Kernel: Use symbolic constants for file modes

This fixes a bug where the mode of a FIFO was reported as 001000 instead
of 0010000 (you see the difference? me nethier), and hopefully doesn't
introduce new bugs. I've left 0777 and similar in a few places, because
that is *more* readable than its symbolic version.

5 files changed, 52 insertions, 30 deletions

diff --git a/Kernel/FileSystem/FileDescription.cpp b/Kernel/FileSystem/FileDescription.cpp
index 4b76e4ca4a..c4c3f8f700 100644
--- a/Kernel/FileSystem/FileDescription.cpp
+++ b/Kernel/FileSystem/FileDescription.cpp
@@ -78,12 +78,12 @@ KResult FileDescription::fstat(stat& buffer)
 {
     if (is_fifo()) {
         memset(&buffer, 0, sizeof(buffer));
-        buffer.st_mode = 001000;
+        buffer.st_mode = S_IFIFO;
         return KSuccess;
     }
     if (is_socket()) {
         memset(&buffer, 0, sizeof(buffer));
-        buffer.st_mode = 0140000;
+        buffer.st_mode = S_IFSOCK;
         return KSuccess;
     }
 
diff --git a/Kernel/FileSystem/InodeMetadata.h b/Kernel/FileSystem/InodeMetadata.h
index eb4f672ed8..843a2b691f 100644
--- a/Kernel/FileSystem/InodeMetadata.h
+++ b/Kernel/FileSystem/InodeMetadata.h
@@ -40,16 +40,16 @@ inline constexpr u32 encoded_device(unsigned major, unsigned minor)
     return (minor & 0xff) | (major << 8) | ((minor & ~0xff) << 12);
 }
 
-inline bool is_directory(mode_t mode) { return (mode & 0170000) == 0040000; }
-inline bool is_character_device(mode_t mode) { return (mode & 0170000) == 0020000; }
-inline bool is_block_device(mode_t mode) { return (mode & 0170000) == 0060000; }
-inline bool is_regular_file(mode_t mode) { return (mode & 0170000) == 0100000; }
-inline bool is_fifo(mode_t mode) { return (mode & 0170000) == 0010000; }
-inline bool is_symlink(mode_t mode) { return (mode & 0170000) == 0120000; }
-inline bool is_socket(mode_t mode) { return (mode & 0170000) == 0140000; }
-inline bool is_sticky(mode_t mode) { return mode & 01000; }
-inline bool is_setuid(mode_t mode) { return mode & 04000; }
-inline bool is_setgid(mode_t mode) { return mode & 02000; }
+inline bool is_directory(mode_t mode) { return (mode & S_IFMT) == S_IFDIR; }
+inline bool is_character_device(mode_t mode) { return (mode & S_IFMT) == S_IFCHR; }
+inline bool is_block_device(mode_t mode) { return (mode & S_IFMT) == S_IFBLK; }
+inline bool is_regular_file(mode_t mode) { return (mode & S_IFMT) == S_IFREG; }
+inline bool is_fifo(mode_t mode) { return (mode & S_IFMT) == S_IFIFO; }
+inline bool is_symlink(mode_t mode) { return (mode & S_IFMT) == S_IFLNK; }
+inline bool is_socket(mode_t mode) { return (mode & S_IFMT) == S_IFSOCK; }
+inline bool is_sticky(mode_t mode) { return mode & S_ISVTX; }
+inline bool is_setuid(mode_t mode) { return mode & S_ISUID; }
+inline bool is_setgid(mode_t mode) { return mode & S_ISGID; }
 
 struct InodeMetadata {
     bool is_valid() const { return inode.is_valid(); }
@@ -63,10 +63,10 @@ struct InodeMetadata {
         if (u == 0)
             return true;
         if (uid == u)
-            return mode & 0400;
+            return mode & S_IRUSR;
         if (gid == g || eg.contains(gid))
-            return mode & 0040;
-        return mode & 0004;
+            return mode & S_IRGRP;
+        return mode & S_IROTH;
     }
 
     bool may_write(uid_t u, gid_t g, const FixedArray<gid_t>& eg) const
@@ -74,10 +74,10 @@ struct InodeMetadata {
         if (u == 0)
             return true;
         if (uid == u)
-            return mode & 0200;
+            return mode & S_IWUSR;
         if (gid == g || eg.contains(gid))
-            return mode & 0020;
-        return mode & 0002;
+            return mode & S_IWGRP;
+        return mode & S_IWOTH;
     }
 
