Some work on the elf loader

5 files changed, 71 insertions, 181 deletions

diff --git a/src/kernel/fs/elf.c b/src/kernel/fs/elf.c
new file mode 100644
index 0000000..2f1b463
--- /dev/null
+++ b/src/kernel/fs/elf.c
@@ -0,0 +1,68 @@
+#include <kernel/system.h>
+#include <kernel/fs/elf.h>
+#include <kernel/lib/stdio.h>
+#include <kernel/memory/alloc.h>
+#include <kernel/lib/lib.h>
+#include <kernel/memory/paging.h>
+
+#define USER_OFFSET 0x40000000
+#define USER_STACK 0xF0000000
+#define PT_LOAD 0x1
+
+int is_elf(char *elf_data)
+{
+	elf_header_t *header = (elf_header_t *)elf_data;
+	if (header->ident[0] == 0x7f && header->ident[1] == 'E' && header->ident[2] == 'L' &&
+	    header->ident[3] == 'F') {
+		serial_printf("Buffer is valid ELF file!");
+		return 1;
+	}
+	return 0;
+}
+
+uint32_t load_elf(char *elf_data)
+{
+	uint32_t v_begin, v_end;
+	elf_header_t *hdr;
+	elf_program_header_t *p_entry;
+	elf_section_header_t *s_entry;
+
+	hdr = (elf_header_t *)elf_data;
+	p_entry = (elf_program_header_t *)(elf_data + hdr->phoff);
+
+	s_entry = (elf_section_header_t *)(elf_data + hdr->shoff);
+
+	if (is_elf(elf_data) == 0)
+		return 0;
+
+	for (int pe = 0; pe < hdr->phnum; pe++, p_entry++) {
+		if (p_entry->type == PT_LOAD) {
+			v_begin = p_entry->vaddr;
+			v_end = p_entry->vaddr + p_entry->memsz;
+			if (v_begin < USER_OFFSET) {
+				printf("INFO: load_elf(): can't load executable below %x\n",
+				       USER_OFFSET);
+				return 0;
+			}
+
+			if (v_end > USER_STACK) {
+				printf("INFO: load_elf(): can't load executable above %x\n",
+				       USER_STACK);
+				return 0;
+			}
+
+			printf("ELF: entry flags: %x (%d)\n", p_entry->flags, p_entry->flags);
+
+			memcpy((uint8_t *)v_begin, (uint8_t *)(elf_data + p_entry->offset),
+			       p_entry->filesz);
+			if (p_entry->memsz > p_entry->filesz) {
+				char *p = (char *)p_entry->vaddr;
+				for (int i = p_entry->filesz; i < (int)(p_entry->memsz); i++) {
+					p[i] = 0;
+				}
+			}
+		}
+	}
+
+	return hdr->entry;
+}
diff --git a/src/kernel/fs/elf.h b/src/kernel/fs/elf.h
index ea8493b..ee89000 100644
--- a/src/kernel/fs/elf.h
+++ b/src/kernel/fs/elf.h
@@ -48,6 +48,7 @@ typedef struct {
 	uint32_t align;
 } elf_program_header_t;
 
-void elf_init();
+int is_elf(char *data);
+uint32_t load_elf(char *elf_data);
 
