formdata.c

/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2008, 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.
 *
 * $Id$
 ***************************************************************************/

/*
  Debug the form generator stand-alone by compiling this source file with:

  gcc -DHAVE_CONFIG_H -I../ -g -D_FORM_DEBUG -DCURLDEBUG -o formdata \
    -I../include formdata.c strequal.c memdebug.c mprintf.c strerror.c

  (depending on circumstances you may need further externals added)

  run the 'formdata' executable the output should end with:
  All Tests seem to have worked ...
  and the following parts should be there:

Content-Disposition: form-data; name="simple_COPYCONTENTS"
value for simple COPYCONTENTS

Content-Disposition: form-data; name="COPYCONTENTS_+_CONTENTTYPE"
Content-Type: image/gif
value for COPYCONTENTS + CONTENTTYPE

Content-Disposition: form-data; name="PRNAME_+_NAMELENGTH_+_COPYNAME_+_CONTENTSLENGTH"
vlue for PTRNAME + NAMELENGTH + COPYNAME + CONTENTSLENGTH
(or you might see P^@RNAME and v^@lue at the start)

Content-Disposition: form-data; name="simple_PTRCONTENTS"
value for simple PTRCONTENTS

Content-Disposition: form-data; name="PTRCONTENTS_+_CONTENTSLENGTH"
vlue for PTRCONTENTS + CONTENTSLENGTH
(or you might see v^@lue at the start)

Content-Disposition: form-data; name="PTRCONTENTS_+_CONTENTSLENGTH_+_CONTENTTYPE"
Content-Type: application/octet-stream
vlue for PTRCONTENTS + CONTENTSLENGTH + CONTENTTYPE
(or you might see v^@lue at the start)

Content-Disposition: form-data; name="FILE1_+_CONTENTTYPE"; filename="formdata.h"
Content-Type: text/html
...

Content-Disposition: form-data; name="FILE1_+_FILE2"
Content-Type: multipart/mixed, boundary=curlz1s0dkticx49MV1KGcYP5cvfSsz
...
Content-Disposition: attachment; filename="formdata.h"
Content-Type: application/octet-stream
...
Content-Disposition: attachment; filename="Makefile.b32"
Content-Type: application/octet-stream
...

Content-Disposition: form-data; name="FILE1_+_FILE2_+_FILE3"
Content-Type: multipart/mixed, boundary=curlirkYPmPwu6FrJ1vJ1u1BmtIufh1
...
Content-Disposition: attachment; filename="formdata.h"
Content-Type: application/octet-stream
...
Content-Disposition: attachment; filename="Makefile.b32"
Content-Type: application/octet-stream
...
Content-Disposition: attachment; filename="formdata.h"
Content-Type: application/octet-stream
...


Content-Disposition: form-data; name="ARRAY: FILE1_+_FILE2_+_FILE3"
Content-Type: multipart/mixed, boundary=curlirkYPmPwu6FrJ1vJ1u1BmtIufh1
...
Content-Disposition: attachment; filename="formdata.h"
Content-Type: application/octet-stream
...
Content-Disposition: attachment; filename="Makefile.b32"
Content-Type: application/octet-stream
...
Content-Disposition: attachment; filename="formdata.h"
Content-Type: application/octet-stream
...

Content-Disposition: form-data; name="FILECONTENT"
...

 */

#include "setup.h"
#include <curl/curl.h>

/* Length of the random boundary string. */
#define BOUNDARY_LENGTH 40

#if !defined(CURL_DISABLE_HTTP) || defined(USE_SSLEAY)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <time.h>
#if defined(HAVE_LIBGEN_H) && defined(HAVE_BASENAME)
#include <libgen.h>
#endif
#include "urldata.h" /* for struct SessionHandle */
#include "easyif.h" /* for Curl_convert_... prototypes */
#include "formdata.h"
#include "strequal.h"
#include "memory.h"

#define _MPRINTF_REPLACE /* use our functions only */
#include <curl/mprintf.h>

/* The last #include file should be: */
#include "memdebug.h"

