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udhcp: use poll() instead of select()

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function                                             old     new   delta
udhcp_sp_read                                         65      46     -19
udhcp_sp_fd_set                                       79      54     -25
udhcpd_main                                         1530    1482     -48
udhcpc_main                                         2780    2730     -50
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/4 up/down: 0/-142)           Total: -142 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2017-02-16 23:25:44 +01:00
parent dc207f6696
commit 52a515d187
5 changed files with 45 additions and 53 deletions
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26
networking/udhcp/dhcpc.c
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@ -1281,9 +1281,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
unsigned already_waited_sec;
unsigned opt;
IF_FEATURE_UDHCPC_ARPING(unsigned arpping_ms;)
int max_fd;
int retval;
fd_set rfds;
setup_common_bufsiz();
@ -1432,7 +1430,8 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
* "continue" statements in code below jump to the top of the loop.
*/
for (;;) {
struct timeval tv;
int tv;
struct pollfd pfds[2];
struct dhcp_packet packet;
/* silence "uninitialized!" warning */
unsigned timestamp_before_wait = timestamp_before_wait;
@ -1446,16 +1445,15 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
* to change_listen_mode(). Thus we open listen socket
* BEFORE we send renew request (see "case BOUND:"). */
max_fd = udhcp_sp_fd_set(&rfds, sockfd);
udhcp_sp_fd_set(pfds, sockfd);
tv.tv_sec = timeout - already_waited_sec;
tv.tv_usec = 0;
tv = timeout - already_waited_sec;
retval = 0;
/* If we already timed out, fall through with retval = 0, else... */
if ((int)tv.tv_sec > 0) {
log1("waiting on select %u seconds", (int)tv.tv_sec);
if (tv > 0) {
log1("waiting on select %u seconds", tv);
timestamp_before_wait = (unsigned)monotonic_sec();
retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
retval = poll(pfds, 2, tv * 1000);
if (retval < 0) {
/* EINTR? A signal was caught, don't panic */
if (errno == EINTR) {
@ -1591,8 +1589,8 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
/* select() didn't timeout, something happened */
/* Is it a signal? */
/* note: udhcp_sp_read checks FD_ISSET before reading */
switch (udhcp_sp_read(&rfds)) {
/* note: udhcp_sp_read checks poll result before reading */
switch (udhcp_sp_read(pfds)) {
case SIGUSR1:
client_config.first_secs = 0; /* make secs field count from 0 */
already_waited_sec = 0;
@ -1627,7 +1625,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
}
/* Is it a packet? */
if (listen_mode == LISTEN_NONE || !FD_ISSET(sockfd, &rfds))
if (listen_mode == LISTEN_NONE || !pfds[1].revents)
continue; /* no */
{
@ -1742,8 +1740,8 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
/* paranoia: must not be too small and not prone to overflows */
if (lease_seconds < 0x10)
lease_seconds = 0x10;
if (lease_seconds >= 0x10000000)
lease_seconds = 0x0fffffff;
if (lease_seconds > 0x7fffffff / 1000)
lease_seconds = 0x7fffffff / 1000;
}
#if ENABLE_FEATURE_UDHCPC_ARPING
if (opt & OPT_a) {