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libssh2/example/ssh2_echo.c
Viktor Szakats 2efdb6747a
tidy-up: example, tests continued 
- fix skip auth if `userauthlist` is NULL.
  Closes #836 (Reported-by: @sudipm-mukherjee on github)
- fix most silenced `checksrc` warnings.
- sync examples/tests code between each other.
  (output messages, error handling, declaration order, comments)
- stop including unnecessary headers.
- always deinitialize in case of error.
- drop some redundant variables.
- add error handling where missing.
- show more error codes.
- switch `perror()` to `fprintf()`.
- fix some `printf()`s to be `fprintf()`.
- formatting.

Closes #960
2023-04-14 11:07:53 +00:00

378 lines
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/*
* The code sends a 'cat' command, and then writes a lot of data to it only to
* check that reading the returned data sums up to the same amount.
*
* $ ./ssh2_echo 127.0.0.1 user password
*
*/
#include "libssh2_setup.h"
#include <libssh2.h>
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.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 <stdlib.h>
#include <ctype.h>
static const char *hostname = "127.0.0.1";
static const char *commandline = "cat";
static const char *username = "user";
static const char *password = "password";
static int waitsocket(libssh2_socket_t 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((int)(socket_fd + 1), readfd, writefd, NULL, &timeout);
return rc;
}
#define BUFSIZE 32000
int main(int argc, char *argv[])
{
uint32_t hostaddr;
libssh2_socket_t sock;
struct sockaddr_in sin;
const char *fingerprint;
int rc;
LIBSSH2_SESSION *session = NULL;
LIBSSH2_CHANNEL *channel;
int exitcode = 0;
char *exitsignal = (char *)"none";
size_t len;
LIBSSH2_KNOWNHOSTS *nh;
int type;
#ifdef WIN32
WSADATA wsadata;
rc = WSAStartup(MAKEWORD(2, 0), &wsadata);
if(rc) {
fprintf(stderr, "WSAStartup failed with error: %d\n", rc);
return 1;
}
#endif
if(argc > 1) {
hostname = argv[1]; /* must be ip address only */
}
if(argc > 2) {
username = argv[2];
}
if(argc > 3) {
password = argv[3];
}
rc = libssh2_init(0);
if(rc) {
fprintf(stderr, "libssh2 initialization failed (%d)\n", rc);
return 1;
}
hostaddr = inet_addr(hostname);
/* Ultra basic "connect to port 22 on localhost". Your code is
* responsible for creating the socket establishing the connection
*/
sock = socket(AF_INET, SOCK_STREAM, 0);
if(sock == LIBSSH2_INVALID_SOCKET) {
fprintf(stderr, "failed to create socket!\n");
goto shutdown;
}
sin.sin_family = AF_INET;
sin.sin_port = htons(22);
sin.sin_addr.s_addr = hostaddr;
if(connect(sock, (struct sockaddr*)(&sin), sizeof(struct sockaddr_in))) {
fprintf(stderr, "failed to connect!\n");
goto shutdown;
}
/* Create a session instance */
session = libssh2_session_init();
if(!session) {
fprintf(stderr, "Could not initialize SSH session!\n");
goto shutdown;
}
/* tell libssh2 we want it all done non-blocking */
libssh2_session_set_blocking(session, 0);
/* ... start it up. This will trade welcome banners, exchange keys,
* and setup crypto, compression, and MAC layers
*/
while((rc = libssh2_session_handshake(session, sock)) ==
LIBSSH2_ERROR_EAGAIN);
if(rc) {
fprintf(stderr, "Failure establishing SSH session: %d\n", rc);
goto shutdown;
}
nh = libssh2_knownhost_init(session);
if(!nh) {
/* eeek, do cleanup here */
return 2;
}
/* read all hosts from here */
libssh2_knownhost_readfile(nh, "known_hosts",
LIBSSH2_KNOWNHOST_FILE_OPENSSH);
/* store all known hosts to here */
libssh2_knownhost_writefile(nh, "dumpfile",
LIBSSH2_KNOWNHOST_FILE_OPENSSH);
fingerprint = libssh2_session_hostkey(session, &len, &type);
if(fingerprint) {
struct libssh2_knownhost *host;
int check = libssh2_knownhost_checkp(nh, hostname, 22,
fingerprint, len,
LIBSSH2_KNOWNHOST_TYPE_PLAIN|
LIBSSH2_KNOWNHOST_KEYENC_RAW,
&host);
fprintf(stderr, "Host check: %d, key: %s\n", check,
(check <= LIBSSH2_KNOWNHOST_CHECK_MISMATCH) ?
