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ssh2/example/sftp_RW_nonblock.c

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C
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/*
* Sample showing how to do SFTP transfers in a non-blocking manner.
*
* It will first download a given source file, store it locally and then
* upload the file again to a given destination file.
*
* Using the SFTP server running on 127.0.0.1
*/
#include "libssh2_config.h"
#include <libssh2.h>
#include <libssh2_sftp.h>
#ifdef HAVE_WINSOCK2_H
# include <winsock2.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
# include <sys/socket.h>
#endif
#ifdef HAVE_NETINET_IN_H
# include <netinet/in.h>
#endif
#ifdef HAVE_SYS_SELECT_H
# include <sys/select.h>
#endif
# ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_ARPA_INET_H
# include <arpa/inet.h>
#endif
#ifdef HAVE_SYS_TIME_H
# include <sys/time.h>
#endif
#include <sys/types.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <ctype.h>
#define STORAGE "/tmp/sftp-storage" /* this is the local file name this
example uses to store the downloaded
file in */
static int waitsocket(int socket_fd, LIBSSH2_SESSION *session)
{
struct timeval timeout;
int rc;
fd_set fd;
fd_set *writefd = NULL;
fd_set *readfd = NULL;
int dir;
timeout.tv_sec = 10;
timeout.tv_usec = 0;
FD_ZERO(&fd);
FD_SET(socket_fd, &fd);
/* now make sure we wait in the correct direction */
dir = libssh2_session_block_directions(session);
if(dir & LIBSSH2_SESSION_BLOCK_INBOUND)
readfd = &fd;
if(dir & LIBSSH2_SESSION_BLOCK_OUTBOUND)
writefd = &fd;
rc = select(socket_fd + 1, readfd, writefd, NULL, &timeout);
return rc;
}
int main(int argc, char *argv[])
{
int sock, i, auth_pw = 1;
struct sockaddr_in sin;
const char *fingerprint;
LIBSSH2_SESSION *session;
const char *username="username";
const char *password="password";
const char *sftppath="/tmp/TEST"; /* source path */
const char *dest="/tmp/TEST2"; /* destination path */
int rc;
LIBSSH2_SFTP *sftp_session;
LIBSSH2_SFTP_HANDLE *sftp_handle;
FILE *tempstorage;
char mem[1000];
struct timeval timeout;
fd_set fd;
#ifdef WIN32
WSADATA wsadata;
int err;
err = WSAStartup(MAKEWORD(2,0), &wsadata);
if (err != 0) {
fprintf(stderr, "WSAStartup failed with error: %d\n", err);
return 1;
}
#endif
rc = libssh2_init (0);
if (rc != 0) {
fprintf (stderr, "libssh2 initialization failed (%d)\n", rc);
return 1;
}
/* Ultra basic "connect to port 22 on localhost"
* The application is responsible for creating the socket establishing
* the connection
*/
sock = socket(AF_INET, SOCK_STREAM, 0);
sin.sin_family = AF_INET;
sin.sin_port = htons(22);
sin.sin_addr.s_addr = htonl(0x7F000001);
if (connect(sock, (struct sockaddr*)(&sin),
sizeof(struct sockaddr_in)) != 0) {
fprintf(stderr, "failed to connect!\n");
return -1;
}
/* Create a session instance
*/
session = libssh2_session_init();
if(!session)
return -1;
/* ... start it up. This will trade welcome banners, exchange keys,
* and setup crypto, compression, and MAC layers
*/
rc = libssh2_session_handshake(session, sock);
if(rc) {
fprintf(stderr, "Failure establishing SSH session: %d\n", rc);
return -1;
}
libssh2_session_set_blocking(session, 0);
/* At this point we havn't yet authenticated. The first thing to do
* is check the hostkey's fingerprint against our known hosts Your app
* may have it hard coded, may go to a file, may present it to the
* user, that's your call
*/
fingerprint = libssh2_hostkey_hash(session, LIBSSH2_HOSTKEY_HASH_SHA1);
fprintf(stderr, "Fingerprint: ");
for(i = 0; i < 20; i++) {
fprintf(stderr, "%02X ", (unsigned char)fingerprint[i]);
}
fprintf(stderr, "\n");
if(argc > 1) {
username = argv[1];
}
if(argc > 2) {
password = argv[2];
}
if(argc > 3) {
sftppath = argv[3];
}
if(argc > 4) {
dest = argv[4];
}
