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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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
networking/udhcp/common.h
View File

@ -300,8 +300,8 @@ int udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt,
uint32_t dest_nip, int dest_port) FAST_FUNC; uint32_t dest_nip, int dest_port) FAST_FUNC;
void udhcp_sp_setup(void) FAST_FUNC; void udhcp_sp_setup(void) FAST_FUNC;
int udhcp_sp_fd_set(fd_set *rfds, int extra_fd) FAST_FUNC; void udhcp_sp_fd_set(struct pollfd *pfds, int extra_fd) FAST_FUNC;
int udhcp_sp_read(const fd_set *rfds) FAST_FUNC; int udhcp_sp_read(struct pollfd *pfds) FAST_FUNC;
int udhcp_read_interface(const char *interface, int *ifindex, uint32_t *nip, uint8_t *mac) FAST_FUNC; int udhcp_read_interface(const char *interface, int *ifindex, uint32_t *nip, uint8_t *mac) FAST_FUNC;

26
networking/udhcp/d6_dhcpc.c
View File

@ -935,9 +935,7 @@ int udhcpc6_main(int argc UNUSED_PARAM, char **argv)
int timeout; /* must be signed */ int timeout; /* must be signed */
unsigned already_waited_sec; unsigned already_waited_sec;
unsigned opt; unsigned opt;
int max_fd;
int retval; int retval;
fd_set rfds;
setup_common_bufsiz(); setup_common_bufsiz();
@ -1063,7 +1061,8 @@ int udhcpc6_main(int argc UNUSED_PARAM, char **argv)
* "continue" statements in code below jump to the top of the loop. * "continue" statements in code below jump to the top of the loop.
*/ */
for (;;) { for (;;) {
struct timeval tv; int tv;
struct pollfd pfds[2];
struct d6_packet packet; struct d6_packet packet;
uint8_t *packet_end; uint8_t *packet_end;
/* silence "uninitialized!" warning */ /* silence "uninitialized!" warning */
@ -1078,16 +1077,15 @@ int udhcpc6_main(int argc UNUSED_PARAM, char **argv)
* to change_listen_mode(). Thus we open listen socket * to change_listen_mode(). Thus we open listen socket
* BEFORE we send renew request (see "case BOUND:"). */ * 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 = timeout - already_waited_sec;
tv.tv_usec = 0;
retval = 0; retval = 0;
/* If we already timed out, fall through with retval = 0, else... */ /* If we already timed out, fall through with retval = 0, else... */
if ((int)tv.tv_sec > 0) { if (tv > 0) {
log1("waiting on select %u seconds", (int)tv.tv_sec); log1("waiting on select %u seconds", tv);
timestamp_before_wait = (unsigned)monotonic_sec(); timestamp_before_wait = (unsigned)monotonic_sec();
retval = select(max_fd + 1, &rfds, NULL, NULL, &tv); retval = poll(pfds, 2, tv * 1000);
if (retval < 0) { if (retval < 0) {
/* EINTR? A signal was caught, don't panic */ /* EINTR? A signal was caught, don't panic */
if (errno == EINTR) { if (errno == EINTR) {
@ -1222,8 +1220,8 @@ int udhcpc6_main(int argc UNUSED_PARAM, char **argv)
/* select() didn't timeout, something happened */ /* select() didn't timeout, something happened */
/* Is it a signal? */ /* Is it a signal? */
/* note: udhcp_sp_read checks FD_ISSET before reading */ /* note: udhcp_sp_read checks poll result before reading */
switch (udhcp_sp_read(&rfds)) { switch (udhcp_sp_read(pfds)) {
case SIGUSR1: case SIGUSR1:
client_config.first_secs = 0; /* make secs field count from 0 */ client_config.first_secs = 0; /* make secs field count from 0 */
already_waited_sec = 0; already_waited_sec = 0;
@ -1258,7 +1256,7 @@ int udhcpc6_main(int argc UNUSED_PARAM, char **argv)
} }
/* Is it a packet? */ /* Is it a packet? */
if (listen_mode == LISTEN_NONE || !FD_ISSET(sockfd, &rfds)) if (listen_mode == LISTEN_NONE || !pfds[1].revents)
continue; /* no */ continue; /* no */
{ {
@ -1460,8 +1458,8 @@ int udhcpc6_main(int argc UNUSED_PARAM, char **argv)
if (lease_seconds < 0x10) if (lease_seconds < 0x10)
lease_seconds = 0x10; lease_seconds = 0x10;
/// TODO: check for 0 lease time? /// TODO: check for 0 lease time?
if (lease_seconds >= 0x10000000) if (lease_seconds > 0x7fffffff / 1000)
lease_seconds = 0x0fffffff; lease_seconds = 0x7fffffff / 1000;
/* enter bound state */ /* enter bound state */
timeout = lease_seconds / 2; timeout = lease_seconds / 2;
bb_error_msg("lease obtained, lease time %u", bb_error_msg("lease obtained, lease time %u",

