Once upon a time, I knew how to use Unix sockets.
Web Server
Supports binary files, ~user, http 0.9 and 1.0, and several other features. Other projects from this class (not shown) include a port scanner, file transfer utility, and chat program.
server.cc
/*Shawn O'Neil's Program */
#include <stream.h>
#include <stdio.h>
#include <string.h>
#include <netinet/in.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <pwd.h>
#include <dirent.h>
#include <netdb.h>
#include <fcntl.h>
using namespace std;
#define NOTFOUND 1
#define DENIED 2
#define SYSTEM 3
#define MSIE 4
#define EUCLID 5
const int BUFSIZE=500;
int cliaddr = 0;
int MakeSocket(char *port) {
int s; //socket to make
int fd; //the file descriptor to return
int len; //lenght of something apparently
int ret; //check errors on this!
int portnum;
int *ppointer; //port number pointer
ppointer = &portnum;
struct servent *sp; //struct for finding port num
//if work like "telnet" is entered
struct sockaddr_in my_addr; //my address info
//FILLING OUT MY ADDR INFO
my_addr.sin_family = AF_INET; //set my family type
sscanf(port, "%d", ppointer); //set my portnum to use
if(portnum > 0)
my_addr.sin_port = htons(portnum);
else{
sp=getservbyname(port, "tcp");
portnum = sp->s_port;
my_addr.sin_port = sp->s_port;
}
char localhostname[255];
if((gethostname(localhostname, 255)) < 0){ //um, so now i have
perror("Could not get my Hostname: "); //the dns name of this
exit(1);
} //machine
struct hostent *hp;
if((hp = gethostbyname(localhostname)) == 0){
perror("Couldn't gethostbyname:");
exit(1);
}
bcopy((char *)hp->h_addr, (char *)&my_addr.sin_addr, hp->h_length);
s = socket(my_addr.sin_family, SOCK_STREAM, 0);
if(s < 0){
perror("Couldn't Make Socket:");
exit(1);
}
ret = bind(s, (struct sockaddr *)&my_addr, sizeof(my_addr));
if(ret < 0){
perror("Couldn't bind socket: ");
exit(1);
}
listen(s, 3);
return s;
}
int makeFileDescriptor(int s){
int fd;
struct sockaddr_in client_addr;
int sa_len = sizeof(client_addr);
fd = accept(s, (struct sockaddr *)&client_addr, (unsigned int *)&sa_len);
if(fd < 0){
perror("Couldn't Create File Descriptor: ");
exit(1);
}
cout << endl << endl << endl;
cout << "Made fd: " << fd << ",";
cliaddr = (unsigned int)client_addr.sin_addr.s_addr;
cout << " address is " << (unsigned int)client_addr.sin_addr.s_addr << ",";
cout << " family " << client_addr.sin_family << ",";
cout << " port " << ntohs(client_addr.sin_port) << endl;
return fd;
}
char * turnNumberToBase(int target, int base)
{
int length = 0;
int number = 0;
char outstring[100];
bool palindrome = true;
char instring[100];
char *in;
in = &instring[0];
char *out;
out = &outstring[0];
while(target != 0)
{
length++;
if(target%base > 9)
*in = target%base+ '7';
else
*in = target%base + '0';
in++;
target = target/base;
}
*in = 0;
in = &instring[0];
for(int x = length-1; x >=0; x--)
{
*out = *(in+x);
out++;
}
*out = 0;
out = &outstring[0];
while(*in != 0)
{
if(*in != *out)
palindrome = false;
in++;
out++;
}
out = &outstring[0];
return out;
}
void sendError(int fd, int type, int version)
{
if(version == 0)
{
if(type == NOTFOUND)