tempstorage = fopen(STORAGE, "wb");
if(!tempstorage) {
fprintf(stderr, "Can't open temp storage file %s\n", STORAGE);
goto shutdown;
}
if (auth_pw) {
/* We could authenticate via password */
while ((rc = libssh2_userauth_password(session, username, password))
== LIBSSH2_ERROR_EAGAIN);
if (rc) {
fprintf(stderr, "Authentication by password failed.\n");
goto shutdown;
}
} else {
/* Or by public key */
while ((rc =
libssh2_userauth_publickey_fromfile(session, username,
"/home/username/"
".ssh/id_rsa.pub",
"/home/username/"
".ssh/id_rsa",
password)) ==
LIBSSH2_ERROR_EAGAIN);
if (rc) {
fprintf(stderr, "\tAuthentication by public key failed\n");
goto shutdown;
}
}
do {
sftp_session = libssh2_sftp_init(session);
if(!sftp_session) {
if(libssh2_session_last_errno(session) ==
LIBSSH2_ERROR_EAGAIN) {
fprintf(stderr, "non-blocking init\n");
waitsocket(sock, session); /* now we wait */
}
else {
fprintf(stderr, "Unable to init SFTP session\n");
goto shutdown;
}
}
} while (!sftp_session);
/* Request a file via SFTP */
do {
sftp_handle = libssh2_sftp_open(sftp_session, sftppath,
LIBSSH2_FXF_READ, 0);
if (!sftp_handle) {
if (libssh2_session_last_errno(session) != LIBSSH2_ERROR_EAGAIN) {
fprintf(stderr, "Unable to open file with SFTP\n");
goto shutdown;
}
else {
fprintf(stderr, "non-blocking open\n");
waitsocket(sock, session); /* now we wait */
}
}
} while (!sftp_handle);
fprintf(stderr, "libssh2_sftp_open() is done, now receive data!\n");
do {
do {
/* read in a loop until we block */
rc = libssh2_sftp_read(sftp_handle, mem, sizeof(mem));
fprintf(stderr, "libssh2_sftp_read returned %d\n",
rc);
if(rc > 0) {
/* write to stderr */
write(2, mem, rc);
/* write to temporary storage area */
fwrite(mem, rc, 1, tempstorage);
}
} while (rc > 0);
if(rc != LIBSSH2_ERROR_EAGAIN) {
/* error or end of file */
break;
}
timeout.tv_sec = 10;
timeout.tv_usec = 0;
FD_ZERO(&fd);
FD_SET(sock, &fd);
/* wait for readable or writeable */
rc = select(sock+1, &fd, &fd, NULL, &timeout);
if(rc <= 0) {
/* negative is error
0 is timeout */
fprintf(stderr, "SFTP download timed out: %d\n", rc);
break;
}
} while (1);
libssh2_sftp_close(sftp_handle);
fclose(tempstorage);
tempstorage = fopen(STORAGE, "rb");
if(!tempstorage) {
/* weird, we can't read the file we just wrote to... */
fprintf(stderr, "can't open %s for reading\n", STORAGE);
goto shutdown;
}
/* we're done downloading, now reverse the process and upload the
temporarily stored data to the destination path */
sftp_handle =
libssh2_sftp_open(sftp_session, dest,
LIBSSH2_FXF_WRITE|LIBSSH2_FXF_CREAT,
LIBSSH2_SFTP_S_IRUSR|LIBSSH2_SFTP_S_IWUSR|
LIBSSH2_SFTP_S_IRGRP|LIBSSH2_SFTP_S_IROTH);
if(sftp_handle) {
size_t nread;
char *ptr;
do {
nread = fread(mem, 1, sizeof(mem), tempstorage);
if(nread <= 0) {
/* end of file */
break;
}
ptr = mem;
do {
/* write data in a loop until we block */
rc = libssh2_sftp_write(sftp_handle, ptr,
nread);
ptr += rc;
nread -= nread;
} while (rc >= 0);
if(rc != LIBSSH2_ERROR_EAGAIN) {
/* error or end of file */
break;
}
timeout.tv_sec = 10;
timeout.tv_usec = 0;
FD_ZERO(&fd);
FD_SET(sock, &fd);
/* wait for readable or writeable */
rc = select(sock+1, &fd, &fd, NULL, &timeout);
if(rc <= 0) {
/* negative is error
0 is timeout */
fprintf(stderr, "SFTP upload timed out: %d\n",
rc);
break;
}
} while (1);
fprintf(stderr, "SFTP upload done!\n");
}
else {
fprintf(stderr, "SFTP failed to open destination path: %s\n",
dest);
}
libssh2_sftp_shutdown(sftp_session);
shutdown:
libssh2_session_disconnect(session, "Normal Shutdown, Thank you for playing");
libssh2_session_free(session);
#ifdef WIN32
closesocket(sock);
#else
close(sock);
#endif
if (tempstorage)
fclose(tempstorage);
fprintf(stderr, "all done\n");
libssh2_exit();
return 0;
}
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