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ftp.c
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ftp.c
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#include "ftp.h"
#include "network.h"
#include "printRoutines.h"
#include <strings.h>
unsigned int sfd; // Control Connection fd
int main (int argc, char *argv[])
{
char line[MAX_LINE]; // stores terminal commands
char *command, *parameter;
int c;
if (argc < 2 || argc > 3) {
fprintf (stderr, "Usage: %s <host> <port>\n", argv[0]);
fprintf (stderr, " <host> The address of the ftp server.\n");
fprintf (stderr, " <port> Optional: Specifies the port the client should initiate connection on.\n");
return -1;
}
const char *port = argc == 3 ? argv[2] : DEFAULT_PORT;
sfd = create_connection (argv[1], port);
if (sfd < 0)
exit (EXIT_FAILURE);
char buffer[BUF_SIZE];
memset (buffer, 0, BUF_SIZE);
if (read_response (buffer) <= 0)
exit (EXIT_FAILURE);
while (1) {
// show prompt, but only if input comes from a terminal
if (isatty (STDIN_FILENO))
printf ("> ");
// break loop if EOF
if (!fgets (line, sizeof (line), stdin))
break;
// line could not be read entirely
if (!strchr (line, '\n')) {
// read to the end of the lline
while ((c = fgetc (stdin)) != EOF && c != '\n')
;
if (c == '\n') {
printErrorCommmandTooLong (stdout);
continue;
}
}
command = strtok (line, " \t\n\f\r\v");
if (!command)
continue; // ignore blank lines;
// get parameters if provided
parameter = strtok (NULL, "\n\r");
int scode = execute_command (command, parameter);
if (scode < 0) {
cleanup();
break;
}
}
return 0;
}
int execute_command (const char *command, const char *parameter)
{
if (strcasecmp (command, "quit") == 0) {
if (!check_argc (parameter, 0))
return printErrorInvalidParameter (stdout, parameter);
return quit_cmd (NULL);
}
else if (strcasecmp (command, "user") == 0) {
if (!check_argc (parameter, 1))
return printErrorInvalidParameter (stdout, parameter);
return login_cmd ("user", parameter, NULL);
}
else if (strcasecmp (command, "pass") == 0) {
if (!check_argc (parameter, 1))
return printErrorInvalidParameter (stdout, parameter);
return login_cmd ("pass", parameter, NULL);
}
else if (strcasecmp (command, "get") == 0) {
if (!check_argc (parameter, 1))
return printErrorInvalidParameter (stdout, parameter);
return get_cmd (parameter, NULL);
}
else if (strcasecmp (command, "features") == 0) {
if (!check_argc (parameter, 0))
return printErrorInvalidParameter (stdout, parameter);
return rand_cmd ("feat", NULL, NULL);
}
else if (strcasecmp (command, "cd") == 0) {
if (!check_argc (parameter, 1))
return printErrorInvalidParameter (stdout, parameter);
return rand_cmd ("cwd", parameter, NULL);
}
else if (strcasecmp (command, "nlist") == 0) {
if (!check_argc (parameter, 0) && !check_argc (parameter, 1))
return printErrorInvalidParameter (stdout, parameter);
return nlst_cmd (parameter, NULL);
}
else if (strcasecmp (command, "pwd") == 0) {
if (!check_argc (parameter, 0))
return printErrorInvalidParameter (stdout, parameter);
return rand_cmd ("pwd", NULL, NULL);
}
else if (strcasecmp (command, "put") == 0) {
if (!check_argc (parameter, 1))
return printErrorInvalidParameter (stdout, parameter);
return put_cmd (parameter, NULL);
}
else if (strcasecmp (command, "delete") == 0) {
if (!check_argc (parameter, 1))
return printErrorInvalidParameter (stdout, parameter);
return rand_cmd ("dele", parameter, NULL);
}