{
write(fd, "404 not found", 13);
}
else if(type == DENIED)
{
write(fd, "403 forbiddenness", 17);
}
else if(type == SYSTEM)
{
write(fd, "500 system error", 16);
}
else if(type == MSIE)
{
write(fd, "No MSIE allowed", 15);
}
}
else if(version == 1)
{
if(type == NOTFOUND)
{
char header[1000];
strcpy(header, "");
strcat(header, "HTTP/1.0 404 Not found asshole, you suck\n");
strcat(header, "Content-type: text/plain\n");
strcat(header, "Content-length: ");
strcat(header, "29");
strcat(header, "\n\n");
write(fd, header, strlen(header));
write(fd, "404 not found, mr version 1.0", 29);
}
else if(type == DENIED)
{
char header[1000];
strcpy(header, "");
strcat(header, "HTTP/1.0 403 forbidden idiot, you suck\n");
strcat(header, "Content-type: text/plain\n");
strcat(header, "Content-length: ");
strcat(header, "29");
strcat(header, "\n\n");
write(fd, header, strlen(header));
write(fd, "403 forbidden, mr version 1.0", 29);
}
else if(type == SYSTEM)
{
char header[1000];
strcpy(header, "");
strcat(header, "HTTP/1.0 500 God I'm dying\n");
strcat(header, "Content-type: text/plain\n");
strcat(header, "Content-length: ");
strcat(header, "32");
strcat(header, "\n\n");
write(fd, header, strlen(header));
write(fd, "500 system error, mr version 1.0", 32);
}
else if(type == MSIE || type == EUCLID)
{
char header[1000];
strcpy(header, "");
strcat(header, "HTTP/1.0 500 God I'm dying\n");
strcat(header, "Content-type: text/plain\n");
strcat(header, "Content-length: ");
strcat(header, "44");
strcat(header, "\n\n");
write(fd, header, strlen(header));
if(type == EUCLID)
write(fd, "You simply can't EUCLID here, mr version 1.0", 44);
else
write(fd, "You simply can't use IE here, mr version 1.0", 44);
}
}
else if(version == 2)
{
if(type == NOTFOUND)
{
char header[1000];
strcpy(header, "");
strcat(header, "HTTP/1.1 404 Not found asshole, you suck\n");
strcat(header, "Content-type: text/plain\n");
strcat(header, "Connection: close\n");
strcat(header, "Content-length: ");
strcat(header, "29");
strcat(header, "\n\n");
write(fd, header, strlen(header));
write(fd, "404 not found, mr version 1.1", 29);
}
else if(type == DENIED)
{
char header[1000];
strcpy(header, "");
strcat(header, "HTTP/1.1 403 forbidden idiot, you suck\n");
strcat(header, "Content-type: text/plain\n");
strcat(header, "Connection: close\n");
strcat(header, "Content-length: ");
strcat(header, "29");
strcat(header, "\n\n");
write(fd, header, strlen(header));
write(fd, "403 forbidden, mr version 1.1", 29);
write(1, header, strlen(header));
write(1, "403 forbidden, mr version 1.1", 29);
}
else if(type == SYSTEM)
{
char header[1000];
strcpy(header, "");
strcat(header, "HTTP/1.1 500 God I'm dying\n");
strcat(header, "Content-type: text/plain\n");
strcat(header, "Connection: close\n");
strcat(header, "Content-length: ");
strcat(header, "32");
strcat(header, "\n\n");
write(fd, header, strlen(header));
write(fd, "500 system error, mr version 1.1", 32);
}
else if(type == MSIE || type == EUCLID)
{
char header[1000];
strcpy(header, "");
strcat(header, "HTTP/1.1 500 God I'm dying\n");
strcat(header, "Content-type: text/plain\n");
