feat: add sfsModeOf and sfsChmod to sfs

src/sfs.c

@@ -1266,3 +1266,161 @@ uint64 sfsCtimeOf(int32 inodeNum)
     return inode.ctime;
 }
 
+uint32 sfsModeOf(int32 inodeNum)
+{
+    if (!isMounted || inodeNum <= 0)
+        return 0;
+    SfsInode inode;
+    if (!readInode(inodeNum, &inode))
+        return 0;
+    return inode.mode;
+}
+
+bool sfsChmod(int32 inodeNum, uint32 mode)
+{
+    if (!isMounted || inodeNum <= 0)
+        return false;
+    SfsInode inode;
+    if (!readInode(inodeNum, &inode))
+        return false;
+    inode.mode = mode;
+    inode.ctime = (uint32)rtcNow();
+    return writeInodeRaw(inodeNum, &inode);
+}
+
+uint32 sfsUidOf(int32 inodeNum)
+{
+    if (!isMounted || inodeNum <= 0)
+        return 0;
+    SfsInode inode;
+    if (!readInode(inodeNum, &inode))
+        return 0;
+    return inode.uid;
+}
+
+bool sfsChown(int32 inodeNum, uint32 newUid)
+{
+    if (!isMounted || inodeNum <= 0)
+        return false;
+    SfsInode inode;
+    if (!readInode(inodeNum, &inode))
+        return false;
+    inode.uid = newUid;
+    inode.ctime = (uint32)rtcNow();
+    return writeInodeRaw(inodeNum, &inode);
+}
+
+uint32 sfsGidOf(int32 inodeNum)
+{
+    if (!isMounted || inodeNum <= 0)
+        return 0;
+    SfsInode inode;
+    if (!readInode(inodeNum, &inode))
+        return 0;
+    return inode.gid;
+}
+
+bool sfsChgrp(int32 inodeNum, uint32 newGid)
+{
+    if (!isMounted || inodeNum <= 0)
+        return false;
+    SfsInode inode;
+    if (!readInode(inodeNum, &inode))
+        return false;
+    inode.gid = newGid;
+    inode.ctime = (uint32)rtcNow();
+    return writeInodeRaw(inodeNum, &inode);
+}
+
+bool sfsTruncate(int32 inodeNum, uint64 newSize)
+{
+    if (!isMounted || inodeNum <= 0 || newSize > 0xFFFFFFFFu)
+        return false;
+    SfsInode inode;
+    if (!readInode(inodeNum, &inode))
+        return false;
+    if (inode.type != sfsTypeFile)
+        return false;
+    return sfsTruncateInode(&inode, inodeNum, (uint32)newSize);
+}
+
+int64 sfsReadAt(int32 inodeNum, uint64 offset, void* buffer, uint64 length)
+{
+    if (!isMounted || inodeNum <= 0)
+        return -1;
+    SfsInode inode;
+    if (!readInode(inodeNum, &inode))
+        return -1;
+    if (inode.type != sfsTypeFile && inode.type != sfsTypeDir && inode.type != sfsTypeSymlink)
+        return -1;
+    if (offset >= inode.size)
+        return 0;
+
+    uint64 want = length;
+    if (want > (uint64)inode.size - offset)
+        want = (uint64)inode.size - offset;
+
+    uint8* dst = (uint8*)buffer;
+    uint64 done = 0;
+    while (done < want) {
+        uint64 pos = offset + done;
+        uint32 logicalBlock = (uint32)(pos / sfsBlockSize);
+        uint32 within = (uint32)(pos % sfsBlockSize);
+        uint32 chunk = sfsBlockSize - within;
+        if ((uint64)chunk > want - done)
+            chunk = (uint32)(want - done);
+
+        uint32 blockAbs;
+        if (getBlockForRead(&inode, logicalBlock, &blockAbs)) {
+            uint8 blockBuf[sfsBlockSize];
+            if (!blockRead(blockAbs, blockBuf))
+                break;
+            memcpy(dst + done, blockBuf + within, chunk);
+        } else {
+            memset(dst + done, 0, chunk);
+        }
+        done += chunk;
+    }
+    return (int64)done;
+}
+
+int64 sfsWriteAt(int32 inodeNum, uint64 offset, const void* buffer, uint64 length)
+{
+    if (!isMounted || inodeNum <= 0)
+        return -1;
+    SfsInode inode;
+    if (!readInode(inodeNum, &inode))
+        return -1;
+    if (inode.type != sfsTypeFile && inode.type != sfsTypeDir && inode.type != sfsTypeSymlink)
+        return -1;
+    if (length == 0)
+        return 0;
+
+    if (offset > inode.size) {
+        if (!sfsWriteRaw(&inode, inodeNum, inode.size, nullptr, offset - inode.size))
+            return -1;
+    }
+    if (!sfsWriteRaw(&inode, inodeNum, offset, buffer, length))
+        return -1;
+    return (int64)length;
+}
+
+bool sfsReaddirAt(int32 dirInode, uint32 index, char* nameOut, uint32 nameCap, uint32* typeOut)
+{
+    if (!isMounted || sfsTypeOf(dirInode) != sfsTypeDir)
+        return false;
+
+    SfsDirEntry entry;
+    uint64 pos = (uint64)index * sizeof(SfsDirEntry);
+    if (sfsReadAt(dirInode, pos, &entry, sizeof(entry)) != (int64)sizeof(entry))
+        return false;
+
+    uint64 nlen = strlen(entry.name);
+    if (nlen >= nameCap)
+        nlen = nameCap - 1;
+    memcpy(nameOut, entry.name, nlen);
+    nameOut[nlen] = 0;
+    if (typeOut)
+        *typeOut = entry.type;
+    return true;
+}