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/* userver.c - simple server for Unix domain sockets */
/* Waits for a connection on the ./sample-socket Unix domain
socket. Once a connection has been established, copy data
from the socket to stdout until the other end closes the
connection, and then wait for another connection to the socket. */
#include <stdio.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
#define _PATH_LOG "/dev/log"
/* issue an error message via perror() and terminate the program */
void die(char * message) {
perror(message);
exit(1);
}
/* Copies data from file descriptor 'from' to file descriptor 'to'
until nothing is left to be copied. Exits if an error occurs. */
void copyData(int from, int to) {
char buf[1024];
int amount;
while ((amount = read(from, buf, sizeof(buf))) > 0) {
if (write(to, buf, amount) != amount) {
die("write");
return;
}
}
if (amount < 0)
die("read");
}
int main(void) {
struct sockaddr_un address;
int fd, conn;
size_t addrLength;
/* Remove any preexisting socket (or other file) */
unlink(_PATH_LOG);
memset(&address, 0, sizeof(address));
address.sun_family = AF_UNIX; /* Unix domain socket */
strncpy(address.sun_path, _PATH_LOG, sizeof(address.sun_path));
if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
die("socket");
/* The total length of the address includes the sun_family
element */
addrLength = sizeof(address.sun_family) +
strlen(address.sun_path);
if (bind(fd, (struct sockaddr *) &address, addrLength))
die("bind");
if (chmod(_PATH_LOG, 0666) < 0)
die("chmod");
if (listen(fd, 5))
die("listen");
while ((conn = accept(fd, (struct sockaddr *) &address,
&addrLength)) >= 0) {
printf("---- getting data\n");
copyData(conn, fileno(stdout));
printf("---- done\n");
close(conn);
}
if (conn < 0)
die("accept");
close(fd);
return 0;
}
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