else {
return printErrorInvalidCommand (stdout, command);
}
return 0;
}
int login_cmd (const char *cmd, const char *param, char *response)
{
int length;
char buffer[BUF_SIZE];
char *res_buf = response == NULL ? buffer : response;
length = rand_cmd (cmd, param, res_buf);
return length < 0 ? -1 : bin_type (res_buf);
}
int rand_cmd (const char *cmd, const char *param, char *response)
{
char buffer[BUF_SIZE];
char *res_buff = response == NULL ? buffer : response;
memset (res_buff, 0, BUF_SIZE);
if (param != NULL) {
snprintf (res_buff, BUF_SIZE, "%s %s", cmd, param);
}
else {
snprintf (res_buff, BUF_SIZE, "%s", cmd);
}
ssize_t length = send_msg (res_buff);
return length < 0 ? -1 : read_response (res_buff);
}
int pasv_cmd (char *response)
{
char buffer[BUF_SIZE];
u_int32_t a, h1, h2, h3, h4, p1, p2;
char t[256];
int data_fd = -1;
char *res_buf = response == NULL ? buffer : response;
memset (res_buf, 0, BUF_SIZE);
snprintf (res_buf, BUF_SIZE, "%s", "pasv");
ssize_t length = send_msg (res_buf);
if (length < 0)
return -1;
if (read_response (res_buf) < 0)
return -1;
if (strstr (res_buf, "227") != res_buf)
return 0;
length = sscanf (res_buf, "%d %s %s %s (%u,%u,%u,%u,%u,%u)",
&a, &t[1], &t[2], &t[3], &h1, &h2, &h3, &h4, &p1, &p2);
if (length != 10) {
fprintf (stderr, "PASV scan failure!\n");
return -1;
}
struct sockaddr_in data_addr;
memset (&data_addr, 0, sizeof (struct sockaddr_in));
data_addr.sin_addr.s_addr = htonl ((h1 << 24) | ((h2 & 0xff) << 16) | ((h3 & 0xff) << 8) | (h4 & 0xff));
data_addr.sin_family = AF_INET;
data_addr.sin_port = htons (((p1 & 0xff) << 8) | (p2 & 0xff));
data_fd = socket (PF_INET, SOCK_STREAM, 0);
if (data_fd < 0) {
perror ("Data Socket Creation Failed");
return -1;
}
int scode = connect (data_fd, (const struct sockaddr *)&data_addr, sizeof (data_addr));
if (scode < 0)
return -1;
return data_fd;
}
int nlst_cmd (const char *path, char *response)
{
char buffer[BUF_SIZE];
int data_fd;
ssize_t length;
char *res_buf = response == NULL ? buffer : response;
data_fd = pasv_cmd (NULL);
if (data_fd <= 0)
return data_fd;
length = rand_cmd ("nlst", path, res_buf);
if (length < 0)
return -1;
if (strstr (res_buf, "150 ") == res_buf || strstr (res_buf, "125 ") == res_buf) {
memset (res_buf, 0, BUF_SIZE);
while (read (data_fd, res_buf, BUF_SIZE) > 0) {
fprintf (stdout, "%s", res_buf);
memset (res_buf, 0, BUF_SIZE);
}
length = read_response (res_buf);
if (length < 0)
return -1;
}
close (data_fd);
return 1;
}
int get_cmd (const char *file, char *response)
{
char buffer[BUF_SIZE];
int data_fd, file_fd;
ssize_t length, w_len;
char *res_buf = response == NULL ? buffer : response;
// check if file exists so we do not overwrite it
file_fd = open (file, O_WRONLY | O_CREAT | O_EXCL, 0777);
if (file_fd == -1) {
perror ("Failed to create the file");
fprintf (stderr, "Rename the file on disk first then call get again.\n");
return 1;
}
data_fd = pasv_cmd (NULL);
if (data_fd <= 0)
return data_fd;
length = rand_cmd ("retr", file, res_buf);
if (length < 0)
return -1;
if (strstr (res_buf, "150 ") == res_buf || strstr (res_buf, "125 ") == res_buf) {
memset (res_buf, 0, BUF_SIZE);
while ((length = read (data_fd, res_buf, BUF_SIZE)) > 0) {
w_len = write (file_fd, res_buf, length);
if (w_len < 0 || length < 0) {
perror ("An Error Occuered during file transfer. Closing Client");
close (data_fd);
close (file_fd);
return -1;
}