26
networking/udhcp/dhcpc.c
View File

@ -1281,9 +1281,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
unsigned already_waited_sec; unsigned already_waited_sec;
unsigned opt; unsigned opt;
IF_FEATURE_UDHCPC_ARPING(unsigned arpping_ms;) IF_FEATURE_UDHCPC_ARPING(unsigned arpping_ms;)
int max_fd;
int retval; int retval;
fd_set rfds;
setup_common_bufsiz(); 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. * "continue" statements in code below jump to the top of the loop.
*/ */
for (;;) { for (;;) {
struct timeval tv; int tv;
struct pollfd pfds[2];
struct dhcp_packet packet; struct dhcp_packet packet;
/* silence "uninitialized!" warning */ /* silence "uninitialized!" warning */
unsigned timestamp_before_wait = timestamp_before_wait; 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 * to change_listen_mode(). Thus we open listen socket
* BEFORE we send renew request (see "case BOUND:"). */ * 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 = timeout - already_waited_sec;
tv.tv_usec = 0;
retval = 0; retval = 0;
/* If we already timed out, fall through with retval = 0, else... */ /* If we already timed out, fall through with retval = 0, else... */
if ((int)tv.tv_sec > 0) { if (tv > 0) {
log1("waiting on select %u seconds", (int)tv.tv_sec); log1("waiting on select %u seconds", tv);
timestamp_before_wait = (unsigned)monotonic_sec(); timestamp_before_wait = (unsigned)monotonic_sec();
retval = select(max_fd + 1, &rfds, NULL, NULL, &tv); retval = poll(pfds, 2, tv * 1000);
if (retval < 0) { if (retval < 0) {
/* EINTR? A signal was caught, don't panic */ /* EINTR? A signal was caught, don't panic */
if (errno == EINTR) { if (errno == EINTR) {
@ -1591,8 +1589,8 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
/* select() didn't timeout, something happened */ /* select() didn't timeout, something happened */
/* Is it a signal? */ /* Is it a signal? */
/* note: udhcp_sp_read checks FD_ISSET before reading */ /* note: udhcp_sp_read checks poll result before reading */
switch (udhcp_sp_read(&rfds)) { switch (udhcp_sp_read(pfds)) {
case SIGUSR1: case SIGUSR1:
client_config.first_secs = 0; /* make secs field count from 0 */ client_config.first_secs = 0; /* make secs field count from 0 */
already_waited_sec = 0; already_waited_sec = 0;
@ -1627,7 +1625,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
} }
/* Is it a packet? */ /* Is it a packet? */
if (listen_mode == LISTEN_NONE || !FD_ISSET(sockfd, &rfds)) if (listen_mode == LISTEN_NONE || !pfds[1].revents)
continue; /* no */ 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 */ /* paranoia: must not be too small and not prone to overflows */
if (lease_seconds < 0x10) if (lease_seconds < 0x10)
lease_seconds = 0x10; lease_seconds = 0x10;
if (lease_seconds >= 0x10000000) if (lease_seconds > 0x7fffffff / 1000)
lease_seconds = 0x0fffffff; lease_seconds = 0x7fffffff / 1000;
} }
#if ENABLE_FEATURE_UDHCPC_ARPING #if ENABLE_FEATURE_UDHCPC_ARPING
if (opt & OPT_a) { if (opt & OPT_a) {

