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PowerPMAC driver suggested improvements #108

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23666e5
Improve character array handling ind remove magic numbers from the Po…
ajgdls Sep 11, 2023
898b70a
Updated buffer name to read_buffer_.
ajgdls Oct 16, 2023
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108 changes: 76 additions & 32 deletions pmacApp/powerPmacAsynPortSrc/sshDriver.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,15 @@
#include <osiUnistd.h>
#include <osiSock.h>
#include <poll.h>
#include <stdlib.h>

#define SSH_PORT 22
#define SSH_NOT_CONNECTED 0
#define SSH_CONNECTED 1
#define SSH_ERROR_TIMEOUT_MS 100

#define PPMAC_MAX_CHAR_LENGTH 7168
#define PPMAC_DOUBLE_MAX_LENGTH 2*PPMAC_MAX_CHAR_LENGTH

/*
* Uncomment the DEBUG define and recompile for lots of
Expand Down Expand Up @@ -95,10 +104,18 @@ SSHDriver::SSHDriver(const char *host)
// Initialize internal SSH parameters
auth_pw_ = 0;
got_ = 0;
connected_ = 0;
// Username and password currently set to empty strings
strcpy(username_, "");
strcpy(password_, "");
connected_ = SSH_NOT_CONNECTED;
// Initialise username and password
username_ = NULL;
password_ = NULL;

// Allocate memory required for the write method buffers
write_input_ = (char *)malloc(PPMAC_MAX_CHAR_LENGTH);
read_buffer_ = (char *)malloc(PPMAC_DOUBLE_MAX_LENGTH);
write_expected_echo_ = (char *)malloc(PPMAC_DOUBLE_MAX_LENGTH);

// Allocate the memory required to store the host address
host_ = (char *)malloc(strlen(host));
// Store the host address
strcpy(host_, host);

Expand All @@ -121,6 +138,12 @@ SSHDriverStatus SSHDriver::setUsername(const char *username)
static const char *functionName = "SSHDriver::setUsername";
debugPrint("%s : Method called\n", functionName);

// Allocate the memory for the username
if (username_){
free(username_);
}
username_ = (char *)malloc(strlen(username));

// Store the username
strcpy(username_, username);

Expand All @@ -140,6 +163,12 @@ SSHDriverStatus SSHDriver::setPassword(const char *password)
static const char *functionName = "SSHDriver::setPassword";
debugPrint("%s : Method called\n", functionName);

// Allocate the memory for the password
if (password_){
free(password_);
}
password_ = (char *)malloc(strlen(password));

// Store the password
strcpy(password_, password);

Expand Down Expand Up @@ -190,7 +219,7 @@ SSHDriverStatus SSHDriver::connectSSH()
sock_ = socket(AF_INET, SOCK_STREAM, 0);

sin_.sin_family = AF_INET;
sin_.sin_port = htons(22);
sin_.sin_port = htons(SSH_PORT);
sin_.sin_addr.s_addr = hostaddr;
if (connect(sock_, (struct sockaddr*)(&sin_), sizeof(struct sockaddr_in)) != 0){
debugPrint("%s : socket failed to connect!\n", functionName);
Expand All @@ -216,7 +245,7 @@ SSHDriverStatus SSHDriver::connectSSH()
}

// Here we now have a connection that will need to be closed
connected_ = 1;
connected_ = SSH_CONNECTED;

// At this point the connection hasn't yet authenticated. The first thing to do
// is check the hostkey's fingerprint against the known hosts.
Expand Down Expand Up @@ -280,7 +309,7 @@ SSHDriverStatus SSHDriver::connectSSH()
// Poll the underlying socket for bytes once connection established
// Do not read or write using libssh2 until the socket has received
// bytes from the server. These first bytes will contain the welcome
// message and then it is safe to proceed with reading and writing
// message and then it is safe to proceed with reading and writing
// through the established connection.
const char numfds = 1;
struct pollfd pfds[numfds];
Expand Down Expand Up @@ -360,11 +389,10 @@ SSHDriverStatus SSHDriver::setBlocking(int blocking)
*/
SSHDriverStatus SSHDriver::flush()
{
char buff[2048];
static const char *functionName = "SSHDriver::flush";
debugPrint("%s : Method called\n", functionName);

