From: Florian Forster Date: Sat, 2 Dec 2006 15:30:38 +0000 (+0100) Subject: dns plugin: Use threads rather than two processes and a pipe. X-Git-Tag: collectd-3.11.0~39^2~4 X-Git-Url: https://git.tokkee.org/?a=commitdiff_plain;h=ea30b35a3697a7f8c126c35b62653593c08de63c;p=collectd.git dns plugin: Use threads rather than two processes and a pipe. This is not only much simpler, code wise, but also more elegant and hopefully faster. This code is alpha quality at best. --- diff --git a/src/dns.c b/src/dns.c index b97ce287..da45a389 100644 --- a/src/dns.c +++ b/src/dns.c @@ -26,6 +26,10 @@ #include "configfile.h" #include "utils_debug.h" +#if HAVE_PTHREAD_H +# include +#endif + #if HAVE_SYS_POLL_H # include #endif @@ -38,7 +42,7 @@ # define NAMED_HAVE_CONFIG 0 #endif -#if HAVE_LIBPCAP +#if HAVE_LIBPCAP && HAVE_PTHREAD_H # include "utils_dns.h" # define NAMED_HAVE_READ 1 #else @@ -88,6 +92,7 @@ static char *rcode_ds_def[] = }; static int rcode_ds_num = 1; +/* FIXME: Wouldn't other defines be better? -octo */ #if NAMED_HAVE_CONFIG #if HAVE_LIBPCAP static char *config_keys[] = @@ -103,7 +108,6 @@ static int config_keys_num = 2; #if HAVE_LIBPCAP #define PCAP_SNAPLEN 1460 static char *pcap_device = NULL; -static int pipe_fd = -1; static unsigned int tr_queries; static unsigned int tr_responses; @@ -112,6 +116,16 @@ static counter_list_t *opcode_list; static counter_list_t *rcode_list; #endif +#if HAVE_PTHREAD_H +static pthread_t listen_thread; +static int listen_thread_init = 0; +/* The `traffic' mutex if for `tr_queries' and `tr_responses' */ +static pthread_mutex_t traffic_mutex = PTHREAD_MUTEX_INITIALIZER; +static pthread_mutex_t qtype_mutex = PTHREAD_MUTEX_INITIALIZER; +static pthread_mutex_t opcode_mutex = PTHREAD_MUTEX_INITIALIZER; +static pthread_mutex_t rcode_mutex = PTHREAD_MUTEX_INITIALIZER; +#endif + static counter_list_t *counter_list_search (counter_list_t **list, unsigned int key) { counter_list_t *entry; @@ -183,50 +197,6 @@ static void counter_list_add (counter_list_t **list, DBG ("return ()"); } -static int counter_list_send (counter_list_t *list, int fd) -{ - counter_list_t *cl; - unsigned int values[2 * T_MAX]; - unsigned int values_num; - - if (fd < 0) - return (-1); - - values_num = 0; - - for (cl = list; - (cl != NULL) && (values_num < T_MAX); - cl = cl->next) - { - values[2 * values_num] = cl->key; - values[(2 * values_num) + 1] = cl->value; - values_num++; - } - - DBG ("swrite (fd = %i, values_num = %i)", fd, values_num); - if (swrite (fd, (const void *) &values_num, sizeof (values_num)) != 0) - { - DBG ("Writing to fd failed: %s", strerror (errno)); - syslog (LOG_ERR, "dns plugin: Writing to fd failed: %s", - strerror (errno)); - return (-1); - } - - if (values_num == 0) - return (0); - - DBG ("swrite (fd = %i, values = %p, size = %i)", - fd, (void *) values, (int) (sizeof (int) * values_num)); - if (swrite (fd, (const void *) values, 2 * sizeof (int) * values_num) != 0) - { - DBG ("Writing to pipe failed: %s", strerror (errno)); - syslog (LOG_ERR, "dns plugin: Writing to pipe failed: %s", - strerror (errno)); - return (-1); - } - - return (values_num); -} #if