Initial prototype.

1 files changed, 200 insertions, 0 deletions

diff --git a/hwmon.c b/hwmon.c
new file mode 100644
index 0000000..70c3129
--- /dev/null
+++ b/hwmon.c
@@ -0,0 +1,200 @@
+#define _POSIX_C_SOURCE 200809L
+
+#include <dirent.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "hwmon.h"
+
+// size of input buffer for paths and lines
+#define BUF_SIZE 256
+// size of input buffer for labels
+#define LABEL_SIZE 32
+
+static void hwmon_collect(scrape_req *req, void *ctx);
+
+const struct collector hwmon_collector = {
+  .name = "hwmon",
+  .collect = hwmon_collect,
+};
+
+static double hwmon_conv_millis(const char *text) {
+  char *endptr;
+  double value = strtod(text, &endptr);
+  if (*endptr == '\n' || *endptr == '\0')
+    return value / 1000;
+  return NAN;
+}
+
+static double hwmon_conv_id(const char *text) {
+  char *endptr;
+  double value = strtod(text, &endptr);
+  if (*endptr == '\n' || *endptr == '\0')
+    return value;
+  return NAN;
+}
+
+static double hwmon_conv_flag(const char *text) {
+  if ((text[0] == '0' || text[0] == '1') && (text[1] == '\n' || text[1] == '\0'))
+    return text[0] - '0';
+  return NAN;
+}
+
+struct metric_type {
+  const char *suffix;
+  const char *metric;
+  double (*conv)(const char *text);
+};
+
+struct metric_data {
+  const char *prefix;
+  const struct metric_type *types;
+};
+
+static const struct metric_data metrics[] = {
+  {
+    .prefix = "in",
+    .types = (const struct metric_type[]){
+      {
+        .suffix = "_input",
+        .metric = "node_hwmon_in_volts",
+        .conv = hwmon_conv_millis,
+      },
+      {
+        .suffix = "_min",
+        .metric = "node_hwmon_in_min_volts",
+        .conv = hwmon_conv_millis,
+      },
+      {
+        .suffix = "_max",
+        .metric = "node_hwmon_in_max_volts",
+        .conv = hwmon_conv_millis,
+      },
+      {
+        .suffix = "_alarm",
+        .metric = "node_hwmon_in_alarm",
+        .conv = hwmon_conv_flag,
+      },
+      { .suffix = 0 },
+    },
+  },
+  {
+    .prefix = "fan",
+    .types = (const struct metric_type[]){
+      {
+        .suffix = "_input",
+        .metric = "node_hwmon_fan_rpm",
+        .conv = hwmon_conv_id,
+      },
+      {
+        .suffix = "_min",
+        .metric = "node_hwmon_fan_min_rpm",
+        .conv = hwmon_conv_id,
+      },
+      {
+        .suffix = "_alarm",
+        .metric = "node_hwmon_fan_alarm",
+        .conv = hwmon_conv_flag,
+      },
+      { .suffix = 0 },
+    },
+  },
+  {
+    .prefix = "temp",
+    .types = (const struct metric_type[]){
+      {
+        .suffix = "_input",
+        .metric = "node_hwmon_temp_celsius",
+        .conv = hwmon_conv_millis,
+      },
+      { .suffix = 0 },
+    },
+  },
+  { .prefix = 0 },
+};
+
+static void hwmon_collect(scrape_req *req, void *ctx) {
+  // buffers
+
+  char chip_label[LABEL_SIZE];
+  char sensor_label[LABEL_SIZE];
+
+  const char *labels[][2] = {
+    { "chip", chip_label },
+    { "sensor", sensor_label },
+    { 0, 0 },
+  };
+
+  char path[BUF_SIZE];
+  char buf[BUF_SIZE];
+  size_t len;
+
+  FILE *f;
+
+  DIR *root;
+  struct dirent *dent;
+
+  // iterate over all hwmon instances in /sys/class/hwmon
+
+  root = opendir("/sys/class/hwmon");
+  if (!root)
+    return;
+
+  while ((dent = readdir(root))) {
+    if (strncmp(dent->d_name, "hwmon", 5) != 0)
+      continue;
+    snprintf(path, sizeof path, "/sys/class/hwmon/%s", dent->d_name);
+
+    len = readlink(path, buf, sizeof buf);
+    if (len > 14 && memcmp(buf, "../../devices/", 14) == 0) {
+      char *start = buf + 14;
+      char *end = strchr(start, '/');
+      if (end)
+        end = strchr(end + 1, '/');
+      if (end)
+        *end = '\0';
+      snprintf(chip_label, sizeof chip_label, "%s", start);
+    } else {
+      snprintf(chip_label, sizeof chip_label, "unknown");
+    }
+
+    DIR *dir = opendir(path);
+    if (!dir)
+      continue;
+
+    while ((dent = readdir(dir))) {
+      for (const struct metric_data *metric = metrics; metric->prefix; metric++) {
+        if (strncmp(dent->d_name, metric->prefix, strlen(metric->prefix)) != 0)
+          continue;
+        char *suffix = strchr(dent->d_name, '_');
+        if (!suffix)
+          continue;
+
+        snprintf(sensor_label, sizeof sensor_label, "%.*s", (int)(suffix - dent->d_name), dent->d_name);
+
+        for (const struct metric_type *type = metric->types; type->suffix; type++) {
+          if (strcmp(suffix, type->suffix) != 0)
+            continue;
+
+          snprintf(buf, sizeof buf, "%s/%s", path, dent->d_name);
+          f = fopen(buf, "r");
+          if (!f)
+            continue;
+          if (fgets(buf, sizeof buf, f)) {
+            double value = type->conv(buf);
+            if (!isnan(value))
+              scrape_write(req, type->metric, labels, value);
+          }
+          fclose(f);
+        }
+      }
+    }
+
+    closedir(dir);
+  }
+
+  closedir(root);
+}