unix domain sockets

jimi_xyz_at_hotmail.com
Date: 01/31/05 

Date: 31 Jan 2005 12:00:31 -0800

Ok I have written a domain socket, it seems to connect fine, but for
some reason when i #define NAME "my_sock" it doesn't create the socket
the full name, if i do this in the program it creates a file called
"my_soc" when it should be "my_sock". Another problem I have is when i
try to run the server i get a bind error, that says "address allready
in use", so in order for the server to run multiple times I need to do
a system("my_soc"), this isn't right, I beleive unlink should take care
of this problem when the program first runs, but it doesn't. Last
question is how would i go about sending a signal from the client to
the server, example the user sends c-control from the client, the
server says "signal received", then writes back to the client, "server
recieved signal".

server code...

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>

#define NAME "my_sock"

main(void)
{
int orig_sock;
int new_sock;
int clnt_len;
int i;
int true = 1;
int pid;
static struct sockaddr_un clnt_adr, serv_adr;

static char buf[200];

void clean_up(int, char *);

if((orig_sock = socket(AF_LOCAL, SOCK_STREAM, 0)) < 0)
{
perror("generate error");
exit(1);
}

unlink(NAME);
bzero(&serv_adr, sizeof(serv_adr));
serv_adr.sun_family = AF_LOCAL;
strcpy(serv_adr.sun_path, NAME);

/*setsockopt(orig_sock, SOL_SOCKET, SO_REUSEADDR, (char *)&true,
sizeof(true));
*/
if (bind(orig_sock, (struct sockaddr *) &serv_adr,
sizeof(serv_adr.sun_family) + strlen(serv_adr.sun_path)) < 0)
{
perror("!!bind error");
clean_up(orig_sock, NAME);
exit(2);
}

listen(orig_sock, 1);
clnt_len = sizeof(clnt_adr);

for(;;)
{
if ((new_sock = accept( orig_sock, (struct sockaddr *) &clnt_adr,
&clnt_len)) < 0 )
{
perror("accept error");
clean_up(orig_sock, NAME);
exit(3);
}

pid = fork();

switch(pid)
{
case -1:
perror("fork error:");
exit(1);

case 0:
/*read from socket descriptor and print to screen*/
sleep(1);
read(new_sock, buf, sizeof(buf));
printf("\n%s\n", buf);
/*////////////////////////////////////////////////*/
exit(0);

default:
close(new_sock);
clean_up(orig_sock, NAME);
exit(0);
}
}/*end switch*/
}/*end main*/

void clean_up(int sd, char *the_file)
{
close(sd);
unlink(the_file);
system("rm my_soc");
}

client code..

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>

#define NAME "my_sock"
int BUFFSIZE = 2000;
main(void)
{
int orig_sock;
int i;
int c;
char inbuf[BUFFSIZE];

static struct sockaddr_un serv_adr;

static char buf[10];

if((orig_sock = socket(AF_LOCAL, SOCK_STREAM, 0)) < 0)
{
perror("genarate error");
exit(1);
}

serv_adr.sun_family = AF_LOCAL;
strcpy(serv_adr.sun_path, NAME);

if(connect( orig_sock, (struct sockaddr *) &serv_adr,
sizeof(serv_adr.sun_family) + strlen(serv_adr.sun_path)) < 0)
{
perror("connect error");
exit(1);
}

for(i = 0; (i < BUFFSIZE - 1) && ((c = getchar()) != '\n'); i++)
{
inbuf[i] = c;
}
inbuf[i] = '\0';

write(orig_sock, inbuf, BUFFSIZE);

close(orig_sock);
exit(0);
}/*end main*/

thank you any input will help,
James Barnett

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