B
balzano_1
Hi, im trying to send text from one pc to anther using C socket
programming, i used send() to send the text, the text i used to send
is a result of a function, the problem is the other side recieves
gibbarish, here are server.c and client.c
------------
server.c
------------
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/wait.h>
#include <signal.h>
#include <sys/utsname.h>
#define MYPORT 3490
#define BACKLOG 10
char *sys_info() //the function returns version of system
{
char *computer=malloc(255*sizeof(char)), *rv=NULL;
struct utsname uts;
if(gethostname(computer, 255) != 0 || uname(&uts) < 0){
fprintf(stderr,"couldnt get host info");
free(computer);
exit(1);
}
rv=uts.version;
return rv;
}
void sigchld_handler(int s)
{
while(wait(NULL) > 0);
}
int main(void)
{
int sockfd, new_fd;
struct sockaddr_in my_addr;
struct sockaddr_in their_addr;
int sin_size;
struct sigaction sa;
int yes=1;
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
perror("socket");
exit(1);
}
if (setsockopt(sockfd,SOL_SOCKET,SO_REUSEADDR,&yes,sizeof(int))
== -1) {
perror("setsockopt");
exit(1);
}
my_addr.sin_family = AF_INET;
my_addr.sin_port = htons(MYPORT);
my_addr.sin_addr.s_addr = INADDR_ANY;
memset(&(my_addr.sin_zero), '\0', 8);
if (bind(sockfd, (struct sockaddr *)&my_addr, sizeof(struct
sockaddr))
== -1) {
perror("bind");
exit(1);
}
if (listen(sockfd, BACKLOG) == -1) {
perror("listen");
exit(1);
}
sa.sa_handler = sigchld_handler; // reap all dead processes
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART;
if (sigaction(SIGCHLD, &sa, NULL) == -1) {
perror("sigaction");
exit(1);
}
while(1) { // main accept() loop
sin_size = sizeof(struct sockaddr_in);
if ((new_fd = accept(sockfd, (struct sockaddr
*)&their_addr,&sin_size)) == -1) {
perror("accept");
continue;
}
printf("server: got connection from %s\n",
inet_ntoa(their_addr.sin_addr));
if (!fork()) {
close(sockfd);
if (send(new_fd, sys_info(), strlen(sys_info()), 0) ==
-1)// this is where i pass the result of the function sys_info() to
send()
perror("ERROR SENDING THE MESSAGE");
close(new_fd);
exit(0);
}
close(new_fd);
}
return 0;
}
-----------
client.c
-----------
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#define PORT 3490
#define MAXDATASIZE 1000
int main(int argc, char *argv[])
{
int sockfd, numbytes;
char buf[MAXDATASIZE];
struct hostent *he;
struct sockaddr_in their_addr;
if (argc != 2) {
fprintf(stderr,"usage: client hostname\n");
exit(1);
}
if ((he=gethostbyname(argv[1])) == NULL) { // get the host
info
perror("gethostbyname");
exit(1);
}
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
perror("socket");
exit(1);
}
their_addr.sin_family = AF_INET;
their_addr.sin_port = htons(PORT);
their_addr.sin_addr = *((struct in_addr *)he->h_addr);
memset(&(their_addr.sin_zero), '\0', 8);
if (connect(sockfd, (struct sockaddr *)&their_addr,
sizeof(struct sockaddr))
== -1) {
perror("connect");
exit(1);
}
if ((numbytes=recv(sockfd, buf, MAXDATASIZE-1, 0)) == -1) {
perror("recv");
exit(1);
}
buf[numbytes] = '\0';
printf("Received: %s\n",buf);
close(sockfd);
return 0;
}
===
it dosent allways return gibbarish, this is how the result looks like
when sys_info() is passed to send() as a message.
when i put the code of the function directly into main() and removed
the function sys_info(), it worked fine with these results
Im sure its obvious but im not that good in C, so if anyone can help
please do.