#endif  /* !defined(CURL_DISABLE_HTTP) || defined(USE_SSLEAY) */

#ifndef CURL_DISABLE_HTTP

#if defined(HAVE_BASENAME) && defined(NEED_BASENAME_PROTO)
/* This system has a basename() but no prototype for it! */
char *basename(char *path);
#endif

static size_t readfromfile(struct Form *form, char *buffer, size_t size);

/* What kind of Content-Type to use on un-specified files with unrecognized
   extensions. */
#define HTTPPOST_CONTENTTYPE_DEFAULT "application/octet-stream"

#define FORM_FILE_SEPARATOR ','
#define FORM_TYPE_SEPARATOR ';'

/***************************************************************************
 *
 * AddHttpPost()
 *
 * Adds a HttpPost structure to the list, if parent_post is given becomes
 * a subpost of parent_post instead of a direct list element.
 *
 * Returns newly allocated HttpPost on success and NULL if malloc failed.
 *
 ***************************************************************************/
static struct curl_httppost *
AddHttpPost(char *name, size_t namelength,
            char *value, size_t contentslength,
            char *buffer, size_t bufferlength,
            char *contenttype,
            long flags,
            struct curl_slist* contentHeader,
            char *showfilename, char *userp,
            struct curl_httppost *parent_post,
            struct curl_httppost **httppost,
            struct curl_httppost **last_post)
{
  struct curl_httppost *post;
  post = calloc(sizeof(struct curl_httppost), 1);
  if(post) {
    post->name = name;
    post->namelength = (long)(name?(namelength?namelength:strlen(name)):0);
    post->contents = value;
    post->contentslength = (long)contentslength;
    post->buffer = buffer;
    post->bufferlength = (long)bufferlength;
    post->contenttype = contenttype;
    post->contentheader = contentHeader;
    post->showfilename = showfilename;
    post->userp = userp,
    post->flags = flags;
  }
  else
    return NULL;

  if(parent_post) {
    /* now, point our 'more' to the original 'more' */
    post->more = parent_post->more;

    /* then move the original 'more' to point to ourselves */
    parent_post->more = post;
  }
  else {
    /* make the previous point to this */
    if(*last_post)
      (*last_post)->next = post;
    else
      (*httppost) = post;

    (*last_post) = post;
  }
  return post;
}

/***************************************************************************
 *
 * AddFormInfo()
 *
 * Adds a FormInfo structure to the list presented by parent_form_info.
 *
 * Returns newly allocated FormInfo on success and NULL if malloc failed/
 * parent_form_info is NULL.
 *
 ***************************************************************************/
static FormInfo * AddFormInfo(char *value,
                              char *contenttype,
                              FormInfo *parent_form_info)
{
  FormInfo *form_info;
  form_info = malloc(sizeof(FormInfo));
  if(form_info) {
    memset(form_info, 0, sizeof(FormInfo));
    if(value)
      form_info->value = value;
    if(contenttype)
      form_info->contenttype = contenttype;
    form_info->flags = HTTPPOST_FILENAME;
  }
  else
    return NULL;

  if(parent_form_info) {
    /* now, point our 'more' to the original 'more' */
    form_info->more = parent_form_info->more;

    /* then move the original 'more' to point to ourselves */
    parent_form_info->more = form_info;
  }
  else
    return NULL;

  return form_info;
}

/***************************************************************************
 *
 * ContentTypeForFilename()
 *
 * Provides content type for filename if one of the known types (else
 * (either the prevtype or the default is returned).
 *
 * Returns some valid contenttype for filename.
 *
 ***************************************************************************/
static const char * ContentTypeForFilename (const char *filename,
                                            const char *prevtype)
{
  const char *contenttype = NULL;
  unsigned int i;
  /*
   * No type was specified, we scan through a few well-known
   * extensions and pick the first we match!
   */
  struct ContentType {
    const char *extension;
    const char *type;
  };
  static const struct ContentType ctts[]={
    {".gif",  "image/gif"},
    {".jpg",  "image/jpeg"},
    {".jpeg", "image/jpeg"},
    {".txt",  "text/plain"},
    {".html", "text/html"}
  };

  if(prevtype)
    /* default to the previously set/used! */
    contenttype = prevtype;
  else
    contenttype = HTTPPOST_CONTENTTYPE_DEFAULT;

  if(filename) { /* in case a NULL was passed in */
    for(i=0; i<sizeof(ctts)/sizeof(ctts[0]); i++) {
      if(strlen(filename) >= strlen(ctts[i].extension)) {
        if(strequal(filename +
                    strlen(filename) - strlen(ctts[i].extension),
                    ctts[i].extension)) {
          contenttype = ctts[i].type;
          break;
        }
      }
    }
  }
  /* we have a contenttype by now */
  return contenttype;
}