if (connected_ == 0){
if (connected_ == SSH_NOT_CONNECTED){
debugPrint("%s : Not connected\n", functionName);
return SSHDriverError;
}
Expand All @@ -376,7 +404,7 @@ SSHDriverStatus SSHDriver::flush()
return SSHDriverError;
}
// Read out any remaining bytes from t he channel
rc = libssh2_channel_read(channel_, buff, 2048);
rc = libssh2_channel_read(channel_, read_buffer_, PPMAC_DOUBLE_MAX_LENGTH);
if (rc > 0){
debugPrint("Flushed %d bytes\n", rc);
}
Expand Down Expand Up @@ -406,29 +434,33 @@ SSHDriverStatus SSHDriver::setErrorChecking(bool error_check)
*/
SSHDriverStatus SSHDriver::write(const char *buffer, size_t bufferSize, size_t *bytesWritten, int timeout)
{
char input[2048];
static const char *functionName = "SSHDriver::write";
debugPrint("%s : Method called\n", functionName);
*bytesWritten = 0;

if (connected_ == 0){
if (connected_ == SSH_NOT_CONNECTED){
debugPrint("%s : Not connected\n", functionName);
return SSHDriverError;
}

if (bufferSize > PPMAC_MAX_CHAR_LENGTH){
debugPrint("%s : write request exceeds the maximum buffer size\n", functionName);
return SSHDriverError;
}

timeval stime;
timeval ctime;
gettimeofday(&stime, NULL);
long mtimeout = (stime.tv_usec / 1000) + timeout;
long tnow = 0;

strncpy(input, buffer, bufferSize);
input[bufferSize] = 0;
strncpy(write_input_, buffer, bufferSize);
write_input_[bufferSize] = 0;
flush();
LogComPrint("LogCom sshDriver Writing %02lu bytes => ", (unsigned long)bufferSize);
LogComStrPrintEscapedNL(buffer, bufferSize);

int rc = libssh2_channel_write(channel_, input, bufferSize);
int rc = libssh2_channel_write(channel_, write_input_, bufferSize);
if (rc > 0){
debugPrint("%s : %d bytes written\n", functionName, rc);
*bytesWritten = rc;
Expand All @@ -439,31 +471,31 @@ SSHDriverStatus SSHDriver::write(const char *buffer, size_t bufferSize, size_t *
}

// Now we need to read back the same numer of bytes, to remove the written string from the buffer
// Each of these buffers must be twice that of the input buffer to allow for the PowerPMAC responding
// with a \r\n for every \n that is written by the request
int bytesToRead = *bytesWritten;
int bytes = 0;
char buff[512];
rc = 0;
int crCount = 0;

// Count the number of \n characters sent
// Build the expected ECHO string
char expected_response[512];
memset(expected_response, 0, 512);
memset(write_expected_echo_, 0, PPMAC_DOUBLE_MAX_LENGTH);
int expected_index = 0;
for (int index = 0; index < (int)*bytesWritten; index++){
if (buffer[index] == '\n'){
// CR, need to read back 1 extra character
crCount++;
expected_response[expected_index] = '\r';
write_expected_echo_[expected_index] = '\r';
expected_index++;
}
expected_response[expected_index] = buffer[index];
write_expected_echo_[expected_index] = buffer[index];
expected_index++;
}
bytesToRead += crCount;
int matched = 0;
while ((matched == 0) && (tnow < mtimeout)){
rc = libssh2_channel_read(channel_, &buff[bytes], bytesToRead);
rc = libssh2_channel_read(channel_, &read_buffer_[bytes], bytesToRead);
if (rc > 0){
bytes+=rc;
bytesToRead-=rc;
Expand All @@ -472,7 +504,7 @@ SSHDriverStatus SSHDriver::write(const char *buffer, size_t bufferSize, size_t *
if (bytes >= expected_index){
matched = 1;
for (int mid = 1; mid <= expected_index; mid++){
if (buff[bytes-mid] != expected_response[expected_index-mid]){
if (read_buffer_[bytes-mid] != write_expected_echo_[expected_index-mid]){
matched = 0;
}
}
Expand All @@ -486,32 +518,32 @@ SSHDriverStatus SSHDriver::write(const char *buffer, size_t bufferSize, size_t *
}

