/*
* serv.c - server creating AF_UNIX socket used by cli.c
* compile with gcc -g -Wall serv.c -o serv
*/

#include <sys/types.h>
#ifdef __linux__
#include <linux/socket.h>
#else
#include <sys/socket.h>
#endif
#include <sys/un.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <fcntl.h>
#include <sys/file.h>
#include <errno.h>
#include <unistd.h>

#define USOCK "./usock"
#define BACKLOG 5

static sig_atomic_t sigreceived = 0;
static int s = 0, c = 0;

static void add_flags(int fd, int flags)
{
int val;

if ((val = fcntl(fd, F_GETFL, 0)) < 0) {
perror("add_flags(): fcntl(F_GETFL)");
exit(1);
}
val |= flags;
if ((val = fcntl(fd, F_SETFL, val)) < 0) {
perror("add_flags(): fcntl(F_SETFL)");
exit(1);
}
}

static void mysig(int sig)
{
char buf[200];
int ret;

fprintf(stderr, "Signal %d received #%d\n", sig, ++sigreceived);
if (!c) {
if((c = accept(s, NULL, NULL)) < 0) {
perror("accept()");
exit(1);
}
fprintf(stderr, "accept() OK\n");
memset(buf, 0, 200);
/* ret = recv(c, buf, 200, 0); */
ret = recv(c, buf, 200, MSG_WAITALL);
if (ret < 0) {
perror("read()");
return;
}
fprintf(stderr, "received %d bytes <%s>\n", ret, buf);
return;
} else { /* this branch is never taken on Linux */
memset(buf, 0, 200);
ret = read(c, buf, 200);
if (ret < 0) {
perror("read()");
return;
}
fprintf(stderr, "received %d bytes <%s>\n", ret, buf);
}
return ;
}

int main(int argc, char *argv[])
{
int len;
struct sockaddr_un sa;
struct sigaction act;
pid_t pid = getpid();

act.sa_handler = mysig;
act.sa_flags = 0;
sigemptyset(&act.sa_mask);
if (sigaction(SIGPOLL, &act, NULL) < 0) {
perror("sigaction(SIGPOLL)");
exit(1);
}

(void)unlink(USOCK);
s = socket(PF_UNIX, SOCK_STREAM, 0);
if (s < 0) {
perror("socket(PF_UNIX, SOCK_STREAM)");
exit(1);
}

if (fcntl(s, F_SETOWN, pid) < 0) {
perror("fcntl(s, F_SETOWN)");
exit(1);
}

add_flags(s, FASYNC);

len = sizeof(sa);
sa.sun_family = AF_UNIX;
strcpy(sa.sun_path, USOCK);
if (bind(s, (struct sockaddr *)&sa, len) < 0) {
perror("bind()");
exit(1);
}
fprintf(stderr, "bind() OK\n");
if (listen(s, BACKLOG) < 0) {
perror("listen()");
exit(1);
}
fprintf(stderr, "listen() OK\n");

while (1)
pause();

/* not reached */
return 0;
}

/*
* cli.c - client connecting to AF_UNIX socket created by serv.c
* compile with gcc -g -Wall cli.c -o cli
*/

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

#define USOCK "./usock"

int main(int argc, char *argv[])
{
int fd, len;
struct sockaddr_un sa;
const char *buf1 = "Hello from client";
const int len1 = strlen(buf1);
const char *buf2 = "Goodbye from client";
const int len2 = strlen(buf2);
const char *buf3 = "Cheerio from client";
const int len3 = strlen(buf2);

fd = socket(PF_UNIX, SOCK_STREAM, 0);
if (fd < 0) {
perror("cli: socket(PF_UNIX,SOCK_STREAM)");
exit(1);
}
sa.sun_family = AF_UNIX;
strcpy(sa.sun_path, USOCK);
len = sizeof(sa);
if (connect(fd, (struct sockaddr *)&sa, len) < 0) {
perror("cli: connect()");
exit(1);
}
sleep(1);
if (send(fd, buf1, len1, 0) != len1) {
perror("cli: send(buf1)");
exit(1);
}
sleep(1);
if (send(fd, buf2, len2, 0) != len2) {
perror("cli: send(buf2)");
exit(1);
}
sleep(1);
if (send(fd, buf3, len3, 0) != len3) {
perror("cli: send(buf3)");
exit(1);
}
return 0;
}

if you expect help, you could at least bother to ask a real question and put a code dump in some sort of context...

server part works only one time...

lol
give a detailed essay on whats wrong here

i take it back, that's worse than nothing at all. and still no please or thankyou...

Thank you for your time.

my appologies, that was a but short there... but if you want help from others then you need to provide information for them to work with. you have said nothing to actaully give any idea what is meant to happen in a correct scenario, let alone what is going wrong. you have to help yourself if you expect otehrs to do the same.

Moved: This thread is more suitable in Programming and has been moved accordingly to help your thread/question get the exposure it deserves.

That said: kewp is right :}

The code is short and simple. To describe it in words will add more fog than clear existing one. The problem I have is that server gets only one message from the single client and I don't know how to make server respond every time. Please, look into the code it is really simple. There is something very small but very important what I don't know that creates this problem.
http://www.uwsg.iu.edu/hypermail/lin...06.0/0189.html

hi harvest,

you have wrong sigaction code (mysig(int sig)).
you try reading from closed socket after first client.
your global variable 'c' must be zero after job.
insert something like

close(c);
c = 0;

It will be

if (ret < 0) {
perror("read()");
return;
}
fprintf(stderr, "received %d bytes <%s>\n", ret, buf);
close(c); // <----- see here
c = 0; // <-----
return;
}
...