add docs, make little fixes

Daemons/weather_logger/Readme.md

@@ -0,0 +1,127 @@
+# meteologger
+
+**meteologger** is a client that collects meteorological data from the
+[`weatherdaemon_multimeteo`](https://github.com/eddyem/small_tel/tree/master/Daemons/weatherdaemon_multimeteo)
+daemon. It connects to the daemon over a TCP or UNIX socket, periodically requests data from all
+available weather stations, and saves the received values into separate files (one per station).
+
+The project is written in C and uses the
+[`usefull_macros`](https://github.com/eddyem/snippets_library) library for socket handling,
+logging, argument parsing, and helper macros.
+
+## Repository
+
+Source code is located in the [small_tel](https://github.com/eddyem/small_tel) repository under
+`Daemons/weather_logger`.
+
+### Dependencies
+
+- Linux (uses Linux‑specific calls: `prctl`, `fork`, `waitpid`, signals)
+- CMake ≥ 4.0
+- C compiler (GCC, Clang)
+- `usefull_macros` library ≥ 0.3.5 (must be installed and discoverable via `pkg-config`)
+
+### Building
+
+```bash
+git clone --depth=1 https://github.com/eddyem/small_tel.git
+cd small_tel/Daemons/weather_logger
+mkdir build && cd build
+cmake ..    # or -DDEBUG=on for debug build
+make
+```
+
+The executable `meteologger` will be placed in `build/` (or `bin/` after installation).
+
+### Installation
+
+```bash
+su -c "make install"
+```
+
+By default the program is installed into `bin` (usually `/usr/local/bin`).
+
+## Usage
+
+```
+meteologger -n <node> -o <directory> [options]
+```
+
+### Required arguments
+
+| Option | Long form      | Description |
+|--------|----------------|-------------|
+| `-n`   | `--node`       | Node to connect to: `<host>:<port>` (e.g., `127.0.0.1:5555`) or a UNIX socket path when `-u` is given. |
+| `-o`   | `--output`     | Directory where database files will be stored (must exist and be writable). |
+
+### Optional arguments
+
+| Option | Long form      | Default                     | Description |
+|--------|----------------|-----------------------------|-------------|
+| `-h`   | `--help`       | -                           | Show help and exit. |
+| `-u`   | `--isunix`     | -                           | Use a UNIX socket instead of TCP. |
+| `-l`   | `--logfile`    | (none)                      | File to write logs |
+| `-p`   | `--pidfile`    | `/tmp/meteologger.pid`      | File where the process PID is written. |
+| `-v`   | `--verbose`    | 0                           | Increase logging verbosity (each `-v` raises the level). |
+| `-i`   | `--interval`   | `0.5`                       | Request interval in seconds. Allowed range: `[0.2, 900]`. |
+| `-t`   | `--timeout`    | `1.0`                       | Network timeout for server responses (seconds). Allowed range: `[0.1, 30]`. |
+
+### Examples
+
+1. Connect to a local daemon on port 5555 and store data in `/var/log/weather`:
+    ```bash
+    meteologger -n 127.0.0.1:5555 -o /var/log/weather
+    ```
+   
+2. Use a UNIX socket `/tmp/weather.sock`, write PID to `/run/meteologger.pid`:
+    ```bash
+    meteologger -n /tmp/weather.sock -o /data/weather -u -p /run/meteologger.pid
+    ```
+    
+3. Enable verbose logging to a file:
+    ```bash
+    meteologger -n localhost:5555 -o /srv/weather -vv -l /var/log/meteologger.log
+    ```
+
+## Output file format
+
+Files are stored in the directory given by `-o` and are named `weatherXX.log`, where `XX` is a
+two‑digit station number (from `00` to `99`). If a file already exists for a station (matching the
+station name in the header comment), new data is appended.
+
+File structure:
+
+```
+# <station_name>
+# Station #<number>, format: KEYWORD[level],...
+# TIMESTAMP, <key1>[<level1>], <key2>[<level2>], ...
+<timestamp>, <value1>, <value2>, ...
+```
+
+Example:
+
+```
+# WXA100-06 ultrasonic meteostation @ D:/dev/pl2303_0
+# Station #0, format: KEYWORD[level],...
+# TIMESTAMP, WIND[1], WINDDIR[2], HUMIDITY[1], EXTTEMP[1], PRESSURE[1], PRECIP[3], PRECIPLV[3], PRECRATE[3]
+1779369905, 0.50, 120.70, 76.90, 8.40, 590.00, 1, 374.70, 0.00
+1779369907, 0.60, 128.20, 76.90, 8.40, 590.00, 1, 374.70, 0.00
+1779369909, 0.70, 130.30, 76.90, 8.40, 590.00, 1, 374.70, 0.00
+...
+```
+
+- First line: comment with station name.
+- Second line: station number and format description.
+- Third line: column headers: `TIMESTAMP` followed by  keys with their levels.
+- Following lines: data – Unix timestamp (integer) and values (floating‑point, integer or string).
+
+-----
+
+## License
+
+Copyright © 2026 Edward V. Emelianov.
+**GNU General Public License v3.0** or later.
+
+See the `LICENSE` file in repository's root directory or [http://www.gnu.org/licenses/](http://www.gnu.org/licenses/)
+for details.
+

