add serial/socket plugin example

Daemons/weatherdaemon_multimeteo/plugins/fdexample.c

@@ -0,0 +1,178 @@
+/*
+ * This file is part of the weatherdaemon project.
+ * Copyright 2026 Edward V. Emelianov <edward.emelianoff@gmail.com>.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <pthread.h>
+#include <signal.h> // pthread_kill
+#include <string.h>
+#include <time.h>
+#include <usefull_macros.h>
+
+#include "weathlib.h"
+
+// dummy example of file descriptors usage
+
+#define NS (4)
+
+static time_t Tpoll = 10;
+extern sensordata_t sensor;
+static int fdes = -1;
+static sl_ringbuffer_t *rb;
+static pthread_t thread;
+static void (*freshdatahandler)(const struct sensordata_t* const) = NULL;
+static void die();
+
+static val_t values[NS] = { // fields `name` and `comment` have no sense until value meaning is `IS_OTHER`
+    {.name = "WIND",     .sense = VAL_OBLIGATORY,  .type = VALT_FLOAT, .meaning = IS_WIND},
+    {.name = "EXTTEMP",  .sense = VAL_OBLIGATORY,  .type = VALT_FLOAT, .meaning = IS_AMB_TEMP},
+    {.name = "PRESSURE", .sense = VAL_RECOMMENDED, .type = VALT_FLOAT, .meaning = IS_PRESSURE},
+    {.name = "HUMIDITY", .sense = VAL_RECOMMENDED, .type = VALT_FLOAT, .meaning = IS_HUMIDITY},
+};
+
+static int format_values(char *buf){
+    int gotvals = 0;
+    char *token = strtok(buf, ",");
+    time_t tnow = time(NULL);
+    while(token && gotvals < NS){
+        double v;
+        DBG("TOKEN: %s", token);
+        if(sl_str2d(&v, token)){
+            DBG("next value: %g", v);
+            values[gotvals].value.f = (float) v;
+            values[gotvals].time = tnow;
+            ++gotvals;
+        }
+        token = strtok(NULL, ",");
+    }
+    DBG("GOT: %d", gotvals);
+    return gotvals;
+}
+
+static ssize_t writedata(int fd, const char *str, size_t size){
+    ssize_t sent = 0;
+    do{
+        DBG("try to write %zd bytes", size);
+        int canwrite = sl_canwrite(fd);
+        if(canwrite < 0){
+            WARNX("Disconnected?!");
+            return -1;
+        }else if(canwrite){
+            ssize_t r = write(fd, str+sent, size);
+            if(r < 0){
+                sent = -1;
+                WARNX("Disconnected??");
+                break;
+            }else{
+                sent += r;
+                size -= r;
+            }
+            DBG("sent %zd bytes; total send %zd, leave %zd", r, sent, size);
+        }
+    }while(size);
+    return sent;
+}
+
+static void *mainthread(void _U_ *U){
+    FNAME();
+    time_t task = 0;
+    const char begging[] = "Enter comma-separated data: wind, exttemp, pressure, humidity\n";
+    char buf[128];
+    while(fdes > -1){
+        time_t tnow = time(NULL);
+        int canread = sl_canread(fdes);
+        if(canread < 0){
+            WARNX("Disconnected fd %d", fdes);
+            break;
+        }else if(canread == 1){
+            ssize_t got = read(fdes, buf, 128);
+            if(got > 0){
+                sl_RB_write(rb, (uint8_t*)buf, got);
+            }else if(got < 0){
+                DBG("Disconnected?");
+                break;
+            }
+        }
+        if(sl_RB_readline(rb, buf, 127) > 0){
+            if(NS == format_values(buf) && freshdatahandler)
+                freshdatahandler(&sensor);
+        }
+        if(tnow >= task){
+            DBG("write %s", begging);
+            ssize_t got = writedata(fdes, begging, sizeof(begging)-1);
+            if(got > 0) task = tnow + Tpoll;
+            else if(got < 0){
+                close(fdes);
+                fdes = -1;
+            }
+        }
+    }
+    DBG("OOOOps!");
+    return NULL;
+}
+
+static int init(int N, time_t pollt, int fd){
+    FNAME();
+    if(!(rb = sl_RB_new(BUFSIZ))){
+        WARNX("Can't init ringbuffer!");
+        return 0;
+    }
+    if(pthread_create(&thread, NULL, mainthread, NULL)) return 0;
+    sensor.PluginNo = N;
+    if(pollt) Tpoll = pollt;
+    fdes = fd;
+    if(fdes < 0) return -1;
+    return NS;
+}
+
+static int onrefresh(void (*handler)(const struct sensordata_t* const)){
+    FNAME();
+    if(!handler) return FALSE;
+    freshdatahandler = handler;
+    return TRUE;
+}
+
+
+static int getval(val_t *o, int N){
+    if(N < 0 || N >= NS) return FALSE;
+    if(o) *o = values[N];
+    return TRUE;
+}
+
+static void die(){
+    FNAME();
+    if(0 == pthread_kill(thread, -9)){
+        DBG("Killed, join");
+        pthread_join(thread, NULL);
+        DBG("Done");
+    }
+    DBG("Delete RB");
+    sl_RB_delete(&rb);
+    if(fdes > -1){
+        close(fdes);
+        DBG("FD closed");
+    }
+    DBG("FDEXAMPLE: died");
+}
+
+sensordata_t sensor = {
+    .name = "Dummy socket or serial device weatherstation",
+    .Nvalues = NS,
+    .init = init,
+    .onrefresh = onrefresh,
+    .get_value = getval,
+    .die = die,
+};