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 = curl_easy_init();
53
54 curl_easy_setopt(curlHandlePtr, CURLOPT_VERBOSE, 1L);
55
56 curl_easy_setopt(curlHandlePtr, CURLOPT_URL, i_remoteFile);
57 curl_easy_setopt(curlHandlePtr, CURLOPT_NOPROGRESS, 1);
58 curl_easy_setopt(curlHandlePtr, CURLOPT_NOBODY, 1);
59 curl_easy_setopt(curlHandlePtr, CURLOPT_HEADER, 1);
60 curl_easy_setopt(curlHandlePtr, CURLOPT_FILETIME, 1);
61
62 result = curl_easy_perform(curlHandlePtr);
63 if(CURLE_OK == result) {
64 result = curl_easy_getinfo(curlHandlePtr,
65 CURLINFO_CONTENT_LENGTH_DOWNLOAD_T,
66 &remoteFileSizeByte);
67 if(result)
68 return -1;
69 printf("filesize: %" CURL_FORMAT_CURL_OFF_T "\n", remoteFileSizeByte);
70 }
71 curl_easy_cleanup(curlHandlePtr);
72
73 return remoteFileSizeByte;
74 }
75
76
sftpResumeUpload(CURL * curlhandle,const char * remotepath,const char * localpath)77 static int sftpResumeUpload(CURL *curlhandle, const char *remotepath,
78 const char *localpath)
79 {
80 FILE *f = NULL;
81 CURLcode result = CURLE_GOT_NOTHING;
82
83 curl_off_t remoteFileSizeByte = sftpGetRemoteFileSize(remotepath);
84 if(-1 == remoteFileSizeByte) {
85 printf("Error reading the remote file size: unable to resume upload\n");
86 return -1;
87 }
88
89 f = fopen(localpath, "rb");
90 if(!f) {
91 perror(NULL);
92 return 0;
93 }
94
95 curl_easy_setopt(curlhandle, CURLOPT_UPLOAD, 1L);
96 curl_easy_setopt(curlhandle, CURLOPT_URL, remotepath);
97 curl_easy_setopt(curlhandle, CURLOPT_READFUNCTION, readfunc);
98 curl_easy_setopt(curlhandle, CURLOPT_READDATA, f);
99
100 #ifdef _WIN32
101 _fseeki64(f, remoteFileSizeByte, SEEK_SET);
102 #else
103 fseek(f, (long)remoteFileSizeByte, SEEK_SET);
104 #endif
105 curl_easy_setopt(curlhandle, CURLOPT_APPEND, 1L);
106 result = curl_easy_perform(curlhandle);
107
108 fclose(f);
109
110 if(result == CURLE_OK)
111 return 1;
112 else {
113 fprintf(stderr, "%s\n", curl_easy_strerror(result));
114 return 0;
115 }
116 }
117
main(void)118 int main(void)
119 {
120 const char *remote = "sftp://user:pass@example.com/path/filename";
121 const char *filename = "filename";
122 CURL *curlhandle = NULL;
123
124 curl_global_init(CURL_GLOBAL_ALL);
125 curlhandle = curl_easy_init();
126
127 if(!sftpResumeUpload(curlhandle, remote, filename)) {
128 printf("resumed upload using curl %s failed\n", curl_version());
129 }
130
131 curl_easy_cleanup(curlhandle);
132 curl_global_cleanup();
133
134 return 0;
135 }
136