libbb: make bb_lookup_port() abort on bad port names

Also, no need to preserve errno

function                                             old     new   delta
.rodata                                           104247  104241      -6
bb_lookup_port                                        97      83     -14
nc_main                                             1039    1018     -21
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-41)             Total: -41 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2021-09-09 22:00:44 +02:00
parent 82c5eb8e46
commit 7ab9cd2398
4 changed files with 10 additions and 22 deletions

View File

@@ -115,27 +115,19 @@ void FAST_FUNC xconnect(int s, const struct sockaddr *s_addr, socklen_t addrlen)
/* Return 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
* If "port" is a name it is looked up in /etc/services.
* if NULL, return default_port
*/
unsigned FAST_FUNC bb_lookup_port(const char *port, const char *protocol, unsigned default_port)
unsigned FAST_FUNC bb_lookup_port(const char *port, const char *protocol, unsigned port_nr)
{
unsigned port_nr = default_port;
if (port) {
int old_errno;
/* 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;
port_nr = bb_strtou(port, NULL, 10);
if (errno || port_nr > 65535) {
struct servent *tserv = getservbyname(port, protocol);
port_nr = default_port;
if (tserv)
port_nr = ntohs(tserv->s_port);
//FIXME: else: port string was garbage, but we don't report that???
if (!tserv)
bb_error_msg_and_die("bad port '%s'", port);
port_nr = ntohs(tserv->s_port);
}
errno = old_errno;
}
return (uint16_t)port_nr;
}