kernel+stat: Handle pipes correctly in stat()

apps/stat.cpp

@@ -11,6 +11,7 @@ static const char* file_type(mode_t mode)
     case S_IFDIR: return "directory";
     case S_IFCHR: return "character special device";
     case S_IFLNK: return "symbolic link";
+    case S_IFIFO: return "pipe";
     default: return "unknown file type";
     }
 }

kernel/src/fs/Pipe.h

@@ -30,6 +30,11 @@ class Pipe
 class PipeInodeBase : public VFS::FileInode
 {
   public:
+    VFS::InodeType type() const override
+    {
+        return VFS::InodeType::FIFO;
+    }
+
     Result<void> truncate(usize) override
     {
         return err(ENOTSUP);

kernel/src/fs/VFS.h

@@ -14,7 +14,8 @@ namespace VFS
         RegularFile,
         Directory,
         Device,
-        Symlink
+        Symlink,
+        FIFO,
     };
 
     class Inode;

kernel/src/sys/stat.cpp

@@ -15,6 +15,7 @@ static mode_t make_mode(mode_t mode, VFS::InodeType type)
     case VFS::InodeType::Directory: result |= S_IFDIR; break;
     case VFS::InodeType::Device: result |= S_IFCHR; break;
     case VFS::InodeType::Symlink: result |= S_IFLNK; break;
+    case VFS::InodeType::FIFO: result |= S_IFIFO; break;
     default: break;
     }
 

libc/include/bits/fixed-size-types.h

@@ -3,7 +3,7 @@
 #ifndef _BITS_FIXED_SIZE_TYPES_H
 #define _BITS_FIXED_SIZE_TYPES_H
 
-#if !defined(_SYS_TYPES_H) && !defined(_BITS_SETJMP_TYPES_H)
+#if !defined(_SYS_TYPES_H) && !defined(_BITS_SETJMP_TYPES_H) && !defined(_BITS_MAKEDEV_H)
 #error "Never include bits/fixed-size-types.h, use the standard <stdint.h> header instead."
 #endif
 

libc/include/bits/modes.h

@@ -6,6 +6,7 @@
 #define S_IFMT 070000
 #define S_IFREG 000000
 #define S_IFLNK 010000
+#define S_IFIFO 020000
 #define S_IFDIR 040000
 #define S_IFCHR 050000
 
@@ -15,6 +16,7 @@
 #define S_ISDIR(mode) __CHECK_TYPE(mode, S_IFDIR)
 #define S_ISCHR(mode) __CHECK_TYPE(mode, S_IFCHR)
 #define S_ISLNK(mode) __CHECK_TYPE(mode, S_IFLNK)
+#define S_ISFIFO(mode) __CHECK_TYPE(mode, S_IFIFO)
 
 #define S_IRWXU 0700
 #define S_IRUSR 0400