1 files changed, 142 insertions, 0 deletions
diff --git a/mdstat.c b/mdstat.c
new file mode 100644
index 0000000..bc8b62a
--- /dev/null
+++ b/mdstat.c
@@ -0,0 +1,142 @@
+#define _GNU_SOURCE
+#include <fcntl.h>
+#include <glob.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "scrape.h"
+#include "util.h"
+
+// size of input buffer for paths and lines
+#define BUF_SIZE 256
+
+static void mdstat_collect(scrape_req *req, void *ctx);
+
+const struct collector mdstat_collector = {
+  .name = "mdstat",
+  .collect = mdstat_collect,
+};
+
+static ssize_t
+read_file_at(int dirfd, char *pathname, char *buf, size_t bufsiz) {
+  int fd = openat(dirfd, pathname, O_RDONLY);
+  if (fd < 0)
+    return -1;
+
+  ssize_t r = read(fd, buf, bufsiz - 1);
+  close(fd);
+  if (r < 0)
+    return -1;
+
+  if (buf[r-1] == '\n')
+    r--;
+
+  buf[r] = 0;
+  return r;
+}
+
+void
+scrape_write_md_label(scrape_req *req, char *name, char *md, char *label, char *value, double d) {
+  struct label labels[] = {
+    { .key = "device", .value = md },
+    { .key = label, .value = value },
+    LABEL_END,
+  };
+  scrape_write(req, name, labels, d);
+}
+
+static void mdstat_collect_dir(scrape_req *req, char *dir) {
+  char buf[BUF_SIZE];
+  char md[32] = { 0 };
+  memcpy(md, dir + 11 /* "/sys/block/" */, strlen(dir) - 11 - 3 /* "/md" */);
+
+  int dirfd = open(dir, O_PATH);
+  if (dirfd < 0)
+    return;
+
+  struct label md_label[] = {
+    { .key = "device", .value = md },
+    LABEL_END,
+  };
+
+  if (read_file_at(dirfd, "level", buf, sizeof buf) > 0)
+    scrape_write_md_label(req, "node_md_level", md, "level", buf, 1);
+
+  if (read_file_at(dirfd, "raid_disks", buf, sizeof buf) > 0)
+    scrape_write(req, "node_md_disks", md_label, atof(buf));
+
+  if (read_file_at(dirfd, "metadata_version", buf, sizeof buf) > 0)
+    scrape_write_md_label(req, "node_md_metadata_version", md, "version", buf, 1);
+
+  if (read_file_at(dirfd, "array_state", buf, sizeof buf) > 0)
+    scrape_write_md_label(req, "node_md_state", md, "state", buf, 1);
+
+  // uuid
+
+  if (read_file_at(dirfd, "chunk_size", buf, sizeof buf) > 0)
+    scrape_write(req, "node_md_chunk_size", md_label, atof(buf));
+
+  if (read_file_at(dirfd, "degraded", buf, sizeof buf) > 0)
+    scrape_write(req, "node_md_degraded_disks", md_label, atof(buf));
+
+  if (read_file_at(dirfd, "sync_action", buf, sizeof buf) > 0)
+    scrape_write_md_label(req, "node_md_sync_action", md, "action", buf, 1);
+
+  if (read_file_at(dirfd, "sync_completed", buf, sizeof buf) > 0) {
+    if (strcmp(buf, "none") != 0) {
+      double a, b;
+      if (sscanf(buf, "%lf / %lf", &a, &b) == 2)
+        scrape_write(req, "node_md_sync_completed", md_label, a / b);
+      if (read_file_at(dirfd, "sync_speed", buf, sizeof buf) > 0)
+        scrape_write(req, "node_md_sync_speed", md_label, atof(buf));
+    }
+  }
+
+  close(dirfd);
+
+  char stateglob[BUF_SIZE];
+  strcpy(stateglob, dir);
+  strcat(stateglob, "/dev-*/state");
+
+  glob_t globbuf = { 0 };
+  if (glob(stateglob, GLOB_NOSORT, 0, &globbuf) != 0)
+    return;
+
+  for (size_t i = 0; i < globbuf.gl_pathc; i++) {
+    char dev[16] = { 0 };
+    memcpy(dev, globbuf.gl_pathv[i] + strlen(dir) + 5 /* "/dev-" */,
+        strlen(globbuf.gl_pathv[i]) - strlen(dir) - 5 - 6 /* "/state" */);
+
+    if (read_file_at(AT_FDCWD, globbuf.gl_pathv[i], buf, sizeof buf)) {
+      struct label labels[] = {
+        { .key = "device", .value = md },
+        { .key = "disk", .value = dev },
+        { .key = "state", .value = buf },
+        LABEL_END,
+      };
+      scrape_write(req, "node_md_disk_state", labels, 1);
+    }
+  }
+
+  globfree(&globbuf);
+}
+
+static void mdstat_collect(scrape_req *req, void *ctx) {
+  (void) ctx;
+
+  // scan /sys/block/md*/md/ for metrics
+
+  if (access("/proc/mdstat", F_OK) != 0)
+    return;
+
+  glob_t globbuf = { 0 };
+  if (glob("/sys/block/md*/md", GLOB_NOSORT | GLOB_ONLYDIR, 0, &globbuf) != 0)
+    return;
+
+  for (size_t i = 0; i < globbuf.gl_pathc; i++)
+    mdstat_collect_dir(req, globbuf.gl_pathv[i]);
+
+  globfree(&globbuf);
+}