weather: add a fuzzing executable

Since this parses raw data from the internet in C, it should really be
fuzzed.

modules/fuzz-weather.c

@@ -0,0 +1,106 @@
+#include "weather.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+int main(int argc, char* argv[])
+{
+    if (argc != 2) {
+        return EXIT_FAILURE;
+    }
+
+    struct weather_curl_buffer buf;
+#define BUF_INIT_SIZE ((size_t)16384)
+    buf.buffer = (char*)malloc(BUF_INIT_SIZE * sizeof(char));
+    if (!buf.buffer) {
+        printf("failed to reallocate %zu bytes\n", BUF_INIT_SIZE);
+        free(buf.buffer);
+        return EXIT_FAILURE;
+    }
+    buf.size = 0;
+    buf.capacity = BUF_INIT_SIZE;
+
+    int fin = open(argv[1], O_CLOEXEC);
+    if (fin < 0) {
+        printf("failed to open input %s: %s\n", argv[1], strerror(errno));
+        free(buf.buffer);
+        return EXIT_FAILURE;
+    }
+
+    size_t bytes_read;
+    do {
+        bytes_read = read(fin, buf.buffer + buf.size, buf.capacity - buf.size);
+        if (bytes_read < 0) {
+            printf("failed to read input: %s\n", strerror(errno));
+            close(fin);
+            return EXIT_FAILURE;
+        }
+
+        buf.size += bytes_read;
+        if (buf.size == buf.capacity) {
+            size_t newcap = 2 * buf.capacity;
+            char* newbuf = (char*)realloc(buf.buffer, newcap * sizeof(char));
+            if (!newbuf) {
+                printf("failed to reallocate %zu bytes\n", newcap);
+                free(buf.buffer);
+                close(fin);
+                return EXIT_FAILURE;
+            }
+
+            buf.buffer = newbuf;
+            buf.capacity = newcap;
+        }
+    } while (bytes_read);
+    buf.buffer[buf.size] = '\0';
+
+    close(fin);
+
+    struct weather_info info;
+    memset(&info, 0, sizeof(info));
+    int ret = parse_weather_info(&buf, &info);
+
+    free(buf.buffer);
+
+    if (!ret) {
+#define print_field(s, f, t) \
+    printf(#f ": " t "\n", s.f)
+
+        print_field(info, station_town, "%s");
+        print_field(info, station_state, "%s");
+        print_field(info, year, "%d");
+        print_field(info, month, "%d");
+        print_field(info, day, "%d");
+        print_field(info, hour, "%d");
+        print_field(info, minute, "%d");
+        print_field(info, wind_direction, "%s");
+        print_field(info, wind_azimuth, "%d");
+        print_field(info, wind_mph, "%d");
+        print_field(info, wind_kmph, "%d");
+        print_field(info, wind_mps, "%d");
+        print_field(info, visibility, "%s");
+        print_field(info, sky_condition, "%s");
+        print_field(info, weather, "%s");
+        print_field(info, temp_c, "%f");
+        print_field(info, temp_f, "%f");
+        print_field(info, heat_index_c, "%f");
+        print_field(info, heat_index_f, "%f");
+        print_field(info, dew_point_c, "%f");
+        print_field(info, dew_point_f, "%f");
+        print_field(info, humidity, "%d");
+        print_field(info, pressure_mmhg, "%f");
+        print_field(info, pressure_hpa, "%d");
+    }
+
+    free(info.station_town);
+    free(info.station_state);
+    free(info.wind_direction);
+    free(info.visibility);
+    free(info.sky_condition);
+    free(info.weather);
+
+    return ret;
+}

modules/meson.build

@@ -153,6 +153,9 @@ if plugin_weather_enabled
   e = executable('test-weather', ['test-weather.c', 'weather-parse.c'],
                  dependencies: [pixman, fcft, tllist, curl])
   test('module-weather', e)
+
+  e = executable('fuzz-weather', ['fuzz-weather.c', 'weather-parse.c'],
+                 dependencies: [pixman, fcft, tllist, curl])
 endif
 
 if plugin_xkb_enabled