-#endif
\ No newline at end of file
+#endif
diff --git a/src/kernel/fs/elfloader.c b/src/kernel/fs/elfloader.c
deleted file mode 100644
index fa537f6..0000000
--- a/src/kernel/fs/elfloader.c
+++ /dev/null
@@ -1,61 +0,0 @@
-#include <kernel/system.h>
-#include <kernel/fs/elf.h>
-#include <kernel/lib/stdio.h>
-#include <kernel/memory/alloc.h>
-#include <kernel/lib/lib.h>
-#include <kernel/memory/paging.h>
-#include "load.h"
-
-int elf_probe(uint8_t *buf)
-{
-	elf_header_t *header = (elf_header_t *)buf;
-	if (header->ident[0] == 0x7f && header->ident[1] == 'E' && header->ident[2] == 'L' &&
-	    header->ident[3] == 'F') {
-		serial_printf("Buffer is valid ELF file!");
-		return 1;
-	}
-	return 0;
-}
-
-uint8_t elf_start(uint8_t *buf)
-{
-	elf_header_t *header = (elf_header_t *)buf;
-	serial_printf("Type: %s%s%s", header->ident[4] == 1 ? "32bit " : "64 bit",
-		      header->ident[5] == 1 ? "Little Endian " : "Big endian ",
-		      header->ident[6] == 1 ? "True ELF " : "buggy ELF ");
-	if (header->type != 2) {
-		serial_printf("File is not executable!");
-		return 0;
-	}
-
-	uint32_t phys_loc = loader_get_unused_load_location();
-	elf_program_header_t *ph = (elf_program_header_t *)(buf + header->phoff);
-	for (int i = 0; i < header->phnum; i++, ph++) {
-		switch (ph->type) {
-		case 0:
-			break;
-		case 1:
-			serial_printf(
-				"LOAD: offset 0x%x vaddr 0x%x paddr 0x%x filesz 0x%x memsz 0x%x",
-				ph->offset, ph->vaddr, ph->paddr, ph->filesz, ph->memsz);
-			paging_map(phys_loc, ph->vaddr, PT_PRESENT | PT_RW | PT_USED);
-			halt_loop();
-			memcpy((void *)ph->vaddr, buf + ph->offset, ph->filesz);
-			break;
-		default:
-			serial_printf("Unsupported type! Bail out!");
-			return 0;
-		}
-	}
-
-	return 0;
-}
-
-void elf_init()
-{
-	loader_t *elfloader = (loader_t *)kmalloc(sizeof(loader_t));
-	elfloader->name = "ELF32";
-	elfloader->probe = (void *)elf_probe;
-	elfloader->start = (void *)elf_start;
-	register_loader(elfloader);
-}
\ No newline at end of file
diff --git a/src/kernel/fs/load.c b/src/kernel/fs/load.c
deleted file mode 100644
index d6451c7..0000000
--- a/src/kernel/fs/load.c
+++ /dev/null
@@ -1,83 +0,0 @@
-#include <kernel/fs/load.h>
-#include <kernel/fs/marfs/marfs.h>
-#include <kernel/fs/ata_pio.h>
-#include <kernel/fs/atapi_pio.h>
-#include <kernel/system.h>
-#include <kernel/fs/iso9660/iso9660.h>
-#include <kernel/memory/alloc.h>
-#include <kernel/lib/stdio.h>
-#include <kernel/lib/lib.h>
-
-void load_binaries()
-{
-	userspace = (uint32_t)kmalloc(10000);
-	font = (struct font *)kmalloc(100000);
-	; // High quality shit
-
-	uint8_t boot_drive_id = (uint8_t)(*((uint8_t *)0x9000));
-	if (boot_drive_id != 0xE0) {
-		struct ata_interface *primary_master = new_ata(1, 0x1F0);
-		marfs_init(primary_master);
-		marfs_read_whole_file(4, (uint8_t *)userspace);
-		marfs_read_whole_file(5, (uint8_t *)font);
-	} else {
-		char *font_p[] = { "FONT.BIN" };
-		struct iso9660_entity *font_e = ISO9660_get(font_p, 1);
-		if (!font_e)
-			panic("Font not found!");
-		ATAPI_granular_read(1 + (font_e->length / 2048), font_e->lba, (uint8_t *)font);
-		kfree(font_e);
-
-		char *user_p[] = { "USER.BIN" };
-		struct iso9660_entity *user_e = ISO9660_get(user_p, 1);
-		if (!user_e)
-			panic("Userspace binary not found!");
-		ATAPI_granular_read(1 + (user_e->length / 2048), user_e->lba, (uint8_t *)userspace);
-		kfree(user_e);
-	}
-	vga_log("Successfully loaded binaries");
-}
-
-#define MAX_LOADERS 16
-
-loader_t **loaders = 0;
-uint8_t last_loader = 0;
-
-uint32_t last_load_loc = 0x400000;
-
-void loader_init()
-{
-	serial_printf("Setting up loader");
-	loaders = (loader_t **)kmalloc(MAX_LOADERS * sizeof(uint32_t));
-	memset(loaders, 0, MAX_LOADERS * sizeof(uint32_t));
-}
-
-void register_loader(loader_t *load)
-{
-	if (last_loader + 1 > MAX_LOADERS)
-		return;
-	if (!load)
-		return;
-	loaders[last_loader] = load;
-	last_loader++;
-	serial_printf("Registered %s loader as id %d", load->name, last_loader - 1);
-}
-
-uint32_t loader_get_unused_load_location()
-{
-	last_load_loc += 0x400000;
-	return last_load_loc;
-}
-
-uint8_t exec_start(uint8_t *buf)
-{
-	for (int i = 0; i < MAX_LOADERS; i++) {
-		if (!loaders[i])
-			break;
-		void *priv = loaders[i]->probe(buf);
-		if (priv) {
-			return loaders[i]->start(buf, priv);
-		}
-	}
-	return 0;
-}
\ No newline at end of file
diff --git a/src/kernel/fs/load.h b/src/kernel/fs/load.h
deleted file mode 100644
index 0343092..0000000
--- a/src/kernel/fs/load.h
+++ /dev/null
@@ -1,35 +0,0 @@
-#ifndef MELVIX_LOAD_H
-#define MELVIX_LOAD_H
-
-#include <stdint.h>
-
-uint32_t userspace;
-
-struct font *font;
-
-struct font {
-	uint16_t font_32[758][32];
-	uint16_t font_24[758][24];
-	uint8_t font_16[758][16];
-	uint16_t cursor[19];
-};
-
-void load_binaries();
-
-typedef struct {
-	char *name;
-
-	void *(*probe)(uint8_t *buf);
-
-	uint8_t (*start)(uint8_t *buf, void *priv);
-} loader_t;
-
-void loader_init();
-
-void register_loader(loader_t *load);
-
-uint8_t exec_start(uint8_t *buf);
-
-uint32_t loader_get_unused_load_location();
-
-#endif
\ No newline at end of file