/*++ /* NAME /* upass_connect 3 /* SUMMARY /* connect to UNIX-domain file descriptor listener /* SYNOPSIS /* #include <connect.h> /* /* int upass_connect(addr, block_mode, timeout) /* const char *addr; /* int block_mode; /* int timeout; /* DESCRIPTION /* upass_connect() connects to a file descriptor listener in /* the UNIX domain at the specified address, sends one half /* of a socketpair to the listener, and returns the other half /* to the caller. /* /* The file descriptor transporting connection is closed by /* a background thread. Some kernels might otherwise discard /* the descriptor before the server has received it. /* /* Arguments: /* .IP addr /* Null-terminated string with connection destination. /* .IP block_mode /* Either NON_BLOCKING for a non-blocking socket, or BLOCKING for /* blocking mode. This setting has no effect on the connection /* establishment process. /* .IP timeout /* Bounds the number of seconds that the operation may take. Specify /* a value <= 0 to disable the time limit. /* DIAGNOSTICS /* The result is -1 in case the connection could not be made. /* Fatal errors: other system call failures. /* LICENSE /* .ad /* .fi /* The Secure Mailer license must be distributed with this software. /* AUTHOR(S) /* Wietse Venema /* IBM T.J. Watson Research /* P.O. Box 704 /* Yorktown Heights, NY 10598, USA /*--*/ /* System interfaces. */ #include <sys_defs.h> #include <sys/socket.h> #include <sys/un.h> #include <string.h> #include <unistd.h> #include <errno.h> /* Utility library. */ #include <msg.h> #include <iostuff.h> #include <sane_connect.h> #include <connect.h> #include <timed_connect.h> #include <events.h> #include <mymalloc.h> #include <sane_socketpair.h> /* * Workaround for hostile kernels that don't support graceful shutdown. */ struct upass_connect { int fd; char *service; }; /* upass_connect_event - disconnect from peer */ static void upass_connect_event(int event, char *context) { struct upass_connect *up = (struct upass_connect *) context; static const char *myname = "upass_connect_event"; /* * Disconnect. */ if (event == EVENT_TIME) msg_warn("%s: read timeout for service %s", myname, up->service); event_disable_readwrite(up->fd); event_cancel_timer(upass_connect_event, context); if (close(up->fd) < 0) msg_warn("%s: close %s: %m", myname, up->service); myfree(up->service); myfree((char *) up); } /* upass_connect - connect to UNIX-domain file descriptor listener */ int upass_connect(const char *addr, int block_mode, int timeout) { struct upass_connect *up; int pair[2]; int sock; /* * Connect. */ if ((sock = unix_connect(addr, BLOCKING, timeout)) < 0) return (-1); /* * Send one socket pair half to the server. */ #define OUR_HALF 0 #define THEIR_HALF 1 if (sane_socketpair(AF_UNIX, SOCK_STREAM, 0, pair) < 0) { close(sock); return (-1); } if (unix_send_fd(sock, pair[THEIR_HALF]) < 0) { close(pair[THEIR_HALF]); close(pair[OUR_HALF]); close(sock); return (-1); } close(pair[THEIR_HALF]); /* * Return the other socket pair half to the caller. Don't close the * control socket just yet, but wait until the receiver closes it first. * Otherwise, some hostile kernel might discard the socket that we just * sent. */ up = (struct upass_connect *) mymalloc(sizeof(*up)); up->fd = sock; up->service = mystrdup(addr); if (timeout > 0) event_request_timer(upass_connect_event, (char *) up, timeout + 100); event_enable_read(sock, upass_connect_event, (char *) up); non_blocking(pair[OUR_HALF], block_mode); return (pair[OUR_HALF]); }