LibSSH2简单入门-exec、sftp
LibSSH2简单入门-exec、sftp
1、libssh2官方地址：libssh2
libssh2的官方文档和官方示例代码非常的棒，基本可以直接参考
官方文档：libssh2 docs
官方示例：libssh2 examples
2、推荐阅读两个示例，基本可以完成对libssh2的理解和使用了
2.1、ssh2_exec.c 通过libssh2在远端机器上执行指令，并获取指令的返回值
/* Copyright (C) The libssh2 project and its contributors.
*
* Sample showing how to use libssh2 to execute a command remotely.
*
* The sample code has fixed values for host name, user name, password
* and command to run.
*
* $ ./ssh2_exec 127.0.0.1 user password "uptime"
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include "libssh2_setup.h"
#include " );
/*****
* At this point, we could verify that 'check' tells us the key is
* fine or bail out.
*****/
}
else {
/* eeek, do cleanup here */
return 3;
}
libssh2_knownhost_free(nh);
if(strlen(password) != 0) {
/* 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,
pubkey, privkey,
password)) ==
LIBSSH2_ERROR_EAGAIN);
if(rc) {
fprintf(stderr, "Authentication by public key failed.\n");
goto shutdown;
}
}
#if 0
libssh2_trace(session, ~0);
#endif
/* Exec non-blocking on the remote host */
do {
channel = libssh2_channel_open_session(session);
if(channel ||
libssh2_session_last_error(session, NULL, NULL, 0) !=
LIBSSH2_ERROR_EAGAIN)
break;
waitsocket(sock, session);
} while(1);
if(!channel) {
fprintf(stderr, "Error\n");
exit(1);
}
while((rc = libssh2_channel_exec(channel, commandline)) == LIBSSH2_ERROR_EAGAIN) {
waitsocket(sock, session);
}
if(rc) {
fprintf(stderr, "exec error\n");
exit(1);
}
for(;;) {
ssize_t nread;
/* loop until we block */
do {
char buffer[0x4000];
nread = libssh2_channel_read(channel, buffer, sizeof(buffer));
if(nread > 0) {
ssize_t i;
bytecount += nread;
fprintf(stderr, "We read:\n");
for(i = 0; i < nread; ++i)
fputc(buffer[i], stderr);
fprintf(stderr, "\n");
}
else {
if(nread != LIBSSH2_ERROR_EAGAIN)
/* no need to output this for the EAGAIN case */
fprintf(stderr, "libssh2_channel_read returned %d\n",
(int)nread);
}
}
while(nread > 0);
/* this is due to blocking that would occur otherwise so we loop on
this condition */
if(nread == LIBSSH2_ERROR_EAGAIN) {
waitsocket(sock, session);
}
else
break;
}
exitcode = 127;
while((rc = libssh2_channel_close(channel)) == LIBSSH2_ERROR_EAGAIN)
waitsocket(sock, session);
if(rc == 0) {
exitcode = libssh2_channel_get_exit_status(channel);
libssh2_channel_get_exit_signal(channel, &exitsignal, NULL, NULL, NULL, NULL, NULL);
}
if(exitsignal)
fprintf(stderr, "\nGot signal: %s\n", exitsignal);
else
fprintf(stderr, "\nEXIT: %d bytecount: %d\n",
exitcode, (int)bytecount);
libssh2_channel_free(channel);
channel = NULL;
shutdown:
if(session) {
libssh2_session_disconnect(session, "Normal Shutdown");
libssh2_session_free(session);
}
if(sock != LIBSSH2_INVALID_SOCKET) {
shutdown(sock, 2);
#ifdef WIN32
closesocket(sock);
#else
close(sock);
#endif
}
fprintf(stderr, "all done\n");
libssh2_exit();
return 0;
}
2.2、sftp_write_nonblock.c 使用libssh2进行sftp将本端文件传输到远端机器上的功能
/* Copyright (C) The libssh2 project and its contributors.
*
* Sample showing how to do SFTP non-blocking write transfers.
*
* The sample code has default values for host name, user name, password
* and path to copy, but you can specify them on the command line like:
*
* $ ./sftp_write_nonblock 192.168.0.1 user password thisfile /tmp/storehere
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include "libssh2_setup.h"
#include 注：示例代码中的fingerprint可以不一定需要使用。