/***************************************************************************
 *
 * memdup()
 *
 * Copies the 'source' data to a newly allocated buffer buffer (that is
 * returned). Uses buffer_length if not null, else uses strlen to determine
 * the length of the buffer to be copied
 *
 * Returns the new pointer or NULL on failure.
 *
 ***************************************************************************/
static char *memdup(const char *src, size_t buffer_length)
{
  size_t length;
  bool add = FALSE;
  char *buffer;

  if(buffer_length)
    length = buffer_length;
  else if(src) {
    length = strlen(src);
    add = TRUE;
  }
  else
    /* no length and a NULL src pointer! */
    return strdup("");

  buffer = malloc(length+add);
  if(!buffer)
    return NULL; /* fail */

  memcpy(buffer, src, length);

  /* if length unknown do null termination */
  if(add)
    buffer[length] = '\0';

  return buffer;
}

/***************************************************************************
 *
 * FormAdd()
 *
 * Stores a formpost parameter and builds the appropriate linked list.
 *
 * Has two principal functionalities: using files and byte arrays as
 * post parts. Byte arrays are either copied or just the pointer is stored
 * (as the user requests) while for files only the filename and not the
 * content is stored.
 *
 * While you may have only one byte array for each name, multiple filenames
 * are allowed (and because of this feature CURLFORM_END is needed after
 * using CURLFORM_FILE).
 *
 * Examples:
 *
 * Simple name/value pair with copied contents:
 * curl_formadd (&post, &last, CURLFORM_COPYNAME, "name",
 * CURLFORM_COPYCONTENTS, "value", CURLFORM_END);
 *
 * name/value pair where only the content pointer is remembered:
 * curl_formadd (&post, &last, CURLFORM_COPYNAME, "name",
 * CURLFORM_PTRCONTENTS, ptr, CURLFORM_CONTENTSLENGTH, 10, CURLFORM_END);
 * (if CURLFORM_CONTENTSLENGTH is missing strlen () is used)
 *
 * storing a filename (CONTENTTYPE is optional!):
 * curl_formadd (&post, &last, CURLFORM_COPYNAME, "name",
 * CURLFORM_FILE, "filename1", CURLFORM_CONTENTTYPE, "plain/text",
 * CURLFORM_END);
 *
 * storing multiple filenames:
 * curl_formadd (&post, &last, CURLFORM_COPYNAME, "name",
 * CURLFORM_FILE, "filename1", CURLFORM_FILE, "filename2", CURLFORM_END);
 *
 * Returns:
 * CURL_FORMADD_OK             on success
 * CURL_FORMADD_MEMORY         if the FormInfo allocation fails
 * CURL_FORMADD_OPTION_TWICE   if one option is given twice for one Form
 * CURL_FORMADD_NULL           if a null pointer was given for a char
 * CURL_FORMADD_MEMORY         if the allocation of a FormInfo struct failed
 * CURL_FORMADD_UNKNOWN_OPTION if an unknown option was used
 * CURL_FORMADD_INCOMPLETE     if the some FormInfo is not complete (or an error)
 * CURL_FORMADD_MEMORY         if a HttpPost struct cannot be allocated
 * CURL_FORMADD_MEMORY         if some allocation for string copying failed.
 * CURL_FORMADD_ILLEGAL_ARRAY  if an illegal option is used in an array
 *
 ***************************************************************************/

static
CURLFORMcode FormAdd(struct curl_httppost **httppost,
                     struct curl_httppost **last_post,
                     va_list params)
{
  FormInfo *first_form, *current_form, *form = NULL;
  CURLFORMcode return_value = CURL_FORMADD_OK;
  const char *prevtype = NULL;
  struct curl_httppost *post = NULL;
  CURLformoption option;
  struct curl_forms *forms = NULL;
  char *array_value=NULL; /* value read from an array */

