busybox/libbb/xconnect.c

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/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Connect to host at port using address resolution from getaddrinfo
*
*/
#include "libbb.h"
/* Return network byte ordered port number for a service.
* If "port" is a number use it as the port.
* If "port" is a name it is looked up in /etc/services, if it isnt found return
* default_port
*/
unsigned short bb_lookup_port(const char *port, const char *protocol, unsigned short default_port)
{
unsigned short port_nr = htons(default_port);
if (port) {
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char *endptr;
int old_errno;
long port_long;
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/* Since this is a lib function, we're not allowed to reset errno to 0.
* Doing so could break an app that is deferring checking of errno. */
old_errno = errno;
errno = 0;
port_long = strtol(port, &endptr, 10);
if (errno != 0 || *endptr!='\0' || endptr==port || port_long < 0 || port_long > 65535) {
struct servent *tserv = getservbyname(port, protocol);
if (tserv) {
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port_nr = tserv->s_port;
}
} else {
port_nr = htons(port_long);
}
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errno = old_errno;
}
return port_nr;
}
void bb_lookup_host(struct sockaddr_in *s_in, const char *host)
{
struct hostent *he;
memset(s_in, 0, sizeof(struct sockaddr_in));
s_in->sin_family = AF_INET;
he = xgethostbyname(host);
memcpy(&(s_in->sin_addr), he->h_addr_list[0], he->h_length);
}
void xconnect(int s, const struct sockaddr *s_addr, socklen_t addrlen)
{
if (connect(s, s_addr, addrlen) < 0) {
if (ENABLE_FEATURE_CLEAN_UP) close(s);
if (s_addr->sa_family == AF_INET)
bb_perror_msg_and_die("unable to connect to remote host (%s)",
inet_ntoa(((struct sockaddr_in *)s_addr)->sin_addr));
bb_perror_msg_and_die("unable to connect to remote host");
}
}
int xconnect_tcp_v4(struct sockaddr_in *s_addr)
{
int s = xsocket(AF_INET, SOCK_STREAM, 0);
xconnect(s, (struct sockaddr*) s_addr, sizeof(*s_addr));
return s;
}