host->key : "<none>");
/*****
* 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");
exit(1);
}
}
libssh2_trace(session, LIBSSH2_TRACE_SOCKET);
/* 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);
}
else {
LIBSSH2_POLLFD *fds = NULL;
int running = 1;
ssize_t bufsize = BUFSIZE;
char buffer[BUFSIZE];
ssize_t totsize = 1500000;
ssize_t totwritten = 0;
ssize_t totread = 0;
int rereads = 0;
int rewrites = 0;
int i;
for(i = 0; i < BUFSIZE; i++)
buffer[i] = 'A';
fds = malloc(sizeof(LIBSSH2_POLLFD));
if(!fds) {
fprintf(stderr, "malloc failed\n");
exit(1);
}
fds[0].type = LIBSSH2_POLLFD_CHANNEL;
fds[0].fd.channel = channel;
fds[0].events = LIBSSH2_POLLFD_POLLIN | LIBSSH2_POLLFD_POLLOUT;
do {
int act = 0;
rc = libssh2_poll(fds, 1, 10);
if(rc < 1)
continue;
if(fds[0].revents & LIBSSH2_POLLFD_POLLIN) {
ssize_t n = libssh2_channel_read(channel,
buffer, sizeof(buffer));
act++;
if(n == LIBSSH2_ERROR_EAGAIN) {
rereads++;
fprintf(stderr, "will read again\n");
}
else if(n < 0) {
fprintf(stderr, "read failed\n");
exit(1);
}
else {
totread += n;
fprintf(stderr, "read %d bytes (%d in total)\n",
(int)n, (int)totread);
}
}
if(fds[0].revents & LIBSSH2_POLLFD_POLLOUT) {
act++;
if(totwritten < totsize) {
/* we have not written all data yet */
ssize_t left = totsize - totwritten;
ssize_t size = (left < bufsize) ? left : bufsize;
ssize_t n = libssh2_channel_write_ex(channel, 0,
buffer, size);
if(n == LIBSSH2_ERROR_EAGAIN) {
rewrites++;
fprintf(stderr, "will write again\n");
}
else if(n < 0) {
fprintf(stderr, "write failed\n");
exit(1);
}
else {
totwritten += n;
fprintf(stderr, "wrote %d bytes (%d in total)",
(int)n, (int)totwritten);
if(left >= bufsize && n != bufsize) {
fprintf(stderr, " PARTIAL");
}
fprintf(stderr, "\n");
}
}
else {
/* all data written, send EOF */
rc = libssh2_channel_send_eof(channel);
if(rc == LIBSSH2_ERROR_EAGAIN) {
fprintf(stderr, "will send eof again\n");
}
else if(rc < 0) {
fprintf(stderr, "send eof failed\n");
exit(1);
}
else {
fprintf(stderr, "sent eof\n");
/* we're done writing, stop listening for OUT events */
fds[0].events &= ~LIBSSH2_POLLFD_POLLOUT;
}
}
}
if(fds[0].revents & LIBSSH2_POLLFD_CHANNEL_CLOSED) {
if(!act) /* don't leave loop until we have read all data */
running = 0;
}
} while(running);
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);
libssh2_channel_free(channel);
channel = NULL;
fprintf(stderr, "\nrereads: %d rewrites: %d totwritten %d\n",
rereads, rewrites, (int)totwritten);
if(totwritten != totread) {
fprintf(stderr, "\n*** FAIL bytes written: %d bytes "
"read: %d ***\n", (int)totwritten, (int)totread);
exit(1);
}
}
shutdown:
if(session) {
libssh2_session_disconnect(session, "Normal Shutdown");
libssh2_session_free(session);
}
if(sock != LIBSSH2_INVALID_SOCKET) {
#ifdef WIN32
closesocket(sock);
#else
close(sock);
#endif
}
fprintf(stderr, "all done\n");
libssh2_exit();
return exitcode;
}
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