NAMED_HAVE_CONFIG static int dns_config (char *key, char *value) { @@ -258,30 +228,43 @@ static void dns_child_callback (const rfc1035_header_t *dns) if (dns->qr == 0) { /* This is a query */ + pthread_mutex_lock (&traffic_mutex); tr_queries += dns->length; + pthread_mutex_unlock (&traffic_mutex); + + pthread_mutex_lock (&qtype_mutex); counter_list_add (&qtype_list, dns->qtype, 1); + pthread_mutex_unlock (&qtype_mutex); } else { /* This is a reply */ + pthread_mutex_lock (&traffic_mutex); tr_responses += dns->length; + pthread_mutex_unlock (&traffic_mutex); + + pthread_mutex_lock (&rcode_mutex); counter_list_add (&rcode_list, dns->rcode, 1); + pthread_mutex_unlock (&rcode_mutex); } /* FIXME: Are queries, replies or both interesting? */ + pthread_mutex_lock (&opcode_mutex); counter_list_add (&opcode_list, dns->opcode, 1); + pthread_mutex_unlock (&opcode_mutex); } -static void dns_child_loop (void) +static void *dns_child_loop (void *dummy) { pcap_t *pcap_obj; char pcap_error[PCAP_ERRBUF_SIZE]; struct bpf_program fp; - struct pollfd poll_fds[2]; + struct pollfd poll_fds[1]; int status; /* Don't catch these signals */ + /* FIXME: Really? */ signal (SIGINT, SIG_DFL); signal (SIGTERM, SIG_DFL); @@ -294,12 +277,11 @@ static void dns_child_loop (void) pcap_error); if (pcap_obj == NULL) { - syslog (LOG_ERR, "dns plugin: Opening interface `%s' failed: %s", + syslog (LOG_ERR, "dns plugin: Opening interface `%s' " + "failed: %s", (pcap_device != NULL) ? pcap_device : "any", pcap_error); - close (pipe_fd); - pipe_fd = -1; - return; + return (NULL); } memset (&fp, 0, sizeof (fp)); @@ -307,17 +289,13 @@ static void dns_child_loop (void) { DBG ("pcap_compile failed"); syslog (LOG_ERR, "dns plugin: pcap_compile failed"); - close (pipe_fd); - pipe_fd = -1; - return; + return (NULL); } if (pcap_setfilter (pcap_obj, &fp) < 0) { DBG ("pcap_setfilter failed"); syslog (LOG_ERR, "dns plugin: pcap_setfilter failed"); - close (pipe_fd); - pipe_fd = -1; - return; + return (NULL); } DBG ("PCAP object created."); @@ -325,18 +303,14 @@ static void dns_child_loop (void) dnstop_set_pcap_obj (pcap_obj); dnstop_set_callback (dns_child_callback); - /* Set up pipe end */ - poll_fds[0].fd = pipe_fd; - poll_fds[0].events = POLLOUT; + /* Set up poll object */ + poll_fds[0].fd = pcap_fileno (pcap_obj); + poll_fds[0].events = POLLIN | POLLPRI; - /* Set up pcap device */ - poll_fds[1].fd = pcap_fileno (pcap_obj); - poll_fds[1].events = POLLIN | POLLPRI; - - while (pipe_fd > 0) + while (42) { DBG ("poll (...)"); - status = poll (poll_fds, 2, -1 /* wait forever for a change */); + status = poll (poll_fds, 1, -1 /* wait forever for a change */); /* Signals are not caught, but this is very handy when * attaching to the process with a debugger. -octo */ @@ -354,45 +328,12 @@ static void dns_child_loop (void) } if (poll_fds[0].revents & (POLLERR | POLLHUP | POLLNVAL)) - { - DBG ("Pipe closed. Exiting."); - syslog (LOG_NOTICE, "dns plugin: Pipe closed. Exiting."); - break; - } - else if (poll_fds[0].revents & POLLOUT) - { - DBG ("Sending data.."); - - DBG ("swrite (pipe_fd = %i, tr_queries = %i)", pipe_fd, tr_queries); - if (swrite (pipe_fd, (const void *) &tr_queries, sizeof (tr_queries)) != 0) - { - DBG ("Writing to pipe_fd failed: %s", strerror (errno)); - syslog (LOG_ERR, "dns plugin: Writing to pipe_fd failed: %s", - strerror (errno)); - return; - } - - DBG ("swrite (pipe_fd = %i, tr_responses = %i)", pipe_fd, tr_responses); - if (swrite (pipe_fd, (const void *) &tr_responses, sizeof (tr_responses)) != 0) - { - DBG ("Writing to pipe_fd failed: %s", strerror (errno)); - syslog (LOG_ERR, "dns plugin: Writing to pipe_fd failed: %s", - strerror (errno)); - return; - } - - counter_list_send (qtype_list, pipe_fd); - counter_list_send (opcode_list, pipe_fd); - counter_list_send (rcode_list, pipe_fd); - } - - if (poll_fds[1].revents & (POLLERR | POLLHUP | POLLNVAL)) { DBG ("pcap-device closed. Exiting."); syslog (LOG_ERR, "dns plugin: pcap-device closed. Exiting."); break; } - else if (poll_fds[1].revents & (POLLIN | POLLPRI)) + else if (poll_fds[0].revents & (POLLIN | POLLPRI)) { status = pcap_dispatch (pcap_obj, 10 /* Only handle 10 packets at a time */, @@ -410,54 +351,38 @@ static void dns_child_loop (void) DBG ("child is exiting"); - close (pipe_fd); - pipe_fd = -1; pcap_close (pcap_obj); + pthread_exit (NULL); + + return (NULL); } /* static void dns_child_loop (void) */ static void dns_init (void) { #if HAVE_LIBPCAP - int pipe_fds[2]; - pid_t pid_child; +#if HAVE_PTHREAD_H + /* clean up an old thread */ + int status; + pthread_mutex_lock (&traffic_mutex); tr_queries = 0; tr_responses = 0; + pthread_mutex_unlock (&traffic_mutex); - if (pipe (pipe_fds) != 0) - { - syslog (LOG_ERR, "dns plugin: pipe(2) failed: %s", - strerror (errno)); + if (listen_thread_init != 0) return; - } - /* Fork off child */ - pid_child = fork (); - if (pid_child < 0) + status = pthread_create (&listen_thread, NULL, dns_child_loop, + (void *) 0); + if (status != 0) { - syslog (LOG_ERR, "dns plugin: fork(2) failed: %s", - strerror (errno)); - close (pipe_fds[0]); - close (pipe_fds[1]); + syslog (LOG_ERR, "dns plugin: pthread_create failed: %s", + strerror (status)); return; } - else if (pid_child != 0) - { - /* parent: Close the writing end, keep the reading end. */ - pipe_fd = pipe_fds[0]; - close (pipe_fds[1]); - } - else - { - /* child: Close the reading end, keep the writing end. */ - pipe_fd = pipe_fds[1]; - close (pipe_fds[0]); - - dns_child_loop (); - exit (0); - } - /* fcntl (pipe_fd, F_SETFL, O_NONBLOCK); */ + listen_thread_init = 1; +#endif #endif } @@ -570,94 +495,67 @@ static void opcode_submit (int opcode, unsigned int counter) } #if NAMED_HAVE_READ -static unsigned int dns_read_array (unsigned int *values) +static void dns_read (void) { - unsigned int values_num; - - if (pipe_fd < 0) - return (0); - - if (sread (pipe_fd, (void *) &values_num, sizeof (values_num)) != 0) - { - DBG ("Reading from the pipe failed: %s", - strerror (errno)); - syslog (LOG_ERR, "dns plugin: Reading from the pipe failed: %s", - strerror (errno)); - pipe_fd = -1; - return (0); - } - DBG ("sread (pipe_fd = %i, values_num = %u)", pipe_fd, values_num); + unsigned int keys[T_MAX]; + unsigned int