strcat(header, "Connection: close\n");
strcat(header, "Content-length: ");
strcat(header, "24");
strcat(header, "\n\n");
write(fd, header, strlen(header));
if(type == EUCLID)
write(fd, "EUCLID!!, mr version 1.1", 24);
else
write(fd, "no MSIE!, mr version 1.1", 24);
}
}
}
void doStuff(int fd, int option)
{
int len = 0; // length of reveived data
char buf[BUFSIZE]; // buffer in which to read
char string_get[512];
char string_request[512];
char string_version[50];
char string_host[50];
char string_hostname[512];
if(option == 0) //yay! server some pages, man
{
struct stat servstat; //DELETE THIS STRUCT
struct dirent *direntry; //DELETE THIS STRUCT
struct passwd *pwentry;
if((len = read(fd, buf, BUFSIZE-1)) < 0) //
{ //
perror("Reading from client"); //
exit(1); //
} // Read what they said,
buf[len] = 0;
if(len = sscanf(buf, "%s %s %s %s %s", string_get, string_request, string_version, string_host, string_hostname) < 0) // string_request should = what they actually asked for (for all versions of HTML)
{ //
perror("Stupid scanner. I bet this error never even gets shown"); //
exit(1); //
} //
//cout << "get is: " << string_get << " request is: " << string_request << " version is: " << string_version << " host is: " << string_host << " hostname is: " << string_hostname << endl;
int version = 0; //version = 0 if 0.9, 1 if 1.0 and 2 if 1.1
if(strstr(string_version, "1.0") != 0)
version = 1;
else if(strstr(string_version, "1.1") != 0)
version = 2;
/* ------------MSIE BREAK CODE------------*/
char* msie = strstr(buf, "MSIE");
if(msie != 0)
{
sendError(fd, MSIE, version);
exit(1);
}
/* ------------end MSIE BREAK CODE------------*/
/* -------------EUCLID BREAK CODE ------------*/
cout << "cliaddr is now: " << cliaddr << endl;
if(cliaddr == 163671750)
{
sendError(fd, EUCLID, version);
exit(1);
}
/* ------------- end EUCLID BREAK CODE ------------*/
/*----------- ~user notation code --------- */
char serving[500]; //what to open
if(string_request[0] == '/' && string_request[1] == '~') // All this for handing ~user notation
{
char username[500];
char *p;
p = &string_request[2];
int i = 0;
for(i; *p != '/' && *p != 0; i++)
{
username[i] = *p;
p++;
}
username[i+1] = 0;
pwentry = getpwnam(username);
if(pwentry == 0)
{
perror("couldnt getpwnam"); //send an error and delete structs
sendError(fd, NOTFOUND, version);
exit(1);
}
strcpy(serving, pwentry->pw_dir); //
strcat(serving, "/pub");
cout << username << "'s home dir is " << serving << endl;
char *q;
q = &serving[strlen(serving)];
while(*p != 0)
{
*q = *p;
p++; q++;
}
*q = 0;
cout << "serving is now " << serving << endl;
}
else //directly asking, ie no ~user notation
{
strcpy(serving, string_request);
}
/* -------------- end ~user notation code --------- */
int ret = stat(serving, &servstat);
if(ret < 0)
{
perror("couldnt stat");
sendError(fd, NOTFOUND, version);
exit(1); // probably send them an error before exiting, and remember to delete the structs
}
/* ------------- serving directory -------------------*/
if(S_ISDIR(servstat.st_mode) && (servstat.st_mode & 4)) //This is a directory...
