Merge pull request #4 from Richard-Qin-001/dev/shell

Rebuilt the system's underlying structure; it is now stable enough to merge. 

The system now supports a read-only file system and has a simple shell implemented.

1 files changed, 46 insertions, 0 deletions

diff --git a/include/kernel/elf.h b/include/kernel/elf.h
new file mode 100644
index 0000000..c216f1c
--- /dev/null
+++ b/include/kernel/elf.h
@@ -0,0 +1,46 @@
+#pragma once
+#include "common/types.h"
+
+#define ELF_MAGIC 0x464C457F // "\x7FELF" in little endian
+
+// ELF File Header
+struct elfhdr
+{
+    uint32 magic; // Must equal ELF_MAGIC
+    uint8 elf[12];
+    uint16 type;
+    uint16 machine;
+    uint32 version;
+    uint64 entry; // Program Entry Point (Virtual Address)
+    uint64 phoff; // File offset of the Program Header Table
+    uint64 shoff;
+    uint32 flags;
+    uint16 ehsize;
+    uint16 phentsize;
+    uint16 phnum; // Number of Program Headers
+    uint16 shentsize;
+    uint16 shnum;
+    uint16 shstrndx;
+};
+
+// Program Header
+// Describes how to load segments from a file into memory
+struct proghdr
+{
+    uint32 type;
+    uint32 flags;
+    uint64 off;   // Offset of the section in the file
+    uint64 vaddr; // Virtual address of the segment in memory
+    uint64 paddr;
+    uint64 filesz; // Size of the section in the file
+    uint64 memsz;  // The size of the segment in memory (memsz >= filesz)
+    uint64 align;
+};
+
+// Values for Proghdr type
+#define ELF_PROG_LOAD 1
+
+// Flag bits for Proghdr flags
+#define ELF_PROG_FLAG_EXEC 1
+#define ELF_PROG_FLAG_WRITE 2
+#define ELF_PROG_FLAG_READ 4
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