  /* This is a state variable, that if TRUE means that we're parsing an
     array that we got passed to us. If FALSE we're parsing the input
     va_list arguments. */
  bool array_state = FALSE;

  /*
   * We need to allocate the first struct to fill in.
   */
  first_form = calloc(sizeof(struct FormInfo), 1);
  if(!first_form)
    return CURL_FORMADD_MEMORY;

  current_form = first_form;

  /*
   * Loop through all the options set. Break if we have an error to report.
   */
  while(return_value == CURL_FORMADD_OK) {

    /* first see if we have more parts of the array param */
    if( array_state ) {
      /* get the upcoming option from the given array */
      option = forms->option;
      array_value = (char *)forms->value;

      forms++; /* advance this to next entry */
      if(CURLFORM_END == option) {
        /* end of array state */
        array_state = FALSE;
        continue;
      }
    }
    else {
      /* This is not array-state, get next option */
      option = va_arg(params, CURLformoption);
      if(CURLFORM_END == option)
        break;
    }

    switch (option) {
    case CURLFORM_ARRAY:
      if(array_state)
        /* we don't support an array from within an array */
        return_value = CURL_FORMADD_ILLEGAL_ARRAY;
      else {
        forms = va_arg(params, struct curl_forms *);
        if(forms)
          array_state = TRUE;
        else
          return_value = CURL_FORMADD_NULL;
      }
      break;

      /*
       * Set the Name property.
       */
    case CURLFORM_PTRNAME:
#ifdef CURL_DOES_CONVERSIONS
      /* treat CURLFORM_PTR like CURLFORM_COPYNAME so we'll
         have safe memory for the eventual conversion */
#else
      current_form->flags |= HTTPPOST_PTRNAME; /* fall through */
#endif
    case CURLFORM_COPYNAME:
      if(current_form->name)
        return_value = CURL_FORMADD_OPTION_TWICE;
      else {
        char *name = array_state?
          array_value:va_arg(params, char *);
        if(name)
          current_form->name = name; /* store for the moment */
        else
          return_value = CURL_FORMADD_NULL;
      }
      break;
    case CURLFORM_NAMELENGTH:
      if(current_form->namelength)
        return_value = CURL_FORMADD_OPTION_TWICE;
      else
        current_form->namelength =
          array_state?(size_t)array_value:(size_t)va_arg(params, long);
      break;

      /*
       * Set the contents property.
       */
    case CURLFORM_PTRCONTENTS:
      current_form->flags |= HTTPPOST_PTRCONTENTS; /* fall through */
    case CURLFORM_COPYCONTENTS:
      if(current_form->value)
        return_value = CURL_FORMADD_OPTION_TWICE;
      else {
        char *value =
          array_state?array_value:va_arg(params, char *);
        if(value)
          current_form->value = value; /* store for the moment */
        else
          return_value = CURL_FORMADD_NULL;
      }
      break;
    case CURLFORM_CONTENTSLENGTH:
      if(current_form->contentslength)
        return_value = CURL_FORMADD_OPTION_TWICE;
      else
        current_form->contentslength =
          array_state?(size_t)array_value:(size_t)va_arg(params, long);
      break;

      /* Get contents from a given file name */
    case CURLFORM_FILECONTENT:
      if(current_form->flags != 0)
        return_value = CURL_FORMADD_OPTION_TWICE;
      else {
        const char *filename = array_state?
          array_value:va_arg(params, char *);
        if(filename) {
          current_form->value = strdup(filename);
          if(!current_form->value)
            return_value = CURL_FORMADD_MEMORY;
          else {
            current_form->flags |= HTTPPOST_READFILE;
            current_form->value_alloc = TRUE;
          }
        }
        else
          return_value = CURL_FORMADD_NULL;
      }
      break;

