Started elf parser/loader

4 files changed, 87 insertions, 2 deletions

diff --git a/kernel/features/load.c b/kernel/features/load.c
index 14a3086..fd9883a 100644
--- a/kernel/features/load.c
+++ b/kernel/features/load.c
@@ -1,7 +1,10 @@
 // MIT License, Copyright (c) 2020 Marvin Borner
 
+#include <assert.h>
+#include <cpu.h>
 #include <def.h>
 #include <fs.h>
+#include <load.h>
 #include <mem.h>
 #include <proc.h>
 #include <str.h>
@@ -17,3 +20,34 @@ void bin_load(char *path, struct proc *proc)
 	proc->regs.eip = (u32)data;
 	strcpy(proc->name, path + 1);
 }
+
+int elf_verify(struct elf_header *h)
+{
+	return h->ident[0] == ELF_MAG && (strncmp((char *)&h->ident[1], "ELF", 3) == 0) &&
+	       h->ident[4] == ELF_32 && h->ident[5] == ELF_LITTLE && h->ident[6] == ELF_CURRENT &&
+	       h->machine == ELF_386 && (h->type == ET_REL || h->type == ET_EXEC);
+}
+
+void elf_load(char *path, struct proc *proc)
+{
+	char *data = read_file(path);
+	struct elf_header *h = (struct elf_header *)data;
+
+	assert(elf_verify(h));
+
+	printf("%d", h->type);
+	switch (h->type) {
+	case ET_EXEC:
+		return;
+	case ET_REL:
+		return;
+	}
+
+	loop();
+	u32 stack = (u32)malloc(0x1000) + 0x1000;
+	proc->regs.ebp = (u32)stack;
+	proc->regs.esp = (u32)stack;
+	proc->regs.useresp = (u32)stack;
+	proc->regs.eip = (u32)h->entry;
+	strcpy(proc->name, path + 1);
+}
diff --git a/kernel/features/proc.c b/kernel/features/proc.c
index 64a4ac1..7e6c95a 100644
--- a/kernel/features/proc.c
+++ b/kernel/features/proc.c
@@ -94,7 +94,7 @@ void proc_init()
 	irq_install_handler(0, scheduler);
 
 	root = proc_make();
-	bin_load("/init", root);
+	elf_load("/init", root);
 	proc_print();
 
 	_eip = root->regs.eip;
diff --git a/kernel/features/syscall.c b/kernel/features/syscall.c
index eaa09b3..519532c 100644
--- a/kernel/features/syscall.c
+++ b/kernel/features/syscall.c
@@ -9,7 +9,6 @@
 #include <str.h>
 #include <sys.h>
 
-int i = 0;
 void syscall_handler(struct regs *r)
 {
 	enum sys num = r->eax;
diff --git a/kernel/inc/load.h b/kernel/inc/load.h
index 60fecf9..597d3b5 100644
--- a/kernel/inc/load.h
+++ b/kernel/inc/load.h
@@ -5,6 +5,58 @@
 
 #include <proc.h>
 
+#define ELF_MAG 0x7F // 0
+#define ELF_32 (1) // 4: 32-bit Architecture
+#define ELF_LITTLE (1) // 5: Little Endian
+#define ELF_CURRENT (1) // 6: ELF Current Version
+#define ELF_386 (3) // header->machine x86 machine type
+
+#define ET_NONE 0 // Unkown type
+#define ET_REL 1 // Relocatable file
+#define ET_EXEC 2 // Executable file
+
+struct elf_header {
+	u8 ident[16];
+	u16 type;
+	u16 machine;
+	u32 version;
+	u32 entry;
+	u32 phoff;
+	u32 shoff;
+	u32 flags;
+	u16 ehsize;
+	u16 phentsize;
+	u16 phnum;
+	u16 shentsize;
+	u16 shnum;
+	u16 shstrndx;
+};
+
+struct elf_section_header {
+	u32 name;
+	u32 type;
+	u32 flags;
+	u32 addr;
+	u32 offset;
+	u32 size;
+	u32 link;
+	u32 info;
+	u32 addralign;
+	u32 entsize;
+};
+
+struct elf_program_header {
+	u32 type;
+	u32 offset;
+	u32 vaddr;
+	u32 paddr;
+	u32 filesz;
+	u32 memsz;
+	u32 flags;
+	u32 align;
+};
+
 void bin_load(char *path, struct proc *proc);
+void elf_load(char *path, struct proc *proc);
 
 #endif