thanks
programming, i used send() to send the text, the text i used to send
is a result of a function, the problem is the other side recieves
gibbarish, here are server.c and client.c
------------
server.c
------------
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/wait.h>
#include <signal.h>
#include <sys/utsname.h>
#define MYPORT 3490
#define BACKLOG 10
char *sys_info() //the function returns version of system
{
char *computer=malloc(255*sizeof(char)), *rv=NULL;
struct utsname uts;
if(gethostname(computer, 255) != 0 || uname(&uts) < 0){
fprintf(stderr,"couldnt get host info");
free(computer);
exit(1);
}
rv=uts.version;
return rv;
}
void sigchld_handler(int s)
{
while(wait(NULL) > 0);
}
int main(void)
{
int sockfd, new_fd;
struct sockaddr_in my_addr;
struct sockaddr_in their_addr;
int sin_size;
struct sigaction sa;
int yes=1;
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
perror("socket");
exit(1);
}
if (setsockopt(sockfd,SOL_SOCKET,SO_REUSEADDR,&yes,sizeof(int))
== -1) {
perror("setsockopt");
exit(1);
}
my_addr.sin_family = AF_INET;
my_addr.sin_port = htons(MYPORT);
my_addr.sin_addr.s_addr = INADDR_ANY;
memset(&(my_addr.sin_zero), '\0', 8);
if (bind(sockfd, (struct sockaddr *)&my_addr, sizeof(struct
sockaddr))
== -1) {
perror("bind");
exit(1);
}
if (listen(sockfd, BACKLOG) == -1) {
perror("listen");
exit(1);
}
sa.sa_handler = sigchld_handler; // reap all dead processes
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART;
if (sigaction(SIGCHLD, &sa, NULL) == -1) {
perror("sigaction");
exit(1);
}
while(1) { // main accept() loop
sin_size = sizeof(struct sockaddr_in);
if ((new_fd = accept(sockfd, (struct sockaddr
*)&their_addr,&sin_size)) == -1) {
perror("accept");
continue;
}
printf("server: got connection from %s\n",
inet_ntoa(their_addr.sin_addr));
if (!fork()) {
close(sockfd);
if (send(new_fd, sys_info(), strlen(sys_info()), 0) ==
-1)// this is where i pass the result of the function sys_info() to
send()
perror("ERROR SENDING THE MESSAGE");
close(new_fd);
exit(0);
}
close(new_fd);
}
return 0;
}
-----------
client.c
-----------
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#define PORT 3490
#define MAXDATASIZE 1000
int main(int argc, char *argv[])
{
int sockfd, numbytes;
char buf[MAXDATASIZE];
struct hostent *he;
struct sockaddr_in their_addr;
if (argc != 2) {
fprintf(stderr,"usage: client hostname\n");
exit(1);
}
if ((he=gethostbyname(argv[1])) == NULL) { // get the host
info
perror("gethostbyname");
exit(1);
}
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
perror("socket");
exit(1);
}
their_addr.sin_family = AF_INET;
their_addr.sin_port = htons(PORT);
their_addr.sin_addr = *((struct in_addr *)he->h_addr);
memset(&(their_addr.sin_zero), '\0', 8);
if (connect(sockfd, (struct sockaddr *)&their_addr,
sizeof(struct sockaddr))
== -1) {
perror("connect");
exit(1);
}
if ((numbytes=recv(sockfd, buf, MAXDATASIZE-1, 0)) == -1) {
perror("recv");
exit(1);
}
buf[numbytes] = '\0';
printf("Received: %s\n",buf);
close(sockfd);
return 0;
}
===
it dosent allways return gibbarish, this is how the result looks like
when sys_info() is passed to send() as a message.
Received: #2 SM°Ôÿ¿i Feb 20 18:
when i put the code of the function directly into main() and removed
the function sys_info(), it worked fine with these results
Received: #2 SMP Fri Feb 20 18:11:42 GMT 2004
Im sure its obvious but im not that good in C, so if anyone can help
please do.
thanks