Unix invalid argument связка ключей

Socket, accept() function, Invalid argument

I am getting an error «Invalid argument» when i call the accept() on the server side of a client-server application. I don’t get what is wrong and if you see what is wrong let me know please. Thanks.

#include <stdio.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> int main(int argc, char* argv[]) { int sockfd, newsockfd, portno, len; struct sockaddr_in server, client; if(argc < 2){ perror(«Add more arguments»); } sockfd = socket(AF_UNIX,SOCK_STREAM,0); if(sockfd < 0){ perror(«Error at socket()»); } f(«Socketfd: %dn»,sockfd); bzero((char *)&server, sizeof(server)); portno = atoi(argv[1]); server.sin_family = AF_UNIX; server.sin_addr.s_addr = INADDR_ANY; server.sin_port = htons(portno); if(bind (sockfd, (struct sockaddr *)&server, sizeof(server)) <0){ perror(«Error at bind ()-server»); } listen(sockfd,5); int readval; char buffer[256]; for(;;){ len = sizeof(client); newsockfd = accept (sockfd, (struct sockaddr *)&server,&len); if (newsockfd == -1){ perror(«Erroare at accept()»); } else do{ readval = (sockfd,buffer,sizeof(buffer)); if (readval < 0 ){ perror(«Error at reading()»); } else if (readval == 0){ f(«End conection»); } else{ f(«Mesage is: %sn», buffer); } }while (readval > 0); close(newsockfd); } return 0; }

simonc

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asked Jan 14 ’13 at 11:42

Dimofte AlexDimofte Alex

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4

You have to use sockaddr_un instead of sockaddr_in for Unix domain sockets OR substitute AF_UNIX with AF_INET.

Plus, check the return of listen.

Plus change this line

readval = (sockfd,buffer,sizeof(buffer));

with

readval = read(newsockfd,buffer,sizeof(buffer));

because data is going to be sent through the newly created socket and not on the listening one

Plus, as mentioned by @trojanfoe, subst the server with the client structure into the accept() call

answered Jan 14 ’13 at 12:02

Davide BerraDavide Berra

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This line:

newsockfd = accept (sockfd, (struct sockaddr *)&server, &len);

Should be:

newsockfd = accept (sockfd, (struct sockaddr *)&client, &len);

From the manpage:

The argument addr is a pointer to a sockaddr structure. This structure is filled in with the address of the peer socket, as known to the communications layer. The exact format of the address returned addr is determined by the socket’s address family (see socket(2) and the respective protocol man pages). When addr is NULL, nothing is filled in; in this case, addrlen is not used, and should also be NULL.

Also check the return value from listen().

answered Jan 14 ’13 at 11:50

trojanfoetrojanfoe

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2

I ran into a similar issue before and it was due to not having the read in a loop. Here is an example I did before.

while (1) { new_sockfd = accept(sockfd, (struct sockaddr *) &client_addr, &sin_size); if (new_sockfd == -1) perror(«accepting connection»); f(«server: got connection from %s port %dn», inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port)); recv_length = recv(new_sockfd, &buffer, DATA, 0); while (recv_length > 0) { f(«RECV: %d bytesn», recv_length); dump(buffer, recv_length); recv_length = recv(new_sockfd, &buffer, DATA, 0); } close(new_sockfd); }

answered Jan 19 ’16 at 19:16

jarrjarr

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