if (error_checking_){
if (buff[0] == '\r' && input[0] != '\r' && expected_index > 2){
if (read_buffer_[0] == '\r' && write_input_[0] != '\r' && expected_index > 2){
caught_errors_++;
debugPrint("Caught communication error\n");
debugPrint("Matched status: %d\n", matched);
debugPrint("Input string: ");
for (int index=0; index <= expected_index; index++){
debugPrint("[%d] ", input[index]);
debugPrint("[%d] ", write_input_[index]);
}
debugPrint("\n");
debugPrint("Expected response: ");
for (int index=0; index <= expected_index; index++){
debugPrint("[%d] ", expected_response[index]);
debugPrint("[%d] ", write_expected_echo_[index]);
}
debugPrint("\n");
debugPrint("Actual response: ");
for (int index=0; index <= expected_index; index++){
debugPrint("[%d] ", buff[index]);
debugPrint("[%d] ", read_buffer_[index]);
}
debugPrint("\n");
}
}

buff[bytes] = '\0';
read_buffer_[bytes] = '\0';

LogComPrint("LogCom sshDriver Echoed %02d bytes => ", bytes);
LogComStrPrintEscapedNL(buff, bytes);
LogComStrPrintEscapedNL(read_buffer_, bytes);


gettimeofday(&ctime, NULL);
Expand Down Expand Up @@ -546,7 +578,7 @@ SSHDriverStatus SSHDriver::read(char *buffer, size_t bufferSize, size_t *bytesRe
debugPrint("%s : Read terminator %d ", functionName, readTerm);
debugStrPrintEscapedNL(&ch, sizeof(ch));

if (connected_ == 0){
if (connected_ == SSH_NOT_CONNECTED){
debugPrint("%s : Not connected\n", functionName);
return SSHDriverError;
}
Expand Down Expand Up @@ -602,7 +634,7 @@ SSHDriverStatus SSHDriver::read(char *buffer, size_t bufferSize, size_t *bytesRe
}

if (error_checking_){
if ((mtimeout - tnow) < 100){
if ((mtimeout - tnow) < SSH_ERROR_TIMEOUT_MS){
debugPrint("Delay in read response: %ld ms\n", (timeout - (mtimeout - tnow)));
debugPrint("Input buffer: %s\n", buffer);
caught_delays_++;
Expand Down Expand Up @@ -681,8 +713,8 @@ SSHDriverStatus SSHDriver::disconnectSSH()
static const char *functionName = "SSHDriver::disconnect";
debugPrint("%s : Method called\n", functionName);

if (connected_ == 1){
connected_ = 0;
if (connected_ == SSH_CONNECTED){
connected_ = SSH_NOT_CONNECTED;
libssh2_session_disconnect(session_, "Normal Shutdown");
libssh2_session_free(session_);

Expand All @@ -704,6 +736,18 @@ SSHDriver::~SSHDriver()
{
static const char *functionName = "SSHDriver::~SSHDriver";
debugPrint("%s : Method called\n", functionName);

free(write_input_);
free(read_buffer_);
free(write_expected_echo_);

free(host_);
if (username_){
free(username_);
}
if (password_){
free(password_);
}
}

SSHDriverStatus SSHDriver::report(FILE *fp)
Expand Down
11 changes: 8 additions & 3 deletions pmacApp/powerPmacAsynPortSrc/sshDriver.h
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Original file line number Diff line number Diff line change
Expand Up @@ -69,11 +69,16 @@ class SSHDriver {
struct sockaddr_in sin_;
LIBSSH2_SESSION *session_;
LIBSSH2_CHANNEL *channel_;
char host_[256];
char username_[256];
char password_[256];
char *host_;
char *username_;
char *password_;
off_t got_;

// Memory blocks used when writing to the PowerPMAC
char *write_input_;
char *read_buffer_;
char *write_expected_echo_;

SSHDriverStatus setBlocking(int blocking);

bool error_checking_;
Expand Down