{
DIR *directory;
directory = opendir(serving);
if(directory == 0)
{
perror("couldnt open directory");
sendError(fd, SYSTEM, version);
exit(1); // probably send them an error before exiting, and remember to delete the structs
}
direntry = readdir(directory);
char dirlist[10000];
dirlist[0]= 0;
strcat(dirlist, "<BODY>\n");
while (direntry != 0)
{
char pathtofile[1000];
strcpy(pathtofile, "");
strcat(pathtofile, serving);
strcat(pathtofile, "/");
strcat(pathtofile, direntry->d_name);
strcat(dirlist, "<A href=\"");
strcat(dirlist, pathtofile);
strcat(dirlist, "\">");
strcat(dirlist, direntry->d_name);
strcat(dirlist, "</A><BR>\n");
direntry = readdir(directory);
}
strcat(dirlist, "</BODY>\n");
// cout << dirlist << " is " << strlen(dirlist) << " bytes long" <<endl;
closedir(directory);
if(version == 0)
write(fd, dirlist, strlen(dirlist));
else if (version == 1)
{
char header[1000];
strcpy(header, "");
strcat(header, "HTTP/1.0 200 Ok, you suck\n");
strcat(header, "Content-type: text/html\n");
strcat(header, "Content-length: ");
char *contlength;
contlength = turnNumberToBase(strlen(dirlist), 10);
strcat(header, contlength);
strcat(header, "\n\n");
write(fd, header, strlen(header));
write(fd, dirlist, strlen(dirlist));
}
else if (version == 2)
{
char header[1000];
strcpy(header, "");
strcat(header, "HTTP/1.1 200 Ok, you suck\n");
strcat(header, "Content-type: text/html\n");
strcat(header, "Connection: close\n");
strcat(header, "Content-length: ");
cout << "length of content should match " << strlen(dirlist) << endl;
char *contlength;
contlength = turnNumberToBase(strlen(dirlist), 10);
strcat(header, contlength);
strcat(header, "\n\n");
write(fd, header, strlen(header));
write(fd, dirlist, strlen(dirlist));
cout << "Sending: " << endl;
write(1, header, strlen(header));
write(1, dirlist, strlen(dirlist));
}
}
/* --------------- end serving directory ---------------- */
/* --------------- serving file --------------------------*/
else if(servstat.st_mode & 4) //This is a file....
{
int in = open(serving, O_RDONLY); //
if(in == -1) //
{ // Opening file...
perror("openingfile"); //
sendError(fd, NOTFOUND, version);
exit(1); // send an error
} //
char writebuf[BUFSIZE]; //
if((len = read(in, writebuf, BUFSIZE-1)) < 1) //
{ //
perror("First read on file");
sendError(fd, SYSTEM, version); //
exit(1); // send an error
} // Give it to them
char* test; //used for testing strstr's
if(version == 1)
{
char header[1000];
strcpy(header, "");
strcat(header, "HTTP/1.0 200 Ok, you suck\n");
if((test = strstr(serving, ".htm")) != 0 || (test = strstr(serving, ".html")) != 0)
strcat(header, "Content-type: text/html\n");
else if((test = strstr(serving, ".jpg")) != 0)
strcat(header, "Content-type: image/jpeg\n");
else if((test = strstr(serving, ".gif")) != 0)
strcat(header, "Content-type: image/gif\n");
else
strcat(header, "Content-type: text/plain\n"); // correct this to match what the file is
strcat(header, "Content-length: ");
int filesize = servstat.st_size;
char *contlength;
contlength = turnNumberToBase(filesize, 10);
strcat(header, contlength);
strcat(header, "\n\n");
write(fd, header, strlen(header));
}
else if(version == 2)
{
char header[1000];
strcpy(header, "");
strcat(header, "HTTP/1.0 200 Ok, you suck\n");
if((test = strstr(serving, ".htm")) != 0 || (test = strstr(serving, ".html")) != 0)
strcat(header, "Content-type: text/html\n");
else if((test = strstr(serving, ".jpg")) != 0)
strcat(header, "Content-type: image/jpeg\n");
else if((test = strstr(serving, ".gif")) != 0)
strcat(header, "Content-type: image/gif\n");
else
strcat(header, "Content-type: text/plain\n"); // correct this to match what the file is
strcat(header, "Connection: close\n");
strcat(header, "Content-length: ");
int filesize = servstat.st_size;
char *contlength;
contlength = turnNumberToBase(filesize, 10); // TEST
strcat(header, contlength);
strcat(header, "\n\n");
write(fd, header, strlen(header));
cout << "Sending: " << endl;
write(1, header, strlen(header)+1);
}
int count = len;
while(len > 0)
{
write(fd, writebuf, len);
len = read(in, writebuf, BUFSIZE-1);
count+=len;
}
//cout << "I wrote " << count << " bytes" << endl;
close(in); // Probably not necessary as this child will kill itself anyway.
