[英]Why does using a file descriptor of the family AF_UNIX cause accept() to give an “invalid argument” error?
This is giving me an invalid argument error: 这给了我一个无效的参数错误:
int listenfd = socket(AF_UNIX, SOCK_STREAM, 0);
*clientfdp = accept(listenfd, (SA *) &clientAddr, &clientLen);
while this does not 虽然这不是
int listenfd = socket(AF_INET, SOCK_STREAM, 0);
*clientfdp = accept(listenfd, (SA *) &clientAddr, &clientLen);
But I need it to be AF_UNIX
. 但是我需要它是AF_UNIX
。 Whats the deal? 这是怎么回事? I have checked the errors everywhere as well. 我也检查了所有地方的错误。 The output of socket()
is fine in either case, it is just during the accept
. 无论哪种情况, socket()
的输出都很好,它只是在accept
期间。
Here is the code in its entirety: 以下是完整的代码:
// forward declarations
int error_msg( char * msg );
int usage( char name[] );
// a function to be executed by each thread
void * recv_log_msgs( void * arg );
// globals
FILE * log_fd; // opened by main() but accessible by each thread
typedef struct sockaddr SA;
int error_msg( char * msg )
{
printf( "%s\n", msg );
return -1;
}
void * recv_log_msgs( void * arg ) //Thread Routine
{
// loops to receive messages from a client;
// when the connection is closed by the client,
// close the socket
int clientfd = *((int *)arg);
char buffer[1500];
memset(buffer, 0, 1500);
int currentPos = 0;
int bytesRec;
int recvng = 1;
while(recvng){
bytesRec = recv(clientfd, buffer, 1500-currentPos, 0);
currentPos += bytesRec;
if(buffer[currentPos - 1] == '\n')
recvng = 0;
}
fprintf(log_fd, "LOGGER %d %s", clientfd, buffer);
close(clientfd);
return NULL;
}
int usage( char name[] )
{
printf( "Usage:\n" );
printf( "\t%s <log-file-name> <UDS path>\n", name );
return 1;
}
int main( int argc, char * argv[] )
{
if ( argc != 3 )
return usage( argv[0] );
log_fd = fopen(argv[1], "a");
// create a server socket
// domain (i.e., family) is AF_UNIX
// type is SOCK_STREAM
socklen_t clientLength = sizeof(struct sockaddr_un);
struct sockaddr_un clientAddr;
clientAddr.sun_family = AF_UNIX;
strcpy(clientAddr.sun_path, argv[2]);
pthread_t tid;
int listenfd = socket(AF_UNIX, SOCK_STREAM, 0);
// unlink the UDS path)
unlink(argv[2]);
// bind the server socket
bind(listenfd, (SA *)&clientAddr, clientLength);
// listen
listen(listenfd, 1024);
// loop to wait for connections;
// as each connection is accepted,
// launch a new thread that calls
// recv_log_msgs(), which receives
// messages and writes them to the log file
while(1){
printf( "Waiting for a connection on UDS path %s...\n", argv[2] );
int * clientfdp = malloc(sizeof(int));
*clientfdp = accept(listenfd, (SA *) &clientAddr, &clientLength);
pthread_create(&tid, NULL, recv_log_msgs, clientfdp);
printf("%d",errno);
return 0;
}
// when the loop ends, close the listening socket
close(listenfd);
// close the log file
fclose(log_fd);
return 0;
}
the main() function fails to call pthread_join()
after calling pthread_create()
main()函数在调用pthread_join()
后无法调用pthread_create()
The result is the process exits before the thread has a chance to write anything to the log file. 结果是进程在线程有机会将任何内容写入日志文件之前退出。
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