      /* We upload a file */
    case CURLFORM_FILE:
      {
        const char *filename = array_state?array_value:
          va_arg(params, char *);

        if(current_form->value) {
          if(current_form->flags & HTTPPOST_FILENAME) {
            if(filename) {
              if((current_form = AddFormInfo(strdup(filename),
                                              NULL, current_form)) == NULL)
                return_value = CURL_FORMADD_MEMORY;
            }
            else
              return_value = CURL_FORMADD_NULL;
          }
          else
            return_value = CURL_FORMADD_OPTION_TWICE;
        }
        else {
          if(filename) {
            current_form->value = strdup(filename);
            if(!current_form->value)
              return_value = CURL_FORMADD_MEMORY;
            else {
              current_form->flags |= HTTPPOST_FILENAME;
              current_form->value_alloc = TRUE;
            }
          }
          else
            return_value = CURL_FORMADD_NULL;
        }
        break;
      }

    case CURLFORM_BUFFER:
      {
        const char *filename = array_state?array_value:
          va_arg(params, char *);

        if(current_form->value) {
          if(current_form->flags & HTTPPOST_BUFFER) {
            if(filename) {
              if((current_form = AddFormInfo(strdup(filename),
                                              NULL, current_form)) == NULL)
                return_value = CURL_FORMADD_MEMORY;
            }
            else
              return_value = CURL_FORMADD_NULL;
          }
          else
            return_value = CURL_FORMADD_OPTION_TWICE;
        }
        else {
          if(filename) {
            current_form->value = strdup(filename);
            if(!current_form->value)
              return_value = CURL_FORMADD_MEMORY;
          }
          else
            return_value = CURL_FORMADD_NULL;
          current_form->flags |= HTTPPOST_BUFFER;
        }
        break;
      }

    case CURLFORM_BUFFERPTR:
      current_form->flags |= HTTPPOST_PTRBUFFER;
      if(current_form->buffer)
        return_value = CURL_FORMADD_OPTION_TWICE;
      else {
        char *buffer =
          array_state?array_value:va_arg(params, char *);
        if(buffer)
          current_form->buffer = buffer; /* store for the moment */
        else
          return_value = CURL_FORMADD_NULL;
      }
      break;

    case CURLFORM_BUFFERLENGTH:
      if(current_form->bufferlength)
        return_value = CURL_FORMADD_OPTION_TWICE;
      else
        current_form->bufferlength =
          array_state?(size_t)array_value:(size_t)va_arg(params, long);
      break;

    case CURLFORM_STREAM:
      current_form->flags |= HTTPPOST_CALLBACK;
      if(current_form->userp)
        return_value = CURL_FORMADD_OPTION_TWICE;
      else {
        char *userp =
          array_state?array_value:va_arg(params, char *);
        if(userp) {
          current_form->userp = userp;
          current_form->value = userp; /* this isn't strictly true but we
                                          derive a value from this later on
                                          and we need this non-NULL to be
                                          accepted as a fine form part */
        }
        else
          return_value = CURL_FORMADD_NULL;
      }
      break;

    case CURLFORM_CONTENTTYPE:
      {
        const char *contenttype =
          array_state?array_value:va_arg(params, char *);
        if(current_form->contenttype) {
          if(current_form->flags & HTTPPOST_FILENAME) {
            if(contenttype) {
              if((current_form = AddFormInfo(NULL,
                                              strdup(contenttype),
                                              current_form)) == NULL)
                return_value = CURL_FORMADD_MEMORY;
            }
            else
              return_value = CURL_FORMADD_NULL;
          }
          else
            return_value = CURL_FORMADD_OPTION_TWICE;
        }
        else {
          if(contenttype) {
            current_form->contenttype = strdup(contenttype);
            if(!current_form->contenttype)
              return_value = CURL_FORMADD_MEMORY;
            else
              current_form->contenttype_alloc = TRUE;
          }
          else
            return_value = CURL_FORMADD_NULL;
        }
        break;
      }
    case CURLFORM_CONTENTHEADER:
      {
        /* this "cast increases required alignment of target type" but
           we consider it OK anyway */
        struct curl_slist* list = array_state?
          (struct curl_slist*)array_value:
          va_arg(params, struct curl_slist*);

        if( current_form->contentheader )
          return_value = CURL_FORMADD_OPTION_TWICE;
        else
          current_form->contentheader = list;

        break;
      }
    case CURLFORM_FILENAME:
      {
        const char *filename = array_state?array_value:
          va_arg(params, char *);
        if( current_form->showfilename )
          return_value = CURL_FORMADD_OPTION_TWICE;
        else {
          current_form->showfilename = strdup(filename);
          if(!current_form->showfilename)
            return_value = CURL_FORMADD_MEMORY;
          else
            current_form->showfilename_alloc = TRUE;
        }
        break;
      }
    default:
      return_value = CURL_FORMADD_UNKNOWN_OPTION;
    }
  }