memset (res_buf, 0, BUF_SIZE);
}
length = read_response (res_buf);
if (length < 0)
return -1;
}
close (data_fd);
close (file_fd);
return 1;
}
int put_cmd (const char *file, char *response)
{
char buffer[BUF_SIZE];
int data_fd, file_fd;
ssize_t length, w_len;
char *res_buf = response == NULL ? buffer : response;
file_fd = open (file, O_RDONLY);
if (file_fd == -1) {
perror ("failed to open the file");
return 1;
}
data_fd = pasv_cmd (NULL);
if (data_fd <= 0)
return data_fd;
length = rand_cmd ("stor", file, res_buf);
if (length < 0)
return -1;
if (strstr (res_buf, "150 ") == res_buf || strstr (res_buf, "125 ") == res_buf) {
memset (res_buf, 0, BUF_SIZE);
while ((length = read (file_fd, res_buf, BUF_SIZE)) > 0) {
w_len = send (data_fd, res_buf, length, 0);
if (w_len != length) {
perror ("An Error Occuered during file transfer. Closing Client");
close (data_fd);
close (file_fd);
return -1;
}
memset (res_buf, 0, BUF_SIZE);
}
close (data_fd);
close (file_fd);
length = read_response (res_buf);
if (length < 0)
return -1;
}
close (data_fd);
close (file_fd);
return 1;
}
int quit_cmd (char *response)
{
char buffer[BUF_SIZE];
memset (buffer, 0, BUF_SIZE);
snprintf (buffer, BUF_SIZE, "%s", "quit");
ssize_t length = send_msg (buffer);
if (length < 0)
return -1;
char *res_buf = response == NULL ? buffer : response;
read_response (res_buf);
cleanup();
return -2;
}
int bin_type (const char *response)
{
if (strstr (response, "230 ")) {
ssize_t length = rand_cmd ("type", "I", NULL);
if (length < 0)
return -1;
}
return 1;
}
ssize_t send_msg (const char *msg)
{
char buffer[BUF_SIZE];
ssize_t length;
memset (buffer, 0, 1024);
length = snprintf (buffer, 1024, "%s%s", msg, CRLF);
if (length != send (sfd, buffer, length, 0)) {
perror ("Couldn't sent the complete msg. Exiting..");
return -1;
}
return length;
}
ssize_t read_response (char *response)
{
memset (response, 0, BUF_SIZE);
ssize_t length = read (sfd, response, BUF_SIZE);
if (length <= 0) {
perror ("Error while reading from server. Terminiating Control Connection");
return -1;
}
printResponse (stdout, response);
int i_rcode;
char buf[24];
memset (buf, 0, 24);
// check for multiline response: d{3}-
if ((sscanf (response, "%u%s", &i_rcode, buf) == 2) && (strstr (buf, "-") == buf)) {
memset (buf, 0, 24);
snprintf (buf, 24, "%d%s", i_rcode, " End");
// check if the entire response hasn't been sent
if (strstr (response, buf) == NULL) {
while (1) {
memset (response, 0, BUF_SIZE);
length = read (sfd, response, BUF_SIZE);
fprintf(stdout, "%s", response);
if (strstr (response, buf) != NULL)
break;
}
}
}
// copy the response to manipulate it
// without modifing the original buffer
char rcopy[length];
memset (rcopy, 0, length);
snprintf (rcopy, BUF_SIZE, "%s", response);
char *rcode = strtok (rcopy, " ");
if (strcmp (rcode, "421") == 0) {
printf ("%s\n", "Server Closing Control Connection. Shutting Down.");
return -1;
}
return length;
}
int check_argc (const char *args, unsigned int exepcted)
{
int count = 1;
char argcpy[BUF_SIZE];
if (args == NULL) {
return exepcted == 0;
}
// make a copy of parameter for count checking
memset (argcpy, 0, BUF_SIZE);
snprintf (argcpy, BUF_SIZE, "%s", args);
char *param = strtok (argcpy, " \t\n\f\r\v");
while (param != NULL) {
param = strtok (NULL, " \t\n\f\r\v");
if (param != NULL)
count++;
}
return count == exepcted;
}
void cleanup()
{
if (sfd != -1) {
close (sfd);
sfd = -1;
}
}