1/***************************************************************************
2 *                                  _   _ ____  _
3 *  Project                     ___| | | |  _ \| |
4 *                             / __| | | | |_) | |
5 *                            | (__| |_| |  _ <| |___
6 *                             \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2011, Daniel Stenberg, <daniel@haxx.se>, et al.
9 *
10 * This software is licensed as described in the file COPYING, which
11 * you should have received as part of this distribution. The terms
12 * are also available at http://curl.haxx.se/docs/copyright.html.
13 *
14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15 * copies of the Software, and permit persons to whom the Software is
16 * furnished to do so, under the terms of the COPYING file.
17 *
18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19 * KIND, either express or implied.
20 *
21 ***************************************************************************/
22#include "setup.h"
23
24#include <curl/curl.h>
25
26#define ENABLE_CURLX_PRINTF
27/* use our own printf() functions */
28#include "curlx.h"
29
30#include "tool_cfgable.h"
31#include "tool_msgs.h"
32#include "tool_cb_wrt.h"
33
34#include "memdebug.h" /* keep this as LAST include */
35
36/*
37** callback for CURLOPT_WRITEFUNCTION
38*/
39
40size_t tool_write_cb(void *buffer, size_t sz, size_t nmemb, void *userdata)
41{
42  size_t rc;
43  struct OutStruct *outs = userdata;
44  struct Configurable *config = outs->config;
45
46  /*
47   * Once that libcurl has called back tool_write_cb() the returned value
48   * is checked against the amount that was intended to be written, if
49   * it does not match then it fails with CURLE_WRITE_ERROR. So at this
50   * point returning a value different from sz*nmemb indicates failure.
51   */
52  const size_t failure = (sz * nmemb) ? 0 : 1;
53
54  if(!config)
55    return failure;
56
57#ifdef DEBUGBUILD
58  if(config->include_headers) {
59    if(sz * nmemb > (size_t)CURL_MAX_HTTP_HEADER) {
60      warnf(config, "Header data size exceeds single call write limit!\n");
61      return failure;
62    }
63  }
64  else {
65    if(sz * nmemb > (size_t)CURL_MAX_WRITE_SIZE) {
66      warnf(config, "Data size exceeds single call write limit!\n");
67      return failure;
68    }
69  }
70
71  {
72    /* Some internal congruency checks on received OutStruct */
73    bool check_fails = FALSE;
74    if(outs->filename) {
75      /* regular file */
76      if(!*outs->filename)
77        check_fails = TRUE;
78      if(!outs->s_isreg)
79        check_fails = TRUE;
80      if(outs->fopened && !outs->stream)
81        check_fails = TRUE;
82      if(!outs->fopened && outs->stream)
83        check_fails = TRUE;
84      if(!outs->fopened && outs->bytes)
85        check_fails = TRUE;
86    }
87    else {
88      /* standard stream */
89      if(!outs->stream || outs->s_isreg || outs->fopened)
90        check_fails = TRUE;
91      if(outs->alloc_filename || outs->init)
92        check_fails = TRUE;
93    }
94    if(check_fails) {
95      warnf(config, "Invalid output struct data for write callback\n");
96      return failure;
97    }
98  }
99#endif
100
101  if(!outs->stream) {
102    FILE *file;
103
104    if(!outs->filename || !*outs->filename) {
105      warnf(config, "Remote filename has no length!\n");
106      return failure;
107    }
108
109    if(config->content_disposition) {
110      /* don't overwrite existing files */
111      file = fopen(outs->filename, "rb");
112      if(file) {
113        fclose(file);
114        warnf(config, "Refusing to overwrite %s: %s\n", outs->filename,
115              strerror(EEXIST));
116        return failure;
117      }
118    }
119
120    /* open file for writing */
121    file = fopen(outs->filename, "wb");
122    if(!file) {
123      warnf(config, "Failed to create the file %s: %s\n", outs->filename,
124            strerror(errno));
125      return failure;
126    }
127    outs->s_isreg = TRUE;
128    outs->fopened = TRUE;
129    outs->stream = file;
130    outs->bytes = 0;
131    outs->init = 0;
132  }
133
134  rc = fwrite(buffer, sz, nmemb, outs->stream);
135
136  if((sz * nmemb) == rc)
137    /* we added this amount of data to the output */
138    outs->bytes += (sz * nmemb);
139
140  if(config->readbusy) {
141    config->readbusy = FALSE;
142    curl_easy_pause(config->easy, CURLPAUSE_CONT);
143  }
144
145  if(config->nobuffer) {
146    /* output buffering disabled */
147    int res = fflush(outs->stream);
148    if(res)
149      return failure;
150  }
151
152  return rc;
153}
154
155