  if(CURL_FORMADD_OK == return_value) {
    /* go through the list, check for completeness and if everything is
     * alright add the HttpPost item otherwise set return_value accordingly */

    post = NULL;
    for(form = first_form;
        form != NULL;
        form = form->more) {
      if( ((!form->name || !form->value) && !post) ||
          ( (form->contentslength) &&
            (form->flags & HTTPPOST_FILENAME) ) ||
          ( (form->flags & HTTPPOST_FILENAME) &&
            (form->flags & HTTPPOST_PTRCONTENTS) ) ||

          ( (!form->buffer) &&
            (form->flags & HTTPPOST_BUFFER) &&
            (form->flags & HTTPPOST_PTRBUFFER) ) ||

          ( (form->flags & HTTPPOST_READFILE) &&
            (form->flags & HTTPPOST_PTRCONTENTS) )
        ) {
        return_value = CURL_FORMADD_INCOMPLETE;
        break;
      }
      else {
        if( ((form->flags & HTTPPOST_FILENAME) ||
              (form->flags & HTTPPOST_BUFFER)) &&
             !form->contenttype ) {
          /* our contenttype is missing */
          form->contenttype
            = strdup(ContentTypeForFilename(form->value, prevtype));
          if(!form->contenttype) {
            return_value = CURL_FORMADD_MEMORY;
            break;
          }
          form->contenttype_alloc = TRUE;
        }
        if( !(form->flags & HTTPPOST_PTRNAME) &&
             (form == first_form) ) {
          /* Note that there's small risk that form->name is NULL here if the
             app passed in a bad combo, so we better check for that first. */
          if(form->name)
            /* copy name (without strdup; possibly contains null characters) */
            form->name = memdup(form->name, form->namelength);
          if(!form->name) {
            return_value = CURL_FORMADD_MEMORY;
            break;
          }
          form->name_alloc = TRUE;
        }
        if( !(form->flags & (HTTPPOST_FILENAME | HTTPPOST_READFILE |
                             HTTPPOST_PTRCONTENTS | HTTPPOST_PTRBUFFER |
                             HTTPPOST_CALLBACK)) ) {
          /* copy value (without strdup; possibly contains null characters) */
          form->value = memdup(form->value, form->contentslength);
          if(!form->value) {
            return_value = CURL_FORMADD_MEMORY;
            break;
          }
          form->value_alloc = TRUE;
        }
        post = AddHttpPost(form->name, form->namelength,
                           form->value, form->contentslength,
                           form->buffer, form->bufferlength,
                           form->contenttype, form->flags,
                           form->contentheader, form->showfilename,
                           form->userp,
                           post, httppost,
                           last_post);

        if(!post) {
          return_value = CURL_FORMADD_MEMORY;
          break;
        }

        if(form->contenttype)
          prevtype = form->contenttype;
      }
    }
  }

  if(return_value) {
    /* we return on error, free possibly allocated fields */
    if(!form)
      form = current_form;
    if(form) {
      if(form->name_alloc)
        free(form->name);
      if(form->value_alloc)
        free(form->value);
      if(form->contenttype_alloc)
        free(form->contenttype);
      if(form->showfilename_alloc)
        free(form->showfilename);
    }
  }

  /* always delete the allocated memory before returning */
  form = first_form;
  while(form != NULL) {
    FormInfo *delete_form;

    delete_form = form;
    form = form->more;
    free (delete_form);
  }

  return return_value;
}

/*
 * curl_formadd() is a public API to add a section to the multipart formpost.
 */

CURLFORMcode curl_formadd(struct curl_httppost **httppost,
                          struct curl_httppost **last_post,
                          ...)
{
  va_list arg;
  CURLFORMcode result;
  va_start(arg, last_post);
  result = FormAdd(httppost, last_post, arg);
  va_end(arg);
  return result;
}