21
networking/udhcp/dhcpd.c
View File

@ -794,7 +794,7 @@ static NOINLINE void send_inform(struct dhcp_packet *oldpacket)
int udhcpd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int udhcpd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int udhcpd_main(int argc UNUSED_PARAM, char **argv) int udhcpd_main(int argc UNUSED_PARAM, char **argv)
{ {
int server_socket = -1, retval, max_sock; int server_socket = -1, retval;
uint8_t *state; uint8_t *state;
unsigned timeout_end; unsigned timeout_end;
unsigned num_ips; unsigned num_ips;
@ -891,10 +891,10 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
continue_with_autotime: continue_with_autotime:
timeout_end = monotonic_sec() + server_config.auto_time; timeout_end = monotonic_sec() + server_config.auto_time;
while (1) { /* loop until universe collapses */ while (1) { /* loop until universe collapses */
fd_set rfds; struct pollfd pfds[2];
struct dhcp_packet packet; struct dhcp_packet packet;
int bytes; int bytes;
struct timeval tv; int tv;
uint8_t *server_id_opt; uint8_t *server_id_opt;
uint8_t *requested_ip_opt; uint8_t *requested_ip_opt;
uint32_t requested_nip = requested_nip; /* for compiler */ uint32_t requested_nip = requested_nip; /* for compiler */
@ -906,16 +906,11 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
server_config.interface); server_config.interface);
} }
max_sock = udhcp_sp_fd_set(&rfds, server_socket); udhcp_sp_fd_set(pfds, server_socket);
if (server_config.auto_time) { tv = timeout_end - monotonic_sec();
/* cast to signed is essential if tv_sec is wider than int */
tv.tv_sec = (int)(timeout_end - monotonic_sec());
tv.tv_usec = 0;
}
retval = 0; retval = 0;
if (!server_config.auto_time || tv.tv_sec > 0) { if (!server_config.auto_time || tv > 0) {
retval = select(max_sock + 1, &rfds, NULL, NULL, retval = poll(pfds, 2, server_config.auto_time ? tv * 1000 : -1);
server_config.auto_time ? &tv : NULL);
} }
if (retval == 0) { if (retval == 0) {
write_leases(); write_leases();
@ -926,7 +921,7 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
continue; continue;
} }
switch (udhcp_sp_read(&rfds)) { switch (udhcp_sp_read(pfds)) {
case SIGUSR1: case SIGUSR1:
bb_error_msg("received %s", "SIGUSR1"); bb_error_msg("received %s", "SIGUSR1");
write_leases(); write_leases();

21
networking/udhcp/signalpipe.c
View File

@ -48,28 +48,29 @@ void FAST_FUNC udhcp_sp_setup(void)
, signal_handler); , signal_handler);
} }
/* Quick little function to setup the rfds. Will return the /* Quick little function to setup the pfds.
* max_fd for use with select. Limited in that you can only pass * Limited in that you can only pass one extra fd.
* one extra fd */ */
int FAST_FUNC udhcp_sp_fd_set(fd_set *rfds, int extra_fd) void FAST_FUNC udhcp_sp_fd_set(struct pollfd pfds[2], int extra_fd)
{ {
FD_ZERO(rfds); pfds[0].fd = signal_pipe.rd;
FD_SET(signal_pipe.rd, rfds); pfds[0].events = POLLIN;
pfds[1].fd = -1;
if (extra_fd >= 0) { if (extra_fd >= 0) {
close_on_exec_on(extra_fd); close_on_exec_on(extra_fd);
FD_SET(extra_fd, rfds); pfds[1].fd = extra_fd;
pfds[1].events = POLLIN;
} }
return signal_pipe.rd > extra_fd ? signal_pipe.rd : extra_fd;
} }
/* Read a signal from the signal pipe. Returns 0 if there is /* Read a signal from the signal pipe. Returns 0 if there is
* no signal, -1 on error (and sets errno appropriately), and * no signal, -1 on error (and sets errno appropriately), and
* your signal on success */ * your signal on success */
int FAST_FUNC udhcp_sp_read(const fd_set *rfds) int FAST_FUNC udhcp_sp_read(struct pollfd pfds[2])
{ {
unsigned char sig; unsigned char sig;
if (!FD_ISSET(signal_pipe.rd, rfds)) if (!pfds[0].revents)
return 0; return 0;
if (safe_read(signal_pipe.rd, &sig, 1) != 1) if (safe_read(signal_pipe.rd, &sig, 1) != 1)