Btrfs: add new module

src/detection/btrfs/btrfs_linux.c

@@ -0,0 +1,166 @@
+#include "btrfs.h"
+
+#include "common/io/io.h"
+
+enum { uuidLen = (uint32_t) __builtin_strlen("00000000-0000-0000-0000-000000000000") };
+
+static const char* enumerateDevices(FFBtrfsResult* item, FFstrbuf* path, FFstrbuf* buffer)
+{
+    ffStrbufAppendS(path, "devices/");
+    FF_AUTO_CLOSE_DIR DIR* dirp = opendir(path->chars);
+    if(dirp == NULL)
+        return "opendir(\"/sys/fs/btrfs/UUID/devices\") == NULL";
+    const uint32_t devicesPathLen = path->length;
+
+    struct dirent* entry;
+    while ((entry = readdir(dirp)) != NULL)
+    {
+        if (entry->d_name[0] == '.')
+            continue;
+
+        if (item->devices.length)
+            ffStrbufAppendC(&item->devices, ',');
+        ffStrbufAppendS(&item->devices, entry->d_name);
+        ffStrbufAppendS(path, entry->d_name);
+        ffStrbufAppendS(path, "/size");
+
+        if (ffReadFileBuffer(path->chars, buffer))
+            item->totalSize += ffStrbufToUInt(buffer, 0) * 512;
+
+        ffStrbufSubstrBefore(path, devicesPathLen);
+    }
+
+    return NULL;
+}
+
+static const char* enumerateFeatures(FFBtrfsResult* item, FFstrbuf* path)
+{
+    ffStrbufAppendS(path, "features/");
+    FF_AUTO_CLOSE_DIR DIR* dirp = opendir(path->chars);
+    if(dirp == NULL)
+        return "opendir(\"/sys/fs/btrfs/UUID/features\") == NULL";
+    const uint32_t featuresPathLen = path->length;
+
+    struct dirent* entry;
+    while ((entry = readdir(dirp)) != NULL)
+    {
+        if (entry->d_name[0] == '.')
+            continue;
+        if (item->features.length)
+            ffStrbufAppendC(&item->features, ',');
+        ffStrbufAppendS(&item->features, entry->d_name);
+
+        ffStrbufSubstrBefore(path, featuresPathLen);
+    }
+
+    return NULL;
+}
+
+static const char* detectAllocation(FFBtrfsResult* item, FFstrbuf* path, FFstrbuf* buffer)
+{
+    ffStrbufAppendS(path, "allocation/");
+    const uint32_t AllocationPathLen = path->length;
+
+    ffStrbufAppendS(path, "global_rsv_size");
+    if (ffReadFileBuffer(path->chars, buffer))
+        item->globalReservationTotal = ffStrbufToUInt(buffer, 0);
+    else
+        return "ffReadFileBuffer(\"/sys/fs/btrfs/UUID/allocation/global_rsv_size\") == NULL";
+    ffStrbufSubstrBefore(path, AllocationPathLen);
+
+    ffStrbufAppendS(path, "global_rsv_reserved");
+    if (ffReadFileBuffer(path->chars, buffer))
+        item->globalReservationUsed = ffStrbufToUInt(buffer, 0);
+    ffStrbufSubstrBefore(path, AllocationPathLen);
+    item->globalReservationUsed = item->globalReservationTotal - item->globalReservationUsed;
+
+    #define FF_BTRFS_DETECT_TYPE(index, _type) \
+    ffStrbufAppendS(path, #_type "/total_bytes"); \
+    if (ffReadFileBuffer(path->chars, buffer)) \
+        item->allocation[index].total = ffStrbufToUInt(buffer, 0); \
+    ffStrbufSubstrBefore(path, AllocationPathLen); \
+    \
+    ffStrbufAppendS(path, #_type "/bytes_used"); \
+    if (ffReadFileBuffer(path->chars, buffer)) \
+        item->allocation[index].used = ffStrbufToUInt(buffer, 0); \
+    ffStrbufSubstrBefore(path, AllocationPathLen); \
+    \
+    ffStrbufAppendS(path, #_type "/dup"); \
+    item->allocation[index].dup = ffPathExists(path->chars, FF_PATHTYPE_DIRECTORY); \
+    ffStrbufSubstrBefore(path, AllocationPathLen); \
+    \
+    item->allocation[index].type = #_type;
+
+    FF_BTRFS_DETECT_TYPE(0, data);
+    FF_BTRFS_DETECT_TYPE(1, metadata);
+    FF_BTRFS_DETECT_TYPE(2, system);
+
+    #undef FF_BTRFS_DETECT_TYPE
+
+    return NULL;
+}
+
+const char* ffDetectBtrfs(FFlist* result)
+{
+    FF_STRBUF_AUTO_DESTROY path = ffStrbufCreateS("/sys/fs/btrfs/");
+    const uint32_t basePathLen = path.length;
+
+    FF_AUTO_CLOSE_DIR DIR* dirp = opendir(path.chars);
+    if(dirp == NULL)
+        return "opendir(\"/sys/fs/btrfs\") == NULL";
+
+    FF_STRBUF_AUTO_DESTROY buffer = ffStrbufCreate();
+
+    struct dirent* entry;
+    while ((entry = readdir(dirp)) != NULL)
+    {
+        if (entry->d_name[0] == '.')
+            continue;
+        if (strlen(entry->d_name) != uuidLen)
+            continue;
+
+        FFBtrfsResult* item = ffListAdd(result);
+        (*item) = (FFBtrfsResult){};
+        ffStrbufInitNS(&item->uuid, uuidLen, entry->d_name);
+        ffStrbufInit(&item->name);
+        ffStrbufInit(&item->devices);
+        ffStrbufInit(&item->features);
+
+        ffStrbufAppendNS(&path, uuidLen, entry->d_name);
+        ffStrbufAppendC(&path, '/');
+        const uint32_t itemPathLen = path.length;
+
+        ffStrbufAppendS(&path, "label");
+        if (ffAppendFileBuffer(path.chars, &item->name))
+            ffStrbufTrimRightSpace(&item->name);
+        ffStrbufSubstrBefore(&path, itemPathLen);
+
+        enumerateDevices(item, &path, &buffer);
+        ffStrbufSubstrBefore(&path, itemPathLen);
+
+        enumerateFeatures(item, &path);
+        ffStrbufSubstrBefore(&path, itemPathLen);
+
+        ffStrbufAppendS(&path, "generation");
+        if (ffReadFileBuffer(path.chars, &buffer))
+            item->generation = (uint32_t) ffStrbufToUInt(&buffer, 0);
+        ffStrbufSubstrBefore(&path, itemPathLen);
+
+        ffStrbufAppendS(&path, "nodesize");
+        if (ffReadFileBuffer(path.chars, &buffer))
+            item->nodeSize = (uint32_t) ffStrbufToUInt(&buffer, 0);
+        ffStrbufSubstrBefore(&path, itemPathLen);
+
+        ffStrbufAppendS(&path, "sectorsize");
+        if (ffReadFileBuffer(path.chars, &buffer))
+            item->sectorSize = (uint32_t) ffStrbufToUInt(&buffer, 0);
+        ffStrbufSubstrBefore(&path, itemPathLen);
+
+        detectAllocation(item, &path, &buffer);
+
+        // finally
+        ffStrbufSubstrBefore(&path, basePathLen);
+    }
+
+    return NULL;
+}