Daemons/weather_logger/main.c

@@ -79,6 +79,15 @@ int main(int argc, char **argv){
     signal(SIGUSR1, signals); // reload DB
 #ifndef EBUG
     if(sl_daemonize()) ERRX("Can't daemonize");
+#endif
+    if(G->logfile){
+        sl_loglevel_e lvl = LOGLEVEL_ERR + G->verb;
+        if(lvl >= LOGLEVEL_AMOUNT) lvl = LOGLEVEL_AMOUNT - 1;
+        DBG("Loglevel: %d", lvl);
+        OPENLOG(G->logfile, lvl, 1);
+    }
+    LOGMSG("Started");
+#ifndef EBUG
     catchsig = INT_MAX; // now `signals` won't run exit()
     while(catchsig == INT_MAX){ // guard for dead processes
         childpid = fork();
@@ -114,8 +123,10 @@ int main(int argc, char **argv){
     }else{
         pid_t self = getpid();
         prepare_and_run(G);
-        if(catchsig == INT_MAX) LOGERR("Child process %d died", self);
-        else LOGERR("Child process %d exits with status %d", self, catchsig);
+        if(catchsig == INT_MAX){
+            LOGERR("Child process %d died", self);
+            catchsig = 0; // like normal exit
+        }else LOGERR("Child process %d exits with status %d", self, catchsig);
         ; // cleanup child here
 #ifdef EBUG
         if(G->pidfile) unlink(G->pidfile); // unlink PID-file in debug-mode

Daemons/weather_logger/meteologger.files

@@ -1,4 +1,5 @@
 CMakeLists.txt
+Readme.md
 main.c
 parseargs.c
 parseargs.h

Daemons/weather_logger/parseargs.c

@@ -61,7 +61,7 @@ glob_pars *parseargs(int *argc, char ***argv){
     // remove trailing '/'
     int eol = strlen(G.bddir) - 1;
     DBG("eol=%d", eol);
-    while(eol > 0){
+    while(eol > 0){ // don't remove leading slash in case of "/"
         DBG("before: %s", G.bddir);
         if(G.bddir[eol] == '/') G.bddir[eol] = 0;
         else break;
@@ -73,10 +73,7 @@ glob_pars *parseargs(int *argc, char ***argv){
     if(G.net_timeout < MIN_NET_TMOUT || G.net_timeout > MAX_NET_TMOUT)
         ERRX("Wrong network timeout %g, should be in [%g, %g]", G.net_timeout, MIN_NET_TMOUT, MAX_NET_TMOUT);
     if(G.logfile){
-        sl_loglevel_e lvl = LOGLEVEL_ERR + G.verb;
-        if(lvl >= LOGLEVEL_AMOUNT) lvl = LOGLEVEL_AMOUNT - 1;
-        DBG("Loglevel: %d", lvl);
-        if(!OPENLOG(G.logfile, lvl, 1)) ERRX("Can't open log file %s", G.logfile);
+        if(*G.logfile != '/') ERRX("Logging file path should be absolute!");
     }
     return &G;
 }

Daemons/weather_logger/server.c

@@ -128,7 +128,15 @@ void set_nettimeout(double dt){
  */
 static bool write2fd(senslog_t *sensor, const char *str, size_t len){
     if(!sensor || !str || len < 1) return false;
-    if(write(sensor->fd, str, len) != (ssize_t)len){
+    const char *ptr = str;
+    size_t written = 0;
+    while(len){
+        ssize_t l = write(sensor->fd, ptr, len);
+        if(l < 0) break;
+        len -= l;
+        ptr += l;
+    }
+    if(written != len){
         LOGERR("Can't write '%s' to file %s: %s", str, sensor->path, strerror(errno));
         WARNX("Can't write data to file");
         close(sensor->fd);
@@ -405,8 +413,10 @@ static bool analyse_list(sl_sock_t *sock){
         if(Nsensors <= idx){
             int oldN = Nsensors;
             Nsensors = idx + 1;
+            senslog_t *old_sensors = sensors;
             sensors = realloc(sensors, Nsensors * sizeof(senslog_t));
             if(!sensors){
+                sensors = old_sensors; // restore old pointer instead of NULL
                 sensors_delete();
                 LOGERR("analyse_list(): error in realloc()");
                 WARNX("analyse_list(): error in realloc()");
@@ -545,8 +555,11 @@ static bool poll_server_answers(sl_sock_t *sock){
                     // now throw data to disk
                     DBG("throw '%s' with length %d to disk", sensor->buf, sensor->buflen);
                     allOK = write2fd(sensor, sensor->buf, sensor->buflen);
-                    write2fd(sensor, "\n", 1);
-                    sensor->lasttimestamp = ts;
+                    if(allOK){
+                        write2fd(sensor, "\n", 1);
+                        fsync(sensor->fd); // sync last full record
+                        sensor->lasttimestamp = ts;
+                    }
                     DBG("Data for %d is %swritten to disk", sensor->idx, allOK ? "" : "not ");
                 }
             }
@@ -596,8 +609,22 @@ static bool poll_server_answers(sl_sock_t *sock){
             }
         }
     }
-    sensor->buflen += snprintf(sensor->buf + sensor->buflen, BUFSIZ-sensor->buflen, "%s%s",
-                               value, sensor->nvalues-1 != idx ? ", " : "");
+    int avail = BUFSIZ - sensor->buflen;
+    if(avail <= 0){
+        LOGWARN("Sensor %d: writing buffer overfull", sensor->idx);
+        WARNX("Overfull; clear all");
+        sensor->lastvalidx = -1;
+        sensor->buflen = 0;
+        return false;
+    }
+    int n = snprintf(sensor->buf + sensor->buflen, avail, "%s%s",
+                              value, sensor->nvalues-1 != idx ? ", " : "");
+    if(n >= avail){
+        // Data would be truncated  handle error or discard
+        n = avail - 1;
+        LOGWARN("Sensor %d: writing buffer truncated", sensor->idx);
+    }
+    sensor->buflen += n;
     sensor->lastvalidx = idx;
     DBG("Now buf[%d]=%s", sensor->idx, sensor->buf);
     return true;