/*
 * AddFormData() adds a chunk of data to the FormData linked list.
 *
 * size is incremented by the chunk length, unless it is NULL
 */
static CURLcode AddFormData(struct FormData **formp,
                            enum formtype type,
                            const void *line,
                            size_t length,
                            curl_off_t *size)
{
  struct FormData *newform = malloc(sizeof(struct FormData));
  if(!newform)
    return CURLE_OUT_OF_MEMORY;
  newform->next = NULL;

  if(type <= FORM_CONTENT) {
    /* we make it easier for plain strings: */
    if(!length)
      length = strlen((char *)line);

    newform->line = malloc(length+1);
    if(!newform->line) {
      free(newform);
      return CURLE_OUT_OF_MEMORY;
    }
    memcpy(newform->line, line, length);
    newform->length = length;
    newform->line[length]=0; /* zero terminate for easier debugging */
  }
  else
    /* For callbacks and files we don't have any actual data so we just keep a
       pointer to whatever this points to */
    newform->line = (char *)line;

  newform->type = type;

  if(*formp) {
    (*formp)->next = newform;
    *formp = newform;
  }
  else
    *formp = newform;

  if(size) {
    if(type != FORM_FILE)
      /* for static content as well as callback data we add the size given
         as input argument */
      *size += length;
    else {
      /* Since this is a file to be uploaded here, add the size of the actual
         file */
      if(!strequal("-", newform->line)) {
        struct_stat file;
        if(!stat(newform->line, &file)) {
          *size += file.st_size;
        }
      }
    }
  }
  return CURLE_OK;
}

/*
 * AddFormDataf() adds printf()-style formatted data to the formdata chain.
 */

static CURLcode AddFormDataf(struct FormData **formp,
                             curl_off_t *size,
                             const char *fmt, ...)
{
  char s[4096];
  va_list ap;
  va_start(ap, fmt);
  vsnprintf(s, sizeof(s), fmt, ap);
  va_end(ap);

  return AddFormData(formp, FORM_DATA, s, 0, size);
}

/*
 * Curl_formclean() is used from http.c, this cleans a built FormData linked
 * list
 */
void Curl_formclean(struct FormData **form_ptr)
{
  struct FormData *next, *form;

  form = *form_ptr;
  if(!form)
    return;

  do {
    next=form->next;  /* the following form line */
    if(form->type <= FORM_CONTENT)
      free(form->line); /* free the line */
    free(form);       /* free the struct */

  } while((form = next) != NULL); /* continue */

  *form_ptr = NULL;
}

#ifdef CURL_DOES_CONVERSIONS
/*
 * Curl_formcovert() is used from http.c, this converts any
   form items that need to be sent in the network encoding.
   Returns CURLE_OK on success.
 */
CURLcode Curl_formconvert(struct SessionHandle *data, struct FormData *form)
{
  struct FormData *next;
  CURLcode rc;

  if(!form)
    return CURLE_OK;

  if(!data)
    return CURLE_BAD_FUNCTION_ARGUMENT;

  do {
    next=form->next;  /* the following form line */
    if(form->type == FORM_DATA) {
      rc = Curl_convert_to_network(data, form->line, form->length);
      /* Curl_convert_to_network calls failf if unsuccessful */
      if(rc != CURLE_OK)
        return rc;
    }
  } while((form = next) != NULL); /* continue */
  return CURLE_OK;
}
#endif /* CURL_DOES_CONVERSIONS */

/*
 * curl_formget()
 * Serialize a curl_httppost struct.
 * Returns 0 on success.
 */
int curl_formget(struct curl_httppost *form, void *arg,
                 curl_formget_callback append)
{
  CURLcode rc;
  curl_off_t size;
  struct FormData *data, *ptr;

  rc = Curl_getFormData(&data, form, NULL, &size);
  if(rc != CURLE_OK)
    return (int)rc;

  for (ptr = data; ptr; ptr = ptr->next) {
    if(ptr->type == FORM_FILE) {
      char buffer[8192];
      size_t nread;
      struct Form temp;

      Curl_FormInit(&temp, ptr);

      do {
        nread = readfromfile(&temp, buffer, sizeof(buffer));
        if((nread == (size_t) -1) || (nread != append(arg, buffer, nread))) {
          if(temp.fp) {
            fclose(temp.fp);
          }
          Curl_formclean(&data);
          return -1;
        }
      } while(nread == sizeof(buffer));
    } else {