kernel+libc+libos: Add inode type for sockets

kernel/src/fs/VFS.h

@@ -17,6 +17,7 @@ namespace VFS
         BlockDevice,
         Symlink,
         FIFO,
+        Socket,
     };
 
     class Inode;

kernel/src/sys/open.cpp

@@ -55,6 +55,8 @@ Result<u64> sys_openat(Registers*, SyscallArgs args)
     // This should only be possible if O_NOFOLLOW was in flags.
     if (inode->type() == VFS::InodeType::Symlink) return err(ELOOP);
 
+    if (inode->type() == VFS::InodeType::Socket) return err(ENXIO);
+
     if (flags & O_TMPFILE)
     {
         if (inode->type() != VFS::InodeType::Directory) return err(EINVAL);

kernel/src/sys/stat.cpp

@@ -18,6 +18,7 @@ static mode_t make_mode(mode_t mode, VFS::InodeType type)
     case VFS::InodeType::BlockDevice: result |= S_IFBLK; break;
     case VFS::InodeType::Symlink: result |= S_IFLNK; break;
     case VFS::InodeType::FIFO: result |= S_IFIFO; break;
+    case VFS::InodeType::Socket: result |= S_IFSOCK; break;
     default: break;
     }
 

libc/include/bits/modes.h

@@ -10,6 +10,7 @@
 #define S_IFBLK 030000
 #define S_IFDIR 040000
 #define S_IFCHR 050000
+#define S_IFSOCK 060000
 
 #define __CHECK_TYPE(mode, type) (((mode)&S_IFMT) == type)
 
@@ -19,6 +20,7 @@
 #define S_ISBLK(mode) __CHECK_TYPE(mode, S_IFBLK)
 #define S_ISLNK(mode) __CHECK_TYPE(mode, S_IFLNK)
 #define S_ISFIFO(mode) __CHECK_TYPE(mode, S_IFIFO)
+#define S_ISSOCK(mode) __CHECK_TYPE(mode, S_IFSOCK)
 
 #define S_IRWXU 0700
 #define S_IRUSR 0400

libos/src/Mode.cpp

@@ -21,6 +21,7 @@ namespace os
         if (S_ISBLK(mode)) return 'b';
         if (S_ISLNK(mode)) return 'l';
         if (S_ISFIFO(mode)) return 'p';
+        if (S_ISSOCK(mode)) return 's';
 
         return '?';
     }