     bool may_execute(uid_t u, gid_t g, const FixedArray<gid_t>& eg) const
@@ -85,10 +85,10 @@ struct InodeMetadata {
         if (u == 0)
             return true;
         if (uid == u)
-            return mode & 0100;
+            return mode & S_IXUSR;
         if (gid == g || eg.contains(gid))
-            return mode & 0010;
-        return mode & 0001;
+            return mode & S_IXGRP;
+        return mode & S_IXOTH;
     }
 
     bool is_directory() const { return Kernel::is_directory(mode); }
diff --git a/Kernel/FileSystem/ProcFS.cpp b/Kernel/FileSystem/ProcFS.cpp
index 8c5b3b9a01..567774ccd6 100644
--- a/Kernel/FileSystem/ProcFS.cpp
+++ b/Kernel/FileSystem/ProcFS.cpp
@@ -1144,30 +1144,30 @@ InodeMetadata ProcFSInode::metadata() const
     }
 
     if (proc_parent_directory == PDI_PID_fd) {
-        metadata.mode = 00120700;
+        metadata.mode = S_IFLNK | S_IRUSR | S_IWUSR | S_IXUSR;
         return metadata;
     }
 
     switch (proc_file_type) {
     case FI_Root_self:
-        metadata.mode = 0120444;
+        metadata.mode = S_IFLNK | S_IRUSR | S_IRGRP | S_IROTH;
         break;
     case FI_PID_cwd:
     case FI_PID_exe:
     case FI_PID_root:
-        metadata.mode = 0120400;
+        metadata.mode = S_IFLNK | S_IRUSR;
         break;
     case FI_Root:
     case FI_Root_sys:
     case FI_Root_net:
-        metadata.mode = 040555;
+        metadata.mode = S_IFDIR | S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;
         break;
     case FI_PID:
     case FI_PID_fd:
-        metadata.mode = 040500;
+        metadata.mode = S_IFDIR | S_IRUSR | S_IXUSR;
         break;
     default:
-        metadata.mode = 0100444;
+        metadata.mode = S_IFREG | S_IRUSR | S_IRGRP | S_IROTH;
         break;
     }
 
diff --git a/Kernel/FileSystem/TmpFS.cpp b/Kernel/FileSystem/TmpFS.cpp
index a0cd624137..86d141010a 100644
--- a/Kernel/FileSystem/TmpFS.cpp
+++ b/Kernel/FileSystem/TmpFS.cpp
@@ -125,8 +125,8 @@ KResultOr<NonnullRefPtr<Inode>> TmpFS::create_inode(InodeIdentifier parent_id, c
 KResult TmpFS::create_directory(InodeIdentifier parent_id, const String& name, mode_t mode, uid_t uid, gid_t gid)
 {
     // Ensure it's a directory.
-    mode &= ~0170000;
-    mode |= 0040000;
+    mode &= ~S_IFMT;
+    mode |= S_IFDIR;
     auto result = create_inode(parent_id, name, mode, 0, 0, uid, gid);
     if (result.is_error())
         return result.error();
@@ -155,7 +155,7 @@ NonnullRefPtr<TmpFSInode> TmpFSInode::create(TmpFS& fs, InodeMetadata metadata,
 NonnullRefPtr<TmpFSInode> TmpFSInode::create_root(TmpFS& fs)
 {
     InodeMetadata metadata;
-    metadata.mode = 0041777;
+    metadata.mode = S_IFDIR | S_ISVTX | 0777;
     return create(fs, metadata, { fs.fsid(), 1 });
 }
 
diff --git a/Kernel/UnixTypes.h b/Kernel/UnixTypes.h
index f74c28e402..7830cab91c 100644
--- a/Kernel/UnixTypes.h
+++ b/Kernel/UnixTypes.h
@@ -108,6 +108,28 @@
 #define FUTEX_WAIT 1
 #define FUTEX_WAKE 2
 
+#define S_IFMT 0170000
+#define S_IFDIR 0040000
+#define S_IFCHR 0020000
+#define S_IFBLK 0060000
+#define S_IFREG 0100000
+#define S_IFIFO 0010000
+#define S_IFLNK 0120000
+#define S_IFSOCK 0140000
+
+#define S_ISUID 04000
+#define S_ISGID 02000
+#define S_ISVTX 01000
+#define S_IRUSR 0400
+#define S_IWUSR 0200
+#define S_IXUSR 0100
+#define S_IRGRP 0040
+#define S_IWGRP 0020
+#define S_IXGRP 0010
+#define S_IROTH 0004
+#define S_IWOTH 0002
+#define S_IXOTH 0001
+
 /* c_cc characters */
 #define VINTR 0
 #define VQUIT 1