}
else //forbidden!!!! mwa ha hah
{
cout << "Error, permission denied. " << endl;
sendError(fd, DENIED, version); // for gods sake send him an error
exit(1);
}
/* -------------- end serving file -------------------*/
delete(&servstat);
delete(direntry);
delete(pwentry);
close(fd); // Close file descriptors
}
else //he connected but didnt do anything, bitch him out
{
write(fd, "Use a webserver, dumbass", 25); // for gods sake send him an error
}
exit(1); //oh my god kill the process for christs sake
}
main(int argc, char *argv[])
{
int s; //socket descriptor
int fd; // file descriptor
int len; // length of reveived data
char buf[BUFSIZE]; // buffer in which to read
int ret; //various system call crap
char string_one[512];
char string_two[512];
struct timeval tv;
fd_set rfds; //set of file descriptors
int max; //biggest file descripter in set
s = MakeSocket(argv[1]);
//fd = makeFileDescriptor(s);
if (s < 1)
{
perror("Making socket");
exit(1);
}
while(1)
{
int fd = makeFileDescriptor(s);
int pid = fork();
if(pid < 0)
{
perror("Fork Broke");
exit(1);
}
else if(pid == 0) //I am the child
{
FD_ZERO(&rfds); //initialize all the fds that we shall pay attention to to 0
FD_SET(fd, &rfds); //pay attention to the socket, dammit
max = fd;
tv.tv_sec = 1;
tv.tv_usec = 50000; //millionths of a second
ret = select(max+1, &rfds, 0, 0, &tv); //who do we listen to?
if(ret > 0) //do what they asked for
{
doStuff(fd, 0);
}
else
{
cout << "tv timed out, outputting default" << endl;
doStuff(fd, 1);
}
}
else
{
close(fd);
}
}
}Command Server
A little utility to run commands on a linux box via the web and see the results;
limited to fortune and echo, as in http://server:port/echo_hi_there.
server.cc
/*Shawn O'Neil's Program */
#include <stream.h>
#include <stdio.h>
#include <string.h>
#include <netinet/in.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <netdb.h>
#include <fcntl.h>
using namespace std;
const int BUFSIZE=500;
int numConnects = 0; //how many people are connected
int connection[100]; //the array of connections, file descriptors
int MakeSocket(char *port) {
int s; //socket to make
int fd; //the file descriptor to return
int len; //lenght of something apparently
int ret; //check errors on this!
int portnum;
int *ppointer; //port number pointer
ppointer = &portnum;
struct servent *sp; //struct for finding port num
//if work like "telnet" is entered
struct sockaddr_in my_addr; //my address info
//FILLING OUT MY ADDR INFO
my_addr.sin_family = AF_INET; //set my family type
sscanf(port, "%d", ppointer); //set my portnum to use
if(portnum > 0)
my_addr.sin_port = htons(portnum);
else{
sp=getservbyname(port, "tcp");
portnum = sp->s_port;
my_addr.sin_port = sp->s_port;
}
char localhostname[255];
if((gethostname(localhostname, 255)) < 0){ //um, so now i have
perror("Could not get my Hostname: "); //the dns name of this
exit(1);
} //machine
struct hostent *hp;
if((hp = gethostbyname(localhostname)) == 0){
perror("Couldn't gethostbyname:");
exit(1);
}
bcopy((char *)hp->h_addr, (char *)&my_addr.sin_addr, hp->h_length);
s = socket(my_addr.sin_family, SOCK_STREAM, 0);
if(s < 0){
perror("Couldn't Make Socket:");
