curl/src/tool_cb_hdr.c

/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2020, 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 https://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 "tool_setup.h"

#include "strcase.h"

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

#include "tool_cfgable.h"
#include "tool_doswin.h"
#include "tool_msgs.h"
#include "tool_cb_hdr.h"
#include "tool_cb_wrt.h"
#include "tool_operate.h"

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

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

#ifdef WIN32
#define BOLD
#define BOLDOFF
#else
#define BOLD "\x1b[1m"
/* Switch off bold by setting "all attributes off" since the explicit
   bold-off code (21) isn't supported everywhere - like in the mac
   Terminal. */
#define BOLDOFF "\x1b[0m"
#endif

/*
** callback for CURLOPT_HEADERFUNCTION
*/

size_t tool_header_cb(char *ptr, size_t size, size_t nmemb, void *userdata)
{
  struct per_transfer *per = userdata;
  struct HdrCbData *hdrcbdata = &per->hdrcbdata;
  struct OutStruct *outs = &per->outs;
  struct OutStruct *heads = &per->heads;
  struct OutStruct *etag_save = &per->etag_save;
  const char *str = ptr;
  const size_t cb = size * nmemb;
  const char *end = (char *)ptr + cb;
  long protocol = 0;

  /*
   * 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(!per->config)
    return failure;

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

  /*
   * Write header data when curl option --dump-header (-D) is given.
   */

  if(per->config->headerfile && heads->stream) {
    size_t rc = fwrite(ptr, size, nmemb, heads->stream);
    if(rc != cb)
      return rc;
    /* flush the stream to send off what we got earlier */
    (void)fflush(heads->stream);
  }

  /*
   * Write etag to file when --etag-save option is given.
   * etag string that we want is enveloped in double quotes
   */
  if(per->config->etag_save_file && etag_save->stream) {
    /* match only header that start with etag (case insensitive) */
    if(curl_strnequal(str, "etag:", 5)) {
      char *etag_h = NULL;
      char *first = NULL;
      char *last = NULL;
      size_t etag_length = 0;

      etag_h = ptr;
      /* point to first occurrence of double quote */
      first = memchr(etag_h, '\"', cb);

      /*
       * if server side messed with the etag header and doesn't include
       * double quotes around the etag, kindly exit with a warning
       */

      if(!first) {
        warnf(per->config->global,
              "\nReceived header etag is missing double quote/s\n");
        return 1;
      }
      else {
        /* discard first double quote */
        first++;
      }

      /* point to last occurrence of double quote */
      last = memchr(first, '\"', cb);

      if(!last) {
        warnf(per->config->global,
              "\nReceived header etag is missing double quote/s\n");
        return 1;
      }

      /* get length of desired etag */
      etag_length = (size_t)last - (size_t)first;

      fwrite(first, size, etag_length, etag_save->stream);
      /* terminate with new line */
      fputc('\n', etag_save->stream);
    }

    (void)fflush(etag_save->stream);
  }

  /*
   * This callback sets the filename where output shall be written when
   * curl options --remote-name (-O) and --remote-header-name (-J) have
   * been simultaneously given and additionally server returns an HTTP
   * Content-Disposition header specifying a filename property.
   */

  curl_easy_getinfo(per->curl, CURLINFO_PROTOCOL, &protocol);
  if(hdrcbdata->honor_cd_filename &&
     (cb > 20) && checkprefix("Content-disposition:", str) &&
     (protocol & (CURLPROTO_HTTPS|CURLPROTO_HTTP))) {
    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) {
        if(outs->stream) {
          int rc;
          /* already opened and possibly written to */
          if(outs->fopened)
            fclose(outs->stream);
          outs->stream = NULL;

          /* rename the initial file name to the new file name */
          rc = rename(outs->filename, filename);
          if(rc != 0) {
            warnf(per->config->global, "Failed to rename %s -> %s: %s\n",
                  outs->filename, filename, strerror(errno));
          }
          if(outs->alloc_filename)
            Curl_safefree(outs->filename);
          if(rc != 0) {
            free(filename);
            return failure;
          }
        }
        outs->is_cd_filename = TRUE;
        outs->s_isreg = TRUE;
        outs->fopened = FALSE;
        outs->filename = filename;
        outs->alloc_filename = TRUE;
        hdrcbdata->honor_cd_filename = FALSE; /* done now! */
        if(!tool_create_output_file(outs, per->config))
          return failure;
      }
      break;
    }
    if(!outs->stream && !tool_create_output_file(outs, per->config))
      return failure;
  }

  if(hdrcbdata->config->show_headers &&
    (protocol &
     (CURLPROTO_HTTP|CURLPROTO_HTTPS|CURLPROTO_RTSP|CURLPROTO_FILE))) {
    /* bold headers only for selected protocols */
    char *value = NULL;

    if(!outs->stream && !tool_create_output_file(outs, per->config))
      return failure;

    if(hdrcbdata->global->isatty && hdrcbdata->global->styled_output)
      value = memchr(ptr, ':', cb);
    if(value) {
      size_t namelen = value - ptr;
      fprintf(outs->stream, BOLD "%.*s" BOLDOFF ":", namelen, ptr);
      fwrite(&value[1], cb - namelen - 1, 1, outs->stream);
    }
    else
      /* not "handled", just show it */
      fwrite(ptr, cb, 1, outs->stream);
  }
  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 = ';';

  /* scan for the end letter and stop there */
  q = strchr(p, stop);
  if(q)
    *q = '\0';

  /* if the filename contains a path, only use filename portion */
  q = strrchr(p, '/');
  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;
    }
  }

  /* 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);

#if defined(MSDOS) || defined(WIN32)
  {
    char *sanitized;
    SANITIZEcode sc = sanitize_file_name(&sanitized, copy, 0);
    Curl_safefree(copy);
    if(sc)
      return NULL;
    copy = sanitized;
  }
#endif /* MSDOS || WIN32 */

  /* in case we built debug enabled, we allow an environment 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 */
      msnprintf(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;
}