p))
        p++;
      if(p > end - 9)
        break;

      if(memcmp(p, "filename=", 9)) {
        /* no match, find next parameter */
        while((p < end) && (*p != ';'))
          p++;
        continue;
      }
      p += 9;

      /* this expression below typecasts 'cb' only to avoid
         warning: signed and unsigned type in conditional expression
      */
      len = (ssize_t)cb - (p - str);
      filename = parse_filename(p, len);
      if(filename) {
        outs->filename = filename;
        outs->alloc_filename = TRUE;
        outs->s_isreg = TRUE;
        outs->fopened = FALSE;
        outs->stream = NULL;
        break;
      }
      else
        return failure;
    }
  }

  return cb;
}

/*
 * Copies a file name part and returns an ALLOCATED data buffer.
 */
static char *parse_filename(const char *ptr, size_t len)
{
  char *copy;
  char *p;
  char *q;
  char  stop = '\0';

  /* simple implementation of strndup() */
  copy = malloc(len+1);
  if(!copy)
    return NULL;
  memcpy(copy, ptr, len);
  copy[len] = '\0';

  p = copy;
  if(*p == '\'' || *p == '"') {
    /* store the starting quote */
    stop = *p;
    p++;
  }
  else
    stop = ';';

  /* if the filename contains a path, only use filename portion */
  q = strrchr(copy, '/');
  if(q) {
    p = q + 1;
    if(!*p) {
      Curl_safefree(copy);
      return NULL;
    }
  }

  /* If the filename contains a backslash, only use filename portion. The idea
     is that even systems that don't handle backslashes as path separators
     probably want the path removed for convenience. */
  q = strrchr(p, '\\');
  if(q) {
    p = q + 1;
    if(!*p) {
      Curl_safefree(copy);
      return NULL;
    }
  }

  /* scan for the end letter and stop there */
  q = p;
  while(*q) {
    if(q[1] && (q[0] == '\\'))
      q++;
    else if(q[0] == stop)
      break;
    q++;
  }
  *q = '\0';

  /* make sure the file name doesn't end in \r or \n */
  q = strchr(p, '\r');
  if(q)
    *q = '\0';

  q = strchr(p, '\n');
  if(q)
    *q = '\0';

  if(copy != p)
    memmove(copy, p, strlen(p) + 1);

  /* in case we built debug enabled, we allow an evironment variable
   * named CURL_TESTDIR to prefix the given file name to put it into a
   * specific directory
   */
#ifdef DEBUGBUILD
  {
    char *tdir = curlx_getenv("CURL_TESTDIR");
    if(tdir) {
      char buffer[512]; /* suitably large */
      snprintf(buffer, sizeof(buffer), "%s/%s", tdir, copy);
      Curl_safefree(copy);
      copy = strdup(buffer); /* clone the buffer, we don't use the libcurl
                                aprintf() or similar since we want to use the
                                same memory code as the "real" parse_filename
                                function */
      curl_free(tdir);
    }
  }
#endif

  return copy;
}