values[T_MAX]; + int len; + int i; - assert (values_num <= T_MAX); + counter_list_t *ptr; - if (values_num == 0) - return (0); + pthread_mutex_lock (&traffic_mutex); + values[0] = tr_queries; + values[1] = tr_responses; + pthread_mutex_unlock (&traffic_mutex); + traffic_submit (values[0], values[1]); - if (sread (pipe_fd, (void *) values, 2 * sizeof (unsigned int) * values_num) != 0) + pthread_mutex_lock (&qtype_mutex); + for (ptr = qtype_list, len = 0; + (ptr != NULL) && (len < T_MAX); + ptr = ptr->next, len++) { - DBG ("Reading from the pipe failed: %s", - strerror (errno)); - syslog (LOG_ERR, "dns plugin: Reading from the pipe failed: %s", - strerror (errno)); - pipe_fd = -1; - return (0); + keys[len] = ptr->key; + values[len] = ptr->value; } + pthread_mutex_unlock (&qtype_mutex); - return (values_num); -} - -static void dns_read (void) -{ - unsigned int values[2 * T_MAX]; - unsigned int values_num; - int i; - - if (pipe_fd < 0) - return; - - if (sread (pipe_fd, (void *) &tr_queries, sizeof (tr_queries)) != 0) + for (i = 0; i < len; i++) { - DBG ("Reading from the pipe failed: %s", - strerror (errno)); - syslog (LOG_ERR, "dns plugin: Reading from the pipe failed: %s", - strerror (errno)); - pipe_fd = -1; - return; + DBG ("qtype = %u; counter = %u;", keys[i], values[i]); + qtype_submit (keys[i], values[i]); } - DBG ("sread (pipe_fd = %i, tr_queries = %u)", pipe_fd, tr_queries); - if (sread (pipe_fd, (void *) &tr_responses, sizeof (tr_responses)) != 0) + pthread_mutex_lock (&opcode_mutex); + for (ptr = opcode_list, len = 0; + (ptr != NULL) && (len < T_MAX); + ptr = ptr->next, len++) { - DBG ("Reading from the pipe failed: %s", - strerror (errno)); - syslog (LOG_ERR, "dns plugin: Reading from the pipe failed: %s", - strerror (errno)); - pipe_fd = -1; - return; + keys[len] = ptr->key; + values[len] = ptr->value; } - DBG ("sread (pipe_fd = %i, tr_responses = %u)", pipe_fd, tr_responses); - - traffic_submit (tr_queries, tr_responses); + pthread_mutex_unlock (&opcode_mutex); - values_num = dns_read_array (values); - for (i = 0; i < values_num; i++) + for (i = 0; i < len; i++) { - DBG ("qtype = %u; counter = %u;", values[2 * i], values[(2 * i) + 1]); - qtype_submit (values[2 * i], values[(2 * i) + 1]); + DBG ("opcode = %u; counter = %u;", keys[i], values[i]); + opcode_submit (keys[i], values[i]); } - values_num = dns_read_array (values); - for (i = 0; i < values_num; i++) + pthread_mutex_lock (&rcode_mutex); + for (ptr = rcode_list, len = 0; + (ptr != NULL) && (len < T_MAX); + ptr = ptr->next, len++) { - DBG ("opcode = %u; counter = %u;", values[2 * i], values[(2 * i) + 1]); - opcode_submit (values[2 * i], values[(2 * i) + 1]); + keys[len] = ptr->key; + values[len] = ptr->value; } + pthread_mutex_unlock (&rcode_mutex); - values_num = dns_read_array (values); - for (i = 0; i < values_num; i++) + for (i = 0; i < len; i++) { - DBG ("rcode = %u; counter = %u;", values[2 * i], values[(2 * i) + 1]); - rcode_submit (values[2 * i], values[(2 * i) + 1]); + DBG ("rcode = %u; counter = %u;", keys[i], values[i]); + rcode_submit (keys[i], values[i]); } } #else /* if !NAMED_HAVE_READ */