1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2019, 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 https://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 /* <DESC>
23 * Upload to SFTP, resuming a previously aborted transfer.
24 * </DESC>
25 */
26
27 #include <stdlib.h>
28 #include <stdio.h>
29 #include <curl/curl.h>
30
31 /* read data to upload */
readfunc(void * ptr,size_t size,size_t nmemb,void * stream)32 static size_t readfunc(void *ptr, size_t size, size_t nmemb, void *stream)
33 {
34 FILE *f = (FILE *)stream;
35 size_t n;
36
37 if(ferror(f))
38 return CURL_READFUNC_ABORT;
39
40 n = fread(ptr, size, nmemb, f) * size;
41
42 return n;
43 }
44
45 /*
46 * sftpGetRemoteFileSize returns the remote file size in byte; -1 on error
47 */
sftpGetRemoteFileSize(const char * i_remoteFile)48 static curl_off_t sftpGetRemoteFileSize(const char *i_remoteFile)
49 {
50 CURLcode result = CURLE_GOT_NOTHING;
51 curl_off_t remoteFileSizeByte = -1;
52 CURL *curlHandlePtr = NULL;
53
54 curlHandlePtr = curl_easy_init();
55 curl_easy_setopt(curlHandlePtr, CURLOPT_VERBOSE, 1L);
56
57 curl_easy_setopt(curlHandlePtr, CURLOPT_URL, i_remoteFile);
58 curl_easy_setopt(curlHandlePtr, CURLOPT_NOPROGRESS, 1);
59 curl_easy_setopt(curlHandlePtr, CURLOPT_NOBODY, 1);
60 curl_easy_setopt(curlHandlePtr, CURLOPT_HEADER, 1);
61 curl_easy_setopt(curlHandlePtr, CURLOPT_FILETIME, 1);
62
63 result = curl_easy_perform(curlHandlePtr);
64 if(CURLE_OK == result) {
65 result = curl_easy_getinfo(curlHandlePtr,
66 CURLINFO_CONTENT_LENGTH_DOWNLOAD_T,
67 &remoteFileSizeByte);
68 if(result)
69 return -1;
70 printf("filesize: %" CURL_FORMAT_CURL_OFF_T "\n", remoteFileSizeByte);
71 }
72 curl_easy_cleanup(curlHandlePtr);
73
74 return remoteFileSizeByte;
75 }
76
77
sftpResumeUpload(CURL * curlhandle,const char * remotepath,const char * localpath)78 static int sftpResumeUpload(CURL *curlhandle, const char *remotepath,
79 const char *localpath)
80 {
81 FILE *f = NULL;
82 CURLcode result = CURLE_GOT_NOTHING;
83
84 curl_off_t remoteFileSizeByte = sftpGetRemoteFileSize(remotepath);
85 if(-1 == remoteFileSizeByte) {
86 printf("Error reading the remote file size: unable to resume upload\n");
87 return -1;
88 }
89
90 f = fopen(localpath, "rb");
91 if(!f) {
92 perror(NULL);
93 return 0;
94 }
95
96 curl_easy_setopt(curlhandle, CURLOPT_UPLOAD, 1L);
97 curl_easy_setopt(curlhandle, CURLOPT_URL, remotepath);
98 curl_easy_setopt(curlhandle, CURLOPT_READFUNCTION, readfunc);
99 curl_easy_setopt(curlhandle, CURLOPT_READDATA, f);
100
101 #ifdef _WIN32
102 _fseeki64(f, remoteFileSizeByte, SEEK_SET);
103 #else
104 fseek(f, (long)remoteFileSizeByte, SEEK_SET);
105 #endif
106 curl_easy_setopt(curlhandle, CURLOPT_APPEND, 1L);
107 result = curl_easy_perform(curlhandle);
108
109 fclose(f);
110
111 if(result == CURLE_OK)
112 return 1;
113 else {
114 fprintf(stderr, "%s\n", curl_easy_strerror(result));
115 return 0;
116 }
117 }
118
main(void)119 int main(void)
120 {
121 const char *remote = "sftp://user:pass@example.com/path/filename";
122 const char *filename = "filename";
123 CURL *curlhandle = NULL;
124
125 curl_global_init(CURL_GLOBAL_ALL);
126 curlhandle = curl_easy_init();
127
128 if(!sftpResumeUpload(curlhandle, remote, filename)) {
129 printf("resumed upload using curl %s failed\n", curl_version());
130 }
131
132 curl_easy_cleanup(curlhandle);
133 curl_global_cleanup();
134
135 return 0;
136 }
137