From: jacob <jacob@ainfvec.fac.cs.cmu.edu>
Date: Wed, 10 Sep 2008 21:12:02 +0000 (-0400)
Subject: add elf loader to grub boot; doesn't do aseg opening yet (todo!)
X-Git-Url: http://git.joshuawise.com/netwatch.git/commitdiff_plain/d56898ee77b960cfe7f1d75bca2725d9d5337553

add elf loader to grub boot; doesn't do aseg opening yet (todo!)
---

diff --git a/grubload/Makefile b/grubload/Makefile
index 971fb5c..041f09c 100644
--- a/grubload/Makefile
+++ b/grubload/Makefile
@@ -1,4 +1,4 @@
-OBJS=multiboot_c.o multiboot_asm.o console.o minilib.o
+OBJS=multiboot_c.o multiboot_asm.o console.o minilib.o loader.o
 CC=gcc
 CFLAGS=-nostdlib -I../include -I. -fno-builtin -nostdinc
 
diff --git a/grubload/loader.c b/grubload/loader.c
new file mode 100644
index 0000000..4ecba2a
--- /dev/null
+++ b/grubload/loader.c
@@ -0,0 +1,49 @@
+#include "minilib.h"
+#include "../include/elf.h"
+
+static const unsigned char elf_ident[4] = { 0x7F, 'E', 'L', 'F' }; 
+
+int load_elf (char * buf, int size) {
+
+	Elf32_Ehdr * elf_hdr = (Elf32_Ehdr *) buf;
+	Elf32_Shdr * elf_sec_hdrs = (Elf32_Shdr *) (buf + elf_hdr->e_shoff);
+
+	/* Sanity check on ELF file */
+	if (memcmp(elf_hdr->e_ident, elf_ident, sizeof(elf_ident))) return -1;
+	if (elf_hdr->e_type != ET_EXEC) return -1;
+	if (elf_hdr->e_machine != EM_386) return -1;
+	if (elf_hdr->e_version != EV_CURRENT) return -1;
+	if (size < sizeof(Elf32_Ehdr)) return -1;
+	if (((char *)&elf_sec_hdrs[elf_hdr->e_shnum]) > (buf + size)) return -1;
+
+	char * string_table = buf + elf_sec_hdrs[elf_hdr->e_shstrndx].sh_offset;
+
+	if (string_table > (buf + size)) return -1;
+
+	int i;
+	for (i = 0; i < elf_hdr->e_shnum; i++) {
+
+		if (elf_sec_hdrs[i].sh_name == SHN_UNDEF) {
+			continue;
+		}
+
+		char * section_name = string_table + elf_sec_hdrs[i].sh_name;
+
+		if ((elf_sec_hdrs[i].sh_type != SHT_PROGBITS) || !(elf_sec_hdrs[i].sh_flags & SHF_ALLOC)) {
+			puts("Skipping ");
+			puts(section_name);
+			puts("\n");
+			continue;
+		}
+
+		puts("Loading ");
+		puts(section_name);
+		puts("\n");
+
+		memcpy(elf_sec_hdrs[i].sh_addr,
+		       buf + elf_sec_hdrs[i].sh_offset,
+		       elf_sec_hdrs[i].sh_size);
+	}
+
+	return 0;
+}
diff --git a/grubload/loader.h b/grubload/loader.h
new file mode 100644
index 0000000..e5d5c52
--- /dev/null
+++ b/grubload/loader.h
@@ -0,0 +1,2 @@
+int load_elf (char * buf, int size) ;
+
diff --git a/grubload/minilib.c b/grubload/minilib.c
index f2ab662..b9813d7 100644
--- a/grubload/minilib.c
+++ b/grubload/minilib.c
@@ -20,6 +20,24 @@ void memmove(unsigned char *dest, unsigned char *src, int bytes)
 			*(dest++) = *(src++);
 }
 
+int memcmp (unsigned char *a2, unsigned char *a1, int bytes) {
+	while (bytes--)
+	{
+		if (*(a2++) != *(a1++))
+			return 1;
+	}
+	return 0;
+}
+
+int strcmp (unsigned char *a2, unsigned char *a1) {
+	while (1) {
+		if (*a2 != *a1) return 1;
+		if (*a2 == 0) return 0;
+		a1++;
+		a2++;
+	}
+}
+
 int strlen(char *c)
 {
 	int l = 0;
diff --git a/grubload/minilib.h b/grubload/minilib.h
new file mode 100644
index 0000000..e0fc16b
--- /dev/null
+++ b/grubload/minilib.h
@@ -0,0 +1,33 @@
+#ifndef __MINILIB_H
+#define __MINILIB_H
+
+#define MINILIB 1
+
+#ifndef __int8_t_defined
+# define __int8_t_defined
+typedef signed char             int8_t;
+typedef short int               int16_t;
+typedef int                     int32_t;
+# if __WORDSIZE == 64
+typedef long int                int64_t;
+# else
+__extension__
+typedef long long int           int64_t;
+# endif
+#endif
+
+/* Unsigned.  */
+typedef unsigned char           uint8_t;
+typedef unsigned short int      uint16_t;
+#ifndef __uint32_t_defined
+typedef unsigned int            uint32_t;
+# define __uint32_t_defined
+#endif
+#if __WORDSIZE == 64
+typedef unsigned long int       uint64_t;
+#else
+__extension__
+typedef unsigned long long int  uint64_t;
+#endif
+
+#endif
diff --git a/grubload/multiboot_c.c b/grubload/multiboot_c.c
index c87b675..f871687 100644
--- a/grubload/multiboot_c.c
+++ b/grubload/multiboot_c.c
@@ -33,7 +33,8 @@ void c_start(unsigned int magic, struct mb_info *wee)
 	puts("Grubptr is: ");
 	puthex(*grubptr);
 	puts("\n");
-	
+
+
 	for (i = 0; i < wee->mod_cnt; i++)
 	{
 		puts("Module:\n");
@@ -41,6 +42,16 @@ void c_start(unsigned int magic, struct mb_info *wee)
 		puts("  Size: "); puthex(wee->mods[i].mod_end - wee->mods[i].mod_start); puts("\n");
 		puts("  Name: "); puts(wee->mods[i].mod_string); puts("\n");
 	}
+
+	if ((wee->mod_cnt != 1) || (strcmp(wee->mods[0].mod_string, "aseg.elf")))
+	{
+		puts("Expected 1 module called aseg.elf.\n");
+		while(1) asm("hlt");
+	}
+
+	load_elf(wee->mods[0].mod_start, wee->mods[0].mod_end - wee->mods[0].mod_start);
+
+
 	while (1)
 		;
 }
diff --git a/include/elf.h b/include/elf.h
index 7240b69..0d5abbd 100644
--- a/include/elf.h
+++ b/include/elf.h
@@ -21,7 +21,9 @@
 #ifndef _ELF_H
 #define	_ELF_H 1
 
+#ifndef MINILIB
 #include <stdint.h>
+#endif
 
 /* Standard ELF types.  */