exit(1);
}
ret = bind(s, (struct sockaddr *)&my_addr, sizeof(my_addr));
if(ret < 0){
perror("Couldn't bind socket: ");
exit(1);
}
listen(s, 3);
return s;
}
int makeFileDescriptor(int s){
int fd;
struct sockaddr_in client_addr;
int sa_len = sizeof(client_addr);
fd = accept(s, (struct sockaddr *)&client_addr, (unsigned int *)&sa_len);
if(fd < 0){
perror("Couldn't Create File Descriptor: ");
exit(1);
}
//cout << "Made fd: " << fd << endl;
return fd;
}
int splitLine(char *input, char *word[])
{
int count = 0;
int currentWordLen;
bool inword=false;
for(int i = 1; input[i] != 0; i++) //start at 1 to get rid of leading '/'
{
if(input[i] == '_')
{
inword = false;
word[count][currentWordLen] = 0;
count++;
currentWordLen = 0;
}
else
{
word[count][currentWordLen++] = input[i];
inword = true;
}
}
word[count][currentWordLen] = 0;
count++;
return count;
}
void doStuff(int fd, int option)
{
int len; // length of reveived data
char buf[BUFSIZE]; // buffer in which to read
char string_one[512];
char string_two[512];
if(option == 0) //outputting with options asked for
{
if(len = read(fd, buf, BUFSIZE-1) < 0)
{
perror("Reading error");
exit(1);
}
if(len = sscanf(buf, "%s %s", string_one, string_two) < 0)
{
perror("Stupid Scanner");
exit(1);
}
char *word[10];
for(int i = 0; i < 10; i++)
{
word[i] = new char[20];
}
int count = splitLine(string_two, word);
word[count] = 0;
//cout << "Execing " << count << " commands: ";
//for(int i = 0; i < count; i++)
// cout << word[i] << " ";
//cout << endl;
if(len = dup2(fd, 1) < 0)
{
perror("Couldnt dup");
exit(1);
}
if(strcmp(word[0],"fortune") == 0 || strcmp(word[0],"echo") == 0 || strcmp(word[0],"man") == 0)
execvp(word[0], word);
else if(strcmp(word[0],"listfortunes") == 0)
execlp("ls", "ls", "-R", "/usr/share/fortune", 0);
else
execlp("cat", "cat", "helpfile", 0);
}
else //Outputting default down the fd
{
if(len = dup2(fd, 1) < 0)
{
perror("Couldnt dup");
exit(1);
}
execlp("fortune", "fortune", 0);
}
cout << "Couldn't exec for some reason. Try something like http://server:port/fortune_-o OR http://server:port/help" << endl;
exit(1); //this shouldnt happen
}
main(int argc, char *argv[])
{
int s; //socket descriptor
int fd; // file descriptor
int len; // length of reveived data
char buf[BUFSIZE]; // buffer in which to read
int ret; //various system call crap
char string_one[512];
char string_two[512];
struct timeval tv;
fd_set rfds; //set of file descriptors
int max; //biggest file descripter in set
s = MakeSocket(argv[1]);
//fd = makeFileDescriptor(s);
if (s < 1)
{
perror("Making socket");
exit(1);
}
while(1)
{
int fd = makeFileDescriptor(s);
int pid = fork();
if(pid < 0)
{
perror("Fork Broke");
exit(1);
}
else if(pid == 0) //I am the child
{
FD_ZERO(&rfds); //initialize all the fds that we shall pay attention to to 0
FD_SET(fd, &rfds); //pay attention to the socket, dammit
max = fd;
tv.tv_sec = 0;
tv.tv_usec = 5000; //millionths of a second
ret = select(max+1, &rfds, 0, 0, &tv); //who do we listen to?
if(ret > 0) //do what they asked for
{
doStuff(fd, 0);
}
else
{
cout << "tv timed out, outputting default" << endl;
doStuff(fd, 1);
}
}
else
{
close(fd);
}
}
}