/*************************************************************************** * _ _ ____ _ * 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.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. * ***************************************************************************/ /* <DESC> * Upload to SFTP, resuming a previously aborted transfer. * </DESC> */ #include <stdlib.h> #include <stdio.h> #include <curl/curl.h> /* read data to upload */ static size_t readfunc(char *ptr, size_t size, size_t nmemb, void *stream) { FILE *f = (FILE *)stream; size_t n; if(ferror(f)) return CURL_READFUNC_ABORT; n = fread(ptr, size, nmemb, f) * size; return n; } /* * sftpGetRemoteFileSize returns the remote file size in byte; -1 on error */ static curl_off_t sftpGetRemoteFileSize(const char *i_remoteFile) { CURLcode result = CURLE_GOT_NOTHING; curl_off_t remoteFileSizeByte = -1; CURL *curlHandlePtr = curl_easy_init(); curl_easy_setopt(curlHandlePtr, CURLOPT_VERBOSE, 1L); curl_easy_setopt(curlHandlePtr, CURLOPT_URL, i_remoteFile); curl_easy_setopt(curlHandlePtr, CURLOPT_NOPROGRESS, 1); curl_easy_setopt(curlHandlePtr, CURLOPT_NOBODY, 1); curl_easy_setopt(curlHandlePtr, CURLOPT_HEADER, 1); curl_easy_setopt(curlHandlePtr, CURLOPT_FILETIME, 1); result = curl_easy_perform(curlHandlePtr); if(CURLE_OK == result) { result = curl_easy_getinfo(curlHandlePtr, CURLINFO_CONTENT_LENGTH_DOWNLOAD_T, &remoteFileSizeByte); if(result) return -1; printf("filesize: %" CURL_FORMAT_CURL_OFF_T "\n", remoteFileSizeByte); } curl_easy_cleanup(curlHandlePtr); return remoteFileSizeByte; } static int sftpResumeUpload(CURL *curlhandle, const char *remotepath, const char *localpath) { FILE *f = NULL; CURLcode result = CURLE_GOT_NOTHING; curl_off_t remoteFileSizeByte = sftpGetRemoteFileSize(remotepath); if(-1 == remoteFileSizeByte) { printf("Error reading the remote file size: unable to resume upload\n"); return -1; } f = fopen(localpath, "rb"); if(!f) { perror(NULL); return 0; } curl_easy_setopt(curlhandle, CURLOPT_UPLOAD, 1L); curl_easy_setopt(curlhandle, CURLOPT_URL, remotepath); curl_easy_setopt(curlhandle, CURLOPT_READFUNCTION, readfunc); curl_easy_setopt(curlhandle, CURLOPT_READDATA, f); #ifdef _WIN32 _fseeki64(f, remoteFileSizeByte, SEEK_SET); #else fseek(f, (long)remoteFileSizeByte, SEEK_SET); #endif curl_easy_setopt(curlhandle, CURLOPT_APPEND, 1L); result = curl_easy_perform(curlhandle); fclose(f); if(result == CURLE_OK) return 1; else { fprintf(stderr, "%s\n", curl_easy_strerror(result)); return 0; } } int main(void) { const char *remote = "sftp://user:pass@example.com/path/filename"; const char *filename = "filename"; CURL *curlhandle = NULL; curl_global_init(CURL_GLOBAL_ALL); curlhandle = curl_easy_init(); if(!sftpResumeUpload(curlhandle, remote, filename)) { printf("resumed upload using curl %s failed\n", curl_version()); } curl_easy_cleanup(curlhandle); curl_global_cleanup(); return 0; }